tag:theconversation.com,2011:/us/topics/mercury-4351/articlesMercury – The Conversation2023-12-05T13:17:38Ztag:theconversation.com,2011:article/2168062023-12-05T13:17:38Z2023-12-05T13:17:38ZScientists have been researching superconductors for over a century, but they have yet to find one that works at room temperature − 3 essential reads<figure><img src="https://images.theconversation.com/files/560888/original/file-20231121-15-k3mvg.jpg?ixlib=rb-1.1.0&rect=4%2C8%2C1417%2C2095&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The search for the room-temperature superconductor continues. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/superconductivity-royalty-free-image/521405206?phrase=superconductor&adppopup=true">Charles O'Rear/Corbis Documentary via Getty Images</a></span></figcaption></figure><p>If you hadn’t heard about superconductors before 2023, odds are you know what they are now. Researchers raised eyebrows early in the year with <a href="https://www.science.org/content/article/short-spectacular-life-viral-room-temperature-superconductivity-claim">claims of operational room-temperature superconductors</a>, though none has been substantiated, and <a href="https://www.nature.com/articles/s41586-023-05742-0">one paper</a> from researchers at the University of Rochester was <a href="https://doi.org/10.1038/s41586-023-06774-2">retracted by the journal Nature</a> at the authors’ request in November. </p>
<p>But the hunt <a href="https://www.energy.gov/science/doe-explainssuperconductivity">for a superconductor</a> – that is, a material that can conduct electricity without resistance – that can operate at room temperature is nothing new. </p>
<p>Right now, superconductors can operate only at very cold temperatures. So, finding one that could work at room temperature without needing to be kept in a cold chamber could revolutionize everything <a href="https://theconversation.com/physicists-hunt-for-room-temperature-superconductors-that-could-revolutionize-the-worlds-energy-system-80707">from power grids</a> and <a href="https://theconversation.com/room-temperature-superconductors-could-revolutionize-electronics-an-electrical-engineer-explains-the-materials-potential-201849">medical equipment</a> to <a href="https://theconversation.com/room-temperature-superconductors-could-revolutionize-electronics-an-electrical-engineer-explains-the-materials-potential-201849">quantum computing</a>. But physicists first have to figure out how to make them work. </p>
<p>A Dutch physicist <a href="https://theconversation.com/superconductivity-at-room-temperature-remains-elusive-a-century-after-a-nobel-went-to-the-scientist-who-demonstrated-it-below-450-degrees-fahrenheit-213959">discovered the phenomenon of superconductivity</a> in the early 20th century, and since then, labs around the world have tested materials that can reach a superconductive state at <a href="https://doi.org/10.1103/PhysRevB.50.4260">warmer and warmer temperatures</a>. </p>
<p>So, how do these materials manage to conduct electricity without resistance, and what sorts of technological possibilities lie on the horizon, with superconductor research improving every year? Here are three stories from The Conversation’s archive that explore the history, science and future of this incredible physical phenomenon. </p>
<h2>1. Physics behind the phenomenon</h2>
<p>How is it even possible to generate a current with zero electrical resistance, the basis for superconductivity? In order to do so, you must <a href="https://doi.org/10.1103/PhysRev.108.1175">keep your conducting metal cold</a>. Really cold. Like, hundreds of degrees below zero. </p>
<p>“At normal temperatures, electrons move in somewhat erratic paths. They can generally succeed in moving through a wire freely, but every once in a while they collide with the nuclei of the material,” <a href="https://theconversation.com/how-do-superconductors-work-a-physicist-explains-what-it-means-to-have-resistance-free-electricity-202308">wrote Mishkat Bhattacharya</a>, <a href="https://scholar.google.com/citations?user=5gCcMuMAAAAJ&hl=en&oi=sra">a physicist at</a> Rochester Institute of Technology. “These collisions are what obstruct the flow of electrons, cause resistance and heat up the material.”</p>
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<figcaption><span class="caption">Superconductive materials repel magnetic fields, making it possible to levitate a magnet above a superconductor.</span></figcaption>
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<p>Normally, the nuclei of all atoms vibrate constantly, and they can bump into each other. In superconducting materials, the electrons in the current pass from atom to atom while vibrating at the same frequency as the nuclei of the atoms in the superconducting metal. This means that instead of colliding and generating heat, they’re moving in a <a href="https://www.energy.gov/science/bes/articles/electrons-line-dance-superconductor">smooth and coordinated way</a>. And it’s the cold temperatures that allow for this coordinated movement. </p>
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<a href="https://theconversation.com/how-do-superconductors-work-a-physicist-explains-what-it-means-to-have-resistance-free-electricity-202308">How do superconductors work? A physicist explains what it means to have resistance-free electricity</a>
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<h2>2. A century of superconductivity</h2>
<p>Mercury was the first material <a href="https://doi.org/10.1063/1.3490499">discovered as a superconducter</a>, by <a href="https://www.nobelprize.org/prizes/physics/1913/onnes/facts/">Heike Kamerlingh Onnes</a> in 1911. His team had to cool liquid helium to -454 degrees Fahrenheit (-270 degrees Celsius) to observe the effect. They used wires made of mercury to send a current through the material, and then measured the effect of electrical resistance as “near enough null.” </p>
<p>Onnes and his team repeated the experiment several times to make sure the effect they’d observed was, in fact, superconductivity, and they also troubleshot all other possible explanations for the effect – electrical faults, open currents and so on. But they kept finding the same result, and after three years of testing, Onnes was able to demonstrate currents with truly zero resistance. </p>
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<span class="caption">The resistance of mercury as recorded on Oct. 26, 1911, by Heike Kamerlingh Onnes’ lab.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Superconductivity_1911.png">Heike Kamerlingh Onnes via Wikimedia Commons</a></span>
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<p>“Superconductivity has always been tricky to prove because some metals can masquerade as superconductors,” <a href="https://theconversation.com/superconductivity-at-room-temperature-remains-elusive-a-century-after-a-nobel-went-to-the-scientist-who-demonstrated-it-below-450-degrees-fahrenheit-213959">wrote David D. Nolte</a>, <a href="https://galileo-unbound.blog/books-by-d-d-nolte/">an author of history of science books and a physicist at Purdue</a>. “The lessons learned by Onnes a century ago – that these discoveries require time, patience and, most importantly, proof of currents that never stop – are still relevant today.”</p>
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Read more:
<a href="https://theconversation.com/superconductivity-at-room-temperature-remains-elusive-a-century-after-a-nobel-went-to-the-scientist-who-demonstrated-it-below-450-degrees-fahrenheit-213959">Superconductivity at room temperature remains elusive a century after a Nobel went to the scientist who demonstrated it below -450 degrees Fahrenheit</a>
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<h2>3. A superconductive future</h2>
<p>One of the most important applications of a future room-temperature superconductor would be decreasing the heat wasted from electronics. Not only could electronics like cellphones and computers run much <a href="https://theconversation.com/physicists-hunt-for-room-temperature-superconductors-that-could-revolutionize-the-worlds-energy-system-80707">more quickly and efficiently</a>, but on a larger scale, electric grids, power lines and data centers could decrease <a href="https://www.eia.gov/tools/faqs/faq.php?id=105&t=3">their wasted heat</a>. This could be a huge win for the environment. </p>
<p>“If we succeed in making a room-temperature superconductor, then we can address the billions of dollars that it costs in wasted heat to transmit energy from power plants to cities,” <a href="https://theconversation.com/physicists-hunt-for-room-temperature-superconductors-that-could-revolutionize-the-worlds-energy-system-80707">wrote Pegor Aynajian</a>, <a href="https://scholar.google.com/citations?user=B_5QhO4AAAAJ&hl=en">a physicist at</a> Binghamton University, State University of New York. “Solar energy harvested in the vast empty deserts around the world could be stored and transmitted without any loss of energy, which could power cities and dramatically reduce greenhouse gas emissions.”</p>
<p>A type of superconductor made from a ceramiclike material <a href="https://www.nobelprize.org/prizes/physics/1987/summary/">discovered by scientists</a> at <a href="https://www.zurich.ibm.com/">IBM in Switzerland</a> could be one path to a room-temperature superconductor. Already, this class of materials has been shown to <a href="https://www.quantamagazine.org/high-temperature-superconductivity-understood-at-last-20220921/">work at higher – though still frigid – temperatures</a>, closer to -300 F (-184 C) than conventional superconductors like Onnes’ original mercury wires. </p>
<p>But while a room-temperature superconductor could revolutionize electronics and energy transmission, the right material still remains elusive. As Aynajian puts it, a room-temperature superconductor is quite literally “the next million-dollar question.”</p>
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Read more:
<a href="https://theconversation.com/physicists-hunt-for-room-temperature-superconductors-that-could-revolutionize-the-worlds-energy-system-80707">Physicists hunt for room-temperature superconductors that could revolutionize the world's energy system</a>
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<p><em>This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/216806/count.gif" alt="The Conversation" width="1" height="1" />
Claims about the discovery of a coveted room-temperature superconductor peppered the news in 2023. We pulled three stories from our archives on what superconductivity is and why scientists study it.Mary Magnuson, Assistant Science EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2136752023-10-02T15:01:33Z2023-10-02T15:01:33ZMercury: shrinking planet is still getting smaller – new research<figure><img src="https://images.theconversation.com/files/548561/original/file-20230915-15-alw9f3.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1664%2C749&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Perspective view of a lobate scarp on Mercury named Carnegie Rupes, colour-coded according to surface altitude. The crater near the middle is nearly 40 km across.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/a-striking-perspective">NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington</a></span></figcaption></figure><p>Planetary scientists have long known that Mercury has been shrinking for billions of years. Despite being the closest planet to the Sun, its interior has been cooling down as internal heat leaks away. This means that the rock (and, within that, the metal) of which it is composed must have contracted slightly in volume. </p>
<p>It is unknown, however, to what extent the planet is still shrinking today – and, if so, for how long that is likely to continue. Now our new paper, <a href="https://www.nature.com/articles/s41561-023-01281-5">published in Nature Geoscience</a>, offers fresh insight.</p>
<p>Because Mercury’s interior is shrinking, its surface (crust) has progressively less area to cover. It responds to this by developing “thrust faults” – where one tract of terrain gets pushed over the adjacent terrain (see image below). This is like the wrinkles that form on an apple as it ages, except that an apple shrinks because it is drying out whereas Mercury shrinks because of thermal contraction of its interior.</p>
<p>The first evidence of Mercury’s shrinkage came in 1974 when the Mariner 10 mission transmitted pictures of kilometres-high scarps (ramp-like slopes) snaking their way for hundreds of kilometres across the terrain. Messenger, which orbited Mercury 2011-2015, showed many more “lobate scarps” (as they had become known) in all parts of the globe. </p>
<p>From such observations, it was possible to deduce that gently dipping geological faults, known as thrusts, approach the surface below each scarp and are a response to Mercury having shrunk in radius by a total of about 7km. </p>
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<a href="https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Block diagram showing a thrust fault" src="https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548543/original/file-20230915-17-tn3nfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A cross-section though Mercury’s crust.</span>
<span class="attribution"><span class="source">D A Rothery</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>But when did this happen? The accepted way to work out the age of Mercury’s surface is to count the density of impact craters. The older the surface, the more craters. But this method is tricky, because the rate of impacts that produce craters was much greater in the deep past.</p>
<p>However, it was always clear that Mercury’s scarps must be fairly ancient, because although they cut through some older craters, quite a few younger craters are superimposed upon the scarps and so the scarps must be older than those.</p>
<h2>When did that scarp last move?</h2>
<p>The consensus view is that Mercury’s scarps are mostly about 3 billion years old. But are all of them that old? And did the older ones cease moving long ago or are they still active today?</p>
<p>We should not expect that the thrust fault below each scarp has moved only once. The biggest earthquake on Earth in recent years, the magnitude 9 <a href="https://education.nationalgeographic.org/resource/tohoku-earthquake-and-tsunami/">Tohoku earthquake</a> offshore of Japan in 2011 which caused the Fukushima disaster, was the result of a sudden jump by 20 metres along a 100km length of the responsible thrust fault.</p>
<p>Mercury’s biggest “earthquakes” are probably smaller. To accumulate the 2-3km of total shortening that can be measured across a typical scarp on Mercury would take hundreds of magnitude 9 “earthquakes”, or more likely millions of smaller events, which could have been spread out over billions of years.</p>
<p>Getting a handle on the scale and duration of fault movements on Mercury is important, because we would not expect Mercury’s thermal contraction to have entirely finished, even though this should be slowing down.</p>
<h2>Cracking up</h2>
<p>Until now, evidence has been sparse. But our team found unambiguous signs that many scarps have continued to move in geologically recent times, even if they were initiated billions of years ago.</p>
<p>This work was triggered when a PhD student at Open University in the UK, Ben Man, noticed that some scarps have small fractures piggy-backing on their stretched upper surfaces. He interpreted these as “grabens”, the geological word to describe a strip of ground dropped down between two parallel faults. </p>
<p>This typically happens when the crust is stretched. Stretching may seem surprising on Mercury, where overall the crust is being compressed, but Man realised that these grabens would occur if a thrust slice of crust has been bent as it is pushed over the adjacent terrain. If you try to bend a piece of toast, it may crack in a similar way.</p>
<p>The grabens are less than 1km wide and less than about 100 meters deep. Such comparatively small features must be much younger than the ancient structure on which they sit, otherwise they would have already been erased from view by impacts tossing material across the surface in a process aptly named “<a href="https://en.wikipedia.org/wiki/Impact_gardening">impact gardening</a>”.</p>
<p>Based on the rate of blurring resulting from impact gardening, we calculated that the majority of grabens are less than about 300 million years old. This suggests that the latest movement must have happened equally “recently”. </p>
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<img alt="Lobate scarp, with visible grabens on its crest." src="https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=457&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=457&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=457&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=574&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=574&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548553/original/file-20230915-23-q7pp3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=574&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Lobate scarp, with visible grabens on its crest.</span>
<span class="attribution"><span class="source">NASA</span></span>
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<p>Working with the most detailed images provided by MESSENGER, Man found 48 large lobate scarps that definitely have small grabens. A further 244 were topped by “probable” grabens – which aren’t seen quite clearly enough on the best MESSENGER images.</p>
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<img alt="Global map of shortening structures atop lobate scarps" src="https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548554/original/file-20230915-17-kpyawm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Global map of shortening structures atop lobate scarps. Triangles = definite. Circles = probable.</span>
<span class="attribution"><span class="source">D A Rothery</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>These are now prime targets for confirmation by the imaging system of the joint European/Japanese <a href="https://theconversation.com/europe-blasts-off-to-mercury-heres-the-rocket-science-104641">BepiColombo</a> mission, which should start operating in orbit around Mercury early in 2026. </p>
<h2>Lessons from the Moon</h2>
<p>The Moon has also cooled and contracted. Its lobate scarps are considerably smaller and less spectacular than those on Mercury, but on the Moon we know for sure that as well as being geologically recent, some are active today. </p>
<p>This is because <a href="https://theconversation.com/the-moon-is-still-geologically-active-study-suggests-116768">recent reanalysis</a> of the locations of moonquakes recorded by seismometers (vibration detectors) left on the Moon’s surface by several Apollo missions shows that moonquakes are clustered close to lobate scarps. </p>
<p>Also, the most detailed images of the Moon’s surface from orbit reveal the tracks made by boulders bouncing down scarp faces, presumably after being dislodged by moonquakes. Much smaller in scale than Mercury’s grabens, similar logic applies to these boulder tracks: they would become erased from visibility after only a few million years, so they must be young. </p>
<p>BepiColombo won’t be landing and so we have no prospect of collecting any seismic data on Mercury. However, as well as showing small grabens more clearly, its most detailed images might reveal boulder tracks that could be additional evidence of recent quakes. I am looking forward to finding out.</p>
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<a href="https://theconversation.com/bepicolombos-first-close-up-pictures-of-mercurys-surface-hint-at-answers-to-the-planets-secrets-168159">BepiColombo's first close-up pictures of Mercury's surface hint at answers to the planet's secrets</a>
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<a href="https://theconversation.com/the-more-we-learn-about-mercury-the-weirder-it-seems-55972">The more we learn about Mercury, the weirder it seems</a>
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<img src="https://counter.theconversation.com/content/213675/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Rothery is Professor of Planetary Geosciences at the Open University. He is co-leader of the European Space Agency's Mercury Surface and Composition Working Group, and a Co-Investigator on MIXS (Mercury Imaging X-ray Spectrometer) that is now on its way to Mercury on board the European Space Agency's Mercury orbiter BepiColombo. He has received funding from the UK Space Agency and the Science & Technology Facilities Council for work related to Mercury and BepiColombo, and from the European Commission under its Horizon 2020 programme for work on planetary geological mapping (776276 Planmap). He is author of Planet Mercury - from Pale Pink Dot to Dynamic World (Springer, 2015), Moons: A Very Short Introduction (Oxford University Press, 2015) and Planets: A Very Short Introduction (Oxford University Press, 2010). He is Educator on the Open University's free learning Badged Open Course (BOC) on Moons and its equivalent FutureLearn Moons MOOC, and chair of the Open University's level 2 course on Planetary Science and the Search for Life.</span></em></p>Mercury has shrunk by7 km. Most of this happened long ago, but now we have evidence that it continues.David Rothery, Professor of Planetary Geosciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2050322023-05-08T02:51:49Z2023-05-08T02:51:49ZPeople are complaining about Mercury in retrograde. But what does it actually mean?<figure><img src="https://images.theconversation.com/files/524808/original/file-20230508-186646-o6xtme.png?ixlib=rb-1.1.0&rect=296%2C2%2C1177%2C809&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.solarsystemscope.com/">SolarSystemScope.com</a></span></figcaption></figure><p>Mercury is the closest planet to the Sun, whipping around <a href="https://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html">our star every 88 days compared to Earth’s 365.25 days</a>. Mercury will also be the first planet destroyed when the Sun expands on its way to becoming <a href="https://www.space.com/22471-red-giant-stars.html">a red giant in about 5 billion years</a>.</p>
<p>So it seems a bit rough that we <a href="https://edition.cnn.com/cnn-underscored/health-fitness/mercury-retrograde-2023">blame Mercury for all our problems</a> three to four times a year when it’s in retrograde. But what does it mean when we say Mercury is “in retrograde”?</p>
<figure class="align-left ">
<img alt="An image of Mercury - a partially obscured dark grey sphere with lots of texture created by many craters on its surface, on a black background" src="https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524561/original/file-20230505-23-7hoqy7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Image of Mercury from MESSENGER’s Wide Angle Camera.</span>
<span class="attribution"><span class="source">NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie</span></span>
</figcaption>
</figure>
<h2>A matter of orbits</h2>
<p>Retrograde motion means a planet is moving in the opposite direction to normal around the Sun. However, the planets never actually change direction. What we are talking about is <em>apparent</em> retrograde motion, when to us on Earth it looks like a planet is moving across the sky in the opposite direction to its usual movement.</p>
<p>Because Mercury is closest to the Sun and has the fastest orbit, it appears to move backwards in the sky more often than any other planet.</p>
<p>Let’s use my dog Astro to help explain what’s happening when we see a planet in retrograde. Astro is a whippet, or a mini-greyhound, and he has a need for speed. If I take Astro for a run on my local cricket oval, he does super-speed laps on the inside while I run much more slowly around the outside.</p>
<p>If we’re both going anti-clockwise around the cricket pitch, when Astro is on the opposite side of the oval to me it looks like he’s going left while I’m jogging right. But when he gets to the same side of the oval as me, it suddenly looks like he’s running right instead of left (retrograde).</p>
<p>This happens because Astro is going much faster than me, and is inside my “orbit” of the oval.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=530&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=530&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=530&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=666&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=666&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524717/original/file-20230506-17-6xss98.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=666&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diagram of me (Laura) and Astro running around the oval, from my point of view. At the top we can see the top-down view of the oval. At the bottom we can see the side-on view. From my point of view it looks like Astro is running right-to-left when he’s on the opposite side of the oval to me, but it looks like he’s running left-to-right when he’s on the same side of the oval to me.</span>
<span class="attribution"><span class="source">Laura Driessen (author provided)</span></span>
</figcaption>
</figure>
<p>Because Mercury’s orbit is inside Earth’s orbit, seeing it from our planet is like me watching Astro run.</p>
<p>But Mercury isn’t the only planet to do this. Venus also orbits inside our orbit of the Sun, zipping around <a href="https://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html">once every 224.7 days</a>. This means Venus is in retrograde twice every three years.</p>
<figure class="align-center ">
<img alt="Diagram of the concentric rings around the Sun showing the orbits of all the planets (and Pluto)." src="https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=446&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=446&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=446&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=560&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=560&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524562/original/file-20230505-29-lvevp3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=560&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diagram of the orbits of the planets (and dwarf planet Pluto) in the Solar System. The dwarf planet Ceres orbits between Mars and Jupiter.</span>
<span class="attribution"><span class="source">NASA Space Place</span></span>
</figcaption>
</figure>
<h2>The other retrograde</h2>
<p>It works the other way around, too. The planets outside our orbit (Mars, Jupiter, Saturn, Uranus, and Neptune) also go into retrograde.</p>
<p>To work this out, we need to swap our perspective. Astro is definitely not a deep thinker, but let’s imagine for a moment that he is and think about what he sees as he runs around the oval.</p>
<p>He’s running around the oval and he starts catching me up from behind. At this moment it seems like we’re both going the same direction, to the right. But as he starts to pass me, it seems like I’m going backwards or left (retrograde) while he continues to run forwards to the right.</p>
<p>This is what happens when we look up at the sky and see one of the outer planets in retrograde.</p>
<p>Mars is in retrograde once every two years. The other planets are so far from the Sun and travelling so slowly compared to Earth that it’s almost like they’re standing still. So we see them in retrograde approximately once a year as we whip around the Sun so much faster than they do.</p>
<figure class="align-center ">
<img alt="Artist's impression of retrograde motion from Astro the whippet's perspective." src="https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524559/original/file-20230505-1338-1zsf5n.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diagram of me (Laura) and Astro running around the oval, this time from Astro’s perspective. At the top we can see the top-down view of the oval. At the bottom we can see the side-on view. From Astro’s view, it appears that I’m going backwards as he overtakes me.</span>
<span class="attribution"><span class="source">Laura Driessen (author provided)</span></span>
</figcaption>
</figure>
<h2>A well-known illusion</h2>
<p>Retrograde motion bamboozled ancient astronomers since humans started looking up in space, and we only officially figured it out when Copernicus proposed in 1543 that the planets are <a href="https://earthobservatory.nasa.gov/features/OrbitsHistory">orbiting the Sun</a> (though he wasn’t the first astronomer <a href="https://www.worldhistory.org/Aristarchus_of_Samos/">to propose this heliocentric model</a>).</p>
<p>Before Copernicus, many astronomers thought Earth was the centre of the universe and the planets were spinning around us. Astronomers like <a href="https://blog.oup.com/2017/07/planetary-astronomy-ancient-greece/">Apollonius</a> around 300 BCE saw the planets going backwards, and explained this by adding more circles called epicycles.</p>
<p>So, humans found out retrograde motion was an optical illusion 500 years ago. However, the <a href="https://theconversation.com/why-is-astronomy-a-science-but-astrology-is-not-192376">pseudoscientific practice of astrology</a> continues to ascribe a deeper meaning to this illusion.</p>
<figure class="align-center ">
<img alt="Diagram with coloured lines spanning the dates in 2023 that each planet is in retrograde." src="https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=311&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=311&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=311&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=391&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=391&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524563/original/file-20230505-23-sq5dua.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=391&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diagram of the dates in 2023 that each planet (and the two dwarf planets Pluto and Ceres) will be in retrograde.</span>
<span class="attribution"><span class="source">Laura Driessen (author provided)</span></span>
</figcaption>
</figure>
<h2>There’s a retrograde most of the time</h2>
<p>If we consider the seven planets other than Earth, at least one planet is in retrograde for 244 days of 2023 – that’s around two-thirds of the year.</p>
<figure class="align-right ">
<img alt="A white dog with a brown patch over his eye is wearing a yellow jacket and sitting in from of a dam" src="https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524718/original/file-20230506-19-5rex3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Astro the whippet thinking about all the possums he’s going to bark at later.</span>
<span class="attribution"><span class="source">Laura Driessen (author provided)</span></span>
</figcaption>
</figure>
<p>If we include the dwarf planets Pluto and Ceres (and exclude the other seven dwarf planets in the Solar System), at least one planet or dwarf planet is in retrograde for 354 days of 2023, leaving only 11 days without any retrograde motion. </p>
<p>I like to think the biggest impact the planets have on Earth is bringing wonder and joy every time we turn our eyes (and our telescopes) to the night sky. Astro, on the other hand, is happy as long as he gets to run around the oval and bark at possums. </p>
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Read more:
<a href="https://theconversation.com/from-platypus-to-parsecs-and-millicrab-why-do-astronomers-use-such-weird-units-203061">From platypus to parsecs and milliCrab: why do astronomers use such weird units?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/205032/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Nicole Driessen is part of MeerTRAP, which is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 694745).</span></em></p>There’s nothing weird happening with Mercury. In fact, most days of the year there’s at least one planet in retrograde.Laura Nicole Driessen, Postdoctoral researcher in radio astronomy, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2004542023-03-15T13:37:40Z2023-03-15T13:37:40ZCurious Kids: How are planets created?<figure><img src="https://images.theconversation.com/files/511620/original/file-20230222-16-c8nmnb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eight planets, including Earth, revolve around our Sun.</span> <span class="attribution"><span class="source">Illustration by Tobias Roetsch/Future Publishing via Getty Images</span></span></figcaption></figure><p><em>Curious Kids is a <a href="https://theconversation.com/africa/topics/curious-kids-36782">series</a> for children in which we ask experts to answer questions from kids.</em></p>
<p><strong>How are planets created? - (Saba, 6, Kenya)</strong></p>
<p>Thanks for asking such an interesting question, Saba. When you talk about planets you’re probably thinking of the planets in our solar system – the ones orbiting (circling around) our sun. There are eight of these <a href="https://solarsystem.nasa.gov/planets/overview/#otp_planets_of_our_solar_system">planets</a>. One of them is where you and I live: Earth. The others are Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.</p>
<p>There are many, many more planets way beyond our solar system and our galaxy, the Milky Way. Scientists like us, known as astronomers, have found <a href="https://www.planetary.org/worlds/exoplanets">over 5,000 planets</a> around other stars. We estimate that there may be trillions across the Universe.</p>
<p>How did they come into being? It all starts with a cloud of gas and dust.</p>
<h2>Gas and dust</h2>
<p>These clouds of gas and dust are called nebulae. They float around in space much like the clouds in our sky. There are some regions with more clouds and some with fewer and astronomers can see these using telescopes.</p>
<p>Nebulae contain gases like hydrogen, helium and carbon. When a nebula becomes dense enough its gravity pulls it together into a very dense core. This is a bit like the water in your bath swirling around the drain before getting sucked down. As the cloud gets dense it heats up. When it gets dense and hot enough the atoms – tiny building blocks for all the matter in the world – in the nebula start to fuse.</p>
<p>This process is called nuclear fusion and produces a lot of energy. And the cloud lights up like a firework. This is how a new star is born, just like our Sun was <a href="https://spaceplace.nasa.gov/sun-age/en/">4.5 billion years ago</a>.</p>
<p>A small amount of gas and dust remains around new stars in a spinning disc. Planets are formed from this disc of material.</p>
<h2>Protoplanets</h2>
<p>As the disc rotates, the material in it, small bits of rock and ice, lump together and get bigger and bigger. That forms what we call planetesimals, which collide with each other like bumper cars, creating even larger bodies known as protoplanets.</p>
<p>The protoplanets keep growing. While this is happening, they can attract gases from the surrounding disc, creating a thick atmosphere. This process is called accretion and it is how gas giant planets like Jupiter and Saturn are formed. If a protoplanet forms from heavier elements in the outer solar system it can create an ice giant. The planets Neptune and Uranus are ice giants.</p>
<p>Even after the planet is formed it can keep changing over time through processes such as volcanic activity, tectonic movement, and erosion. On Earth, mountains like Mount Kilimanjaro in Tanzania – the country next door to Kenya – formed from large volcanoes. And even larger mountains like the Himalayas have formed from tectonic plates colliding. Tectonic plates are big pieces of the Earth’s outer layer; sometimes they crash into each other and that creates things like mountains.</p>
<h2>Millions of years</h2>
<p>The way I’ve described this makes it sound as though planets are formed quickly. But the process which begins with those clouds of gas and dust takes millions of years to transform into the beautiful and diverse worlds we see in our Solar System and beyond.</p><img src="https://counter.theconversation.com/content/200454/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Cunnama receives funding from the National Research Foundation and the South African Astronomical Observatory. </span></em></p>It all starts with a cloud of gas and dust.Daniel Cunnama, Science Engagement Astronomer, South African Astronomical Observatory, South African Astronomical ObservatoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1967212022-12-19T13:36:24Z2022-12-19T13:36:24ZThe lenses of fishes’ eyes record their lifetime exposure to toxic mercury, new research finds<figure><img src="https://images.theconversation.com/files/501636/original/file-20221216-18-9nfdr9.jpg?ixlib=rb-1.1.0&rect=42%2C0%2C3983%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When fish like this netted cod are exposed to mercury, it accumulates in certain organs, including the lenses of their eyes.</span> <span class="attribution"><span class="source">Yvette Heimbrand</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Mercury pollution is a global threat to human health, especially to unborn babies and young children. Exposure to <a href="https://www.epa.gov/mercury/how-people-are-exposed-mercury">methylmercury</a>, a type that forms when mercury washes into lakes and streams, can <a href="https://doi.org/10.1002/msj.20228">harm children’s brain development</a> and cause symptoms including <a href="https://www.epa.gov/mercury/health-effects-exposures-mercury">speech impairment and muscle weakness</a> in adults who consume seafood as their main food source. Methylmercury also threatens health and reproduction in <a href="https://blogs.ifas.ufl.edu/news/2020/10/26/new-study-on-mercury-contamination-has-global-implications-for-wildlife-conservation/">fish and other wildlife</a>.</p>
<p>Humans, animals and birds are exposed to methylmercury when they eat fish and shellfish. Scientists have been working for decades to understand how and when fish accumulate mercury. This information is key for assessing mercury risks across different water bodies and landscapes, and for evaluating <a href="https://www.epa.gov/mercury/what-epa-doing-reduce-mercury-pollution-and-exposures-mercury">policy changes designed to reduce mercury emissions</a>.</p>
<p>For decades, scientists have used fish ear stones, known as otoliths, to gain insights into fish growth, migration, diet and the timing of their exposure to certain pollutants. These tiny structures of calcium carbonate, roughly the size of a pea, form inside fishes’ inner ears, where they help regulate hearing and balance. Otoliths can also provide clues about <a href="https://theconversation.com/how-is-climate-change-affecting-fishes-there-are-clues-inside-their-ears-110249">how climate change is affecting fish</a>.</p>
<p>But some pollutants, including mercury, are not incorporated into otoliths. Rather, they bind very strongly to tissues that contain sulfur, such as muscle tissues. That’s why muscle tissues have historically been used to assess contamination due to mercury pollution.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two small oval stones in a petri dish with two round eye lenses." src="https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501627/original/file-20221216-12-jdaenu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fish otoliths (above) and eye lenses (below) reveal complementary information about fish life history.</span>
<span class="attribution"><span class="source">Karin Limburg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In a newly published study, we describe a new window into individual fish’s lifetime exposure to mercury by <a href="http://dx.doi.org/10.1021/acs.estlett.2c00755">measuring it in the fish’s eyes</a>. This work is unlocking new possibilities for understanding fish lifetime exposure to this potent neurotoxicant.</p>
<h2>Clues in fish ears and eyes</h2>
<p>Today, scientists analyze mercury uptake in fish by measuring how much of it accumulates in whole bodies of fish, or often just in fillets – that is, muscle tissues. This approach tells us how much mercury the fish has accumulated over its lifetime, but it doesn’t tell us specifically when in its life the fish was exposed. A time stamp is missing.</p>
<p>Mercury concentrations can vary widely within any given fish species. For example, from 1991 to 2010, U.S. government monitors detected <a href="https://www.fda.gov/food/metals-and-your-food/mercury-levels-commercial-fish-and-shellfish-1990-2012">mercury levels in cod</a> that averaged 0.111 parts per million but ranged as high as 0.989 parts per million, a ninefold difference. This suggests that in addition to changes in mercury emissions over time, an individual fish’s movements and diets can significantly affect its exposure. </p>
<p>In our study, we propose a new method that combines measurements of otolith aging and of mercury in the lenses of a fish’s eyes to assign ages to fish eye mercury concentrations. Eye lenses are made of pure protein, are high in sulfur content and thus readily take up mercury either <a href="https://doi.org/10.1021/cb4004805">directly from water</a> or from the fish’s diet. </p>
<p>Methylmercury appears to be preferentially taken up in certain organs, <a href="https://www.doi.org/10.1073/pnas.0803147105">including eye lenses</a>. At high doses, it <a href="https://doi.org/10.1016/j.marenvres.2015.10.015">may impair fish vision</a>.</p>
<p>Our approach starts with the well-established technique of aging a fish using its otolith. As a fish grows and ages, its otoliths add yearly layers of calcium carbonate. We can estimate the fish’s age and growth rates by measuring the distance between the yearly growth layers, which are called annuli, much as foresters date trees by measuring the growth rings in their trunks. </p>
<p>We also know that a fish’s eye grows at a rate that is proportional to the growth of its otolith. So in our analysis, we apply the proportional distance that we found in the fish’s otolith to its eye lens. For our focal species, the Round Goby (<em>Neogobius melanostomus</em>), the linear relationship between these two measurements is strong. </p>
<p>As the eye lens grows and accumulates mercury, we can pinpoint when the fish was exposed using this correspondence with the otolith. And because the fish’s eye lens grows in layers throughout life, we can follow the chronology of lifetime exposure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cross-section of a catfish eye lens and graphic showing mercury exposure as recorded in the lens" src="https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=866&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=866&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=866&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1089&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1089&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501628/original/file-20221216-16-cm75i8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1089&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An eye lens of a brown bullhead catfish (top) sliced into a cross section that shows the core, formed at birth, and the layers that grow throughout life. The lower image shows the spatial pattern of the element mercury in the same lens, analyzed at the Cornell High Energy Synchrotron Source. Note that concentrations are at background levels in the layers deposited when this fish was young and increased as it got older and began to consume other fish.</span>
<span class="attribution"><span class="source">Karin Limburg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A possible climate connection</h2>
<p>With this new method, we can start to trace the chronology of a fish’s lifetime mercury exposure. And we can ask questions about how life history events, such as migration and diet shifts, or temporal events such as <a href="https://www.epa.gov/ms-htf/northern-gulf-mexico-hypoxic-zone">low dissolved oxygen levels in water</a> at certain times of year, may influence a fish’s mercury levels.</p>
<p>The strength of this method is that it provides information for individual fish, which matters just as it does for humans. Different individual fish have varying abilities to catch prey and avoid or tolerate stress, all of which can affect their growth and exposure to mercury. </p>
<p>And having information about mercury exposure for all ages of a single fish can help decrease the need to collect large samples of many fish across all ages, which is how scientists traditionally have assessed how fishes’ exposure changes over their lifetimes.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1179802840728051712"}"></div></p>
<p>This new method may also help us understand how climate change is affecting mercury exposure.</p>
<p>As water temperatures rise, rivers, lakes, estuaries and oceans are losing some of their dissolved oxygen. This process, known as <a href="https://scripps.ucsd.edu/research/climate-change-resources/faq-ocean-deoxygenation">deoxygenation</a>, is a critical stressor for aquatic life. </p>
<p>When oxygen in a pond or bay falls below 2 milligrams per liter, compared with normal levels of 5 to 8 milligrams per liter, that water body is said to be hypoxic – and hypoxic conditions can be associated with elevated concentrations of methylmercury. This loss of oxygen is exacerbated by <a href="https://oceanservice.noaa.gov/hazards/hypoxia/#">nutrient pollution</a> – for example, from urban or agricultural runoff. But it can also occur in the open oceans, far from continents, due to warming.</p>
<p>Increasing hypoxia could negate <a href="https://www.mercuryconvention.org/en">recent global efforts to reduce mercury emissions</a> by making the mercury that is already in lakes and oceans more available for uptake into fish. However, fish response to hypoxia can vary by individual and by species. Our current research, sponsored by the National Science Foundation, is exploring how fish eye lenses, together with otoliths, can help us disentangle exposure to mercury from diet and hypoxia. </p>
<p>Increasingly, scientists are recognizing that various body parts of organisms function as archives of the past. For us, eye lenses and otoliths serve as key means to understand the secret lives of individual fish.</p><img src="https://counter.theconversation.com/content/196721/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roxanne Razavi receives funding from the U.S. National Science Foundation. </span></em></p><p class="fine-print"><em><span>Hadis Miraly is supported by funding from the U.S. National Science Foundation. </span></em></p><p class="fine-print"><em><span>Karin Limburg receives funding from the U.S. National Science Foundation, which sponsored this research. </span></em></p>A new study shows that a time stamp can be put on mercury that accumulates in fish eyes, offering a window into their lifetime exposure.Roxanne Razavi, Assistant Professor of Environmental Biology, State University of New York College of Environmental Science and ForestryHadis Miraly, PhD Candidate in Environmental Biology, State University of New York College of Environmental Science and ForestryKarin Limburg, Distinguished Professor of Environmental Biology, State University of New York College of Environmental Science and ForestryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1913252022-09-29T02:02:45Z2022-09-29T02:02:45ZHeavy mercury contamination at Maya sites reveals a deep historic legacy<figure><img src="https://images.theconversation.com/files/486682/original/file-20220927-22-b7es39.jpeg?ixlib=rb-1.1.0&rect=17%2C8%2C5973%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Mercury is a toxic heavy metal. When leached into the natural environment, it accumulates and <a href="https://www.nationalgeographic.org/activity/biomagnification-and-bioaccumulation/">builds up</a> through food chains, ultimately threatening human health and ecosystems. </p>
<p>In the last century, human activities have increased atmospheric mercury concentrations by 300-500% <a href="https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi-2IXCu7P6AhViQ_EDHYViCQYQFnoECAgQAQ&url=https%3A%2F%2Fwedocs.unep.org%2Fbitstream%2Fhandle%2F20.500.11822%2F25462%2FGMA%25202018-ReviewDraft_250518_CLEAN_SEC.pdf%3Fsequence%3D1%26isAllowed%3Dy&usg=AOvVaw1rvXANIdBNzIPH69buH2US">above natural levels</a>. </p>
<p>However, in some parts of the world, humans have been modifying the mercury cycle for thousands of years. This anthropogenic (human-caused) mercury use has led to mercury entering places globally it wouldn’t otherwise be found, such as <a href="https://pubs.acs.org/doi/abs/10.1021/es9030408">in lakes or soils</a> in remote locations.</p>
<p>One region with an especially long (but poorly documented) history of mercury use is Mexico and Central America. Early Mesoamerican societies such as the Olmec had been mining and using mercury in southern Mexico as early as 2000 BCE.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=814&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=814&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=814&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1023&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1023&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486997/original/file-20220928-12-9igmxa.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1023&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map of Mexico and Central America shows sites where liquid mercury has been found, known geological sources, and Maya sites with elevated soil mercury.</span>
<span class="attribution"><span class="source">https://www.frontiersin.org/articles/10.3389/fenvs.2022.986119/full</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In our research, <a href="https://doi.org/10.3389/fenvs.2022.986119">published</a> in Frontiers in Environmental Science, we review the ways the Maya used mercury, the mystery of how they sourced it, and the environmental legacy of past mercury use.</p>
<p>Our present mercury problem has a deep legacy. Understanding its origins will also help us understand the trajectory of humanity’s fascination with, use of – and abuse of – this mercurial element.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-poisonous-mercury-gets-from-coal-fired-power-plants-into-the-fish-you-eat-176434">How poisonous mercury gets from coal-fired power plants into the fish you eat</a>
</strong>
</em>
</p>
<hr>
<h2>Cultural and creative importance</h2>
<p>Archaeologists have been finding mercury at archaeological sites in Mexico and Central America for more than a century.</p>
<p>The most common form reported is cinnabar (mercury sulfide, or HgS), a bright red mineral used extensively by the ancient Maya for decoration, craft, and ritual purposes such as burials and in tombs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486944/original/file-20220927-22-rb0u29.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Maya used cinnabar in burials, identifiable by its distinct red colour.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cinnabar_for_Burial_of_Kinich_Hanab_Pakal,_Ruler_of_Palenque,_615-683_AD.jpg">Maya Gallery, National Museum of Anthropology/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>It has been far less common to find liquid (elemental) mercury. There are only seven occurrences of liquid mercury at Mesoamerican sites that we are aware of. </p>
<p>But it’s feasible there may have been many more – and that it’s simply invisible in today’s archaeological record. Liquid mercury from 1,000 or more years ago could have evaporated or oozed away into the environment through time.</p>
<h2>Exceeding toxic levels</h2>
<p>Most Maya settlements were great distances from known mercury sources located in Mexico and Honduras, and perhaps Guatemala and Belize. This means the production, trade, and use of mercury would have been highly valuable and logistically challenging – especially for managing toxic liquid mercury! </p>
<p>Over the past two decades, scientists working on Maya archaeological projects have tested artefacts, soils, and sediments for their chemical properties, including for mercury, to better understand past human activities. </p>
<p>They test soils and former Maya areas excavated from far below today’s ground surface, which tell us about mercury levels during the Maya’s time.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486905/original/file-20220927-14-oe03bu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rob Griffin sampling sediments for mercury near the bottom of the Corriental reservoir in Tikal, Guatemala.</span>
<span class="attribution"><span class="source">Nick Dunning</span></span>
</figcaption>
</figure>
<p>Combined data from these tests show most Maya sites have some amount of mercury enrichment in buried soils. Specifically, seven out of ten sites were found to have mercury levels that equal or exceed modern benchmarks for environmental toxicity. </p>
<p>Locations with elevated mercury are typically areas the Maya occupied, including domestic patios, dating to the Late Classic (600-900 CE). Mercury also made its way into some drinking water sources including central reservoirs at Tikal.</p>
<p>While the appealing red cinnabar ore is the likely culprit of mercury pollution, the equally appealing and shimmering liquid mercury is another possible source of persistent pollution in some locations, such as Lamanai in modern-day Belize.</p>
<figure class="align-center ">
<img alt="Droplets of silvery liquid metal" src="https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486703/original/file-20220927-26-5gr5e1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mercury, also known as quicksilver, occurs naturally and is the only metallic element that stays liquid at room temperature.</span>
<span class="attribution"><span class="source">MarcelClemens/Shutterstock</span></span>
</figcaption>
</figure>
<p>At more complex sites, elevated mercury levels may be the result of both modern and ancient inputs. For example, it’s not clear if the mercury detected at the island Maya settlement of Marco Gonzalez (also in Belize) is from ancient or modern times. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/belize-shows-how-local-engagement-is-key-in-repatriating-cultural-artifacts-from-abroad-171363">Belize shows how local engagement is key in repatriating cultural artifacts from abroad</a>
</strong>
</em>
</p>
<hr>
<h2>Looming questions</h2>
<p>Our work reveals a rich history of mercury use by the Maya and challenges the idea that pre-industrial societies didn’t have noteworthy impacts on their environments.</p>
<p>But there is much we still don’t know. Where and how did the Maya obtain mercury? Who mined it, traded it, and transported it by foot over hundreds of kilometres across present-day Central America? </p>
<p>Then there’s the question of whether the Maya were affected by mercury exposure. The next step will be for geochemists and archaeologists to track down the source of mercury at key sites and, if possible, scrutinise archaeological and human remains for signs of past mercury exposure.</p>
<p>We also need to find out what forms mercury takes in the environment today, so we can better understand where it came from, and provide guidance on what precautions (if any) need to be taken when working with legacy mercury. </p>
<p>Finding clues on early mercury use is crucial to understanding the interaction between legacy mercury and current mercury contamination in the environment today. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-conflict-collapse-how-drought-destabilised-the-last-major-precolonial-mayan-city-187165">Climate, conflict, collapse: how drought destabilised the last major precolonial Mayan city</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/191325/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duncan Cook receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Nicholas Dunning works for the University of Cincinnati. His work related to Mercury in the Maya Lowlands has been funded by grants from the US National Science Foundation and the Wenner-Gren Foundation.. </span></em></p><p class="fine-print"><em><span>Sheryl Luzzadder-Beach works for the University of Texas at Austin, and received funding for this research from this university, the US National Science Foundation, and the National Geographic Society. She is affiliated with the American Association of Geographers. </span></em></p><p class="fine-print"><em><span>Simon Turner received funding for this mercury research from The Leverhulme Trust.</span></em></p><p class="fine-print"><em><span>Timothy Beach works for the University of Texas at Austin and worked for Georgetown University for 21 years, and received funding for this research from these universities, the US National Science Foundation, and the National Geographic Society. </span></em></p>The Maya would have had to obtain mercury from far locations, transporting it by foot hundreds of kilometres across present-day Central America.Duncan Cook, Associate Professor in Geography, Australian Catholic UniversityNicholas Dunning, Professor, University of Cincinnati Sheryl Luzzadder-Beach, Centennial Professor of Geography and the Environment, The University of Texas at AustinSimon Turner, Senior Research Fellow in Geography, UCLTimothy Beach, Professor, The University of Texas at AustinLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1911522022-09-27T13:11:58Z2022-09-27T13:11:58ZNigeria’s sacred Osun River supports millions of people - but pollution is making it unsafe<figure><img src="https://images.theconversation.com/files/486262/original/file-20220923-9077-t1qt1j.jpg?ixlib=rb-1.1.0&rect=16%2C5%2C3578%2C2382&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Osun River has become turbid and unsafe for consumption - threatening its cultural and biodiversity significance. Photo by: Stefan Heunis/AFP via Getty Images.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-throws-a-sacrificial-chicken-into-the-sacred-river-news-photo/1018606984?adppopup=true">from www,gettyimages.com</a></span></figcaption></figure><p><em>Pollution has become a worrying threat to Nigeria’s Osun River. The river supports millions of people who rely on the water for agriculture as well as industries. It is also an integral part of Nigeria’s treasured Osun-Osogbo sacred grove, a UNESCO world heritage site. Emmanuel O. Akindele unpacks what’s causing the pollution, what harm it’s causing and what must change to preserve the river’s biodiversity.</em> </p>
<h2>How important is the Osun River to Nigeria?</h2>
<p>The Osun River is one of the major rivers in southern Nigeria, <a href="https://link.springer.com/article/10.1007/s11356-020-08763-8">draining into the Gulf of Guinea</a>. The river takes its source from Ekiti State. But it’s culturally linked to the ancient city of <a href="https://core.ac.uk/download/pdf/236410037.pdf">Osogbo</a>. A stretch of the river that flows by a sacred grove in the ancient town of Osogbo has been designated a <a href="https://whc.unesco.org/en/list/1118/">UNESCO World Heritage Site</a> due to its <a href="https://whc.unesco.org/en/list/1118">cultural</a> significance. It is one of two such designated sites in <a href="https://whc.unesco.org/en/statesparties/ng">Nigeria</a>. </p>
<p>The river provides a wide range of cultural ecosystem services such as <a href="https://afribary.com/works/assessment-of-the-ecotourism-potentials-of-osun-osogbo-world-heritage-site-osun-state-nigeria">natural scenes</a> for eco-tourists and the site for filming Nollywood movies. A large number of foreign tourists <a href="https://www.academia.edu/52361771/HARNESSING_CULTURAL_HERITAGE_FOR_TOURISM_DEVELOPMENT_IN_NIGERIA_A_STUDY_OF_THE_OSUN_OSOGBO_SACRED_GROVE_AND_FESTIVAL">visit</a> the river each year. The visits are either to pay homage to the river goddess (Osun) or to join others in celebrating the <a href="https://www.vanguardngr.com/2022/08/2022-osun-festival-begins-with-spiritual-cleansing-of-roads/">annual Osun festival</a>. </p>
<p>The river also has enormous environmental value given its rich <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aje.12482">biodiversity</a>. It supports <a href="https://www.tandfonline.com/doi/abs/10.1080/21658005.2017.1357290?journalCode=tzec20">plankton</a>, <a href="https://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77442007000200034">snakes</a> and <a href="https://www.frim.gov.my/v1/JTFSOnline/jtfs/v26n1/5-15.pdf">endangered plants</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A flowing river bordered by dense forest." src="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Osun River is one of the last remnants of primary high forest in southern Nigeria - UNESCO World Heritage Site. But pollution is threatening the river.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/osun-river-osun-osogbo-sacred-grove-osogbo-osun-royalty-free-image/1141985549?adppopup=true">from www.gettyimages.com</a></span>
</figcaption>
</figure>
<p>Along its whole course, the Osun River also plays a <a href="https://www.tandfonline.com/doi/pdf/10.1080/16583655.2019.1567899">critical part</a> in supporting the livelihoods of people. In many areas of Osogbo and Osun State, it provides irrigation for nearby farmlands. A significant number of abattoirs are also situated close to the river bank along several stretches of its course. </p>
<p>The Osun River flows through other human settlements in southwest Nigeria as well as the historic city of Osogbo.</p>
<h2>What are the main sources of the pollution?</h2>
<p>Plastic pollution is the main one. My research has shown that some <a href="https://theconversation.com/nigerian-river-snails-carry-more-microplastics-than-rhine-snails-126622">aquatic snails</a> and <a href="https://theconversation.com/why-microplastics-found-in-nigerias-freshwaters-raise-a-red-flag-147432">insects</a> of the river carry microplastic pollutants. Plastic pollution is a common phenomenon in many inland waters of Nigeria. </p>
<p>Heavy metals also pollute the river. Heavy metals like gold, mercury and cadmium <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144270/">occur naturally</a> in the Earth’s crust. But they can also be introduced through domestic and industrial wastes, or atmospheric sources. Heavy metals can be <a href="https://www.sciencedirect.com/science/article/pii/S2405844020315346">amplified</a> by human activities like waste deposition or mining. Mining loosens heavy metals buried in the earth, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129257/">adding more of them</a> to water. </p>
<p>Artisanal gold mining within the catchments of the Osun River, especially around the Ijesha land area of Osun State, have further worsened the ecological condition of the river and made the water <a href="https://www.premiumtimesng.com/news/top-news/548204-osun-osogbo-festival-govt-warns-devotees-tourists-against-drinking-from-river.html">unsafe</a> for human use. </p>
<p>The impact of illegal gold mining on the river cannot be over-emphasised. First, the impacts have been felt on the river’s water quality, which has deteriorated. This has grave implications for its <a href="http://medcraveonline.com/BIJ/water-pollution-and-aquatic-biodiversity.html">biological diversity</a>.</p>
<p>Aside from the introduction of toxicants, the river, which was once <a href="https://www.tandfonline.com/doi/abs/10.1080/21658005.2017.1357290?journalCode=tzec20">transparent</a> enough for photosynthetic production, is now very turbid (cloudy) with a characteristic gold colour. At extremely low water transparency, a river’s phytoplankton primary production could be <a href="https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1046&context=oak-lake_research-pubs">threatened</a>, and by implication, its secondary (fish) production could also be threatened. It can also cause fish to die by <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/255660.pdf">blocking</a> their gills and destroying their reproductive sites. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/KMmMsKIVuTk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Osun river pollution. Credit: UrbanAlert,</span></figcaption>
</figure>
<p>Another source of pollution is human-generated <a href="https://www.voanews.com/a/nigeria-s-osun-river-sacred-revered-and-increasingly-toxic/6708178.html">waste</a> that lands up in the river. This is due to <a href="https://theconversation.com/nigerias-plastic-pollution-is-harming-the-environment-steps-to-combat-it-are-overdue-177839">poor waste management practice</a> – a feature common in many urban areas in Nigeria. </p>
<h2>What are the solutions?</h2>
<p>The government must first halt all mining near the river until environmental audits have been conducted, placing urgent human welfare ahead of short-term economic gains. Although the river has already suffered significant harm, it is still possible to halt mining operations so that toxicant concentrations do not keep rising and the river can recuperate from the stress of pollution. </p>
<p>Through natural processes, rivers and streams have the ability to <a href="https://www.sciencedirect.com/science/article/pii/S187802961101022X?via%3Dihub">purify</a> themselves. However, in the instance of the Osun River, this can only happen after the various sources of pollution are stopped. </p>
<p>If further gold mining operations are suggested following an environmental audit of the Osun River, it will be crucial to reroute effluents from all natural waters in the basin. A special reservoir can be constructed in a location far away from where people live and make their living.</p>
<p>A polluted and unsafe environment for plants and animals is a reliable indicator of a similarly unsafe environment for people.</p><img src="https://counter.theconversation.com/content/191152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emmanuel O. Akindele receives funding from the British Ecological Society. </span></em></p>The ability of the Osun River to support biodiversity is being threatened by pollution and can only be rescued if the contamination ends.Emmanuel O. Akindele, Senior Lecturer, Obafemi Awolowo UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1766822022-03-23T03:29:04Z2022-03-23T03:29:04ZHow much tuna can I eat a week before I need to worry about mercury?<figure><img src="https://images.theconversation.com/files/444960/original/file-20220208-23-mcta7k.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5568%2C3692&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For as little as A$1 a tin, canned tuna is an excellent, affordable source of protein, polyunsaturated fats and other nutrients. A tin of tuna is significantly cheaper than many types of fresh meat or fish. </p>
<p>Sounds good, but how much can you eat before you need to worry about mercury?</p>
<p>According to <a href="https://www.foodstandards.gov.au/consumer/chemicals/mercury/Documents/Mercury%20in%20Fish%20brochure%20Dec%202020%20Final.pdf">Food Standards Australia New Zealand</a>: </p>
<blockquote>
<p>It is safe for everyone (including pregnant women) to consume canned tuna as part of their fish intake. </p>
<p>Canned tuna generally has lower levels of mercury than tuna fillets because smaller tuna species are used and the tuna are generally younger when caught.</p>
</blockquote>
<p>But how many tins a week? </p>
<p><a href="https://www.abc.net.au/catalyst/mercury/11016258">Lab tests</a> we did for the ABC TV science program Catalyst in 2015 suggest – depending on your body weight and the exact brand of tuna you buy – you could eat anywhere between 25 and 35 small tins (95g each) of tuna a week before you hit maximum mercury limits.</p>
<p>That’s a level even the most keen tuna-lover would be hard pressed to consume.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-gold-industry-stamped-out-mercury-pollution-now-its-coals-turn-151202">Australia’s gold industry stamped out mercury pollution — now it's coal's turn</a>
</strong>
</em>
</p>
<hr>
<h2>How does mercury end up in fish anyway?</h2>
<p>Mercury is naturally present in our environment but can biomagnify to relatively high concentrations in fish – particularly predatory fish. </p>
<p>In other words, it builds up as smaller fish get eaten by middle-sized fish, which get eaten by large fish, which get eaten by us. So the bigger the fish, the higher the likely mercury content.</p>
<p>Most forms of mercury are potentially very toxic to humans. But to make matters worse, a substantial proportion of mercury in fish is present as methylmercury – a potent neurotoxin formed by bacteria in waters and sediments. </p>
<p>Although mercury pollution has increased since industrialisation, accumulation of methylmercury in animals is a completely natural phenomenon.</p>
<p>Even fish caught from the middle of the ocean, far from any polluting sources, will contain methylmercury.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450287/original/file-20220307-84943-1py9m1z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tinned tuna is cheap, tasty and nutritious.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Tuna in Australian cupboards is likely smaller species</h2>
<p>Over the years, some scientists have <a href="https://www.tandfonline.com/doi/abs/10.1080/23308249.2017.1362370?journalCode=brfs21">raised concerns</a> about high concentrations of mercury in canned tuna. </p>
<p>Mercury concentrations are higher in predatory fish such as tuna and generally increase with age and size. So this concern has largely been associated with the use of tuna species such as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0013935103002202?via%3Dihub">albacore and larger tuna specimens</a>.</p>
<p>Skipjack and yellowfin are the main tuna species listed as ingredients in canned tuna in brands sold at Australian supermarkets. </p>
<p>Skipjack are the smallest of the major tuna species, while yellowfin are larger.</p>
<p>So, the fact the canned tuna in Australian cupboards is likely to contain smaller species is already a bonus when it comes to reducing mercury risk. </p>
<p>But let’s drill down to the details.</p>
<h2>How much mercury can we have?</h2>
<p>According to <a href="https://www.foodstandards.gov.au/publications/Documents/mercury%20in%20fish%20-%20further%20info.pdf">Food Standards Australia New Zealand</a>:</p>
<blockquote>
<p>Two separate maximum levels are imposed for fish ― a level of 1.0 mg mercury/kg for the fish that are known to contain high levels of mercury (such as swordfish, southern bluefin tuna, barramundi, ling, orange roughy, rays and shark) and a level of 0.5 mg/kg for all other species of fish.</p>
</blockquote>
<p>However, whether mercury is harmful or not also depends on the amount of fish you eat and how often. After all, it is the dose that makes the poison.</p>
<p>Based on <a href="https://www.wam.go.jp/wamappl/bb11gs20.nsf/0/49256fe9001b533f49256ef4002474e9/$FILE/2-1_1.pdf">international guidelines</a>, Food Standards Australia New Zealand also provides recommended safe limits for dietary intake. In other words, how much mercury you can safely have from <em>all</em> food sources (not just fish).</p>
<p>This limit is known as the “provisional tolerable weekly intake” or PTWI.</p>
<p>The maximum dose of mercury set for the general population is <a href="https://www.foodstandards.gov.au/publications/Pages/Mercury-in-fish---background-to-the-mercury-in-fish-advisory-statement.aspx">3.3 micrograms per kilogram of body weight per week</a>. 1,000 micrograms (µg) is 1 milligram (mg).(The guidelines assume all mercury in fish is present as the more harmful methylmercury as a worst case scenario).</p>
<p>The dose for pregnant women is approximately half this value – <a href="https://www.foodstandards.gov.au/publications/Pages/Mercury-in-fish---background-to-the-mercury-in-fish-advisory-statement.aspx">1.6 micrograms per kilogram of body weight per week)</a>. </p>
<p>Pregnant women are advised to limit their fish intake because of placental transfer of mercury to the unborn foetus and the effect of mercury on neural development.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450289/original/file-20220307-25900-1outlwh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Whether mercury is harmful or not also depends on the amount of fish you eat and how often.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Testing three tins</h2>
<p>Our laboratory is well equipped to measure mercury concentrations in fish. As part of the <a href="https://www.abc.net.au/catalyst/mercury/11016258">Catalyst</a> program in 2015, we analysed mercury concentrations in Australian fish including three tins of canned tuna purchased from the supermarket.</p>
<p>Given the very low sample numbers, our data is just a snapshot of mercury concentrations. More research is clearly needed.</p>
<p>We found none of the canned tuna brands exceeded the safe consumption levels for mercury of 0.5 milligrams of mercury a kilogram. All three tins had slightly different levels of mercury but even the “worst” one wasn’t that bad. </p>
<p>You would have to eat around 25 tins (at 95g a tin) of it a week before you hit the maximum tolerable intake of mercury. For pregnant people (or people trying to get pregnant), the limit would be around 12 tins (at 95g a tin) a week.</p>
<p>It is unlikely many consumers will reach these limits.</p>
<h2>But watch out for other species of fish</h2>
<p>Some Australian fresh fish can contain higher mercury concentrations than canned tuna.</p>
<p>Food Standards Australia New Zealand <a href="https://www.foodstandards.gov.au/consumer/chemicals/mercury/Pages/default.aspx">recommends</a> that, for orange roughy (also known as deep sea perch) or catfish, people should limit themselves to <a href="https://www.foodstandards.gov.au/publications/Documents/mercury%20in%20fish%20-%20further%20info.pdf">one 150 gram serving a week</a> with no other fish that week. For shark (flake) or swordfish/broadbill and marlin, the <a href="https://www.foodstandards.gov.au/consumer/chemicals/mercury/Pages/default.aspx">limit</a> is one serving a fortnight.</p><img src="https://counter.theconversation.com/content/176682/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A tin of tuna is significantly cheaper than many types of fresh meat or fish. But how much can you eat before you need to worry about mercury?Simon Apte, Senior Senior Principal Research Scientist, CSIROChad Jarolimek, Senior Experimental Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1762262022-02-24T13:53:06Z2022-02-24T13:53:06ZPlastic pollution is a global problem – here’s how to design an effective treaty to curb it<figure><img src="https://images.theconversation.com/files/447907/original/file-20220222-17-5zchyn.jpg?ixlib=rb-1.1.0&rect=14%2C29%2C4905%2C3245&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Plastic trash floating on the Buriganga river in Dhaka, Bangladesh,
Jan. 21, 2020</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/man-paddles-on-a-boat-as-plastic-bags-float-on-the-water-news-photo/1195130532">Munir Uz Zaman/AFP via Getty Images</a></span></figcaption></figure><p>Plastic pollution is accumulating worldwide, on land and in the oceans. According to one widely cited estimate, by 2025, 100 million to 250 million metric tons of plastic waste could <a href="http://dx.doi.org/10.1126/science.1260352">enter the ocean each year</a>. Another study commissioned by the World Economic Forum projects that without changes to current practices, there may be <a href="https://www3.weforum.org/docs/WEF_The_New_Plastics_Economy.pdf">more plastic by weight than fish in the ocean by 2050</a>. </p>
<p>On March 2, 2022, representatives from 175 nations around the world took a historic step toward ending that pollution. The <a href="https://www.unep.org/news-and-stories/press-release/historic-day-campaign-beat-plastic-pollution-nations-commit-develop">United Nations Environment Assembly voted</a> to task a committee with forging a legally binding global treaty on plastic pollution by 2024. U.N. Environment Program Executive Director Inger Andersen described it as “an insurance policy for this generation and future ones, so they may live with plastic and not be doomed by it.” </p>
<p>I am a <a href="https://scholar.google.com/citations?user=nvnsqIoAAAAJ&hl=en">legal scholar</a> and have studied questions related to food, animal welfare and environmental law. My forthcoming book, “<a href="https://www.cambridge.org/core/books/our-plastic-problem-and-how-to-solve-it/CAD4AF039D41B2CD6B66BF3B8DF57BF0">Our Plastic Problem and How to Solve It</a>,” explores legislation and policies to address this global “<a href="https://theconversation.com/were-failing-to-solve-the-worlds-wicked-problems-heres-a-better-approach-64949">wicked problem</a>.” </p>
<p>I believe plastic pollution requires a local, national and global response. While acting together on a world scale will be challenging, lessons from some other environmental treaties suggest features that can improve an agreement’s chances of success. </p>
<h2>A pervasive problem</h2>
<p>Scientists have discovered plastic in some of the most remote parts of the globe, from <a href="https://doi.org/10.1016/j.envres.2022.112741">polar ice</a> to <a href="https://www.usatoday.com/in-depth/tech/science/2018/09/06/see-how-great-pacific-garbage-patch-feeds-off-our-throwaway-culture/1133734002/">Texas-sized gyres</a> in the middle of the ocean. Plastic can enter the environment from a myriad of sources, ranging from <a href="https://doi.org/10.1002/etc.3408">laundry wastewater</a> to illegal dumping, waste incineration and accidental spills. </p>
<p>Plastic never completely degrades. Instead, it breaks down into tiny particles and fibers that are easily ingested by <a href="https://theconversation.com/hundreds-of-fish-species-including-many-that-humans-eat-are-consuming-plastic-154634">fish</a>, <a href="https://theconversation.com/all-you-can-eat-landfill-buffet-spells-trouble-for-birds-92562">birds</a> and <a href="https://doi.org/10.1111/gcb.14020">land animals</a>. Larger plastic pieces can transport <a href="https://doi.org/10.3389/fevo.2021.629756">invasive species</a> and accumulate in freshwater and coastal environments, altering ecosystem functions. </p>
<p>A 2021 report by the <a href="https://www.nap.edu/read/26132/chapter/2">National Academies of Sciences, Engineering and Medicine</a> on ocean plastic pollution concluded that “[w]ithout modifications to current practices … plastics will continue to accumulate in the environment, particularly the ocean, with adverse consequences for ecosystems and society.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic on quantities of plastic waste" src="https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=826&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=826&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=826&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1038&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1038&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447910/original/file-20220222-13-jy397x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1038&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plastic pollution by the numbers.</span>
<span class="attribution"><a class="source" href="https://ocean.si.edu/conservation/pollution/plastic-pollution-infographic">University of Georgia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>National policies are not enough</h2>
<p>To address this problem, the U.S. has focused on <a href="https://www.washingtonpost.com/climate-solutions/2021/11/15/epa-national-recycling-strategy-plastics/">waste management and recycling</a> rather than regulating plastic producers and businesses that use plastic in their products. Failing to address the sources means that policies have limited impact. That’s especially true since the U.S. generates 37.5 million tons of plastic yearly, but <a href="https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/plastics-material-specific-data">only recycles about 9% of it</a>. </p>
<p>Some countries, such as France and Kenya, have <a href="https://www.globalcitizen.org/en/content/plastic-bans-around-the-world/">banned single-use plastics</a>. Others, like Germany, have mandated <a href="https://www.dw.com/en/how-does-germanys-bottle-deposit-scheme-work/a-50923039">plastic bottle deposit schemes</a>. Canada has <a href="https://mcmillan.ca/insights/plan-for-the-banplastics-classified-as-toxic-substanceunder-canadian-environmental-protection-act/">classified manufactured plastic items as toxic</a>, which gives its national government broad power to regulate them. </p>
<p>In my view, however, these efforts too will fall short if countries producing and using the most plastic do not adopt policies across its life cycle.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1483400377064210434"}"></div></p>
<h2>Growing consensus</h2>
<p>Plastic pollution crosses boundaries, so countries need to work together to curb it. But existing treaties such as the 1989 <a href="http://www.basel.int/TheConvention/Overview/tabid/1271/Default.aspx">Basel Convention</a>, which governs international shipment of hazardous wastes, and the 1982 <a href="https://www.un.org/depts/los/convention_agreements/convention_overview_convention.htm">U.N. Convention on the Law of the Sea</a> offer little leverage, for several reasons. </p>
<p>First, these treaties were not designed specifically to address plastic. Second, the largest plastic polluters – <a href="https://grist.org/climate/ocean-plastic-which-countries-are-responsible/">notably, the U.S.</a> – have not joined these agreements. Alternative international approaches such as the <a href="https://www.iucn.org/news/marine-and-polar/201905/iucn-endorses-global-oceans-plastics-charter">Ocean Plastics Charter</a>, which encourages governments and global and regional businesses to design plastic products for reuse and recycling, are voluntary and nonbinding. </p>
<p>Fortunately, many world and business leaders now support a uniform, standardized and coordinated global approach to managing and eliminating plastic waste in the form of a treaty. </p>
<p>The American Chemistry Council, an industry trade group, <a href="https://www.americanchemistry.com/chemistry-in-america/news-trends/press-release/2021/plastic-makers-support-global-agreement-to-eliminate-plastic-waste-welcome-us-leadership">supports an agreement</a> that will accelerate a transition to a more <a href="https://www.weforum.org/topics/circular-economy">circular economy</a> that promotes waste reduction and reuse by focusing on waste collection, product design and recycling technology. <a href="https://www.plasticmakers.org/files/f844022f219e9f85633604e9d4fb6c1b2dcd2e35.pdf">America’s Plastic Makers</a> and the <a href="https://icca-chem.org/focus/plastics/plastic-makers-call-for-global-agreement-among-nations-to-eliminate-plastic-waste/">International Council of Chemical Associations</a> have also made public statements supporting a global agreement to establish “a targeted goal to ensure access to proper waste management and eliminate leakage of plastic into the ocean.” </p>
<p>However, these organizations maintain that plastic products can help reduce energy use and greenhouse gas emissions – for example, by enabling automakers to build lighter cars – and are likely to oppose an agreement that limits plastic production. As I see it, this makes leadership and action by governments critical. </p>
<p>The Biden administration also has <a href="https://www.eenews.net/articles/u-s-to-back-global-treaty-aimed-at-curbing-plastic-pollution/">stated its support for a treaty</a> and is sending Secretary of State Antony Blinken to the Nairobi meeting. On Feb. 11, 2022, the White House released a <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2022/02/11/joint-statement-between-the-united-states-and-france-on-the-one-ocean-summit-in-france/">joint statement</a> with France that expressed support for negotiating “a global agreement to address the full life cycle of plastics and promote a circular economy.”</p>
<p><a href="https://eia-international.org/wp-content/uploads/EIA-Report-Analysis-2021-Comparison_Resolutions_Plastic_UNEA-5.2.pdf">Early treaty drafts</a> outline two competing approaches. One seeks to reduce plastic throughout its life cycle, from production to disposal, a strategy that would probably include methods such as banning or phasing out single-use plastic products. </p>
<p>A contrasting approach focuses on eliminating plastic waste through innovation and design – for example, by spending more on waste collection, recycling and development of <a href="https://theconversation.com/bio-based-plastics-can-reduce-waste-but-only-if-we-invest-in-both-making-and-getting-rid-of-them-98282">environmentally benign plastics</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/X4uefUtvLpc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Some harmful impacts of plastic waste become more intense as the plastic breaks down into smaller and smaller fragments.</span></figcaption>
</figure>
<h2>Elements of an effective treaty</h2>
<p>Countries have come together to solve environmental problems before. The global community has successfully addressed <a href="https://www.state.gov/key-topics-office-of-environmental-quality-and-transboundary-issues/convention-on-long-range-transboundary-air-pollution/">acid rain</a>, <a href="https://www.state.gov/key-topics-office-of-environmental-quality-and-transboundary-issues/the-montreal-protocol-on-substances-that-deplete-the-ozone-layer/">stratospheric ozone depletion</a> and <a href="https://www.epa.gov/international-cooperation/minamata-convention-mercury">mercury contamination</a> through international treaties. These agreements, which include the U.S., offer strategies for a plastics treaty.</p>
<p><a href="https://doi.org/10.1086/676037">The Montreal Protocol</a>, for example, required countries to report their production and consumption of ozone-depleting substances so that countries could hold each other accountable. As part of <a href="https://doi.org/10.1007/s13280-019-01244-4">the Convention on Long-range Air Pollution</a>, countries agreed to reduce sulfur dioxide emissions, but were allowed to select the method that worked best for them. For the U.S., that involved a system of buying and selling emission allowances that became part of the <a href="https://www.epa.gov/emissions-trading-resources/reducing-power-sector-emissions-under-1990-clean-air-act-amendments">Clean Air Act Amendments of 1990</a>.</p>
<p>Based on these precedents, I see plastic as a good candidate for an international treaty. Like ozone, sulfur and mercury, plastic comes from specific, identifiable human activities that occur across the globe. Many countries contribute, so the problem is transboundary in nature. </p>
<p>In addition to providing a framework for keeping plastic out of the ocean, I believe a plastic pollution treaty should include reduction targets for both producing less plastic and generating less waste that are specific, measurable and achievable. The treaty should be binding but flexible, allowing countries to meet these targets as they choose. </p>
<p>In my view, negotiations should consider the interests of those who experience the <a href="https://theconversation.com/plastic-waste-is-hurting-women-in-developing-countries-but-there-are-ways-to-stop-it-166596">disproportionate impacts</a> of plastic, as well as those who make a living off recycling waste as part of the <a href="https://www.wiego.org/sites/default/files/resources/files/WIEGO_Urban_Informal_Workers_Green_Economy.pdf">informal economy</a>. Finally, an international treaty should promote collaboration and sharing of data, resources and best practices. </p>
<p>Since plastic pollution doesn’t stay in one place, all nations will benefit from finding ways to curb it. </p>
<p><em>This article was updated March 2, 2022, with the international vote to write a plastics treaty.</em></p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/176226/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah J. Morath does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Representatives of 175 countries voted to start developing a global treaty to reduce plastic waste. Treaties addressing mercury, long-range air pollution and ozone depletion offer some lessons.Sarah J. Morath, Associate Professor, Wake Forest UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1764342022-02-15T13:24:07Z2022-02-15T13:24:07ZHow poisonous mercury gets from coal-fired power plants into the fish you eat<figure><img src="https://images.theconversation.com/files/446121/original/file-20220213-17-gt0hty.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C3000%2C2110&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Coal-fired power plants are a source of mercury that people can ingest by eating fish.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/danielle-gross-casts-his-fishing-line-into-the-potomac-news-photo/478998730">Mark Wilson/Getty Images</a></span></figcaption></figure><p>People fishing along the banks of the White River as it winds through Indianapolis sometimes pass by ominous signs warning about eating the fish they catch. </p>
<p><a href="https://extension.wsu.edu/foodsafety/content/risks-of-mercury-in-fish">One of the risks</a> they have faced is mercury poisoning.</p>
<p>Mercury is a neurotoxic metal that can cause irreparable harm to human health – especially the brain development of young children. It is <a href="https://doi.org/10.1289/ehp.7743">tied to lower IQ</a> and results in decreased earning potential, as well as higher health costs. Lost productivity from mercury alone was calculated in 2005 to reach <a href="https://doi.org/10.1289/ehp.7743">almost $9 billion per year</a>. </p>
<p>One way mercury gets into river fish is with the gases that rise up the smokestacks of coal-burning power plants. </p>
<p><iframe id="FW8zH" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/FW8zH/6/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>The Environmental Protection Agency has had a rule since 2012 limiting mercury emissions from coal-fired power plants. But the Trump administration <a href="https://eelp.law.harvard.edu/2019/03/rolling-back-the-mercury-and-air-toxics-standards-proposed-withdrawal-of-appropriate-and-necessary/">stopped enforcing it</a>, <a href="https://www.reuters.com/article/us-usa-epa-coal-mercury/trump-administration-weakens-mercury-rule-for-coal-plants-idUSKCN21Y1IW">arguing that the costs</a> to industry outweighed the health benefit.</p>
<p>Now, the Biden administration is <a href="https://www.epa.gov/newsreleases/epa-reaffirms-scientific-economic-and-legal-underpinnings-limits-toxic-emissions">moving to reassert it</a>.</p>
<p>I study mercury and its sources as a <a href="https://scholar.google.com/citations?user=MEp4948AAAAJ&hl=en">biogeochemist</a> at Indiana University-Purdue University Indianapolis. Before the EPA’s original mercury rule went into effect, my students and I launched a project to track how Indianapolis-area power plants were increasing mercury in the rivers and soil.</p>
<h2>Mercury bioaccumulates in the food chain</h2>
<p>The risks from eating a fish from a river downwind from a coal-burning power plant depends on both the type of fish caught and the age and condition of the person consuming it.</p>
<p>Mercury is a <a href="https://www.usgs.gov/special-topics/water-science-school/science/mercury-contamination-aquatic-environments">bioaccumulative toxin</a>, meaning that it increasingly concentrates in the flesh of organisms as it makes its way up the food chain.</p>
<figure class="align-center ">
<img alt="A person's hands old a smallmouth bass, with the fish's mouth open" src="https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446123/original/file-20220213-87622-e0wm9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mercury accumulates as it moves up the food chain.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/holding-a-smallmouth-bass-royalty-free-image/123084571">doug4537 via Getty Images</a></span>
</figcaption>
</figure>
<p>The mercury emitted from coal-burning power plants falls onto soils and washes into waterways. There, the moderately benign mercury is transformed by bacteria into a toxic organic form called methylmercury.</p>
<p>Each bacterium might contain only one unit of toxic methylmercury, but a worm chewing through sediment and eating 1,000 of those bacteria now contains 1,000 doses of mercury. The catfish that eats the worm then get more doses, and so on up the food chain to humans.</p>
<p>In this way, top-level predator fishes, such as smallmouth bass, walleye, largemouth bass, lake trout and Northern pike, typically contain the highest amounts of mercury in aquatic ecosystems. On average, one of these fish contains enough to make eating only <a href="https://www.epa.gov/fish-tech/epa-fda-fish-advice-technical-information">one serving of them per month dangerous</a> for the developing fetuses of pregnant women and for children.</p>
<h2>How coal plant mercury rains down</h2>
<p>In our study, we wanted to answer a simple question: Did the local coal-burning power plants, known to be <a href="https://www.purdue.edu/discoverypark/energy/assets/pdfs/cctr/outreach/Basics2-Mercury-Mar07.pdf">major emitters of toxic mercury</a>, have an impact on the local environment?</p>
<p>The obvious answer seems to be yes, they do. But in fact, quite a bit of research – and coal industry advertising – noted that mercury is a “<a href="https://doi.org/10.1002/etc.1980">global pollutant</a>” and could not necessarily be traced to a local source. A recurring argument is that mercury deposited on the landscape came from coal-burning power plants <a href="https://doi.org/10.1021/es062707c">in China</a>, so why regulate local emissions if others were still burning coal?</p>
<p>That justification was based on the unique chemistry of this element. It is the only metal that is liquid at room temperature, and when heated just to a moderate level, will evaporate into mercury vapor. Thus, when coal is burned in a power plant, the mercury that is present in it is released through the smokestacks as a gas and dilutes as it travels. Low levels of mercury also <a href="https://www.epa.gov/international-cooperation/mercury-emissions-global-context">occur naturally</a>.</p>
<p>Although this argument was technically true, we found it obscured the bigger picture.</p>
<figure class="align-center ">
<img alt="A view of the river with a bridge and the city in the background." src="https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446383/original/file-20220214-19-t52yt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People sometimes fish along the White River where it flows through Indianapolis.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/indianapolis-royalty-free-image/520980871?adppopup=true">alexeys via Getty Images</a></span>
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</figure>
<p>We found the overwhelming source of mercury was within sight of the White River fishermen – a large coal-burning power plant on the edge of the city.</p>
<p>This power plant emitted vaporous mercury at the time, though it has since <a href="https://www.transmissionhub.com/articles/2016/02/indianapolis-powers-harding-street-plant-burns-its-last-coal.html">switched to natural gas</a>. We found that much of the plant’s mercury rapidly reacted with other atmospheric constituents and water vapor to <a href="https://doi.org/10.1007/s11270-010-0703-7">“wash out” over the city</a>. It was <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/gbc.20040">raining down mercury on the landscape</a>.</p>
<h2>Traveling by air and water, miles from the source</h2>
<p>Mercury emitted from the smokestacks of coal-fired power plants can fall from the atmosphere with rain, mist or chemical reactions. Several studies have shown <a href="https://doi.org/10.1016/j.jhazmat.2016.01.026">elevated levels of mercury in soils and plants near power plants</a>, with much of the mercury <a href="https://doi.org/10.1038/srep46545">falling within about 9 miles</a> (15 kilometers) of the smokestack.</p>
<p>When we surveyed hundreds of surface soils ranging from about 1 to 31 miles (2 to 50 km) from the coal-fired power plant, then the single largest emitter of mercury in central Indiana, we were shocked. We found <a href="https://doi.org/10.12952/journal.elementa.000059">a clear “plume” of elevated mercury</a> in Indianapolis, with much higher values near the power plant tailing off to almost background values 31 miles downwind. </p>
<p>The White River flows from the northeast to the southwest through Indianapolis, opposite the wind patterns. When we sampled sediments from most of its course through central Indiana, we found that mercury levels started low well upstream of Indianapolis, but <a href="https://doi.org/10.1007/s11270-010-0703-7">increased substantially</a> as the river flowed through downtown, apparently accumulating deposited mercury along its flow path. </p>
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<p>We also found high levels well downstream of the city. Thus a fisherman out in the countryside, far away from the city, was still <a href="https://doi.org/10.12952/journal.elementa.000059">at significant risk</a> of catching, and eating, high-mercury fish.</p>
<p>The region’s <a href="https://www.in.gov/health/files/Marion_sensitive_fishadvisory.pdf">fish advisories</a> still recommend sharply limiting the amount of fish eaten from the White River. In Indianapolis, for example, pregnant women are advised to <a href="https://www.in.gov/health/files/Marion_sensitive_fishadvisory.pdf">avoid eating some fish</a> from the river altogether.</p>
<h2>Reviving the MATS rule</h2>
<p>The EPA announced the Mercury and Air Toxic Standards rule in 2011 to deal with the exact health risk Indianapolis was facing. </p>
<p>The <a href="https://eelp.law.harvard.edu/2017/09/mercury-and-air-toxics-standards/">rule stipulated</a> that mercury sources had to be sharply reduced. For coal-fired power plants, this meant either installing costly mercury-capturing filters in the smokestacks or converting to another energy source. <a href="https://www.eia.gov/totalenergy/data/monthly/">Many converted to natural gas</a>, which reduces the mercury risk but still contributes to health problems and global warming.</p>
<p>The MATS rule helped tilt the national energy playing field away from coal, until the Trump Administration <a href="https://www.epa.gov/mats/proposed-revised-supplemental-finding-and-results-residual-risk-and-technology-review">attempted to weaken the rule</a> in 2020 to try to bolster the <a href="https://www.eia.gov/todayinenergy/detail.php?id=44155">declining U.S. coal industry</a>. The administration rescinded a “supplemental finding” that determined it is “appropriate and necessary” to regulate mercury from power plants.</p>
<p>On Jan. 31, 2022, the Biden Administration <a href="https://www.epa.gov/stationary-sources-air-pollution/proposed-revocation-2020-reconsideration-and-affirmation">moved to reaffirm that supplemental finding</a> and effectively restore the standards.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=277&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=277&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=277&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=348&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=348&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446071/original/file-20220213-15-aw2lhh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=348&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">More than a quarter of U.S. coal-fired power plants currently operating were scheduled as of 2021 to be retired by 2035.</span>
<span class="attribution"><a class="source" href="https://www.eia.gov/todayinenergy/detail.php?id=50658">EIA</a></span>
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</figure>
<p>Some economists have calculated the net cost of the MATS rule to the U.S. electricity sector to be about <a href="https://www.nera.com/content/dam/nera/publications/archive2/PUB_MATS_Rule_0312.pdf">$9.6 billion per year</a>. This is roughly equal to the earlier estimates of productivity loss from the harm mercury emissions cause.</p>
<p>To a public health expert, this math problem is a no-brainer, and I am pleased to see the rule back in place, protecting the health of generations of future Americans.</p><img src="https://counter.theconversation.com/content/176434/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gabriel Filippelli does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Biden administration is moving to revive mercury limits for coal-fired power plants. A scientist explains mercury’s health risks and the role power plants play.Gabriel Filippelli, Chancellor's Professor of Earth Sciences and Executive Director, Indiana University Environmental Resilience Institute, IUPUILicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658662021-11-12T13:36:08Z2021-11-12T13:36:08ZNeurotoxins in the environment are damaging human brain health – and more frequent fires and floods may make the problem worse<figure><img src="https://images.theconversation.com/files/428985/original/file-20211028-23-ey0fbd.jpg?ixlib=rb-1.1.0&rect=242%2C177%2C3352%2C2204&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildfire smoke contains a mixture of toxic pollutants that can be harmful to both the lungs and the brain. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/california-wildfires-royalty-free-image/1281624333?adppopup=true">Bloomberg Creative/ Bloomberg Creative Photos via Getty Images</a></span></figcaption></figure><p>In the summer of 2021, a toxic, smoky haze stemming from <a href="https://www.nbcnews.com/western-wildfires">Western wildfires</a> wafted across large parts of the United States, while hurricanes wrought extensive flooding in the southern and eastern U.S. Air quality websites such as <a href="https://www.airnow.gov">AirNow</a> warned of <a href="https://www.npr.org/2021/07/21/1018865569/the-western-wildfires-are-affecting-people-3-000-miles-away">hazardous conditions</a> on the U.S. East Coast from Western forest fires 3,000 miles away, with recommendations to stay indoors. </p>
<p>Journalists reported the immediate impact of lives lost and homes and property destroyed, but more insidious dangers escaped notice. Few people realize that these <a href="https://www.npr.org/2021/09/11/1035241392/climate-change-disasters-mental-health-anxiety-eco-grief">climate change-fueled</a> <a href="https://www.washingtonpost.com/world/interactive/2021/cop26-extreme-weather-climate-change-action/">disasters</a> – both fires and <a href="https://doi.org/10.1080/10807030903051309">floods</a> – could <a href="https://doi.org/10.1080/10962247.2017.1401017">adversely affect human health</a> in longer-term ways. </p>
<p>I’m a <a href="https://scholar.google.com/scholar?as_ylo=2017&q=Arnold+Eiser&hl=en&as_sdt=0,39">scientist-author</a> who studies the links between environmental factors and the development of neurological disorders, which is the <a href="https://rowman.com/ISBN/9781538158074/Preserving-Brain-Health-in-a-Toxic-Age-New-Insights-from-Neuroscience-Integrative-Medicine-and-Public-Health">subject of my recent book</a>. My <a href="https://doi.org/10.1016/j.brainres.2017.06.032">research on this topic</a> adds to a growing body of evidence that <a href="https://www.nytimes.com/2019/07/15/climate/flooding-chemicals-health-research.html">more frequent environmental disasters</a> may be raising <a href="https://doi.org/10.1007/s11356-015-4913-9">human exposure to neurotoxins</a>.</p>
<h2>Neurotoxic smoke</h2>
<p>Many scientists have identified links between <a href="https://doi.org/10.1016/j.bj.2018.06.001">air pollution</a> in various forms, including from <a href="https://theconversation.com/breathing-wildfire-smoke-can-affect-the-brain-and-sperm-as-well-as-the-lungs-166548">forest fire smoke</a>, and an increased risk and prevalence of adverse health effects, including brain disorders. </p>
<p>Wildfire smoke is a mixture of <a href="https://health.ny.gov/environmental/outdoors/air/smoke_from_fire">countless noxious chemical compounds</a>. Fires burning <a href="https://www.theguardian.com/world/2021/aug/09/fires-rage-around-the-world-where-are-the-worst-blazes%20and%20Australia">across the warming planet</a> – from California to Greece and Australia – are adding dangerous particulate matter to the atmosphere that includes <a href="https://doi.org/10.5772/intechopen.97204">neurotoxic heavy metals</a> such as mercury, lead, cadmium and manganese nanoparticles. <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">These toxins</a> are an added environmental burden on top of the pollutants emitted by factories, power plants, trucks, automobiles and other sources. </p>
<p>The greatest potential for health problems comes from minuscule particles, smaller than 2.5 microns – or PM 2.5 (for context, the width of a human hair is typically 50 to 70 microns). This is, in part, because <a href="https://doi.org/10.1164/rccm.201903-0635LE">tiny particles are easily inhaled</a>; from the lungs, they enter the bloodstream and circulate widely throughout the body. <a href="https://doi.org/10.3389/fphys.2020.00155">In the brain</a> they may inflame the microglial cells, the brain’s defensive cells, causing harm to neurons instead of protecting them. Studies show that these extremely tiny particles may damage neurons or brain cells by <a href="https://doi.org/10.1016/j.tins.2009.05.009">promoting inflammation</a>. Brain inflammation can lead to conditions <a href="https://doi.org/10.3233/JAD-180631">like dementia</a> and <a href="https://doi.org/10.1097/JOM.0000000000000451">Parkinson’s disease</a>, a movement disorder in adults.</p>
<p>In addition, <a href="https://doi.org/10.1001/jamapediatrics.2018.3101">prenatal</a> and <a href="https://doi.org/10.1097/EDE.0000000000001109">early-life exposure</a> to air pollution has been linked to an increased risk of autism spectrum disorder in children. Research suggests that <a href="https://doi.org/10.1001/jamanetworkopen.2021.7508">air pollution exposure</a> during these critical periods, particularly in the third trimester of pregnancy and the first few months of life, <a href="https://doi.org/10.1515/tnsci-2016-0005">may impair normal neural development</a>. </p>
<h2>Waterborne neurotoxins</h2>
<p>As part of my book research, I investigated potential links between environmental neurotoxins and related health effects in Finland. Seeking unique environmental factors that might underlie the disproportionately high rates of fatal dementia that occurred in Finland in the past decade, I found that <a href="https://doi.org/10.1016/j.brainres.2017.06.032">water pollution</a> – exacerbated by flooding, use of fertilizer and higher water temperatures – may be affecting brain health. </p>
<p>As I reviewed the environmental concerns in Finland, the widespread presence of <a href="https://www.usgs.gov/centers/kswsc/science/cyanobacterial-blue-green-algal-blooms-tastes-odors-and-toxins-0?qt-science_center_objects=0#qt-science_center_objects">blue-green algae in waterways</a> stood out to me. Though it’s commonly called algae, blue-green algae is actually a type of bacteria called cyanobacteria. These toxic microorganisms thrive and proliferate in warm waterways when excessive nutrients, particularly phosphorus from fertilizer runoff, pour into fresh and brackish water. It produces <a href="https://www.epa.gov/cyanohabs/health-effects-cyanotoxins">cyanotoxins</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blue-green algae bloom on surface of lake with trees in the distance." src="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Harmful blooms of blue-green algae on lakes and ponds can be toxic to humans and dogs alike.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sefton-park-lake-in-liverpool-which-has-been-closed-off-news-photo/1228294229?adppopup=true">Peter Byrne/PA Images via Getty Images</a></span>
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<p>One of these cyanotoxins, β-methylamino-L-alanine, or BMAA, is linked to <a href="https://doi.org/10.3389/fnagi.2020.00026">neurodegenerative disorders</a> including amyotrophic lateral sclerosis, or ALS, Parkinson’s disease and Alzheimer’s disease.
In particular I was struck by scientists’ finding high levels of BMAA in <a href="https://doi.org/10.1073/pnas.0914417107">mollusks and fish found in the Baltic Sea</a>, which could potentially play a role in Finland’s high incidence of dementia, as fish is heavily consumed there.</p>
<p>Blue-green algae is found in <a href="https://www.cdc.gov/habs/index.html">rivers, lakes and seas</a>. Its presence is a widespread problem for humans, dogs and wildlife in the U.S. and Canada, as well as around the globe. In 2020, <a href="https://www.bbc.com/news/world-africa-54234396">more than 300 elephants in Botswana died</a> after drinking from water sources contaminated by the cyanobacteria that cause these algal blooms. Blue-green algae is so widely present in Finland that scientists there have developed <a href="https://www.utu.fi/en/news/news/novel-testing-device-will-reveal-whether-water-contains-toxic-blue-green-algae">a quick test to determine whether it is present or not.</a></p>
<h2>Mold neurotoxins</h2>
<p>In Finland, warm, humid air creates the perfect conditions for mold to grow, and water-damaged buildings are particularly susceptible. Some species emit mycotoxins, or mold toxins. Long-term exposure to mycotoxins, even at low levels, can present <a href="https://doi.org/10.1080/00039896.2003.11879142">serious health hazards</a> for both people and animals. </p>
<p>Mold spores are tiny, making them easy to inhale or ingest. Inside the body they can trigger an immune response, leading to chronic inflammation. Ultimately, exposure to these spores may cause <a href="https://doi.org/10.1016/j.shaw.2020.01.003">cognitive impairment</a>, including memory loss, irritability, numbness, tremors and other symptoms. Such a situation is likely to develop after a region has experienced the flooding of residences or workplaces in the weeks after they have been damaged.</p>
<p>Mold toxins, particularly <a href="https://doi.org/10.1002/mnfr.200600137">ochratoxin A</a>, can trigger inflammation that may harm neurons and brain function. It has been <a href="https://doi.org/10.1016/j.jns.2006.06.006">specifically implicated</a> in Parkinson’s disease. </p>
<h2>Reducing risk and a way forward</h2>
<p>Education, greater awareness of environmental health concerns and public action are the best ways to minimize risks from environmental neurotoxins.</p>
<p>By learning to recognize blue-green algae, people may avoid swimming or boating near it and avoid letting their pets near it too. Consumers can advocate for greater environmental monitoring of food and water sources. Exercise that involves sweating can <a href="https://doi.org/10.1155/2017/3676089">help eliminate neurotoxic substances</a>. But before you exercise outdoors, it is prudent to check air quality on an app or website like <a href="https://www.airnow.gov/">AirNow</a>, a partnership of federal, state, local and tribal agencies.</p>
<p>If environmental policies aren’t put into place to mitigate the health risks posed by environmental neurotoxins, <a href="https://doi.org/10.4172/2161-0460.1000249">research suggests</a> that we may continue to experience increases in a variety of neurodegenerative disorders as the toxins rise. Many of these conditions are labeled idiopathic, or lacking a known cause. The neurotoxic connection is rarely considered, and environmental health hazards are <a href="https://doi.org/10.1186/s12909-020-02458-x">often overlooked in American health care</a>. This is in large part because environmental health is rarely taught in medical education, which can lead to a lack of awareness about potential diagnoses related to an environmental illness.</p>
<p>The U.S. Environmental Protection Agency is currently <a href="https://www.epa.gov/system/files/documents/2021-10/draft-policy-assessment-for-the-reconsideration-of-the-pm-naaqs_october-2021_0.pdf">reevaluating</a> air quality standards for particulate matter. A new EPA <a href="https://www.epa.gov/system/files/documents/2021-09/_epaoig_20210929-21-e-0264.pdf">inspector general report</a> calls for a strategic plan to control harmful algal blooms. Ohio, a leading state for public policy initiatives aimed at neurotoxic algal blooms, <a href="https://grist.org/politics/toxic-algae-blooms-are-multiplying-the-government-has-no-plan-to-help">now regulates</a> cyanotoxins in drinking water and advises farmers against adding fertilizer when the ground is saturated or when rain is in the forecast. </p>
<p>Since <a href="https://doi.org/10.1038/s41586-019-1468-9">climate change may be a driver for rising neurotoxins</a>, cutting greenhouse gas emissions and ensuring better environmental stewardship are essential to human health. Achieving this will require strong international and domestic efforts and a wide range of interventions by governments around the world. But all of these efforts must begin with a deeper and more widespread understanding of the profound nature of this problem – which should be a universal, nonpartisan concern. </p>
<p>[<em>Over 115,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-newsletter-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/165866/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold R. Eiser does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Pollution from more frequent floods and wildfires – exacerbated by the warming climate – is threatening human health and poses particular risks to the brain.Arnold R. Eiser, Emeritus Professor of Medicine, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1681592021-10-04T11:40:54Z2021-10-04T11:40:54ZBepiColombo’s first close-up pictures of Mercury’s surface hint at answers to the planet’s secrets<figure><img src="https://images.theconversation.com/files/423350/original/file-20210927-15-1qyik7a.jpg?ixlib=rb-1.1.0&rect=5%2C5%2C3830%2C2151&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of BepiColombo during a swing-by of Mercury</span> <span class="attribution"><span class="source">ESA/ATG medialab</span></span></figcaption></figure><p>The <a href="https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/Mercury_ahead!">BepiColombo spacecraft</a> – a joint project by the European and Japanese space agencies – swung by its destination planet Mercury in the early hours of October 2 2021. Passing within just 200km of the surface of Mercury, it sent back some <a href="https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/BepiColombo_s_first_views_of_Mercury">spectacular pictures</a>.</p>
<p>For those of us who have worked for a decade or more on this mission, there could hardly be a way better to celebrate what would have been the 101st birthday of the mission’s namesake, Italian mathematician and engineer Giuseppe Colombo. His groundbreaking work in this area earned him the title of the <a href="https://www.esa.int/About_Us/ESA_history/Giuseppe_Bepi_Colombo_Grandfather_of_the_fly-by">grandfather</a> of the planetary fly-by technique, now more often termed a “swing-by”.</p>
<p>BepiColombo’s cruise from Earth began in <a href="https://theconversation.com/europe-blasts-off-to-mercury-heres-the-rocket-science-104641">October 2018</a>, and its journey is far from over. It will travel twice around the sun in the time it takes Mercury to orbit the sun three times (around 264 days). This will allow it to rendezvous with the planet for another swing-by on June 23 2022. </p>
<p>After a total of six Mercury swing-bys, the cumulative effect of the planet’s gravity will reduce the spacecraft’s velocity to the point where it can fall into orbit with Mercury around the end of 2025.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The BepiColombo spacecraft showing where the external cameras are mounted" src="https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=215&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=215&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=215&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=270&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=270&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422196/original/file-20210920-22-14erckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=270&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left: the location of the three MCAMs on the Mercury Transfer Module, seen in an exploded view of the spacecraft stack. Right: artist’s impression of the stacked spacecraft.</span>
<span class="attribution"><span class="source">Left: Micro-Cameras & Space Exploration SA. Right: spacecraft: ESA/ATG medialab; Mercury: Nasa/JPL</span></span>
</figcaption>
</figure>
<p>BepiColombo is actually composed of two <a href="https://sci.esa.int/web/bepicolombo">connected</a> spacecraft and a propulsion unit. During its cruise through interplanetary space, the European orbiter (called the “<a href="https://www.cosmos.esa.int/web/bepicolombo/mpo">Mercury Planetary Orbiter</a>” or MPO) is attached on one side to the interplanetary propulsion unit (or “<a href="https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/Mercury_Transfer_Module">Mercury Transfer Module</a>”). On the other, it carries a Japanese orbiter named Mio (or “<a href="https://www.isas.jaxa.jp/en/missions/spacecraft/current/mmo.html">Mercury Magnetospheric Orbiter</a>”), plus a sunshield to prevent Mio from overheating. </p>
<p>This stacked configuration obstructs the openings through which sophisticated visible, infrared and X-ray cameras inside MPO – capable of imaging and analysing Mercury’s surface in great detail – will operate once MPO finally becomes free-flying. In fact, most of BepiColombo’s science instruments will be wholly or partly inoperative until each orbiter is set free, around December 2025.</p>
<h2>Adding the cameras</h2>
<p>Until a relatively late stage in mission planning, it was accepted that BepiColombo would be “flying blind” during its whole cruise from Earth, including during swing-bys – meaning no images would be available until orbit around Mercury had been achieved. </p>
<p>But the level of public interest aroused in 2015 by by images of <a href="https://theconversation.com/rosetta-scientists-unveil-the-source-of-ice-and-dust-jets-on-comet-67p-48122">comet 67P</a> from the Rosetta mission led BepiColombo engineers Kelly Geelen and James Windsor to propose that low-cost lightweight cameras should be added to the spacecraft. </p>
<p>By the end of 2016, it was agreed that three small monitoring cameras – each only 6.5cm in length – would be mounted onto the craft. These would snap planetary pictures during swing-bys. </p>
<p>It was decided to place these cameras on the Mercury Transfer Module, where they would also be able to monitor the deployment of the solar panels that provide the spacecraft with power, the magnetometer boom used for measuring magnetic fields, and the communication antennae.</p>
<figure class="align-center ">
<img alt="One of the monitoring cameras as used on BepiColombo" src="https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=263&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=263&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=263&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=330&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=330&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422419/original/file-20210921-17-fjmmav.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=330&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Extremely small and light monitoring cameras carry out a range of functions on a spacecraft such as BepiColombo.</span>
<span class="attribution"><span class="source">Micro-Cameras & Space Exploration SA.</span></span>
</figcaption>
</figure>
<h2>What Bepi saw</h2>
<p>During BepiColombo’s first Mercury swing-by, the fields of view of monitoring cameras two and three tracked across the planet. Camera three showed us part of the southern hemisphere, beginning with a view of sunrise over <a href="https://messenger.jhuapl.edu/Explore/Science-Images-Database/gallery-image-238.html">Astrolabe Rupes</a> – a striking feature named after a French Antarctic exploration ship. </p>
<p>Astrolabe Rupes is a 250km long “<a href="http://lroc.sese.asu.edu/posts/374">lobate scarp</a>” – a long, curved structure marking where one part of the planet’s crust has been pushed over nearby terrain, due to the whole planet contracting as it slowly cooled. </p>
<p>There are some much smaller <a href="https://theconversation.com/the-moon-is-still-geologically-active-study-suggests-116768">equivalent features</a> on the Moon, but Mercury is the only nearby celestial body where lobate scarps are known to occur on such a large scale.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A geological feature of Mercury" src="https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424297/original/file-20211002-25-1lyhkp0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Astrolabe Rupes catches the light of the rising sun, captured at a range of 1183km. MPO’s transmitting antenna is brightly lit in the foregound, contributing to a ghosting effect in the middle of the image.</span>
<span class="attribution"><span class="source">ESA/BepiColombo/MTM, CC BY-SA 3.0 IGO</span></span>
</figcaption>
</figure>
<p>Four minutes later, the perspective had changed enough to reveal a wider area: including the lava-flooded, 251km-wide <a href="https://www.esa.int/ESA_Multimedia/Images/2021/10/A_taste_of_Mercury_geology_annotated">Haydn crater</a> and <a href="https://theconversation.com/mysterious-red-spots-on-mercury-get-names-but-what-are-they-95114">Pampu Facula</a>, one of many bright spots likely formed by explosive volcanic eruptions. Both of these features attest to Mercury’s long volcanic history, at its most active more than three billion years ago but probably persisting until around one billion years ago. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A wider-angle view of Mercury's surface" src="https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424298/original/file-20211002-25-1obbu0t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Astrolabe Rupes is still visible in this image taken at 2687km, allowing a wider area of the planet’s surface to be seen.</span>
<span class="attribution"><span class="source">https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/BepiColombo_s_first_views_of_Mercury</span></span>
</figcaption>
</figure>
<p>Meanwhile, camera two focused on Mercury’s northern hemisphere, including the region surrounding <a href="https://www.nasa.gov/mission_pages/messenger/multimedia/messenger_orbit_image20111123_1.html">Calvino crater</a>: an important location for deciphering what lies in the layers of Mercury’s crust. </p>
<p>It also showed Lermontov crater: a region which appears bright because it is host to both <a href="https://news.ncsu.edu/2016/08/byrne-mercury/">volcanic deposits</a> and “hollows”, where a currently unknown <a href="https://www.smithsonianmag.com/smart-news/mercurys-messy-surface-hints-planet-was-once-habitable-180974501/">volatile ingredient</a> of the crust is being lost to space via a mysterious process.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Mercury's North hemisphere" src="https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424299/original/file-20211002-46781-ub8qnv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At 2418km, Mercury’s North hemisphere is towards the lower left, and a brightly sunlit magnetometer boom is in the foreground.</span>
<span class="attribution"><span class="source">ESA/BepiColombo/MTM, CC BY-SA 3.0 IGO</span></span>
</figcaption>
</figure>
<p>Nasa’s <a href="https://solarsystem.nasa.gov/missions/messenger/in-depth/">MESSENGER</a> mission orbited Mercury between 2011 and 2015, revealing a <a href="https://theconversation.com/the-more-we-learn-about-mercury-the-weirder-it-seems-55972">perplexing planet</a>. We are still struggling to understand its composition, origin and history.</p>
<p>Why Mercury has features such as explosive <a href="https://mobile.arc.nasa.gov/public/iexplore/missions/pages/yss/may.html">volcanoes</a> and strange, unique <a href="https://www.planetary.org/articles/02171332-what-are-mercurys-hollows">hollows</a> on its surface is just one of the problems we hope further study will solve. Once in orbit, BepiColombo’s advanced payload of scientific instruments will help us understand more about how Mercury formed and what it’s made of.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-more-we-learn-about-mercury-the-weirder-it-seems-55972">The more we learn about Mercury, the weirder it seems</a>
</strong>
</em>
</p>
<hr>
<p>In the meantime, these extraordinary swing-by pictures at least remind us that we have a healthy spacecraft heading to an exciting destination.</p><img src="https://counter.theconversation.com/content/168159/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Rothery is Professor of Planetary Geosciences at the Open University. He is co-leader of the European Space Agency's Mercury Surface and Composition Working Group, and a Co-Investigator on MIXS (Mercury Imaging X-ray Spectrometer) that is now on its way to Mercury on board the European Space Agency's Mercury orbiter BepiColombo. He has received funding from the UK Space Agency and the Science & Technology Facilities Council for work related to Mercury and BepiColombo, and from the European Commission under its Horizon 2020 programme for work on planetary geological mapping (776276 Planmap). He is author of Planet Mercury - from Pale Pink Dot to Dynamic World (Springer, 2015), Moons: A Very Short Introduction (Oxford University Press, 2015) and Planets: A Very Short Introduction (Oxford University Press, 2010). He is Educator on the Open University's free learning Badged Open Course (BOC) on Moons and its equivalent FutureLearn Moons MOOC, and chair of the Open University's level 2 course on Planetary Science and the Search for Life.</span></em></p>What did Mercury look like as BepiColombo swung by?David Rothery, Professor of Planetary Geosciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1665372021-09-10T12:28:29Z2021-09-10T12:28:29Z9/11 survivors’ exposure to toxic dust and the chronic health conditions that followed offer lessons that are still too often unheeded<figure><img src="https://images.theconversation.com/files/420128/original/file-20210908-22-728gm5.jpg?ixlib=rb-1.1.0&rect=0%2C125%2C2775%2C1859&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Toxic dust hung in the air around ground zero for more than three months following the 9/11 terrorist attacks.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-unidentified-new-york-city-firefighter-walks-away-from-news-photo/1372804?adppopup=true">Anthony Correia/Getty Images</a></span></figcaption></figure><p>The 9/11 terrorist attack on the World Trade Center in New York resulted in the loss of <a href="https://www.cnn.com/2013/07/27/us/september-11-anniversary-fast-facts/index.html">2,753 people in the Twin Towers and surrounding area</a>. After the attack, more than 100,000 responders and recovery workers from every U.S. state – along with <a href="https://www.cdc.gov/wtc/history.html">some 400,000 residents</a> and other workers around ground zero – were exposed to a <a href="https://abcnews.go.com/Health/september-11-toxic-world-trade-center-dust-cloud/story?id=14466933">toxic cloud of dust</a> that fell as a ghostly, thick layer of ash and then hung in the air for more than three months. </p>
<p>The World Trade Center dust plume, or <a href="https://doi.org/10.3109/10408444.2015.1044601">WTC dust</a>, consisted of a dangerous mixture of cement dust and particles, asbestos and a class of chemicals called <a href="https://www.epa.gov/international-cooperation/persistent-organic-pollutants-global-issue-global-response">persistent organic pollutants</a>. These include <a href="https://www.epa.gov/dioxin/learn-about-dioxin">cancer-causing dioxins</a> and <a href="https://www.cdc.gov/biomonitoring/PAHs_FactSheet.html">polyaromatic hydrocarbons, or PAHs</a>, which are byproducts of fuel combustion. </p>
<p>The dust also contained heavy metals that are known <a href="https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health">to be poisonous to the human body and brain</a>, such as lead – used in the manufacturing of flexible electrical cables – and mercury, which is found in float valves, switches and fluorescent lamps. The dust also contained cadmium, a carcinogen <a href="https://doi.org/10.1007/s10534-010-9328-y">toxic to the kidneys</a> that is used in the manufacturing of electric batteries and pigments for paints.</p>
<figure class="align-center ">
<img alt="Smoke pours from the Twin Towers of the World Trade Center in New York City on September 11, 2001." src="https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420341/original/file-20210909-27-p4t2aq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One of the haunting images from 9/11: Smoke pours from the twin towers of the World Trade Center in New York after they were hit by two hijacked airliners.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/smoke-pours-from-the-twin-towers-of-the-world-trade-center-news-photo/1339505?adppopup=true">Robert Giroux via Getty Images</a></span>
</figcaption>
</figure>
<p><a href="http://www.idph.state.il.us/envhealth/factsheets/polychlorinatedbiphenyls.htm#:%7E:text=Polychlorinated%20biphenyls%20(PCBs)%20are%20a,equipment%20like%20capacitors%20and%20transformers.">Polychlorinated biphenyls</a>, human-made chemicals used in electrical transformers, were also part of the toxic stew. PCBs are <a href="https://www.epa.gov/pcbs/learn-about-polychlorinated-biphenyls-pcbs#healtheffects">known to be carcinogenic</a>, toxic to the nervous system and disruptive to the reproductive system. But they became even more harmful when incinerated at high heat from the jets’ fuel combustion and then carried by very fine particles. </p>
<p><a href="https://doi.org/10.3109/10408444.2015.1044601">WTC dust</a> was made up of both “large” particulate matter and very small, fine and ultrafine ones. These particularly small particles are known to be <a href="https://doi.org/10.1038/s41598-018-35398-0">highly toxic</a>, especially to the nervous system since they can travel directly through the <a href="https://doi.org/10.1016/j.neuro.2011.12.001">nasal cavity to the brain</a>. </p>
<p>Many first responders and others who were directly exposed to the dust developed a <a href="https://doi.org/10.3109/10408444.2015.1044601">severe and persistent cough</a> that lasted for a month, on average. They were treated at Mount Sinai Hospital and received care at the Clinic of Occupational Medicine, a well-known center for work-related diseases.</p>
<p>I am a physician specializing in occupational medicine who began working directly with 9/11 survivors in my role as director of the <a href="https://www.cdc.gov/wtc/">WTC Health Program</a> <a href="https://icahn.mssm.edu/about/departments/environmental-public-health/research/wtc-data-center">Data Center</a> at Mount Sinai beginning in 2012. That program collects data, as well as monitors and oversees the public health of WTC rescue and recovery workers. After eight years in that role, I <a href="https://stempel.fiu.edu/faculty/roberto-lucchini/">moved to Florida International University</a> in Miami, where I am planning to continue working with 9/11 responders who are moving to Florida as they reach retirement age.</p>
<figure class="align-center ">
<img alt="In lower Manhattan near Ground Zero, people run away as the North Tower of the World Trade Center collapses." src="https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420343/original/file-20210909-23-1bc9fnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Remembering 9/11: As the north tower of the World Trade Center collapses, a cloud of toxic gas chases terrified residents and tourists.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-run-away-as-the-north-tower-of-world-trade-center-news-photo/1339533?adppopup=true">Jose Jimenez/Primera Hora via Getty Images</a></span>
</figcaption>
</figure>
<h2>From acute to chronic conditions</h2>
<p>After the initial “acute” health problems that 9/11 responders faced, they soon began experiencing a wave of chronic diseases that <a href="https://doi.org/10.3390/ijerph18126383">continue to affect them</a> 20 years later. The persistent cough gave way to <a href="https://doi.org/10.1001/dmp.2011.58">respiratory diseases</a> such as asthma, chronic obstructive pulmonary disease (COPD) and upper airway diseases such as <a href="https://doi.org/10.1136/oemed-2015-103094">chronic rhinosinusitis</a>, laryngitis and nasopharyngitis. </p>
<p>The litany of respiratory diseases also put many of them at risk for <a href="https://doi.org/10.1038/ajg.2011.357">gastroesophageal reflux disease</a> (GERD), which occurs at a <a href="https://doi.org/10.1097/JOM.0b013e3181845f9b">higher rate in WTC survivors</a> than in the general population. This condition occurs when stomach acids reenter the esophagus, or food pipe, that connects the stomach to the throat. As a consequence of either the airway or the digestive disorders, many of these survivors also <a href="https://doi.org/10.1097/JOM.0b013e3182305282">struggle with sleep apnea</a>, which requires additional treatments.</p>
<p>Further compounding the tragedy, about eight years after the attacks, <a href="https://doi.org/10.1093/jncics/pkz090">cancers began to turn up</a> in 9/11 survivors. These include tumors of the blood and lymphoid tissues such as lymphoma, myeloma and leukemia, which are well known to <a href="https://doi.org/10.1186/1745-6673-8-14">affect workers exposed to carcinogens</a> in the workplace. But survivors also suffer from other cancers, including breast, head and neck, prostate, lung and thyroid cancers. </p>
<p>Some have also developed mesothelioma, an aggressive form of cancer related to <a href="http://dx.doi.org/10.1136/thoraxjnl-2013-204161">exposure to asbestos</a>. <a href="https://www.9news.com.au/9stories/september-11-death-toll-from-terror-attack-could-rise-by-millions-due-to-toxic-asbestos-dust/8bc90677-0032-42a2-82f9-4b9baad753d9">Asbestos</a> was used in the early construction of the north tower until public advocacy and broader awareness of its health dangers <a href="https://www.mesothelioma.com/states/new-york/world-trade-center/">brought its use to a halt</a>.</p>
<p>And the psychological trauma that 9/11 survivors experienced has left many suffering from persistent mental health challenges. One <a href="https://doi.org/10.1007/s10488-019-00998-z">study</a> published in 2020 found that of more than 16,000 WTC responders for whom data was collected, nearly half reported a need for mental health care, and 20% of those who were directly affected developed <a href="https://doi.org/10.1016/j.dadm.2016.08.001">post-traumatic stress disorder</a>. </p>
<p>Many have told me that the contact they had with parts of human bodies or with the deadly scene and the tragic days afterward left a permanent mark on their lives. They are unable to forget the images, and many of them suffer from mood disorders as well as <a href="https://doi.org/10.1186/s12940-019-0449-7">cognitive impairments and other behavioral issues</a>, including substance use disorder. </p>
<figure class="align-center ">
<img alt="On 9/11, shortly after the terrorist attack in New York City, a distraught survivor sits outside the World Trade Center." src="https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420347/original/file-20210909-23-do7s5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Remembering 9/11: A distraught survivor sits outside the World Trade Center after the terrorist attack.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/survivor-sits-outside-the-world-trade-center-after-two-news-photo/50833029?adppopup=true">Jose Jimenez/Primera Hora via Getty Images</a></span>
</figcaption>
</figure>
<h2>An aging generation of survivors</h2>
<p>Now, 20 years on, these survivors face a new challenge as they age and move toward retirement – a <a href="https://doi.org/10.3386/w12123">difficult life transition</a> that can sometimes lead to mental health decline. Prior to retirement, the daily drumbeat of work activity and a steady schedule often helps keep the mind busy. But retirement can sometimes leave a void – one that for 9/11 survivors is too often filled with unwanted memories of the noises, smells, fear and despair of that terrible day and the days that followed. Many survivors have told me they do not want to return to Manhattan and certainly not to the WTC. </p>
<p>Aging can also bring with it forgetfulness and other cognitive challenges. But studies show that these natural processes are <a href="https://doi.org/10.1186/s12940-019-0449-7">accelerated and more severe</a> in 9/11 survivors, similar to the experience of veterans from war zones. This is a concerning trend, but all the more so because a growing body of research, including <a href="https://doi.org/10.21203/rs.3.rs-846359/v1">our own preliminary study</a>, is finding links between <a href="https://doi.org/10.1192/bjp.bp.105.014779">cognitive impairment in 9/11 responders and dementia</a>. A recent <a href="https://www.washingtonpost.com/magazine/2021/08/30/911-first-responders-dementia/">Washington Post piece detailed</a> how 9/11 survivors are experiencing these dementia-like conditions in their 50s – far earlier than is typical. </p>
<p>The COVID-19 pandemic, too, has taken a toll on those who have already suffered from 9/11. People with <a href="https://doi.org/10.1016/j.eclinm.2020.100515">preexisting conditions</a> have been at far higher risk during the pandemic. Not surprisingly, a recent study found a <a href="https://doi.org/10.1371/journal.pone.0254713">higher incidence of COVID-19</a> in WTC responders from January through August 2020.</p>
<h2>Honoring the 9/11 survivors</h2>
<p>The health risks posed by direct exposure to the acrid dust was underestimated at the time, and poorly understood. Appropriate personal protective equipment, such as P100 half-face respirators, was not available at that time. </p>
<p>But now, over 20 years on, we know much more about the risks – and we have much greater access to protective equipment that can keep responders and recovery workers safe following disasters. Yet, too often, I see that we have not learned and applied these lessons. </p>
<p>For instance, in the immediate aftermath of the <a href="https://www.nytimes.com/live/2021/07/06/us/miami-building-collapse-updates">condominium collapse</a> near Miami Beach last June, it took days before P100 half-face respirators were fully available and made mandatory for the responders. Other examples around the world are even worse: One year after the <a href="https://www.npr.org/2021/08/04/1024275186/a-year-after-the-beirut-explosion-victims-families-continue-to-push-for-justice">Beirut explosion</a> in August 2020, very little action had been taken to investigate and manage the physical and <a href="https://timep.org/commentary/analysis/the-beirut-explosions-impact-on-mental-health/">mental health consequences </a> among responders and the impacted community.</p>
<p>Applying the lessons learned from 9/11 is a critically important way to honor the victims and the brave men and women who took part in the desperate rescue and recovery efforts back on those terrible days.</p><img src="https://counter.theconversation.com/content/166537/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roberto Lucchini receives funding from CDC/NIOSH to study the cognitive impacts associated to the WTC exposure to neurotoxins and to intense psychological trauma. </span></em></p>Those directly exposed to toxic dust and trauma on and after 9/11 carry with them a generation of chronic health conditions, which are placing them at higher risk during the pandemic and as they age.Roberto Lucchini, Professor of Occupational and Environmental Health Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1660462021-08-23T10:48:52Z2021-08-23T10:48:52ZThe five most impressive geological structures in the solar system<figure><img src="https://images.theconversation.com/files/417379/original/file-20210823-13-aqa2uc.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C1581%2C1505&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ligeia Mare on Titan.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Ligeia_Mare#/media/File:Ligeia_Mare_in_false_color_(PIA17031).jpg">NASA/JPL-Caltech/ASI/Cornell -</a></span></figcaption></figure><p>When we talk about amazing geological features, we often limit ourselves to those on Earth. But as a geologist, I think that’s crazy – there are so many structures on other worlds that can excite and inspire, and that can put processes on our own planet into perspective.</p>
<p>Here, in no particular order, are the five geological structures in the solar system (excluding Earth) that most impress me.</p>
<h2>The grandest canyon</h2>
<p>I left out the solar system’s biggest volcano, <a href="https://theconversation.com/monster-volcanoes-on-mars-how-space-rocks-are-helping-us-solve-their-mysteries-85045">Olympus Mons</a> on Mars, so I could include that planet’s most spectacular canyon, <a href="https://www.space.com/20446-valles-marineris.html">Valles Marineris</a>. Being 3,000km long, hundreds of kilometres wide and up to eight kilometres deep, this is best seem from space. If you were lucky enough to stand on one rim, the opposite rim would be way beyond the horizon. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Image of Marineris seen in a colour-coded topographic view." src="https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=191&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=191&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=191&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=240&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=240&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416017/original/file-20210813-17-1pochz0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=240&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Valles Marineris seen in a colour-coded topographic view as if from 5,000 km above the surface (left), and imaged by the High Resolution Stereo Camera on Esa’s Mars Express (right).</span>
<span class="attribution"><span class="source">Google Earth and NASA/USGS/ESA/DLR/FU Berlin (G. Neukum)</span></span>
</figcaption>
</figure>
<p>It was probably initiated by fracturing when an adjacent volcanic region (called <a href="https://astronomynow.com/tag/tharsis-volcanic-dome/">Tharsis</a>) began to bulge upwards, but was widened and deepened by a series of catastrophic floods that climaxed more than 3 billion years ago.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/plate-tectonics-new-findings-fill-out-the-50-year-old-theory-that-explains-earths-landmasses-55424">Plate tectonics: new findings fill out the 50-year-old theory that explains Earth's landmasses</a>
</strong>
</em>
</p>
<hr>
<h2>Venus’ fold mountains</h2>
<p>We are going to learn a lot more about Venus in the 2030s when <a href="https://theconversation.com/nasa-has-announced-two-missions-to-venus-by-2030-heres-why-thats-exciting-162133">two Nasa missions</a> and <a href="https://www.esa.int/Science_Exploration/Space_Science/ESA_selects_revolutionary_Venus_mission_EnVision">one from Esa (European Space Agency)</a> arrive. Venus is nearly the same size, mass and density as the Earth, causing <a href="https://theconversation.com/venus-has-very-few-volcanoes-weirdly-this-might-be-why-its-as-hot-as-hell-78363">geologists to puzzle</a> over why it lacks Earth-style plate tectonics and why (or indeed whether) it has comparatively little active volcanism. How does the planet get its heat out?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Image of the fold mountains on Venus." src="https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=551&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=551&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416030/original/file-20210813-25-ofb1wa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=551&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fold mountains in Ovda Regio, Venus. The insert is a similar view of part of the Applachians in central Pennsylvania.</span>
<span class="attribution"><span class="source">NASA/JPL</span></span>
</figcaption>
</figure>
<p>I find it reassuring that at least some aspects of Venus’ geology look familiar. For example, the northern margin of the highlands named <a href="https://www.jpl.nasa.gov/images/venus-ovda-regio">Ovda Regio</a> looks strikingly similar, apart from the lack of rivers cutting through the eroded, fold-like pattern, to “fold mountains” on Earth such as the <a href="https://www.nationalgeographic.org/encyclopedia/fold-mountain/">Appalachians</a>, which are the result of a <a href="https://www.nationalgeographic.org/encyclopedia/fold-mountain/">collision between continents</a>.</p>
<h2>Blasted Mercury</h2>
<p>I’m cheating a little with my next example, because it is both one of the solar system’s largest impact basins and an explosive volcano within it. Mercury’s 1,550km diameter <a href="https://solarsystem.nasa.gov/resources/2266/mercurys-caloris-basin/">Caloris basin</a> was formed by a major asteroid impact about 3.5 billion years ago, and soon after that its floor was flooded by lavas. </p>
<p>Some time later, a series of explosive eruptions blasted kilometres-deep holes through the solidified lavas near the edge of the basin where the lava cap was thinnest. These sprayed volcanic ash particles out over a range of tens of kilometres. One such deposit, named Agwo Facula, surrounds the explosive vent that I have chosen as my example. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Images of Mercury's Caloris basin." src="https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416045/original/file-20210813-13-osbbma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Right: most of Mercury’s Caloris basin, its floor covered by dull, orange lava. Brighter orange patches are remnants of explosive eruptions. Lower left: close-up inside the red box of an explosive volcanic deposit. Upper left: details of the vent interior.</span>
<span class="attribution"><span class="source">NASA/JHUAPL/CIW</span></span>
</figcaption>
</figure>
<p>Explosive eruptions are driven by the force of expanding gas, and are a <a href="https://theconversation.com/mysterious-red-spots-on-mercury-get-names-but-what-are-they-95114">surprising find on Mercury</a>, whose proximity to the Sun was previously expected to have starved it of such volatile substances – the heat would have made them boil off. Scientists suspect that there were in fact several explosive eruptions, possibly spaced over a prolonged timescale. This means that gas-forming volatile materials (whose composition will remain uncertain until <a href="https://theconversation.com/europe-blasts-off-to-mercury-heres-the-rocket-science-104641">Esa’s BepiColombo</a> mission starts work in 2026) were repeatedly available in Mercury’s magmas.</p>
<h2>The tallest cliff?</h2>
<p>In soil or vegetation-rich regions on Earth, cliffs offer the largest exposures of clean rock. Although <a href="https://www.bbc.co.uk/news/uk-england-dorset-56773648">dangerous to approach</a>, they reveal an uninterrupted cross-section of rock and can be great for fossil hunting. Because geologists love them so much, I give you the seven kilometres-high <a href="https://spaceplace.nasa.gov/cliff-jumping/en/">Verona Rupes</a>. This is a feature on Uranus’s small moon <a href="https://solarsystem.nasa.gov/moons/uranus-moons/miranda/in-depth/">Miranda</a> that is often described as “the tallest cliff in the solar system”, including on a <a href="https://science.nasa.gov/verona-rupes-tallest-known-cliff-solar-system">recent Nasa website</a>. This even goes so far as to remark that if you were careless enough to take a tumble off the top, it would take you 12 minutes to fall to the bottom. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Images of Verona Rupes." src="https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=592&fit=crop&dpr=1 600w, https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=592&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=592&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=744&fit=crop&dpr=1 754w, https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=744&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/415845/original/file-20210812-15866-1l1jbhp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=744&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Verona Rupes, about 50km long and several km high, but not actually so cliff-like as it appears as seen by Voyager 2 during its 1986 flyby.</span>
<span class="attribution"><span class="source">NASA/JPL</span></span>
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Read more:
<a href="https://theconversation.com/mysterious-red-spots-on-mercury-get-names-but-what-are-they-95114">Mysterious red spots on Mercury get names – but what are they?</a>
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<p>This is nonsense, because Verona Rupes is nowhere near vertical. The only images we have of it are from <a href="https://solarsystem.nasa.gov/missions/voyager-2/in-depth/">Voyager 2</a>, captured during its 1986 fly by of Uranus. It is undeniably impressive, being almost certainly a geological fault where one block of Miranda’s icy crust (the outermost “shell” of the planet) has moved downwards against the adjacent block. </p>
<p>However, the obliqueness of the view is deceptive, making it impossible to be sure of the face’s steepness – it probably slopes at less than 45 degrees. If you stumbled at the top, I doubt you’d even slide to the bottom. The face appears to be very smooth in the best, but rather low resolution image that we have, but at Miranda’s -170°C daytime temperature, water-ice has a <a href="https://www.zmescience.com/science/ice-slippery-h-bonds-8731058/">high friction</a> and is not slippery at all.</p>
<h2>Titan’s drowned coastline</h2>
<p>For my final example I could happily have chosen virtually anywhere on Pluto, but instead I have opted for a hauntingly Earth-like coastline on Saturn’s largest moon, <a href="https://theconversation.com/flying-on-saturns-moon-titan-what-we-could-discover-with-nasas-new-dragonfly-mission-119823">Titan</a>. Here, a large depression in Titan’s water-ice “bedrock” hosts a sea of liquid methane named <a href="https://www.esa.int/ESA_Multimedia/Images/2013/06/Ligeia_Mare">Ligeia Mare</a>.</p>
<p>Valleys carved by methane rivers draining into the sea have evidently become flooded as the sea level rose. This complexly indented coastline reminds me strongly of Oman’s <a href="https://www.bbc.com/travel/article/20120323-omans-sleepy-peninsula">Musandam peninsula</a>, on the south side of the Straits of Hormuz. There, the local crust has been warped downwards because of the ongoing collision between Arabian and the Asian mainlands. Has something similar happened on Titan? We don’t know yet, but the way that the coastal geomorphology changes around Ligeia Mare suggests to me that its drowned valleys are more than a straightforward result of rising liquid levels.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Images of Ligeia Mare and The Musandam peninsula side by side." src="https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=319&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=319&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=319&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=401&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=401&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416316/original/file-20210816-28-tx30nn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=401&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left: Part of Titan’s Ligeia Mare, showing a coastline with valleys drowned by a sea of liquid methane. Right: The Musandam peninsula, Arabia, where coastal valleys are similarly drowned, but by a saltwater sea.</span>
<span class="attribution"><span class="source">NASA/JPL-Caltech/ASI/Cornell and Expedition 63, International Space Station (ISS)</span></span>
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Read more:
<a href="https://theconversation.com/titan-first-global-map-uncovers-secrets-of-a-potentially-habitable-moon-of-saturn-126985">Titan: first global map uncovers secrets of a potentially habitable moon of Saturn</a>
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<p>Rock and liquid water on Earth, frigid water-ice and liquid methane on Titan - it makes little difference. Their mutual interactions are the same, and so we see geology repeating itself on different worlds.</p><img src="https://counter.theconversation.com/content/166046/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Rothery is Professor of Planetary Geosciences at the Open University. He is co-leader of the European Space Agency's Mercury Surface and Composition Working Group, and a Co-Investigator on MIXS (Mercury Imaging X-ray Spectrometer) that is now on its way to Mercury on board the European Space Agency's Mercury orbiter BepiColombo. He has received funding from the UK Space Agency and the Science & Technology Facilities Council for work related to Mercury and BepiColombo, and from the European Commission under its Horizon 2020 programme for work on planetary geological mapping (776276 Planmap). He is author of Planet Mercury - from Pale Pink Dot to Dynamic World (Springer, 2015), Moons: A Very Short Introduction (Oxford University Press, 2015) and Planets: A Very Short Introduction (Oxford University Press, 2010). He is Educator on the Open University's free learning Badged Open Course (BOC) on Moons and its equivalent FutureLearn Moons MOOC, and chair of the Open University's level 2 course on Planetary Science and the Search for Life.</span></em></p>From the tallest cliff in the solar system to its largest impact basin, geological processes on other worlds are very similar to those on our own planet.David Rothery, Professor of Planetary Geosciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1631802021-07-05T20:09:33Z2021-07-05T20:09:33ZA tale of two valleys: Latrobe and Hunter regions both have coal stations, but one has far worse mercury pollution<figure><img src="https://images.theconversation.com/files/409603/original/file-20210705-24485-171gkid.jpg?ixlib=rb-1.1.0&rect=0%2C48%2C5404%2C3527&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We know coal-fired power stations can generate high levels of carbon dioxide, but did you know they can be a major <a href="https://www.epa.gov/mats/cleaner-power-plants">source of mercury</a> emissions as well?</p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0269749121011787">new research</a> compared the level of mercury pollution in the Hunter Valley in New South Wales and the Latrobe Valley in Victoria. </p>
<p>And we found power stations in the Latrobe Valley emit around 10 times more mercury than power stations in the Hunter Valley. Indeed, the mercury level in the Latrobe Valley environment is 14 times higher than what’s typically natural for the region. </p>
<p>So why is there such a stark difference between states? Well, it has a lot to do with regulations. </p>
<p>Following <a href="https://www.epa.nsw.gov.au/-/media/epa/corporate-site/resources/air/18p0700-review-of-coal-fired-power-stations.pdf">a NSW requirement</a> for power stations to install pollution control technology, mercury levels in the environment dropped. In Victoria, on the other hand, coal-fired power stations continue to operate without some of the air pollution controls NSW and other developed countries have mandated. </p>
<p>To minimise the safety risks that come with excessive mercury pollution, coal-fired power stations in all Australian jurisdictions should adopt the best available technologies to reduce mercury emissions.</p>
<h2>A dangerous neurotoxin</h2>
<p><a href="https://www.epa.gov/mercury/health-effects-exposures-mercury">Mercury is a neurotoxin</a>, which means it can damage the nervous system, brain and other organs when a person or animal is exposed to unsafe levels. </p>
<p>Coal naturally contains mercury. So when power stations burn coal, mercury is released to the atmosphere and is then deposited back onto the Earth’s surface. When a high level of mercury ends up in bodies of water, such as lakes and rivers, it can be transferred to fish and other aquatic organisms, exposing people and larger animals to mercury that feed on these fish. </p>
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Read more:
<a href="https://theconversation.com/the-death-of-coal-fired-power-is-inevitable-yet-the-government-still-has-no-plan-to-help-its-workforce-156863">The death of coal-fired power is inevitable — yet the government still has no plan to help its workforce</a>
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<p>Mercury does not readily degrade or leave aquatic environments such as lakes and rivers. It’s a persistent toxic element — once present in water, it’s there to stay.</p>
<p>The amount of mercury emitted depends on the type of coal burnt (black or brown) and the type of pollution control devices the power stations use. </p>
<p>The Latrobe Valley stations in Victoria burn brown coal, which has more mercury than the black coal typically found in NSW. Despite this, Victorian regulations have historically not placed specific limits on mercury emissions.</p>
<p>In contrast, <a href="https://www.epa.nsw.gov.au/-/media/epa/corporate-site/resources/air/18p0700-review-of-coal-fired-power-stations.pdf">NSW power plants are required to use “bag filters”</a>, a technology that’s used to trap mercury (and other) particles before they enter the atmosphere. </p>
<p>While bag filters alone fall short of the world’s best practices, they can still be effective. In fact, <a href="https://www.sciencedirect.com/science/article/pii/S0269749121011787">after bag filters were retrofitted</a> to Hunter Valley’s Liddell power station in the early 1990s, mercury deposition in the surrounding environment halved. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=559&fit=crop&dpr=1 600w, https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=559&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=559&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=702&fit=crop&dpr=1 754w, https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=702&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/409632/original/file-20210705-17-1ufcbsh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=702&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Mercury deposited in sediments of Lake Glenbawn (left) in the Hunter Valley and Traralgon Railway Reservoir (right) in the Latrobe Valley.</span>
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<p>The <a href="http://www.mercuryconvention.org/Portals/11/documents/forms-guidance/English/BATBEP_coal.pdf">best available technology to control mercury emissions</a> from coal-fired power plants is a combination of “wet flue-gas desulfurization” (which removes mercury in its gaseous form) and bag filters (which removes mercury bound to particles). </p>
<p>This is what’s been adopted across North America and parts of Europe. It not only filters out mercury, but also removes sulphur dioxide, nitrogen oxides and other toxic air compounds.</p>
<h2>Using lake sediments to see into the past</h2>
<p>Lake sediments can capture mercury deposited from the atmosphere and from surrounding areas. Sediments that contain this mercury accumulate at the bottom of lakes over time — the deeper the sediment, the further back in time we can analyse.</p>
<p>We took sediment samples from lakes in the Latrobe and Hunter valleys, and dated them back to 1940 to get a historical record of mercury deposition. </p>
<p>This information can help us understand how much naturally occurring mercury there was before coal-fired power stations were built, and therefore show us the impact of burning coal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A power station by a lake" src="https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/409605/original/file-20210705-25185-1o8rrf5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lake Narracan: one of the lakes we sampled sediments from, near a coal-fired power station in Latrobe Valley.</span>
<span class="attribution"><span class="source">Larissa Schneider</span>, <span class="license">Author provided</span></span>
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<p>From these records, we found the adoption of bag filters in the Hunter Valley corresponded with mercury depositions declining in NSW from the 1990s. </p>
<p>In contrast, in Victoria, where there’s been no such requirement, mercury emissions and depositions have continued to increase since Hazelwood power station was <a href="https://theconversation.com/hazelwood-power-station-from-modernist-icon-to-greenhouse-pariah-75217">completed in 1971</a>. </p>
<h2>What do we do about it?</h2>
<p>In March, the Victorian government <a href="https://www.epa.vic.gov.au/about-epa/what-we-do/works-approvals-and-licences/improving-licensing/brown-coal-fired-power-stations-licence-review">announced changes</a> to the regulatory licence conditions for brown coal-fired power stations. Although mercury emissions allowances have been included for the first time, they’re arguably still too high, and there’s no requirement to install specific pollution control technologies. </p>
<p>There’s a risk this approach won’t reduce mercury emissions from existing levels. Victoria should instead consider more ambitious regulations that encourage the adoption of best practice technology to help protect local communities and the environment. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C4188%2C2758&q=45&auto=format&w=1000&fit=clip"><img alt="Coal-fired power station at the end of a road, at night" src="https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C4188%2C2758&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/409602/original/file-20210705-13832-2d8wa6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Loy Yang power station, Victoria’s largest, burns brown coal which contains more mercury.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>Another vital step toward protecting human health and the environment from mercury is for the federal government to ratify the <a href="https://www.mercuryconvention.org/">Minamata Convention on Mercury</a>, an international treaty to protect human health and the environment from mercury.</p>
<p>Despite <a href="https://www.environment.gov.au/protection/chemicals-management/mercury">signing the convention in 2013</a>, the Australian government is yet to ratify it, which is required to make it legally binding in Australia. </p>
<p>Ratifying the convention will oblige state and federal governments to develop and implement a strategy to reduce mercury emissions, including from coal-fired power stations across Australia. And this strategy should include rolling out effective technologies — our research shows it can make a big difference.</p>
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<p><em>The authors acknowledge Lauri Myllyvirta from the Centre for Research on Energy and Clean Air for her contributions to this article.</em></p>
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Read more:
<a href="https://theconversation.com/hazelwood-power-station-from-modernist-icon-to-greenhouse-pariah-75217">Hazelwood power station: from modernist icon to greenhouse pariah</a>
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<img src="https://counter.theconversation.com/content/163180/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Larissa Schneider receives funding from the Australian Research Council on the long-term history of mercury in Australasia (DE180100573) and from the Asia Pacific Innovation Program (APIP) 2017 and 2018.</span></em></p><p class="fine-print"><em><span>Nothing to disclose.</span></em></p><p class="fine-print"><em><span>Cameron Holley receives funding from the Australian Research Council on Non-urban water governance (DP190101584) and Integrated governance of water and coal seam gas (DP170100281).</span></em></p><p class="fine-print"><em><span>Darren Sinclair receives funding from the Australian Research Council on Non-urban water governance (DP190101584).</span></em></p><p class="fine-print"><em><span>Simon Haberle receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Neil Rose and Ruoyu Sun do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research found power stations in the Latrobe Valley emit around 10 times more mercury than power stations in the Hunter Valley. The stark difference has a lot to do with regulations.Larissa Schneider, DECRA fellow, Australian National UniversityAnna Lintern, Lecturer, Monash UniversityCameron Holley, Professor, UNSW SydneyDarren Sinclair, Professor, University of CanberraNeil Rose, Professor of Environmental Pollution and Palaeolimnology, UCLRuoyu Sun, Associate ProfessorSimon Haberle, Professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1594162021-05-06T20:33:44Z2021-05-06T20:33:44ZPictures from outer space reveal the extent of illegal gold mining in Peru<figure><img src="https://images.theconversation.com/files/398733/original/file-20210504-13-fc6ckt.jpeg?ixlib=rb-1.1.0&rect=27%2C0%2C3012%2C2006&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An astronaut aboard the International Space Station (ISS) took this photograph of numerous gold prospecting pits in eastern Peru.</span> <span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/147891/gold-rush-in-the-peruvian-amazon">(NASA/SS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center)</a></span></figcaption></figure><p>In the Madre de Dios region of Peru, a human-made wasteland brushes up against the border of the Amazonian rainforest. Over the past decade, small-scale illegal gold miners have transformed the landscape from tree-covered marshlands to a desert pockmarked with polluted ponds, leaking mercury into the local food web. </p>
<p>Multiple government crackdowns have tried to stamp out these artisanal gold mining activities to protect the national forests, but illegal operations are often able to shift location without attracting attention, creating a moving — and hard to find — target. However, artificial intelligence offers new hope.</p>
<p>NASA is backing the use of machine learning-enhanced satellite technology to capture the subtle movements of illegal gold mining in climate-sensitive areas of the world. While still in early stages, this novel innovation aims to help preserve the Amazon and the health of local communities in Peru, Latin America’s largest gold producer.</p>
<h2>Environmental destruction</h2>
<p>Miners in the Madre de Dios region use the same basic tools as miners did in the 1850s gold rushes in North America: a high pressure hose to blast off layers of rock and a handmade sluice lined with towels to collect the runoff. Heavy metals get caught in the towel fibres, and mercury is used to collect the gold.</p>
<p>“You can basically learn how to be a miner in a half an hour,” says Luis Fernandez, executive director of <a href="https://cees.wfu.edu/cincia/">Wake Forest University’s Center for Amazonian Scientific Innovation</a> who has studied gold mining in the Madre de Dios region for decades. A novice miner could <a href="https://doi.org/10.1038/d41586-020-00119-z">uncover 10-15 grams of gold a day</a>, worth a few hundred dollars on the global market.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="broken camp materials on the shores of a polluted river" src="https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398736/original/file-20210504-21-kz66td.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A destroyed illegal mining camp in Peru’s Tambopata province.</span>
<span class="attribution"><span class="source">(AP Photo/Rodrigo Abd)</span></span>
</figcaption>
</figure>
<p>But this type of gold mining is environmentally disastrous, choking rivers and deforesting the land. The mercury used in gold mining can also poison local water systems, <a href="https://doi.org/10.1039/C4EM00567H">contaminating the wildlife and people downstream</a>. Mercury is a neurotoxin that poisons the nervous system. Gold miners have some of the <a href="https://doi.org/10.1007/s00420-011-0615-x">highest documented mercury exposures ever recorded</a>.</p>
<p>Much of the mercury used in gold mining also ends up in the atmosphere and eventually contaminates global seafood stocks. Tuna in oceans around the world accumulate <a href="https://doi.org/10.3390/ijerph14010105">mercury that came from gold mining operations</a>, such as those in Madre de Dios.</p>
<h2>Government attempts</h2>
<p>The Peruvian government has tried to prevent illegal gold mining in Madre de Dios for over a decade through military interventions. The most recent and largest effort in 2019, called Operation Mercurio, aimed to remove La Pampas, the largest illegal mining town in the region. The Peruvian military bombed illegal mining equipment, patrolled protected zones and arrested illegal gold miners. </p>
<p>But many of these efforts have proved ineffective in the face of rising gold prices. “They call it the balloon effect,” says Fernandez. “You squeeze a balloon in one part, and it pops out the other.” </p>
<p>Illegal miners simply migrate to other sites to avoid the government’s presence. With no way to track them, the government has had little hope of addressing the problem — until now.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/yEecStCFfo8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In 2019, Peru established Operation Mercurio to address illegal mining.</span></figcaption>
</figure>
<h2>Surveillance from space</h2>
<p>While past satellite images couldn’t capture subtle signs of mining, environmental scientist David Lutz, from Dartmouth University, is integrating NASA’s database with commercial images from the past five years to improve their resolution. Then his team uses new computer vision algorithms to identify mining activity.</p>
<p>“This methodology allows us to add human-use objects into the equation, offering a level of detail that was previously invisible to us,” says Lutz. Researchers can now pick up small shifts in the colour and reflectance of mining ponds, location of mining equipment and size of rock piles to reveal illegal mining activity.</p>
<p>Under pandemic conditions, Fernandez expects illegal gold mining is on the rise. “The combination of really high [gold] prices, increasing poverty and reduced governance to me equals more illegal gold mining.” This resurgence demonstrates the major critique of the government crackdowns: they don’t last.</p>
<p>Madre de Dios is one of the poorest regions in Peru. Illegal gold mining provides a temporary income for day labourers, but ultimately, “it’s a poverty trap for people at the low end of the enterprise,” says Fernandez. As a career, there is no skill development, no long-term benefits and horrible health consequences. Military interventions do nothing to change these dynamics unless they are paired with alternative livelihood options.</p>
<p>While the analysis is still in progress, Lutz hopes these machine learning-enhanced images will help clarify whether past interventions were useful and help direct future policy that will truly protect both the Amazon and local communities.</p><img src="https://counter.theconversation.com/content/159416/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>NASA satellite images reveal the extent of gold-mining in Peru. This information can be used to shut down illegal mining and prevent environmental destruction and contamination.Robin Blades, Global Journalism Fellow, Dalla Lana School of Public Health, University of TorontoPaleah Moher, Dalla Lana School Fellowship in Global Journalism, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1531782021-02-19T13:19:19Z2021-02-19T13:19:19ZWomen of color spend more than $8 billion on bleaching creams worldwide every year<figure><img src="https://images.theconversation.com/files/382789/original/file-20210205-13-1d5k6lc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Skin-lightening creams for sale in a shop in New Delhi, India, in 2020. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/this-photo-taken-on-july-8-2020-shows-packages-of-unilever-news-photo/1226007169?adppopup=true">Sajjad Hussain / Getty Images</a></span></figcaption></figure><figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384056/original/file-20210212-17-19nbl8g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>The idealization of light skin as the pinnacle of beauty <a href="https://www.nytimes.com/2016/11/26/fashion/skin-bleaching-south-africa-women.html">affects self-esteem</a> for women of color around the world. In many cultures, skin color is a <a href="https://doi.org/10.3389/fpsyg.2019.01516">social benchmark</a> that is often used by people of color and whites alike in lieu of race. Attractiveness, marriageability, career opportunities and socioeconomic status are directly <a href="https://www.nytimes.com/2010/01/16/health/16skin.html">correlated</a> with skin color. </p>
<p>As a result, many women of color seek chemical remedies to lighten their complexion. They have created a booming global business in bleach creams and <a href="https://www.un.org/africarenewal/magazine/april-2019-july-2019/paying-high-price-skin-bleaching">injectables</a> valued at <a href="https://www.strategyr.com/market-report-skin-lighteners-forecasts-global-industry-analysts-inc.asp">US$8.6 billion</a> in 2020; $2.3 billion was spent in the U.S. alone. The market is projected to reach $12.3 billion by 2027. </p>
<p>In my <a href="https://scholar.google.com/citations?user=lfBeq78AAAAJ&hl=en">work</a> in behavioral science and colorism, I studied the phenomenon of skin bleaching during a decade of travel around the world during which I visited every major racial group – and tracked the <a href="https://theconversation.com/bleached-girls-india-and-its-love-for-light-skin-80655">growth of this industry</a>. The practice has both significant racial implications and health concerns. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IqsSG4qvWdo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A new Netflix documentary called ‘Skin’ explores the practice of skin bleaching in African culture.</span></figcaption>
</figure>
<h2>A common practice</h2>
<p>As I stated during my interview on Oprah’s 2015 “Light Girls” documentary, while bleaching the skin is common, it’s both <a href="https://tubitv.com/movies/514763/light-girls">dangerous and potentially life-threatening</a> because products contain steroids, hydroquinone bleach and mercury. The World Health Organization <a href="https://www.washingtonpost.com/politics/2019/06/15/dangerous-skin-bleaching-has-become-public-health-crisis-corporate-marketing-lies-behind-it/">warns</a> that skin bleaching can cause liver and kidney damage, neurological problems, cancer and, for pregnant women, stillbirth.</p>
<p>The practice is not new. It became <a href="https://www.un.org/africarenewal/magazine/april-2019-july-2019/paying-high-price-skin-bleaching">popular in many African countries</a> in the 1950s; today, about 77% of Nigerians, 27% of Senegalese and 35% of South African women bleach their skin. Indian caste-based discrimination was outlawed in 1950, but dark-skinned women (and men) are still <a href="https://www.pri.org/stories/2019-03-05/even-harvard-pedigree-caste-follows-shadow">persecuted</a> – and fair skin remains a distinguishing social factor, associated with purity and elite status. </p>
<p>In the Middle East, the practice of bleaching is most common in <a href="https://doi.org/10.1111/j.1365-4632.2010.04463.x">Jordan</a>, with 60.7% of women bleaching. The Brazilian government seems to sanction white skin over dark by encouraging <a href="https://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=1551&context=law_globalstudies">immigration from Europe and discouraging persons of African descent</a>. </p>
<p>Light skin is idealized in North America, but the phenomenon is contentious because bleaching is perceived as a desire to be white. So bleaching creams are <a href="https://www.latimes.com/archives/la-xpm-2006-aug-30-na-skincream30-story.html">marketed in the U.S.</a> not to lighten skin, but to “erase blemishes” and “age spots.”</p>
<p>Their <a href="https://theconversation.com/black-americas-bleaching-syndrome-82200">use in the U.S. spiked</a> after the 1967 U.S. Supreme Court <a href="https://scholar.google.com/scholar_case?case=5103666188878568597&q=Loving+v.+Virginia&hl=en&as_sdt=6,33&as_vis=1">ruling</a> that legalized interracial marriage. </p>
<p>In the aftermath of the civil rights movement, dark-complected immigrants from developing countries flocked to the U.S., carrying with them an ideal of light-skinned beauty – and they <a href="https://www.law.uci.edu/lawreview/vol3/no4/Jones.pdf">bleached their skin to attain it</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Kl2lpnoGyyw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Ideals of light-skinned beauty stemming from European colonization contributed to a lucrative bleach cream industry.</span></figcaption>
</figure>
<h2>Perpetuating ‘colorism’</h2>
<p>Bleach cream manufacturers now face growing pressure to address racism, with activists arguing that their products perpetuate a preference for lighter skin. In 2020, Johnson & Johnson announced that it will <a href="https://www.nytimes.com/2020/06/19/business/johnson-and-johnson-skin-whitening-cream.html">no longer sell</a> two products marketed to reduce dark spots that were widely used as skin lighteners. </p>
<p>L’Oreal, the world’s largest producer of bleach creams, pledged to <a href="https://www.forbes.com/sites/jemimamcevoy/2020/06/26/loreal-unilever-reassess-skin-lightening-products-but-wont-quit-the-multi-billion-dollar-market/?sh=5481ae19223a">remove</a> the words “white,” “fair,” and “light” from labels – but it will still manufacture these products. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<p>Some among African countries have moved to <a href="https://www.voanews.com/archive/east-african-countries-move-ban-skin-bleaching-products">ban</a> bleaching creams. The success of the blockbuster film “Black Panther” has likewise sparked a movement celebrating dark skin, with hashtags including #melaninpoppin and #blackgirlmagic. </p>
<p>As I see it, public education and activism on this issue must prevail to protect the health and self-esteem of women of color. The failure of either will only prolong the problem – while sustaining an $8.6 billion bleach cream beauty industry.</p><img src="https://counter.theconversation.com/content/153178/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ronald E. Hall does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fair skin as a beauty ideal underpins the global bleach cream industry – valued at $8.6 billion. There is a nascent backlash against the practice, which endangers health and can perpetuate racism.Ronald E. Hall, Professor of Social Work, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1512022021-02-09T02:28:04Z2021-02-09T02:28:04ZAustralia’s gold industry stamped out mercury pollution — now it’s coal’s turn<figure><img src="https://images.theconversation.com/files/382923/original/file-20210208-21-m28nq5.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C3960%2C1796&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Mercury is a nasty toxin that harms <a href="https://www.who.int/news-room/fact-sheets/detail/mercury-and-health">humans</a> and <a href="https://e360.yale.edu/features/mercurys_silent_toll_on_the_worlds_wildlife">ecosystems</a>.
Most human exposure comes from eating <a href="https://www.scientificamerican.com/article/how-does-mercury-get-into/">contaminated</a> fish and other seafood. But how does mercury enter the Australian environment in the first place?</p>
<p><a href="https://doi.org/10.1525/elementa.2020.070">Our recent research</a> dug into official data and past research to answer this question. </p>
<p>In some rare good news for the environment, it turns out one Australian industry – gold production – has brought mercury emissions down to almost zero. But more can be done about mercury emitted from coal-fired power stations.</p>
<p>Australia is one of the few developed countries yet to ratify the United Nations’ <a href="http://www.mercuryconvention.org/">Minamata Convention on Mercury</a>, which aims to reduce mercury in the environment. But once we deal with emissions from coal burning, we’ll be closer than ever to addressing the problem.</p>
<figure class="align-center ">
<img alt="Salmon chained to a plate" src="https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382925/original/file-20210208-13-1g2l98n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Humans are exposed to mercury via seafood.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Where does mercury pollution come from?</h2>
<p>Mercury is a heavy metal that cycles between the atmosphere, ocean and land. It occurs naturally but can be toxic to humans and wildlife.</p>
<p>Most human-caused mercury emissions come from the burning of <a href="https://www.theguardian.com/australia-news/2018/apr/03/coal-fired-power-stations-caused-surge-in-airborne-mercury-pollution-study-finds">fossil fuels</a> and the mining and production of <a href="https://www.sciencedirect.com/science/article/pii/S1001074217302449?via%3Dihub">gold</a> and other metals. </p>
<p>What’s more, items such as light bulbs and thermometers dumped in landfill can <a href="https://pubs.acs.org/doi/abs/10.1021/es501337j">release mercury</a> 30-50 years later.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-and-overfishing-are-boosting-toxic-mercury-levels-in-fish-122748">Climate change and overfishing are boosting toxic mercury levels in fish</a>
</strong>
</em>
</p>
<hr>
<p>Once in the air, mercury can float around for months, crossing oceans and continents to end up back on the ground, far from where it was emitted. </p>
<p>It’s eventually <a href="https://theconversation.com/plants-safely-store-toxic-mercury-bushfires-and-climate-change-bring-it-back-into-our-environment-129788">taken up</a> by soils, water and plants, then slowly released back to the atmosphere. </p>
<figure class="align-center ">
<img alt="Coal plant emitting steam" src="https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382928/original/file-20210208-21-1ucdkjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coal plants are a major source of mercury emissions.</span>
<span class="attribution"><span class="source">Julian Smith/AAP</span></span>
</figcaption>
</figure>
<h2>A success story</h2>
<p>Estimates vary on the exact amount of mercury that Australian activities release to the air. Studies we reviewed put the figure at anywhere between 8 and 30 tonnes each year.</p>
<p>Our analysis shows the figure is likely at the low end of that range – largely due to a single success story.</p>
<p>In 2006, a gold production facility in Kalgoorlie was thought to cause half of Australia’s industrial mercury emissions. The massive operation includes the Fimiston Open Pit, or “Super Pit”, <a href="https://www.metso.com/showroom/mining/kcgms-emissions-reduction-project-is-a-major-win-for-both-the-environment-and-community/">purportedly</a> so large it can be seen from space.</p>
<p>Gold ore naturally contains mercury. To extract the gold, the ore is typically roasted at temperatures of up to 600°C. During this process, the mercury escapes into the atmosphere. Most mercury pollution from Australia’s gold industry came from a single roaster at the Kalgoorlie site.</p>
<p>But over one decade, mercury emissions from the operation dropped from more than 8 tonnes to just 250 kilograms. This was largely due to a technology upgrade in 2015, when the roaster was <a href="https://www.metso.com/showroom/mining/kcgms-emissions-reduction-project-is-a-major-win-for-both-the-environment-and-community/">replaced</a> by a grinding process.</p>
<p>This success means coal-fired power plants are now Australia’s largest controllable source of mercury emissions. They emit between two and four tonnes of mercury every year (<a href="https://theconversation.com/why-coal-fired-power-stations-need-to-shut-on-health-grounds-68809">along with other air pollutants</a>).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing steady decrease in mercury emissions from 2004 to 2017." src="https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378157/original/file-20210111-19-135mmsu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mercury emissions from two related gold processing facilities in Kalgoorlie, based on data reported to Australia’s National Pollutant Inventory (http://www.npi.gov.au/).</span>
<span class="attribution"><span class="source">Fisher and Nelson, 2020</span></span>
</figcaption>
</figure>
<h2>Other sources of mercury emissions</h2>
<p>Other natural and human activities release mercury into the air. They include:</p>
<p><strong>Bushfires:</strong> Mercury is usually released to the environment <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/gbc.20040">over decades</a>. But the process can be much more rapid if the <a href="https://theconversation.com/mercury-pollution-from-decades-past-may-have-been-re-released-by-tasmanias-bushfires-114603">vegetation burns in a bushfire</a>. </p>
<p>Our research found most estimates of bushfire emissions fall between 4 and 40 tonnes each year. But this work relied on measurements from overseas. <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JD025925">New</a> <a href="https://www.sciencedirect.com/science/article/abs/pii/S1352231018308720">measurements</a> from Australian ecosystems suggests past estimates are probably too high – possibly due to lower mercury concentrations in some Australian vegetation.</p>
<p><strong>Soils and unburnt vegtation:</strong> Only <a href="https://www.sciencedirect.com/science/article/abs/pii/S1352231012007534">one study</a> has calculated the mercury released from Australian soils and unburnt vegetation, which it put at a whopping 74 to 222 tonnes per year.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/plants-safely-store-toxic-mercury-bushfires-and-climate-change-bring-it-back-into-our-environment-129788">Plants safely store toxic mercury. Bushfires and climate change bring it back into our environment</a>
</strong>
</em>
</p>
<hr>
<p>When that research was published in 2012, there were no Australian data to test the model behind these numbers. We still don’t have many measurements, but most <a href="https://www.atmos-chem-phys.net/18/129/2018/">data</a> <a href="https://www.atmos-chem-phys.net/13/5325/2013/">we do have</a> show Australian soils and vegetation take up about as much mercury as they release. </p>
<p>The one exception is “enriched” soils, which contain more mercury than other soils. This is because they are located over natural mineral belts and at former mining sites. At one location in northern New South Wales, enriched soils emitted <a href="https://www.atmos-chem-phys.net/13/5325/2013/">more than 100 times</a> as much mercury as nearby unenriched soils.</p>
<p><strong>Mercury from elsewhere:</strong> Mercury released by other countries can <a href="https://theconversation.com/mercury-from-the-northern-hemisphere-is-ending-up-in-australia-83710">travel to Australia</a> in the air. The levels are tough to quantify, but we are currently using models to produce an estimate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Figure showing the best estimates for Australian mercury sources" src="https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=598&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=598&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378159/original/file-20210111-13-14hsuf2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=598&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Australian atmospheric mercury sources and sinks, in tonnes per year. Current best estimates are shown in black; range from the literature shown in grey. Question marks indicate insufficient data exist to make an informed best estimate. Images courtesy of Tracey Saxby, Kim Kraeer, Lucy Van Essen-Fishman, Diane Kleine via University of Maryland Center for Environmental Science.</span>
<span class="attribution"><span class="source">Fisher and Nelson, 2020</span></span>
</figcaption>
</figure>
<h2>It’s time to act</h2>
<p>Even with our new, lower estimates, Australia’s per capita mercury emissions remain <a href="https://www.amap.no/documents/doc/Technical-Background-Report-for-the-Global-Mercury-Assessment-2013/848">higher than the global average</a>, likely due to our reliance on coal burning. <a href="https://www.abc.net.au/news/science/2019-04-01/coal-fired-power-emissions-mercury/10958128">Technology can lower these emissions</a>.</p>
<p>Some mercury emitted by power plants isn’t in the air for long before it <a href="https://news.umich.edu/fingerprinting-method-tracks-mercury-emissions-from-coal-fired-power-plant/">falls to Earth</a>. This can harm <a href="https://www.mercury-australia.com.au/mercury-in-lake-macquarie-it-is-all-up-in-the-air/">nearby</a> <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422849/">people and ecosystems</a>.</p>
<p>The federal government recently <a href="https://theconversation.com/ban-on-toxic-mercury-looms-in-sugar-cane-farming-but-australia-still-has-a-way-to-go-140596">banned mercury-containing pesticides</a> used in sugar cane farming. With gold production also taken care of, reducing mercury emissions from power plants is the logical next step.</p>
<p>It’s also time for Australia to formally commit to the Minamata Convention. Once we ratify the deal, we’ll be bound to control <a href="https://www.environment.gov.au/protection/chemicals-management/mercury">mercury emissions</a> under international law – and that’s good for humans and wildlife everywhere.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ban-on-toxic-mercury-looms-in-sugar-cane-farming-but-australia-still-has-a-way-to-go-140596">Ban on toxic mercury looms in sugar cane farming, but Australia still has a way to go</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/151202/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jenny Fisher has previously received funding from the Australian Research Council, the Commonwealth Department of Agriculture, Water and the Environment, and the L'Oréal-UNESCO foundation.</span></em></p><p class="fine-print"><em><span>Peter Nelson currently receives funding from UN Environment to investigate aspects of environmental mercury management. He has previously received competitive funding from the Australian Research Council and the CRC program, and from power and resource companies.</span></em></p>Mercury is a nasty toxin that harms humans and ecosystems. The gold and sugar-cane industries have tackled the problem, and it’s time for coal to follow suit.Jenny Fisher, Associate Professor in Atmospheric Chemistry, University of WollongongPeter Nelson, Professor Emeritus of Environmental Studies, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1479722021-01-11T13:14:46Z2021-01-11T13:14:46ZConsumer electronics have changed a lot in 20 years – systems for managing e-waste aren’t keeping up<figure><img src="https://images.theconversation.com/files/376831/original/file-20201231-49872-1uzkolc.jpg?ixlib=rb-1.1.0&rect=17%2C11%2C3864%2C2572&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most of the world's electronics are not recycled, posing health and environmental risks. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/abandoned-and-rusted-laptop-lying-on-riverbed-royalty-free-image/108162816">catscandotcom/Getty Images</a></span></figcaption></figure><p>It’s hard to imagine navigating modern life without a <a href="https://blogs.worldbank.org/opendata/are-cell-phones-becoming-more-popular-toilets">mobile phone</a> in hand. Computers, tablets and smartphones have transformed how we communicate, work, learn, share news and entertain ourselves. They became even more essential when the COVID-19 pandemic moved classes, meetings and social connections online. </p>
<p>But few people realize that our reliance on electronics comes with steep environmental costs, from mining minerals to disposing of used devices. Consumers can’t resist faster products with more storage and better cameras, but constant upgrades have created a <a href="https://time.com/5594380/world-electronic-waste-problem/">growing global waste challenge</a>. In 2019 alone, people discarded <a href="https://www.itu.int/en/ITU-D/Environment/Documents/Toolbox/GEM_2020_def.pdf">53 million metric tons of electronic waste</a>.</p>
<p>In our work as <a href="https://scholar.google.com/citations?user=oZyg9b4AAAAJ&hl=en">sustainability researchers</a>, we study how consumer behavior and technological innovations influence the products that people buy, how long they keep them and <a href="https://scholar.google.com/citations?user=z6q5FZMAAAAJ&hl=en">how these items are reused or recycled</a>. </p>
<p>Our research shows that while e-waste is rising globally, it’s <a href="https://doi.org/10.1111/jiec.13074">declining in the U.S.</a> But some innovations that are slimming down the e-waste stream are also making products harder to repair and recycle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sending electronics to junkyards or landfills wastes an opportunity to recycle valuable materials inside them.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/junkyard-with-old-computer-and-electronic-parts-ca-news-photo/144074229">Joe Sohm/Visions of America /Getty Images</a></span>
</figcaption>
</figure>
<h2>Recycling used electronics</h2>
<p>Thirty years of data show why the volume of e-waste in the U.S. is decreasing. New products are <a href="https://apnews.com/article/bb5ff45b98f64123b3d408dd4a336b59">lighter and more compact than past offerings</a>. Smartphones and laptops have edged out desktop computers. Televisions with thin, flat screens have displaced bulkier <a href="https://en.wikipedia.org/wiki/Cathode-ray_tube">cathode-ray tubes</a>, and streaming services are doing the job that once required standalone MP3, DVD and Blu-ray players. U.S. households now produce about <a href="https://doi.org/10.1111/jiec.13074">10% less electronic waste by weight</a> than they did at their peak in 2015.</p>
<p>The bad news is that <a href="https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling">only about 35% of U.S. e-waste is recycled</a>. Consumers often don’t know where to recycle discarded products. If electronic devices decompose in landfills, hazardous compounds can leach into groundwater, including <a href="https://doi.org/10.1080/10962247.2019.1640807">lead</a> used in older circuit boards, mercury found in early LCD screens and <a href="https://www.aljazeera.com/news/2020/9/30/toxins-in-plastics-blamed-for-health-environment-hazards">flame retardants</a> in plastics. This process poses health risks to people and wildlife. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"809910797182914560"}"></div></p>
<p>There’s a clear need to recycle e-waste, both to protect public health and to recover valuable metals. Electronics contain rare minerals and precious metals mined in socially and ecologically <a href="https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/">vulnerable parts of the world</a>. Reuse and recycling can reduce demand for “<a href="https://www.newsecuritybeat.org/2020/09/companies-struggle-comply-conflict-mineral-reporting-rules/">conflict minerals</a>” and <a href="https://www.weforum.org/agenda/2019/01/how-a-circular-approach-can-turn-e-waste-into-a-golden-opportunity/">create new jobs and revenue streams</a>. </p>
<p>But it’s not a simple process. Disassembling electronics for repair or material recovery is expensive and labor-intensive. </p>
<p>Some recycling companies have illegally <a href="https://resource-recycling.com/e-scrap/2020/12/03/former-president-of-crt-processor-sentenced-to-prison/">stockpiled</a> or <a href="https://resource-recycling.com/e-scrap/2013/08/23/abandoned-warehouses-full-crts-found-several-states/">abandoned</a> e-waste. One Denver warehouse was called “<a href="https://resource-recycling.com/e-scrap/2013/08/23/abandoned-warehouses-full-crts-found-several-states/">an environmental disaster</a>” when 8,000 tons of lead-filled tubes from old TVs were discovered there in 2013. </p>
<p>The U.S. <a href="https://www.pbs.org/newshour/science/america-e-waste-gps-tracker-tells-all-earthfix">exports up to 40% of its e-waste</a>. Some goes to regions such as Southeast Asia that have <a href="https://www.nytimes.com/2019/12/08/world/asia/e-waste-thailand-southeast-asia.html">little environmental oversight and few measures to protect workers</a> who repair or recycle electronics. </p>
<h2>Disassembling products and assembling data</h2>
<p>Health and environmental risks have prompted 25 U.S. states and the District of Columbia to <a href="https://www.ecycleclearinghouse.org/maps.aspx">enact e-waste recycling laws</a>. Some of these measures ban landfilling electronics, while others require manufacturers to support recycling efforts. All of them target large products, like old cathode-ray tube TVs, which contain up to 4 pounds of lead.</p>
<p>We wanted to know whether these laws, adopted from 2003 to 2011, can keep up with the current generation of electronic products. To find out, we needed a better estimate of how much e-waste the U.S. now produces.</p>
<p>We mapped sales of electronic products from the <a href="https://www.theatlantic.com/technology/archive/2014/04/a-terminal-condition/361313/">1950s</a> to the present, using data from industry reports, government sources and consumer surveys. Then we <a href="https://doi.org/10.1038/s41597-020-0573-9">disassembled almost 100 devices</a>, from obsolete VCRs to today’s smartphones and fitness trackers, to weigh and measure the materials they contained.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=197&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=197&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=197&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=248&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=248&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=248&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A researcher takes apart a smartphone to find out what materials are inside.</span>
<span class="attribution"><span class="source">Shahana Althaf</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This dissected tablet shows the components inside, each of which were logged, weighed and measured by researchers.</span>
<span class="attribution"><span class="source">Callie Babbitt</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We created a <a href="https://doi.org/10.5281/zenodo.3986969">computer model to analyze the data</a>, producing one of the most detailed accounts of U.S. electronic product consumption and discards currently available.</p>
<h2>E-waste is leaner, but not necessarily greener</h2>
<p>The big surprise from our research was that U.S. households are <a href="https://doi.org/10.1111/jiec.13074">producing less e-waste</a>, thanks to compact product designs and digital innovation. For example, a smartphone serves as an all-in-one phone, camera, MP3 player and portable navigation system. Flat-panel TVs are about 50% lighter than <a href="https://archive.nytimes.com/www.nytimes.com/gwire/2009/06/15/15greenwire-some-see-e-waste-crisis-trailing-switch-to-dig-81110.html">large-tube TVs</a> and don’t contain any lead. </p>
<p>But not all innovations have been beneficial. To make lightweight products, manufacturers miniaturized components and glued parts together, making it harder to repair devices and more expensive to recycle them. <a href="https://doi.org/10.1007/s10098-020-01890-3">Lithium-ion batteries</a> pose another problem: They are hard to detect and remove, and they can spark <a href="https://www.theverge.com/2020/2/28/21156477/recycling-plants-fire-batteries-rechargeable-smartphone-lithium-ion">disastrous fires</a> during transportation or recycling.</p>
<p>Popular features that consumers love – speed, sharp images, responsive touch screens and long battery life – rely on metals like cobalt, indium and <a href="https://theconversation.com/what-are-rare-earths-crucial-elements-in-modern-technology-4-questions-answered-101364">rare-earth elements</a> that require immense energy and expense to mine. Commercial recycling technology cannot yet recover them profitably, although innovations are starting to emerge. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Apple’s new robot, Daisy, can disassemble nine different iPhone models to recover valuable materials that traditional recyclers cannot.</span>
<span class="attribution"><a class="source" href="https://www.apple.com/newsroom/2018/04/apple-adds-earth-day-donations-to-trade-in-and-recycling-program/">Apple</a></span>
</figcaption>
</figure>
<h2>Reenvisioning waste as a resource</h2>
<p>We believe solving these challenges requires a <a href="https://doi.org/10.1016/j.resconrec.2019.05.038">proactive approach</a> that treats digital discards as resources, not waste. Gold, silver, palladium and other valuable materials are now more concentrated in e-waste than in natural ores in the ground. </p>
<p>“<a href="https://www.bbc.com/future/article/20200407-urban-mining-how-your-home-may-be-a-gold-mine">Urban mining</a>,” in the form of recycling e-waste, could replace the need to dig up scarce metals, reducing environmental damage. It would also <a href="https://doi.org/10.1016/j.resconrec.2020.105248">reduce U.S. dependence</a> on <a href="https://www.cato.org/blog/chinas-critical-minerals-national-security-meaning-supply-chain-interdependence">minerals imported from other countries</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=245&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=245&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=245&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=308&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=308&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=308&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Concentration of hazardous (left) and valuable (right) materials within the U.S. e-waste stream.</span>
<span class="attribution"><span class="source">Althaf et al. 2020</span></span>
</figcaption>
</figure>
<p>Government, industry and consumers all have roles to play. Progress will require designing products that are <a href="https://www.ifixit.com/">easier to repair</a> and reuse, and persuading consumers to <a href="https://earth911.com/eco-tech/ways-to-reuse-old-laptop/">keep their devices longer</a>. </p>
<p>We also see a need for responsive e-waste laws in place of today’s dated patchwork of state regulations. Establishing <a href="https://knowledge.wharton.upenn.edu/article/how-u-s-laws-do-and-dont-support-e-recycling-and-reuse/">convenient</a>, <a href="https://sustainableelectronics.org/recyclers">certified</a> <a href="https://e-stewards.org/">recycling locations</a> can keep more electronics out of landfills. With retooled operations, recyclers can recover more valuable materials from the e-waste stream. Steps like these can help balance our reliance on electronic devices with systems that better protect human health and the environment. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/147972/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Callie Babbitt receives funding from the National Science Foundation, the Consumer Technology Association, and the Staples Sustainable Innovation Lab.</span></em></p><p class="fine-print"><em><span>Shahana Althaf received funding from the National Science Foundation, the Consumer Technology Association, and the Staples Sustainable Innovation Lab.</span></em></p>Technical advances are reducing the volume of e-waste generated in the US as lighter, more compact products enter the market. But those goods can be harder to reuse and recycle.Callie Babbitt, Associate Professor of Sustainability, Rochester Institute of TechnologyShahana Althaf, Postdoctoral associate, Yale UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1405962020-06-21T20:07:48Z2020-06-21T20:07:48ZBan on toxic mercury looms in sugar cane farming, but Australia still has a way to go<figure><img src="https://images.theconversation.com/files/342920/original/file-20200619-70386-o94vpv.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Phil / CC BY (https://creativecommons.org/licenses/by/2.0)</span></span></figcaption></figure><p>This month, federal authorities finally announced an upcoming <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">ban on mercury-containing pesticide</a> in Australia. We are one of the last countries in the world to do so, despite <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2366450/">overwhelming evidence</a> over more than 60 years that mercury use as fungicide in agriculture is dangerous.</p>
<p>Mercury is a toxic element that damages human health and the environment, even in low concentrations. In humans, mercury exposure is <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">associated with</a> problems such as kidney damage, neurological impairment and delayed cognitive development in children.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-emits-mercury-at-double-the-global-average-82577">Australia emits mercury at double the global average</a>
</strong>
</em>
</p>
<hr>
<p>The ban will prevent about <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">5,280 kilograms of mercury</a> entering the Australian environment each year.</p>
<p>But Australia is yet to ratify an international treaty to reduce mercury emissions from other sources, such as the dental industry and coal-fired power stations. This is our next challenge.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Prime Minister Scott Morrison visiting a sugar cane farm in 2019. Mercury-containing pesticides will be banned.</span>
<span class="attribution"><span class="source">Cameron Laird/AAP</span></span>
</figcaption>
</figure>
<h2>A mercury disaster</h2>
<p>Mercury became a popular pesticide ingredient for agriculture in the early 1900s, and a number of poisoning events ensued throughout the world. </p>
<p>They include the <a href="https://www.researchgate.net/publication/330958073_1971_Iraq_Poison_Grain_Disaster_and_Methylmercury_Hawraz">Iraq grain disaster</a> in 1971-72, when grain seed treated with mercury was imported from Mexico and the United States. The seed was not meant for human consumption, but rural communities used it to make bread, and 459 people died. </p>
<p>In the decades since, most countries have banned the production and/or use of mercury-based pesticides on crops. <a href="https://apvma.gov.au/node/12591">In 1995</a> Australia discontinued their use in most applications, such as turf farming.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Emissions of the element mercury are a threat to human health and the environment.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Hydrargyrum.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Despite this, authorities exempted a fungicide containing mercury known as Shirtan. They <a href="http://classic.austlii.edu.au/au/journals/PrecedentAULA/2005/56.pdf">restricted</a> its use to sugar cane farming in Queensland, New South Wales, Western Australia and the Northern Territory.</p>
<p><a href="http://www.canegrowers.com.au/page/advocacy/key-issues/environment">According to</a> the sugar cane industry, about 80% of growers use Shirtan to treat pineapple sett rot disease.</p>
<p>But this month, the Australian Pesticides and Veterinary Medicines Authority <a href="https://apvma.gov.au/sites/default/files/gazette_02062020.pdf">cancelled the approval</a> of the mercury-containing active ingredient in Shirtan, methoxyethylmercuric chloride. The decision was made at the request of the ingredient’s manufacturer, Alpha Chemicals. </p>
<p>Shirtan’s <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">registration</a> was cancelled last week. It will no longer be produced in Australia, but existing supplies can be sold to, and used by, sugar cane farmers for the next year until it is fully banned.</p>
<h2>Workers and nature at risk</h2>
<p>Over the past 25 years, Australia’s continued use of Shirtan allowed <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">about 50,000 kilograms of mercury</a> into the environment. The effect on river and reef ecosystems is largely unknown. </p>
<p>What is known is that mercury can be toxic even at very low concentrations, and research is needed to understand its ecological impacts.</p>
<p>The use of mercury-based pesticide has also created a high risk of exposure for sugar cane workers. At most risk are those not familiar with safety procedures for handling toxic materials, and who may have been poorly supervised. This risk has been exacerbated by the use itinerant workers, particularly those from a non-English speaking background. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=321&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=321&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=321&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=403&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=403&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=403&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">South Sea Islanders hoeing a cane field in Queensland, 1902. Cane workers have long been exposed to mercury.</span>
<span class="attribution"><span class="source">State Library of Queensland</span></span>
</figcaption>
</figure>
<p>Further, in the hot and humid conditions of Northern Australia, it has been reported that workers may have removed protective gloves <a href="http://classic.austlii.edu.au/au/journals/PrecedentAULA/2005/56.pdf">to avoid sweating</a>. Again, research is needed to determine the implication of these practices for human health. </p>
<p>To this end, <a href="https://www.mercury-australia.com.au/">Mercury Australia</a>, a multi-disciplinary network of researchers, has formed to address the environmental, health and other issues surrounding mercury use, both contemporary and historical.</p>
<h2>Australia is yet to ratify</h2>
<p>The <a href="http://www.mercuryconvention.org/">Minamata Convention on Mercury</a> is a global treaty to control mercury use and release into the environment. Australia signed onto the convention in 2013 but is yet to ratify it. </p>
<p>Until the treaty is ratified, Australia is not legally bound to its obligations. It also places us at odds with <a href="http://www.mercuryconvention.org/Countries/Parties/tabid/3428/language/en-US/Default.aspx">more than 100 countries that have ratified it</a>, including many of Australia’s developed-nation counterparts.</p>
<p>Australia’s outlier status in this area is shown in the below table:</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=156&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=156&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=156&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=196&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=196&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=196&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Accession, acceptance or ratification have the same legal effect, where parties follow legal obligations under international law.</span>
</figcaption>
</figure>
<p>Mercury-based pesticide use was one of Australia’s largest sources of mercury emissions. But if Australia ratifies the convention, it would <a href="https://www.environment.gov.au/system/files/resources/c350c1c3-a14f-4bde-acfc-267bfd49f6e9/files/minamata-convention-mercury-pesticides-factsheet.pdf">be required to</a> control other sources of mercury emissions, such as <a href="https://www.environment.gov.au/protection/publications/minamata-convention-mercury-dental-fs">dental amalgam</a> and the <a href="http://www.mercuryconvention.org/Portals/11/documents/publications/BAT_BEP_E_interractif.pdf">burning of coal in power stations</a>.</p>
<p>The three active power stations in the Latrobe Valley, for example, together emit <a href="http://www.npi.gov.au/npidata/action/load/facility-source-result/criteria/lga/432/destination/ALL/source-type/ALL/substance-name/All/subthreshold-data/Yes/year/2019?pageIndex=1&sort=regBusinessName&dir=asc&pageSize=10">about 1,200 kilograms of mercury each year</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=362&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=362&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=362&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=455&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=455&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=455&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The coal-burning Mount Piper Power station near Lithgow in NSW. Government efforts to reduce mercury emissions should focus on coal plants.</span>
<span class="attribution"><span class="source">David Gray/Reuters</span></span>
</figcaption>
</figure>
<h2>Time to look at coal</h2>
<p>If Australia ratified the Minamata Convention, it would provide impetus for a timely review and, if necessary, update of mercury regulations across Australia.</p>
<p>Emissions from coal-fired power stations in Australia are regulated by the states through pollution control licences. Some states would likely have to amend these licences if Australia ratified the convention. For example, Victorian licences for coal-fired power stations currently do not include <a href="https://www.dea.org.au/wp-content/uploads/2018/02/VIC-Brown-coal-fired-power-stations-licence-reviews-submission---02-18.pdf">limits on mercury emissions</a>. </p>
<p>Pollution control technologies were introduced at Australian coal plants in the early 1990s. But they <a href="https://www.theguardian.com/environment/2017/aug/15/australian-coal-power-pollution-would-be-illegal-in-us-europe-and-china-report">do not match state-of-the-art technologies applied to coal plants in North America and Europe</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-wont-australia-ratify-an-international-deal-to-cut-mercury-pollution-68820">Why won't Australia ratify an international deal to cut mercury pollution?</a>
</strong>
</em>
</p>
<hr>
<p>Australian environment authorities have been <a href="https://www.environment.gov.au/protection/chemicals-management/mercury">examining the implications</a> of ratifying the convention. But progress is slow.</p>
<p>The issue of mercury emissions does not attract significant public or political attention. But there is a <a href="https://www.unenvironment.org/resources/publication/global-mercury-assessment-2018">global scientific consensus</a> that coordinated international action is needed.</p>
<p>The <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">pesticide phase-out</a> and ban is an important step. But Australia still has a way to go.</p><img src="https://counter.theconversation.com/content/140596/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Larissa Schneider receives funding from the Australian Research Council. She is member of the Mercury Australia research network. </span></em></p><p class="fine-print"><em><span>Cameron Holley receives funding from the Australian Research Council. He is a member of the Mercury Australia research network.</span></em></p><p class="fine-print"><em><span>Darren Sinclair receives funding receives funding from the Australian Research Council. He is a member of the Mercury Australia research network.</span></em></p><p class="fine-print"><em><span>Simon Haberle receives funding from the Australian Research Council. He is member of the Mercury Australia research network.</span></em></p>Australia has failed to ratify an international treaty to reduce harmful mercury emissions. Mercury exposure can cause kidney damage and brain impairment, especially in children.Larissa Schneider, DECRA fellow, Australian National UniversityCameron Holley, Professor, UNSW SydneyDarren Sinclair, Professor, University of CanberraSimon Haberle, Professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1390122020-06-17T11:19:18Z2020-06-17T11:19:18ZHealthier food can contain more contaminants – but there’s a simple way to stay safe<figure><img src="https://images.theconversation.com/files/342543/original/file-20200617-94070-1q0vkn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/food-storage-wooden-shelf-pantry-grain-1681776787">VH Studio/Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.sciencedirect.com/science/article/pii/S0147651320304401">recent study</a> found that brown and organic rice sold in the UK tends to contain significantly more arsenic than white non-organic varieties that are often considered less healthy. Arsenic is found in many foods but can be <a href="https://www.nutrition.org.uk/nutritioninthenews/headlines/arsenicinrice.html?__cf_chl_jschl_tk__=0cfff5cc20203fef57a7f0abe9b1a85152aed58b-1589892797-0-AYmZvmOiiv_74fZJJSryyTnFV43AyehQhet-M_4bgSLRRtAqwafR-5tsQaItVhiyTkpgyDWu4qNaiojRSeuyPNVCq0VsAgXAXN8rlR8qz_OMY5jERQC1Cdjad7JMzUexYlUSTojatdc993jz4re95-qcfjTmRx-sdIdENyvshMVwv-lczOfB2175XG57sesDjGYzcSm7j8g93zoItYbUInGTxPQIpZu_kh_BifQ3fu2ZkfsNRlnyZWGtJ0mn36PLb3SdarTfEQ8YnIrrvsDPPbLDRCPO4nZ827AsYOJczhc0HYFSKfCZig15Qzu-h_5fy66oVjfqfUycswAdV1a56EywEzGBQqyj4fnIzQDR1DehECYlOBxWNT_kLYmunTEU0bduR-UtNTpreqBbVuGQ3-0">especially concentrated in rice</a>, particularly in the outer layers, which are removed to produce white rice but retained in brown rice.</p>
<p>Consuming too much arsenic over a long period is thought to be dangerous because it can cause cancer. Yet brown rice is usually considered healthier than white because of the extra fibre and vitamins it contains. Organic rice is less likely to have been exposed to pesticides. </p>
<p>Ascertaining exactly what a healthy diet consists of can be full of these apparent paradoxes. Should you eat brown rice for the fibre or white rice for the lower arsenic levels? The answer shows the potential difficulties of using studies like the one cited above to guide dietary choices and the need to fully understand the complexities of nutrition and dietary choices. </p>
<h2>Arsenic in rice</h2>
<p>For adults, the reality is that even eating one kilogram of cooked brown rice a day is <a href="https://pubmed.ncbi.nlm.nih.gov/18448219/">unlikely to cause</a> the consumption of too much arsenic. Also because brown rice <a href="https://www.bda.uk.com/resourceDetail/printPdf/?resource=wholegrains">is a wholegrain</a>, eating it will also supply you with more fibre (a nutrient very few UK adults reach the recommended 30g per day of), as well as wide range of vitamins, minerals and essential fatty acids.</p>
<p>Children under five are more at risk of consuming too much arsenic from rice but a varied diet and <a href="https://www.food.gov.uk/safety-hygiene/arsenic-in-rice">avoiding rice drinks</a> should mitigate this. You can also reduce arsenic in rice by up to 80% by rinsing it and cooking it in copious amounts of water.</p>
<h2>Mercury in fish</h2>
<p>Some varieties of fish can also contain significant amounts of mercury, specifically methylmercury, which can be toxic to humans, causing kidney damage and affecting foetal and infant brain development. Levels of methylmercury can be particularly high in fish that eat other fish, such as shark, swordfish, marlin and tuna.</p>
<p>The <a href="https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2015.3982">European Food Safety Authority</a> says up to 1.3 micrograms of methylmercury per kg of bodyweight per week is a safe amount. For a typical 90kg adult that equals 117mcg a week. The amount of methylmercury in a single portion of fish in this category can vary hugely but EU rules mean 1kg should contain no more than 500mcg.</p>
<p>For the most commonly eaten type of fish in this category, tinned tuna, a 100g drained tin could contain as much as 50mcg of methyl mercury. So eating more than two tins a week could theoretically put you at greater risk. Shark, swordish and marlin tend to contain more mercury so more caution is advised here, and you should avoid them <a href="https://www.nhs.uk/common-health-questions/pregnancy/should-pregnant-and-breastfeeding-women-avoid-some-types-of-fish">if you are pregnant</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342544/original/file-20200617-94049-1glqe6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You’d have to eat a lot of tuna to be harmed by its mercury content.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/food-storage-wooden-shelf-pantry-grain-1681776787">HandmadePictures/Shutterstock</a></span>
</figcaption>
</figure>
<p>But most tins of tuna aren’t likely to contain the maximum allowed amount of mercury and reports of bodybuilders and other tuna enthusiasts becoming ill with mercury poisoning are rare.</p>
<p>Meanwhile, fish <a href="https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/oily-fish?gclid=Cj0KCQjwzZj2BRDVARIsABs3l9IH1K15bUbc8ol3nAJF0QIr0AeKkPiM7SqZ5oVLeQy__nKsO0DmU5caAqpBEALw_wcB&gclsrc=aw.ds">contributes to a healthy</a> Mediterranean-style diet linked to lower chances of type 2 diabetes, high blood pressure and raised cholesterol. Oily fish (such as sardines, mackerel, salmon, trout or herring) are particularly beneficial in this respect and contain nutrients important for foetal and early infancy brain development. So most adults who eat fish <a href="https://www.nhs.uk/live-well/eat-well/fish-and-shellfish-nutrition/">are advised to aim</a> for at least two portions a week including at least one type of oily fish.</p>
<h2>Pesticides in vegetable skins</h2>
<p>It’s well established that the peels and skins of fruit and vegetables are an important source of fibre, helping to <a href="https://journals.rcni.com/nursing-standard/evidence-and-practice/understanding-the-role-of-carbohydrates-in-optimal-nutrition-ns.2019.e11323/print/abs">maintain digestive health</a> and control blood glucose levels. These outer layers also <a href="https://www.bda.uk.com/uploads/assets/622d08b0-c391-4b50-a7e9eeac006f354a/Fruit-Veg-food-fact-sheet.pdf">tend to contain</a> more vitamin C, minerals and other beneficial “phenolic” compounds than the flesh. </p>
<p>But there is <a href="https://www.pan-uk.org/our-food">also some concern</a> that pesticides used to treat seeds, growing plants or harvested crops can collect in particularly high concentrations in skins, although the actual amounts vary hugely. <a href="https://www.theverge.com/2017/10/26/16553942/apples-wash-pesticides-baking-soda-chemicals-organic-peel-fruit">Some people argue</a> you should peel your fruits and vegetables as a result.</p>
<p>But the actual amounts of pesticide residue that can be found in fruit and veg is limited. The UK government’s <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/879216/prif-monitoring-2019-quarter3.pdf">most recent research</a> on the issue only found samples that exceeded the maximum legal pesticide residue level in a small number of samples in four out of 14 types of fruit and vegetables tested.</p>
<p>The <a href="https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food">World Health Organization</a> says: “None of the pesticides that are authorised for use on food in international trade today are genotoxic” (damaging to DNA, which can cause mutations or cancer). </p>
<p>Someone with a healthy or high bodyweight and/or a varied diet is very unlikely to be exposed to enough pesticide to breach this level. In contrast, the evidence for the benefits of eating fruits and vegetables including the skins is overwhelming. So it still seems prudent that we eat as much as we can and, where possible and palatable, consume the skins. </p>
<p>These examples underline why the “everything in moderation” we often see in <a href="https://www.nhs.uk/live-well/eat-well/the-eatwell-guide/">healthy eating guidelines</a> really does seem to be the best approach. The more types of food we eat, the less of each we consume and therefore we can reduce the chance of doing ourselves harm from either too much or too little of something. But knowing what the safe limits are can help answer some of the more difficult questions about what’s the best food choice.</p><img src="https://counter.theconversation.com/content/139012/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ruth Fairchild does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new study shows high-fibre brown rice also contains more arsenic than white rice – so which is better for you?Ruth Fairchild, Senior Lecturer in Nutrition, Cardiff Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1333242020-05-28T12:15:53Z2020-05-28T12:15:53ZGold rush, mercury legacy: Small-scale mining for gold has produced long-lasting toxic pollution, from 1860s California to modern Peru<figure><img src="https://images.theconversation.com/files/332060/original/file-20200501-42908-1p78mn.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3000%2C1754&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artisanal small-scale gold mining polluted this stream and deforested sections of the Madre de Dios area of Peru. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/miner-walks-through-a-polluted-stream-in-a-deforested-area-news-photo/450562169?adppopup=true">Mario Tama/Getty Images</a></span></figcaption></figure><p>Gold is everywhere in modern life, from jewelry to electronics to smartphones. The global electronics industry alone uses <a href="https://doi.org/10.1007/s13404-014-0151-z">280 tons</a> annually. And that demand keeps growing. </p>
<p>But most people know little about the environmental impacts of gold mining. About 15% of world gold production is from <a href="https://web.unep.org/globalmercurypartnership/our-work/artisanal-and-small-scale-gold-mining-asgm">artisanal and small-scale mining</a> in over 70 countries throughout Asia, Africa and South America. These operations employ <a href="http://dx.doi.org/10.1002/chem.201704840">10 to 19 million workers</a>. They often are poorly policed and weakly regulated.</p>
<p>Artisanal mining might sound quaint, but it is usually criminal activity and results in widespread environmental damage. It also is the <a href="https://www.unenvironment.org/explore-topics/chemicals-waste/what-we-do/mercury/global-mercury-assessment">largest source of mercury pollution in the world today</a>, far exceeding other activities such as coal combustion and cement manufacturing. While mercury is an element that occurs naturally in the Earth’s crust, it has <a href="https://www.who.int/news-room/fact-sheets/detail/mercury-and-health">many toxic effects</a> on humans and animals, even at very low exposure levels.</p>
<p>We have studied <a href="https://docs.google.com/document/d/1SfOGYUrkdvDIY2Xjo70L84q02EmDLQ8VwPjFQ9WObbk/edit">mercury pollution from artisanal gold mining</a> for the past five years. The extraction methods that these operations use today are not drastically different from processes that miners employed in the California gold rush in the mid-1800s. Today we see history repeating itself in places like the Peruvian Amazon, where small-scale gold mining threatens to leave behind long-lasting social, economic and environmental consequences. </p>
<p><iframe id="ULv9b" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/ULv9b/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Mercury contamination from gold mining</h2>
<p>Mercury has been used for centuries as an inexpensive and easy way to collect gold. The process begins when miners pump a mixture of water and sediment from a riverbed into a trough, where the sediment can be suspended into a slurry – a technique known as hydraulic mining.</p>
<p>Next they add mercury, which binds to the gold particles, forming an amalgam. Mercury is heavier than pure gold, so the balls of amalgam sink to the bottom of buckets or holding ponds where they can be collected. Finally, workers burn off the mercury – often with a hand torch or in a crude stove – leaving gold metal behind. </p>
<p>This process releases mercury to the environment in two forms. First, tailings, or waste material, can contaminate nearby land and <a href="http://doi.org/10.1525/elementa.274">aquatic ecosystems</a>. Second, mercury vapor enters the atmosphere and can <a href="http://dx.doi.org/10.1289/ehp.120-a424">travel long distances</a> before being deposited to land and water via rainfall or small dust particles.</p>
<p>In the environment, microbes can transform mercury into a more potent form known as methylmercury. Methylmercury can be taken up by bacteria, plankton and other microorganisms that are then consumed by fish and build up to dangerous concentrations in animals higher on the food chain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/326121/original/file-20200407-74220-17ujdhe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">When artisanal gold miners burn mercury, it is released into the atmosphere and can end up on land or in water. Mining tailings (solid waste) also deposit mercury onto land or into water. Microbes in the environment can convert mercury into methylmercury, which can be taken up by living organisms, including fish and people.</span>
<span class="attribution"><span class="source">Arianna Agostini, Rand Alotaibi, Arabella Chen, Annie Lee, Fernanda Machicao, Melissa Marchese</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Methylmercury is a potent neurotoxin that is harmful to humans and wildlife, such as <a href="https://www.semanticscholar.org/paper/Giant-otter-(Pteronura-brasiliensis)-at-risk-Total-Gutleb-Schenck/a87fd7789293a03e480d58cb237db50a3a587239">endangered giant otters</a> that feed high on the food web within these contaminated environments. It can cause severe central nervous system damage that results in sensory and motor deficits, as well as behavioral impairments such as difficulty swimming in aquatic animals and <a href="https://doi.org/10.1007/398_2017_4">flying</a> in birds.</p>
<h2>A lasting legacy in California</h2>
<p>During the U.S. gold rush, <a href="https://www.nationalgeographic.org/article/after-gold-rush/">hydraulic mining operations in California</a> completely denuded forested landscapes, altered the course of rivers, increased sedimentation that clogged river beds and lakes and released enormous amounts of mercury onto the landscape. California wildcat miners used an estimated <a href="https://pubs.usgs.gov/fs/2005/3014/fs2005_3014_v1.1.pdf">10 million pounds</a> of mercury from the 1860s through the early 1900s. Most of it was released to the environment as tailings and mercury vapor. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337113/original/file-20200522-124860-1nesdny.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Panning for gold in California, 1850.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/0/04/1850_Woman_and_Men_in_California_Gold_Rush.jpg">Unknown/Wikipedia</a></span>
</figcaption>
</figure>
<p>A century later, water, soil and sediments in the Sierra Nevada region still have <a href="https://doi.org/10.1007/s002540050153">high concentrations</a> of mercury and methylmercury, often exceeding thresholds set by the U.S. Environmental Protection Agency. Studies show that <a href="https://doi.org/10.1007/s10661-009-0836-6">fish</a>, birds and other organisms living near historically mined sites in California have high mercury concentrations in their bodies compared to those inhabiting nearby unmined landscapes. Extreme erosion on mountain slopes can continuously mobilize <a href="http://dx.doi.org/10.1525/elementa.333">mercury deposited decades ago</a>. </p>
<h2>History repeats itself</h2>
<p>Like men who traveled to California in 1849 hoping to strike it rich, today’s artisanal miners around the world are mainly low-skilled workers hoping to support themselves and their families. </p>
<p>In Peru, where we have studied this process, artisanal miners produce an estimated <a href="https://www.responsiblemines.org/wp-content/uploads/2018/05/Case_Study_Peru_June_2012.pdf">35,000 to 40,000 pounds</a> of gold per year. The industry offers an opportunity for upward mobility for <a href="https://www.smithsonianmag.com/travel/the-devastating-costs-of-the-amazon-gold-rush-19365506/">substantial numbers of Peruvians</a>, who generally migrate to mining sites from coastal and mountain towns.</p>
<p>As a result, gold rush towns have boomed over the past 20 years. The <a href="https://en.wikipedia.org/wiki/Interoceanic_Highway">Inter-Oceanic Highway</a>, which was completed in 2012 and runs from Brazil’s Atlantic coast to Peru’s Pacific coast, has connected these towns to larger cities and increased access to the Peruvian Amazon.</p>
<p>Producing a pound of gold requires about 6 pounds of mercury. Given that at least 50% of the mercury used in these operations is lost to the environment, we estimate that artisanal gold mining in Peru alone releases nearly 50,000 pounds of mercury annually.</p>
<p>Mining in this region is producing impacts that are strikingly similar to the hallmarks of the California gold rush. For example, miners in the Peruvian Amazon have cleared more than <a href="https://doi.org/10.3390/rs10121903">250,000 acres of forest</a> since 1984.</p>
<p>The Madre de Dios River, which runs through a zone that has seen substantial mining, will likely continue to erode the landscape, carrying mercury-laden particles downstream. Long-lasting mercury contamination in this region threatens the <a href="https://www.worldbank.org/en/news/feature/2019/05/22/why-the-amazons-biodiversity-is-critical-for-the-globe">highest biodiversity on the planet</a> and many indigenous communities. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337972/original/file-20200527-20229-arfmw9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comparison of landscape change from gold mining during the California gold rush (left) and modern artisanal mining in Peru (right).</span>
<span class="attribution"><span class="source">Bancroft Library, UC Berkeley (left); Arabella Chen (right)</span></span>
</figcaption>
</figure>
<p>Gold mining in 19th-century California <a href="https://americanexperience.si.edu/wp-content/uploads/2015/02/The-Gold-Rush-and-Westward-Expansion.pdf">sparked a wave of western migration</a> and helped drive settlement of what we now refer to as the western United States at a time when mining and environmental pollution were unregulated. Today, use of mercury in artisanal gold mining is regulated by the 2013 <a href="https://2009-2017.state.gov/e/oes/eqt/chemicalpollution/mercury/245187.htm">Minamata Convention on Mercury</a>, which has been signed by 128 countries – including Peru. Yet there is little on-the-ground regulation in most countries. Nor have governments addressed legacy pollution and deforestation from gold mining. </p>
<p>Illegal artisanal gold mining is a major source of income for local communities in places like the Madre de Dios region of Peru. As long as people all over the world continue to demand more gold, we believe that they are just as responsible as miners and local policymakers for the environmental degradation gold mining causes.</p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>.]</p><img src="https://counter.theconversation.com/content/133324/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacqueline Gerson receives funding from Duke University Bass Connections, Duke University Global Health Institute, Duke University Center for Latin American and Caribbean Studies, Duke University Center for International and Global Studies, Duke University Dissertation Graduate School, Geological Society of America, Josiah Charles Trent Memorial Foundation Endowment Fund, Lewis and Clark Fund for Exploration and Field Research, and National Science Foundation Graduate Research Fellowship. </span></em></p><p class="fine-print"><em><span>Austin Wadle is affiliated with Service Employees International Union Local 27 as the cochair of the Duke Graduate Students Union. Austin Wadle receives funding from Duke University Scholars Program. </span></em></p><p class="fine-print"><em><span>Jasmine Parham receives funding from Duke University Center for Latin American and Caribbean Studies, and the Duke University Biology Department. </span></em></p>Small-scale gold mining operations in developing countries are major sources of toxic mercury pollution, using techniques that haven’t changed much since the California Gold Rush 150 years ago.Jacqueline Gerson, Ph.D. Candidate in Ecology, Duke UniversityAustin Wadle, Ph.D. Student in Civil and Environmental Engineering, Duke UniversityJasmine Parham, Ph.D. Student in Biology, Duke UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1323752020-03-05T14:20:42Z2020-03-05T14:20:42ZThere’s a complex history of skin lighteners in Africa and beyond<figure><img src="https://images.theconversation.com/files/317538/original/file-20200227-24680-l3fa2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Detail of book cover</span> <span class="attribution"><span class="source">Wits University Press</span></span></figcaption></figure><p>Somali-American activists recently scored a victory against Amazon and against <a href="https://www.theguardian.com/commentisfree/2019/oct/09/colourism-is-finally-being-taken-seriously-thanks-to-celebrities-like-lupita-nyongo">colourism</a>, which is prejudice based on preference for people with lighter skin tones. Members of the non-profit <a href="http://thebeautywell.org/">The Beautywell Project</a> teamed up with the <a href="https://www.sierraclub.org/">Sierra Club</a> to convince the online retail giant to stop selling skin lightening products that contain <a href="https://www.thoughtco.com/mercury-element-facts-608433">mercury</a>.</p>
<p>After more than a year of protests, this coalition of antiracist, health, and environmental activists <a href="https://www.mprnews.org/story/2019/11/22/amazon-pulls-skinlightening-creams-from-site-after-demands-from-minnesota-activists">persuaded Amazon</a> to remove some 15 products containing <a href="https://www.zeromercury.org/">toxic levels of mercury</a>. This puts a small but noteworthy dent in the global trade in skin lighteners, estimated to reach US$31.2 billion by 2024.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/318031/original/file-20200302-18283-k3bdh0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Amira Adawe, an activist with The Beautywell Project pickets outside Amazon.</span>
<span class="attribution"><span class="source">Amira Adawe</span></span>
</figcaption>
</figure>
<p>What are the roots of this sizeable trade? And how might its most toxic elements be curtailed?</p>
<p>The online sale of skin lighteners is relatively new, but the in-person traffic is very old. My new <a href="https://www.dukeupress.edu/beneath-the-surface">book</a> explores this layered history from the vantage point of South Africa.</p>
<p>As in other parts of the world colonised by European powers, the politics of skin colour in South Africa have been importantly shaped by the <a href="https://www.sahistory.org.za/article/history-apartheid-south-africa">history</a> of white supremacy and institutions of racial slavery, colonialism, and segregation. My book examines that history.</p>
<p>Yet, racism alone cannot explain skin lightening practices. My book also attends to intersecting dynamics of class and gender, changing beauty ideals and the expansion of consumer capitalism.</p>
<h2>A deep history of skin whitening and lightening</h2>
<p>For centuries and even millennia, elites used paints and powders to create smoother, paler appearances, unblemished by illness and the sun’s darkening and roughening effects.</p>
<p>Cosmetic users in ancient Mesopotamia, Egypt, Greece, and Rome created dramatic appearances by pairing skin whiteners containing lead or chalk with black eye makeup and red lip colourants. In China and Japan too, elite women and some men used white lead preparations and rice powder to achieve complexions resembling white jade or fresh lychee.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1079&fit=crop&dpr=1 600w, https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1079&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1079&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1356&fit=crop&dpr=1 754w, https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1356&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/318048/original/file-20200302-18308-t3ibht.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1356&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In this 1623 portrait by Anthony van Dyck, Elena Grimaldi’s regal whiteness is underscored by a dark-toned servant.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>Skin lighteners generate a less painted look than skin whiteners by removing rather than concealing blemished or melanin-rich skin. <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/melanin">Melanin</a> is the biochemical compound that makes skin colourful.</p>
<p>Active ingredients in skin lighteners have ranged from acidic compounds like lemon juice and milk to harsher chemicals like sulfur, arsenic, and mercury. In parts of precolonial Southern Africa, some people used mineral and botanical preparations to brighten – rather than whiten or lighten – their skin and hair.</p>
<p>During the era of the <a href="http://www.unesco.org/new/en/social-and-human-sciences/themes/slave-route/transatlantic-slave-trade/">trans-Atlantic slave trade</a>, skin colour and associated physical difference were used to distinguish enslaved people from free, and to justify the former’s oppression. Colonisers cast melanin-rich hues as the embodiment of ugliness and inferiority. Within this racist political order, some sought to whiten and lighten their complexions.</p>
<p>By the twentieth century, mass-produced skin lightening creams ranked among the world’s most popular cosmetics. Consumers included white, black, and brown women.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=756&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=756&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=756&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=950&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=950&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317436/original/file-20200226-24690-8e4tu1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=950&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This ad appeared in an issue of the Central and East African edition of Drum magazine.</span>
<span class="attribution"><span class="source">Duke University Press</span></span>
</figcaption>
</figure>
<p>In the 1920s and 1930s, many white consumers swapped skin lighteners for tanning lotions as time spent sunbathing and playing outdoors became a sign of a healthy and leisured lifestyle. <a href="https://www.theguardian.com/commentisfree/2012/feb/19/history-of-tanning">Seasonal tanning</a> embodied new forms of white privilege.</p>
<p>Skin lighteners became primarily associated with people of colour. For black and brown consumers, living in places like the United States and South Africa where racism and colourism have flourished, even slight differences in skin colour could carry political and social consequences.</p>
<h2>The mercury effect</h2>
<p>Skin lighteners can be physically harmful. Mercury, one of their most common active ingredients, lightens skin in two ways. It inhibits the formation of melanin by rendering the enzyme <a href="https://www.ncbi.nlm.nih.gov/pubmed/8496620">tyrosinase</a> inactive; and it exfoliates the tanned, outer layers of the skin through the production of <a href="https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochloric-acid">hydrochloric acid</a>.</p>
<p>By the early twentieth century, pharmaceutical and medical textbooks recommended mercury – usually in the form of ammoniated mercury – for treating skin infections and dark spots while often warning of its harmful effects. Cosmetic manufacturers marketed creams containing ammoniated mercury as “freckle removers” or “skin bleaches”.</p>
<p>When the US Congress passed the <a href="https://www.fda.gov/about-fda/histories-product-regulation/1938-food-drug-and-cosmetic-act">Food, Drug and Cosmetics Act in 1938</a>, such creams were among the first to be regulated.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317446/original/file-20200226-24659-1ii165p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Part of Twins’s success lay in their recruitment of hawkers to sell their products in townships. Bona, May 1959.</span>
<span class="attribution"><span class="source">Duke University Press</span></span>
</figcaption>
</figure>
<p>After World War II, the negative environmental and health impact of mercury became more apparent. The devastating case of <a href="https://www.sciencedaily.com/releases/2020/02/200213135755.htm">mercury poisoning</a> caused by industrial wastewater in Minamata, Japan, prompted the Food and Drug Administration to take a closer look at mercury’s toxicity, including in cosmetics. Here was a visceral instance of what environmentalist <a href="https://www.rachelcarson.org/">Rachel Carson</a> meant about small, domestic choices making the world uninhabitable.</p>
<p>In 1973, the administration banned all but trace amounts of mercury from cosmetics. Other countries followed suit. South Africa banned mercurial cosmetics in 1975, the European Economic Union in 1976, and Nigeria in 1982. The trade in skin lighteners, nonetheless, continued as other active ingredients – most notably <a href="https://www.rxlist.com/consumer_hydroquinone_melquin_3/drugs-condition.htm">hydroquinone</a> – replaced ammoniated mercury.</p>
<h2>Meanwhile in South Africa</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=767&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=767&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=767&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=964&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=964&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317447/original/file-20200226-24664-1uevavc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=964&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A full-color.
In the early 1960s, colour photography and printing saw skin lightener ads feature a range of light brown and reddish skintones. Drum, September 1961.</span>
<span class="attribution"><span class="source">Duke University Press</span></span>
</figcaption>
</figure>
<p>In apartheid South Africa, the trade was especially robust. Skin lighteners ranked among the most commonly used personal products in black urban households. During the 1980s, activists inspired by <a href="https://www.sahistory.org.za/article/defining-black-consciousness">Black Consciousness</a> and the sentiment “<a href="https://www.theguardian.com/artanddesign/2019/mar/26/kwame-brathwaite-photographer-black-is-beautiful">Black is Beautiful</a>” teamed up with concerned medical professionals to make opposition to skin lighteners part of the <a href="https://www.aluka.org/struggles/collection/AAM">anti-apartheid movement</a>.</p>
<p>In the early 1990s, activists convinced the government <a href="https://theconversation.com/why-its-time-all-african-countries-took-a-stand-on-skin-lightening-creams-49780">to ban</a> all cosmetic skin lighteners containing known depigmenting agents – and to prohibit cosmetic advertisements from making any claims to “bleach”, “lighten” or “whiten” skin. This prohibition was the first of its kind and the regulations immediately shuttered the in-country manufacture of skin lighteners.</p>
<p>South Africa’s regulations testify to the broader antiracist political movement from which they emerged. Thirty years on, however, South Africa again possesses a <a href="https://www.lawforall.co.za/2019/10/skin-lightening-south-africa-law/">robust</a> – if now illicit – trade in skin lighteners. An especially disturbing element is the resurgence of mercurial products.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=905&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=905&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=905&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1137&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1137&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317449/original/file-20200226-24664-9ddcjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1137&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Wits University Press</span></span>
</figcaption>
</figure>
<p>South African researchers have found that over 40% of skin lighteners sold in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-4632.2012.05566.x">Durban</a> and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ced.12720">Cape Town</a> contain mercury.</p>
<p>The activists’ recent victory against Amazon suggests one way forward. They took out a full-page ad in a local newspaper denouncing Amazon’s sale of mercurial skin lighteners as “dangerous, racist, and illegal.” A petition with 23,000 signatures was hand-delivered to the company’s Minnesota office.</p>
<p>By combining antiracist, health, and environmentalist arguments, activists held one of the world’s most powerful companies accountable. They also brought the toxic presence of mercurial skin lighteners to public awareness and made them more difficult to purchase.</p>
<p><em>Lynn M. Thomas’s latest book Beneath the Surface: A Transnational History of Skin Lighteners is available from <a href="https://witspress.co.za/catalogue/beneath-the-surface/">Wits University Press</a> and from <a href="https://www.dukeupress.edu/beneath-the-surface">Duke University Press</a>.</em></p><img src="https://counter.theconversation.com/content/132375/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lynn M. Thomas does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The long history of racist beauty standards alone cannot explain the ongoing global use of harmful skin lighteners.Lynn M. Thomas, History Professor, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1303562020-02-11T12:58:36Z2020-02-11T12:58:36ZBuried in mud: Wildfires threaten North American water supplies<figure><img src="https://images.theconversation.com/files/311236/original/file-20200121-117917-skrq4d.jpg?ixlib=rb-1.1.0&rect=205%2C205%2C3864%2C2522&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Rim Fire burned 256,000 acres of the Stanislaus National Forest and Yosemite National Park in 2013. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/usdagov/9898802086/">(USDA Forest Service, Chris Stewart)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>As rain offers a welcome relief to fire-scorched Australia, <a href="https://theconversation.com/the-sweet-relief-of-rain-after-bushfires-threatens-disaster-for-our-rivers-129449">concerns</a> over flash floods and freshwater contamination cast a shadow on the joy. Already, <a href="https://www.theguardian.com/world/2020/jan/17/hundreds-of-thousands-of-fish-dead-in-nsw-as-bushfire-ash-washed-into-river">massive fish kills</a> have been reported due to heavy ash and sediment in local stream.</p>
<p><a href="https://utilitymagazine.com.au/waternsw-to-protect-dam-water-quality-from-bushfire-risks/">Local reservoirs</a> and <a href="https://theconversation.com/bushfires-threaten-drinking-water-safety-the-consequences-could-last-for-decades-129353">municipal water supplies</a> might become so polluted from the fires that the current water supply infrastructure will be challenged or could no longer treat the water.</p>
<p>Flash floods and water contamination after large-scale wildfires are emerging as real hazards in Australia and many other places, threatening drinking water, ecosystems, infrastructures and recreational activities.</p>
<h2>Water supply from forests is at risk</h2>
<p>In many ways, this is not surprising. Forests <a href="https://doi.org/10.1073/pnas.1605354113">provide water</a> to 90 per cent of the world’s most populous cities, and most of these forests already yield degraded water quality. Forests also provide other <a href="https://blog.globalforestwatch.org/data-and-research/watersheds-lost-up-to-22-of-their-forests-in-14-years-heres-how-it-affects-your-water-supply">essential water services</a> like flood control, hydroelectricity, fishing and recreational opportunities.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/with-costs-approaching-100-billion-the-fires-are-australias-costliest-natural-disaster-129433">With costs approaching $100 billion, the fires are Australia's costliest natural disaster</a>
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</p>
<hr>
<p>Our <a href="https://doi.org/10.1016/j.scitotenv.2017.08.112">recent global analyses</a> clearly showed Australia’s water supply was at high risk from wildfires. We also found areas on every continent except Antarctica face similar risks. In North America, <a href="https://www.cbc.ca/radio/we-have-to-learn-to-live-with-fire-how-wildfires-are-changing-canadian-summers-1.5135539">larger and more severe fires</a> have created new challenges for forest and water managers.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311720/original/file-20200124-162185-dvbmms.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The 2015 Stouts Creek Fire in Oregon led to more runoff and erosion.</span>
<span class="attribution"><span class="source">(Kevin Bladon)</span></span>
</figcaption>
</figure>
<h2>Post-fire water hazards</h2>
<p>Wildfires can have many detrimental impacts on water supplies. The effects can last for <a href="https://www.sciencedaily.com/releases/2020/01/200110093836.htm">multiple decades</a> and include drinking water pollution, reservoir sedimentation, flash floods and reduced recreational benefits from rivers.</p>
<p>These impacts represent a growing hazard as populations expand, and communities encroach onto forest landscapes.</p>
<p>Looking closer, wildfires <a href="https://doi.org/10.1038/s41467-018-03735-6">change the amount of water that comes from</a> upstream forests and the seasonal timing of water flows. Such changes complicate water resource allocation as less water might be available during periods of high demand.</p>
<p>When rainstorms follow large and severe wildfires, they tend to flush ash, nutrients, <a href="https://cen.acs.org/environment/water/Benzene-found-water-supply-fire/97/web/2019/04">heavy metals and toxins</a>, and sediments into streams and rivers. This contamination from wildfires causes problems for the health of downstream rivers and lakes, as well as safe drinking water production.</p>
<p>Mercury, which can be deposited on leaves and absorbed by plants, is a particular concern. During a fire, <a href="https://doi.org/10.5194/acp-18-7263-2018">mercury may be re-emitted in large amounts and deposited</a> in nearby lakes, wetlands and other water, where <a href="https://doi.org/10.1073/pnas.0609798104">it accumulates</a> in the food web, and into fish, that are caught and eaten by people. Indigenous communities living in fire-prone forests in Canada and who already struggle with mercury contamination might be particularly exposed.</p>
<h2>Risks in North America</h2>
<p>Polluted water creates many expensive, difficult and long-lasting challenges for the drinking water treatment process. For example, water remained difficult to treat for <a href="https://denverwatertap.org/2017/06/16/legacy-colorados-largest-wildfire/">15 years after</a> after the 2002 Hayman fire in Colorado. </p>
<p>The quality of the post-fire water increased the chances of forming undesirable byproducts of <a href="https://doi.org/10.2134/jeq2019.04.0172">water disinfection</a>. These toxic chemicals had to be removed before the water could be supplied to more than half a million users in Denver.</p>
<p>But most of the fire-prone areas in North America lack large-scale vulnerability assessments of their municipal water supplies — and not because the risks are inconsequential.</p>
<p>In Canada and the United States, one large and severe wildfire might increase drinking water production costs by US$10 million to US$100 million. In southern California, <a href="https://www.cbsnews.com/pictures/deadly-california-mudslides/">mudslides from heavy rainfall</a> after wildfires caused 23 deaths and produced more than US$100 million of structural damage in 2018.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311722/original/file-20200124-162190-1p38eew.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Boulders moved in the 2018 Montecito mudslide.</span>
<span class="attribution"><span class="source">(WERF, 2018)</span></span>
</figcaption>
</figure>
<p>The financial burden of these changes is eventually carried by taxpayers. Adopting nature-friendly solutions to reduce severe wildfires in upstream forests, such as <a href="https://e360.yale.edu/features/why-restoring-watersheds-is-a-new-priority-in-a-warming-world">prescribed burns</a> under controlled conditions, will lower the bill and provide better protection of water services.</p>
<h2>Protecting the source</h2>
<p>Forest health is <a href="https://doi.org/10.1126/science.aaa9092">already declining across Canada</a> and the <a href="https://doi.org/10.1016/j.envpol.2008.03.003">United States</a>. This trend will likely continue because of <a href="https://doi.org/10.1126/science.aac6759">climate change and land degradation</a> linked to human activities.</p>
<p>Climate projections suggest that fires will happen <a href="http://www.publish.csiro.au/wf/WF09002">more frequently</a> and become <a href="https://doi.org/10.1088/1748-9326/aa7e6e">more severe</a>. <a href="https://doi.org/10.1073/pnas.1617394114">Urban sprawl</a> also increases the likelihood of these fires happening in the vicinity of homes.</p>
<p>Combined with increased rainfall and declining snowfall, this makes river flows and the quality of surface water less predictable. Consequently, water supplies become <a href="https://globalnews.ca/news/6190102/fresh-water-canada-climate-change/">less reliable</a>.</p>
<p>In light of these environmental changes and the inevitability of wildfires, countries like Canada and the United States can expect <a href="https://doi.org/10.1038/d41586-018-06783-6">cascading hazards</a> with impacts similar in magnitude to what is now happening in Australia.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/5kvjkpig3T4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Therefore, governments need to seize <a href="https://doi.org/10.1016/j.jhydrol.2019.124360">existing opportunities</a>, such as leveraging existing data and taking advantage of growing computing power, to measure <a href="https://doi.org/10.1029/2018EF000867">wildfire risk to water supplies</a>. A tailored wildfire-water risk reduction strategy can help achieve better source water protection, improve infrastructure and foster preventive disaster planning.</p>
<p>There is no doubt we will learn more as our knowledge of <a href="https://www.theguardian.com/us-news/2019/nov/21/wildfire-prescribed-burns-california-native-americans">Indigenous forest management practices</a> <a href="https://theconversation.com/native-people-did-not-use-fire-to-shape-new-englands-landscape-129429">improves</a>. Instead of reinventing the wheel we must try to keep water in the landscape by <a href="https://theconversation.com/how-to-fight-wildfires-and-climate-change-with-wetlands-117356">restoring wetlands</a>, and accept a <a href="https://doi.org/10.1029/2019EO137917">helping hand</a> when offered.</p>
<p>Because ultimately, forests and clean water resources are of paramount importance to our own future.</p><img src="https://counter.theconversation.com/content/130356/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>François-Nicolas Robinne receives funding from Global Water Futures and the Canadian Partnership for Wildland Fire Science (Canada Wildfire). </span></em></p><p class="fine-print"><em><span>Dennis Hallema receives funding from the USDA Forest Service and U.S. Fish and Wildlife Service.</span></em></p><p class="fine-print"><em><span>Kevin Bladon receives funding from the U.S. National Science Foundation and the U.S. Forest Service. </span></em></p>Wildfires reduce the reliability of city water supplies in North America. But active forest management provides a key to the solution.François-Nicolas Robinne, Postdoctoral fellow in Environmental Geography, University of AlbertaDennis W Hallema, Research Assistant Professor, North Carolina State UniversityKevin D. Bladon, Assistant Professor, Oregon State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1297882020-01-29T19:07:56Z2020-01-29T19:07:56ZPlants safely store toxic mercury. Bushfires and climate change bring it back into our environment<figure><img src="https://images.theconversation.com/files/309828/original/file-20200114-103971-187s8fv.jpg?ixlib=rb-1.1.0&rect=0%2C197%2C5874%2C3763&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Industrial activities like mining, fossil fuel combustion, and cement production release mercury into the environment.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Climate change and bushfire may exacerbate recent mercury pollution and increase exposure to the poisonous neurotoxin, according to our study published in the <a href="https://link.springer.com/article/10.1007%2Fs10933-020-00111-7">Journal of Paleolimnology</a>.</p>
<p>Mercury stored in plants is released during bushfires, suggesting Australia is particularly at risk. </p>
<p>Our study in the Venezuelan Andes examined how mercury deposits responded when the world warmed by about 3°C between 14,500 and 11,500 years ago. (Scientists call this period the transition from the Last Glacial Maximum to the Holocene).</p>
<p>We found the amount of mercury deposited in the environment at this time increased four-fold. </p>
<h2>A dangerous neurotoxin</h2>
<p>Mercury is a naturally occurring but dangerous <a href="https://www.medicalnewstoday.com/articles/320563.php#symptoms">neurotoxin</a> that, in sufficient amounts, can cause impaired motor skills, breathing difficulty and memory problems in humans. </p>
<p>Once in the environment, mercury builds up in the bodies of animals. The build-up is magnified when those animals are then eaten by other animals, and so on. This process is called <a href="http://www.novapublishers.org/catalog/product_info.php?products_id=41858">bioaccumulation and biomagnification</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-emits-mercury-at-double-the-global-average-82577">Australia emits mercury at double the global average</a>
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</em>
</p>
<hr>
<p>Industrial activities such as mining, fossil fuel combustion and cement production release mercury into the environment. </p>
<p>Over the past 150 years, <a href="https://www.ncbi.nlm.nih.gov/pubmed/29897241">humans have tripled the amount of mercury in the atmosphere</a>. It can remain there for months, and be transported by wind to even the most remote ecosystems on Earth. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309858/original/file-20200114-103987-1u7d48b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Mercury is dangerous to humans and wildlife.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Climate change unlocks mercury deposits</h2>
<p>Average global temperatures have <a href="https://earthobservatory.nasa.gov/world-of-change/DecadalTemp">increased by 0.8°C since 1880</a> , with <a href="https://earthobservatory.nasa.gov/world-of-change/DecadalTemp">two-thirds of this warming occurring since 1975</a>. Understanding how mercury responded to past known climate change may help us forecast future mercury exposure as the climate warms. </p>
<p>The Last Glacial Maximum (also known as an ice age), and the start of the Holocene (the present period), occurred between 19,000 and 11,700 years ago. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/another-problem-with-chinas-coal-mercury-in-rice-92974">Another problem with China's coal: Mercury in rice</a>
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</em>
</p>
<hr>
<p>It was not a smooth transition; global climate oscillated between warm and cold at this time. </p>
<p>Abrupt returns to cold, glacial-like conditions occurred during two periods of time called the <a href="https://theconversation.com/new-evidence-that-an-extraterrestrial-collision-12-800-years-ago-triggered-an-abrupt-climate-change-for-earth-118244">Older Dryas and the Younger Dryas</a>. These climate oscillations provide a unique opportunity to understand how mercury in our environment responds to rapid climate change. </p>
<h2>Looking in lakes</h2>
<p>Layers of sediment settle to the bottom of lakes over thousands of years. By collecting sediment cores, scientists can <a href="https://www.mercury-australia.com.au/monitoring-mercury-in-sediments/">precisely date each layer and reconstruct past climates</a>. Lake sediment also provide a good historical of mercury contamination.</p>
<p>We examined how mercury deposits in a small lake – the Laguna de Los Anteojos in the Venezuelan Andes – changed as the ecosystem shifted with the climate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309857/original/file-20200114-103994-e46rc2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">We studied how mercury deposits in this small lake, named Laguna de Los Anteojos, changed as the climate warmed.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Laguna_los_Anteojos.JPG">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>We found the amount of mercury in the lake increased rapidly as temperature increased – which doesn’t bode well for us. </p>
<p>It suggests human-caused global warming might drive a similar increase in the amount of mercury deposited in remote ecosystems, even if emissions are reduced.</p>
<p>As the climate warmed, we found, more mercury entered water systems. Once in the aquatic system, it can be absorbed by plants or consumed by animals, and pass on up the food chain in ever-increasing amounts.</p>
<h2>Bushfires dump more mercury into the environment</h2>
<p>Plants can store a significant pool of mercury from the atmosphere, which is good - until fires occur. </p>
<p>Unfortunately, mercury stored by vegetation is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1797869/">released during burning</a>. This is particularly the case in contaminated areas, where plants store significant quantities of mercury emitted from human activities <a href="https://theconversation.com/mercury-pollution-from-decades-past-may-have-been-re-released-by-tasmanias-bushfires-114603">such as mining</a>. </p>
<p>Given the recent catastrophic fires engulfing large tracts of land in Australia, that’s a worry. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309856/original/file-20200114-103966-1177p5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plants can store a significant pool of mercury from the atmosphere, which is good - until bushfires occur.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>There’s a dearth of mercury studies in Australia (a fact <a href="https://www.unenvironment.org/resources/publication/global-mercury-assessment-2018">acknowledged even by the United Nations</a>) so it’s not yet possible to estimate mercury emissions from the recent Australian bushfires. </p>
<p>One thing we do know, however, is the number of bushfires in Australia is not expected to decrease.</p>
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Read more:
<a href="https://theconversation.com/many-of-our-plants-and-animals-have-adapted-to-fires-but-now-the-fires-are-changing-129754">Many of our plants and animals have adapted to fires, but now the fires are changing</a>
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</em>
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<p>It sounds bleak, but <a href="https://www.mercury-australia.com.au/">Australian researchers</a> are working hard to better understand how mercury behaves as our ecosystem changes. </p>
<p>The more we know, the better our chances of mitigating mercury pollution and the risk it poses to humans and wildlife.</p><img src="https://counter.theconversation.com/content/129788/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Larissa Schneider receives funding from The Australian Research Council and from The Brazilian National Council for Scientific and Technological Development. She is affiliated with The Australian National University and The Australian Research Council Centre of Excellence for Biodiversity and Heritage.</span></em></p><p class="fine-print"><em><span>Nathan D Stansell receives funding from the U.S. National Science Foundation. </span></em></p><p class="fine-print"><em><span>Simon Haberle receives funding from the ARC.</span></em></p><p class="fine-print"><em><span>Colin Cooke does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Plants can store mercury and keep it from contaminating waterways, air and soils. Unfortunately, that mercury is released when plants burn.Larissa Schneider, DECRA fellow, Australian National UniversityColin Cooke, University of AlbertaNathan D Stansell, Associate Professor, Northern Illinois UniversitySimon Haberle, Professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.