tag:theconversation.com,2011:/fr/topics/arsenic-4415/articles
Arsenic – The Conversation
2023-09-14T12:30:25Z
tag:theconversation.com,2011:article/211657
2023-09-14T12:30:25Z
2023-09-14T12:30:25Z
The importance of shining a light on hidden toxic histories
<figure><img src="https://images.theconversation.com/files/548169/original/file-20230913-23-64mqmc.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C2927%2C1970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Activists in Newark, N.J., offer tours that teach visitors about the city's legacy of industrial pollution and environmental racism.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-aerial-view-of-newark-new-jersey-shows-smoke-news-photo/635229321?adppopup=true">Charles Rotkin/Corbis via Getty Images</a></span></figcaption></figure><p>Indianapolis proudly claims <a href="https://www.wthr.com/article/entertainment/hoosiers-remember-elvis-presley-indianapolis-concert-amid-new-movie-buzz/531-503bd6a9-c645-4704-bfad-7577126aaad6">Elvis’ last concert</a>, <a href="https://www.youtube.com/watch?v=A2kWIa8wSC0">Robert Kennedy’s speech</a> in response to Martin Luther King Jr.’s assassination, and the Indianapolis 500. There’s a 9/11 memorial, a <a href="https://www.indianawarmemorials.org/explore/medal-of-honor-memorial/">Medal of Honor Memorial</a> and a statue of former NFL quarterback Peyton Manning.</p>
<p>What few locals know, let alone tourists, is that the city also houses one of the largest dry cleaning <a href="https://www.epa.gov/superfund/what-superfund">Superfund sites</a> in the U.S.</p>
<p>From 1952 to 2008, Tuchman Cleaners laundered clothes <a href="https://www.doi.org/10.3389/fpubh.2021.638082">using perchloroethylene</a>, or PERC, a neurotoxin and possible carcinogen. Tuchman operated a chain of cleaners throughout the city, which sent clothes to a facility on Keystone Avenue for cleaning. It was also the location where used solution was stored in underground tanks.</p>
<p>Inspectors noted the presence of volatile organic compounds from leaking tanks and possible spills as early as 1989. By 1994, an underground plume had spread to a nearby aquifer. By the time the EPA became involved in 2011, the <a href="https://response.epa.gov/site/site_profile.aspx?site_id=7130">underground chemical plume</a> had seeped more than a mile underneath a residential area, reaching a well that supplies drinking water to the city.</p>
<p>When geographer <a href="https://liberalarts.iupui.edu/departments/geography/directory/owen-dwyer/">Owen Dwyer</a>, earth scientist <a href="https://science.iupui.edu/people-directory/people/filippelli-gabriel.html">Gabe Filippelli</a> and I investigated and wrote about the social and environmental <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-24/dirty-laundry-toxic-heritage-dry-cleaning-indianapolis-indiana-elizabeth-kryder-reid-owen-dwyer-gabriel-filippelli?context=ubx&refId=242e9f98-2f2d-4587-9449-99734e77a875">history of dry cleaning in Indianapolis</a>, we were struck by how few people outside of the dry cleaning and environmental management fields were aware of this environmental damage. </p>
<p>There are no markers or memorials. There is no mention of it – or any other accounts of contamination – in Indianapolis’ many museums. This kind of silence has been called “<a href="https://www.orionmagazine.org/article/environmental-amnesia/">environmental amnesia</a>” or “<a href="https://www.jstor.org/stable/24906248">collective forgetting</a>.”</p>
<p>Societies celebrate heroes and commemorate tragedies. But where in public memory is environmental harm? What if people thought about it not only as a science or policy problem, but also as a part of history? Would it make a difference if pollution, along with biodiversity loss and climate change, was seen as part of our shared heritage? </p>
<h2>The slow violence of contamination</h2>
<p>Environmental harm often takes place gradually and out of sight, and this could be one reason why there’s so little public conversation and commemoration. In 2011, Princeton English professor <a href="https://www.hup.harvard.edu/catalog.php?isbn=9780674072343">Rob Nixon</a> came up with a term for this kind of environmental degradation: slow violence. </p>
<p>As underground storage tanks leak, <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-10/ghost-wrecks-anthropocene-enduring-toxic-legacy-pacific-war-matthew-carter-ashley-meredith-augustine-kohler-ranger-walter-bill-jeffrey-paul-heersink?context=ubx&refId=9df11100-ce32-4e00-b590-5b9769b00df2">shipwrecks corrode</a>, coal ash ponds seep and <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-6/toxic-heritage-forever-confronting-pfas-contamination-toxicity-lived-experience-thomas-pearson-daniel-renfrew?context=ubx&refId=ef6c0e6a-b9da-4008-9689-9a43a2dc3055">forever chemicals spread</a>, the creeping pace of poisoned soil and water fails to garner the attention that more dramatic environmental disasters attract.</p>
<p>Certain interests benefit from hiding the costs of pollution and its remediation. Sociologists <a href="https://www.russellsage.org/publications/sites-unseen">Scott Frickel and James R. Elliott</a> have studied urban pollution, and they highlight three reasons for its pervasiveness and persistence. </p>
<p>First, in cities, small factories, auto repair shops, dry cleaners and other light industries sometimes only stay open for a decade or two, making it challenging to regulate them and track their environmental impacts over time. By the time contamination is discovered, many facilities have long been shuttered or purchased by new owners. And the polluters have a direct financial interest in not being connected with it, since they could be held liable and forced to pay for cleanup.</p>
<p>Similarly, urban neighborhoods tend to have shifting demographics, and local residents are often not aware of historical pollution. </p>
<p>Finally, it can simply be politically expedient to look the other way and ignore the consequences of pollution. Cities may be concerned that publicizing toxic histories discourage investment and depress property values, and politicians are hesitant to fund projects that may have a long-term benefit but short-term costs. Indianapolis, for example, tried for decades to avoid mitigating the raw sewage flowing into the White River and Fall Creek, arguing it was too expensive to deal with. Only when required by a <a href="https://www.epa.gov/sites/default/files/2013-09/documents/indy0610-cd.pdf">consent decree</a> did the city start to address the problem.</p>
<p>Toxic legacies are also difficult to track because their effects may be hidden by distance and time. Anthropologist Peter Little <a href="https://global.oup.com/academic/product/burning-matters-9780190934552?cc=us&lang=en&">traced the outsourcing of electronics waste recycling</a>, which is shipped from the places where electronics are bought and used, to countries such as Ghana, where labor is cheap and environmental regulations lax. </p>
<p>Then there are the toxic traces of military conflicts, which linger long after the fighting has stopped and troops have returned home. Historian and geologist Daniel Hubé has documented <a href="https://doi.org/10.1080/19475020.2017.1393347">the long-term environmental impact of World War I munitions</a>. </p>
<p>At the end of the war, unused and unexploded bombs and chemical weapons had to be disposed of. In France, at a site known as <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-25/cleaning-battlefields-times-war-polluted-soils-times-peace-case-study-silent-visible-toxic-legacy-great-war-daniel-hub%C3%A9-tobias-bausinger?context=ubx&refId=630129c7-e447-48fd-a959-24bf0bae1d83">Place à Gaz</a>, hundreds of thousands of chemical weapons were burned. Today, the soils have been found to have extraordinarily high levels of arsenic and other heavy metals. </p>
<p>More than a century after the end of the war, little grows on the contaminated, barren land.</p>
<h2>Toxic tours and teaching moments</h2>
<p>There’s a growing movement to make toxic histories more visible.</p>
<p>In Providence, Rhode Island, artist Holly Ewald founded the <a href="http://www.upparts.org/">Urban Pond Procession</a> to call attention to Mashapaug Pond, which was contaminated by <a href="https://medallicartcollector.com/gorham.shtml">a Gorham Silver factory</a>. She worked with community partners to create wearable sculptures, puppets and giant fish, all of which were carried and worn in an annual parade that took place from 2008 to 2017.</p>
<figure class="align-center ">
<img alt="People march along a sidewalk playing instruments and holding signs featuring fish." src="https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548175/original/file-20230913-3869-qv2hbs.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Urban Pond Procession took place each summer for 10 years in Providence, R.I.</span>
<span class="attribution"><span class="source">Photo by Mary Beth Meehan, UPP Collection, Providence Public Library</span></span>
</figcaption>
</figure>
<p>Cultural anthropologist Amelia Fiske collaborated with artist Jonas Fischer to create the graphic novel “<a href="https://utorontopress.com/9781487509538/toxic/">Tóxico</a>,” which will be published in 2024. It depicts petroleum pollution in the Ecuadorian Amazon, as well as the struggles of those fighting for environmental justice. </p>
<p>Toxic tours can educate the public about the histories, causes and consequences of environmental harm. For example, <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-31/environmental-justice-tours-transformative-narratives-struggle-solidarity-activism-ana-isabel-baptista?context=ubx&refId=7e43d2ce-0c5c-41a4-a9b6-40ce10c0848c">Ironbound Community Corporation</a> in Newark, New Jersey, offers a tour of severely contaminated sites, such as the location of the former <a href="https://www.nytimes.com/1998/11/08/nyregion/newark-s-toxic-tomb-six-acres-fouled-dioxin-agent-orange-s-deadly-byproduct.html">Agent Orange factory</a>, where the sediment in the sludge is laced with the carcinogen dioxin. The tour also goes by a detention center <a href="https://www.epa.gov/brownfields/overview-epas-brownfields-program">that’s built on a brownfield</a>, which has only undergone industrial-level remediation because that’s the standard all prisons are held to.</p>
<p>In 2017, the <a href="https://www.humanitiesactionlab.org/">Humanities Action Lab</a> organized “<a href="https://climatesofinequality.org/">Climates of Inequality</a>,” a traveling exhibit co-curated by more than 20 universities and local partners exploring environmental issues affecting communities around the world. The <a href="https://www.taylorfrancis.com/chapters/oa-edit/10.4324/9781003365259-34/toxic-heritage-reparations-activating-memory-environmental-climate-justice-liz-%C5%A1ev%C4%8Denko?context=ubx&refId=e2e664c7-b4d9-4497-b4a4-6d4f5dd1b009">exhibit</a> brings attention to polluted waterways, the impacts of climate change, ecological damage on Indigenous lands and the ways in which immigrant agricultural workers experience heat stress and chronic pesticide exposure. The exhibits also explore the affected communities’ resilience and advocacy.</p>
<p>These stories of pollution and contamination, and their effects on people’s health and livelihoods, represent only a sampling of current efforts to curate toxic heritage. As sociologist Alice Mah writes in her foreword to “<a href="https://www.routledge.com/Toxic-Heritage-Legacies-Futures-and-Environmental-Injustice/Kryder-Reid-May/p/book/9781032429977">Toxic Heritage</a>”: “Reckoning with toxic heritage is an urgent collective task. It is also unsettling work. It requires confronting painful truths about the roots of toxic injustice with courage, honesty, and humility.”</p>
<p>I see public commemoration of hidden toxic histories as a way to push back against denial, habituation and amnesia. It creates a space for public conversation, and it opens up possibilities for a more just and sustainable future.</p><img src="https://counter.theconversation.com/content/211657/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elizabeth Kryder-Reid receives funding from Indiana University and the Fulbright Program.</span></em></p>
Societies celebrate heroes and commemorate tragedies. But why is there so little public acknowledgment of environmental disasters?
Elizabeth Kryder-Reid, Chancellor's Professor of Anthropology and Museum Studies, Indiana University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/200689
2023-06-05T12:09:06Z
2023-06-05T12:09:06Z
Arsenic contamination of food and water is a global public health concern – researchers are studying how it causes cancer
<figure><img src="https://images.theconversation.com/files/529435/original/file-20230531-23-iq2312.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C937%2C768&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One symptom of arsenic poisoning is the growth of plaques on the skin called arsenical keratosis.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/tQzvii">Anita Ghosh/REACH via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Arsenic is a naturally occurring element found in the Earth’s crust. Exposure to arsenic, often through contaminated food and water, is associated with various negative health effects, <a href="https://www.ncbi.nlm.nih.gov/books/NBK304375/">including cancer</a>. </p>
<p>Arsenic exposure is a global public health issue. A 2020 study estimated that <a href="https://doi.org/10.1126/science.aba1510">up to 200 million people wordwide</a> are exposed to arsenic-contaminated drinking water at levels above the legal limit of <a href="https://www.atsdr.cdc.gov/csem/arsenic/standards.html">10 parts per billion</a> set by the U.S. Environmental Protection Agency and World Health Organization. <a href="https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Some-Drinking-Water-Disinfectants-And-Contaminants-Including-Arsenic-2004">More than 70 countries</a> are affected, including the United States, Spain, Mexico, Japan, India, China, Canada, Chile, Bangladesh, Bolivia and Argentina.</p>
<p>Since many countries are still affected by high levels of arsenic, we believe arsenic exposure is a global public health issue that requires urgent action. <a href="https://stempel.fiu.edu/research/labs/cancer-research/">We study</a> how <a href="https://www.researchgate.net/profile/Cristina-Andrade-Feraud">exposure to toxic metals</a> like arsenic can <a href="https://scholar.google.com/citations?user=v42J5dMAAAAJ&hl=en">lead to cancer</a> through the formation of <a href="https://theconversation.com/triggering-cancer-cells-to-become-normal-cells-how-stem-cell-therapies-can-provide-new-ways-to-stop-tumors-from-spreading-or-growing-back-191559">cancer stem cells</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ftvJr-BycJY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Arsenic water contamination predominantly affects communities of color in the U.S.</span></figcaption>
</figure>
<h2>Arsenic contamination of food and water</h2>
<p>Your body can absorb arsenic <a href="https://www.atsdr.cdc.gov/csem/arsenic/what_routes.html">through several routes</a>, such as inhalation and skin contact. However, the most common source of arsenic exposure is through contaminated drinking water or food.</p>
<p>People who live in areas with <a href="https://www.who.int/news-room/fact-sheets/detail/arsenic">naturally high levels of arsenic in the soil and water</a> are at particular risk. In the U.S., for example, that includes regions in the Southwest such as Arizona, Nevada and New Mexico. Additionally, <a href="https://www.wolterskluwer.com/en/solutions/ovid/environmental-and-occupational-medicine-3485">human activities</a> such as mining and agriculture can also increase arsenic in food and water sources.</p>
<p>High levels of arsenic can also be found in <a href="https://theconversation.com/should-we-worry-about-arsenic-in-baby-cereal-and-drinking-water-57948">food and drink products</a>, <a href="https://doi.org/10.1016/j.fct.2018.01.018">particularly rice</a> and rice-based products like rice cereals and crackers. A 2019 Consumer Reports investigation even found that <a href="https://www.consumerreports.org/water-quality/arsenic-in-some-bottled-water-brands-at-unsafe-levels-a1198655241/">some brands of bottled water</a> sold in the U.S. contained levels of arsenic that exceeded the legal limit. Alarmingly, multiple studies have also found that several <a href="https://www.consumerreports.org/food-safety/most-baby-foods-contain-arsenic-lead-and-other-heavy-metals/">popular baby food brands</a> contained arsenic at concentrations much higher than the legal limit.</p>
<h2>Arsenic and cancer stem cells</h2>
<p>Chronic exposure to arsenic increases the <a href="https://doi.org/10.1093/jnci/djx201">risk</a> <a href="https://doi.org/10.1016/j.scitotenv.2019.136071">of</a> <a href="https://doi.org/10.1016/j.scitotenv.2019.134128">developing</a> <a href="https://doi.org/10.1158/1055-9965.epi-13-0234-t">multiple</a> <a href="https://doi.org/10.1016/j.scitotenv.2015.08.070">types</a> <a href="https://doi.org/10.1016/s0041-008x(02)00022-4">of cancer</a>.</p>
<p>The mechanisms by which arsenic causes cancer are complex and not yet fully understood. However, research suggests that <a href="https://doi.org/10.3109%2F10408444.2010.506641">arsenic can</a> <a href="https://doi.org/10.1021%2Facs.chemrestox.9b00464">damage DNA</a>, <a href="https://doi.org/10.1007/s00204-013-1131-4">disrupt cell</a> <a href="https://doi.org/10.1093/toxsci/kfy247">signaling pathways</a> and <a href="https://doi.org/10.1186/1476-069X-12-73">impair the</a> <a href="https://doi.org/10.1016/j.cotox.2018.01.003">immune system</a>, all of which can contribute to cancer development.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy images of ovarian epithelial cells before and after chronic arsenic exposure" src="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=235&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=235&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=235&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=295&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=295&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=295&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 image on the left shows ovarian epithelial cells under normal conditions. The image on the right shows the cells after three weeks of chronic arsenic exposure at 75 parts per billion.</span>
<span class="attribution"><span class="source">Cristina M. Andrade-Feraud/Azzam Laboratory at FIU</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Scientists <a href="https://doi.org/10.1289%2Fehp.1204987">have also linked</a> <a href="https://doi.org/10.1289%2Fehp.0901059">chronic arsenic exposure</a> to the development of <a href="https://theconversation.com/triggering-cancer-cells-to-become-normal-cells-how-stem-cell-therapies-can-provide-new-ways-to-stop-tumors-from-spreading-or-growing-back-191559">cancer stem cells</a>. These are cells within tumors thought to be responsible for cancer growth and spread. Like normal stem cells in the body, cancer stem cells can develop into many different types of cells. At what stage of cellular development a stem cell acquires the genetic mutation that turns it into a cancer stem cell remains unknown.</p>
<p><a href="https://stempel.fiu.edu/research/labs/cancer-research/">Our research</a> aims to identify what type of cell arsenic targets to form a cancer stem cell. We are currently using cell cultures obtained from the same organ at different stages of cellular development to examine how the origins of cells affect the formation of cancer stem cells.</p>
<p>Preventing chronic arsenic exposure is critical to reducing the burden of arsenic-related health effects. Further research is needed to understand arsenic-induced cancer stem cell formation and develop effective strategies to prevent it. In the meantime, continued monitoring and regulation of this toxic metal in food and water sources could help improve the health of affected communities.</p><img src="https://counter.theconversation.com/content/200689/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Diana Azzam receives funding from the Florida Department of Health and the National Institute of Health.</span></em></p><p class="fine-print"><em><span>Cristina Andrade-Feraud 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>
Millions of people worldwide are exposed via soil and water to arsenic, whether naturally occurring or related to pollution. Chronic exposure is linked to the formation of cancer stem cells.
Cristina Andrade-Feraud, Ph.D. Candidate in Environmental Health Sciences, Florida International University
Diana Azzam, Assistant Professor of Environmental Health Sciences, Florida International University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/199865
2023-03-01T01:57:13Z
2023-03-01T01:57:13Z
Despite restrictions elsewhere, NZ still uses a wood preservative linked to arsenic pollution
<figure><img src="https://images.theconversation.com/files/512527/original/file-20230227-2266-t2s8nz.jpg?ixlib=rb-1.1.0&rect=8%2C152%2C5982%2C3736&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/speedshutter Photography</span></span></figcaption></figure><p>Timber with a green-grey hue – treated with copper chromium arsenic (CCA) – is a common sight in New Zealand. But how many people are aware that it <a href="https://www.cellulosechemtechnol.ro/pdf/CCT7-8(2022)/p.705-716.pdf">pollutes the environment</a>, is associated with health risks and is a toxic waste complicating the transition to a circular bioeconomy?</p>
<p>Other countries, including <a href="https://www.betterhealth.vic.gov.au/health/healthyliving/copper-chrome-arsenic-cca-treated-timber">Australia</a>, the <a href="https://www.cpsc.gov/s3fs-public/270_0.pdf">US</a> and the EU, have stopped or restricted the use of CCA, moved to safer alternatives and established viable end-of-life disposal options. </p>
<p>The ingredients of CCA are the heavy metals copper, chromium and arsenic. They don’t decompose and can’t be destroyed like organic compounds by incineration. </p>
<p>The heavy metals <a href="https://www.sciencedirect.com/science/article/pii/S0301479705000113">leach from the timber</a>, polluting soil and water. When CCA-treated timber is burned, most arsenic becomes volatile and pollutes the air, while chromium and copper contaminate the ash. </p>
<p>The World Health Organization (WHO) lists arsenic among the top ten chemicals of <a href="https://www.who.int/news-room/fact-sheets/detail/arsenic">major public health concern</a>. It is a confirmed carcinogen. Chromium and copper are not without health risks either. </p>
<h2>Banned or restricted elsewhere</h2>
<p>In the early 2000s, the US Environmental Protection Agency and the timber industry agreed to <a href="http://npic.orst.edu/ingred/ptype/treatwood/ccareg.html">restrict CCA-treated timber to industrial uses</a>. This was driven by concerns about human exposure to arsenic from playground equipment, decks, picnic tables and other uses. </p>
<p>Most other developed countries followed with similar restrictions. CCA is <a href="https://echa.europa.eu/information-on-chemicals/biocidal-active-substances">no longer registered</a> as a wood preservative in the EU.</p>
<p>But New Zealand’s treated-timber market is still dominated by CCA. It is used abundantly in playgrounds and residential buildings with a high risk of human exposure. This is despite Standards New Zealand having approved <a href="https://www.standards.govt.nz/shop/nzs-36402003/">more benign alternatives</a>. </p>
<figure class="align-center ">
<img alt="A playground using mostly timber" src="https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512754/original/file-20230228-2171-oa9ziy.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">New Zealand continues to use CCA-treated timber in playgrounds and residential buildings.</span>
<span class="attribution"><span class="source">Shutterstock/kelifamily</span></span>
</figcaption>
</figure>
<p>New Zealand’s Environmental Protection Authority also <a href="https://www.epa.govt.nz/assets/Uploads/Documents/Hazardous-Substances/Guidance/Report-on-CCA-safety-by-Deborah-Read-April-2003.pdf">recommends</a> building playgrounds from alternative materials, providing consumer information at point of sale and greater dissemination of precautionary health advice. But these recommendations have been ignored in New Zealand for two decades. </p>
<p>Stakeholders have not adopted the <a href="https://www.standards.org.au/standards-catalogue/sa-snz/building/tm-012/as--5605-2007">standard</a> developed jointly by Standards Australia and Standards New Zealand. The standard contains a consumer safety information sheet, which states CCA-treated timber cannot be used for products in direct contact with foodstuffs, garden furniture, exterior seating, children’s play equipment, patio and domestic decking and handrails. </p>
<p>It also details appropriate disposal and outlines precautions during handling: </p>
<ul>
<li><p>avoid sawing</p></li>
<li><p>wear dust masks, gloves and eye protection</p></li>
<li><p>wash hands and face after working with CCA-treated timber. </p></li>
</ul>
<h2>Environmental and health risks</h2>
<p>New Zealand <a href="https://www.epa.govt.nz/assets/Uploads/Documents/Hazardous-Substances/Guidance/Report-on-CCA-safety-by-Deborah-Read-April-2003.pdf">excluded environmental risks</a> from its CCA safety assessment. Yet environmental risks were leading reasons to phase out CCA overseas. </p>
<p>There are several domestic examples of environmental pollution by CCA.</p>
<p><a href="https://www.gns.cri.nz/news/high-arsenic-levels-in-urban-air-a-health-hazard-study-shows/">Arsenic concentration</a> in the air during winter <a href="https://environment.govt.nz/assets/Publications/Files/ambient-guide-may02.pdf">exceeds New Zealand’s ambient air-quality guidelines</a>. This is caused by inappropriate burning of CCA-treated timber in log fires and burn-offs by the agricultural sector.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/like-having-a-truck-idling-in-your-living-room-the-toxic-cost-of-wood-fired-heaters-140737">'Like having a truck idling in your living room': the toxic cost of wood-fired heaters</a>
</strong>
</em>
</p>
<hr>
<p>Arsenic concentration was <a href="https://doi.org/10.5194/hessd-3-2037-2006">predicted to exceed the drinking water standard</a> in slow-flowing Marlborough aquifers.</p>
<p>While soil contamination is localised around CCA-treated timber, these hotspots can be frequent. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969705005231">Vineyards</a>, for example, feature 500-600 posts per hectare. Land-use change for urban development will require <a href="https://www.waikatoregion.govt.nz/assets/WRC/WRC-2019/TR201811.pdf">significant remediation</a>. </p>
<figure class="align-center ">
<img alt="Vineyward during winter, with lots of timber posts." src="https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=487&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=487&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512538/original/file-20230227-691-4nkxff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=487&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Timber treated with CCA is used in vineyards.</span>
<span class="attribution"><span class="source">Shutterstock/John A Davis</span></span>
</figcaption>
</figure>
<p>Improper disposal of ash from log burners in green bins causes <a href="https://www.sciencedirect.com/science/article/abs/pii/S0269749119331276">arsenic contamination of compost</a>. Deliberate <a href="https://www.rnz.co.nz/news/national/463251/taranaki-composting-plant-flunks-latest-environmental-report">composting of treated timber</a> has also been uncovered. </p>
<p>In a study of 35 countries, New Zealand was the only one where arsenic contamination of residential indoor dust <a href="https://pubs.acs.org/doi/10.1021/acs.est.1c04494">exceeded the non-carcinogenic hazard index</a> for children. </p>
<h2>No safe disposal</h2>
<p>CCA is also an obstacle in the <a href="https://environment.govt.nz/assets/publications/Aotearoa-New-Zealands-first-emissions-reduction-plan.pdf">transition to a circular bioeconomy</a>. Reuse of timber is a well established procedure. It prioritises reuse over thermal utilisation (using it as fuel to harness its energy). </p>
<p>However, there is no viable reuse for CCA-treated timber waste. The problem is even bigger. CCA-treated timber <a href="https://www.ecan.govt.nz/document/download?uri=1879489">cannot be separated from untreated timber</a> in demolition waste. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-create-20m-tons-of-construction-industry-waste-each-year-heres-how-to-stop-it-going-to-landfill-114602">We create 20m tons of construction industry waste each year. Here's how to stop it going to landfill</a>
</strong>
</em>
</p>
<hr>
<p>In New Zealand, CCA-treated timber is to be disposed in secure landfills, forcing future generations to manage the toxic CCA <a href="https://doi.org/10.1021/es051471u">leachate</a>. Burning in appropriate facilities is the only viable disposal method for CCA-treated timber – it is the mandatory disposal option in Germany. However, no sizeable waste incineration plant has been commissioned in New Zealand.</p>
<p>A brief visit to any school, playground, picnic area, domestic garden or DIY shop demonstrates New Zealand’s comparatively relaxed attitude towards CCA. Government and industry state to never burn CCA-treated timber, but this is not communicated to the public effectively.</p>
<p>Recent advice at my local DIY stores included, “yes, it’s standard for playground equipment” and “it can be burned or recycled”. Preservative-treated wood is frequently sold as firewood. At my last check, three out of the top 50 firewood listings on the auction site TradeMe were <a href="https://www.cellulosechemtechnol.ro/pdf/CCT7-8(2022)/p.705-716.pdf">CCA-treated timber waste</a>.</p>
<p>New Zealand’s industry-led approach has failed. The first step to tackle the CCA liability is easy, as alternative preservatives are approved. Restricting the use of CCA-treated timber or introducing a <a href="https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.501.8835&rep=rep1&type=pdf">product stewardship scheme</a> will ensure nothing is added to New Zealand’s CCA legacy. </p>
<p>Ensuring our children do not have to inherit the existing CCA legacy is more difficult. We need to commission a suitable incineration facility.</p>
<p>CCA-treated timber is cheaper than safer alternatives but only if disposal costs are outsourced to future generations.</p><img src="https://counter.theconversation.com/content/199865/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clemens Altaner is Science Team Leader of the New Zealand Dryland Forests Initiative (NZDFI). He has received funding from industry and government for work on naturally durable timber.</span></em></p>
The common timber treatment CCA is made up of heavy metals copper, chromium and arsenic. They don’t decompose and leach into soil and water. Why does New Zealand still allow its use?
Clemens Altaner, Associate Professor in Wood Science, University of Canterbury
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/163222
2021-08-17T13:44:40Z
2021-08-17T13:44:40Z
Tiny plastic residues threaten Atlantic and Guadeloupean oysters
<figure><img src="https://images.theconversation.com/files/414223/original/file-20210802-22-lttbk.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C998%2C688&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Like many marine species, oysters are affected by nanoplastics that pollute the oceans. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Our daily use of plastic products is having direct consequences on the health of animals. Roughly one per cent of plastic waste <a href="http://www.cwhc-rcsf.ca/docs/fact_sheets/Wildlife%20ingestion%20of%20microplastics.pdf">ends up in aquatic and terrestrial environments where it can have negative effects on wildlife</a>.</p>
<p>Among these species are oysters, marine mollusks found in many places around the world — as well as on our dinner plates.</p>
<p>In collaboration with the Centre national de la recherche scientifique at the University of Bordeaux, France, our team at the Institut national de la recherche scientifique conducted research to learn more about the combined effects of nanoplastics and arsenic on oysters.</p>
<p>Earlier laboratory studies have shown that nanoplastics can have negative effects on the <a href="https://doi.org/10.1016/j.envpol.2018.08.020.">ability of Pacific oysters to reproduce</a>. Recently, our research team looked at the individual and combined effects of <a href="https://www.sciencedaily.com/releases/2021/05/210504112641.htm">nanoplastics</a> and <a href="https://www.who.int/news-room/fact-sheets/detail/arsenic">arsenic</a> on oysters, and found these pollutants affected some of their most basic functions. We published the results in <a href="https://doi.org/10.1016/j.chemosphere.2021.130331"><em>Chemosphere</em></a> and <a href="https://doi.org/10.3390/nano11051151"><em>Nanomaterials</em></a>.</p>
<h2>The Atlantic oyster is most affected</h2>
<p><a href="https://www.sciencedaily.com/releases/2021/05/210504112641.htm">Nanoplastics</a> are plastics measuring less than one thousandth of a millimetre across. They <a href="https://doi.org/10.1007/978-3-319-16510-3_12">come largely from the degradation of plastic waste released into the environment</a>, but they can also include plastic nanobeads contained in consumer products, like face scrubs, that find their way into natural environments.</p>
<p>These nanoplastics can accrue a variety of environmental contaminants on their surfaces. When an organism ingests the contaminated nanoplastic, the substance can separate from the plastic and accumulate in the organism’s tissues. </p>
<p>Arsenic, a toxic metal, was the most abundantly measured contaminant on the plastic debris our team collected on the beaches of Guadeloupe. Oysters easily accumulate metals through their diet. </p>
<p>We exposed oyster to an environmentally relevant concentration of arsenic. We measured high concentrations of arsenic in the exposed mollusks, and found higher levels in the gills of the Atlantic oyster <a href="https://animaldiversity.org/accounts/Crassostrea_virginica/"><em>Crassostrea virginica</em></a> than in those of the oyster <a href="https://doi.org/10.1016/j.ecss.2019.106333"><em>Isognomon alatus</em></a> found in Guadeloupe.</p>
<p>These results are the first to highlight the difference in sensitivity of oyster species to arsenic.</p>
<p>We also wanted to test whether the combined exposure of nanoplastics and arsenic would increase the accumulation of this metal in mollusks. Fortunately, this was not the case. <a href="https://www.sciencedirect.com/topics/chemistry/bioaccumulation">The bioaccumulation</a> of arsenic did not increase with the presence of these nanoparticles.</p>
<figure class="align-center ">
<img alt="a Crassostrea virginica oyster bed" src="https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407530/original/file-20210621-26003-bxbst2.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">A Crassostrea virginica oyster bed in the Atlantic Ocean, in the coastal United States.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Effects on the basic functions of oysters</h2>
<p>Oysters are filter feeders that eat small bits of algae suspended in the water. We contaminated algae with three types of nanoplastics to test whether these would cause problems to their health.</p>
<p>The nanoplastics we studied were particles of synthetic carboxylated polystyrene with no additives, crushed particles of virgin polystyrene and soiled plastics. The latter were recovered from the beaches of Guadeloupe and then crushed.</p>
<p>Among these three types of plastics, nanoplastics without additives, which are used in detergents and biocides, were the most toxic to both Atlantic and Guadeloupean oysters. After we exposed the oysters to these plastics, the Atlantic oyster showed increases in the expression of genes associated with programmed cell death, as well as an increase in the number of mitochondria — the cell’s energy centres. The Guadeloupean oyster also showed changes in gene expression, but the response was less pronounced. </p>
<p>The combined exposure to nanoplastics and arsenic revealed contrasting effects between our two oyster species. For example, they reduced the individual effects previously seen on the expression of genes involved in the regulation of <a href="https://www.sciencedirect.com/topics/neuroscience/oxidative-stress">oxidative stress</a>, a situation that creates a toxic environment in the cell. Yet their interaction also amplified certain effects, such as an increase in the production of mitochondria.</p>
<p>Researchers are increasingly using gene expression and other tools of molecular biology to understand the effects of environmental contaminants in animals. It is important to develop ultra-sensitive techniques that warn us, in real time, when a contaminant is affecting the health of ecosystems. We must not wait to reach concentrations of pollutants that would cause irreversible effects.</p>
<figure class="align-center ">
<img alt="a dish of oysters served with sauces and lemon" src="https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407529/original/file-20210621-35622-1othxrv.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">Oysters are found on plates all over the planet. It is therefore essential to know their contaminants.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>In the food web</h2>
<p>The next step is to study how nanoplastics are moved into the food web.</p>
<p>Analytical tools are currently being developed to quantify the presence of nanoplastics in biological tissues. For example, “<a href="https://doi.org/10.1021/acs.est.1c01351">pyrolysis gas chromatography</a>” is an analytical tool that can be used to identify a variety of polymers and contaminants in a sample. </p>
<p>It could be used in the future to help determine the amount of particulate matter found in farmed and wild oysters.</p><img src="https://counter.theconversation.com/content/163222/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Valérie Langlois has received financial support from the Agence nationale de la recherche (ANR), the Centre national de la recherche scientifique (CNRS) and the Canada Research Chairs</span></em></p><p class="fine-print"><em><span>Marc Lebordais has received financial support from the Agence nationale de la recherche (ANR), the Centre national de la recherche scientifique (CNRS) and the Canada Research Chairs</span></em></p>
Nanoplastics and arsenic can affect some of the most basic functions of oysters.
Valérie S. Langlois, Professor/Professeure titulaire, Institut national de la recherche scientifique (INRS)
Marc Lebordais, PhD student at the Cervo Brain Research Centre, Institut national de la recherche scientifique (INRS)
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/146533
2020-09-25T12:23:59Z
2020-09-25T12:23:59Z
Ancient microbial life used arsenic to thrive in a world without oxygen
<figure><img src="https://images.theconversation.com/files/359871/original/file-20200924-18-13kp7nk.jpg?ixlib=rb-1.1.0&rect=71%2C29%2C1374%2C727&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Purple microbial mats offer clues to how ancient life functioned. </span> <span class="attribution"><a class="source" href="https://marinesciences.uconn.edu/person/pieter-visscher/">Pieter Visscher</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Billions of years ago, life on Earth was mostly just large slimy mats of microbes living in shallow water. Sometimes, these microbial communities made carbonate minerals that over many years cemented together to become <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/stromatolite">layered limestone rocks called stromatolites</a>. They are the oldest evidence of life on Earth. But the fossils don’t tell researchers the details of how they formed.</p>
<p>Today, most life is supported by oxygen. But these microbial mats existed for a billion years <a href="https://en.wikipedia.org/wiki/Great_Oxidation_Event">before oxygen was present in the atmosphere</a>. So what did life use instead? </p>
<p>Our team of <a href="https://scholar.google.com/citations?user=Ikl5sOsAAAAJ&hl=en&oi=sra">geologists</a>, <a href="https://scholar.google.com/citations?hl=en&user=dST-ijMAAAAJ">physicists</a> and <a href="https://scholar.google.com/citations?hl=en&user=Wx6rafEAAAAJ">biologists</a> had found hints in fossilized stromatolites that arsenic was the chemical of choice for ancient photosynthesis and respiration. But modern-day versions of these microbial communities still live on Earth today. Perhaps one of these used arsenic and could offer proof for our theory?</p>
<p>So we joined a surveying expedition of Chilean and Argentinian scientists to look for living stromatolites in the extreme conditions of the High Andes. In a small stream deep in the <a href="https://www.livescience.com/64752-atacama-desert.html">Atacama Desert</a>, we found a big surprise. The bottom of the channel was bright purple and made of stromatolite-building microbial mats that thrive in the complete absence of oxygen. Just as the clues we’d found in ancient fossils suggested, these mats use two different forms of arsenic to perform photosynthesis and respiration. Our discovery offers the strongest evidence yet for how the oldest life on Earth survived in a pre-oxygen world.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing how arsenic can function in place of oxygen in photosynthesis and respiration." src="https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359873/original/file-20200924-22-zzmnx4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Modern organisms make oxygen during photosynthesis and use it in respiration, but other elements, like arsenic, shown here as As, can work too.</span>
<span class="attribution"><a class="source" href="https://marinesciences.uconn.edu/person/pieter-visscher/">Christophe Dupraz, Anthony Bouton, Pieter Visscher</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Turning sunlight into energy</h2>
<p>For the last 2.4 billion years, photosynthetic organisms like plants and <a href="https://ucmp.berkeley.edu/bacteria/cyanointro.html">blue-green cyanobacteria</a> have used sunlight, water and carbon dioxide to make oxygen and organic matter. In doing this, they turn energy from the Sun into energy to be used by life. Other organisms breathe in oxygen as they digest organic carbon, gaining energy for their respiration in the process.</p>
<p>Microbes in the ancient world also captured energy from sunlight, but their primitive machinery <a href="https://en.wikipedia.org/wiki/Oxygen_evolution">could not make oxygen from water</a> or use oxygen for respiration. They needed another chemical to do this.</p>
<p>From a biochemical perspective, there are only a few possible candidates: iron, sulfur, hydrogen or arsenic. A lack of evidence in the fossil record and minuscule amounts of some of these chemicals <a href="https://link.springer.com/referenceworkentry/10.1007%2F978-3-662-44185-5_1275">in the primordial soup</a> suggests neither iron, sulfur nor hydrogen would be likely candidates for the earliest form of photosynthesis. That leaves arsenic.</p>
<p>In 2014, our team found the first clue that stromatolites were produced by arsenic-assisted photosynthesis and respiration. We collected pieces of <a href="http://pilbara.mq.edu.au/wiki/Stromatolites">2.72-billion-year-old stromatolites</a> from the pre-oxygen world by drilling into an ancient reefs in <a href="https://www.abc.net.au/news/science/2017-05-10/early-life-on-land-in-3.5bn-year-old-hot-spring-in-pilbara/8497594">the Outback of Australia</a>. We then took these samples to France and cut them into thin slivers. <a href="https://www.synchrotron-soleil.fr/en/beamlines/nanoscopium">By measuring the X-rays that came off these samples when we bombarded them with photons</a>, we made a map of the chemical elements in the sample. If two kinds of arsenic are present in the map, then it is a sign that life was using arsenic for photosynthesis and respiration. In these relics of ancient life we found lots of both forms of arsenic, but not iron or sulfur.</p>
<p>This was tantalizing, but we wanted more proof: a modern analog to help prove our arsenic theory. No researchers had ever found a microbial mat community living in a place completely free of oxygen, but if we found one, it could help explain how the first stromatolites formed when our planet’s oceans and atmosphere were lacking oxygen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Pieter Visscher using a field gear to measure the chemical make up of the purple microbial mats." src="https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359872/original/file-20200924-17-z7a471.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>
<figcaption>
<span class="caption">Samples taken from the microbial mats had high levels of arsenic and lithium, but no oxygen.</span>
<span class="attribution"><a class="source" href="https://marinesciences.uconn.edu/person/pieter-visscher/">D’Angelo Duran</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Modern microbes, ancient analogs</h2>
<p>The Atacama Desert in Chile is the driest place on Earth, flanked by volcanoes and exposed to extremely high UV radiation. It’s not too different from how the Earth looked 3 billion years ago and not exactly supportive of life as we know it. Here – with the help of a team that spanned four continents and seven countries – we found what we were looking for. </p>
<p>Or destination was Laguna La Brava, a very salty shallow lake deep into the harsh desert. A shallow stream, fed by a volcanic groundwater spring, led into the lake. The streambed was a unique, deep purple color. The color came from a microbial mat, thriving quite happily in waters that contained unusually high amounts of arsenic, sulfur and lithium, but missing one important element – oxygen.</p>
<p>Could these slimy purple blobs offer answers to an ancient question?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A purple and brown clump of microbes sitting on a white background." src="https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359874/original/file-20200924-14-117qz8m.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 piece of the microbial mats living at the bottom of the oxygen-free stream.</span>
<span class="attribution"><a class="source" href="https://marinesciences.uconn.edu/person/pieter-visscher/">Pieter Visscher</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We cut a piece of the mat and looked for evidence of minerals. A drop of acid made the minerals fizz – carbonates! – this microbe community was forming stromatolites. So our team went to work, camping out at the site for days at a time. </p>
<p>We measured the chemistry of the water and the mat with our field equipment during day and night, summer and winter. Not once did we find oxygen, and back in the laboratory we confirmed that sulfur and arsenic were abundant. Looking through the microscope, we saw purple photosynthetic bacteria, but oxygen-producing cyanobacteria were eerily absent. We had also collected DNA samples from the mat and found genes for arsenic metabolism. </p>
<p>In the lab, we mixed up microbes from the mat, added arsenic and exposed the mix to sunlight. Photosynthesis was happening. The microbes used both arsenic and sulfur, but preferred the arsenic. When we added a minuscule amount of organic matter, a different arsenic compound was used for respiration and preferred over sulfur.</p>
<p>[<em>You’re too busy to read everything. We get it. That’s why we’ve got a weekly newsletter.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybusy">Sign up for good Sunday reading.</a> ]</p>
<p>All that was left was to show that the two types of arsenic could be detected in the modern stromatolites. We went back to France, and using an X-ray emission technique made chemical maps from the Chilean samples. Every experiment we performed supported the <a href="https://doi.org/10.1038/s43247-020-00025-2">presence of a vigorous arsenic cycle</a> in the absence of oxygen in this unique modern stromatolite. This validates, beyond doubt, the idea that the fossil Australian samples that we studied in 2014 held evidence of an active arsenic cycle in deep time on our young planet. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The large lake of Laguna La Brava with active volcanoes behind at sunset." src="https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359875/original/file-20200924-16-s5sknw.png?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">Laguna La Brava is closer to the Martian environment than most places on Earth.</span>
<span class="attribution"><a class="source" href="https://marinesciences.uconn.edu/person/pieter-visscher/">Pieter Visscher</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Answers on Earth, leads for Mars</h2>
<p>The harsh conditions of the Atacama are so similar to Martian and early Earth environments that <a href="https://www.sciencealert.com/life-rebounds-after-eternity-without-water-earth-s-driest-places-atacama-desert-microbes-mars">NASA scientists and astrobiologists turn to the Atacama</a> to answer questions about how life began on our planet, and how it might start elsewhere. The arsenic-cycling mats we discovered at Laguna La Brava offer strong clues to some of the most fundamental questions about life.</p>
<p>On board the Mars 2020 Perseverance rover that is currently hurtling through space is an instrument that can observe elements using the <a href="https://mars.nasa.gov/mars2020/spacecraft/instruments/pixl/">exact same process we used to make our element maps</a>. Perhaps it will discover that arsenic is abundant in layered rocks on Mars, suggesting that life on Mars also used arsenic. For over a billion years, it did so on Earth. Under the harshest conditions life finds a way, and it is that way <a href="https://doi.org/10.1038/s43247-020-00025-2">we are trying to understand</a>.</p><img src="https://counter.theconversation.com/content/146533/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pieter Visscher receives funding from the National Science Foundation, NASA Exobiology (USA), UBFC-ISITE program (France)</span></em></p><p class="fine-print"><em><span>Brendan Paul Burns and Kimberley L. Gallagher do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
How ancient microbes survived in a world without oxygen has been a mystery. Scientists discovered a living microbial mat that uses arsenic instead of oxygen for photosynthesis and respiration.
Pieter Visscher, Professor of Marine Sciences, University of Connecticut
Brendan Paul Burns, Senior Lecturer, UNSW Sydney
Kimberley L. Gallagher, Adjunct Professor of Chemistry, Quinnipiac University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/139012
2020-06-17T11:19:18Z
2020-06-17T11:19:18Z
Healthier 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 University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/132375
2020-03-05T14:20:42Z
2020-03-05T14:20:42Z
There’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 Washington
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/108807
2019-05-07T11:20:36Z
2019-05-07T11:20:36Z
The deadly, life-giving and transient elements that make up group 15 of the periodic table
<figure><img src="https://images.theconversation.com/files/253989/original/file-20190115-152977-vkt7qa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The red tip on these matches contains phosphorus, which ignites when in contact with oxygen.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/group-red-wooden-matches-standing-burning-288725405?src=eYSqUzfy1HG_Jkkm4ApeAg-1-14">Andrew Rafalsky/Shutterstock.com</a></span></figcaption></figure><p>When you see the periodic table, what comes to mind? The pieces on a scrabble board? Maybe you think about your high school chemistry class. Maybe you think of the colorful table plastered on the wall of a lecture hall in college. Maybe you remember your favorite teacher setting something on fire in the front of the classroom. I am <a href="https://blog.richmond.edu/pollocklab/">an assistant professor of chemistry at University of Richmond</a> and when I hear the phrase “the periodic table,” I think about life. </p>
<p>I think about how the molecules and chemicals that surround us and dictate our everyday activities are made up of the elements on that table – they sustain our life, they bring beauty to the world and they are vital in medicine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=402&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Here is the periodic table with all the elements blocked excepted for the ones in group 15.</span>
<span class="attribution"><span class="source">Julie Pollock</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Each column of the periodic table is called a group. Every member of the group has a similar arrangement of electrons which can result in similar chemical properties. The group 15 elements – nitrogen, phosphorus, arsenic, antimony, bismuth and moscovium – are interesting to me because of their pivotal role in life, as well as in <a href="https://blog.richmond.edu/pollocklab/">my research lab</a>. One element we study is phosphorus because of its integral role in the fate of cells. </p>
<p>But before we get into those details, let’s take a brief look at each of the group 15 elements. They are a unique set in their history, uses and properties. </p>
<h2>Group 15 – giving life and causing death</h2>
<p>Nitrogen (N) in its atmospheric form (N₂) makes up approximately 78% of the air we breathe. When bacteria living within plant roots convert it into a usable form through a process called nitrogen fixation, this elemental form of nitrogen gets incorporated into many compounds that are <a href="https://www.wiley.com/en-us/Essential+Biochemistry%2C+3rd+Edition-p-9781118441688">necessary for life – proteins and DNA, for example</a>. At the bottom of the column is Moscovium (Mc), which is interesting because it doesn’t really exist in nature. It’s a radioactive element that can only be generated in a laboratory and <a href="https://doi.org/10.1038/s41557-018-0185-6">survives for less than a second</a>.</p>
<p>Arsenic (As) may be familiar to you because of its association with poisonings. In 1494, Pico della Mirandola, an Italian humanist philosopher during the Renaissance, was poisoned by arsenic, although the details surrounding his <a href="https://doi.org/10.1016/j.jflm.2018.03.016">early death are still debated</a>. For a long time it was believed that Napoleon Bonaparte died of arsenic exposure in 1821, but after <a href="https://doi.org/10.1373/clinchem.2008.117358">extensive comparisons of preserved hair samples</a> from different stages of his life, researchers concluded the increased levels of arsenic were most likely due to preservation techniques of the time. More recently, the World Health Organization estimated arsenic-contaminated drinking water in Bangladesh <a href="https://www.who.int/ipcs/assessment/public_health/arsenic/en/">resulted in over 9,000 deaths in 2001</a>. How arsenic poisons and kills isn’t completely understood, but there is no doubt that the element causes destruction of vital organs in the human body.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.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">A woman from Sonargaon, Bangladesh, shows palms affected by years of drinking arsenic-laced water.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/a8a68bf484aa458c94cf5ad9bc639ac6/a8a68bf484aa458c94cf5ad9bc639ac6/3/1">AP Photo/ A.M. Ahad</a></span>
</figcaption>
</figure>
<p>When the element antimony (Sb) is combined with three oxygen atoms to form antimony trioxide, it is used extensively as a flame retardant for furniture, carpets, drapes, rubber, plastics and adhesives. Quantities of this molecule in these household products tend to be very small, <a href="http://doi.org/10.17226/9841">and these levels of antimony are regarded as safe</a>. </p>
<p>Bismuth (Bi) is a metal found in the same row of the periodic table as a number of toxic metals; however, compounds containing bismuth are harmless. Bismuth compounds can be found in cosmetics due to their distinctive and desirable silvery shimmer. Even if you haven’t used bismuth-containing personal care products, you have probably encountered it in the well-known antacid Peptobismol®, which is <a href="https://doi.org/10.1038/nchem.609">used to treat upset stomachs</a>, or on the Fourth of July when you are watching fireworks. It is a bismuth compound that causes the crackling sounds of the <a href="https://www.youtube.com/watch?reload=9&v=ix8uHBtxxcE">dragon egg fireworks</a>.</p>
<p>Last, but not least, of the group 15 elements is phosphorus (P). It was discovered in 1669 by the alchemist Hennig Brandt and named from the Greek word “phosphoros,” meaning <a href="https://doi.org/10.1007/s11837-007-0071-y">bringer of light</a>. That’s because when the elemental form interacts with atmospheric oxygen it produces a brilliant light. Chemists figured out how to harness the power of this reaction for the development of matches. The red tip on a match still contains a form of phosphorus today.</p>
<h2>Phosphates – regulating cancer cell fate</h2>
<p>In addition to sparks generated by the element, phosphorus is found in a compound known as a phosphate: phosphorus linked to four oxygen atoms. In cells, when a phosphate molecule is attached to a protein, it can turn on, or activate, the protein so that it can perform its function in the cell – like stimulating growth. </p>
<p>When the phosphate is no longer attached to the protein, the cells stop growing. You can think of it almost like the matches described above – when the phosphate is there, the match can ignite and business can proceed. When the phosphate is removed, the match is just a stick and no light is provided; not as much work can happen in the dark. </p>
<p>In cancerous cells, the <a href="https://doi.org/10.1046/j.0014-2956.2001.02473.x">phosphate status is out of control</a>. Imagine a lot of lit matches and a very bright room that can result in a flurry of activity. This activity can have severe consequences for cells. For example, unregulated growth and migration can lead to cancer. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=303&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=303&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=303&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.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">
<figcaption>
<span class="caption">Phosphorylation in cancer cells: When a protein is phosphorylated, it is like a lit match in a room that leads to cancer cell growth. If the phosphate is removed, the match is extinguished and the cells don’t grow as much.</span>
</figcaption>
</figure>
<p>In <a href="https://blog.richmond.edu/pollocklab/">my laboratory</a> at the University of Richmond, we are interested in understanding these phosphates and one protein in particular that interacts with them. This protein, called MEMO1, is found in high quantities in breast cancer patients and helps the phosphates to always stay attached to proteins. We are trying to understand <a href="https://doi.org/10.1021/acs.biochem.8b00582">how MEMO1 interacts with these phosphates</a> and are developing strategies to disrupt those interactions. </p>
<p>We hope that our work reveals a way to help remove the phosphates to stop the unchecked growth of cells – in other words, to blow out the matches.</p>
<p>So next time you hear the words “periodic table,” please think of life. Think of the molecules that you encounter every moment of every day, think of the medicine that keeps you healthy and think of those of us who are working to understand how to keep you that way.</p><img src="https://counter.theconversation.com/content/108807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Pollock receives research funding from the University of Richmond, the Mary Louise Andrews Award for Cancer Research from the Virginia Academy of Sciences, the Jeffress Memorial Trust and the Beckman Foundation. </span></em></p>
The elements that make up each column of the periodic table share a set of common traits. Here, a chemist describes group 15 and the crucial role phosphorus, in particular, plays in cancer.
Julie Pollock, Assistant Professor of Chemistry, University of Richmond
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/109779
2019-01-31T23:01:08Z
2019-01-31T23:01:08Z
Cleaning up abandoned mines means we all pay the price
<figure><img src="https://images.theconversation.com/files/256708/original/file-20190131-112314-hf0mih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers collect samples from the abandoned tailings that flow into Long Lake, near Sudbury, Ont.</span> <span class="attribution"><span class="source">John Gunn</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The fate of abandoned mines are a familiar problem for those living in communal spaces, with common rooms and shared kitchens: “Who is going to clean up this mess?” and “Who is going to pay for the damages?” </p>
<p>Public lands have the same problem when people dump trash in the bush to avoid paying landfill fees. But cleaning up industrial brownfields, like <a href="https://www.cbc.ca/news2/interactives/children-of-the-poisoned-river-mercury-poisoning-grassy-narrows-first-nation/">the mercury-laden sediments in the English-Wabigoon River near Grassy Narrows First Nation</a> in northwestern Ontario, is a far bigger problem than collecting litter.</p>
<p>We are beginning to see some changes. <a href="https://www.thestar.com/calgary/2019/01/31/supreme-court-of-canada-says-bankrupt-energy-companies-must-clean-up-old-oil-and-gas-wells-before-paying-off-creditors.html">The Supreme Court of Canada has ruled that bankrupt oil and gas companies must meet their environmental commitments</a> before they pay off their creditors. </p>
<p>In the mining sector, there are more than 5,000 abandoned sites in Ontario where the taxpayer is on the hook for the cleanup, ecosystem repairs and dealing with the downstream miseries faced by communities. Ontario has spent about <a href="https://northernontario.ctvnews.ca/environmental-cleanup-continues-at-canada-s-worst-mining-disaster-in-timmins-1.3449983">$75 million to date to clean up the former Kam Kotia Mine</a> near Timmins, Ont. It may be the largest ecological rehabilitation effort in the province. </p>
<p>But the vast majority of abandoned mines have not been dealt with, including a former gold mine south of Sudbury, Ont. where <a href="https://www.thesudburystar.com/2017/06/23/drinking-water-advisory-issued-for-long-lake-residents-3/wcm/1de0ce83-b96c-1b7c-7002-b41327a2c5ea">arsenic is steadily seeping into Long Lake and forcing nearby residents to use bottled water</a>. The mine was closed in 1939 after extracting the equivalent of $63 million worth of gold. One hundred years later, taxpayers are stuck with the costs of a cleanup that has still not started. </p>
<p>Abandoned mine sites represent a dark example of a legacy problem. However, there is increasing evidence that future generations will not be left stuck with the job of solving past problems. Modern mining companies are, for example, now under more stringent regulations. </p>
<h2>Polluters pay</h2>
<p>We’ve used the atmosphere as a dumping ground for carbon dioxide, methane and other greenhouse gases for the past 200 years. Finding a way to clean up the atmosphere dwarfs the challenges presented by abandoned mine sites. But it is the same issue — the tragedy of the commons. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/toxic-leftovers-from-giant-mine-found-in-snowshoe-hares-95849">Toxic leftovers from Giant Mine found in snowshoe hares</a>
</strong>
</em>
</p>
<hr>
<p>It’s hard to know who the culprits are: Who trashed the air we breathe, or triggered the extreme climate events we suffer? Asthma, bronchitis, heat stress, slip-and-fall accidents, flood damage and growing insurance costs are all linked to rising greenhouse gas emissions and climate change. </p>
<p>It is even harder to assign blame when the smog and atmospheric damage are <a href="https://www.usatoday.com/story/news/2019/01/28/california-wildfires-insurance-claims-top-11-4-b-2018/2707446002/">caused by wildfires</a>, or other so-called natural processes such as <a href="https://insideclimatenews.org/news/16012019/permafrost-thaw-climate-change-temperature-data-arctic-antarctica-mountains-study">thawing permafrost</a>. However, lately it seems that we are finally starting to connect the dots, and beginning to accept that humans caused these problems. Now we need to pay the bill. </p>
<p>Well, who should pay? Clearly, if we can identify the culprits — illegal dumpers, polluting companies, inefficient users of fossil fuels — <a href="http://www.lse.ac.uk/GranthamInstitute/faqs/what-is-the-polluter-pays-principle/">they should be the first to pay</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-wealth-tax-forces-those-responsible-for-climate-change-to-pay-for-it-105547">A wealth tax forces those responsible for climate change to pay for it</a>
</strong>
</em>
</p>
<hr>
<p>Citizens already are familiar with covering the costs of shared services, including hospitals, highways and schools, and know the wisdom of investing in the future. We all have to shoulder the responsibility for managing the atmosphere we share by reducing fossil fuel use, supporting and encouraging innovation or simply voting for good government that cares about the future.</p>
<h2>Hidden wealth</h2>
<p>Maybe there’s a silver lining. When you clean up a common room after a party, you might actually find change beneath the cushions or be able to cash in the leftover beer bottles. </p>
<p>Sometimes there is actually lots of value in waste if you are smart enough to harvest it. For example, the <a href="http://gsuinc.ca/">Greater Sudbury Utilities Innovation group</a> is harvesting enough natural gas from the landfill site to heat 14,000 homes, and there are <a href="https://www.thesudburystar.com/2017/07/31/sudburys-mine-tailings-worth-billions/wcm/4525f977-934d-5df3-96bc-5155a6fd230e">millions if not billions of dollars of leftover valuable metals in tailing piles</a> around Sudbury. </p>
<p>The economic benefits and avoided health-care costs from <a href="https://www.greentechmedia.com/articles/read/new-york-cuomo-green-new-deal-clean-energy#gs.y0XpsUqq">investments in the clean-tech industry</a> can also be enormous as we move into the post-fossil fuel world. The alternatives are not pleasant.</p>
<p>Lately report after report has delivered the same message: Time is short. We cannot leave the common room in a mess much longer.</p><img src="https://counter.theconversation.com/content/109779/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Gunn is a Tier 1 Canada Research Chair in Stressed Aquatic Systems who receives funding from NSERC Discovery grants, Canada Research Chair, Mitacs, OCE and Laurentian University and two NSERC CREATE program ( Mine of Knowledge, EcoLac). I am also a principal investigator for an NSERC CRD on carbon sequestration in industrial barrens that has both Glencore and Vale Ltd as funding partners.</span></em></p>
Bankrupt oil and gas companies must clean up old wells, yet taxpayers are still stuck with the bill for abandoned mines.
John Gunn, Canada Research Chair in Stressed Aquatic Systems, Laurentian University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/98358
2018-06-27T10:45:33Z
2018-06-27T10:45:33Z
How we discovered three poisonous books in our university library
<figure><img src="https://images.theconversation.com/files/225100/original/file-20180627-112620-14hp9vy.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/old-books-green-cover-yellowed-pages-1048053595?src=7divbo7EJk1uZ9Tm-xdhCA-4-16">Raman Saurei/Shutterstock.com</a></span></figcaption></figure><p>Some may remember the deadly book of Aristotle that plays a vital part in the plot of Umberto Eco’s 1980 novel <a href="http://www.nybooks.com/articles/1983/07/21/murder-in-the-monastery/">The Name of the Rose</a>. Poisoned by a mad Benedictine monk, the book wreaks havoc in a 14th-century Italian monastery, killing all readers who happen to lick their fingers when turning the toxic pages. Could something like this happen in reality? Poisoning by books?</p>
<p>Our recent research indicates so. We found that three rare books on various historical topics in the University of Southern Denmark’s library collection contain large concentrations of arsenic on their covers. The books come from the 16th and 17th centuries.</p>
<p>The poisonous qualities of these books were detected by conducting a series of X-ray fluorescence analyses (micro-XRF). This technology displays the chemical spectrum of a material by analysing the characteristic “secondary” radiation that is emitted from the material during a high-energy X-ray bombardment. Micro-XRF technology is widely used within the fields of archaeology and art, when investigating the chemical elements of pottery and paintings, for example.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=428&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=428&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=428&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223318/original/file-20180615-85830-o9y0od.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&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 poisonous books.</span>
<span class="attribution"><span class="source">SDU</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Glaring green</h2>
<p>The reason why we took these three rare books to the X-ray lab was because the library had previously discovered that medieval manuscript fragments, such as copies of Roman law and canonical law, were used to make their covers. It is <a href="https://medievalbooks.nl/2015/12/18/x-rays-expose-a-hidden-medieval-library/">well documented</a> that European bookbinders in the 16th and 17th centuries used to recycle older parchments. </p>
<p>We tried to identify the Latin texts used, or at least read some of their content. But then we found that the Latin texts in the covers of the three volumes were hard to read because of an extensive layer of green paint which obscures the old handwritten letters. So we took them to the lab. The idea was to filter through the layer of paint using micro-XRF and focus on the chemical elements of the ink below, for example on iron and calcium, in the hope of making the letters more readable for the university’s researchers. </p>
<p>But XRF-analysis revealed that the green pigment layer was arsenic. This chemical element is among the most toxic substances in the world and exposure may lead to various symptoms of poisoning, the development of cancer and even death.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225105/original/file-20180627-112614-twgyc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Accidents caused by the use of green arsenic, 1859.</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/bdgwyugs?query=arsenic&page=1">© Wellcome Collection</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Arsenic (As) is a ubiquitous naturally occurring metalloid. In nature, arsenic is typically combined with other elements such as carbon and hydrogen. This is known as organic arsenic. Inorganic arsenic, which may occur in a pure metallic form as well as in compounds, is the more harmful variant. The toxicity of arsenic does not diminish with time. </p>
<p>Depending on the type and duration of exposure, various symptoms of arsenic poisoning include an irritated stomach, irritated intestines, nausea, diarrhoea, skin changes and irritation of the lungs.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225102/original/file-20180627-112611-bjz8o6.jpeg?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">
<figcaption>
<span class="caption">Paris Green.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Paris_Green_(Schweinfurter_Gr%C3%BCn).JPG">Chris Goulet/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The green arsenic-containing pigment found on the book covers is thought to be Paris green, copper(II) acetate triarsenite or copper(II) acetoarsenite Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂. This is also known as “emerald green”, because of its eye-catching green shades, similar to those of the popular gemstone. </p>
<p>The arsenic pigment – a crystalline powder – is easy to manufacture and has been commonly used for multiple purposes, especially in the 19th century. The size of the powder grains influence on the colour toning, as seen in oil paints and lacquers. Larger grains produce a distinct darker green – smaller grains a lighter green. The pigment is especially known for its colour intensity and resistance to fading.</p>
<h2>Pigment of the past</h2>
<p>Industrial production of Paris green was initiated in Europe in the early 19th century. Impressionist and post-impressionist painters used different versions of the pigment to create their vivid masterpieces. This means that many museum pieces today contain the poison. In its heyday, all types of materials, even book covers and clothes, could be coated in Paris green for aesthetic reasons. Of course, continuous skin contact with the substance would lead to symptoms of exposure. </p>
<p>But by the second half of the 19th century, the toxic effects of the substance were more commonly known, and the arsenic variant stopped being used as a pigment and was more frequently used as a pesticide on farmlands. Other pigments were found to replace Paris green in paintings and the textile industry etc. In the mid 20th century, the use on farmlands was phased out as well.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=598&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=598&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225107/original/file-20180627-112598-1iqk7ja.jpg?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">‘The Arsenic Waltz’.</span>
<span class="attribution"><a class="source" href="https://iiif.wellcomecollection.org/image/V0042226.jpg/full/full/0/default.jpg">© Wellcome Collection</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In the case of our books, the pigment wasn’t used for aesthetic purposes, making up a lower level of the cover. A plausible explanation for the application – possibly in the 19th century – of Paris green on old books could be to protect them against insects and vermin. </p>
<p>Under certain circumstances, arsenic compounds, such as arsenates and arsenites, may be transformed by microorganisms into arsine (AsH₃) – a highly poisonous gas with a distinct smell of garlic. <a href="https://hyperallergic.com/329747/death-by-wallpaper-alluring-arsenic-colors-poisoned-the-victorian-age/">Grim stories</a> of green Victorian wallpapers taking the lives of children in their bedrooms are known to be factual. </p>
<p>Now, the library stores our three poisonous volumes in separate cardboard boxes with safety labels in a ventilated cabinet. We also plan on digitising them to minimise physical handling. One wouldn’t expect a book to contain a poisonous substance. But it might.</p><img src="https://counter.theconversation.com/content/98358/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>
Interdisciplinary research led to the discovery that three historic books were covered in a layer of arsenic.
Jakob Povl Holck, Research Librarian, University of Southern Denmark
Kaare Lund Rasmussen, Associate Professor in Physics, Chemistry and Pharmacy, University of Southern Denmark
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/95849
2018-06-13T23:12:22Z
2018-06-13T23:12:22Z
Toxic leftovers from Giant Mine found in snowshoe hares
<figure><img src="https://images.theconversation.com/files/221847/original/file-20180605-119847-bo5590.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Snowshoe hares near the now closed Giant Mine outside of Yellowknife, N.W.T show signs of arsenic contamination.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/denalinps/6990916044">(Denali NPS/flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Even though it was closed decades ago, the Giant Mine on the outskirts of Yellowknife has left a long environmental legacy. </p>
<p>The gold extraction process, which required roasting ores at extremely high temperatures, created a toxic byproduct called arsenic trioxide. For about 55 years (1948-2004), arsenic and other toxic elements were released into the environment, causing <a href="http://www.rcinet.ca/eye-on-the-arctic/2016/08/24/arsenic-contamination-persists-in-yellowknife-lake-a-decade-after-gold-mine-shut-study/">widespread contamination of the terrestrial and aquatic ecosystems around Yellowknife</a>. </p>
<p>About <a href="http://www.cbc.ca/news/canada/north/giant-mine-arsenic-process-1.4418862">237,000 tonnes of arsenic trioxide dust is buried</a> underground, and <a href="http://www.cbc.ca/news/canada/north/dots-lakes-arsenic-nwt-yellowknife-water-1.4230597">several nearby lakes show arsenic contamination</a>. </p>
<p>Elevated arsenic levels have also been reported in soil, vegetation and fish around Yellowknife, but we knew little about how it has affected the health of the small mammals that live in the area. </p>
<p>Many of these fur-bearing animals are still being trapped for their pelts and for food, so knowing their arsenic levels is also important for human health.</p>
<h2>Weak bones</h2>
<p>Small mammals can serve as sentinels for environmental contamination. Snowshoe hares (<em>Lepus americanus</em>) live in a relatively small area and eat soil, so they are likely to accumulate higher levels of arsenic and other trace metals from the environment. </p>
<p>Exposure to elevated levels of arsenic can cause damage to the liver and other organs. And cadmium, a toxic metal and another byproduct of the gold extraction process, can replace calcium in the bones, leading to bone deformities and weakness. </p>
<p>In humans, chronic arsenic exposure (usually from water) can lead to <a href="https://www.epa.gov/sites/production/files/2014-03/documents/human_health_effects_from_chronic_arsenic_poisoning_3v.pdf">changes in skin colour, skin growths and cancers of the skin, lung and internal organs</a>.</p>
<p>When we measured arsenic and cadmium levels in hares living within two kilometres of the Giant Mine and compared them to hares living about 20 kilometres away from Yellowknife, the results were striking. </p>
<p>The arsenic levels in the guts of snowshoe hares living near the Giant Mine were <a href="https://www.sciencedirect.com/science/article/pii/S0048969717322982">20-50 times greater</a> than those living away from it. We also saw higher concentrations of arsenic in the organs and nails of the Giant Mine hares. </p>
<p>Cadmium levels were also higher but the difference wasn’t as marked. Hares from both locations had weaker bones and showed signs of osteoporosis, probably due to <a href="https://academic.oup.com/toxsci/article/82/2/468/1656953">chronic exposure to cadmium</a>. </p>
<h2>Ecological implications</h2>
<p>This chronic exposure to elevated levels of arsenic and cadmium may explain why snowshoe hares living near the Giant Mine are in poor health. </p>
<p>Wildlife living in metal contaminated areas in other parts of the world have also shown problems with reproduction, osteoporosis, neurological damage and chronic metabolic disease. But in Canada, it’s the first time we’ve seen small wild mammals with chronic arsenic poisoning.</p>
<p>The high levels of pollutants could compromise the long-term survival of the snowshoe hare and other small mammals in the Yellowknife area. </p>
<p>The high arsenic and cadmium burden in hares could have consequences for other animals that prey on them, such as foxes, wolves or other carnivorous mammals, and <a href="https://www.aadnc-aandc.gc.ca/eng/1524242446493/1524243007228">for the people who hunt them</a>.</p><img src="https://counter.theconversation.com/content/95849/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr. Som Niyogi is a Professor at the Department of Biology and an associate faculty of Toxicology Program, University of Saskatchewan. He receives research funding from the Aurora Research Institute, and Natural Sciences and Engineering Research Council (NSERC) of Canada. </span></em></p><p class="fine-print"><em><span>Dr. Solomon Amuno is adjunct professor at the School of Environment and Sustainability, University of Saskatchewan. He receives funding from the Aurora Research Institute.</span></em></p>
Historical gold mining at the Giant Mine near Yellowknife, N.W.T. released toxic arsenic into the environment. Snowshoe hares are showing signs of poisoning.
Som Niyogi, Professor, University of Saskatchewan
Solomon Amuno, Adjunct Professor, University of Saskatchewan
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/56089
2016-04-12T10:26:37Z
2016-04-12T10:26:37Z
Handle with care – the world’s five deadliest poisons
<figure><img src="https://images.theconversation.com/files/118322/original/image-20160412-15871-l2cy2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Terrible by name ... Phyllobates terribilis</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lwpkommunikacio/22591477950/in/photolist-8MCNG1-ek4cuf-dRs6nF-dRxDBA-dbaPBD-4gS8Rq-6zgDtX-aaXPpU-aaUZea-6wvJGh-6wgLdn-dRs6kD-8yBW8N-nutDN2-dSjE7C-8yyQYg-8yBUyu-dSe5a6-dSe5ir-dSe5cp-6LyZad-dSjErh-dSjEjJ-dSjEaq-6KBXyQ-6KBWbE-nNKav6-Aqkejw">Lwp Kommunikáció/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>When asked to name a poison, people may well think of cyanide, arsenic or strychnine. But these are not the most toxic substances known. More poisonous than these, but still not near the top of the tree, is <a href="http://www.chm.bris.ac.uk/motm/ttx/ttx.htm">tetrodotoxin</a>, the pufferfish toxin that poisons around 50 Japanese people every year. The fish is a delicacy in Japan, but can be lethal if prepared incorrectly. Incidentally, this was the poison favoured by evil assassin Rosa Klebb in James Bond film <a href="http://www.007james.com/articles/james_bonds_top_10_close_shaves_part_2.php">From Russia With Love</a>. It also crops up in the <a href="http://www.thecephalopodpage.org/bluering2.php">blue-ringed octopus</a> and was more recently discovered in <a href="https://theconversation.com/the-deadly-poison-lurking-in-a-frog-the-size-of-your-fingernail-43020">tiny frogs in Brazil</a>. </p>
<p>The LD50 (Lethal Dose, 50%) – the amount needed to kill 50% of the test population – is how toxicity is most often assessed, and is usually quoted per kilogram of body weight. On this scale, for example, sodium cyanide comes out at around 6 milligrams per kg. The LD50 of tetrodoxotin, by comparison, is around 300 micrograms per kg if orally ingested, and as little as 10 micrograms per kg if injected.</p>
<p>Assessing toxicity is not easy. The chemical state of a substance is important, as is how we ingest it. If we swallowed liquid mercury metal (as distinct from inhaling the vapour), it would very likely <a href="http://berkeleysciencereview.com/toxic-mercury/">pass straight through us harmlessly</a>. And yet when in 1996 an American professor got just a drop or two of the compound dimethyl mercury on her rubber gloves, it penetrated the gloves and her skin, sending her into a <a href="http://www.chm.bris.ac.uk/motm/dimethylmercury/dmmh.htm">fatal coma some months later</a>. </p>
<p>Nevertheless, here is a representative selection, in ascending order, of five truly deadly poisons, all at least a hundred times more toxic than cyanide, arsenic or strychnine.</p>
<h2>5. Ricin</h2>
<p>This extremely toxic plant poison was famously used to kill the Bulgarian dissident <a href="http://news.bbc.co.uk/onthisday/hi/dates/stories/september/11/newsid_2514000/2514187.stm">Georgi Markov</a>, exiled in London. On September 7 1978, he was waiting for a bus near Waterloo Bridge, when he felt an impact on the back of his right thigh. Looking round he saw a man bending down to pick up an umbrella. Markov was soon taken to hospital with a high fever – and died three days later. An autopsy revealed a tiny sphere made of a platinum-iridium alloy in Markov’s thigh. The sphere had been drilled to take a small amount of ricin and may have been fired from an air gun hidden in the umbrella.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118323/original/image-20160412-15864-fcnv98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ricinus communis: find ricin here.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/museumdetoulouse/10588323154/in/photolist-h8DVzL-dqAhE9-9Dfv5P-bWD4Jw-bWD9NY-8h7tRs-bD38ou-5ssdke-bd67WP-f31ZbY-szRqK-j2HUb4-74Jh44-5jiZz5-ymioDY-dj18gF-diVJSG-CWX9Yu-5jj58u-kyCiVB-9Dfvfg-ARAMzn-dqAbVX-Enchj7-fbmtHY-5jj691-dDshz3-D1xW6k-DgN3KT-az9JsH-CrykKU-j2HR92-6y9ksw-D11NWo-DstHhA-DtKvry-DAeZ9y-CFf9ej-8TgGzn-DXXg1v-oRipi2-DsKapJ-DMwJzf-h9a2Vo-9LJpKH-9ByA7o-DXfQn6-Eistwk-nwxwRz-netN1Y">Muséum de Toulouse/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="http://www.newyorker.com/tech/elements/the-science-of-ricin">Ricin</a> is obtained from the beans of the castor oil plant (Ricinus communis), which is cultivated to extract the oil – the ricin remains in the solid fibre. It is a glycoprotein that interferes with protein synthesis in the cell, <a href="http://www.rsc.org/chemistryworld/podcast/CIIEcompounds/transcripts/ricin.asp">causing cell death</a>. It has an LD50 of 1-20 milligrams per kg if orally ingested, but far less is required to kill if inhaled or injected (as in Markov’s case).</p>
<h2>4. VX</h2>
<p>The only synthetic compound in our top five, VX is a nerve agent with the consistency of engine oil. It emerged from ICI’s research into new insecticides in the early 1950s but proved too toxic to use in agriculture. VX kills by interfering with the transmission of nerve messages between cells; this requires a molecule called acetylcholine. After acetylcholine has passed on its message, it needs to be broken down (otherwise it will keep sending the message) by an enzyme catalyst called acetylcholinesterase. VX and other nerve agents stop this enzyme from working, so muscle contractions go out of control and you die of asphyxiation. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/seZmxDSrieM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Nerve agents explained.</span></figcaption>
</figure>
<p><a href="http://www.rsc.org/chemistryworld/2013/06/vx-sarin-tabun-nerve-weapon-podcast">Nerve agents</a> were made by both sides during the <a href="http://www.compoundchem.com/2015/02/19/nerveagentspart2/">Cold War</a>, but VX became particularly well-known after featuring in Hollywood blockbuster film <a href="http://youtube-downloader-mp3.com/watch-the-rock-sarin-gas-chamber-id-gMVnCL50SgQ.html?similar">The Rock</a>. Only one person is known to have been killed by VX, a former member of the <a href="https://en.wikipedia.org/wiki/Aum_Shinrikyo">Aum Shinrikyo cult</a>, though some 4,000 sheep were killed by it in an accident in Skull Valley, Utah in 1968. It has an LD50 of as little as 3 micrograms per kg (although some reports suggest the figure is a little higher).</p>
<h2>3. Batrachotoxin</h2>
<p>We’ve all heard of South American Indians using venom-tipped blowpipes to hunt their prey. Curare is the best known, and comes <a href="http://ethnobotany09.providence.wikispaces.net/Curare">from a plant</a>. The most toxic, however, come from the skins of tiny frogs – and the deadliest of all is <a href="http://www.chm.bris.ac.uk/motm/batrachotoxin/batrah.htm">Batrachotoxin</a>.</p>
<p>Native Indians in Western Colombia collect these frogs – golden <em>Phyllobates terribilis</em> and multicoloured <em>Phyllobates bicolor</em> – and sweat out the poison over a fire before putting it on their darts. The LD50 is around 2 micrograms per kg, meaning that an amount the size of two grains of table salt will kill you. </p>
<p>Batrachotoxin kills by interfering with sodium ion channels in the cells of muscles and nerves, jamming them open so that they do not close. The continued migration of Na+ ions results ultimately in <a href="http://www.rsc.org/chemistryworld/2014/02/batrachotoxin-poison-dart-frog-podcast">heart failure</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/TjTOJ6zIbys?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A very poisonous bird.</span></figcaption>
</figure>
<p>Interestingly, captive-born frogs of these species are not poisonous, suggesting that the poison is derived from their diet. Indeed, nearly 30 years ago, <a href="http://www.jackdumbacher.com/blog">Jack Dumbacher</a>, an American ornithologist, was working in Papua New Guinea when he was scratched on the hand by one of the local Pitohui birds. He instinctively put his hand to his mouth, which started to go numb. Eventually, it was found that these birds – on the opposite side of the world to Colombia – have plumage containing the same poisonous molecule as the frogs. It is thought that both the birds and frogs obtain the toxin from the beetles they eat – although the poison is far less potent in the birds</p>
<h2>2. Maitotoxin</h2>
<p>There are a number of potent <a href="http://www.mdpi.com/1660-3397/6/2/349/htm">marine toxins</a>, such as Saxitoxin, which are often the cause of poisoning after <a href="http://www.cdc.gov/ncidod/dbmd/diseaseinfo/marinetoxins_g.htm">eating contaminated shellfish</a>. These are often associated with harmful <a href="http://onlinelibrary.wiley.com/doi/10.2310/7060.2003.30550/pdf">algal blooms in the sea</a>.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=518&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=518&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118324/original/image-20160412-15853-100y5s8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=518&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dinoflagellate.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fickleandfreckled/6939384773/in/photolist-bzdak4-5q1gF3-mxwfYA-5pVNDz-mxpLBX-dmM7bt-8Nreaj-c6uHfL-rddRJJ-qxZRgB-rdcRWC-ruFLrG-rdd6Tq-qxZGFa-rbsZee-aFcoi3-qwAB1L-rde7ru-ruM1TR-qxN7UL-qxMVXA-ragJUk-rdd6FS-rc2yDj-ruFoKp-ruMn1e-ruFRRE-rsuERG-ruF5Nc-8ZASTe-fKxgky-qxN71S-ragM4k-ruMC8Z-rsuie3-qy1cxZ-rdkA7r-ruG7vj-ruF5pM-rdkKvX-bsB5BB-bsB5V8-bsB5S6-nHHCGJ-nttowW-nGw5XN-nG7viP-nep7ne-nf3Uow-newPgL">fickleandfreckled/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Maitotoxin is the most lethal of these substances, reckoned to have a LD50 about an order of magnitude less than batrachotoxin. Formed by a dinoflagellate, a kind of marine plankton, it has a very complicated structure, which presents a massive challenge to synthetic chemists. Maitotoxin is a cardiotoxin, it exerts its effects by increasing the flow of calcium ions through the <a href="http://www.rsc.org/chemistryworld/2015/01/chemistry-grandest-total-synthesis-challenge-maitotoxin-put-hold-lack-funds">cardiac muscle membrane</a>, causing heart failure.</p>
<h2>1. Botulinum toxin</h2>
<p>Scientists differ about the relative toxicities of substances, but they seem to agree that <a href="https://theconversation.com/explainer-the-good-the-bad-and-the-ugly-of-botulinum-toxin-16728">botulinum toxin</a>, produced by anaerobic bacteria, is the <a href="http://www.chm.bris.ac.uk/motm/botulism/both.htm">most toxic substance known</a>. Its LD50 is tiny – at most 1 nanogram per kilogram can kill a human. Extrapolating from its effect on mice, an intravenous dose of just 10<sup>-7</sup>g would be fatal to a 70kg person.</p>
<p>It was first identified as a cause of food poisoning due to incorrectly prepared sausage (Latin, <em>botulus</em>) in late-18th century Germany. There are several botulinum toxins, with type A being the most potent. These are polypeptides, consisting of over 1,000 amino acid molecules joined together. They cause muscle paralysis by preventing the release of the signalling molecule (neurotransmitter) acetylcholine.</p>
<p>This same paralysing property is fundamental to the clinical use of the botulinum toxin in cosmetic <a href="https://www.nlm.nih.gov/medlineplus/botox.html">Botox</a>. Targeted injections of tiny amounts of the toxin stop particular muscles from working, relaxing muscles that would otherwise cause wrinkly skin. But it has also been applied to a range of clinical conditions, such as paralysing muscles that, if untreated, would cause crossed eyes (strabismus).</p>
<p>There is increasing interest in using the properties of toxic substances medicinally. The venom of the lethal Brazilian pit viper, <em>Bothrops jararaca</em>, for example, contains blood-pressure reducing molecules that have led to pioneering treatments for <a href="http://blogs.discovermagazine.com/loom/2011/03/11/how-a-pit-viper-saved-millions-of-lives-snakes-as-drug-factories/#.VwZEgPkrLcs">high blood pressure</a>.</p>
<p>As Paracelsus is reported to have said 500 years ago: “All things are poison, and nothing is without poison: the dose alone makes a thing not poison.” And he had a point. Ultimately, we are surrounded by potentially dangerous substances – it’s the dose that makes it deadly.</p><img src="https://counter.theconversation.com/content/56089/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Cotton 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>
Don’t forget to wash your hands.
Simon Cotton, Senior Lecturer in Chemistry, University of Birmingham
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/49075
2015-10-28T04:30:40Z
2015-10-28T04:30:40Z
Africa’s aquifers aren’t being protected as they should
<figure><img src="https://images.theconversation.com/files/99330/original/image-20151022-5653-fjwagk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Despite the noble intentions behind charity wells, they may not be the best thing.</span> <span class="attribution"><span class="source">Franco Volpato/Shutterstock</span></span></figcaption></figure><p>NGOs often <a href="http://thewaterproject.org/digging-wells-in-africa-and-india-how-it-works">punt</a> the digging of wells as the solution to the long distances women in rural areas travel to collect water. These wells do improve the <a href="http://thewaterproject.org/health">quality of life</a>, but care needs to be taken in digging them as they could lead to the over-exploitation of aquifers. </p>
<p>It is true that wells have been advocated because they are easy to use, and because of the perception that groundwater is omnipresent. Also, the cost of sinking a well in comparison to other water supply infrastructure is <a href="http://www.kgs.ku.edu/Publications/PIC/pic23.html">minimal</a>.</p>
<p>But the <a href="http://www.iied.org/">International Institute for Environment and Development</a> has said that up to US$360 million has been spent on rural water supply schemes which are now <a href="http://pubs.iied.org/17055IIED.html">dysfunctional</a>. This equates to approximately 50,000 water points or pieces of infrastructure that have been installed and no longer <a href="https://rwsnblog.wordpress.com/2014/06/26/4-lessons-about-handpump-sustainability-in-ghana/">work</a>. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/99331/original/image-20151022-5653-16es577.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">Research shows that large numbers of these well are left unused.</span>
<span class="attribution"><span class="source">Patrick Poendl/Shutterstock</span></span>
</figcaption>
</figure>
<p>In Bangladesh, for example, NGOs have pushed for wells to be dug. But recent <a href="http://news.nationalgeographic.com/news/2003/06/0605_030605_arsenicwater.html">research</a> suggests that human alteration to the landscape, the construction of ponds, and the adoption of irrigated agriculture are responsible for a pattern of increased arsenic concentration underground.</p>
<p>Added to this is the problem of unsustainable extraction. This takes place through a myriad of ways. The consequences can be devastating.</p>
<p>Sadly this is the only water people in the region have. They are forced to drink it and suffer from callouses on their hands and feet <a href="http://web.mit.edu/harvey-lab/Arsenic_in_Bangladesh.html">caused by</a> the arsenic.</p>
<p>A similar situation occurred in a small South African town a few years ago. Studies completed in the area noticed a decline in groundwater levels by as much as 25 metres over a period of 20 years due to unsustainable <a href="http://etd.uwc.ac.za/xmlui/handle/11394/2539">extraction</a>. The situation was so dire that calls were made for people passing through to transport water into the town. </p>
<h2>The Cinderella of water resources</h2>
<p>Aquifers across Africa are critical for potable water supply and help contribute as much as 70% of the total water supply in some <a href="http://apps.unep.org/publications/pmtdocuments/Groundwater_pollution_in_Africa.pdf">countries</a>. The management of these is critical.</p>
<p>For example, groundwater supplies the majority of small towns in South Africa, yet almost none of the municipalities employ a hydrogeologist on a full-time <a href="https://www.dwa.gov.za/Groundwater/Documents/GSDocument%20FINAL%202010_MedRes.pdf">basis</a>. This has led to the mismanagement of the subsurface water reserve and, in certain instances, the deterioration of groundwater quality and mining of aquifers.</p>
<p>A number of technical factors need to be taken into account on a site by site basis to make sure that groundwater is extracted sustainably.</p>
<p>It is a common misconception that when we drill, we tap into a river <a href="http://www.swissharmony.com/what-are-water-veins/">underground</a>. This is not the case. </p>
<p>Ground water moves slowly through, or is stored in, permeable rocks called aquifers. An aquifer may be a layer of almost any kind of gravel, sand or rock that has spaces between the pores able to hold moisture. The connectivity of these pores and the size of the pore, or cavity, will determine the ability to extract water from the subsurface. </p>
<p>There is a case to be made for and against using underground water. But monitoring is critical. The problem is that monitoring stations are regularly closed down and less data is available to manage the <a href="http://www.un-igrac.org/download/file/fid/288Yet">resource</a>.</p>
<p>The situation becomes critical when emergency supplies are needed and the groundwater reserves are able to replenish the already depleted surface water reserves. When the need arises, the automatic response is to pump groundwater to supplement surface water, but without the necessary management and monitoring systems in place.</p>
<h2>Working together for water</h2>
<p>A decentralised approach to managing the resource has been taken in certain African countries. For example, in West Africa, money is collected regularly from the users of a supply well in a village to help finance the maintenance of the well. </p>
<p>This approach doesn’t always work. The International Institute for Environment and Development has shown that nepotism is rife and the mismanagement of finances on such a small scale is <a href="http://www.undp.org/content/dam/undp/library/Democratic%20Governance/IP/Anticorruption%20Methods%20and%20Tools%20in%20Water%20Lo%20Res.pdf">common</a>.</p>
<p>In essence, a more co-ordinated effort is required which involves government, NGOs, academia and the private sector to sustainably develop and manage groundwater. This means that <a href="https://www.dwa.gov.za/groundwater/FAQ.aspx">licensing</a>, as exists in South African legislation, is needed prior to sinking a well or borehole for water supply or irrigation purposes.</p><img src="https://counter.theconversation.com/content/49075/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gaathier Mahed receives funding from CPUT. </span></em></p>
The digging of wells in Africa has often been thought of as the solution to helping rural women walking to get water, but they may cause more harm than good.
Gaathier Mahed, Hydrogeologist, Researcher and Senior Lecturer , Cape Peninsula University of Technology
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/41876
2015-06-02T10:12:05Z
2015-06-02T10:12:05Z
What does exposure to environmental chemicals mean for our health?
<figure><img src="https://images.theconversation.com/files/83585/original/image-20150601-6967-1ywo4zf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Environmental chemicals are found in a range of common household products. </span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-85926235/stock-photo-image-of-many-plastic-bottles-with-water-in-a-shop.html?src=VohMyolLWzvRSkwCCzAqNg-1-3">Water bottles via www.shutterstock.com.</a></span></figcaption></figure><p>It is not possible to live in a <a href="https://theconversation.com/five-myths-about-the-chemicals-you-breathe-eat-and-drink-26849">chemical-free world</a> on Earth. Chemicals are all around us, and some, <a href="http://www.sciencedaily.com/releases/2014/06/140605140007.htm">like oxygen and hydrogen</a>, are essential components for <a href="http://ec.europa.eu/environment/chemicals/index_en.htm">living creatures</a> including us humans. However, some other chemicals may be harmful to our health. </p>
<p>Some environmental chemicals (which are often, but not always, human-made) have been linked to physical and cognitive health conditions and even <a href="http://www.clinicalepigeneticsjournal.com/content/7/1/55">DNA change</a>. Many of these chemicals, such as arsenic, phthalates, polyfluoroalkyl and volatile organic compounds, to name a few, are found in a range of common household or industry products that we use or are exposed to on a regular basis, including cleaning supplies, car exhaust and certain kinds of cosmetics.</p>
<h2>How do we study exposure to environmental chemicals and health?</h2>
<p>One of the prime sources for data on exposure to environmental chemicals and human health comes from the National Health and Nutrition Examination Surveys (<a href="http://www.cdc.gov/nchs/nhanes/about_nhanes.htm">NHANES</a>). </p>
<p>This is a program of epidemiological studies run by the US Centers for Disease Control and Prevention. NHANES monitors the health status of adults and children in the US with a representative sample and uses both interviews and physical examinations. </p>
<p>Some of the information collected includes urine and blood samples, which we can use to track exposure to environmental chemicals. This gives us a picture of the emerging risk hazards from chemicals – we can test the volume of a given chemical in urine or blood and see what the associations are with a range of health conditions. Researchers have been doing this since the 1980s, and scores of studies have been released detailing the associations between concentrations of environmental chemicals in the body and different health outcomes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=536&fit=crop&dpr=1 754w, https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=536&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/81767/original/image-20150514-28638-r5gomg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=536&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Overview of main health effects on humans from some common types of pollution.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:Health_effects_of_pollution.png">Medical gallery of Mikael Häggström 2014</a></span>
</figcaption>
</figure>
<h2>Effects on physical health</h2>
<p>The association between exposure to these kinds of chemicals and human health has been well documented in research using data from NHANES. While many environmental chemicals have been studied, I’ll focus on a few chemicals that are fairly well-known.</p>
<p>Looking at NHANES data from 2009-2010, I found an association between <a href="http://informahealthcare.com/doi/abs/10.3109/08037051.2014.925228">high blood pressure</a> in adults and higher concentrations of heavy metals, arsenic and phthalates in urine. Other research has also associated higher urinary arsenic concentrations that could be found in contaminated groundwater or in foods (eg, grains) with impaired <a href="http://www.sciencedirect.com/science/article/pii/S0013935115001085">kidney function</a> and <a href="http://www.sciencedirect.com/science/article/pii/S016041201400350X">gout disease</a>.</p>
<p>Bisphenol-A and triclosan, used in consumer products including soaps, detergents, toys and surgical cleaning treatments, among other things, have been found to affect <a href="http://ehp.niehs.nih.gov/1002883/">immune function</a> and the <a href="http://ehp.niehs.nih.gov/1104748/">age at which menstruation starts</a>.</p>
<p>Phthalates, a chemical that makes plastic and vinyl more flexible, are found in plastic bottles and in pharmaceutical pills and cosmetics. They have been found to play a role in <a href="http://www.ehjournal.net/content/7/1/27">increased body mass index</a>, <a href="http://www.ehjournal.net/content/13/1/6">diabetes</a>, <a href="http://pediatrics.aappublications.org/content/early/2013/08/13/peds.2012-4022">worse insulin resistance</a>, higher <a href="http://ehp.niehs.nih.gov/1206211/">allergy</a> rates and <a href="http://press.endocrine.org/doi/abs/10.1210/jc.2014-2555?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed">decreased testosterone</a> in both adults and children. </p>
<p>Environmental chemicals may be associated with oral health problems as well.
In a recent study, I found that people with <a href="http://link.springer.com/article/10.1007/s11356-015-4749-3">gum disease, bone loss around the mouth, and teeth loose not due to injury</a> were found to have higher levels of heavy metals, phthalates, phenols, parabens and pesticides (among other chemicals) in their urine. Such harmful exposure could cause defects in the development of <a href="https://www.jstage.jst.go.jp/article/pjab/85/10/85_10_500/_article">tooth enamel</a>.</p>
<h2>Environmental chemicals in the brain</h2>
<p>Environmental chemicals could also influence brain development, particularly in children and older adults. </p>
<p>For example, frequent use of household products with higher levels of pyrethroid insecticides and polyfluoroalkyl chemicals are linked to <a href="http://www.karger.com/?DOI=000342310">learning problems</a> and <a href="http://ehp.niehs.nih.gov/1001898/">impaired attention</a> in children. </p>
<p>In the elderly, <a href="http://www.sciencedirect.com/science/article/pii/S016041201200253X">vision, hearing and balance</a> might be altered through chronic exposure to a range of chemicals including heavy metals, phthalates, arsenic, pesticides, phenols, hydrocarbons and polyfluorinated compounds. And it has been further observed that these chemicals might lead to <a href="http://link.springer.com/article/10.1007%2Fs11356-015-4261-9">difficulties in thinking or remembering</a> as well. It is thought that these chemicals may <a href="http://informahealthcare.com/doi/abs/10.1081/DCT-200039780%20">disrupt nerve regulation</a> in the brain.</p>
<h2>Effects on emotions</h2>
<p>If environmental chemicals could impair our organs and change our <a href="http://www.jimmunol.org/content/135/2/820.long">nervous system</a>, then they might have effects on our emotional health as well. </p>
<p>In recent research, I found that higher levels of parabens and polyaromatic hydrocarbons in urine might suggest that some people need more <a href="http://link.springer.com/article/10.1007%2Fs11356-015-4561-0">emotional support</a>, such as talking over problems or help making difficult decisions, than others with lower concentrations do. Such relationship exists whether or not people might have other health conditions. </p>
<p>These chemicals are both quite common. Parabens are often used as preservatives in cosmetic and pharmaceutical products, and polyaromatic hydrocarbons are found in exhaust, asphalt, coal tar, smoke, soil and charbroiled foods. </p>
<p>These chemicals may trigger a physical reaction that ultimately leads to the disruption of emotions. Daily exposure to these chemicals could lead to a person developing a dependency on them. This can induce inflammation or immune function to alert cell injury or damage. And that could, in turn, chronically disturb neuron functioning, leading to the <a href="http://www.jimmunol.org/content/135/2/820.long">disruption of emotions</a>, and hence a need for more emotional support. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/82292/original/image-20150519-30528-3j2xkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We can’t live in a chemical-free world.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-150303686/stock-photo-row-of-modern-townhouses-in-vancouver-canada.html?src=b0MSJm-Iz_MyRdqxtf0yrQ-1-23">Homes via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>How do we know when we are exposed to unnecessary environmental chemicals?</h2>
<p>Once we know the relationships of harmful chemicals and health, we can start to figure out how to lessen or prevent exposure to these chemicals. This could mean reducing our use of the consumer products that contain these substances.</p>
<p>Buildings <a href="http://link.springer.com/article/10.1007%2Fs11356-014-3468-5">built more than 30 years ago</a> could be another source of exposure and therefore need our attention to renovate. They could emit chemicals that harm our health because they have building materials that may contain these harmful chemicals or have other pollutants like <a href="http://www.sciencedirect.com/science/article/pii/S0013935115000304">mold</a>.</p>
<p>A <a href="http://omicsgroup.org/journals/building-engineering-epidemiology-northern-ireland-house-condition-survey-2168-9717.1000112.php?aid=21453">screening program</a> is one of the ways to identify housing and chemical issues at an early stage. </p>
<p>Another way is through an <a href="http://link.springer.com/article/10.1007/s11356-015-4671-8">unpleasant smell</a> which is exactly what it sounds like. The presence of unpleasant odors might direct us to where the excess chemicals around us are. These issues could also be detected by reviewing <a href="http://link.springer.com/article/10.1007/s11356-015-4604-6">self-rated health</a>. This is an indicator of physical and mental health issues, created by asking people questions about their health. </p>
<p>And based on new research about environmental chemicals and oral health, one could also <a href="http://link.springer.com/article/10.1007/s11356-015-4749-3">look at teeth</a> from time to time. </p>
<p>These types of preventative measures could be carried out on a regular basis for individuals and each household to suggest when to examine and remove the unnecessary environmental chemicals in order to improve and sustain our health, well-being and quality of life.</p><img src="https://counter.theconversation.com/content/41876/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ivy Shiue (Scthiue) 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>
Chemicals in a wide array of consumer products have been linked to conditions affecting physical, cognitive and emotional health.
Ivy Shiue (Scthiue), Senior research associate, Northumbria University, Newcastle
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/40732
2015-05-07T09:51:49Z
2015-05-07T09:51:49Z
Are we eating too much arsenic? We need better tests to know
<figure><img src="https://images.theconversation.com/files/80535/original/image-20150505-954-h2gyh8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How much of the harmful arsenic does it have?</span> <span class="attribution"><span class="source">rice via www shutterstock com</span></span></figcaption></figure><p>Researchers have known for some time that the food and drink we all consume contains <a href="http://onlinelibrary.wiley.com/book/10.1002/9781444308785">arsenic</a>.</p>
<p>Should we be concerned? Aren’t we protected by federal regulations? Actually, no – we are not. In the US, as in many countries, the government regulates the concentration of arsenic in drinking water, but does not regulate the concentration of arsenic in any other drink or food. We have a mercury-in-food regulation; why don’t we have an arsenic-in-food regulation?</p>
<p>One important difference is that all of the compounds of mercury we find in food are equally toxic. This is not the case for arsenic. Although we normally think of arsenic compounds as potentially harmful, most of the arsenic we eat is harmless. Seafood, which contains by far the highest concentrations of arsenic, delivers it as arsenobetaine, an organic chemical containing arsenic that is innocuous to us humans. </p>
<p>How then should arsenic in food be regulated? To do that well, we need to develop better ways to determine the amounts of arsenic and other chemicals in our foods.</p>
<h2>Focus on rice</h2>
<p>Scientists are still in the early days of collecting data on the arsenic content of food. So far, we think the only widely consumed foodstuffs with the potential for long-term health problems due to the arsenic content are rice and all rice-derived products, such as flour, cakes, crackers and infant formulas.</p>
<p>Chemical <a href="http://dx.doi.org/10.1155/2013/835371">analyses</a> show that regardless of the origin of the rice, four arsenic-containing compounds account for about 95% of the arsenic that is released from rice on cooking. Two of the compounds, together known as inorganic arsenic, are known human carcinogens, and two (monomethyl and dimethylated arsenic) are possibly carcinogenic to humans, according the <a href="http://monographs.iarc.fr/ENG/Monographs/vol100C/mono100C-6.pdf">International Agency for Research on Cancer</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/80531/original/image-20150505-948-12u8kd9.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">Rice fields can contain naturally occurring arsenic as well as compounds left over from spraying cotton.</span>
<span class="attribution"><span class="source">rice field via www.shutterstock com</span></span>
</figcaption>
</figure>
<p>There’s a wide range of arsenic concentrations in food. If an in-food safety limit were set based on a concentration level only, it would designate all food from the aquatic environment to be unfit for human consumption, even though there is no health risk. So an arsenic-in-food standard needs to specify which arsenic compounds are to be regulated.</p>
<p>Also, the health risks depend on the concentrations of the carcinogenic inorganic arsenic, the amount of rice consumed and how often rice is consumed. <a href="http://www.livescience.com/17293-arsenic-rice-worry.html">Some researchers</a> consider that to keep the risk of getting an arsenic-induced cancer to an acceptable level, the daily adult intake should not exceed a quarter cup of uncooked rice containing no more than 50 parts per billion (ppb), and that children should consume even less in proportion to their body weight. </p>
<p>The results for the analysis of a large number of rice and rice products presented by both <a href="http://www.consumerreports.org/cro/magazine/2012/11/arsenic-in-your-food/index.htm">Consumer Reports</a> and the <a href="http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm319948.htm">US Food and Drug Administration</a> show almost all rice tested contained concentrations in excess – sometimes well in excess – of this 50 ppb limit. Brown rice has, in general, concentrations of arsenic higher than those in white rice.</p>
<h2>Recent science</h2>
<p>We do not know how long we have been exposed. Only relatively recently have advances in chemical measurement technology made it possible to detect arsenic compounds at relevant concentrations in foodstuffs. </p>
<p>The first results for the measurement of arsenic in rice were made in <a href="http://www.springer.com/us/book/9789400729469">1998</a>. The global extent of the contamination was not apparent until 2005, when it was realized that some of the highest concentrations of both inorganic and methylated arsenic compounds are found in rice grown in the US. Results so far show that all rice, regardless of variety and origin, contains easily measurable concentrations of arsenic compounds. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/80532/original/image-20150505-946-7z16fl.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">Certain groups are at more risk than others, depending on diet.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/pgoyette/257882137">Paul Goyette/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Why is there arsenic in rice? Rice is often grown in fields formerly used for cotton, whose production involved spraying with cacodylic acid (the dimethyl arsenic compound) to kill boll weevil pests, and then with arsenic acid to kill and desiccate the plant prior to mechanical harvesting. Rice also assimilates arsenic to a greater extent than other crops, such as <a href="http://pubs.acs.org/doi/abs/10.1021/es070627i">wheat and barley</a>.</p>
<p>Many of the arsenic-containing compounds that we eat and drink also come from processes involving naturally occurring arsenic, which is widely distributed on the Earth’s crust. All lifeforms, ranging from bacteria to primates, are capable of transforming the inorganic arsenic compounds derived from the minerals that get into the food web into a series of organic compounds, rendering them less toxic. </p>
<p>Since 2012, advocacy group <a href="https://consumersunion.org/news/fda-arsenic-in-rice-findings-underscore-concerns-about-long-term-safety/">Consumers Union</a> has been calling for an arsenic-in-food standard and the implementation of arsenic reduction strategies, such as phasing out the use of arsenic-containing pesticides. However, the FDA is <a href="http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm280202.htm">working on</a> a study of the long-term risks and will not consider taking any action until this is complete.</p>
<p>Those of us who do not eat more than the amounts recommended by <a href="http://www.consumerreports.org/cro/magazine/2015/01/how-much-arsenic-is-in-your-rice/index.htm">Consumer Reports</a> can probably afford to wait. But some groups within the population, whose diet consists of largely of rice, such as sufferers from celiac disease, infants, and Asian Americans, should be hoping for action sooner rather than later. Asian Americans are the only US racial/ethnic population for whom cancer is the leading cause of <a href="http://www.aancart.org/cancer-research/publications/asian-american-cancer-health-disparities">death</a> and a diet heavy on rice could contribute to this. </p>
<h2>Better methods needed</h2>
<p>Not all scientists agree on how to assess the health risks of consuming inorganic and methylated arsenic compounds. But no matter what the basis, at the very least, a meaningful arsenic-in-rice regulation has to be supported by reliable information on the inorganic arsenic concentration. Unfortunately, the chemical measurement community is making slow progress towards this capability. </p>
<p>A recent round-robin <a href="https://ec.europa.eu/jrc/sites/default/files/eur24314en.pdf">proficiency test</a>, in which almost 100 expert laboratories spread across 35 countries participated, involved the determination of the total arsenic and the inorganic arsenic in a carefully prepared rice flour reference material. </p>
<p>Depending on how stringent the evaluation criteria applied were, between 23% and 41% of the participants did not get a satisfactory result for the determination of total arsenic, and between 25% and 43% did not get a satisfactory result for the determination of inorganic arsenic. Furthermore, only a third of the participants actually submitted a result for the inorganic arsenic content, which probably means they were unable to determine the concentration of the most-harmful form.</p>
<p>We know enough to be concerned and consumers should be demanding more information. Incentives are needed not only to get rice suppliers to implement arsenic-reduction strategies but also to get analytical chemists to collaborate on the development of reliable methods. </p>
<p>A hard-to-meet inorganic arsenic-in-rice standard of less than 100 parts per billion would be a good start. In the meantime, choose white rice (basmati or sushi), rinse it in cold water, and cook it in excess water – arsenic-free, of course.</p><img src="https://counter.theconversation.com/content/40732/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julian Tyson receives funding from the National Science Foundation and the American Chemical Society. He is affiliated with the American Association for the Advancement of Science..</span></em></p>
Tests have shown that arsenic in rice often exceeds recommended daily levels, yet there are no in-food arsenic safety standards. Why not?
Julian Tyson, Professor of Analytical Chemistry, UMass Amherst
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/33691
2014-11-03T05:58:58Z
2014-11-03T05:58:58Z
High levels of cancer-causing arsenic in rice – so why isn’t it regulated in our food?
<figure><img src="https://images.theconversation.com/files/63397/original/bbc4yd99-1414757207.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Puffed with a bit of poison.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-1652009/stock-photo-a-hand-holding-a-rice-cake.html?src=iWxoqYIT_lV9pTMAWvg0Yw-5-5">Rice cake by Shutterstock</a></span></figcaption></figure><p>There are two sides to rice: the grain that feeds half the world – and the primary carcinogenic source of inorganic arsenic in our diet.</p>
<p><a href="http://www.who.int/mediacentre/factsheets/fs372/en/">Arsenic</a> is a natural occurring element that is ubiquitous in the environment. It is present primarily as inorganic arsenic, which is highly toxic. </p>
<p>What sets rice apart is that it is the only major crop that is grown under flooded conditions. It is this flooding that releases inorganic arsenic, normally locked up in soil minerals, which makes it available for the plant to uptake. Rice has, typically, ten times more inorganic arsenic than other foods and, as the <a href="http://www.efsa.europa.eu/en/efsajournal/doc/1351.pdf">European Food Standards Authority have reported</a>, people who eat a lot of rice are exposed to worrying concentrations. Chronic exposure can cause <a href="http://www.fao.org/news/story/en/item/238558/icode/">a range of health problems</a> including developmental problems, heart disease, diabetes and nervous system damage. However, most worrying are lung and bladder cancers.</p>
<h2>Children of most concern</h2>
<p>The first food that most people eat is rice porridge, thought suitable for weaning as rice is low in allergens, has good textural properties and tastes bland. As babies are rapidly growing they are at a sensitive stage of development and are known to be <a href="http://www.efsa.europa.eu/en/efsajournal/doc/1351.pdf">more susceptible to inorganic arsenic</a> than adults. </p>
<p>Babies and young children under five also eat around three times more food on a body weight basis than adults, which means that, relatively, they have three times greater exposures to inorganic arsenic from the same food item. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1134&fit=crop&dpr=1 754w, https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1134&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/63401/original/jhfxvf37-1414757636.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1134&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Babies more exposed.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-45034351/stock-photo-baby-boy-with-ricecake-at-mouth.html?src=u5hqqNMFQ9co3cb7PbSQ3g-1-16">Rice biscuit by Shutterstock.</a></span>
</figcaption>
</figure>
<p>The rice product market for young children, which includes biscuit crackers and cereals is booming. If the child is gluten intolerant then rice breads and rice milks can be added to this list. Gluten intolerant adults are also high rice consumers, as are those people of South-East Asian origin. </p>
<p>Rice milk is so high in inorganic arsenic that the UK Food Standards Agency <a href="http://webarchive.nationalarchives.gov.uk/20120206100416/http://food.gov.uk/news/newsarchive/2009/may/arsenicinriceresearch">issued the advice</a> that children under the age of four-and-a-half should not drink rice milk. Despite this, you would be hard-pressed to locate this advice on product packing or displays.</p>
<h2>Where are the regulations?</h2>
<p>While there is tight regulation around inorganic arsenic in our water supplies in Europe but none for food, yet in Europe only 5% of our inorganic arsenic comes from water <a href="http://www.efsa.europa.eu/en/efsajournal/doc/1351.pdf">and 95% from food</a>. Bottled water in the EU is around 50 times lower in inorganic arsenic water concentrations than rice. Therefore, you would need to drink five litres of water to get the equivalent arsenic dose of eating a small 100g (dry weight packet) portion of rice. The failure to regulate rice in food is unsustainable and needs to be rectified.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=560&fit=crop&dpr=1 600w, https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=560&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=560&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=704&fit=crop&dpr=1 754w, https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=704&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/63402/original/548q2dr7-1414757835.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=704&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Milling means less in white rice.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Rice#mediaviewer/File:Rice_p1160004.jpg">Takeaway</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The World Health Organisation and the Food and Agriculture Organisation of the UN <a href="http://www.fao.org/news/story/en/item/238558/icode/">have just announced guidelines</a> for inorganic arsenic in rice: 200 parts per billion for white rice and 400 parts per billion (ppb) for brown rice. Brown rice is higher in inorganic arsenic than white as arsenic is concentrated in the bran that is removed by milling to produce white rice. </p>
<p>The aim of these limits is to ensure that the bulk of the global rice supply falls below these thresholds rather than directly focusing on the risk inorganic arsenic poses to humans – the particular dangers for children for example. Without doing this, the WHO thresholds are basically meaningless. They certainly do not protect those at greatest risk such as children and the high rice consuming countries of south-east Asia. </p>
<p>Further pronouncements by the European Union and the US Food and Drug Administration are imminent. Let us hope they take a more enlightened view than the WHO and set standards based on protecting human health. It is only when appropriate standards are set that the rice industry can proactively develop plans to remove arsenic from rice to meet those standards.</p>
<p>Standards need to be set to protect those most at risk and 50 ppb for children and 100 ppb for all rice products would be achievable with concerted effort of regulators and industry, though – as every dose of inorganic arsenic carries a risk – the lower the better.</p>
<h2>What can be done now?</h2>
<p>There are a lot of practical solutions to remove inorganic arsenic from rice; from agricultural management and cultivar selection and breeding. Sourcing rice from regions with lower grain inorganic arsenic concentrations – for example, basmati rice is two to three-fold lower in inorganic arsenic than rice <a href="http://www.ferm-eu.org/downloads/FERM_CAP_2020_and_beyond.pdf">from the European Union</a> or from the US. Cooking rice in a large excess of water also helps to remove inorganic arsenic.</p>
<p>Changing dietary practice and food consumer advice to reduce rice in diets is also an option. There are a range of gluten-free alternatives to rice, so rethinking baby foods is an obvious way to proceed. Top of this list of rice alternatives for baby foods and for breakfast cereals, biscuits and snack bars marketed at young children is oats, which have a range of <a href="https://theconversation.com/health-check-five-must-have-foods-for-your-shopping-trolley-25265">other health-giving properties</a>.</p><img src="https://counter.theconversation.com/content/33691/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andy Meharg 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>
There are two sides to rice: the grain that feeds half the world – and the primary carcinogenic source of inorganic arsenic in our diet. Arsenic is a natural occurring element that is ubiquitous in the…
Andy Meharg, Professor of Plant and Soil Sciences, Queen's University Belfast
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/25999
2014-05-01T03:01:35Z
2014-05-01T03:01:35Z
Reducing the harms of toxic air in mining and smelting communities
<figure><img src="https://images.theconversation.com/files/47467/original/3nmwnxwf-1398904591.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C2900%2C1727&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mount Isa exceeded the national one-hour standard for sulfur dioxide emissions 49 times in 2012.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-105679361/stock-photo-smoking-chimney-smelter-against-of-the-blue-sky.html?src=AbSTRbHlZG-p1dQnbUo3oQ-1-44">Zurbagan/Shutterstock</a></span></figcaption></figure><p>Children in the mining towns of Mount Isa in Queensland and Port Pirie in South Australia are exposed to harmful levels of pollutants that increase their risk of learning and developmental disorders, and a number of serious illnesses. </p>
<p>A study we published today in the journal <a href="http://www.sciencedirect.com/science/article/pii/S1875963714000226">Aeolian Research</a> shows mines and smelters in these two towns have avoided any serious scrutiny over their atmospheric emissions of <a href="http://www.who.int/ipcs/features/arsenic.pdf">arsenic</a>, <a href="http://www.who.int/ipcs/features/cadmium.pdf">cadmium</a> (a heavy metal used in the manufacture of batteries), and <a href="http://www.foodauthority.nsw.gov.au/industry/food-business-issues/sulphur-dioxide/#.U2BREK2Sy9g">sulfur dioxide</a>. </p>
<p>Along with lead, these toxic substances are emitted at much higher levels than anywhere else in Australia. Port Pirie <a href="http://www.sciencedirect.com/science/article/pii/S1875963714000226">exceeded</a> the national one-hour standard for sulfur dioxide emissions 50 times in 2012. And recent 24-hour levels for lead, arsenic and cadmium were 45-times above recommended annual air quality levels for lead, 42-times above recommended levels for arsenic and 36-times above for cadmium. </p>
<p>Mount Isa also <a href="http://www.sciencedirect.com/science/article/pii/S1875963714000226">exceeded</a> the national one-hour standard for sulfur dioxide emissions 49 times in 2012. And recent 24-hour maximums were 25-times above recommended annual levels for lead, 495-times higher for arsenic and 36-times higher for cadmium.</p>
<p>The licencing, regulation and reporting of toxic air pollutants and related health effects in Mount Isa and Port Pirie is inconsistent, incomplete and misleading. It’s time for effective regulation to protect the health of local residents.</p>
<h2>Health harms</h2>
<p>So, what impact are these emissions having on the local communities?</p>
<p><strong>Arsenic</strong></p>
<p>Arsenic emissions from smelters are highly toxic; there are <a href="http://www.euro.who.int/en/health-topics/environment-and-health/air-quality/publications/pre2009/who-air-quality-guidelines-for-europe,-2nd-edition,-2000-cd-rom-version">no safe levels</a> of exposure. Although the effects of arsenic can take years to emerge, exposure is associated with skin lesions, damage to the <a href="http://brainfoundation.org.au/medical-info/47-peripheral-neuropathy">peripheral nerves</a>, gastrointestinal symptoms, diabetes, kidney disease, heart disease and <a href="http://www.nature.com/jes/journal/v22/n3/full/jes201215a.html">cancer</a>. </p>
<p>A study of children living around a Mexican smelter also <a href="http://www.ncbi.nlm.nih.gov/pubmed/17805430">showed</a> arsenic exposure affected children’s cognitive development.</p>
<p><strong>Cadmium</strong></p>
<p>Cadmium emitted from the mining and smelting operations <a href="http://www.who.int/ipcs/features/cadmium.pdf">can have harmful effects on</a> the kidneys, the skeletal system and the respiratory system, and is a known cause of cancer. Even at low levels cadmium has also been <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346779/">associated</a> with learning difficulties in children.</p>
<p><strong>Sulfur dioxide</strong></p>
<p>Elevated sulfur dioxide emissions are associated with increased problematic respiratory symptoms, disease and mortality as well as hospital admissions for <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2679612/">asthma</a>. </p>
<p>The <a href="http://www.health.qld.gov.au/ph/documents/tphn/healthindicatorsmihsd.pdf">most recent data for Mount Isa</a> shows that between 2002 and 2006 there were significant disparities in asthma rates for Mount Isa compared to the rest of Queensland. Hospitalisation rates are significantly higher (80%) compared to the rest of Queensland, and asthma mortality rates were 322% higher than the rest of the state.</p>
<p>Hospital admissions for respiratory illness are <a href="http://www.publichealth.gov.au/data/social-healthatlas-of-south-australia_-2010.html">similarly high</a> in Port Pirie. In 2007-08 there were 3,774 admissions per 100,000 people, compared with 2,036 per 100,000 for the remainder of South Australia.</p>
<p><strong>Lead</strong></p>
<p>The effects of lead exposure are greatest in unborn children and those aged under five years. This age group is most susceptible because their growing nervous and skeletal systems require high levels of calcium.</p>
<p>Calcium is an essential element for the proper development and function of the brain. Because lead (Pb2+) <a href="http://www.ncbi.nlm.nih.gov/pubmed/11097627">mimics calcium</a> (Ca2+), children living in a lead-rich environment absorb larger amounts of lead in place of calcium. This can interfere with the critical development of a child’s nervous system. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/47468/original/c3s3hxbn-1398904911.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&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">Children in Mount Isa and Port Pirie face air pollution levels that would not be acceptable elsewhere in the country.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-12293236/stock-photo-little-boy-play-in-the-sand-box-with-color-toy-car.html?src=z_A4jNBYpyrOl_5YJpDraQ-1-108">Nadina/Shutterstock</a></span>
</figcaption>
</figure>
<p>Australian guidelines recommend Australian children have blood lead levels less than ten micrograms per decilitre (10 µg/dL), though this is currently being reviewed and <a href="https://theconversation.com/time-to-rethink-blood-lead-goals-to-reduce-risk-to-childrens-health-10493">should be lowered</a> to a minimum of five micrograms per decilitre, but preferably lower.</p>
<p>At Port Pirie in 2011, 24.2% of children under five years had blood lead values above ten micrograms per decilitre. The proportion was similar in 2012, at 24.9% and slightly lower in 2013, at 22.7% At Mount Isa, a <a href="http://www.health.qld.gov.au/ph/documents/tphn/mtisa_leadrpt.pdf">2008 study</a> of 400 children aged one to five years revealed 11.3% had a blood lead level above ten micrograms per decilitre. </p>
<p>A <a href="http://www.health.qld.gov.au/ph/documents/tphn/lead_report_2010.pdf">smaller survey</a> of 167 children in 2010 showed the impacted was lower, at 4.8%, but with another 4.2% recording a blood lead level of nine micrograms per decilitre.</p>
<h2>Misleading reporting</h2>
<p>Our study discovered two critical ways in which the public are misled about the nature and extent of pollution. </p>
<p>First, is the selection of more favourable figures for blood lead values reported in children. </p>
<p>At Port Pirie, it is common practice for the South Australian health department to use the data including maternal surrogate blood values: the mother’s blood lead values. These are used in the absence of values for a child under nine months months of age. While these may correlate to new born’s levels, they are not children’s results and, in any case, blood lead values rise rapidly after <a href="http://www.nature.com/jes/journal/v17/n3/abs/7500512a.html">around two months</a>. </p>
<p>In addition, unlike protocols used for <a href="http://www.wnswlhd.health.nsw.gov.au/UserFiles/files/FarWest/ANNUAL%20LEAD%20REPORT%202012%20Final.pdf">Broken Hill children’s blood lead assessments</a>, only the last blood lead measure on a child in any year is used, irrespective of whether there are higher values from earlier in the year.</p>
<p>Together, the data from 2006 to 2010 shows this downplays the percentage of children who actually present with a blood lead value over ten micrograms per decilitre by 5.8% and 13.6%. </p>
<p>Second, at Mount Isa, the Queensland government is failing to use Australian or Queensland <a href="http://www.qld.gov.au/environment/pollution/monitoring/air-monitoring/air-quality-index/">statutory air quality values</a> to calculate the local air quality index for lead and arsenic. The statutory values for lead and arsenic are based on yearly averages and are set a maximum of 0.5 and 0.006 micrograms per cubic metre of air, respectively.</p>
<p>However, the government online air quality system uses higher 24-hour concentration values for lead and arsenic of 2.0 and 0.3 micrograms per cubic metre of air, respectively, to present a more favourable picture of emissions. Indeed, in the explanation of the calculation of the air quality index the government maintains it uses the lower Australian or Queensland statutory values.</p>
<p>On a <a href="http://www.ehp.qld.gov.au/air/data/search.php?category_id=4&mode=measurement&day=21&month=12&year=2011&hour=07">sample day in December 2011</a>, for instance, the concentrations of lead-in-air of 0.784 micrograms per cubic metre of air were published as being “good”, while arsenic-in-air were recorded as “fair”, at a concentration 202 micrograms per cubic metre of air.</p>
<p>But <a href="http://www.qld.gov.au/environment/pollution/monitoring/air-monitoring/air-quality-index/">proper calculation</a> of the index values, show they would be both poor with an index of 156.8 and 3,366 for lead and arsenic. So this means the levels are 56.8 and 3,266 percentage points above the recommended pollution goal. </p>
<h2>Reducing the harm</h2>
<p>Eight years ago Mount Isa Mines promised the community a <a href="http://www.mountisamines.com.au/EN/community/Pages/LeadPathwaysStudy.aspx">Lead Pathways Study</a> that would include the most critical aspect – air quality data. They are still waiting. </p>
<p>In the meantime, we already have overwhelming evidence that the communities of <a href="http://www.sciencedirect.com/science/article/pii/S0883292710000740">Mount Isa</a> and <a href="http://www.sciencedirect.com/science/article/pii/S0269749113001875">Port Pirie</a> are being unfairly and unreasonably subject to air pollution levels that would not be acceptable elsewhere in the country. </p>
<p>To <a href="http://www.legislation.sa.gov.au/lz/c/a/environment%20protection%20act%201993.aspx">achieve the objectives</a> of the relevant state <a href="https://www.legislation.qld.gov.au/LEGISLTN/CURRENT/E/EnvProtA94.pdf">environment protection legislation</a> and not compromise ecological sustainability and the health of the local communities, we need more frequent sampling, higher standards and shorter averaging periods for air quality. </p>
<p>We also need enforceable legal mechanisms that enable the environmental protection agencies (EPAs) to not only regulate more effectively but to actually stop ongoing systematic pollution by forcing closure, even if only temporarily. </p>
<p>This must be accompanied by a willingness within the EPAs to take such action, independent of manipulation by government or industry, as appears to be the case at present.</p><img src="https://counter.theconversation.com/content/25999/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark P. Taylor is an elected committee member and member of the Technical Advisory Board for the Lead Group Inc. He receives no payment or other financial benefit for this work. The Lead Group Inc is a not-for-profit community organisation that develops and provides information and referrals on lead poisoning and lead contamination prevention and management. See: <a href="http://www.lead.org.au">http://www.lead.org.au</a>.</span></em></p><p class="fine-print"><em><span>Janae Csavina, Louise Kristensen, and Peter Davies 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>
Children in the mining towns of Mount Isa in Queensland and Port Pirie in South Australia are exposed to harmful levels of pollutants that increase their risk of learning and developmental disorders, and…
Mark Patrick Taylor, Professor of Environmental Science, Macquarie University
Janae Csavina, QA/QC Scientist, National Ecological Observatory Network; Department of Chemical and Environmental Engineering, University of Arizona
Louise Kristensen, PhD Candidate, Macquarie University
Peter Davies, Program Director Master of Environmental Planning, Macquarie University
Licensed as Creative Commons – attribution, no derivatives.