tag:theconversation.com,2011:/id/topics/heavy-metals-19823/articlesHeavy metals – The Conversation2023-08-10T20:00:53Ztag:theconversation.com,2011:article/2104622023-08-10T20:00:53Z2023-08-10T20:00:53ZWhat’s in vapes? Toxins, heavy metals, maybe radioactive polonium<figure><img src="https://images.theconversation.com/files/541174/original/file-20230804-29-77kck2.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&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/young-girl-smokes-disposable-electronic-cigarette-1943062066">Shutterstock</a></span></figcaption></figure><p>If you asked me what’s in e-cigarettes, disposable vapes or e-liquids, my short answer would be “we don’t fully know”.</p>
<p>The huge and increasing range of products and flavours on the market, changes to ingredients when they are heated or interact with each other, and inadequate labelling make this a complicated question to answer.</p>
<p><a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev-anchem-061318-115329">Analytical chemistry</a>, including <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">my own team’s research</a>, gives some answers. But understanding the health impacts adds another level of complexity. E-cigarettes’ risk to health varies depending on <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.1c00070">many factors</a> including which device or flavours are used, and how people use them.</p>
<p>So vapers just don’t know what they’re inhaling and cannot be certain of the health impacts.</p>
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Read more:
<a href="https://theconversation.com/no-vapes-arent-95-less-harmful-than-cigarettes-heres-how-this-decade-old-myth-took-off-203039">No, vapes aren't 95% less harmful than cigarettes. Here's how this decade-old myth took off</a>
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<h2>What do we know?</h2>
<p>Despite these complexities, there are some consistencies between what different laboratories find.</p>
<p>Ingredients include nicotine, flavouring chemicals, and the liquids that carry them – primarily propylene glycol and glycerine.</p>
<p><a href="https://www.industrialchemicals.gov.au/sites/default/files/2020-08/Non-nicotine%20liquids%20for%20e-cigarette%20devices%20in%20Australia%20chemistry%20and%20health%20concerns%20%5BPDF%201.21%20MB%5D.pdf">Concerningly</a>, we also find volatile organic compounds, particulate matter and carcinogens (agents that can cause cancer), many of which we know are harmful. </p>
<p>Our <a href="https://www.mja.com.au/journal/2019/210/3/nicotine-and-other-potentially-harmful-compounds-nicotine-free-e-cigarette">previous</a> <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">research</a> also found 2-chlorophenol in about half of e-liquids users buy to top-up re-fillable e-cigarettes. This is one example of a chemical with no valid reason to be there. Globally, it’s <a href="https://pubchem.ncbi.nlm.nih.gov/compound/2-Chlorophenol#section=Hazard-Classes-and-Categories">classified</a> as “harmful if inhaled”. Its presence is likely due to contamination during manufacturing.</p>
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Read more:
<a href="https://theconversation.com/many-e-cigarette-vaping-liquids-contain-toxic-chemicals-new-australian-research-169615">Many e-cigarette vaping liquids contain toxic chemicals: new Australian research</a>
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<h2>How about polonium?</h2>
<p>One potential ingredient that has been in the news in recent weeks is radioactive polonium-210, the same substance used to <a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">assassinate</a> former Russian spy Alexander Litvinenko in 2006. The Queensland government is <a href="https://www.abc.net.au/news/2023-07-26/queensland-scientists-test-vapes-for-polonium-210/102564282">now testing</a> vapes for it.</p>
<p>Polonium-210 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9207432/">can be found</a> in traditional cigarettes and other tobacco products. That’s because tobacco plants <a href="https://www.science.org/doi/abs/10.1126/science.153.3738.880">absorb it</a> and other radioactive materials from the soil, air and high-phosphate fertiliser.</p>
<p>Whether polonium-210 is found in aerosols produced by e-cigarettes remains to be seen. Although it is feasible if the glycerine in e-liquids comes from plants and similar fertilisers are used to grow them.</p>
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Read more:
<a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">Litvinenko poisoning: polonium explained</a>
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<h2>It’s not just the ingredients</h2>
<p>Aside from their ingredients, the materials e-cigarette devices are made from can end up in our bodies.</p>
<p><a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP2175">Toxic metals</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP5686">related substances</a> such as arsenic, lead, chromium and nickel can be detected in both e-liquids and vapers’ urine, saliva and blood.</p>
<p>These substances can pose serious health risks (such as being carcinogenic). They can leach from several parts of an e-cigarette, including the heating coil, wires and soldered joints.</p>
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<a href="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful, disposable vapes on a blue background" src="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chemicals from the device itself can end up in our blood, urine and saliva.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-colorful-disposable-electronic-cigarettes-on-2065547126">Shutterstock</a></span>
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Read more:
<a href="https://theconversation.com/we-asked-over-700-teens-where-they-bought-their-vapes-heres-what-they-said-190669">We asked over 700 teens where they bought their vapes. Here's what they said</a>
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<h2>That’s not all</h2>
<p>The process of heating e-liquids to create an inhalable aerosol also changes their chemical make-up to produce <a href="https://pubs.acs.org/doi/10.1021/acs.chemrestox.9b00410">degradation</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">products</a>. </p>
<p>These include:</p>
<ul>
<li><p>formaldehyde (a substance used to embalm dead bodies)</p></li>
<li><p>acetaldehyde (a key substance that contributes to a hangover after drinking alcohol)</p></li>
<li><p>acrolein (used as a chemical weapon in the first world war and now used as a herbicide).</p></li>
</ul>
<p>These chemicals are <a href="https://www.mdpi.com/2305-6304/10/12/714">often detected</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129974">e-cigarette samples</a>. However due to different devices and how the samples are collected, the <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0249-x">levels measured</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">vary widely</a> between studies.</p>
<p>Often, the levels are very low, leading to proponents of vaping arguing e-cigarettes are far safer than tobacco smoking. </p>
<p>But this argument does not acknowledge that many e-cigarette users (particularly adolescents) <a href="https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-3-extent">were or are not cigarette smokers</a>, meaning a better comparison is between e-cigarette use and breathing “fresh” air. </p>
<p>An e-cigarette user is undoubtedly exposed to more toxins and harmful substances than a non-smoker. People who buy tobacco cigarettes are also confronted with a plethora of warnings about the hazards of smoking, while vapers generally are not.</p>
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Read more:
<a href="https://theconversation.com/sex-and-lies-are-used-to-sell-vapes-online-even-we-were-surprised-at-the-marketing-tactics-we-found-200446">Sex and lies are used to sell vapes online. Even we were surprised at the marketing tactics we found</a>
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<h2>How about labelling?</h2>
<p>This leads to another reason why it’s impossible to tell what is in vapes – the lack of information, including warnings, <a href="https://www.legislation.gov.au/Details/F2021L00595">on the label</a>.</p>
<p>Even if labels are present, they don’t always reflect what’s in the product. Nicotine concentration of e-liquids is often quite different to what is on the label, and “nicotine-free” e-liquids often <a href="https://journal.chestnet.org/article/S0012-3692(20)30134-3/fulltext">contain nicotine</a>.</p>
<p>Products are also labelled with generic flavour names such as “berry” or “tobacco”. But there is no way for a user to know what chemicals have been added to make those “berry” or “tobacco” flavours or the changes in these chemicals that may occur with heating and/or interacting with other ingredients and the device components. “Berry” <a href="https://tobaccocontrol.bmj.com/content/30/2/185">flavour</a> alone could be made from <a href="https://tobaccocontrol.bmj.com/content/tobaccocontrol/suppl/2020/02/10/tobaccocontrol-2019-055447.DC1/tobaccocontrol-2019-055447supp001_data_supplement.pdf">more than 35</a> different chemicals. </p>
<p>Flavouring chemicals may be “food grade” or classified as safe-to-eat. However mixing them into e-liquids, heating and inhaling them is a very different type of exposure, compared to eating them.</p>
<p>One example is benzaldehyde (an almond flavouring). When this is inhaled, it <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.9b00171">impairs</a> the <a href="https://www.sciencedirect.com/science/article/pii/S2214750023000380">immune function</a> of lung cells. This could potentially reduce a vaper’s ability to deal with other inhaled toxins, or respiratory infections. </p>
<p>Benzaldehyde is one of only <a href="https://www.legislation.gov.au/Details/F2021L00595">eight</a> banned e-liquid ingredients in Australia. The list is so short because we don’t have enough information on the health effects if inhaled of other flavouring chemicals, and their interactions with other e-liquid ingredients.</p>
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<h2>Where to next?</h2>
<p>For us to better assess the health risks of vapes, we need to learn more about:</p>
<ul>
<li><p>what happens when flavour chemicals are heated and inhaled</p></li>
<li><p>the interactions between different e-liquid ingredients</p></li>
<li><p>what other contaminants may be present in e-liquids</p></li>
<li><p>new, potentially harmful, substances in e-cigarettes.</p></li>
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<p>Finally, we need to know more about how people use e-cigarettes so we can better understand and quantify the health risks in the real world.</p><img src="https://counter.theconversation.com/content/210462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Larcombe has previously received funding for e-cigarette research from the National Health and Medical Research Council, Lung Foundation Australia, Minderoo Foundation, Health Department of Western Australia and Asthma Foundation of Western Australia. The funders played no role in the conduct of the research. He is also a member of the Australian Council on Smoking and Health (ACOSH).</span></em></p>It’s not just the ingredients we should be concerned about. The devices themselves release chemicals that end up in our blood and urine.Alexander Larcombe, Associate Professor and Head of Respiratory Environmental Health, Telethon Kids InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081112023-06-22T03:40:03Z2023-06-22T03:40:03ZHuge Cadia gold mine ordered to reduce polluting dust. Is it safe to live near a mine like this?<p>For the past 15 months, I have been helping residents living near the massive Cadia gold and copper mine in NSW to verify their concerns about pollution from the mine. The findings of alarming levels of heavy metals in their water tanks, as well as in blood and hair samples, prompted the NSW Environmental Protection Agency to investigate. Yesterday it <a href="https://www.epa.nsw.gov.au/news/media-releases/2023/epamedia230621-epa-requires-immediate-action-by-newcrest-to-comply">ordered the mine</a> to stop releasing an “unacceptable level” of dust that carries these metals through the air.</p>
<p>The EPA is <a href="https://www.epa.nsw.gov.au/working-together/community-engagement/updates-on-issues/cadia-gold-mine">advising</a> that the water from tanks in the area is safe to drink. This advice is based on the results of NSW Health tests of residents’ kitchen tap water in March 2023. The EPA is also helping to organise water testing for locals, many of whom rely on rainwater tanks for their drinking water. </p>
<p>I remain unconvinced the water is always safe to drink. Metals accumulate in the bottom layers of tanks, so when water levels fall, people could be drinking water with a higher metal content.</p>
<p>These developments also do little to reassure residents who have similar concerns about other recently approved metal mines in NSW.</p>
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<h2>What forced the EPA to act?</h2>
<p>I first heard of complaints of dust blowing from the mine, particularly from its tailings disposal area, in 2021. Locals <a href="https://www.abc.net.au/news/2021-04-20/cadia-residents-exposed-to-tailings-dust/100078334">expressed concerns</a> about the impacts on their health of inhaling the dust. </p>
<p>Over the past year, many people in the area have sent me water samples from their home water tanks. These are fed by roof runoff, which they were concerned could carry metal-rich dust into the tanks. </p>
<p>I sent the water samples to a commercial testing laboratory. The results have been very confronting. Many samples failed to meet <a href="https://www.nhmrc.gov.au/about-us/publications/australian-drinking-water-guidelines">Australian Drinking Water Guidelines</a>. </p>
<p>This prompted a community group to run their own citizen science survey of local drinking water quality. They systematically collected water samples from the bottom of household rainwater tanks on dozens of properties surrounding the mine. They sent the samples to a commercial testing laboratory. </p>
<p>I reviewed the results of their study, conducted in February and March this year. Coupled with a previous study, we had results for 47 water samples, and 32 (68%) exceeded the drinking water guidelines for lead (less than 10 micrograms per litre). Alarmingly, 13 samples (27.6%) recorded concentrations of more than ten times (100µg/L of lead) the recommended limit. </p>
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<img alt="Two rainwater tanks outside a house" src="https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533342/original/file-20230622-27-yiknqj.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">
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<span class="caption">When rainwater tanks run low, residents are at higher risk of exposure to metals that build up at the bottom of their tanks.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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Read more:
<a href="https://theconversation.com/not-all-of-us-have-access-to-safe-drinking-water-this-clever-rainwater-collector-can-change-that-188800">Not all of us have access to safe drinking water. This clever rainwater collector can change that</a>
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<p>Many community members also <a href="https://www.theguardian.com/australia-news/2023/jun/02/water-heavy-metal-contamination-near-cadia-hill-nsw-goldmine">reported</a> elevated levels of metals in <a href="https://www.abc.net.au/news/2023-05-22/epa-probe-cadia-gold-mine-heavy-metal-contamination-claims/102374344">blood and hair samples</a>.</p>
<p>Lead is a major health issue in <a href="https://abcnews.go.com/US/lead-water-americas-water-dangerous-drink/story?id=98438736">water supplies across the United States</a>. It’s a neurotoxin that builds up in the body and can cause <a href="https://www.cdc.gov/nceh/lead/prevention/sources/water.htm#:%7E:text=The%20most%20common%20sources%20of,1986%20may%20also%20contain%20lead">lifelong brain impairment</a>.</p>
<p>Yet the community was struggling to be heard – by the EPA in particular. On May 12 this year, I was invited to meet with NSW EPA CEO Tony Chappel. I brought two members of the Cadia community. </p>
<p>They talked about their concerns about drinking water. They also broke the news about excessive metals in local residents’ blood results. That meeting changed everything. </p>
<p>In the following weeks the EPA has acted swiftly to stop this pollution and help the community. The agency is focusing on a major potential source of the contamination from the mine: dust. </p>
<p>The EPA has now <a href="https://www.epa.nsw.gov.au/-/media/epa/corporate-site/resources/community/letter-to-cadia-holdings-pty-limited-21-6-23.pdf">ordered the mine</a> to take all necessary steps to immediately stop releasing excessive amounts of dust, which may include <a href="https://www.epa.nsw.gov.au/news/media-releases/2023/epamedia230621-epa-requires-immediate-action-by-newcrest-to-comply">reducing production</a>. </p>
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Read more:
<a href="https://theconversation.com/children-continue-to-be-exposed-to-contaminated-air-in-port-pirie-113484">Children continue to be exposed to contaminated air in Port Pirie</a>
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<h2>Why is dust such a critical problem?</h2>
<p>The Cadia <a href="https://www.cadiavalley.com.au/newcrest/cvo/news">gold and copper mine</a> has been operating for more than 25 years. It includes an open-cut mine and more recently an underground mine, the <a href="https://www.mining-technology.com/projects/cadia/">largest in Australia</a>. It is the underground mining that now seems central to the contamination.</p>
<p>The EPA issued a “prevention notice” on May 29 this year. The agency <a href="https://www.epa.nsw.gov.au/-/media/epa/corporate-site/resources/community/letter-to-cadia-holdings-pty-limited-21-6-23.pdf">pointed to</a> a ventilation vent (vent rise 8) that was releasing more than seven times the permitted dust content. Also known as the “crusher vent”, it has caused other serious air quality concerns, with <a href="https://www.abc.net.au/news/2022-11-21/cadia-valley-operations-fails-air-quality-audit-expansion/101674962">emissions of cancer-causing crystalline silica</a> recorded at 18 times the legal limit. </p>
<p>In <a href="https://www.abc.net.au/news/2022-08-25/cadia-gold-mine-orange-fined-maximum-epa-penalty-dust-pollution/101370850">August 2022</a> and <a href="https://www.abc.net.au/news/2021-04-20/cadia-residents-exposed-to-tailings-dust/100078334">July 2020</a>, the EPA had fined the mine the maximum $15,000 for dust pollution and is clearly frustrated by its <a href="https://www.abc.net.au/news/2022-11-21/cadia-valley-operations-fails-air-quality-audit-expansion/101674962">unacceptable impacts</a>. It has just issued the mine with revised environmental regulations. </p>
<p>The EPA <a href="https://www.epa.nsw.gov.au/news/media-releases/2023/epamedia230621-epa-requires-immediate-action-by-newcrest-to-comply">press release</a> yesterday said: “Additional reports will also be required on lead dust fingerprinting research.” This “fingerprinting” <a href="https://pubmed.ncbi.nlm.nih.gov/20047782/">analysis</a> of lead helps trace its transport pathways and geological origins.</p>
<p>In a statement in response to the EPA’s latest action, the mine operator, Cadia Valley Operations, said: “We take our environmental obligations and the concerns raised by the EPA seriously and will take action to comply with the licence variation notice.”</p>
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Read more:
<a href="https://theconversation.com/mount-isa-contamination-within-guidelines-but-residents-told-to-clean-their-homes-72862">Mount Isa contamination 'within guidelines' but residents told to clean their homes</a>
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<h2>What does this mean for residents near other mines?</h2>
<p>This case might not be isolated. Gold and silver mining in NSW is booming. </p>
<p><a href="https://www.ipcn.nsw.gov.au/news/2023/03/mcphillamys-gold-mine">Approved in March</a>, McPhillamys gold mine near the town of Blayney is about 20 kilometres from Cadia mine. And the Bowdens silver mine near Mudgee was <a href="https://www.ipcn.nsw.gov.au/resources/pac/media/files/pac/projects/2022/12/bowdens-silver/determination/230403-bowdens-silver-project-ssd-5765-statement-of-reasons-for-decision.pdf">approved</a> the following month, despite many submissions expressing concern about the impacts of lead dust on human health.</p>
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Read more:
<a href="https://theconversation.com/gold-mining-is-one-of-the-worlds-most-destructive-and-unnecessary-industries-heres-how-to-end-it-197447">Gold mining is one of the world’s most destructive and unnecessary industries – here's how to end it</a>
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<p>Can people be safe and healthy living near a large metal mining operation? Based on Cadia, I’m not sure. </p>
<p>Mines and regulators might need to work more closely together with communities. The public needs to be able to make sure government agencies are doing their job and every mine operates in an environmentally clean and safe manner. The mining industry has to do better to earn the trust of the community and its “<a href="https://www.australianmining.com.au/miners-need-to-improve-social-license-to-operate-nsw-minerals-council/">social licence</a>” to operate.</p><img src="https://counter.theconversation.com/content/208111/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian A Wright has received funding from industry, as well as Commonwealth, NSW and local governments. He has assisted the Environmental Defenders Office in several matters involving pollution associated with mining activity. </span></em></p>The action by the Environment Protection Authority follows alarming results from testing of rainwater tanks and the blood and hair of residents living near to the mine.Ian A. Wright, Associate Professor in Environmental Science, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2006892023-06-05T12:09:06Z2023-06-05T12:09:06ZArsenic 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 UniversityDiana Azzam, Assistant Professor of Environmental Health Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2043792023-05-04T13:43:07Z2023-05-04T13:43:07ZCape Town’s caracals have metal pollutants in their blood – an environmental red flag<figure><img src="https://images.theconversation.com/files/522774/original/file-20230425-2394-iok407.jpg?ixlib=rb-1.1.0&rect=6%2C507%2C4019%2C2124&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A caracal monitored by the Urban Caracal Project, TMC33 Hermes, walks across a pipeline in Cape Town. </span> <span class="attribution"><span class="source">Kris Marx</span></span></figcaption></figure><p>South Africa is urbanising rapidly. By <a href="https://pmg.org.za/page/Urbanisation">2050</a>, eight in 10 people will live in urban areas, significantly increasing the demands on basic infrastructure development and associated services.</p>
<p>In the country’s Western Cape province, some 90% of the population is urbanised. Most of its residents live in the <a href="https://www.westerncape.gov.za/provincial-treasury/files/atoms/files/City%20of%20Cape%20Town%20SEP-LG%202022%20.pdf">Cape Metropolitan Area</a>. So it is truly remarkable that the city is still home to a population of between 60 and 100 wild <a href="http://www.urbancaracal.org/">caracals</a>.</p>
<p>Hikers on Table Mountain’s trails and greenbelts may have briefly spotted one of these elusive cats with their reddish-brown coat and tufted ears before they disappeared into the dense vegetation.</p>
<p>Having survived the <a href="https://www.academia.edu/1487856/Keeping_the_Enemy_at_Bay_The_Extermination_of_Wild_Carnivora_in_the_Cape_Colony_1889_1910">eradication</a> of larger carnivores like the Cape leopard and lion, this highly adaptable, medium-sized wild cat is now Cape Town’s apex wildlife predator.</p>
<p>The <a href="http://www.urbancaracal.org/">Urban Caracal Project</a>, a research and education initiative based at the University of Cape Town’s <a href="http://www.icwild.uct.ac.za">Institute for Wildlife and Communities in Africa</a>, is dedicated to studying Cape Town’s caracal population. It aims to better understand the effects of urbanisation on the city’s wildlife and to discover some of the secrets of how they are able to survive in this challenging landscape.</p>
<p>But surviving in a rapidly expanding city isn’t easy. Indeed, it can be <a href="https://theconversation.com/toxic-cities-urban-wildlife-affected-by-exposure-to-pollutants-127590">downright dangerous</a> thanks to, among other issues, the increasing presence of environmental pollutants.</p>
<p>As conservation biologists, we are interested in how caracals become exposed to the multitude of pollutants associated with city-living. To do this, <a href="https://www.sciencedirect.com/science/article/pii/S0269749123005870">we tested</a> the blood of caracals in Cape Town and found worryingly high numbers of different metal pollutants present. Exposure to these metals, including aluminium, arsenic, cadmium, copper, mercury and lead, most likely occurs via the prey species that caracals consume. </p>
<p>This raises important environmental concerns for all the city’s residents – both wildlife and human.</p>
<h2>Metal pollutants are a global biodiversity threat</h2>
<p><a href="https://pubs.acs.org/doi/10.1021/acs.est.1c04158">Chemical pollution</a> is a growing global concern. Cities and rapidly developing countries are disproportionately affected because they are characterised by high levels of both industrial and human activity. <a href="https://www.sciencedirect.com/science/article/pii/S1018364722000465">Metallic chemical elements</a> are some of the most toxic and well-studied of these environmental chemical pollutants.</p>
<p>Most metals occur naturally in the Earth’s crust. However, numerous human activities increase the quantity of, and rate at which, metals are released into the environment. Major sources of metal pollution include coal power plants, mines, agricultural activities, and waste disposal sites like landfills and illegal dumps. </p>
<p>The most dangerous of the metal pollutants are mercury, arsenic, and lead. These can all be extremely toxic to animals and humans, even in small amounts.</p>
<p>Both animals and humans are generally exposed to harmful metals through food and water. After entering lower down the food chain, metals accumulate over time in bodily fluids and tissues via a process called <a href="https://www.sciencedirect.com/topics/chemistry/bioaccumulation">bioaccumulation</a>.
Pollutants then tend to move up through the food chain, becoming more concentrated through the process of <a href="https://link.springer.com/article/10.1007/s40726-017-0061-9">biomagnification</a>.</p>
<p>Consequently, animals occupying higher positions across an ecosystem’s food web, especially top predators like caracals, are exposed to greater concentrations of pollutants than those lower down. Exposure to metal pollutants can reduce reproductive success. It also impacts the immune system, damages the nervous system, and increases the risk of cancer and cancer-related diseases. In acute cases it can lead to death.</p>
<h2>Detecting toxic metals in wildlife</h2>
<p>For <a href="https://www.sciencedirect.com/science/article/pii/S0269749123005870">our research</a>, individual caracals were caught using cage traps and then sedated. A veterinarian then took blood samples. Caracals killed in vehicle collisions, and <a href="http://www.urbancaracal.org/report-sightings-roadkill">reported</a> by the public to the project, were also opportunistically sampled. </p>
<p>Our blood analysis revealed that most metals detected were not present at toxic levels. However, the worrying exceptions were arsenic and chromium, both of which pose serious health risks. Hunting at the urban edge and in places with more human activity, such as near roads, vineyards and suburbs, exposes caracals to a greater number of metals and at higher levels than when hunting further away from these areas.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522947/original/file-20230426-186-uyicf4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=410&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Diagram showing potential pathways of metal pollutant exposure in Cape Town caracals. Hg = mercury, As = arsenic, Se = selenium, Pb = lead, Al = aluminium.</span>
<span class="attribution"><span class="source">Authors supplied</span></span>
</figcaption>
</figure>
<p>This is very concerning given that our research has also shown a similar trend for caracal exposure to other pollutant stressors, including groups of man-made chemicals, like <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969722006738">organochlorines</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969719306047">anticoagulant rodenticides</a> (rat poison), as well as novel <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-020-04075-5">pathogens</a>.</p>
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Read more:
<a href="https://theconversation.com/cape-towns-caracals-are-exposed-to-harmful-forever-chemicals-through-their-diet-186314">Cape Town's caracals are exposed to harmful 'forever chemicals' through their diet</a>
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<h2>Dietary contamination through waterbirds</h2>
<p>Our most interesting and unexpected discovery was that caracals hunting within or nearby coastal and wetland areas in Cape Town, where they enjoy a diet rich in aquatic-adapted birds, were more exposed to harmful metals like arsenic, mercury, and selenium than those on the urban edges. </p>
<p>This suggests that aquatic prey species – seabirds and waterbirds like Cape cormorants, gulls, Egyptian geese, and yellow billed ducks – are likely the main source of metal exposure in caracal.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=289&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=289&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=289&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=363&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=363&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522583/original/file-20230424-28-nqtw1e.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=363&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A caracal hunts cormorants in Cape Town.</span>
<span class="attribution"><span class="source">Anya Adendorff</span></span>
</figcaption>
</figure>
<p>Our findings highlight that Cape Town’s freshwater and marine systems are likely more polluted than expected. Aquatic environments generally act as long-term sinks which accumulate a range of pollutants. Coal combustion, emissions from domestic fuel burning, natural fires and untreated city wastewater are all likely sources of metal contamination. </p>
<p>This may have implications for the health of other mammalian and avian predators in our study area, as well as human health implications for local fishing communities and wider seafood consumers. </p>
<h2>Improving the city’s ecological health</h2>
<p>The City of Cape Town can do more to evaluate and mitigate this issue.</p>
<p>The first step is appropriate monitoring of the problem – identifying the sources and understanding the scale. Monitoring should be focused on the urban edge, waste management sites, water treatment plants, road run-off, and agricultural areas.</p>
<p>It is crucial to develop a robust local, provincial, and national pollutant monitoring programme using a variety of indicator species. Such species, including small and medium-sized carnivores, like caracals, together with aquatic animals, are especially sensitive to the effects of bioaccumulation. Monitoring populations and regularly testing for levels of pollutants in their tissues will provide a clearer understanding of Cape Town’s broader environmental health.</p>
<p>Other mitigation strategies include wetland and freshwater system clean-ups, implementing stricter regulations on fuel-burning emissions, improved treatment and disposal of city wastewater, and reduced use of agricultural pesticides. Taking these necessary steps will greatly improve both animal and human health.</p>
<p><em>Kim Helene Parker, a recent Masters graduate from the University of Cape Town, co-authored both this article and the research it is based on.</em></p><img src="https://counter.theconversation.com/content/204379/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>Caracals are most likely being exposed to metals like arsenic, lead and mercury through their diet.Gabriella Leighton, Post-Doctoral Fellow, Rhodes UniversityJacqueline Bishop, Senior Lecturer in Conservation Ecology & Genetics, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2028642023-04-29T18:47:55Z2023-04-29T18:47:55ZFur seals on a remote island chain are exposed to huge amounts of toxic heavy metals – yet somehow, they’re healthy<figure><img src="https://images.theconversation.com/files/522568/original/file-20230424-26-b71nkr.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C4608%2C3456&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Juan Fernández fur seals were once hunted for their semi-waterproof fur.</span> <span class="attribution"><span class="source">Constanza Toro Valdivieso</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Juan Fernández fur seals are so poorly understood that they were considered extinct for nearly a century before a remnant population which had managed to evade generations of hunters was rediscovered in the 1960s. </p>
<p>Their mysterious nature owes a lot to their seclusion on an archipelago of the same name 600km off the Chilean coast. These remote islands are situated in a protected national park – the last place you might expect to find animals exposed to high levels of pollution. But samples I collected and analysed with colleagues tell us something different.</p>
<p>Our <a href="https://doi.org/10.1098/rsos.221237">most recent study</a> analysed fur seal poo and found concentrations of cadmium and mercury that were among the highest reported for any mammal worldwide. This species is ingesting exceptionally high concentrations of these toxic heavy metals through its diet, but how they enter the food chain proved to be more complicated than we anticipated.</p>
<p>By studying these marine mammals, scientists can discover how polluted the wider environment is. Better yet, we may learn a trick or two from them on surviving amid pollution.</p>
<h2>Where are the heavy metals coming from?</h2>
<p>Some metals, such as zinc and iron, are essential micronutrients which we’re encouraged to include in our diet. This is not the case with mercury and cadmium. <a href="https://dictionary.apa.org/mad-hatters-disease">Mad Hatter’s disease</a> is a neurological disorder associated with mercury intoxication, while <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5734474/#:%7E:text=Itai%2Ditai%20disease%20is%20caused,associated%20with%20renal%20tubular%20dysfunction.">Itai-itai disease</a>, which translates from the Japanese as “it hurts it hurts”, is a condition causing severe bone pain and weakening resulting from chronic cadmium poisoning that affected people working in contaminated rice fields in Toyama prefecture, Japan. These heavy metals are highly toxic even in small amounts, and they have few known biological uses.</p>
<p>Heavy metals occur naturally in the Earth’s crust and are emitted by volcanic eruptions or as a result of rocks being worn down by the weather. They’re also produced during mining, waste incineration and steelmaking. With the Juan Fernández Islands being so far from any major industries, we were initially perplexed by the seemingly toxic diet of these fur seals.</p>
<figure class="align-center ">
<img alt="A person wearing a head scarf and holding a shovel operates a machine crushing ore." src="https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522612/original/file-20230424-26-dnh5mj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Miners use mercury to extract gold from its ore.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/chami-mauritania-january-20-2019-artisanal-2091743224">Senderistas/Shutterstock</a></span>
</figcaption>
</figure>
<p>But the archipelago is located on the edge of a rotating current known as the South Pacific subtropical gyre which has gathered a <a href="https://doi.org/10.1016/j.marpolbul.2018.09.031">colossal</a> amount of ocean plastic. It is estimated that the plastic patch is <a href="https://www.snexplores.org/article/expedition-finds-south-pacific-plastic-patch-bigger-india">bigger than India</a>.</p>
<p>Unfortunately, Juan Fernández fur seal mothers must travel huge distances through this plastic cloud to hunt the nutrient-rich prey they need to carry on their pregnancies and make enough fatty milk for their pups. <a href="https://doi.org/10.1016/j.envint.2019.104937">Evidence shows</a> plastic debris can absorb toxins, including cadmium. So were the fur seals accidentally ingesting plastic or eating animals that had? The answer was more complicated.</p>
<p>Phytoplankton, or algae, are microscopic organisms similar to plants on land in that they contain chlorophyll and synthesise food from sunlight. Algae use micronutrients such as zinc to carry out their metabolism, but some parts of the ocean, including gyres, tend to have low concentrations. <a href="https://doi.org/10.1016/j.epsl.2019.02.031">Studies</a> have shown that phytoplankton in these regions have evolved to use cadmium instead: the only known biological process in which cadmium is useful.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four world maps showing where different sizes of plastic are accumulating in the ocean." src="https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=344&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=344&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=344&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=432&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=432&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522614/original/file-20230424-24-k614lx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=432&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 South Pacific gyre is a global hotspot for tiny plastic fragments.</span>
<span class="attribution"><a class="source" href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111913">Eriksen et al. (2014)/PLOS One</a></span>
</figcaption>
</figure>
<p>Tiny, microscopic animals called zooplankton eat the cadmium-contaminated algae which are then eaten by fish and larger animals, which eventually end up in the bellies of octopus and squid, which are among the fur seal’s favourite food. These molluscs can accumulate large quantities of heavy metals in their kidneys and, especially, in an organ known as the hepatopancreas. Unlike humans, who largely only eat the tentacles, fur seals consume the whole prey, including the heavy metal-rich organs. So it may be that an evolutionary adaptation by phytoplankton has increased the risk of cadmium exposure in animals higher up the food chain.</p>
<h2>A new mystery</h2>
<p>Since cadmium severely damages the skeletons of mammals including humans, we wanted to see, after finding such vast quantities of cadmium in fur seal poo, if this heavy metal was being absorbed into their bones. </p>
<p>As expected, Juan Fernández fur seal skeletons were loaded with cadmium. But, to our surprise, we could not find any other mineral changes which would be expected in an animal suffering from cadmium poisoning. This suggests this species has somehow adapted to withstand the toxic heavy metal.</p>
<p>If that is the case, it may indicate that Juan Fernández fur seals have been exposed to natural sources of cadmium for thousands of years. To understand how, we must find a way to differentiate natural from man-made sources.</p>
<p>The reward for doing so may be great. There is sure to be much to learn from the resilience of this enigmatic species, which overcame extinction and still manages to thrive in a world where pollution has flooded even the most remote corners.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/202864/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Constanza Toro Valdivieso is affiliated with Fundación Endémica, Chile. </span></em></p>The mystery surrounding a forgotten marine mammal, a remote archipelago and man-made pollution.Constanza Toro Valdivieso, Postdoctoral Researcher in Molecular Biology, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1968592022-12-21T13:40:49Z2022-12-21T13:40:49ZUnusual, long-lasting gamma-ray burst challenges theories about these powerful cosmic explosions that make gold, uranium and other heavy metals<figure><img src="https://images.theconversation.com/files/502241/original/file-20221220-20-5eta2v.jpeg?ixlib=rb-1.1.0&rect=70%2C601%2C2172%2C1591&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When two neutron stars merge and create a black hole, they produce a powerful blast of gamma rays.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/14255"> A. Simonnet (Sonoma State Univ.) and NASA’s Goddard Space Flight Center</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em> </p>
<h2>The big idea</h2>
<p>A bright flash of gamma rays from the constellation Boötes that lasted nearly one minute came from a kilonova, as we described in <a href="https://doi.org/10.1038/s41586-022-05327-3">a new paper</a>. This finding challenges what astronomers know about some of the most powerful events in the universe.</p>
<p>The unusual cosmic explosion was detected by the <a href="https://www.nasa.gov/mission_pages/swift/main">Neil Gehrels Swift</a> observatory on Dec. 11, 2021, as the satellite orbited Earth. When astronomers pointed other telescopes at the part of the sky where this large blast of gamma rays – named GRB211211A – came from, they saw a glow of visible and infrared light known as a <a href="https://theconversation.com/we-beat-a-cyber-attack-to-see-the-kilonova-glow-from-a-collapsing-pair-of-neutron-stars-85660">kilonova</a>. The particular wavelengths of light coming from this explosion allowed our team to identify the source of the unusual gamma-ray burst as two neutron stars colliding and merging together.</p>
<p>Gamma rays are the most energetic form of electromagnetic radiation. In just a few seconds, a gamma-ray burst blasts out the same amount of energy that the Sun will radiate throughout <a href="https://www.scientificamerican.com/article/record-breaking-gamma-rays-reveal-secrets-of-the-universes-most-powerful-explosions/">its entire life</a>. Gamma-ray bursts are the <a href="https://theconversation.com/flash-aah-aah-could-a-gamma-ray-burst-eradicate-all-life-on-earth-5291">most powerful events in the universe</a>, and astronomers think only two cosmic scenarios can produce gamma-ray bursts.</p>
<p>The most common sources are the deaths of stars 30 to 50 times more massive than the Sun. The catastrophic destruction of one these large stars is called a <a href="https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-a-supernova.html">supernova</a>. When they explode, the stars create black holes that consume the leftover debris. These black holes emit a jet of matter and electromagnetic radiation that moves at close to the speed of light. In moments after the black hole starts emitting this high-energy stream of matter and radiation, the jet produces a burst of gamma rays that can last for minutes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of galaxies and stars in the sky with a graph showing brightness and duration." src="https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=624&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=624&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=624&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=785&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=785&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502215/original/file-20221220-24-6x1y81.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=785&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 unusual gamma-ray burst originated from the small red dot within the circle in this image. The graph shows how bright and long-lasting the burst was.</span>
<span class="attribution"><span class="source">International Gemini Observatory/NOIRLab/NSF/AURA/M. Zamani/NASA/ESA/Eleonora Troja</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Kilonovae are the second type of events associated with gamma-ray bursts. Kilonovae occur when a neutron star merges with another neutron star or is consumed by a black hole. Neutron stars <a href="https://theconversation.com/explainer-what-is-a-neutron-star-29341">are rather small stars</a> – about 1.4 to 2 times the mass of the Sun, though only dozens of miles across.</p>
<p>When two of these tiny, dense stars merge to produce a black hole, they leave very little material behind. Compared with the long-lasting feast a black hole gets after a supernova, kilonovae leave a black hole with little more than a snack that results in a gamma-ray burst that lasts only a second or <a href="https://doi.org/10.1088/0004-637X/764/2/179">two at most</a>.</p>
<p>For over 20 years, astronomers thought that kilonovae accompanied short gamma-ray bursts and supernovae accompanied long ones. So when our team started looking at the wealth of data and images collected on the minute-long burst in December 2021, we expected to see a supernova. Much to our surprise, we found a kilonova.</p>
<h2>Why it matters</h2>
<p>Kilonovae are cosmic factories that <a href="https://theconversation.com/piercing-the-mystery-of-the-cosmic-origins-of-gold-88880">create heavy metals</a>, including gold, platinum, iodine and uranium. Because they enrich the chemical composition of the universe, kilonovae are critical to providing the basic ingredients for the formation of planets and life.</p>
<p>GRB211211A’s long duration <a href="https://doi.org/10.1038/d41586-022-04165-7">contradicts existing theories</a> of how gamma-ray bursts relate to supernovae and kilonovae. This finding shows that there is still a lot astronomers like us don’t understand about these powerful and important processes and suggests that there may be other ways the universe can produce heavy metals.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FQLZPm34Chg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kilonovae are responsible for producing heavy metals – like gold, uranium and iodine – that are important for many processes in the universe.</span></figcaption>
</figure>
<h2>What still isn’t known</h2>
<p>The initial images and data gathered on this interesting event look like a kilonova produced from the collision of two neutron stars. But the long-lasting burst of gamma rays throws doubt on what exactly happened. It is possible that one of the players was a rare neutron star with an <a href="https://apod.nasa.gov/apod/ap980527.html">incredibly powerful magnetic field</a> – called a magnetar. The burst could also have been the result of a neutron star being <a href="https://theconversation.com/what-happens-when-black-holes-collide-with-the-most-dense-stars-in-the-universe-162526">torn apart by its companion black hole</a>. Or astronomers could have just witnessed a <a href="https://doi.org/10.1038/s41586-022-05403-8">new, previously unknown type of stellar crash</a>. </p>
<h2>What’s next</h2>
<p>The few exotic stellar encounters that produce gamma-ray bursts can look very similar to one another across the electromagnetic spectrum. However, the unique gravitational wave signatures they produce could be the key to solving the enigma. The gravitational wave detectors <a href="https://www.ligo.org/">LIGO</a>, <a href="https://www.virgo-gw.eu/">Virgo</a> and <a href="https://gwcenter.icrr.u-tokyo.ac.jp/en/">KAGRA</a> did not see GRB211211A, as they were all offline for improvements. If they can catch a long-duration gamma-ray burst after they begin operating again in <a href="https://observing.docs.ligo.org/plan/">2023</a>, the <a href="https://doi.org/10.1038/s42254-019-0101-z">combination of gravitational wave and electromagnetic data</a> may solve the mystery of this newly discovered event.</p><img src="https://counter.theconversation.com/content/196859/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eleonora Troja receives funding from the European Research Council under the European Union's Horizon 2020 research and innovation programme. </span></em></p><p class="fine-print"><em><span>Simone Dichiara 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>Gamma-ray bursts occur when a massive star explodes or when two neutron stars merge. A newly discovered burst has puzzled astronomers, as it lasted much longer than astronomers would have expected.Eleonora Troja, Associate Professor of Astrophysics, University of Rome Tor VergataSimone Dichiara, Assistant Research Professor of Astrophysics, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1911522022-09-27T13:11:58Z2022-09-27T13:11:58ZNigeria’s sacred Osun River supports millions of people - but pollution is making it unsafe<figure><img src="https://images.theconversation.com/files/486262/original/file-20220923-9077-t1qt1j.jpg?ixlib=rb-1.1.0&rect=16%2C5%2C3578%2C2382&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Osun River has become turbid and unsafe for consumption - threatening its cultural and biodiversity significance. Photo by: Stefan Heunis/AFP via Getty Images.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-throws-a-sacrificial-chicken-into-the-sacred-river-news-photo/1018606984?adppopup=true">from www,gettyimages.com</a></span></figcaption></figure><p><em>Pollution has become a worrying threat to Nigeria’s Osun River. The river supports millions of people who rely on the water for agriculture as well as industries. It is also an integral part of Nigeria’s treasured Osun-Osogbo sacred grove, a UNESCO world heritage site. Emmanuel O. Akindele unpacks what’s causing the pollution, what harm it’s causing and what must change to preserve the river’s biodiversity.</em> </p>
<h2>How important is the Osun River to Nigeria?</h2>
<p>The Osun River is one of the major rivers in southern Nigeria, <a href="https://link.springer.com/article/10.1007/s11356-020-08763-8">draining into the Gulf of Guinea</a>. The river takes its source from Ekiti State. But it’s culturally linked to the ancient city of <a href="https://core.ac.uk/download/pdf/236410037.pdf">Osogbo</a>. A stretch of the river that flows by a sacred grove in the ancient town of Osogbo has been designated a <a href="https://whc.unesco.org/en/list/1118/">UNESCO World Heritage Site</a> due to its <a href="https://whc.unesco.org/en/list/1118">cultural</a> significance. It is one of two such designated sites in <a href="https://whc.unesco.org/en/statesparties/ng">Nigeria</a>. </p>
<p>The river provides a wide range of cultural ecosystem services such as <a href="https://afribary.com/works/assessment-of-the-ecotourism-potentials-of-osun-osogbo-world-heritage-site-osun-state-nigeria">natural scenes</a> for eco-tourists and the site for filming Nollywood movies. A large number of foreign tourists <a href="https://www.academia.edu/52361771/HARNESSING_CULTURAL_HERITAGE_FOR_TOURISM_DEVELOPMENT_IN_NIGERIA_A_STUDY_OF_THE_OSUN_OSOGBO_SACRED_GROVE_AND_FESTIVAL">visit</a> the river each year. The visits are either to pay homage to the river goddess (Osun) or to join others in celebrating the <a href="https://www.vanguardngr.com/2022/08/2022-osun-festival-begins-with-spiritual-cleansing-of-roads/">annual Osun festival</a>. </p>
<p>The river also has enormous environmental value given its rich <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aje.12482">biodiversity</a>. It supports <a href="https://www.tandfonline.com/doi/abs/10.1080/21658005.2017.1357290?journalCode=tzec20">plankton</a>, <a href="https://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77442007000200034">snakes</a> and <a href="https://www.frim.gov.my/v1/JTFSOnline/jtfs/v26n1/5-15.pdf">endangered plants</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A flowing river bordered by dense forest." src="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486269/original/file-20220923-2090-r25747.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Osun River is one of the last remnants of primary high forest in southern Nigeria - UNESCO World Heritage Site. But pollution is threatening the river.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/osun-river-osun-osogbo-sacred-grove-osogbo-osun-royalty-free-image/1141985549?adppopup=true">from www.gettyimages.com</a></span>
</figcaption>
</figure>
<p>Along its whole course, the Osun River also plays a <a href="https://www.tandfonline.com/doi/pdf/10.1080/16583655.2019.1567899">critical part</a> in supporting the livelihoods of people. In many areas of Osogbo and Osun State, it provides irrigation for nearby farmlands. A significant number of abattoirs are also situated close to the river bank along several stretches of its course. </p>
<p>The Osun River flows through other human settlements in southwest Nigeria as well as the historic city of Osogbo.</p>
<h2>What are the main sources of the pollution?</h2>
<p>Plastic pollution is the main one. My research has shown that some <a href="https://theconversation.com/nigerian-river-snails-carry-more-microplastics-than-rhine-snails-126622">aquatic snails</a> and <a href="https://theconversation.com/why-microplastics-found-in-nigerias-freshwaters-raise-a-red-flag-147432">insects</a> of the river carry microplastic pollutants. Plastic pollution is a common phenomenon in many inland waters of Nigeria. </p>
<p>Heavy metals also pollute the river. Heavy metals like gold, mercury and cadmium <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144270/">occur naturally</a> in the Earth’s crust. But they can also be introduced through domestic and industrial wastes, or atmospheric sources. Heavy metals can be <a href="https://www.sciencedirect.com/science/article/pii/S2405844020315346">amplified</a> by human activities like waste deposition or mining. Mining loosens heavy metals buried in the earth, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129257/">adding more of them</a> to water. </p>
<p>Artisanal gold mining within the catchments of the Osun River, especially around the Ijesha land area of Osun State, have further worsened the ecological condition of the river and made the water <a href="https://www.premiumtimesng.com/news/top-news/548204-osun-osogbo-festival-govt-warns-devotees-tourists-against-drinking-from-river.html">unsafe</a> for human use. </p>
<p>The impact of illegal gold mining on the river cannot be over-emphasised. First, the impacts have been felt on the river’s water quality, which has deteriorated. This has grave implications for its <a href="http://medcraveonline.com/BIJ/water-pollution-and-aquatic-biodiversity.html">biological diversity</a>.</p>
<p>Aside from the introduction of toxicants, the river, which was once <a href="https://www.tandfonline.com/doi/abs/10.1080/21658005.2017.1357290?journalCode=tzec20">transparent</a> enough for photosynthetic production, is now very turbid (cloudy) with a characteristic gold colour. At extremely low water transparency, a river’s phytoplankton primary production could be <a href="https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1046&context=oak-lake_research-pubs">threatened</a>, and by implication, its secondary (fish) production could also be threatened. It can also cause fish to die by <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/255660.pdf">blocking</a> their gills and destroying their reproductive sites. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/KMmMsKIVuTk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Osun river pollution. Credit: UrbanAlert,</span></figcaption>
</figure>
<p>Another source of pollution is human-generated <a href="https://www.voanews.com/a/nigeria-s-osun-river-sacred-revered-and-increasingly-toxic/6708178.html">waste</a> that lands up in the river. This is due to <a href="https://theconversation.com/nigerias-plastic-pollution-is-harming-the-environment-steps-to-combat-it-are-overdue-177839">poor waste management practice</a> – a feature common in many urban areas in Nigeria. </p>
<h2>What are the solutions?</h2>
<p>The government must first halt all mining near the river until environmental audits have been conducted, placing urgent human welfare ahead of short-term economic gains. Although the river has already suffered significant harm, it is still possible to halt mining operations so that toxicant concentrations do not keep rising and the river can recuperate from the stress of pollution. </p>
<p>Through natural processes, rivers and streams have the ability to <a href="https://www.sciencedirect.com/science/article/pii/S187802961101022X?via%3Dihub">purify</a> themselves. However, in the instance of the Osun River, this can only happen after the various sources of pollution are stopped. </p>
<p>If further gold mining operations are suggested following an environmental audit of the Osun River, it will be crucial to reroute effluents from all natural waters in the basin. A special reservoir can be constructed in a location far away from where people live and make their living.</p>
<p>A polluted and unsafe environment for plants and animals is a reliable indicator of a similarly unsafe environment for people.</p><img src="https://counter.theconversation.com/content/191152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emmanuel O. Akindele receives funding from the British Ecological Society. </span></em></p>The ability of the Osun River to support biodiversity is being threatened by pollution and can only be rescued if the contamination ends.Emmanuel O. Akindele, Senior Lecturer, Obafemi Awolowo UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1891452022-09-26T13:28:59Z2022-09-26T13:28:59ZSome plants can short-circuit the toxic effects of metals – now scientists are trying to harness their power<figure><img src="https://images.theconversation.com/files/480324/original/file-20220822-3952-nba0xr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heavy metals can be toxic to plants - and humans, too.</span> <span class="attribution"><span class="source">Andrii Yalanskyi/Shutterstock</span></span></figcaption></figure><iframe id="noa-web-audio-player" style="border: none" src="https://embed-player.newsoveraudio.com/v4?key=x84olp&id=https://theconversation.com/some-plants-can-short-circuit-the-toxic-effects-of-metals-now-scientists-are-trying-to-harness-their-power-189145&bgColor=F5F5F5&color=D8352A&playColor=D8352A" width="100%" height="110px"></iframe>
<p>At first glance, it’s hard to see what gold, iron, lead, arsenic, silver, platinum and tin have in common. A look at the <a href="https://pubchem.ncbi.nlm.nih.gov/periodic-table/">periodic table</a> will clear up the confusion: they are all heavy metals, typically categorised as those metals with an atomic weight and density at least five times greater than water. </p>
<p>These and other heavy metals occur naturally in the environment, and in some cases, in our bodies. They’re mostly considered harmless but at certain levels of exposure they can be toxic to human, plant and animal life. Being over exposed to heavy metals can stunt plants’ growth and lower seed production. </p>
<p>Some plants have <a href="https://www.sciencedirect.com/science/article/abs/pii/S0065250408602020">evolved traits</a> that increase their tolerance of heavy metals. Many researchers, myself among them, believe that understanding and harnessing these evolutionary traits may allow us to protect agricultural crops from the bad effects of heavy metal toxicity.</p>
<p>My research focuses on improving the tolerance of plants to heavy metals, which is particularly important in a country like South Africa, where <a href="https://theconversation.com/how-mine-dumps-in-south-africa-affect-the-health-of-communities-living-nearby-77113">mining activities contaminate soils</a>. These soils are critical for agriculture. </p>
<p>Even plants in the same family use different strategies to cope with metals. Some take up the metals in their roots and transfer them to their leaves; others take up the metals and hold them (immobile) in their roots. This is important for food security and food safety since we want plants that can limit metal uptake into their edible parts. However, as my colleagues and I outline in a <a href="https://www.mdpi.com/2223-7747/9/12/1781">recent review paper</a>, it’s no easy task to harness these strategies.</p>
<h2>Exposure and risk</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0254629909003159">Heavy metal stress or toxicity</a> in plants happens when they are exposed to heavy metals in the soil. </p>
<p>That exposure is usually the result of waste and pollutants from human activities like agriculture, mining and industry. In South Africa, mining has been a <a href="https://core.ac.uk/download/pdf/222967782.pdf">leading culprit</a> of heavy metal pollution.</p>
<p>This inhibits plants’ growth or their ability to convert sunlight into essential energy through photosynthesis. Or it may affect how they assimilate nutrients, or how they respond to drought or harmful pathogens.</p>
<p>This has implications for the production of food crops. <a href="https://www.researchgate.net/publication/281995800_Effects_and_risk_assessment_of_heavy_metals_in_sediments_of_Dahuanjiang_River_since_tailing_dam_break">Studies around the world</a> have found that heavy metal toxicity can reduce crop yields as well as their quality. <a href="https://www.sciencedirect.com/science/article/pii/S0254629914000696">Medicinal plants</a> can also be affected by heavy metals.</p>
<h2>How plants do it</h2>
<p>Plants have evolved some mechanisms to fend off heavy metals effects. I <a href="https://scholar.google.com/citations?hl=en&user=udMWloIAAAAJ&view_op=list_works&sortby=pubdate">study</a> one of these: signalling mechanisms that plants use to control the uptake of heavy metals – their “immune” response to heavy metals.</p>
<p>In much the same way as the human immune system is alerted to, monitors and responds to a pathogen, plants have evolved signalling mechanisms that help them to regulate their tolerance to heavy metals.</p>
<p>These signalling mechanisms are impressive. For example, plants can trigger signalling events to <a href="https://link.springer.com/article/10.1007/s11120-020-00768-1">release low-molecular-weight ligands (ions or molecules)</a> that tightly bind to the heavy metals and prevent them from moving from the roots.</p>
<p>But they’re far from perfect. As human viruses like HIV and SARS-CoV-2 (the coronavirus behind COVID-19) <a href="https://www.nih.gov/news-events/nih-research-matters/how-covid-19-variants-evade-immune-response">have shown</a>, certain pathogens can short-circuit the immune system. Heavy metals can do the same to the plant’s signalling mechanisms by mimicking essential nutrients; for instance, the metal <a href="https://pubs.rsc.org/en/content/articlehtml/2015/mt/c4mt00304g">vanadium resembles phosphate</a>. </p>
<p>Heavy metals like copper have also been shown to damage the membrane integrity of the cell walls in the roots of plants. Similarly, heavy metals can disrupt the construction of these cell walls; weakened walls make the cell lose structural integrity, which exposes the cellular membranes and causes cell death. </p>
<p>Heavy metals can also impair the work of the plasma membrane, which regulates the transport of material in and out of the plant cells. This blocks the uptake of essential nutrients by negating the function of numerous transporter proteins at work in the plasma membranes.</p>
<h2>Useful lessons</h2>
<p>Despite their shortcomings, these signalling mechanisms are powerful. That’s why I study them: if we can tap into the way in which plants adapt to the threats from heavy metals, there’s a chance that soil contaminated with heavy metals can be rejuvenated through the use of the right plants, or that this tolerance can be passed on to other plants, including food crops.</p>
<p>Our ongoing work, and that of others, is promising, but it’s still early days. Perhaps one day soon, plants’ clever adaptations will signal a change in how we deal with heavy metal toxicity.</p><img src="https://counter.theconversation.com/content/189145/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marshall Keyster receives funding from the Department of Science and Innovation (DSI) and Technology Innovation Agency (TIA). He is affiliated with the University of the Western Cape. </span></em></p>Plants have evolved several ways to deal with heavy metals that might otherwise poison or kill them.Marshall Keyster, Associate professor, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658662021-11-12T13:36:08Z2021-11-12T13:36:08ZNeurotoxins in the environment are damaging human brain health – and more frequent fires and floods may make the problem worse<figure><img src="https://images.theconversation.com/files/428985/original/file-20211028-23-ey0fbd.jpg?ixlib=rb-1.1.0&rect=242%2C177%2C3352%2C2204&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildfire smoke contains a mixture of toxic pollutants that can be harmful to both the lungs and the brain. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/california-wildfires-royalty-free-image/1281624333?adppopup=true">Bloomberg Creative/ Bloomberg Creative Photos via Getty Images</a></span></figcaption></figure><p>In the summer of 2021, a toxic, smoky haze stemming from <a href="https://www.nbcnews.com/western-wildfires">Western wildfires</a> wafted across large parts of the United States, while hurricanes wrought extensive flooding in the southern and eastern U.S. Air quality websites such as <a href="https://www.airnow.gov">AirNow</a> warned of <a href="https://www.npr.org/2021/07/21/1018865569/the-western-wildfires-are-affecting-people-3-000-miles-away">hazardous conditions</a> on the U.S. East Coast from Western forest fires 3,000 miles away, with recommendations to stay indoors. </p>
<p>Journalists reported the immediate impact of lives lost and homes and property destroyed, but more insidious dangers escaped notice. Few people realize that these <a href="https://www.npr.org/2021/09/11/1035241392/climate-change-disasters-mental-health-anxiety-eco-grief">climate change-fueled</a> <a href="https://www.washingtonpost.com/world/interactive/2021/cop26-extreme-weather-climate-change-action/">disasters</a> – both fires and <a href="https://doi.org/10.1080/10807030903051309">floods</a> – could <a href="https://doi.org/10.1080/10962247.2017.1401017">adversely affect human health</a> in longer-term ways. </p>
<p>I’m a <a href="https://scholar.google.com/scholar?as_ylo=2017&q=Arnold+Eiser&hl=en&as_sdt=0,39">scientist-author</a> who studies the links between environmental factors and the development of neurological disorders, which is the <a href="https://rowman.com/ISBN/9781538158074/Preserving-Brain-Health-in-a-Toxic-Age-New-Insights-from-Neuroscience-Integrative-Medicine-and-Public-Health">subject of my recent book</a>. My <a href="https://doi.org/10.1016/j.brainres.2017.06.032">research on this topic</a> adds to a growing body of evidence that <a href="https://www.nytimes.com/2019/07/15/climate/flooding-chemicals-health-research.html">more frequent environmental disasters</a> may be raising <a href="https://doi.org/10.1007/s11356-015-4913-9">human exposure to neurotoxins</a>.</p>
<h2>Neurotoxic smoke</h2>
<p>Many scientists have identified links between <a href="https://doi.org/10.1016/j.bj.2018.06.001">air pollution</a> in various forms, including from <a href="https://theconversation.com/breathing-wildfire-smoke-can-affect-the-brain-and-sperm-as-well-as-the-lungs-166548">forest fire smoke</a>, and an increased risk and prevalence of adverse health effects, including brain disorders. </p>
<p>Wildfire smoke is a mixture of <a href="https://health.ny.gov/environmental/outdoors/air/smoke_from_fire">countless noxious chemical compounds</a>. Fires burning <a href="https://www.theguardian.com/world/2021/aug/09/fires-rage-around-the-world-where-are-the-worst-blazes%20and%20Australia">across the warming planet</a> – from California to Greece and Australia – are adding dangerous particulate matter to the atmosphere that includes <a href="https://doi.org/10.5772/intechopen.97204">neurotoxic heavy metals</a> such as mercury, lead, cadmium and manganese nanoparticles. <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">These toxins</a> are an added environmental burden on top of the pollutants emitted by factories, power plants, trucks, automobiles and other sources. </p>
<p>The greatest potential for health problems comes from minuscule particles, smaller than 2.5 microns – or PM 2.5 (for context, the width of a human hair is typically 50 to 70 microns). This is, in part, because <a href="https://doi.org/10.1164/rccm.201903-0635LE">tiny particles are easily inhaled</a>; from the lungs, they enter the bloodstream and circulate widely throughout the body. <a href="https://doi.org/10.3389/fphys.2020.00155">In the brain</a> they may inflame the microglial cells, the brain’s defensive cells, causing harm to neurons instead of protecting them. Studies show that these extremely tiny particles may damage neurons or brain cells by <a href="https://doi.org/10.1016/j.tins.2009.05.009">promoting inflammation</a>. Brain inflammation can lead to conditions <a href="https://doi.org/10.3233/JAD-180631">like dementia</a> and <a href="https://doi.org/10.1097/JOM.0000000000000451">Parkinson’s disease</a>, a movement disorder in adults.</p>
<p>In addition, <a href="https://doi.org/10.1001/jamapediatrics.2018.3101">prenatal</a> and <a href="https://doi.org/10.1097/EDE.0000000000001109">early-life exposure</a> to air pollution has been linked to an increased risk of autism spectrum disorder in children. Research suggests that <a href="https://doi.org/10.1001/jamanetworkopen.2021.7508">air pollution exposure</a> during these critical periods, particularly in the third trimester of pregnancy and the first few months of life, <a href="https://doi.org/10.1515/tnsci-2016-0005">may impair normal neural development</a>. </p>
<h2>Waterborne neurotoxins</h2>
<p>As part of my book research, I investigated potential links between environmental neurotoxins and related health effects in Finland. Seeking unique environmental factors that might underlie the disproportionately high rates of fatal dementia that occurred in Finland in the past decade, I found that <a href="https://doi.org/10.1016/j.brainres.2017.06.032">water pollution</a> – exacerbated by flooding, use of fertilizer and higher water temperatures – may be affecting brain health. </p>
<p>As I reviewed the environmental concerns in Finland, the widespread presence of <a href="https://www.usgs.gov/centers/kswsc/science/cyanobacterial-blue-green-algal-blooms-tastes-odors-and-toxins-0?qt-science_center_objects=0#qt-science_center_objects">blue-green algae in waterways</a> stood out to me. Though it’s commonly called algae, blue-green algae is actually a type of bacteria called cyanobacteria. These toxic microorganisms thrive and proliferate in warm waterways when excessive nutrients, particularly phosphorus from fertilizer runoff, pour into fresh and brackish water. It produces <a href="https://www.epa.gov/cyanohabs/health-effects-cyanotoxins">cyanotoxins</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blue-green algae bloom on surface of lake with trees in the distance." src="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Harmful blooms of blue-green algae on lakes and ponds can be toxic to humans and dogs alike.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sefton-park-lake-in-liverpool-which-has-been-closed-off-news-photo/1228294229?adppopup=true">Peter Byrne/PA Images via Getty Images</a></span>
</figcaption>
</figure>
<p>One of these cyanotoxins, β-methylamino-L-alanine, or BMAA, is linked to <a href="https://doi.org/10.3389/fnagi.2020.00026">neurodegenerative disorders</a> including amyotrophic lateral sclerosis, or ALS, Parkinson’s disease and Alzheimer’s disease.
In particular I was struck by scientists’ finding high levels of BMAA in <a href="https://doi.org/10.1073/pnas.0914417107">mollusks and fish found in the Baltic Sea</a>, which could potentially play a role in Finland’s high incidence of dementia, as fish is heavily consumed there.</p>
<p>Blue-green algae is found in <a href="https://www.cdc.gov/habs/index.html">rivers, lakes and seas</a>. Its presence is a widespread problem for humans, dogs and wildlife in the U.S. and Canada, as well as around the globe. In 2020, <a href="https://www.bbc.com/news/world-africa-54234396">more than 300 elephants in Botswana died</a> after drinking from water sources contaminated by the cyanobacteria that cause these algal blooms. Blue-green algae is so widely present in Finland that scientists there have developed <a href="https://www.utu.fi/en/news/news/novel-testing-device-will-reveal-whether-water-contains-toxic-blue-green-algae">a quick test to determine whether it is present or not.</a></p>
<h2>Mold neurotoxins</h2>
<p>In Finland, warm, humid air creates the perfect conditions for mold to grow, and water-damaged buildings are particularly susceptible. Some species emit mycotoxins, or mold toxins. Long-term exposure to mycotoxins, even at low levels, can present <a href="https://doi.org/10.1080/00039896.2003.11879142">serious health hazards</a> for both people and animals. </p>
<p>Mold spores are tiny, making them easy to inhale or ingest. Inside the body they can trigger an immune response, leading to chronic inflammation. Ultimately, exposure to these spores may cause <a href="https://doi.org/10.1016/j.shaw.2020.01.003">cognitive impairment</a>, including memory loss, irritability, numbness, tremors and other symptoms. Such a situation is likely to develop after a region has experienced the flooding of residences or workplaces in the weeks after they have been damaged.</p>
<p>Mold toxins, particularly <a href="https://doi.org/10.1002/mnfr.200600137">ochratoxin A</a>, can trigger inflammation that may harm neurons and brain function. It has been <a href="https://doi.org/10.1016/j.jns.2006.06.006">specifically implicated</a> in Parkinson’s disease. </p>
<h2>Reducing risk and a way forward</h2>
<p>Education, greater awareness of environmental health concerns and public action are the best ways to minimize risks from environmental neurotoxins.</p>
<p>By learning to recognize blue-green algae, people may avoid swimming or boating near it and avoid letting their pets near it too. Consumers can advocate for greater environmental monitoring of food and water sources. Exercise that involves sweating can <a href="https://doi.org/10.1155/2017/3676089">help eliminate neurotoxic substances</a>. But before you exercise outdoors, it is prudent to check air quality on an app or website like <a href="https://www.airnow.gov/">AirNow</a>, a partnership of federal, state, local and tribal agencies.</p>
<p>If environmental policies aren’t put into place to mitigate the health risks posed by environmental neurotoxins, <a href="https://doi.org/10.4172/2161-0460.1000249">research suggests</a> that we may continue to experience increases in a variety of neurodegenerative disorders as the toxins rise. Many of these conditions are labeled idiopathic, or lacking a known cause. The neurotoxic connection is rarely considered, and environmental health hazards are <a href="https://doi.org/10.1186/s12909-020-02458-x">often overlooked in American health care</a>. This is in large part because environmental health is rarely taught in medical education, which can lead to a lack of awareness about potential diagnoses related to an environmental illness.</p>
<p>The U.S. Environmental Protection Agency is currently <a href="https://www.epa.gov/system/files/documents/2021-10/draft-policy-assessment-for-the-reconsideration-of-the-pm-naaqs_october-2021_0.pdf">reevaluating</a> air quality standards for particulate matter. A new EPA <a href="https://www.epa.gov/system/files/documents/2021-09/_epaoig_20210929-21-e-0264.pdf">inspector general report</a> calls for a strategic plan to control harmful algal blooms. Ohio, a leading state for public policy initiatives aimed at neurotoxic algal blooms, <a href="https://grist.org/politics/toxic-algae-blooms-are-multiplying-the-government-has-no-plan-to-help">now regulates</a> cyanotoxins in drinking water and advises farmers against adding fertilizer when the ground is saturated or when rain is in the forecast. </p>
<p>Since <a href="https://doi.org/10.1038/s41586-019-1468-9">climate change may be a driver for rising neurotoxins</a>, cutting greenhouse gas emissions and ensuring better environmental stewardship are essential to human health. Achieving this will require strong international and domestic efforts and a wide range of interventions by governments around the world. But all of these efforts must begin with a deeper and more widespread understanding of the profound nature of this problem – which should be a universal, nonpartisan concern. </p>
<p>[<em>Over 115,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-newsletter-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/165866/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold R. Eiser does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Pollution from more frequent floods and wildfires – exacerbated by the warming climate – is threatening human health and poses particular risks to the brain.Arnold R. Eiser, Emeritus Professor of Medicine, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1632222021-08-17T13:44:40Z2021-08-17T13:44:40ZTiny 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/1561212021-03-18T01:38:25Z2021-03-18T01:38:25ZTeeth contain detailed records of lead contamination in humans and other primates<figure><img src="https://images.theconversation.com/files/390240/original/file-20210318-17-691fba.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4478%2C2981&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Lead is a powerful toxin. It can affect almost every organ and system in the body, and babies are extremely vulnerable to its harmful effects. Infants’ brains grow rapidly during the first year of life, and even low levels of lead exposure have been associated with brain development deficits. </p>
<p>It’s also more common than you might think. Many popular baby foods and infant formulas available in the US were recently <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969718334442">found</a> to contain elevated levels of lead and other heavy metals. </p>
<p>Few studies have examined Australian-sourced infant formulas and foods, and those that have show lead levels are generally low. However, more than half of the products sold in Australia are imported — so international problems are still a concern.</p>
<p>Lead leaves traces in growing teeth. In a new <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/bies.202000298">study</a> published in BioEssays, we used a very sensitive technique called laser-ablation mapping to analyse the teeth of young macaque monkeys. We found traces of lead from both commercial infant formula and the milk of their own mothers. This provided clues of events that happened years, or even decades, earlier.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-safe-is-your-baby-food-155443">How safe is your baby food?</a>
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<figure class="align-center ">
<img alt="Diagram showing the process of laser-ablation mapping of teeth." src="https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=289&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=289&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=289&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=364&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=364&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386794/original/file-20210227-15-19cb2m2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=364&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How laser-ablation mapping works: a) the tooth is sliced open; b) a small sample is vaporised by laser; c) the levels of different elements over the span of tooth growth is determined with a mass spectrometer.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/ncomms15493">Arora et al. (2017), Nature Communications</a></span>
</figcaption>
</figure>
<h2>The stories teeth tell</h2>
<p>The development of teeth records each day of our childhoods, <a href="https://thereader.mitpress.mit.edu/birth-certificate-neonatal-lines/">including birth</a>, as well as the chemistry of the food and water we consume. Public health specialists in Australia and the US have worked out <a href="https://www.scientificamerican.com/custom-media/mount-sinai/in-teeth-markers-of-disease/">how to measure</a> infants’ metal intake using the concentrations of different elements and growth lines in teeth. </p>
<p>Our team honed this analytical model through a 2013 <a href="https://www.nature.com/articles/nature12169">study</a> of human, monkey, and Neanderthal nursing histories. We tracked changes in the trace element barium, which is stored in bones and teeth, and concentrated in calcium-rich milk. While barium is toxic in large amounts or certain compounds, small amounts in milk and foods like Brazil nuts do not seem to be particularly harmful. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/got-milk-our-breastfeeding-habits-are-older-than-you-think-14577">Got milk? Our breastfeeding habits are older than you think</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386789/original/file-20210227-19-1abud9u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Changes in the concentrations of different elements may indicate milk intake following birth (blue to orange), the end of exclusive suckling (orange to green), and the cessation of milk intake (green to blue) in primate teeth. The neonatal line (marked NL) marks birth, and identifying microscopic daily growth increments allows precise age estimates of childhood dietary changes, health challenges, and lead exposure.</span>
<span class="attribution"><a class="source" href="https://LINK.TK">Smith et al. BioEssays (2021).</a></span>
</figcaption>
</figure>
<p>In our new study we were able to show a precise correspondence between the onset of suckling and elevated lead levels, which disappeared when the macaque infants stopped consuming Enfamil formula or mothers’ milk. Captive monkey mothers may be exposed to lead from water pipes or old paint, as lead was once a widely used paint additive that has a pleasant sweet taste.</p>
<h2>How barium and lead get into teeth</h2>
<p>Milk is an important source of calcium for infant growth, but it may also contain other less helpful ingredients. Barium and lead are known as <em>bone-seeking elements</em>: when abundant they can transfer to the bloodstream and substitute for calcium in the hard mineral that strengthens our growing bones and teeth. </p>
<p>We’ve also discovered that when young monkeys become very sick, they may tap their skeletal stores of calcium to maintain metabolic balance, also inadvertently releasing lead and barium from bones back into the bloodstream and ultimately locking them into growing teeth. This form of elemental recycling means that we can also explore health histories after individuals stop nursing. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=422&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=422&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=422&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=531&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=531&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386796/original/file-20210227-23-153bzpy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=531&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Monkey molar showing formation timing on the microscope image (left) and lead concentrations (normalized to calcium on the right). Lead in the enamel drops markedly with the cessation of formula (Enfamil) intake at 112 days of age (red arrows), which is even more apparent in the underlying dentine. A second macaque infant provided Enfamil in 1976–77 also implicates this commercial source, consistent with reports of metal contamination of various human infant formulas. Image credit: Smith et al. (2021) <em>BioEssays</em>.</span>
</figcaption>
</figure>
<p>The origin of lead found in humans’ teeth is more difficult to pin down than it is for captive monkeys. Likely factors range from <a href="https://www.theguardian.com/australia-news/2021/feb/22/lead-levels-among-children-in-south-australias-port-pirie-reach-decade-high">environmental pollution</a> and <a href="https://www.scoop.co.nz/stories/AK2102/S00130/no-level-of-lead-is-safe-in-drinking-water-says-master-plumbers.htm">drinking water</a> to soils used to grow food. Public health crises such as the <a href="https://en.wikipedia.org/wiki/Flint_water_crisis">water contamination in Flint, Michigan</a> in 2014–2015 are currently under investigation to better understand the timing and degree of lead exposure in children from that region. </p>
<p>Our new study also revealed wild primates can be exposed to lead in their natural environments. We found lead bands in the teeth of baboons that grew up in Ethiopia and orangutans from Borneo and Sumatra. While human industrial activity may explain some of these cases, we <a href="https://advances.sciencemag.org/content/4/10/eaau9483.full">recently uncovered</a> lead intake in Neanderthal children roughly 250,000 years ago. </p>
<p>In that instance the lead was likely derived from geological deposits in southeast France, a region that has since been commercially mined. The two Neanderthals likely ate or drank something contaminated with lead, although we couldn’t rule out the possibility they may have inhaled lead released into the air through combustion during the winter and early spring.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-teeth-can-tell-about-the-lives-and-environments-of-ancient-humans-and-neanderthals-104923">What teeth can tell about the lives and environments of ancient humans and Neanderthals</a>
</strong>
</em>
</p>
<hr>
<p>Studies of nonhuman primates and ancient hominins help us to better understand our own physiology, including the sensitive recording systems inside our own bodies. They point to complex environmental problems as well as the dangers of the natural world. </p>
<p>Our study adds to the evidence that lead exposure is common around the world. To safeguard our health, we need better regulation of food, water, and air quality.</p><img src="https://counter.theconversation.com/content/156121/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tanya M. Smith receives funding from the Australian Academy of Science and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Christine Austin receives funding from the National Institutes of Health, USA. </span></em></p>Like rings in tree trunks, the layers of our teeth carry a detailed record of our growth — and reveal lead contamination is common.Tanya M. Smith, Professor in the Australian Research Centre for Human Evolution & Griffith Centre for Social and Cultural Research, Griffith UniversityChristine Austin, Assistant Professor of Environmental Medicine and Public Health, Icahn School of Medicine at Mount SinaiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1554432021-02-22T13:26:06Z2021-02-22T13:26:06ZHow safe is your baby food?<figure><img src="https://images.theconversation.com/files/385363/original/file-20210219-19-p33c1o.jpg?ixlib=rb-1.1.0&rect=92%2C423%2C4552%2C2996&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One study found that 95% of baby foods tested contained at least one heavy metal.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/baby-being-fed-royalty-free-image/522813035">Plume Creative via Getty Images</a></span></figcaption></figure><p>Heavy metals including lead, arsenic and mercury can be found in commercial baby foods at levels well above what the federal government considers safe for children, a new <a href="https://oversight.house.gov/sites/democrats.oversight.house.gov/files/2021-02-04%20ECP%20Baby%20Food%20Staff%20Report.pdf">congressional report</a> warns.</p>
<p>Members of Congress asked seven major baby food makers to hand over test results and other internal documents after a <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">2019 report</a> found that, out of 168 baby food products, 95% contained at least one heavy metal. Foods with rice or root vegetables, like carrots and sweet potatoes, had some of the highest levels, but they weren’t the only ones. </p>
<p>How concerned should parents be and what can they do to reduce their child’s exposure?</p>
<p>As a professor and pharmacist, I have investigated health safety concerns for several years <a href="https://doi.org/10.1177/1060028019881692">in drugs</a> and <a href="https://doi.org/10.1177/1060028019900504">dietary supplements</a>, including contamination with heavy metals and the chemical <a href="http://doi.org/10.1001/jamanetworkopen.2020.35158">NDMA</a>, a likely carcinogen. Here are answers to four questions parents are asking about the risks in baby food.</p>
<h2>How do heavy metals get into baby food?</h2>
<p>Heavy metals come from the natural erosion of the <a href="http://doi.org/10.1155/2011/870125">Earth’s crust</a>, but humans have dramatically accelerated environmental exposure to heavy metals, as well. </p>
<p>As <a href="https://www.eia.gov/energyexplained/coal/coal-and-the-environment.php">coal</a> is burned, it releases heavy metals into the air. Lead was commonly found in gasoline, paint, pipes and pottery glazes for decades. A pesticide with both <a href="http://doi.org/10.1289/ehp.114-a470">lead and arsenic</a> was widely used on crops and in orchards until it was banned in 1988, and phosphate-containing fertilizers, including organic varieties, still contain small amounts of <a href="https://doi.org/10.1007/BF00747683">cadmium, arsenic, mercury and lead.</a> </p>
<p>These heavy metals still contaminate soil, and irrigation can expose more soil to heavy metals in water.</p>
<p>When food is grown in contaminated soil and irrigated with water containing heavy metals, the food becomes contaminated. Additional heavy metals can be introduced during manufacturing processes.</p>
<p>The United States has made major strides to reduce the use of fossil fuels, filter pollutants and remove lead from many products such as gasoline and paint. This reduced exposure to <a href="https://www.epa.gov/air-trends/lead-trends">lead in the air</a> by 98% from 1980 to 2019. Processes can now also remove a proportion of the heavy metals from <a href="http://doi.org/10.1016/j.chemosphere.2019.04.198">drinking water</a>. However, the heavy metals that accumulated in the soil over the decades is an ongoing problem, especially in <a href="http://doi.org/10.1021/es400521h">developing countries</a>. </p>
<h2>How much heavy metal is too much?</h2>
<p>The <a href="https://apps.who.int/food-additives-contaminants-jecfa-database/search.aspx">World Health Organization</a> and the <a href="https://www.fda.gov/food/metals-and-your-food/survey-data-lead-womens-and-childrens-vitamins">Food and Drug Administration</a> have defined tolerable daily intakes of heavy metals. However, it’s important to recognize that for many heavy metals, including lead and arsenic, there is no daily intake that is completely devoid of long-term health risk.</p>
<p>For lead, the FDA considers 3 micrograms per day or more to be cause for concern <a href="https://www.fda.gov/food/metals-and-your-food/lead-food-foodwares-and-dietary-supplements">in children</a>, well below the level for adults (12.5 micrograms per day).</p>
<p>Young children’s bodies are smaller than adults, and lead can’t be <a href="http://doi.org/10.1515/intox-2015-0009">stored as readily in the bone</a>, so the same dose of heavy metals causes much greater blood concentrations in young children where it can do more damage. In addition, young brains are more rapidly developing and are therefore at greater risk of neurological damage.</p>
<figure class="align-center ">
<img alt="Baby food jars" src="https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=507&fit=crop&dpr=1 754w, https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=507&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/385364/original/file-20210219-23-8bp35z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=507&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Root vegetables, such as sweet potatoes and carrots, have some of the highest levels of heavy metals.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/hand-spooning-baby-food-royalty-free-image/95468925">Tetra Images via Getty Images</a></span>
</figcaption>
</figure>
<p>These lead levels are <a href="https://www.fda.gov/food/metals-and-your-food/lead-food-foodwares-and-dietary-supplements">about one-tenth</a> of the dose needed to achieve a blood lead concentration associated with major neurological problems, including the development of behavioral issues like aggression and attention deficit disorder. That doesn’t mean lower doses are safe, though. Recent research shows that <a href="http://doi.org/10.1515/intox-2015-0009">lower blood lead levels</a> still impact neurological function, just not as dramatically.</p>
<p>For other heavy metals, the daily intake considered tolerable is based on <a href="https://apps.who.int/food-additives-contaminants-jecfa-database/search.aspx">body weight</a>: mercury is 4 micrograms per kilogram of body weight; arsenic is not currently defined but before 2011 it was 2.1 micrograms per kilogram of body weight. </p>
<p>Like with lead, there is a considerable safety margin between the tolerable dose and the dose that poses high risk of causing neurological harm, <a href="http://doi.org/10.1515/intox-2015-0009">anemia</a>, <a href="http://doi.org/10.1155/2011/870125">liver and kidney damage and an increased risk of cancer</a>. But even smaller amounts still carry risks.</p>
<p>One example of the exposure infants can face is a <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">brand of carrot baby food</a> found to have 23.5 parts of lead per billion, <a href="http://www.endmemo.com/sconvert/ppbug_g.php">equivalent</a> to 0.67 micrograms of lead per ounce. Since the average 6-month-old eats 4 ounces of vegetables a day, that would be 2.7 micrograms of lead a day – almost the maximum tolerable daily dose.</p>
<h2>What can parents do to reduce a child’s exposure?</h2>
<p>Since the amount of heavy metals varies so dramatically, food choices can make a difference. Here are a few ways to reduce a young child’s exposure.</p>
<p>1) Minimize the use of <a href="https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-action-level-inorganic-arsenic-rice-cereals-infants?">rice-based products</a>, including rice cereal, puffed rice and rice-based teething biscuits. Switching from rice-based products to those made with oats, corn, barley or quinoa could reduce the ingestion of arsenic by 84% and total heavy metal content <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">by about 64%</a>, according to the study of 168 baby food products by the group Healthy Babies Bright Futures.</p>
<p>Using frozen banana pieces or a clean washcloth instead of a rice cereal based teething biscuit was found to reduce the total heavy metal exposure <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">by about 91%</a>.</p>
<p>2) Switch from fruit juices to water. Fruit juice is not recommended for small children because it is laden with sugar, but it also is a source of heavy metals. Switching to water could reduce the intake of heavy metals <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">by about 68%</a>, according to the report.</p>
<p>3) Alternate between root vegetables, such as carrots and sweet potatoes, and other vegetables. The roots of plants are in closest contact with the soil and have higher concentrations of heavy metals than other vegetables. Switching from carrots or sweet potatoes to other vegetables could decrease the total heavy metal content on that day <a href="https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf">by about 73%</a>. Root vegetables have vitamins and other nutrients, so you don’t have to abandon them altogether, but use them sparingly.</p>
<p>Making your own baby food may not reduce your child’s exposure to heavy metals. It depends on the heavy metal dosage in each of the ingredients that you are using. Organic may not automatically mean the heavy metal content is lower because soil could have been contaminated for generations before its conversion, and neighboring farm water runoff could contaminate common water sources.</p>
<h2>Is anyone doing anything about it?</h2>
<p>The <a href="https://oversight.house.gov/sites/democrats.oversight.house.gov/files/2021-02-04%20ECP%20Baby%20Food%20Staff%20Report.pdf">congressional report</a> calls for the FDA to <a href="https://www.fda.gov/food/cfsan-constituent-updates/fda-response-questions-about-levels-toxic-elements-baby-food-following-congressional-report">better define acceptable limits</a> for heavy metals in baby food. It points out that the heavy metal levels found in some baby foods far exceed the maximum levels allowed in bottled water. It also recommends standards for testing in the industry, and suggests requiring baby food makers to report heavy metals amounts on their product labels so parents can make informed choices.</p>
<p>Baby food manufacturers are also discussing the issue. The <a href="https://www.edf.org/media/baby-food-council-taking-challenge-reducing-heavy-metals-young-kids-food">Baby Food Council</a> was created in 2019 to bring together major infant and toddler food companies and advocacy and research groups with the goal of reducing heavy metals in baby food products. They created a <a href="https://foodscience.cals.cornell.edu/industry-partnership-program/cifs-ipp-councils/">Baby Food Standard and Certification Program</a> to work collaboratively on testing and certification of raw ingredients. Ultimately, baby food makers will need to consider changing farm sources of raw ingredients, using fewer seasonings and altering processing practices.</p>
<p>The U.S. has made important inroads in reducing heavy metals in air and water since the 1980s, dramatically lowering exposure. With additional focus, it can further reduce heavy metal exposure in baby food, too.</p>
<p>[<em>Understand new developments in science, health and technology, each week.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-understand">Subscribe to The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/155443/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>C. Michael White 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>Reports from baby food companies show questionable levels of arsenic, lead and other heavy metals. Here’s what parents need to know.C. Michael White, Distinguished Professor and Head of the Department of Pharmacy Practice, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1537972021-02-16T02:38:22Z2021-02-16T02:38:22ZWe tested tiger snake scales to measure wetland pollution in Perth. The news is worse than expected<figure><img src="https://images.theconversation.com/files/382156/original/file-20210203-19-16ycbb1.jpg?ixlib=rb-1.1.0&rect=6%2C18%2C4154%2C1809&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Australia’s wetlands are home to a huge range of stunning flora and fauna, with large snakes often at the top of the food chain. </p>
<p>Many wetlands are located near urban areas. This makes them particularly susceptible to contamination as stormwater, urban drainage and groundwater can wash metals — such as arsenic, cadmium, lead and mercury — into the delicate ecosystem.</p>
<p>We know many metals can travel up the food chain when they’re present in the environment. So to assess contamination levels, we caught highly venomous tiger snakes across wetlands in Perth, and repurposed laser technology to measure the metals they accumulated. </p>
<p>In our <a href="https://www.sciencedirect.com/science/article/pii/S0269749121001251">new paper</a>, we show metal contamination in wild wetland tiger snakes is chronic, and highest in human-disturbed wetlands. This suggests all other plants and animals in these wetlands are likely contaminated as well.</p>
<h2>34 times more arsenic in wild wetland snakes than captive snakes</h2>
<p>Urban growth and landscape modification often introduces metals into the surrounding environment, such as mining, landfill and waste dumps, vehicles and roadworks, and agriculture.</p>
<p>When they reach wetlands, sediments collect and store these metals for hundreds of years. And if a wetland’s natural water levels are lowered, from agricultural draining for example, sediments can become exposed and erode. This releases the metals they’ve been storing into the ecosystem. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A reflective lake, with green vegetation surrounding it" src="https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384344/original/file-20210215-13-ur2z58.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">The wetland in Yanchep National Park, Perth, was supposed to be our ‘clean’ comparison site. Its levels of metal contamination was unprecedented.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This is what we suspect happened in Yanchep National Park’s wetland, which was supposed to be our “clean” comparison site to more urban wetlands. But in a <a href="https://link.springer.com/article/10.1007/s00244-020-00724-z">2020 study</a> looking at sediment contamination, we found this wetland had higher levels of selenium, mercury, chromium and cadmium compared to urban wetlands we tested. </p>
<p>And at Herdsman Lake, our most urban wetland five minutes from the Perth city centre, we found concentrations of arsenic, lead, copper and zinc in sediment up to four times higher than <a href="https://link.springer.com/article/10.1007/s00244-020-00724-z">government guidelines</a>. </p>
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Read more:
<a href="https://theconversation.com/does-australia-really-have-the-deadliest-snakes-we-debunk-6-common-myths-145765">Does Australia really have the deadliest snakes? We debunk 6 common myths</a>
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<p>In <a href="https://www.sciencedirect.com/science/article/pii/S0269749121001251">our new study</a> on tiger snake scales, we compared the metal concentrations in wild wetland tiger snakes to the concentrations that naturally occurs in captive-bred tiger snakes, and to the sediment in the previous study. </p>
<p>We found arsenic was 20-34 times higher in wild snakes from Herdsman Lake and Yanchep National Park’s wetland. And snakes from Herdsman Lake had, on average, eight times the amount of uranium in their scales compared to their captive-bred counterparts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Tiger snake on the ground, near rubbish." src="https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384180/original/file-20210215-23-jk8pk.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">Our research confirmed snake scales are a good indicator of environmental contamination.</span>
<span class="attribution"><span class="source">Damian Lettoof</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Tiger snakes usually prey on frogs, so our results suggest frogs at these lakes are equally as contaminated. </p>
<p>We know for many organisms, exposure to a high concentration of metals is fatally toxic. And when contamination is chronic, it can be “neurotoxic”. This can, for example, change an organism’s behaviour so they eat less, or don’t want to breed. It can also interfere with their normal cellular function, compromising immune systems, DNA repair or reproductive processes, to name a few. </p>
<p>Snakes in general appear relatively resistant to the toxic effects of metal contamination, but we’re currently investigating what these levels of contamination are doing to tiger snakes’ health and well-being. </p>
<h2>Our method keeps snakes alive</h2>
<p>Snakes can be a great indicator of environmental contamination because they generally live for a long time (over 10 years) and don’t travel too far from home. So by measuring metals in older snakes, we can assess the contamination history of the area they were collected from.</p>
<p>Typically, scientists use liver tissue to measure biological contamination since it acts like a filter and retains a substantial amount of the contaminants an animal is exposed to. </p>
<p>But a big problem with testing the liver is the animal usually has to be sacrificed. This is often not possible when studying threatened species, monitoring populations or working with top predators.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two black swans in a lake, near cut grass" src="https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384349/original/file-20210215-18-1oe0y4y.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">Sediment in Herdsman Lake had four times higher heavy metal levels than what government guidelines allow.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>In more recent years, <a href="https://setac.onlinelibrary.wiley.com/doi/abs/10.1002/etc.4622">studies</a> have taken to measuring metals in external “keratin” tissues instead, which include bird feathers, mammal hair and nails, and reptile scales. As it grows, keratin can accumulate metals from inside the body, and scientists can measure this without needing to kill the animal.</p>
<p>Our research used “laser ablation” analysis, which involves firing a focused laser beam at a solid sample to create a small crater or trench. Material is excavated from the crater and sent to a mass spectrometer (analytical machine) where all the elements are measured.</p>
<p>This technology was originally designed for geologists to analyse rocks, but we’re among the first researchers applying it to snake scales.</p>
<p>Laser ablation atomises the keratin of snake scales, and allowed us to accurately measure 19 contaminants from each tiger snake caught over three years around different wetlands. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wild tiger snake" src="https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382168/original/file-20210203-19-10dx5z.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">Snakes generally appear resistant to the toxic effects of heavy metals.</span>
<span class="attribution"><span class="source">Kristian Bell/Shutterstock</span></span>
</figcaption>
</figure>
<h2>We need to minimise pollution</h2>
<p>Our research has confirmed snake scales are a good indicator of environmental contamination, but this is only the first step. </p>
<p>Further research could allow us to better use laser ablation as a cost-effective technology to measure a larger suite of metals in different parts of the ecosystem, such as in different animals at varying levels in the food chain. </p>
<p>This could map how metals move throughout the ecosystem and help determine whether the health of snakes (and other top predators) is actually at risk by these metal levels, or if they just passively record the metal concentrations in their environment.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/our-toxic-legacy-bushfires-release-decades-of-pollutants-absorbed-by-forests-145542">Our toxic legacy: bushfires release decades of pollutants absorbed by forests</a>
</strong>
</em>
</p>
<hr>
<p>It’s difficult to prevent contaminants from washing into urban wetlands, but there are a number of things that can help minimise pollution. </p>
<p>This includes industries developing strict spill management requirements, and local and state governments deploying storm-water filters to catch urban waste. Likewise, thick vegetation buffer zones around the wetlands can filter incoming water.</p><img src="https://counter.theconversation.com/content/153797/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Damian Lettoof receives funding from the Holsworth Wildlife Research Endowment. </span></em></p><p class="fine-print"><em><span>Kai Rankenburg, Monique Gagnon, and Noreen Evans do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research fired laser beams on tiger snake scales, and found arsenic was 20-34 times higher in wild wetland snakes than in captive snakes.Damian Lettoof, PhD Candidate, Curtin UniversityKai Rankenburg, Researcher, Curtin UniversityMonique Gagnon, Researcher, Curtin UniversityNoreen Evans, Professor, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1494102020-11-05T15:16:32Z2020-11-05T15:16:32ZMetal pollution is leaving scallops helpless against crabs and lobsters<figure><img src="https://images.theconversation.com/files/367728/original/file-20201105-20-iif35j.JPG?ixlib=rb-1.1.0&rect=8%2C0%2C5455%2C3071&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Will Notley</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Shellfish such as scallops, mussels and oysters – bivalve molluscs – <a href="http://www.int-res.com/abstracts/meps/v211/p157-167/">readily take up tiny specs of metals</a> into their tissues and shells. In sufficient concentrations this can harm their growth and survival chances, and even threaten the health of any human who eats their contaminated meat. Such shellfish provide <a href="http://www.fao.org/state-of-fisheries-aquaculture">one-quarter of the world’s seafood</a>, so the impact of pollution from the “heavy metals” such as lead, zinc and copper, is hugely important.</p>
<p>We recently investigated the effects of metal pollution on the great scallop, <em>Pecten maximus</em>, for a new <a href="https://www.sciencedirect.com/science/article/pii/S0048969720365499">scientific study</a>. This is a common species which supports the <a href="https://www.gov.uk/government/statistics/uk-sea-fisheries-annual-statistics-report-2019">most valuable fishery</a> in England and the third most valuable in the UK overall. </p>
<p>We first discovered these effects of pollution by chance. While carrying out routine stock assessment surveys around the Isle of Man, a self-governing island that lies between Britain and Ireland, we noticed that scallops found on the Laxey fishing ground off the east coast were much more likely to have lethally damaged shells than scallops from elsewhere.</p>
<p>Laxey is famous for the world’s largest working <a href="https://www.visitisleofman.com/experience/great-laxey-wheel-and-mine-trail-p1292251">waterwheel</a>, a spectacular example of Victorian engineering used to pump water <a href="https://www.nmrs.org.uk/mines-map/metal/isle-man-mines/laxey-mine/">from a mine</a> which produced lead, copper, silver and zinc. The mine closed in 1929, but its legacy is that sediments in the rivers, estuary and sea waters around Laxey are unnaturally high in metals. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large red and white wheel next to a tower." src="https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367722/original/file-20201105-17-1tjxqsy.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">The 22-metre diameter Laxey Wheel is now a tourist attraction.</span>
<span class="attribution"><span class="source">Powerofflowers / shutterstock</span></span>
</figcaption>
</figure>
<p>It looked as though metal pollution may be responsible for the damaged shells we discovered. To test this hypothesis, we analysed the strength of scallop shells that had been collected from Laxey and other fishing grounds around the Isle in both 2004 and 2013. In both groups the shells from Laxey were found to be significantly weaker than those from all other areas.</p>
<p>A detailed analysis revealed the Laxey shells were proportionally thinner than shells found at other areas, and that the internal structure of shells contained a disruption, or fault line. We were not able to detect metals in the shells themselves, but we think that even in low quantities the metals are either affecting the physiology of the scallops or disrupting chemical reactions during the mineralisation (shell-growing) process.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of heavy metal pollution and impact on scallops." src="https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=460&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=460&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367727/original/file-20201105-21-1ke2lxx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=460&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scallops with unnaturally thin shells are also more likely to be damaged when being captured.</span>
<span class="attribution"><span class="source">Stewart et al (2020)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In ecotoxicology terms, what we observed is called a <a href="https://www.oecd.org/chemicalsafety/testing/49963576.pdf">non-apical endpoint effect</a>. Weakened shells don’t directly kill scallops, but instead leave them more vulnerable to mortality. Such responses are rarely considered when assessing the effects of environmental contaminants, but could have significant implications. This is a concern, because the levels of metal contamination we observed were generally below the current regulatory limits thought to affect marine life, and the scallops were considered perfectly safe to eat.</p>
<h2>Metals at sea</h2>
<p>It is remarkable that mining from 100 years ago is still affecting marine life in this way. But, given that metal contamination is <a href="https://link.springer.com/article/10.1007/s40726-015-0018-9">a common and increasing threat</a> in coastal areas around the world, and that many other shellfish and marine species such as corals produce calcified structures chemically-similar to scallop shells, we believe metals may be having unseen effects on a large scale. We may therefore need to rethink how we assess and manage the risks of metal contamination.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing four scallop shells" src="https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=665&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=665&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=665&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=836&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=836&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367729/original/file-20201105-16-rc110n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=836&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">King scallops showing different levels of damage after being caught in dredges around the Isle of Man. This type of damage is much more likely in areas contaminated with heavy metals.</span>
<span class="attribution"><span class="source">Bryce Stewart</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Metals are a natural component of marine systems and in trace concentrations may be essential for supporting life. However, human activities have <a href="https://oap.ospar.org/en/ospar-assessments/intermediate-assessment-2017/pressures-human-activities/contaminants/metals-fish-shellfish/">elevated their concentrations</a> in many marine environments to the point where they have become toxic. This pollution comes from <a href="https://scialert.net/fulltext/?doi=jas.2004.1.20">a variety of sources</a> such as run off from mining, agricultural and industrial activity; offshore oil and gas exploitation; and leaching of anti-fouling paint from ships hulls. As a result, metal pollution tends to be highest in estuaries, around ports and in inshore waters. </p>
<p>Despite stricter recent regulations controlling the use of metals in marine environments, they continue to be an increasing threat. This is because heavy metals are highly persistent (they do not disappear over time) and ongoing coastal development and bottom-towed fishing gear is <a href="https://www.sciencedirect.com/science/article/abs/pii/S0269749112003284">remobilising contaminated sediments</a>. Climate change is also <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12048">exacerbating the threat</a> because higher rainfall is increasing run-off from contaminated areas, and ocean warming and acidification is increasing the rate of uptake and toxicity of metals in seawater.</p>
<p>Most previous studies have concentrated on the direct effects of metals on shellfish <a href="https://www.sciencedirect.com/science/article/abs/pii/0141113687900523">survival</a> or <a href="https://www.sciencedirect.com/science/article/pii/B9780081006740000217">food safety</a>. However, our new study has unearthed that even relatively low concentrations of metal contamination appears to be causing scallops to grow weaker shells. This leaves the scallops more vulnerable to being <a href="https://link.springer.com/article/10.1007/s00227-002-0977-4">eaten by crabs and lobsters</a> and to disturbance from storms and fishing activity, with potentially substantial ecological and economic repercussions.</p><img src="https://counter.theconversation.com/content/149410/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bryce Stewart receives funding from the European Maritime and Fisheries Fund, the Economic and Social Research Council, the Global Challenges Research Fund and the Blue Marine Foundation. He is a member of the ICES Scallop Working Group, the Marine Conservation Society and the Yorkshire Wildlife Trust </span></em></p><p class="fine-print"><em><span>Roland Kröger receives funding from EPSRC, NERC, Leverhulme Trust, European Comission. </span></em></p>New research points to ‘heavy metals’ having unseen effects on a much larger scale than previously thought.Bryce Stewart, Senior Lecturer in Marine Ecosystem Management, University of YorkRoland Kröger, Professor, Department of Physics, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1405962020-06-21T20:07:48Z2020-06-21T20:07:48ZBan on toxic mercury looms in sugar cane farming, but Australia still has a way to go<figure><img src="https://images.theconversation.com/files/342920/original/file-20200619-70386-o94vpv.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Phil / CC BY (https://creativecommons.org/licenses/by/2.0)</span></span></figcaption></figure><p>This month, federal authorities finally announced an upcoming <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">ban on mercury-containing pesticide</a> in Australia. We are one of the last countries in the world to do so, despite <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2366450/">overwhelming evidence</a> over more than 60 years that mercury use as fungicide in agriculture is dangerous.</p>
<p>Mercury is a toxic element that damages human health and the environment, even in low concentrations. In humans, mercury exposure is <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">associated with</a> problems such as kidney damage, neurological impairment and delayed cognitive development in children.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-emits-mercury-at-double-the-global-average-82577">Australia emits mercury at double the global average</a>
</strong>
</em>
</p>
<hr>
<p>The ban will prevent about <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">5,280 kilograms of mercury</a> entering the Australian environment each year.</p>
<p>But Australia is yet to ratify an international treaty to reduce mercury emissions from other sources, such as the dental industry and coal-fired power stations. This is our next challenge.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342912/original/file-20200619-70415-142qyoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Prime Minister Scott Morrison visiting a sugar cane farm in 2019. Mercury-containing pesticides will be banned.</span>
<span class="attribution"><span class="source">Cameron Laird/AAP</span></span>
</figcaption>
</figure>
<h2>A mercury disaster</h2>
<p>Mercury became a popular pesticide ingredient for agriculture in the early 1900s, and a number of poisoning events ensued throughout the world. </p>
<p>They include the <a href="https://www.researchgate.net/publication/330958073_1971_Iraq_Poison_Grain_Disaster_and_Methylmercury_Hawraz">Iraq grain disaster</a> in 1971-72, when grain seed treated with mercury was imported from Mexico and the United States. The seed was not meant for human consumption, but rural communities used it to make bread, and 459 people died. </p>
<p>In the decades since, most countries have banned the production and/or use of mercury-based pesticides on crops. <a href="https://apvma.gov.au/node/12591">In 1995</a> Australia discontinued their use in most applications, such as turf farming.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342914/original/file-20200619-70391-181w1th.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Emissions of the element mercury are a threat to human health and the environment.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Hydrargyrum.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Despite this, authorities exempted a fungicide containing mercury known as Shirtan. They <a href="http://classic.austlii.edu.au/au/journals/PrecedentAULA/2005/56.pdf">restricted</a> its use to sugar cane farming in Queensland, New South Wales, Western Australia and the Northern Territory.</p>
<p><a href="http://www.canegrowers.com.au/page/advocacy/key-issues/environment">According to</a> the sugar cane industry, about 80% of growers use Shirtan to treat pineapple sett rot disease.</p>
<p>But this month, the Australian Pesticides and Veterinary Medicines Authority <a href="https://apvma.gov.au/sites/default/files/gazette_02062020.pdf">cancelled the approval</a> of the mercury-containing active ingredient in Shirtan, methoxyethylmercuric chloride. The decision was made at the request of the ingredient’s manufacturer, Alpha Chemicals. </p>
<p>Shirtan’s <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">registration</a> was cancelled last week. It will no longer be produced in Australia, but existing supplies can be sold to, and used by, sugar cane farmers for the next year until it is fully banned.</p>
<h2>Workers and nature at risk</h2>
<p>Over the past 25 years, Australia’s continued use of Shirtan allowed <a href="http://www.environment.gov.au/system/files/consultations/4068cac4-a2ba-4036-a9e0-7bdee4f558fd/files/final-report-cost-benefits-mercury.pdf">about 50,000 kilograms of mercury</a> into the environment. The effect on river and reef ecosystems is largely unknown. </p>
<p>What is known is that mercury can be toxic even at very low concentrations, and research is needed to understand its ecological impacts.</p>
<p>The use of mercury-based pesticide has also created a high risk of exposure for sugar cane workers. At most risk are those not familiar with safety procedures for handling toxic materials, and who may have been poorly supervised. This risk has been exacerbated by the use itinerant workers, particularly those from a non-English speaking background. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=321&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=321&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=321&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=403&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=403&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342924/original/file-20200619-70376-8a677k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=403&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">South Sea Islanders hoeing a cane field in Queensland, 1902. Cane workers have long been exposed to mercury.</span>
<span class="attribution"><span class="source">State Library of Queensland</span></span>
</figcaption>
</figure>
<p>Further, in the hot and humid conditions of Northern Australia, it has been reported that workers may have removed protective gloves <a href="http://classic.austlii.edu.au/au/journals/PrecedentAULA/2005/56.pdf">to avoid sweating</a>. Again, research is needed to determine the implication of these practices for human health. </p>
<p>To this end, <a href="https://www.mercury-australia.com.au/">Mercury Australia</a>, a multi-disciplinary network of researchers, has formed to address the environmental, health and other issues surrounding mercury use, both contemporary and historical.</p>
<h2>Australia is yet to ratify</h2>
<p>The <a href="http://www.mercuryconvention.org/">Minamata Convention on Mercury</a> is a global treaty to control mercury use and release into the environment. Australia signed onto the convention in 2013 but is yet to ratify it. </p>
<p>Until the treaty is ratified, Australia is not legally bound to its obligations. It also places us at odds with <a href="http://www.mercuryconvention.org/Countries/Parties/tabid/3428/language/en-US/Default.aspx">more than 100 countries that have ratified it</a>, including many of Australia’s developed-nation counterparts.</p>
<p>Australia’s outlier status in this area is shown in the below table:</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=156&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=156&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=156&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=196&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=196&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342940/original/file-20200619-70371-1031289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=196&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Accession, acceptance or ratification have the same legal effect, where parties follow legal obligations under international law.</span>
</figcaption>
</figure>
<p>Mercury-based pesticide use was one of Australia’s largest sources of mercury emissions. But if Australia ratifies the convention, it would <a href="https://www.environment.gov.au/system/files/resources/c350c1c3-a14f-4bde-acfc-267bfd49f6e9/files/minamata-convention-mercury-pesticides-factsheet.pdf">be required to</a> control other sources of mercury emissions, such as <a href="https://www.environment.gov.au/protection/publications/minamata-convention-mercury-dental-fs">dental amalgam</a> and the <a href="http://www.mercuryconvention.org/Portals/11/documents/publications/BAT_BEP_E_interractif.pdf">burning of coal in power stations</a>.</p>
<p>The three active power stations in the Latrobe Valley, for example, together emit <a href="http://www.npi.gov.au/npidata/action/load/facility-source-result/criteria/lga/432/destination/ALL/source-type/ALL/substance-name/All/subthreshold-data/Yes/year/2019?pageIndex=1&sort=regBusinessName&dir=asc&pageSize=10">about 1,200 kilograms of mercury each year</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=362&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=362&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=362&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=455&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=455&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342925/original/file-20200619-70420-9prsae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=455&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The coal-burning Mount Piper Power station near Lithgow in NSW. Government efforts to reduce mercury emissions should focus on coal plants.</span>
<span class="attribution"><span class="source">David Gray/Reuters</span></span>
</figcaption>
</figure>
<h2>Time to look at coal</h2>
<p>If Australia ratified the Minamata Convention, it would provide impetus for a timely review and, if necessary, update of mercury regulations across Australia.</p>
<p>Emissions from coal-fired power stations in Australia are regulated by the states through pollution control licences. Some states would likely have to amend these licences if Australia ratified the convention. For example, Victorian licences for coal-fired power stations currently do not include <a href="https://www.dea.org.au/wp-content/uploads/2018/02/VIC-Brown-coal-fired-power-stations-licence-reviews-submission---02-18.pdf">limits on mercury emissions</a>. </p>
<p>Pollution control technologies were introduced at Australian coal plants in the early 1990s. But they <a href="https://www.theguardian.com/environment/2017/aug/15/australian-coal-power-pollution-would-be-illegal-in-us-europe-and-china-report">do not match state-of-the-art technologies applied to coal plants in North America and Europe</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-wont-australia-ratify-an-international-deal-to-cut-mercury-pollution-68820">Why won't Australia ratify an international deal to cut mercury pollution?</a>
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<p>Australian environment authorities have been <a href="https://www.environment.gov.au/protection/chemicals-management/mercury">examining the implications</a> of ratifying the convention. But progress is slow.</p>
<p>The issue of mercury emissions does not attract significant public or political attention. But there is a <a href="https://www.unenvironment.org/resources/publication/global-mercury-assessment-2018">global scientific consensus</a> that coordinated international action is needed.</p>
<p>The <a href="https://apvma.gov.au/sites/default/files/gazette_16062020.pdf">pesticide phase-out</a> and ban is an important step. But Australia still has a way to go.</p><img src="https://counter.theconversation.com/content/140596/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Larissa Schneider receives funding from the Australian Research Council. She is member of the Mercury Australia research network. </span></em></p><p class="fine-print"><em><span>Cameron Holley receives funding from the Australian Research Council. He is a member of the Mercury Australia research network.</span></em></p><p class="fine-print"><em><span>Darren Sinclair receives funding receives funding from the Australian Research Council. He is a member of the Mercury Australia research network.</span></em></p><p class="fine-print"><em><span>Simon Haberle receives funding from the Australian Research Council. He is member of the Mercury Australia research network.</span></em></p>Australia has failed to ratify an international treaty to reduce harmful mercury emissions. Mercury exposure can cause kidney damage and brain impairment, especially in children.Larissa Schneider, DECRA fellow, Australian National UniversityCameron Holley, Professor, UNSW SydneyDarren Sinclair, Professor, University of CanberraSimon Haberle, Professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1372782020-06-10T19:52:37Z2020-06-10T19:52:37ZMore than 1,200 tonnes of microplastics are dumped into Aussie farmland every year from wastewater sludge<figure><img src="https://images.theconversation.com/files/340804/original/file-20200610-82616-cy66ye.jpg?ixlib=rb-1.1.0&rect=21%2C56%2C4725%2C3102&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Every year, treated wastewater sludge called “biosolids” is recycled and spread over agricultural land. My recent research discovered this practice dumps <a href="https://www.sciencedirect.com/science/article/pii/S0956053X20301847?dgcid=author">thousands of tonnes of microplastics</a> into <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b04140">farmlands around the world</a>. In Australia, we estimate this amount as at least 1,241 tonnes per year. </p>
<p>Microplastics in soils can <a href="https://www.ncbi.nlm.nih.gov/pubmed/26852875">threaten</a> land, freshwater and marine <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b04048">ecosystems</a> by changing what they eat and their habitats. This causes some organisms to lose weight and have higher death rates.</p>
<p>But this is only the beginning of the problem. Microplastics are good at absorbing <a href="https://www.ncbi.nlm.nih.gov/pubmed/29448201">other pollutants</a> – such as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0043135418304068">cadmium, lead and nickel</a> – and can transfer these heavy metals to soils.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=346&fit=crop&dpr=1 600w, https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=346&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=346&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=434&fit=crop&dpr=1 754w, https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=434&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/340816/original/file-20200610-82616-rgxovs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=434&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wastewater treatment plants create biosolids, which are packed full of microplastics and toxic chemicals.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>And while microplastics alone is an enormous issue, other contaminants have also been found in biosolids used for agriculture. This includes <a href="https://www.sciencedirect.com/science/article/abs/pii/S030438941530090X">pharmaceutical</a> chemicals, personal care products, pesticides and herbicides, surfactants (chemicals used in detergents) and flame retardants. </p>
<p>We must stop using biosolids for farmlands immediately, especially when alternative ways to recycle wastewater sludge already exist.</p>
<h2>Where do the microplastics come from?</h2>
<p><a href="https://www.biosolids.com.au/info/what-are-biosolids/">Biosolids</a> are mainly a mix of water and organic materials. </p>
<p>But many household items that <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b04048">contain microplastics</a> – such as lotions, soaps, facial and body washes, and toothpaste – end up in wastewater, too. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0043135418304068">Other major sources of microplastics</a> in wastewater are synthetic fibres from clothing, plastics in the manufacturing and processing industries, and the breakdown of larger plastic debris. </p>
<p><iframe id="F0Qxi" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/F0Qxi/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Before they’re taken to farmlands, <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b04140">wastewater collection</a> systems carry all, or most, of these microplastics and other chemicals from residential, commercial and industrial sources to wastewater treatment plants.</p>
<p>To determine the weight of microplastics in Australia and other countries, my data analysis used the average minimum and maximum numbers of microplastics particles, per kilogram of biosolids samples, found in Germany, Ireland and the USA. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-have-no-idea-how-much-microplastic-is-in-australias-soil-but-it-could-be-a-lot-96858">We have no idea how much microplastic is in Australia's soil (but it could be a lot)</a>
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<hr>
<p><a href="https://www.biosolids.com.au/guidelines/australian-biosolids-statistics/">Australia</a> produced 371,000 tonnes of biosolids in 2019. And globally, we estimate between 50 to more than 100 million tonnes of biosolids are produced each year.</p>
<h2>Why microplastics are harmful</h2>
<p>Microplastics in soil can <a href="https://link.springer.com/article/10.1007/s11157-018-9480-3">accumulate in the food web</a>. This happens when organisms consume more microplastics than they lose. This means heavy metals attached to the microplastics in soil organisms can progress further up the food chain, increasing the risk of human exposure to toxic heavy metals.</p>
<p>When microplastics accumulate heavy metals, they transfer these contaminants to plants and crops, such as rice and grains, as biosolids are spread over farmland. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-a-storm-microplastics-in-sydneys-cooks-river-increased-40-fold-139043">After a storm, microplastics in Sydney's Cooks River increased 40 fold</a>
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<p>Over time, microplastics break down and become even tinier, creating nanoplastics. Crops have also been shown to absorb nanoplastics and move them to different plant tissues. </p>
<p>Our research results also show that after the wastewater treatment process, the absorption potential of microplastics for metals increases. </p>
<p>The metal cadmium, for example, is particularly susceptible to microplastics in biosolids and can be transported to plant cells. Research from 2018 showed microplastics in biosolids can <a href="https://www.sciencedirect.com/science/article/abs/pii/S0043135418304068">absorb cadmium</a> ten times more than virgin microplastics (new microplastics that haven’t gone through wastewater treatment). </p>
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<h2>Biosolids have a cocktail of nasty chemicals</h2>
<p>It’s not just plastic – many industrial additives and <a href="https://www.sciencedirect.com/science/article/abs/pii/S030438941530090X">chemicals</a> have been found in wastewater and biosolids. </p>
<p>This means they may accumulate in soils and affect the equilibrium of biological systems, with negative effects on plant growth. For example, researchers have found pharmaceutical chemicals in particular can reduce plant growth and inhibit root elongation.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sustainable-shopping-how-to-stop-your-bathers-flooding-the-oceans-with-plastic-92660">Sustainable shopping: how to stop your bathers flooding the oceans with plastic</a>
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<p>Other chemical contaminants – such as <a href="https://www.epa.gov/pfas/what-are-pfcs-and-how-do-they-relate-and-polyfluoroalkyl-substances-pfass">PFCs</a>, <a href="https://www.epa.gov/pfas/basic-information-pfas">PFAS</a> and <a href="https://www.foodstandards.gov.au/consumer/chemicals/bpa/Pages/default.aspx">BPA</a> – have likewise been detected in biosolids.</p>
<p>The effects these chemicals have on plants may lead to problems further down the food chain, such as humans and other animals inadvertently consuming pharmaceuticals and harmful chemicals.</p>
<h2>What can we do about it?</h2>
<p>Given the cocktail of toxic chemicals, heavy metals and microplastics, using biosolids in agricultural soils must be stopped without delay.</p>
<p>The good news is there’s another way we can recycle the world’s biosolids: turning them into <a href="https://www.mdpi.com/2075-5309/9/1/14">sustainable fired-clay bricks</a>, called “bio-bricks”. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/340813/original/file-20200610-82645-z5f6jk.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">Bricks incorporated with biosolids are a sustainable solution to an environmental problem.</span>
<span class="attribution"><span class="source">RMIT media</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>My team’s research from last year found bio-bricks a <a href="https://www.rmit.edu.au/news/media-releases-and-expert-comments/2019/jan/recycling-biosolids-sustainable-bricks">sustainable solution</a> for both the wastewater treatment and brick manufacturing industries. </p>
<p>If 7% of all fired-clay bricks were biosolids, it would redirect all biosolids produced and stockpiled worldwide annually, including the millions of tonnes that currently end up in farmland each year. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/youre-eating-microplastics-in-ways-you-dont-even-realise-97649">You're eating microplastics in ways you don't even realise</a>
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<p><a href="https://www.mdpi.com/2075-5309/9/1/14">We also found</a> they’d be more energy efficient. The properties of these bio-bricks are very similar to standard bricks, but generally requires 12.5% less energy to make.</p>
<p>And generally, comprehensive <a href="https://ascelibrary.org/doi/abs/10.1061/(ASCE)MT.1943-5533.0002308">life-cycle assessment</a> has shown biosolid bricks are more environmentally friendly than conventional bricks. These bricks will reduce or eliminate a <a href="https://www.sciencedirect.com/science/article/pii/S0301479714002047">significant source of greenhouse gas emissions from biosolids stockpiles</a> and will save some virgin resources, such as clay soil and water, for the brick industry. </p>
<p>Now, it’s up to the agriculture, wastewater and brick industries, and governments to make this important transition.</p><img src="https://counter.theconversation.com/content/137278/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abbas Mohajerani received funding from Melbourne Water for previous, related research on biosolid incorporated bricks. </span></em></p>We must stop using biosolids for farmlands immediately, especially when alternative ways to recycle wastewater sludge already exist.Abbas Mohajerani, Associate Professor, School of Engineering, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1307702020-02-24T13:47:51Z2020-02-24T13:47:51ZMine waste dams threaten the environment, even when they don’t fail<figure><img src="https://images.theconversation.com/files/316523/original/file-20200220-92533-1j44n5r.jpg?ixlib=rb-1.1.0&rect=52%2C22%2C4813%2C3141&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The January 2019 collapse of a dam in Brumadinho, Brazil, sent mining tailings and mud over the landscape for miles, destroying this bridge and killing 300 people. </span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Brazil-Dam-Collapse/50a79aefb36f41f99e4c1efeb80df7a1/178/0">Andre Penner/AP</a></span></figcaption></figure><p>Scars from large mining operations are permanently etched across the landscapes of the world. The <a href="https://doi.org/10.1038/s41893-018-0048-6">environmental damage</a> and <a href="https://theconversation.com/dam-collapse-at-brazilian-mine-exposes-grave-safety-problems-110666">human health hazards</a> that these activities create may be both <a href="https://theconversation.com/mining-powers-modern-life-but-can-leave-scarred-lands-and-polluted-waters-behind-119453">severe and irreversible</a>. </p>
<p>Many mining operations store enormous quantities of waste, known as tailings, onsite. After miners excavate rock, a processing plant crushes it to recover valuable minerals such as gold or copper. The leftover pulverized rock and liquid slurry become tailings, which often are acidic and contain high concentrations of arsenic, mercury and other toxic substances. </p>
<p>Mining companies store tailings forever, frequently behind earth-filled embankment dams. Over the past 100 years, <a href="https://doi.org/10.1155/2019/4159306">more than 300 mine tailing dams worldwide have failed</a>, mainly due to <a href="https://doi.org/10.1155/2019/4159306">foundation weakening, seepage, overtopping and earthquake damage</a>.</p>
<p>We are <a href="https://depts.washington.edu/oldenlab/">research scientists</a> studying <a href="https://flbs.umt.edu/newflbs/about-flbs/people/page-elements/flbs-people/people/chris-sergeant/">how humans affect rivers</a>. In our view, the damage caused by stored mine waste often outweighs the benefits that mining provides to local economies and the technology industry. </p>
<p>This issue is especially urgent now in a region of the Pacific Northwest where Alaska and British Columbia meet. This zone, known as the <a href="https://www.visualcapitalist.com/story-golden-triangle-british-columbia/">Golden Triangle</a>, is studded with mineral claims and leases. We believe that rivers in this area could be severely damaged if proposed mega-projects are allowed to proceed.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VYYwzAvQIF8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Footage of the Mt. Polley tailing spill in Canada.</span></figcaption>
</figure>
<h2>Catastrophic failures renew old worries</h2>
<p>Tailings dam failures range from the 1966 <a href="https://www.bbc.co.uk/news/resources/idt-150d11df-c541-44a9-9332-560a19828c47">Aberfan disaster</a> that buried a Welsh village to multiple spills over the past decade in <a href="https://news.mongabay.com/2017/12/mine-tailings-dam-failures-major-cause-of-environmental-disasters-report/">Canada, China, Chile and the United States</a>. The <a href="https://www.icold-cigb.org/">International Commission on Large Dams</a>, a nongovernmental organization, warned in 2001 that the frequency and severity of tailings dam failures was <a href="http://www.unep.fr/shared/publications/pdf/2891-TailingsDams.pdf">increasing globally</a>. </p>
<p>Two catastrophic and highly publicized failures at the <a href="https://www.mountpolleyreviewpanel.ca/">Mt. Polley dam in Canada</a> in 2014 and the <a href="https://theconversation.com/dam-collapse-at-brazilian-mine-exposes-grave-safety-problems-110666">Brumadinho dam in Brazil</a> in 2019 finally catalyzed a response. The <a href="https://www.icmm.com/">International Council on Mining and Metals</a>, the <a href="https://www.unenvironment.org/">United Nations Environment Programme</a> and the independent organization <a href="https://www.unpri.org/">Principles for Responsible Investment</a> drafted a “global standard for the safe and secure <a href="https://globaltailingsreview.org/">management of mine tailings facilities</a>.” The first public review of the standard was completed in December 2019, and its authors plan to finalize their recommendations by the end of March 2020.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/316684/original/file-20200222-92518-hl8w9w.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">Crews and a sniffer dog search for buried bodies 99 days after the Jan. 25, 2019 collapse of the Corrego do Feijao mining dam in Brumadinho, Brazil.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sniffer-dog-locates-body-parts-as-emergency-crews-continue-news-photo/1140958907?adppopup=true">Douglas Magno/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>The standard aspires to achieve “zero harm to people and the environment and zero tolerance for human fatality.” Reducing the likelihood of future dam failures and minimizing damage if one does break are appropriate goals, but our research suggests that the concept of “zero harm” is false and potentially dangerous.</p>
<p>Why? Because once in place, tailings dams and their toxic reservoirs require maintenance forever. Even if there is no catastrophic failure, these dams and their surrounding infrastructure can cause ecological harm in multiple ways. They require artificial water diversions and releases, which upset natural flow patterns in surrounding streams and modify water temperature and concentrations of metals. And polluted groundwater seepage from unlined reservoirs or failing liners is often hard to detect and treat. </p>
<p>These ecosystem modifications directly affect organisms on land and in the water downstream. Every decision to allow a mine to proceed with a tailings storage facility indelibly transforms rivers and their ecosystems for hundreds to thousands of years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/316658/original/file-20200221-92533-idvzfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mining dominates the Iskut River area of British Columbia. Each red segment represents a separate mining claim.</span>
<span class="attribution"><a class="source" href="https://reformbcmining.ca/maps/">BC Mining Law Reform</a></span>
</figcaption>
</figure>
<h2>International rivers at risk</h2>
<p>Today these decisions loom large in the Golden Triangle, home to the Taku, Stikine and Unuk Rivers – three of the <a href="https://doi.org/10.1038/s41586-019-1111-9">longest undammed rivers in North America</a>. Salmon from these rivers have supported indigenous communities for millennia, generate <a href="https://www.mcdowellgroup.net/wp-content/uploads/2016/10/FINAL-Southeast-Alaska-Transboundary-Watershed-Economic-Impacts-10_10red.pdf">tens of millions of dollars in economic activity annually</a> and provide a dependable source of food for organisms ranging from insects to brown bears.</p>
<p>We calculate that 19% of the total drainage area of these three rivers is staked with mineral mining claims or leases. This includes 59% of the Unuk River watershed, along with the entire Iskut River corridor, the largest tributary to the Stikine River. </p>
<p>We have identified <a href="https://docs.google.com/spreadsheets/d/1ipseXInQJTFPt1wtac431c9AEmDHJqb05qqRwFTOlNU/edit#gid=0">dozens of mines in exploratory or production phases</a>. Some industry representatives call these statistics irrelevant because only a small portion of the claims will convert to economically viable projects. But from our perspective, the fact that vast areas of these watersheds are included in initial explorations implies that few rivers in this region are safe from potential mining development.</p>
<p>Most proposed projects in the Golden Triangle will require open pit mining and tailings storage. As one indicator of their potential scale, the <a href="https://earthengine.google.com/timelapse#v=57.72808,-129.82688,10.301,latLng&t=3.43&ps=50&bt=19840101&et=20181231&startDwell=0&endDwell=0">Red Chris Mine</a>, which has operated since 2015 in the headwaters of the Stikine River, maintains a tailings reservoir dam that is permitted to ultimately stand 344 feet (105 meters) high and contain approximately 107 billion cubic feet (305 million cubic meters) of tailings. The heights of the failed dams at Mt. Polley and Brumadinho were 131 feet (40 meters) and 282 feet (86 meters), respectively. </p>
<p>Those heights pale in comparison to dams proposed for three metal mines in the Stikine and Unuk watersheds, including KSM, Galore Creek, and Schaft Creek. The tallest of four dams <a href="https://www.miningdataonline.com/reports/KSM_PFS_PEA_112016.pdf">planned for KSM</a> would measure 784 feet (239 meters) – one of the highest dams in North America, and the second highest in Canada. </p>
<p>At KSM, economically viable ore will be transported from open pits to a processing facility and tailings storage reservoir, accessed via twin tunnels built under a glacier. After what the project proponent calls the 53-year “life of mine,” Seabridge Gold proposes to treat runoff water from the piled waste rock <a href="https://www.miningdataonline.com/reports/KSM_PFS_PEA_112016.pdf">for at least 200 years</a>. </p>
<p>Each component of these proposed mines is an incredible engineering feat that will cost billions of dollars to construct and more to clean up later. From the perspective of maintaining an ecologically healthy watershed, the life of the mine is just beginning when operations close. </p>
<p>In contrast to more conventional water storage dams, which are licensed and built for a finite operating life, tailings dams must hold back their slurry forever. The likelihood of leaks or dam failure compounds over this multigenerational time period as facilities age and projects no longer generate revenue. </p>
<h2>Accurately assessing risk</h2>
<p>Rivers are the arteries of coastal Alaska and northwestern Canada, draining pristine snow and ice-covered mountains and pumping out cold, clean water to support fish, wildlife and people. Here and elsewhere, we believe that regulators should take a measured and cautious view of current and planned tailings facilities. </p>
<p>Dam failures are <a href="https://doi.org/10.3390/environments4040075">increasing in frequency</a>, and often are so large that true cleanup or reclamation is not possible. Before more are built, we see a need for independent science to provide a means of honestly assessing the risk of storing mining waste.</p>
<p>[<em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>.]</p><img src="https://counter.theconversation.com/content/130770/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Sergeant receives funding from Wilburforce Foundation.</span></em></p><p class="fine-print"><em><span>Julian D. Olden 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>Dams built to hold enormous quantities of toxic mining waste have a long history of spills. Decisions in the Pacific Northwest threaten three free-flowing rivers there.Christopher Sergeant, Research Scientist, Flathead Lake Biological Station, University of MontanaJulian D. Olden, Professor of Aquatic and Fishery Sciences, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1310212020-02-14T22:23:36Z2020-02-14T22:23:36ZNatural supplements can be dangerously contaminated, or not even have the specified ingredients<figure><img src="https://images.theconversation.com/files/313463/original/file-20200204-41476-1i8r1r2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some supplement products contain substances that are harmful.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/various-pills-lying-on-a-white-surface-royalty-free-image/483106863?adppopup=true">Getty Images / David Malan</a></span></figcaption></figure><p>More than two-thirds of Americans take dietary supplements. The vast majority of consumers – 84% – <a href="https://www.crnusa.org/CRN-consumersurvey-archives/2015/">are confident</a> the products are safe and effective.</p>
<p>They should not be so trusting.</p>
<p><a href="https://scholar.google.com/citations?user=lWAD9d8AAAAJ&hl=en">I’m</a> a professor of pharmacy practice at the University of Connecticut. As described in <a href="https://doi.org/10.1177/1060028019900504">my new article</a> in the Annals of Pharmacotherapy, consumers take real risks if they use diet supplements not independently verified by reputable outside labs. </p>
<h2>What are the risks?</h2>
<p>Heavy metals, which are known to cause <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4427717/">cancer, dementia and brittle bones</a>, contaminate many diet supplements. <a href="https://doi.org/10.1371/journal.pone.0049676">One study of 121 products</a> revealed 5% of them surpassed the safe daily consumption limit for arsenic. Two percent had excess lead, cadmium and aluminum; and 1% had too much mercury. <a href="https://www.fda.gov/food/dietary-supplement-products-ingredients/fda-advises-consumers-stop-using-certain-life-rising-dietary-supplements">In June 2019</a>, the Food and Drug Administration seized 300,000 dietary supplement bottles because their pills contained excessive lead levels.</p>
<p>Bacterial and fungal contamination in dietary supplements <a href="https://www.foodsafetynews.com/2014/08/dietary-supplements-recalled-for-possible-salmonella-contamination/">is not uncommon</a>. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1745-4565.2009.00167.x">In one assessment</a>, researchers found bacteria in all 138 products they investigated. Toxic fungi were also in many of the supplements, and counts for numerous products exceeded the acceptable limits set by the <a href="https://www.usp.org/">United States Pharmacopeia</a>. Fungal contamination of diet supplements <a href="https://www.liebertpub.com/doi/10.1089/fpd.2015.2108">has been linked</a> to serious liver, intestinal and appendix damage. </p>
<p>From 2017-18, <a href="https://www.fda.gov/food/outbreaks-foodborne-illness/fda-investigated-multistate-outbreak-salmonella-infections-linked-products-reported-contain-kratom">dozens were hospitalized</a> with salmonella poisoning after ingesting kratom, a highly addictive natural opioid. Thirty-seven of the kratom products studied were contaminated. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313468/original/file-20200204-41527-11izspw.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">There are ways consumers can verify the quality and safety of supplements.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-asian-man-shopping-for-natural-medicine-royalty-free-image/81714441?adppopup=true">Getty Images / Tanya Constantine</a></span>
</figcaption>
</figure>
<p>Some dietary supplements contain drugs, yet the manufacturers <a href="https://theconversation.com/beware-of-natural-supplements-for-sex-gain-and-weight-loss-106484">don’t disclose that information</a> to consumers. Frequently, the concealed drugs are experimental and, in some cases, removed from the market because they’re dangerous. Hundreds of weight-loss, sexual-dysfunction and muscle-building products are adulterated with inferior or harmful substances.</p>
<p>Sometimes, the herb you think you’re buying contains little to no active ingredient. Occasionally, another herb is substituted. </p>
<p>The consequences for consumers are considerable. When manufacturers replaced the herb <a href="https://www.nejm.org/doi/full/10.1056/NEJM200006083422301">Stephania tetrandra with the herb Aristolochia fangchi</a> in 2000, more than 100 patients developed severe kidney damage; 18 more got kidney or bladder cancer. Although the herb is now banned by the U.S., <a href="https://www.tandfonline.com/doi/full/10.1080/19440049.2014.892215?src=recsys">a 2014 investigation</a> found Aristolochia fangchi in 20% of the Chinese herbal products sold on the internet. </p>
<p><a href="https://doi.org/10.1002/jcph.1387">In an assessment</a> of CBD products, only 12.5% of vaporization liquids, 25% of tinctures and 45% of oils contained the promised amount of CBD. In most cases they held far less. A few CBD products had enough THC to put the user in legal jeopardy of marijuana possession.</p>
<p>Embarrassed by a New York Attorney General’s Office <a href="http://www.documentcloud.org/documents/1532311-supplements.html#document/p1">investigation</a> suggesting widespread and fraudulent under-dosing of active ingredients in dietary supplements, <a href="https://cvshealth.com/newsroom/press-releases/cvs-pharmacy-launches-tested-be-trusted-program-vitamins-and-supplements">CVS pharmacies analyzed</a> 1,400 products that it previously sold in its stores. <a href="https://cvshealth.com/newsroom/press-releases/cvs-pharmacy-launches-tested-be-trusted-program-vitamins-and-supplements">Seven percent,</a> or about 100 products, failed, resulting in updates to the supplement facts panel or removal of the product from shelves. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313467/original/file-20200204-41476-b4qlq3.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">It can be difficult for the FDA to adequately oversee supplements.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/FDA-Smokeless-Tobacco/a7af1c510e574d73917d69703d24c31e/195/0">Associated Press / Andrew Harnik</a></span>
</figcaption>
</figure>
<h2>What should consumers do?</h2>
<p>The <a href="https://ods.od.nih.gov/About/DSHEA_Wording.aspx">Dietary Supplement Health and Education Act</a> of 1994 allows manufacturers to sell dietary supplements without providing proof of their quality to the FDA. Instead, it’s up to the FDA to prove a product is unsafe and take it off the market. That’s an incredibly tall order, and woefully inadequate. But it’s unlikely to change.</p>
<p>In the meantime, I recommend that consumers should not purchase supplements without verification from one of three highly regarded independent laboratories: the aforementioned United States Pharmacopeia, NSF International and ConsumerLabs.com. The United States Pharmacopeia is an organization that <a href="https://www.usp.org/dietary-supplements-herbal-medicines">sets reference and quality standards</a> for prescription medication and food in the U.S.; the NSF International is an independent group that assesses safety and risk for food, water and consumer products; and ConsumerLabs.com is a company started to verify product quality for consumers that are paying members. These laboratories conduct an <a href="https://www.consumerreports.org/supplements/how-to-choose-supplements-wisely/">initial analysis</a> and then perform periodic unannounced assessments of the products; those with the appropriate amount of active ingredient, and without contamination or adulteration, can put the United States Pharmacopeia, NSF and <a href="https://www.consumerlab.com/seal.asp">ConsumerLabs.com seals</a> on their bottles. CVS announced that all products sold at its stores going forward will need to provide the company proof of quality. Other major retailers should follow suit.</p>
<p>Some manufacturers conduct quality testing and post certificates of analysis on their websites. But the autonomy of the laboratory, and its standards, <a href="https://www.consumerlab.com/answers/can-i-trust-supplement-manufacturer-lab-reports-and-certificates-of-analysis/certificates-of-analysis/">are often not known</a>. Sometimes, labs may select an inappropriate testing method, intentionally or unintentionally. Sometimes they perform the test incorrectly, or simply make up results.</p>
<p>Because the FDA can’t fully protect you from quality issues in dietary supplements – at least not right now – you must protect yourself. Even if a celebrity or “health guru” recommends a product, that doesn’t mean it’s high-quality. Before you put any supplement into your body, demand proof.</p>
<p><em>Editor’s Note: This article has been updated to state that NSF International, not the National Science Foundation, assesses safety and risk for food, water and consumer products.</em></p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/131021/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>C. Michael White 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>Americans love their supplements, but some of the products are contaminated with heavy metals, bacteria and toxic fungi. The FDA has little control because of a law passed in 1994.C. Michael White, Professor and Head of the Department of Pharmacy Practice, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1287762020-01-14T13:48:48Z2020-01-14T13:48:48ZMicrowaving sewage waste may make it safe to use as fertilizer on crops<figure><img src="https://images.theconversation.com/files/309125/original/file-20200108-107231-ence2y.jpg?ixlib=rb-1.1.0&rect=20%2C20%2C3395%2C2227&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Water purification at a modern urban wastewater treatment plant involves removing undesirable chemicals, suspended solids and gases from contaminated water. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/modern-urban-wastewater-treatment-plant-purification-530497726">arhendrix/Shutterstock.com</a></span></figcaption></figure><p>My team has discovered another use for microwave ovens that will surprise you.</p>
<p>Biosolids – primarily dead bacteria – from sewage plants are usually dumped into landfills. However, they are rich in nutrients and can potentially be used as fertilizers. But farmers can’t just replace the normal fertilizers they use on agricultural soil with these biosolids. The reason is that they are often contaminated with toxic heavy metals like arsenic, lead, mercury and cadmium from industry. But dumping them in the landfills is wasting precious resources. So, what is the solution?</p>
<p><a href="http://www.eng.fsu.edu/%7Egchen/">I’m an environmental engineer</a> and an expert in wastewater treatment. My colleagues and I have figured out how to treat these biosolids and remove heavy metals so that they can be safely used as a fertilizer. </p>
<h2>How treatment plants clean wastewater</h2>
<p>Wastewater contains organic waste such as proteins, carbohydrates, fats, oils and urea, which are derived from food and human waste we flush down in kitchen sinks and toilets. Inside treatment plants, bacteria decompose these organic materials, cleaning the water which is then discharged to rivers, lakes or oceans.</p>
<p>The bacteria don’t do the work for nothing. They benefit from this process by multiplying as they dine on human waste. Once water is removed from the waste, what remains is a solid lump of bacteria called biosolids. </p>
<p>This is complicated by the fact that wastewater treatment plants accept not only residential wastewater but also industrial wastewater, including the liquid that seeps out of solid waste in landfills – called leachate – which is contaminated with toxic metals including arsenic, lead, mercury and cadmium. During the wastewater treatment process, heavy metals are attracted to the bacteria and accumulate on their surfaces. </p>
<p>If farmers apply the biosolids at this stage, these metals will separate from the biosolids and contaminate the crop for human consumption. But removing heavy metals isn’t easy because the chemical bonds between heavy metals and biosolids are very strong. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309129/original/file-20200108-107249-x9uck3.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">Gang Chen microwaves some biosolids, separating the organic material from the toxic metals.</span>
<span class="attribution"><span class="source">Gang Chen/FAMU-FSU College of Engineering</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Microwaving waste releases heavy metals</h2>
<p>Conventionally, these metals are removed from biosolids using chemical methods involving acids, but this is costly and generates more dangerous waste. This has been practiced on a small scale in some agricultural fields.</p>
<p>After a careful calculation of the energy requirement to release the heavy metals from the attached bacteria, I searched around for all the possible energy sources that can provide just enough to break the bonds but not too much to destroy the nutrients in the biosolids. That’s when I serendipitously noticed the microwave oven in my home kitchen and began to wonder whether microwaving was the solution.</p>
<p>My team and I tested whether microwaving the biosolids would break the bonds between heavy metals and the bacterial cells. We discovered it was efficient and environmentally friendly. The work has been <a href="https://doi.org/10.1016/j.jclepro.2019.118342">published in the Journal of Cleaner Production</a>. This concept can be adapted to an industrial scale by using electromagnetic waves to produce the microwaves.</p>
<p>This is a solution that should be beneficial for many people. For instance, managers of wastewater treatment plants could potentially earn revenue by selling the biosolids instead of paying disposal fees for the material to be dumped to the landfills. </p>
<p>It is a better strategy for the environment because when biosolids are deposited in landfills, the heavy metals seep into landfill leachate, which is then treated in wastewater treatment plants. The heavy metals thus move between wastewater treatment plants and landfills in an endless loop. This research breaks this cycle by separating the heavy metals from biosolids and recovering them. Farmers would also benefit from cheap organic fertilizers that could replace the chemical synthetic ones, conserving valuable resources and protecting the ecosystem. </p>
<p>Is this the end? Not yet. So far we can only remove 50% of heavy metals but we hope to shift this to 80% with improved experimental designs. My team is currently conducting small laboratory and field experiments to explore whether our new strategy will work on a large scale. One lesson I would like to share with everyone: Be observant. For any problem, the solution may be just around you, in your home, your office, even in the appliances you are using. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309126/original/file-20200108-107204-16wqxhx.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">Biosolids after collection from a waste treatment facility.</span>
<span class="attribution"><span class="source">Gang Chen/FAMU-FSU College of Engineering</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>[ <em><a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=expertise">Expertise in your inbox. Sign up for The Conversation’s newsletter and get a digest of academic takes on today’s news, every day.</a></em> ]</p><img src="https://counter.theconversation.com/content/128776/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gang Chen receives funding from the Hinkley Center for Solid and Hazardous Waste Management. </span></em></p>The solids from wastewater plants are usually dumped into landfills because they are contaminated with heavy metals. Now there is a way to remove the metals so the waste can be used as fertilizer.Gang Chen, Professor of Civil & Environmental Engineering, FAMU-FSU College of EngineeringLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1289922019-12-22T10:53:01Z2019-12-22T10:53:01ZGreat Lakes waters at risk from buried contaminants and new threats<figure><img src="https://images.theconversation.com/files/308114/original/file-20191220-11951-164dj10.jpg?ixlib=rb-1.1.0&rect=40%2C13%2C1756%2C1180&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A harmful algal bloom in the western basin of Lake Erie in August 2017.</span> <span class="attribution"><span class="source">(NOAA/Aerial Associates Photography, Inc. by Zachary Haslick/flickr)</span></span></figcaption></figure><p>Nickle Beach, Copper Harbor, Silver Bay. These places, all situated on the shores of the Laurentian Great Lakes, evoke the legacy of mining connected with the region. </p>
<p>While mining operations for metal ores and their refining have all but ceased here, there are renewed concerns over the safety of our Great Lakes source waters. One only has to think back to the <a href="https://doi.org/10.5942/jawwa.2016.108.0195">2014 water crisis in Flint, Mich.</a> that exposed more than 100,000 people to elevated lead levels or to <a href="https://www.thestar.com/news/investigations/lead-in-water.html">more recent headlines</a> over lead contamination in water distributed from Canadian taps. </p>
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Read more:
<a href="https://theconversation.com/lead-tainted-water-how-to-keep-homes-schools-daycares-and-workplaces-safe-126815">Lead-tainted water: How to keep homes, schools, daycares and workplaces safe</a>
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<p>The Great Lakes basin is home to more than 35 million people distributed across two nations and numerous First Nations. They all rely on this resource for potable water, employment, sustenance and recreational opportunities. </p>
<p>Yet, environmental concerns are a recurring theme, compromising beneficial uses of the lakes and connecting rivers and posing a threat to a <a href="http://www.gsgp.org/media/1818/2016-cglslgp-bmo-economic-report.pdf">combined GDP of US$5.8 trillion across the region</a>. </p>
<p>Canadians have come to expect access to safe, clean and reliable drinking water, as well as access to lakes and rivers for recreational use. However, a legacy of natural resource extraction and industrial use, together with new pressures on freshwater ecosystems, challenge the integrity and sustainable use of these resources. </p>
<h2>An A grade, for now</h2>
<p>Clearly, past environmental crises like <a href="https://www.jstor.org/stable/25037121">mercury pollution of Lake St. Clair</a> in the 1970s, the <a href="https://doi.org/10.2166/wqrj.1986.038">St. Clair River’s blob of perchloroethylene (a dry-cleaning solvent)</a> in 1985, the <a href="https://doi.org/10.1080/152873902753338572">outbreak of gastroenteritis in Walkerton, Ont.</a> in 2000, the <a href="https://www.hrwc.org/our-watershed/threats/pfas-and-the-huron-river/">contamination of Michigan’s Huron River with PFAS (a family of persistent chemicals)</a> in 2017, and the Flint water crisis provide compelling evidence of the need to control contaminants at their source and avoid another tipping point.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308115/original/file-20191220-11929-1aw4ya0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People gather outside Flint, Mich., city hall in January 2016 to protest the governor’s handling of the city’s water crisis.</span>
<span class="attribution"><span class="source">Sean Proctor/The Flint Journal-MLive.com via AP</span></span>
</figcaption>
</figure>
<p>Most people who call Ontario home live within the watershed of one of our four Great Lakes: Superior, Huron, Erie and Ontario. Over 80 per cent of Ontarians receive their drinking water from the lakes. </p>
<p>Considering the high dependency within the province on the Great Lakes, we are fortunate that the protection of these source waters is a priority of Ontario’s <a href="https://www.ontario.ca/laws/statute/06c22">Clean Water Act</a>. The province, as recently as 2011, received an A grade in Canada’s <a href="https://www.ecojustice.ca/case/waterproof-monitoring-canadas-drinking-water/">drinking water report card</a> issued by the environmental law non-profit Ecojustice.</p>
<p>Ontario’s <a href="https://www.ontario.ca/page/source-protection">Source Water Protection Plan</a> began in 2004 on the heels of the tragedy in Walkerton. A total of 38 local plans are currently in place, covering 95 per cent of Ontario’s population. Each plan identifies and ranks the risk of land-use patterns, such as locations of waste disposal sites, and effluent threats, such as industrial waste and fertilizers, that could lead to microbial, chemical or radiological contamination.</p>
<p>While the province is doing a good job protecting our Great Lakes source waters to ensure the safety of our drinking water, will these programs continue to protect us into the future and can they address vulnerabilities particular to our Great Lakes? </p>
<h2>Heightened threat from climate change?</h2>
<p>While the remaining industrial activity on the Great Lakes is regulated, the lakes themselves contain reservoirs of legacy contaminants, mostly in their sediments, that are vulnerable to resuspension. Metals, including mercury, PCBs and other persistent organic compounds top the list of concern. <a href="https://doi.org/10.1016/j.jglr.2018.11.008">Resuspension is becoming more common under climate change</a> with high water levels, declining ice cover and increased frequency and intensity of major storm events. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308123/original/file-20191220-11891-gw3bbr.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 crowd of swimmers and boaters gather at the annual (unsanctioned) Jobbie Nooner boating party in Lake St. Clair, Mich., in June 2015.</span>
<span class="attribution"><span class="source">(U.S. Coast Guard/flickr)</span></span>
</figcaption>
</figure>
<p>In fact, the manifestations of climate change in the region may be placing our drinking water systems at risk from a myriad of threats. These concerns include <a href="https://doi.org/10.1016/j.envint.2018.04.011">antibiotic-resistant bacteria</a>, threats from emerging chemicals, increases in discharge from combined sewer overflows and enhanced agricultural runoff of fertilizers and manure, which are implicated in the massive <a href="https://doi.org/10.1016/j.hal.2016.01.003">harmful algal blooms that have plagued Lake Erie’s western basin</a> in recent decades.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/great-lakes-flooding-the-warning-signs-that-homes-must-be-moved-122697">Great Lakes flooding: The warning signs that homes must be moved</a>
</strong>
</em>
</p>
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<p>While Source Water Protection Plans provide sound tools for managing our watersheds, we must remain vigilant and develop better risk-based tools that consider legacy and emerging chemical threats especially as they relate to changes to <a href="https://theconversation.com/climate-change-is-driving-rapid-shifts-between-high-and-low-water-levels-on-the-great-lakes-118095">high Great Lakes water levels</a> and increasing intensity of storms. </p>
<p>For example, a sediment disturbance triggered by high winds or shipping accidents could be addressed in a manner similar to chemical spills, closing water intakes until the threat has subsided.</p>
<h2>Investing in our future</h2>
<p>And oversight must go beyond source waters: the renewed concerns in Canada over lead contamination of our drinking water have refocused attention on the need to invest in municipal infrastructure to help ensure a safe and secure water supply. </p>
<p>These investments need to consider old threats, such as replacing lead service lines and antiquated plumbing, coupled with new tools to address growing vulnerabilities related to increased storm-induced discharge events, nutrient remobilization and harmful algal blooms being produced under a changing climate.</p>
<p>The adage holds true — an ounce of prevention is worth a pound of cure! </p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/128992/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Michael Lee McKay receives funding from the Natural Sciences and Engineering Research Council of Canada and from Environment and Climate Change Canada. </span></em></p><p class="fine-print"><em><span>Joel Edward Gagnon receives funding from the Natural Sciences and Engineering Research Council of Canada. </span></em></p><p class="fine-print"><em><span>Ken G. Drouillard receives funding from Natural Sciences and Engineering Research Council of Canada, Environment and Climate Change Canada, Ontario Ministry of Environment, Conservation and Parks. He is affiliated with the Detroit River Canadian Clean-Up Steering Committee and Monitoring and Research Committee. </span></em></p><p class="fine-print"><em><span>John Hartig and Michael Siu 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>The Great Lakes contain reservoirs of legacy contaminants, mostly in their sediments, that are vulnerable to resuspension.Robert Michael McKay, Executive Director, Great Lakes Institute for Environmental Research, University of WindsorJoel Edward Gagnon, Professor and Director, School of the Environment, University of WindsorJohn Hartig, Visiting Scholar, Great Lakes Institute for Environmental Research, University of WindsorKen G. Drouillard, Professor, Great Lakes Institute for Environmental Research, University of WindsorMichael Siu, Vice-President, Research and Innovation, University of WindsorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1139812019-04-02T21:04:24Z2019-04-02T21:04:24ZHow clean is your city? Just ask the bees<figure><img src="https://images.theconversation.com/files/267155/original/file-20190402-177163-v9uujc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Honey can carry clues about where pollutants come from. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>There’s a good chance you live in a city — or will soon. According to estimates by the United Nations, two out of every three people will live in an urban area by 2050. </p>
<p>The environmental impact of such rapid urbanization is a global concern. Traditional methods of monitoring pollution such as soil and air sampling can be expensive and time consuming. </p>
<p>We need new tools to track heavy metals and other pollution. So, we came up with a novel approach — honey.</p>
<h2>A sweet beginning</h2>
<p>It all began with a question. Julia Common, the chief beekeeper at <a href="https://hivesforhumanity.com/">Hives for Humanity</a>, a Vancouver-based, non-profit organization of urban beekeepers, was asked repeatedly, “How clean is the honey from downtown Vancouver?”</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264950/original/file-20190320-93048-dmd0ff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sampling honey from hives to test for environmental pollutants.</span>
<span class="attribution"><span class="source">Kate Smith</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Hives for Humanity manages about 200 hives within Vancouver. They’re on rooftops in the bustling city centre, near city gardens, in residential back yards and on farms in Delta, one of British Columbia’s major agricultural hubs. The organization doesn’t only produce honey, they also manage several therapeutic beekeeping programs. </p>
<p>To help answer this question, Dr. Dominique Weis, the director of the <a href="http://pcigr.eos.ubc.ca/">Pacific Centre for Isotopic and Geochemical Research</a>, measured a suite of trace elements (including lead, titanium and cadmium and others) in some of the honey from Hives for Humanity. <a href="https://www.nature.com/articles/s41893-019-0243-0">The honey</a> was clean, well below the <a href="https://doi.org/10.1111/1541-4337.12182">worldwide average</a> for heavy metals like lead. </p>
<p>But when Weis started looking more closely at the data, she realized that the honey carried additional clues about where the metals came from — and could be linked to land use and human activity in the immediate vicinity of the hive.</p>
<h2>Bee-sourcing science</h2>
<p>When honeybees forage for pollen and nectar, they also pick up dust and other small particles, and carry it back to the hive where it is incorporated into the honey and other hive products. </p>
<p>Since bees rarely forage more than two to three kilometres from their hive, the honey provides a chemical snapshot of the environment surrounding the hive. This phenomenon has been exploited in a number of studies to assess not only the levels of certain metals in the environment, but also the <a href="http://science.sciencemag.org/content/358/6359/109">effects of pesticides</a> and the environmental impact of <a href="https://doi.org/10.1051/apido:2005043">nuclear fallout</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sKkEF1KdPM4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>Our study showed that honey collected from areas of higher urban density contains elevated levels of metals, including tin, lead, cadmium, copper and zinc. Antimony, for example, is elevated in honey from downtown Vancouver, relative to suburban and rural honey, presumably due to stop-and-go traffic, as antimony is a component in vehicle break pads. </p>
<p>Other batches of honey sampled from areas near the shipping port, showed higher levels of vanadium, which can be found in heavy fuel oils burned by large engines such as those on cargo ships. </p>
<p>Even though we could find these trace elements in the honey samples, the concentrations were too low to pose any health risk. An adult would have to eat more than 600 grams of Vancouver honey per day to exceed tolerable daily lead intake levels. </p>
<h2>Fingerprinting honey</h2>
<p>We also analysed the different forms of lead, called isotopes, found in the honey to see how land use influenced the type of lead found in the environment. This had been tried only once before, <a href="https://pubs.acs.org/doi/abs/10.1021/acs.est.7b04084">in Australia</a>. </p>
<p>Because each source of lead has a characteristic isotopic composition, this approach is a little like fingerprinting the lead. Honey from industrial or heavily populated sectors of the city has a different lead fingerprint than local, natural lead found, for example, in the rocks from the <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1002/ggge.20191">Garibaldi volcanic belt</a> or <a href="https://doi.org/10.1016/j.chemgeo.2014.05.028">sediment from the Fraser River</a>. That means that the lead observed in honey from downtown hives is likely the result of human activities. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267154/original/file-20190402-177178-10hjwml.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">Vanadium can be found in heavy fuel oils like those used by large cargo ships.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Overall, the chemical signature in honey from any sector of the city reflects a combination of the botanical offerings that surround the hive, as well as other pollution sources associated with land use: traffic, shipping, rail yards and agriculture. </p>
<h2>Monitoring change</h2>
<p>The honey paints a comprehensive picture of current trace metal distribution throughout Metro Vancouver. In the future, we can look for variations, as the city grows and changes over the next century. Cities are dynamic and experience constant shifts in land use, population growth, aging infrastructure and climate change (especially coastal cities). </p>
<p>Because honey bees live where humans live, the method could be used anywhere hives exist. This makes it possible for cities around the world to harness the power of the honeybee, even if they lack more traditional environmental monitoring infrastructure.</p>
<p>Urban gardening and urban beekeeping are rising in popularity, which makes projects like these all the more amenable to community participation. </p>
<p>The benefit of engaging the community in the scientific process is that everyone gains a deeper appreciation for their environment and local ecology. That, like the honey in Vancouver, is a sweet outcome!</p><img src="https://counter.theconversation.com/content/113981/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Smith receives funding from the Natural Sciences and Engineering Research Council of Canada, the Peter Wall Institute for Advanced Studies and the University of British Columbia. </span></em></p><p class="fine-print"><em><span>Diane Hanano receives funding from the University of British Columbia. </span></em></p><p class="fine-print"><em><span>Dominique Weis receives funding from the Natural Sciences and Engineering Research Council of Canada, the Peter Wall Institute for Advanced Studies, the University of British Columbia and the Canada Foundation for Innovation.</span></em></p>Urban pollutants are a health concern in growing cities. Scientists are turning to honey bees to help monitor contaminants in soil, water, air and plants.Kate E. Smith, PhD Candidate, University of British ColumbiaDiane Hanano, Research Manager, University of British ColumbiaDominique Weis, Professor, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/861042017-10-24T20:18:24Z2017-10-24T20:18:24ZCosmic alchemy: Colliding neutron stars show us how the universe creates gold<figure><img src="https://images.theconversation.com/files/191637/original/file-20171024-30571-frs0vu.jpg?ixlib=rb-1.1.0&rect=96%2C0%2C803%2C573&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Illustration of hot, dense, expanding cloud of debris stripped from the neutron stars just before they collided.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/12740">NASA's Goddard Space Flight Center/CI Lab</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>For thousands of years, humans have searched for a way to turn matter into gold. <a href="https://doi.org/10.1086/660139">Ancient alchemists</a> considered this precious metal to be the highest form of matter. As human knowledge advanced, the mystical aspects of alchemy gave way to the sciences we know today. And yet, with all our advances in science and technology, the origin story of gold remained unknown. Until now. </p>
<p>Finally, scientists know how the universe makes gold. Using our <a href="https://doi.org/10.3847/2041-8213/aa91c9">most advanced telescopes and detectors</a>, we’ve seen it created in the cosmic fire of the two colliding stars first detected by LIGO via the gravitational wave they emitted.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191658/original/file-20171024-30605-ei0pxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&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 electromagnetic radiation captured from GW170817 now confirms that elements heavier than iron are synthesized in the aftermath of neutron star collisions.</span>
<span class="attribution"><a class="source" href="https://www.caltech.edu/news/caltech-led-teams-strike-cosmic-gold-80074">Jennifer Johnson/SDSS</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Origins of our elements</h2>
<p>Scientists have been able to piece together where many of the elements of the periodic table come from. The Big Bang <a href="https://doi.org/10.1146/annurev.nucl.56.080805.140437">created hydrogen</a>, the lightest and most abundant element. As stars shine, they fuse hydrogen into heavier elements like carbon and oxygen, the elements of life. In their dying years, stars create the common metals – aluminum and iron – and blast them out into space in different types of <a href="https://doi.org/10.1146/annurev.astro.38.1.191">supernova</a> <a href="https://doi.org/10.1146/annurev-astro-082708-101737">explosions</a>.</p>
<p>For decades, scientists have theorized that these stellar explosions also explained the origin of the heaviest and most rare elements, like gold. But they were missing a piece of the story. It hinges on the object left behind by the death of a massive star: a neutron star. Neutron stars pack one-and-a-half times the mass of the sun into a ball only 10 miles across. A teaspoon of material from their surface would weigh 10 million tons.</p>
<p>Many stars in the universe are in binary systems – two stars bound by gravity and orbiting around each other (think Luke’s home planet’s suns in “Star Wars”). A pair of massive stars might eventually end their lives as a pair of neutron stars. The neutron stars orbit each other for hundreds of millions of years. But Einstein says that their dance cannot last forever. Eventually, they must collide.</p>
<h2>Massive collision, detected multiple ways</h2>
<p>On the morning of August 17, 2017, a ripple in space passed through our planet. It was detected by the LIGO and Virgo gravitational wave detectors. This cosmic disturbance came from a pair of city-sized neutron stars colliding at one third the speed of light. The <a href="https://doi.org/10.1103/PhysRevLett.119.161101">energy of this collision</a> surpassed any atom-smashing laboratory on Earth.</p>
<p>Hearing about the collision, astronomers around the world, <a href="http://kilonova.org/about.html">including</a> <a href="https://dabrown.expressions.syr.edu/">us</a>, jumped into action. Telescopes large and small scanned the patch of sky where the gravitational waves came from. Twelve hours later, three telescopes caught sight of a brand new star – called a kilonova – in a galaxy called NGC 4993, about 130 million light years from Earth.</p>
<p>Astronomers had captured the light from the cosmic fire of the colliding neutron stars. It was time to point the world’s biggest and best telescopes toward the new star to see the visible and infrared light from the collision’s aftermath. In Chile, the Gemini telescope swerved its large 26-foot mirror to the kilonova. NASA steered the Hubble to the same location.</p>
<figure>
<img src="http://kilonova.org/img/DECam_fading_kn_final.gif">
<figcaption><span class="caption">Movie of the visible light from the kilonova fading away in the galaxy NGC 4993, 130 million light years away from Earth.</span></figcaption>
</figure>
<p>Just like the embers of an intense campfire grow cold and dim, the afterglow of this cosmic fire quickly faded away. Within days the visible light faded away, leaving behind a warm infrared glow, which eventually disappeared as well. </p>
<h2>Observing the universe forging gold</h2>
<p>But in this fading light was encoded the answer to the age-old question of how gold is made.</p>
<p>Shine sunlight through a prism and you will see our sun’s spectrum – the colors of the rainbow spread from short wavelength blue light to long wavelength red light. This spectrum contains the fingerprints of the elements bound up and forged in the sun. Each element is marked by a unique fingerprint of lines in the spectrum, reflecting the different atomic structure.</p>
<p>The spectrum of the kilonova contained the fingerprints of the heaviest elements in the universe. Its light carried the telltale signature of the neutron-star material decaying into platinum, gold and other so-called <a href="https://en.wikipedia.org/wiki/R-process">“r-process” elements</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191689/original/file-20171024-30613-1iljobe.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">Visible and infrared spectrum of the kilonova. The broad peaks and valleys in the spectrum are the fingerprints of heavy element creation.</span>
<span class="attribution"><span class="source">Matt Nicholl</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>For the first time, humans had seen alchemy in action, the universe turning matter into gold. And not just a small amount: This one collision created at least 10 Earths’ worth of gold. You might be wearing some gold or platinum jewelry right now. Take a look at it. That metal was created in the atomic fire of a neutron star collision in our own galaxy billions of years ago – a collision just like the one seen on August 17.</p>
<p>And what of the gold produced in this collision? It will be blown out into the cosmos and mixed with dust and gas from its host galaxy. Perhaps one day it will form part of a new planet whose inhabitants will embark on a millennia-long quest to understand its origin.</p><img src="https://counter.theconversation.com/content/86104/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duncan Brown receives funding from the National Science Foundation and the Research Corporation for Science Advancement.</span></em></p><p class="fine-print"><em><span>Edo Berger receives funding from the National Science Foundation and NASA. </span></em></p>Until the recent observation of merging neutron stars, how the heaviest elements come to be was a mystery. But their fingerprints are all over this cosmic collision.Duncan Brown, Professor of Physics, Syracuse UniversityEdo Berger, Professor of Astronomy, Harvard UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/785292017-06-04T20:22:38Z2017-06-04T20:22:38ZHidden feather patterns tell the story of birds<figure><img src="https://images.theconversation.com/files/171553/original/file-20170531-23707-pmqw5h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Shown as bright orange and pink highlights under X-ray fluorescent light, birds incorporate metals like zinc and bromine into feathers as they grow. </span> <span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-017-01878-y">Nature Scientific Reports </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Shearwaters are migratory marine birds that travel in a figure-of-eight pattern between the coasts of Siberia and Japan to Tasmania. </p>
<p>Placing one of the undistinguished grey feathers from a shearwater into the brilliant light of the <a href="http://www.ansto.gov.au/Resources/TEDxSydney/CapabilitiesandInstruments/index.htm">X-ray fluorescence microscopy beam</a> reveals something unexpected. We see intricately patterned deposits of chemical elements that tell the story of how a feather grows. </p>
<p>Among other findings, the images show strikingly regular bands containing zinc. There are roughly the same number of bands as the estimated number of days of feather growth. </p>
<p>Different from simple <a href="https://www.jstor.org/stable/4081089?seq=1#page_scan_tab_contents">feather growth bars</a>, these patterns were not known before <a href="https://www.nature.com/articles/s41598-017-01878-y">our study</a>, published this month. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171542/original/file-20170530-23672-13khb0p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three breast feathers from three individual Streaked Shearwater birds (<em>Calonectris leucomelas</em>), scanned simultaneously in high resolution X-ray fluorescence microscopy. Regular banding of the element zinc can be seen along the length of the feathers.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-017-01878-y/figures/4">Nature Scientific Reports</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Like the annual growth rings of trees, birds’ feathers lay down growth bars during their moult. (Moulting is the process of shedding old feathers, making way for new ones to grow.)</p>
<p>While bars simply show growth, the patterns of chemical elements tell us about the bird’s life during the growth period of the feather. They can indicate environmental exposures in a bird population, perhaps before impacts such as illness and death are clear. </p>
<p>We think the zinc banding may be a natural diurnal (daily) time stamp locked up within the feather. If confirmed, it’s a finding that may be applicable for retrospective dating of the occurrence of stressful events – for example, the temporary exposure to environmental contaminants such as heavy metals – during the period when birds grow new feathers. </p>
<p>In addition to zinc, other elements detected in feathers include calcium, bromine, copper and iron, each with its own unique pattern of distribution. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171554/original/file-20170531-23653-1dcrxw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Photographic image [A] and high resolution X-ray fluorescence microscopy images [B-F] in a breast feather from a Flesh-footed Shearwater (<em>Ardenna carneipes</em>); [B] reconstructed Compton scatter (as a density measure) ; [C] calcium distribution; [D] bromium distribution; [E] copper distribution; [F] iron distribution;</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-017-01878-y">Nature Scientific Reports</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The team, including field researcher <a href="http://www.utas.edu.au/profiles/staff/imas/Jennifer-Lavers">Jennifer Lavers</a>, analysed feathers painstakingly sampled from remote locations in Japan, as well as Lord Howe Island and New South Wales, and complemented by feathers from the Australia Museum collection in Sydney. </p>
<p>The bulk of the work investigated feathers from three species of shearwaters who migrate more than 60,000km over open ocean each year, to and from their breeding areas.</p>
<p>Foraging across huge areas, shearwaters are important indicators of environmental health. As described by Nobel Laureate and author <a href="https://theconversation.com/peter-doherty-why-our-fine-feathered-friends-deserve-better-7504">Peter Doherty</a> in his book <a href="https://www.mup.com.au/items/118148">Sentinel Chickens</a>: </p>
<blockquote>
<p>Birds of all kinds are recruited by humans to help us interpret changes in our increasingly challenged and unpredictable world. These wonderful creatures continually sample the atmosphere, oceans, fields and forests, signalling toxic and environmental dangers that threaten all vertebrates.</p>
</blockquote>
<p>Studying the population health of our feathered fellow creatures might be translatable into early warning signs for humans.</p>
<p>Observed patterns of chemical elements are also useful in a more fundamental scientific sense, as they open a window onto the dynamics of how feathers grow. It’s an example of “topobiology”, a term that describes the complex growth and regulation processes that take place as a few stem cells develop into an organ or structure such as a feather. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=756&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=756&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=756&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=951&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=951&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171547/original/file-20170531-23672-7dc7zk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=951&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Models of pattern formation in feathers. The bands of zinc may be due to mixed stem cells known as ‘follicular cells’ growing feathers over a period of around 30 days [A], or regular systemic pulses of changed zinc concentration [B]</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-017-01878-y/figures/2">Nature Scientific Reports</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Developmental biology is usually studied under the highly controlled conditions of a laboratory experiment. However, the current study shows that sensitive markers of development and health can also be applied to samples collected in field studies. </p>
<p>The chemistry of feathers might become a tool for watching our environment.</p><img src="https://counter.theconversation.com/content/78529/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Banati 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>Ordinary grey bird feathers placed under X-ray fluorescence reveal beautiful patterns of elements like zinc, telling a story of feather growth and the environments the birds have experienced.Richard Banati, Chair professor, Australian Nuclear Science and Technology OrganisationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/728622017-02-21T03:48:17Z2017-02-21T03:48:17ZMount Isa contamination ‘within guidelines’ but residents told to clean their homes<figure><img src="https://images.theconversation.com/files/156541/original/image-20170213-23316-1is1w3a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Industrial emissions have blown across Mount Isa for decades.</span> <span class="attribution"><span class="source">Mark P. Taylor</span>, <span class="license">Author provided</span></span></figcaption></figure><p>After an 11-year wait, Mount Isa Mines has released the <a href="http://www.mountisamines.com.au/EN/sustainability/Documents/2_UQ_Lead%20Pathways%20Study%20Air%20Report%20-%20Executive%20Summary%20FINAL.pdf">official report</a> into the lead contamination that has blighted the city for decades. </p>
<p>The report, commissioned by the mine’s owner, Glencore, and produced by researchers at the University of Queensland, says that household dust contaminated by airborne lead from the mining and smelting operations is the dominant source of the city’s exposure. </p>
<p>In some aspects this marks an important shift in the industry’s acceptance of the problem. Yet the report goes on to argue that Mount Isa residents are nevertheless responsible for keeping themselves, their houses and their children free from dust, thus putting the onus back on them to avoid exposure to the contamination.</p>
<h2>A history of excuses</h2>
<p>This is the latest iteration in the decade-long evolution of Mount Isa Mines’ <a href="http://www.mountisamines.com.au/EN/Media/Media_Documents/STATEMENT%20REGARDING%20THE%20RELEASE%20OF%20THE%20200708%20NATIONAL%20POLLUTANT.pdf">arguments</a> rebutting research that linked the contamination to its mining and smelting operations.</p>
<p>Back in 2007, when owned by Xstrata, Mount Isa Mines <a href="http://www.abc.net.au/worldtoday/content/2007/s1876019.htm">stated</a> that the contamination was “naturally occurring”. We have previously termed this the “miner’s myth” – the idea that contamination surrounding a mine is a product of <a href="http://link.springer.com/article/10.1007/s10653-016-9804-6">natural geology and weathering rather than the mining activity itself</a>.</p>
<p>Before Mount Isa Mines was taken over by Glencore in 2013, the company <a href="http://www.mountisamines.com.au/EN/Publications/Mine_to_Market/M2M_2012-10.pdf">admitted</a> that Mount Isa was affected by “industrial mineralisation” (industry-speak for contamination from emissions), but also said that the contamination was partly due to <a href="http://www.mcarthurrivermine.com.au/EN/Publications/Sustainability%20Reports/XZI%20240_Sustainability%20Report_v6%201_low%20res%20web%20version.pdf">natural sources</a> in the city’s soils and rocks.</p>
<p>We and our colleagues have produced more than 20 studies documenting environmental contamination and its management in the Mount Isa region, dating back to 2005 when the Leichhardt River, which supplies drinking water to Mount Isa, was found to be <a href="http://crcleme.org.au/Pubs/Monographs/regolith2005/Taylor_%26_Hudson-Edwards.pdf">contaminated with lead and other metals</a>. Since then, we have detailed contamination in local <a href="http://www.sciencedirect.com/science/article/pii/S0269749107002163">sediments</a>, <a href="http://pubs.rsc.org/-/content/articlelanding/2011/em/c0em00396d#!divAbstract">water</a> and <a href="http://www.sciencedirect.com/science/article/pii/S0883292710000740">soils</a>, and used <a href="http://www.sciencedirect.com/science/article/pii/S0269749113002455">isotope fingerprinting</a> to pinpoint the likely source; none of this research was mentioned in the new report.</p>
<p>Despite the welcome admission that the company is indeed contaminating Mount Isa, the report caveats this by saying that the risk of direct inhalation of lead emitted into the air is low. It states that exposure arises mainly when children are exposed to lead-contaminated surfaces in their homes – chiefly carpets. For Mount Isa families, these comments do not fully encapsulate the real challenges they face in protecting themselves and their families. </p>
<h2>Passing the buck</h2>
<p>The report offers the <a href="http://www.mountisamines.com.au/EN/sustainability/Documents/3_Lead%20Pathways%20Study%20Air%20Report%20-%20Community%20Brochure%20FINAL.pdf">following advice</a> to residents attempting to keep their exposure as low as possible:</p>
<ul>
<li><p>keep a “clean home environment”</p></li>
<li><p>consider replacing carpets with timber or other hard floors, and clean them with phosphate-based agents</p></li>
<li><p>wash childrens’ hands frequently and before meals, and encourage very young children not to suck non-food items</p></li>
<li><p>wash all homegrown fruit and vegetables, and peel root vegetables, before cooking and/or eating.</p></li>
</ul>
<p>The implied argument is essentially that, despite the contamination, if you do the right thing (such as keeping your house clean) there is no problem.</p>
<p>The obvious rebuttal to this is that if there were no industrial lead in the community, there would be no problem at all. The root cause of the issue is not the natural hand-to-mouth behaviours of children but the pervasive, persistent and permanent arsenic, cadmium and lead contamination that penetrates everything they touch: clothes, toys, food, floors and furnishings.</p>
<p>The rates of lead dust <a href="http://www.sciencedirect.com/science/article/pii/S0883292710000740">deposition</a> are such that that people living closest to the smelters would have to wash their backyards and indoor surfaces several times a day to keep toxic dust levels within acceptable guidelines. Cleaning one’s house more than once a day, especially if working or looking after little children, is nearly impossible to maintain even over a few days, never mind a lifetime. While the advice to keep houses, hands and surfaces is not unreasonable in itself, the <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006047.pub5/abstract">evidence suggests</a> that it is little use in preventing lead exposure.</p>
<h2>How serious is the exposure?</h2>
<p>Mount Isa’s schoolchildren are performing well below the national average, according to <a href="https://www.aedc.gov.au/data/data-explorer?id=62279">standardised testing data</a> from the first full year of school. Similar outcomes have been seen in <a href="http://www.sciencedirect.com/science/article/pii/S0269749115300841">Broken Hill</a>, another of Australia’s major <a href="http://theconversation.com/australian-children-exposed-to-toxic-mining-metals-do-worse-at-school-48343">lead mining</a> towns. Children in North Mount Isa, the area nearest the smelter, did worse than in other areas of the city.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/157477/original/image-20170220-15894-rd4axz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Educational testing outcomes in children from various areas of Mount Isa, compared with the national average.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Mount Isa’s children have an average blood lead level of about <a href="http://www.leadalliance.com.au/wp-content/uploads/2016/09/MILHMC-Biennial-Report-2013-2016.pdf">35 parts per billion</a> – about three times <a href="https://www.cdc.gov/nchs/nhanes/">higher than normal</a>. A <a href="http://onlinelibrary.wiley.com/doi/10.1111/ajpy.12096/abstract">2015 study</a> of children from Broken Hill and Port Pirie showed that a increase in blood lead from 10 to 100 parts per billion can reduce IQ by 13.5 points. Relevantly, low exposures cause <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev-publhealth-031912-114413">proportionally more harm</a>, which is why it is important for children to be protected from any lead contamination at all.</p>
<p>The <a href="http://www.mountisamines.com.au/EN/sustainability/Documents/2_UQ_Lead%20Pathways%20Study%20Air%20Report%20-%20Executive%20Summary%20FINAL.pdf">report</a> is clear that exposure happens as a result of contamination released into the air, which later settles as dust:</p>
<blockquote>
<p>The major source of lead exposure is via ingestion in the community and is from air particulates (<250µm diameter) that are on the ground from deposition as fallout.</p>
</blockquote>
<p>However, it goes on to say that the mine cannot be directly faulted for this, because the average rate of airborne emissions is within the guidelines outlined in its <a href="http://www.ehp.qld.gov.au/management/env-authorities/pdf/epml00977513.pdf">environmental permit</a>. The report suggests that its modelled blood lead values do not match the actual values on children because they may be exposing themselves to extra lead by ingesting dirt, or through other sources such as lead-based paint, leaded petrol, or lead-acid batteries.</p>
<p>But this rationale fails to take into account the short-term spikes in emissions, which cause depositions that accumulate in soils and dusts, which in turn cause elevated blood lead exposures in children. The question could easily be answered by comparing the isotopic composition of lead from blood samples with that from the mine’s emissions. Disappointingly, the Glencore report did not undertake this critical analytical step to link <a href="https://www.ncbi.nlm.nih.gov/pubmed/21329917">environmental sources to actual exposures in children</a>. </p>
<h2>Another setback</h2>
<p>Authorities have been aware of lead emissions from the Mount Isa smelter since the <a href="http://trove.nla.gov.au/work/34662826?q=Queensland+Parliament+Report+of+Enquiry+into+Lead+Poisoning+and+its+Incidence%2C+Mount+Isa&c=book&versionId=42926807">early 1930s</a>. It was always a fanciful notion to suggest that emissions were not finding their way across the city and into homes, and that the contamination was somehow natural.</p>
<p>Intensive air monitoring in the community has continued for at least the past 40 years. Blood lead surveys and <a href="http://www.sciencedirect.com/science/article/pii/S0883292710000740">internal memos</a>, along with <a href="http://link.springer.com/article/10.1007%2Fs11356-015-4100-z">environmental assessments</a> from various government agencies, have provided significant prior knowledge of the nature, extent and cause of the problem. In 2010, Queensland’s chief medical officer Jeanette Young <a href="http://www.theaustralian.com.au/news/investigations/the-toll-lead-takes-on-isas-infants/news-story/1efdd23c59204894cd5061877cb44ce8">told The Australian newspaper</a>: </p>
<blockquote>
<p>I do know the cause; it is emissions being released from the mine. If you think where it is coming from, it is coming from emissions from the smelter that are going up in the air and they are depositing across the town fairly evenly. </p>
</blockquote>
<p>Thus, in this sense, the latest study merely represents confirmation of what many people already knew.</p>
<p>Yet despite this overdue acknowledgement of the problem, the report implies that Glencore is not taking full ownership of the issue. The overriding message to Mount Isa’s residents is that it falls to them to keep themselves free from dangerous contamination.</p>
<p>In this sense, this is yet another setback in improving the living conditions for the community of Mount Isa, particularly young children who are the most vulnerable to the adverse and life-long effects of lead exposure.</p><img src="https://counter.theconversation.com/content/72862/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor is affiliated with: Broken Hill Lead Reference Group. LEAD Group Inc. (Australia). NSW Government Lead Expert Working Group - Lead exposure management for suburbs around the former Boolaroo (NSW) Pasminco smelter site, Dec 2014–ongoing. Appointed by NSW Environment Minister to review NSW EPA’s management of contaminated sites, October 2015–ongoing. Macquarie’s VegeSafe project receives funding support via voluntary donations from the public and cash and in-kind support for a broader evaluation of the use and application of field portable XRFs OIympus Australia Pty Ltd and the National Measurement Institute, North Ryde, Sydney. In addition, MP Taylor has previously provided evidence-based expert report and advice for Slater and Gordon Lawyers in regard to their court action against Mount Isa Mines.</span></em></p><p class="fine-print"><em><span>Chenyin Dong is funded by the international Macquarie University Research Excellence Scholarship (iMQRES) and New South Wales Environmental Protection Authority scholarship (MQ9201600680).</span></em></p><p class="fine-print"><em><span>Paul Harvey receives funding from a Macquarie University Research Excellence Scholarship (MQRES). </span></em></p>Glencore has admitted responsibility for air pollution in Mount Isa, but its latest report puts the onus on residents to minimise their exposure to lead contamination in their homes.Mark Patrick Taylor, Professor of Environmental Science, Macquarie UniversityChenyin Dong, PhD Candidate in Environmental Science, Macquarie UniversityDr Paul Harvey, Researcher of Environmental Science, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/633642016-08-16T19:46:50Z2016-08-16T19:46:50ZMeat inspection must be beefed up in Africa to cull food-borne diseases<figure><img src="https://images.theconversation.com/files/134093/original/image-20160815-15270-tfltxf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Meat and animal products are important sources of protein. They are also a delicacy in most meals in Africa. But they can also be potentially hazardous. While most Africans relish meat, proper meat inspection has eluded the continent for decades. </p>
<p>Meat inspection is the process that monitors the slaughtering of animals. It is done by a veterinary doctor and meat inspection officers at accredited abattoirs. They work together to ensure that ill animals are separated from healthy animals.</p>
<p>Recent <a href="http://www.ncbi.nlm.nih.gov/pubmed/24833237">research</a> has shown meat inspection practices in most developing nations are inadequate and that meat is becoming a major source of <a href="http://online.liebertpub.com/doi/pdf/10.1089/mdr.2014.0222">microbes</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/26939246">parasites</a> and <a href="http://www.scielo.org.za/pdf/sajc/v65/26.pdf">heavy metals</a>.</p>
<p>Ineffective meat inspection increases the possibility of someone contracting <a href="http://www.who.int/neglected_diseases/diseases/en">food- borne neglected tropical diseases</a> like <a href="http://emedicine.medscape.com/article/230112-overview">trematode infection</a>, <a href="http://www.cdc.gov/parasites/taeniasis/">taeniasis</a>, <a href="http://emedicine.medscape.com/article/215589-overview">cysticercosis</a>, and <a href="http://www.mayoclinic.org/diseases-conditions/toxoplasmosis/basics/causes/con-20025859">toxoplasmosis</a>. The <a href="http://www.who.int/neglected_diseases/diseases/en/">effects</a> of these diseases ranges from mild symptoms such as diarrhoea to severe conditions such as epilepsy (which can develop from cysticercosis and taeniasis) as well as stillbirths and miscarriages, which can result from toxoplasmosis.</p>
<p>Ineffective meat inspection has also been shown to contribute towards the <a href="http://www.annualreviews.org/doi/full/10.1146/annurev-food-041715-033251">emergence of “superbugs”</a> that are resistant to most antibiotics and the accumulation of “heavy metals” which are harmful to our health.</p>
<p>This means it’s hugely important to upgrade existing meat inspection practices and improve public education. </p>
<h2>Why meat needs inspection</h2>
<p>Internationally, meat inspection procedures are guided jointly by the Food and Agriculture Organisation and the World Health Organisation through <a href="http://www.fao.org/fao-who-codexalimentarius/en/">international food standards</a>. Its <a href="http://www.fao.org/docrep/003/t0756e/T0756E01.htm#ch1">meat inspection programme</a> has two main objectives:</p>
<ul>
<li><p>to make sure that, before animals are slaughtered, abnormal ones are dealt with separately from healthy, physiologically normal ones; and, </p></li>
<li><p>to ensure that meat from animals is free from disease, is wholesome and carries no risk to human health.</p></li>
</ul>
<p>But many developing countries do not adhere to the Food and Agriculture Organisation’s meat inspection guidelines and do not have enough meat inspection officers. </p>
<p>This has led to a rise in various food borne diseases. An international workshop on the issue <a href="http://www.sciencedirect.com/science/journal/0001706X/87/1">found</a> that many developing countries were failing to fully implement their own meat inspection laws and regulations and that they lacked well-established and structured slaughtering facilities. </p>
<p>This is supported by evidence gathered in Nigeria and research done in Ethiopia.</p>
<p>In Oyo state in a Nigeria, which has a population of 5.5 million <a href="http://www.population.gov.ng/index.php/state-population">people</a>, I found that there were fewer than 30 veterinary officers in charge of meat inspection and that the <a href="https://www.thecable.ng/abattoirs-need-urgent-attention">abattoirs were in a despicable state</a>. </p>
<p>Similarly, a <a href="http://www.ncbi.nlm.nih.gov/pubmed/24833237">study</a> done in eastern Ethiopia found that more than 60% of the people interviewed had been infected with cysticercosis once in the year before the study. Of these, 99% had eaten raw or under-cooked beef. Of the 898 local zebu cattle slaughtered for human consumption nearly 20% harboured at least one cyst in the animals’ shoulder muscles, liver and hearts. All these cuts are preferred by local people to prepare and eat as raw or inadequately cooked meat dishes. </p>
<h2>Heavy metals in meat</h2>
<p>Adequate meat inspection also ensures that there is not an oversupply of “heavy metals” in food. </p>
<p>The right amount of metals such as iron, copper, zinc and manganese in foods are important. Essential minerals play a role in our bodies functioning efficiently.</p>
<p>But there are several “heavy metals” which could be hazardous if they are found in the body, even at low levels. These include <a href="http://ec.europa.eu/food/fs/sfp/fcr/fcr02_en.pdf">lead, cadmium and mercury</a>. They can have varying <a href="http://bmb.oxfordjournals.org/content/68/1/167.full">health effects</a> and have been found to cause cancers, kidney damage and damage to the nervous system.</p>
<p>Several studies have shown how heavy metals find their way into the food chain in <a href="http://www.scielo.org.za/pdf/sajc/v65/26.pdf">various parts of Africa</a>. These were <a href="http://www.sciencedirect.com/science/article/pii/S0278691500001769">found</a> in higher doses than <a href="ftp://ftp.fao.org/codex/meetings/CCCF/cccf5/cf05_INF.pdf">recommended</a>. </p>
<p>One study found a high concentration of heavy metals in <a href="https://www.researchgate.net/publication/265851267_Heavy_Metals_Analysis_of_Local_and_Exotic_Poultry_Meat">poultry</a> and <a href="http://www.academicjournals.org/article/article1379596726_Nwude%20et%20al.pdf">beef</a> in <a href="http://maxwellsci.com/jp/abstract.php?jid=RJASET&no=80&abs=07">regions</a> of Nigeria. </p>
<h2>Superbugs and meat inspection</h2>
<p>Superbugs are an emerging group of bacteria that are resistant to several types of antibiotics. In selected cases they have severely crippled established health systems. In one case in the UK, an <a href="http://www.telegraph.co.uk/news/2016/07/08/intensive-care-unit-closed-as-three-people-die-from-new-superbug/">intensive care unit had to be closed down</a> after people died from a superbug.</p>
<p>In South Africa, microbiologists <a href="http://www.ncbi.nlm.nih.gov/pubmed/27138657">reported</a> that the emergence of superbugs meant only a limited range of antibiotics were available to treat infected patients. </p>
<p>Research shows that while some superbugs evolve as a result of antibiotic misuse, others are the result of <a href="http://jama.jamanetwork.com/article.aspx?articleid=209435">superbugs</a> being transferred from eating and handling meat contaminated with resistant bacteria. One study <a href="http://online.liebertpub.com/doi/pdf/10.1089/mdr.2014.0222">identified</a> multidrug resistant bugs in food animals. These provide the transmission link of the superbug from animals to humans.</p>
<p>A realistic solution to this would be to demand that veterinarians are more involved in overseeing the use of antibiotics on farms. </p>
<p>Alternatively, it would be a good move to set up a system that could track and report resistance during food inspection within each country. Both the <a href="https://www.cdc.gov/narms/">US</a> and <a href="http://www.danmap.org/">Denmark</a> have done this. In both instances government departments and public health officials work together to track resistance to antibiotics and ensure that safe foods are delivered to the public. </p>
<h2>The way forward</h2>
<p>Most African nations have various food and drug regulatory agencies. But the local meat industry has been neglected. This needs to change. </p>
<p>In the absence of improved meat inspection practises there are initiatives that citizens can implement themselves. The preparation of their food and meat is one. A study in <a href="http://www.sciencedirect.com/science/article/pii/S0168160505000826">Senegal</a> highlighted how certain cooking methods reduce the risk of transmission of food borne pathogens. </p>
<p>Most traditional West African meat dishes involve a combination of boiling, frying and cooking in sauces at boiling temperature for at least 30 minutes. These stages can help remove superbugs and parasites that cause most neglected tropical diseases. </p>
<p>Ultimately in the long run, however, the onus lies with governments.
Their responsibility is to implement meat inspection legislation and to adequately monitor livestock activities from the farm to the fork with oversight by veterinarians. In addition, they need to create laboratories that are responsible for regular testing and monitoring meat. This will that ensure safe food is delivered and reliable approaches to prevent diseases are in place.</p><img src="https://counter.theconversation.com/content/63364/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oyebola Oyesola 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>Food-borne diseases will continue to thrive unless Africa’s meat inspection programmes are upgraded.Oyebola Oyesola, Graduate Student in Immunology and Infectious DIsease, Cornell UniversityLicensed as Creative Commons – attribution, no derivatives.