tag:theconversation.com,2011:/africa/topics/silver-4038/articlesSilver – The Conversation2024-02-15T13:32:45Ztag:theconversation.com,2011:article/2164242024-02-15T13:32:45Z2024-02-15T13:32:45ZGold, silver and lithium mining on federal land doesn’t bring in any royalties to the US Treasury – because of an 1872 law<figure><img src="https://images.theconversation.com/files/575104/original/file-20240212-17-qfzo4g.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5483%2C3655&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Aerial view of the Pinto Valley copper mine, located on private and U.S. national forest lands in Gila County, Ariz.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/aerial-view-of-pinto-valley-copper-mine-in-gila-county-news-photo/1410152071">Wild Horizon/Universal Images Group via Getty Images</a></span></figcaption></figure><p>When Congress opened U.S. public lands for mining in 1872, the nation was less than a century old. Miners used picks, shovels and pressurized water hoses to pry loose valuable minerals like gold and silver. </p>
<p>Today, mining is a high-technology industry, but it is still governed by the <a href="https://www.govinfo.gov/content/pkg/COMPS-5337/pdf/COMPS-5337.pdf">Mining Law of 1872</a>. As was true 150 years ago, companies can mine valuable mineral deposits from federal lands without paying any royalties to the U.S. Treasury. </p>
<p>Even when lands that formerly were available for mining receive new protected status as national parks or monuments, the 1872 mining law <a href="https://www.nps.gov/subjects/energyminerals/development-in-parks.htm">protects existing mining claims on those lands</a>. That’s why a company called Energy Fuels Inc. <a href="https://www.azcentral.com/story/news/local/arizona-environment/2024/01/10/a-uranium-mine-near-the-grand-canyon-is-operating-despite-opposition/72163283007/">just started mining uranium in January 2024</a> at a site in Arizona 10 miles from the Grand Canyon and inside a <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2023/08/08/fact-sheet-president-biden-designates-baaj-nwaavjo-itah-kukveni-ancestral-footprints-of-the-grand-canyon-national-monument/">new national monument</a>.</p>
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<a href="https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Men wield shovels and wheelbarrows next to a small timbered opening in a hillside." src="https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=617&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=617&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=617&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=775&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=775&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575103/original/file-20240212-16-7p58kw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=775&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">Gold prospectors mining at Lake Coeur d'Alene, Idaho, circa 1885.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/gold-prospectors-shovel-sand-and-gravel-into-a-rocker-box-a-news-photo/1478786322">Graphic House/Archive Photos via Getty Images</a></span>
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<p>Minerals like lithium, uranium and copper are essential for <a href="https://theconversation.com/the-us-is-worried-about-its-critical-minerals-supply-chains-essential-for-electric-vehicles-wind-power-and-the-nations-defense-157465">shifting from fossil fuels to renewable energy</a>, and for many other uses in our increasingly technological society. The Biden administration wants to produce these materials domestically, rather than relying on foreign sources – especially from countries like the Democratic Republic of Congo, where <a href="https://www.dol.gov/agencies/ilab/combatting-child-labor-democratic-republic-congos-cobalt-industry-cotecco">child labor abuses in the mining industry persist</a>. </p>
<p>As a <a href="https://www.researchgate.net/scientific-contributions/Sam-Kalen-2146924596">natural resource and public land scholar</a>, I agree with many others who argue that the 1872 mining law is <a href="https://earthworks.org/releases/biden-administration-working-group-recommendations-offer-first-step-to-protect-communities-environment-from-destructive-mining/">archaic and overdue for an update</a>. It allows the modern mining industry to develop valuable resources on public lands without returning any value to the American taxpayer, and to mine in areas that have sensitive ecosystems or contain important cultural resources for Indigenous peoples.</p>
<h2>Royalty-free development</h2>
<p>Allowing citizens to enter, explore and ultimately develop claims on federal lands with valuable mineral deposits was part of a broad push to settle the West. Congress enacted the 1872 mining law just a decade after the <a href="https://www.archives.gov/education/lessons/homestead-act">Homestead Act</a>, which gave settlers up to 160 acres of public land for a small claim fee if they lived on it and farmed it, and three years after the <a href="https://guides.loc.gov/this-month-in-business-history/may/completion-transcontinental-railroad">completion of the transcontinental railroad</a> in 1869.</p>
<p>Today, open federal public lands are managed by either the <a href="https://www.fs.usda.gov/">U.S. Forest Service</a> or the <a href="https://www.blm.gov/">Bureau of Land Management</a>. In either case, they are considered available for hard rock mining. </p>
<p>Companies that want to develop <a href="https://www.blm.gov/programs/energy-and-minerals/coal">coal</a>, <a href="https://www.blm.gov/programs/energy-and-minerals/oil-and-gas/about">oil, natural gas</a>, <a href="https://www.blm.gov/programs/energy-and-minerals/renewable-energy/strategy">geothermal energy and solar or wind power</a> on public lands sign leases and pay royalties in return for using these lands to generate private wealth. For example, the current royalty rate for oil and gas production on federal land is <a href="https://www.doi.gov/pressreleases/interior-department-takes-steps-modernize-oil-and-gas-leasing-public-lands-ensure-fair">16.67% of the market value</a> of these fuels.</p>
<p>Not so for mining companies, even if they extract precious metals like gold and silver. According to an Interior Department estimate, the value of gold, silver, copper, molybdenum, lead and zinc mined on federal lands in the West in 2019 was <a href="https://www.doi.gov/media/document/mriwg-report-final-508-pdf">approximately US$4.9 billion</a>. If the companies had paid royalties, they would have returned millions of dollars to the U.S. Treasury.</p>
<p>A miner who locates a valuable mineral deposit on public lands and complies with federal and state law enjoys a right to explore and then develop the land, and can even prevent others from doing so. There are two principal qualifying rules.</p>
<p>First, claims can only be located on open public lands that have not been withdrawn from use for other purposes, such as protecting cultural resources or wilderness areas. Second, the 1872 law only applies to valuable mineral deposits, which it defines as those on lands containing locatable minerals that a prudent person would develop because the minerals can be mined and marketed at a profit. </p>
<p>These materials may include precious minerals, such as gold and silver; metallic minerals, such as uranium, lead, copper or zinc; or nonmetallic minerals, such as some types of limestone, bentonite and asbestos. High-profile mining proposals today include <a href="https://news.bloomberglaw.com/environment-and-energy/epa-proposes-lead-copper-limits-near-planned-arizona-mine">copper mines in Arizona</a> and <a href="https://apnews.com/article/lithium-mine-tribes-climate-energy-lawsuit-nevada-7a65eee7d78d93a1e44e3f8e10445143">lithium mines in Nevada</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/uGcxc6jV8Go?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Native Americans have fought construction of a lithium mine at Thacker Pass in northern Nevada, which they contend sits on their ancestral land. Environmentalists are divided over the project, which would supply material for advanced batteries.</span></figcaption>
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<h2>Decades of debate</h2>
<p>Calls for reforming the 1872 law first surfaced in the late 19th century and have persisted ever since. </p>
<p>After all, the law transferred valuable public resources to private hands at virtually no cost, while saddling the public with the resulting environmental burdens, such as ponds <a href="https://www.gao.gov/assets/rced-91-145.pdf">contaminated with toxic cyanide</a>. Mining on public lands, especially prior to the 1970s, left <a href="https://www.gao.gov/products/gao-23-105408">a multitude of contaminated zones</a> that federal agencies are still working to clean up at taxpayer expense. </p>
<p>Today, mining operations are subject to modern land management and environmental laws, such as the Clean Water Act. But these laws were not written specifically to address mining and do not fully cover issues such as <a href="https://earthworks.org/files/publications/FACTSHEET_Mining-industry-exploits-clean-water-act-loopholes.pdf">disposal of mine waste</a>. </p>
<p>University of California legal scholar <a href="https://expertfile.com/experts/john.leshy/john-leshy">John Leshy</a>, a former solicitor at the Interior Department and the nation’s premier mining law expert, forcefully described in his 1987 book, “<a href="https://www.routledge.com/The-Mining-Law-A-Study-in-Perpetual-Motion/Leshy/p/book/9781138951877">The Mining Law: A Study in Perpetual Motion</a>,” how this statute languished for decades, widely understood as ill-suited to modern times yet eluding reform. Former University of Colorado law professor <a href="https://www.colorado.edu/law/2023/06/12/memoriam-charles-wilkinson-trailblazer-justice-earth-and-american-indian-law">Charles Wilkinson</a> called the law a “lord of yesterday” in his classic 1992 book, “<a href="https://islandpress.org/books/crossing-next-meridian">Crossing the Next Meridian: Land, Water, and the Future of the West</a>.” </p>
<p>Reform advocates support adopting the type of <a href="https://www.eenews.net/articles/citing-clean-energy-progressives-mount-mining-law-overhaul/">traditional leasing model</a> that is used for most other resources on public lands in the U.S. and elsewhere. As an example, for oil and gas production <a href="https://www.blm.gov/programs/energy-and-minerals/oil-and-gas/leasing/general-leasing">on federal lands</a> and <a href="https://www.boem.gov/oil-gas-energy/leasing">offshore in federal waters</a>, agencies identify areas with development potential and hold competitive auctions to lease parcels for exploration and development.</p>
<p>Reformists also favor tighter environmental safeguards that would address issues such as <a href="https://www.nwf.org/Our-Work/Waters/Hardrock-Mining">management and disposal of mining wastes</a>. Finally, they argue that mining should be prohibited in areas that are ecologically sensitive or are <a href="https://www.csis.org/analysis/pathway-responsible-mining-indian-country">important to Indigenous peoples or tribal nations</a>.</p>
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<a href="https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bright orange water flows from a pipe into a plastic-lined settling pond." src="https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575114/original/file-20240212-18-ql6lrc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Water from a 2015 spill at the abandoned Gold King mine in southwest Colorado flows into a holding pond. The spill released 3 million gallons of water laced with toxic metals, contaminating rivers in three states and the Navajo Nation.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/NewMexicoMineSpillSettlementGrants/f4d3c34b13894facae77fc6ef413c45a/photo">AP Photo/Brennan Linsley</a></span>
</figcaption>
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<p>In contrast, the mining industry and its supporters complain that <a href="https://www.nma.org/pdf/041508_mining_law.pdf">existing laws hinder mining activities</a>. In their view, the federal government applies the 1872 mining law in a way that forces companies to spend years securing necessary approvals. A 2015 report prepared for the mining industry estimated that the average time required to secure all permits for a large mine in the U.S. was <a href="https://nma.org/wp-content/uploads/2016/09/SNL_Permitting_Delay_Report-Online.pdf">seven to 10 years</a>, compared with two years in Canada and Australia.</p>
<p>The industry also contends that imposing a royalty requirement would make it hard for companies to <a href="https://www.nytimes.com/2023/09/12/climate/mining-federal-lands-metals.html">produce critical materials profitably</a>, although these companies currently <a href="https://www.gao.gov/products/b-330854">pay royalties to 12 western states</a> for mining on state land.</p>
<p>In September 2023, the Interior Department <a href="https://www.doi.gov/pressreleases/biden-harris-administration-report-outlines-reforms-needed-promote-responsible-mining">released a 168-page report</a> making recommendations for improving mining on public lands. It calls for:</p>
<p>– Putting greater emphasis on environmental protection in mine permitting;</p>
<p>– Preventing mining in areas that are important to tribal nations and Indigenous peoples;</p>
<p>– Replacing the 1872 mining law with a more traditional leasing system that would charge royalties of 4% to 8%; and</p>
<p>– Charging mining companies a fee that would be used to help clean up abandoned mine sites, similar to a fee that <a href="https://revenuedata.doi.gov/how-revenue-works/aml-reclamation-program/">coal mining companies have paid since 1977</a>.</p>
<p>Bills are <a href="https://www.congress.gov/bill/118th-congress/senate-bill/1281">pending now</a> in Congress, introduced by <a href="https://www.congress.gov/bill/118th-congress/house-bill/2925">legislators from Nevada</a>, a major mineral-producing state. These measures would retain the structure of the 1872 law while taking steps to streamline permitting for large-scale mining activities.</p>
<h2>Balancing critical minerals and conservation</h2>
<p>Mining conversations are taking on new urgency as the U.S. pursues a clean energy transition and works to secure essential materials for a modern technology-based economy. In my view, focusing myopically on critical minerals and moving forward with a new era of domestic mining should not occur without reforming the 1872 law. </p>
<p>A rewrite of the law could streamline permitting and create a planning process for mining on public land that mirrors the existing process for energy projects. Halting climate change and powering a new green economy may involve some trade-offs between short-term and long-term environmental protection goals. </p>
<p>But these choices can be made thoughtfully, with a focus on protecting America’s treasured public lands. In 1872, our nation’s lands and natural resources may have seemed inexhaustible; today, we know they are finite, and that using them responsibly means balancing development and stewardship.</p><img src="https://counter.theconversation.com/content/216424/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sam Kalen served as Special Assistant to the Associate Solicitor for Minerals and Resources at the US Department of the Interior from 1994-1996. Views expressed in this article are solely those of the author.</span></em></p>Hard rock minerals like gold, silver, copper and lithium on public lands belong to the American public, but under a 150-year-old law, the US gives them away for free.Sam Kalen, Associate Dean and Professor of Law, University of WyomingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2215112024-01-29T14:53:48Z2024-01-29T14:53:48ZFrom mud and vinegar to 3D printing skin, the way we treat wounds still challenges humanity<p>Whether it’s the sting of a paper cut or the trauma of battle injury, wounds are woven into the tapestry of human experience. And since ancient times, we’ve fought the enemy that lurks within them – infection. </p>
<p>The constant threat of injury on the battlefield led to the search for new ways to combat wound infection. But early surgical procedures lacked the sterile instruments available today, meaning that for many years, surgery came with the added risk of post-operative <a href="https://cha.com/wp-content/uploads/2017/11/AJIC-2012-Infection-Control-Through-the-Ages.pdf">wound infection</a>, resulting in high numbers of deaths. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3601883/">Ancient practices</a>, such as using oils, mud, turpentine, or honey to treat wounds, were common around 2000BC. The Greek physician Hippocrates (460-377BC) <a href="https://www.dermatologytimes.com/view/acetic-acid-and-wound-healing">used vinegar</a> to clean wounds, followed by bandaging to keep dirt at bay.</p>
<p>While the first hospitals were <a href="https://scientificsurgery.bjs.co.uk/article/the-surgery-of-theodoric-ca-a-d-1267-translated-from-the-latin-by-eldridge-campbell-m-d-and-james-colton-m-a-volume-i-books-i-and-ii-8-38-x-5-12-in-pp-223-xi-with-coloured-front/">established</a> in Europe in the middle ages, they were dangerous and brutal places. Wound infection rates were high because of unsanitary conditions and the use of cautery, which involved pushing a burning iron into a patient’s wound until it reached the bone.</p>
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<img alt="A drawing of a pot containing a fire with several medical instruments poking out of it." src="https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&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">A receptacle for burning coal to heat cautery instruments.</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/gcg933n2/images?id=jghkdnp4">Wellcome Collection</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>By the 1860s, the pioneering surgeon Joseph Lister had revolutionised wound infection treatment by introducing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895849/">carbolic-acid-soaked bandages</a>. And Robert Wood Johnson, who founded Johnson & Johnson, <a href="https://wounds-uk.com/journal-articles/sterilised-gauze-and-baby-powder-robert-wood-johnson-i-and-frederick-barnett-kilmer/">produced</a> the first sterile gauze bandages by 1890. The combination of antiseptic and sterile bandage marked a turning point in the evolution of wound treatment and infection control.</p>
<p>The discovery of penicillin by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4520913/">Alexander Fleming</a> in 1928 was also a pivotal moment in the treatment of wound infections. By the 1940s, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5369031/">penicillin</a> was being used to treat second world war soldiers who had wound infections that would have been deemed fatal in previous years. For less serious wounds, Lister’s approach of using a dressing and an antiseptic was still used.</p>
<p>Substances like <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756674/">silver</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/12914356/">iodine</a> have also been recognised for their antimicrobial properties since the 1800s. Iodine, though effective, caused pain and skin discolouration until safer and less painful formulations were developed in 1949. <a href="https://bnf.nice.org.uk/wound-management/antimicrobial-dressings/">These formulations</a> endure in modern wound dressings.</p>
<p>For everyday cuts and scrapes, a simple cleaning with water and application of antiseptic cream is usually enough. This helps to prevent the inadvertent introduction of bacteria into the wound, minimising the risk of additional pain and swelling. </p>
<p>But while most wounds nowadays heal without issue, some become become infected. Research published in 2021 showed that <a href="https://wounds-uk.com/wp-content/uploads/sites/2/2023/02/68803cd147c4d81a02b9cc56823f19a1.pdf">3.8 million</a> people were having their wounds managed by the NHS between 2017 and 2018, up 71% from between 2012 and 2013. They included surgical wounds, leg ulcers and burns. This shows how hard it can be to care for wounds that are difficult to heal and particularly susceptible to infections.</p>
<h2>Modern-day challenges</h2>
<p>One of the biggest challenges in the modern-day treatment of wound infection is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">antibiotic resistance</a>. This happens when bacteria develop the ability to defeat the drugs designed to kill them. Resistant infections can be difficult, and sometimes impossible, to treat. </p>
<p>Many bacteria have also become resistant to the antimicrobial ingredients used in wound dressings. This is the case for <a href="https://www.sciencedirect.com/science/article/pii/S0195670104005201">silver-based</a> wound dressings, which are often used to treat chronic wound infections. This type of wound characteristically <a href="https://www.nature.com/articles/s41572-022-00377-3">fails to heal</a>, and can remain an open, infected wound for many months – or even years. As well as the devastating effect on people’s quality of life, this also places a huge financial burden on the NHS.</p>
<p>The constant fight against wound infections drives extensive research for new, safe and effective treatments. While progress is being made, a crucial hurdle lies in the <a href="https://academic.oup.com/jacamr/article/3/1/dlab027/6186407">limitations</a> of laboratory testing methods. These tests, while necessary for regulatory approval, often fail to capture the nuanced realities of wounds in the human body. </p>
<p>No two people are the same and no two wounds are the same either. This can lead to situations where treatments shine in the lab but ultimately prove ineffective in real patients.</p>
<h2>Creating wound models</h2>
<p>In response to this, scientists are tackling the limitations of lab tests by creating more realistic synthetic wound models. Some are even <a href="https://pubmed.ncbi.nlm.nih.gov/30172300/">3D printing</a> human skin (using leftovers from surgical procedures), or animal skin, complete with artificial body fluids, such as pus. The aim is to create a model environment that mimics real wounds more accurately. </p>
<p>Recently, my own <a href="https://pubmed.ncbi.nlm.nih.gov/36678466/">research group</a> has made strides in developing lab models that act like real chronic wounds when treated with antimicrobial dressings. While not perfect, our models are a step in the right direction, contributing to the development of formulations with promising potential for treating wound infections in the future.</p>
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Read more:
<a href="https://theconversation.com/we-built-a-human-skin-printer-from-lego-and-we-want-every-lab-to-use-our-blueprint-203170">We built a human-skin printer from Lego and we want every lab to use our blueprint</a>
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</p>
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<p>As we navigate the complexities of wound care, the quest for new, effective and safe treatments continues, driven by the efforts of scientists worldwide. We are working towards a future where the management of difficult-to-heal wounds and infections improves, enhancing both individual wellbeing and the efficiency of health systems.</p><img src="https://counter.theconversation.com/content/221511/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Maddocks 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>Keeping wounds clean and infection free has challenged people for thousands of years.Sarah Maddocks, Lecturer in Microbiology, Cardiff Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1563582021-03-16T17:15:38Z2021-03-16T17:15:38ZRare metals play a strategic and essential role in health<figure><img src="https://images.theconversation.com/files/390473/original/file-20210318-13-1qdpsbi.jpg?ixlib=rb-1.1.0&rect=27%2C43%2C2591%2C1653&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">While people may be familiar with precious metals, which are often at the heart of conflicts, there are also metals that are essential to good health. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The COVID-19 pandemic has highlighted the fact that most countries do not have sufficient health sovereignty to face such a crisis. Shortages of masks, respirators, medicines and now vaccines were felt in many countries, even the most advanced. These problems show that our societies are dependent on certain countries for essential products.</p>
<p>But what about metals?</p>
<p>Our <a href="http://www.industrie-minerale-territoires.fr/index.en.htm">research team</a> has been working for a few years on the interactions between earth sciences and social sciences, especially around the concept of social geology and the dynamics of resource-rich territories.</p>
<h2>Strategic metals</h2>
<p>The notion of critical and strategic minerals goes back to the wars of the 19th century. At the end of the Second World War, the United States built up stocks of metals. However, the overabundance of metals at the end of the 20th century and globalization led western states to abandon their proactive policy in this field. Awareness of dependence on imported mineral resources did not return until the late 1990s, with the emergence of Asian economies and new monopolies.</p>
<p>The list of critical and strategic metals varies from country to country, ranging from a dozen for the French National Defence to the <a href="https://www.usgs.gov/news/interior-releases-2018-s-final-list-35-minerals-deemed-critical-us-national-security-and">35 metals</a> listed in the decree of President Donald Trump in 2018.</p>
<p>Why do we have these lists of metals? They reflect the major issues of the past, those of the wars of the 20th century and the conflicts feared for the future. More generally, they mark the technological and social crises that have hit our societies during the past 50 years and which have led to what the German sociologist <a href="https://www.sciencedirect.com/topics/social-sciences/risk-society">Ulrich Beck has called the risk society</a>.</p>
<p>Each crisis has left in its wake new technological solutions, secure supply chains and an increased awareness of the dependence on various metals. Here are a few examples.</p>
<h2>From oil to gold</h2>
<p>In 1973, the oil crisis highlighted the energy fragility of most developed countries. Some countries turned to nuclear power, others to hydroelectricity. Uranium mines were put into production everywhere, from Saskatchewan to Niger. The price of ore soared in 1978 and production peaked in 1980.</p>
<p>The terrorist crisis of 2001 in turn accelerated the development of information technology in the defence industries and the consumption of high-tech metals increased accordingly. The price of tantalum reached its highest point in 2000 and world production peaked in 2004. This demand encouraged artisanal production in eastern Congo, which has been a centre of conflict for 20 years.</p>
<p>The nuclear crises following the 1986 Chernobyl and 2011 Fukushima accidents encouraged a shift to metal-intensive renewable energies, particularly wind power. The price of rare-earth elements exploded to a peak in 2010 and production doubled in the following decade.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photograph of ore" src="https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/389581/original/file-20210315-17-1y54naj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An image of the rare ore and radite at the Kwyjibo Project in North Shore, Qué.</span>
<span class="attribution"><span class="source">(Authors)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Finally, in 2008, the financial crisis weakened global markets and led to a resumption of gold purchases, particularly by the Russian and Chinese central banks, which helped support the price of the precious metal.</p>
<p>It is therefore understandable that each crisis is accompanied by new needs in minerals and the need to secure these new metal sectors.</p>
<h2>Metals and health issues</h2>
<p>Metals have been used for human health for thousands of years. <a href="https://www.webmd.com/balance/guide/ayurvedic-treatments">Ayurveda</a>, a traditional medicine that has been practised for 3,000 years in India, employs lead, mercury and arsenic to treat various ailments. Toxic in excessive quantities, these metals can, however, become indispensable in certain medicines and medical and orthopedic equipment.</p>
<p>Today, pharmacology uses more than a dozen metals or metalloids for various conditions: iron for anemia, bismuth, cobalt and nickel for gastric problems, lithium for depression, antimony for leishmaniasis, platinum or radioactive metals for cancer, arsenic for psoriasis. Gold can even help with the treatment of rheumatoid arthritis.</p>
<p>Metals are also widely used in prostheses: a mouth treated by a dental technician could contain up to 32 different metals! Medical imaging also uses many metals, from X-rays to nuclear medicine. Nuclear magnetic resonance (NMR) is based on rare-earth magnets, while 20 per cent of the world’s gadolinium is used for solutions that increase the contrast of NMR images.</p>
<h2>Metals and the COVID-19 crisis</h2>
<p>And COVID-19? Metals are found in both the prevention and treatment of this new disease.</p>
<p>Copper has been a favourite <a href="https://www.smithsonianmag.com/science-nature/copper-virus-kill-180974655/">for creating anti-microbial surfaces</a>, which can reduce hospital outbreaks and kill viruses and bacteria in less than two hours. Zinc can boost the immune system and has already been used against viruses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="two men leaving a helicopter" src="https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/389921/original/file-20210316-19-1f95ygm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rare metals exploration, North Rae Project in Ungava, Qué.</span>
<span class="attribution"><span class="source">(Authors)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Thus, in addition to strategic metals at the heart of conflicts, there are metals that are essential to health. The COVID-19 pandemic caused shortages of hygiene and pharmaceutical products. Advanced medical equipment, full of electronic components and therefore high-value metals, was sometimes lacking.</p>
<p>Most western countries depend on imported metals. It is therefore time to seriously discern what is really indispensable, what essential metals are in the health sector and how to guarantee their supply for use in the next health crises.</p><img src="https://counter.theconversation.com/content/156358/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michel Jébrak receives research funding from public (the Natural Sciences and Engineering Research Council (NSERC) and Fonds de Recherche du Québec – Nature et technologies, also known as FRQNT) and private (mining companies) organizations. He is a member of the Ordre des Géologues du Québec. </span></em></p><p class="fine-print"><em><span>Yann Gunzburger receives funding from public organizations and, in the form of sponsorships, from private companies, particularly in the context of a research and training chair on the relationship between mining projects and territories. He is a member of the Société de l'Industrie Minérale.</span></em></p><p class="fine-print"><em><span>Jack-Pierre Piguet ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Iron fights anemia. Bismuth relieves gastric problems. Lithium acts against depression and gold can treat rheumatoid arthritis. Metals are precious tools for good health.Michel Jébrak, professeur émérite en ressources minérales, Université du Québec à Montréal (UQAM)Jack-Pierre Piguet, Professeur, Laboratoire GeoRessources, Université de LorraineYann Gunzburger, Professeur des universités, laboratoire GeoRessources, Université de LorraineLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1479722021-01-11T13:14:46Z2021-01-11T13:14:46ZConsumer electronics have changed a lot in 20 years – systems for managing e-waste aren’t keeping up<figure><img src="https://images.theconversation.com/files/376831/original/file-20201231-49872-1uzkolc.jpg?ixlib=rb-1.1.0&rect=17%2C11%2C3864%2C2572&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most of the world's electronics are not recycled, posing health and environmental risks. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/abandoned-and-rusted-laptop-lying-on-riverbed-royalty-free-image/108162816">catscandotcom/Getty Images</a></span></figcaption></figure><p>It’s hard to imagine navigating modern life without a <a href="https://blogs.worldbank.org/opendata/are-cell-phones-becoming-more-popular-toilets">mobile phone</a> in hand. Computers, tablets and smartphones have transformed how we communicate, work, learn, share news and entertain ourselves. They became even more essential when the COVID-19 pandemic moved classes, meetings and social connections online. </p>
<p>But few people realize that our reliance on electronics comes with steep environmental costs, from mining minerals to disposing of used devices. Consumers can’t resist faster products with more storage and better cameras, but constant upgrades have created a <a href="https://time.com/5594380/world-electronic-waste-problem/">growing global waste challenge</a>. In 2019 alone, people discarded <a href="https://www.itu.int/en/ITU-D/Environment/Documents/Toolbox/GEM_2020_def.pdf">53 million metric tons of electronic waste</a>.</p>
<p>In our work as <a href="https://scholar.google.com/citations?user=oZyg9b4AAAAJ&hl=en">sustainability researchers</a>, we study how consumer behavior and technological innovations influence the products that people buy, how long they keep them and <a href="https://scholar.google.com/citations?user=z6q5FZMAAAAJ&hl=en">how these items are reused or recycled</a>. </p>
<p>Our research shows that while e-waste is rising globally, it’s <a href="https://doi.org/10.1111/jiec.13074">declining in the U.S.</a> But some innovations that are slimming down the e-waste stream are also making products harder to repair and recycle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376843/original/file-20201231-15-1o0ofkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sending electronics to junkyards or landfills wastes an opportunity to recycle valuable materials inside them.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/junkyard-with-old-computer-and-electronic-parts-ca-news-photo/144074229">Joe Sohm/Visions of America /Getty Images</a></span>
</figcaption>
</figure>
<h2>Recycling used electronics</h2>
<p>Thirty years of data show why the volume of e-waste in the U.S. is decreasing. New products are <a href="https://apnews.com/article/bb5ff45b98f64123b3d408dd4a336b59">lighter and more compact than past offerings</a>. Smartphones and laptops have edged out desktop computers. Televisions with thin, flat screens have displaced bulkier <a href="https://en.wikipedia.org/wiki/Cathode-ray_tube">cathode-ray tubes</a>, and streaming services are doing the job that once required standalone MP3, DVD and Blu-ray players. U.S. households now produce about <a href="https://doi.org/10.1111/jiec.13074">10% less electronic waste by weight</a> than they did at their peak in 2015.</p>
<p>The bad news is that <a href="https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling">only about 35% of U.S. e-waste is recycled</a>. Consumers often don’t know where to recycle discarded products. If electronic devices decompose in landfills, hazardous compounds can leach into groundwater, including <a href="https://doi.org/10.1080/10962247.2019.1640807">lead</a> used in older circuit boards, mercury found in early LCD screens and <a href="https://www.aljazeera.com/news/2020/9/30/toxins-in-plastics-blamed-for-health-environment-hazards">flame retardants</a> in plastics. This process poses health risks to people and wildlife. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"809910797182914560"}"></div></p>
<p>There’s a clear need to recycle e-waste, both to protect public health and to recover valuable metals. Electronics contain rare minerals and precious metals mined in socially and ecologically <a href="https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/">vulnerable parts of the world</a>. Reuse and recycling can reduce demand for “<a href="https://www.newsecuritybeat.org/2020/09/companies-struggle-comply-conflict-mineral-reporting-rules/">conflict minerals</a>” and <a href="https://www.weforum.org/agenda/2019/01/how-a-circular-approach-can-turn-e-waste-into-a-golden-opportunity/">create new jobs and revenue streams</a>. </p>
<p>But it’s not a simple process. Disassembling electronics for repair or material recovery is expensive and labor-intensive. </p>
<p>Some recycling companies have illegally <a href="https://resource-recycling.com/e-scrap/2020/12/03/former-president-of-crt-processor-sentenced-to-prison/">stockpiled</a> or <a href="https://resource-recycling.com/e-scrap/2013/08/23/abandoned-warehouses-full-crts-found-several-states/">abandoned</a> e-waste. One Denver warehouse was called “<a href="https://resource-recycling.com/e-scrap/2013/08/23/abandoned-warehouses-full-crts-found-several-states/">an environmental disaster</a>” when 8,000 tons of lead-filled tubes from old TVs were discovered there in 2013. </p>
<p>The U.S. <a href="https://www.pbs.org/newshour/science/america-e-waste-gps-tracker-tells-all-earthfix">exports up to 40% of its e-waste</a>. Some goes to regions such as Southeast Asia that have <a href="https://www.nytimes.com/2019/12/08/world/asia/e-waste-thailand-southeast-asia.html">little environmental oversight and few measures to protect workers</a> who repair or recycle electronics. </p>
<h2>Disassembling products and assembling data</h2>
<p>Health and environmental risks have prompted 25 U.S. states and the District of Columbia to <a href="https://www.ecycleclearinghouse.org/maps.aspx">enact e-waste recycling laws</a>. Some of these measures ban landfilling electronics, while others require manufacturers to support recycling efforts. All of them target large products, like old cathode-ray tube TVs, which contain up to 4 pounds of lead.</p>
<p>We wanted to know whether these laws, adopted from 2003 to 2011, can keep up with the current generation of electronic products. To find out, we needed a better estimate of how much e-waste the U.S. now produces.</p>
<p>We mapped sales of electronic products from the <a href="https://www.theatlantic.com/technology/archive/2014/04/a-terminal-condition/361313/">1950s</a> to the present, using data from industry reports, government sources and consumer surveys. Then we <a href="https://doi.org/10.1038/s41597-020-0573-9">disassembled almost 100 devices</a>, from obsolete VCRs to today’s smartphones and fitness trackers, to weigh and measure the materials they contained.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=197&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=197&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=197&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=248&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=248&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374938/original/file-20201214-18-e30oa9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=248&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A researcher takes apart a smartphone to find out what materials are inside.</span>
<span class="attribution"><span class="source">Shahana Althaf</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374942/original/file-20201214-21-1eto45i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This dissected tablet shows the components inside, each of which were logged, weighed and measured by researchers.</span>
<span class="attribution"><span class="source">Callie Babbitt</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We created a <a href="https://doi.org/10.5281/zenodo.3986969">computer model to analyze the data</a>, producing one of the most detailed accounts of U.S. electronic product consumption and discards currently available.</p>
<h2>E-waste is leaner, but not necessarily greener</h2>
<p>The big surprise from our research was that U.S. households are <a href="https://doi.org/10.1111/jiec.13074">producing less e-waste</a>, thanks to compact product designs and digital innovation. For example, a smartphone serves as an all-in-one phone, camera, MP3 player and portable navigation system. Flat-panel TVs are about 50% lighter than <a href="https://archive.nytimes.com/www.nytimes.com/gwire/2009/06/15/15greenwire-some-see-e-waste-crisis-trailing-switch-to-dig-81110.html">large-tube TVs</a> and don’t contain any lead. </p>
<p>But not all innovations have been beneficial. To make lightweight products, manufacturers miniaturized components and glued parts together, making it harder to repair devices and more expensive to recycle them. <a href="https://doi.org/10.1007/s10098-020-01890-3">Lithium-ion batteries</a> pose another problem: They are hard to detect and remove, and they can spark <a href="https://www.theverge.com/2020/2/28/21156477/recycling-plants-fire-batteries-rechargeable-smartphone-lithium-ion">disastrous fires</a> during transportation or recycling.</p>
<p>Popular features that consumers love – speed, sharp images, responsive touch screens and long battery life – rely on metals like cobalt, indium and <a href="https://theconversation.com/what-are-rare-earths-crucial-elements-in-modern-technology-4-questions-answered-101364">rare-earth elements</a> that require immense energy and expense to mine. Commercial recycling technology cannot yet recover them profitably, although innovations are starting to emerge. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376830/original/file-20201231-49513-1tf9ypc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Apple’s new robot, Daisy, can disassemble nine different iPhone models to recover valuable materials that traditional recyclers cannot.</span>
<span class="attribution"><a class="source" href="https://www.apple.com/newsroom/2018/04/apple-adds-earth-day-donations-to-trade-in-and-recycling-program/">Apple</a></span>
</figcaption>
</figure>
<h2>Reenvisioning waste as a resource</h2>
<p>We believe solving these challenges requires a <a href="https://doi.org/10.1016/j.resconrec.2019.05.038">proactive approach</a> that treats digital discards as resources, not waste. Gold, silver, palladium and other valuable materials are now more concentrated in e-waste than in natural ores in the ground. </p>
<p>“<a href="https://www.bbc.com/future/article/20200407-urban-mining-how-your-home-may-be-a-gold-mine">Urban mining</a>,” in the form of recycling e-waste, could replace the need to dig up scarce metals, reducing environmental damage. It would also <a href="https://doi.org/10.1016/j.resconrec.2020.105248">reduce U.S. dependence</a> on <a href="https://www.cato.org/blog/chinas-critical-minerals-national-security-meaning-supply-chain-interdependence">minerals imported from other countries</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=245&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=245&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=245&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=308&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=308&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376714/original/file-20201228-17-1yhxq7y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=308&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Concentration of hazardous (left) and valuable (right) materials within the U.S. e-waste stream.</span>
<span class="attribution"><span class="source">Althaf et al. 2020</span></span>
</figcaption>
</figure>
<p>Government, industry and consumers all have roles to play. Progress will require designing products that are <a href="https://www.ifixit.com/">easier to repair</a> and reuse, and persuading consumers to <a href="https://earth911.com/eco-tech/ways-to-reuse-old-laptop/">keep their devices longer</a>. </p>
<p>We also see a need for responsive e-waste laws in place of today’s dated patchwork of state regulations. Establishing <a href="https://knowledge.wharton.upenn.edu/article/how-u-s-laws-do-and-dont-support-e-recycling-and-reuse/">convenient</a>, <a href="https://sustainableelectronics.org/recyclers">certified</a> <a href="https://e-stewards.org/">recycling locations</a> can keep more electronics out of landfills. With retooled operations, recyclers can recover more valuable materials from the e-waste stream. Steps like these can help balance our reliance on electronic devices with systems that better protect human health and the environment. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/147972/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Callie Babbitt receives funding from the National Science Foundation, the Consumer Technology Association, and the Staples Sustainable Innovation Lab.</span></em></p><p class="fine-print"><em><span>Shahana Althaf received funding from the National Science Foundation, the Consumer Technology Association, and the Staples Sustainable Innovation Lab.</span></em></p>Technical advances are reducing the volume of e-waste generated in the US as lighter, more compact products enter the market. But those goods can be harder to reuse and recycle.Callie Babbitt, Associate Professor of Sustainability, Rochester Institute of TechnologyShahana Althaf, Postdoctoral associate, Yale UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1194532019-10-03T11:42:05Z2019-10-03T11:42:05ZMining powers modern life, but can leave scarred lands and polluted waters behind<figure><img src="https://images.theconversation.com/files/294875/original/file-20190930-194862-sw5kbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Bingham Canyon open-pit copper mine in Utah has operated since 1903.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/cDu6xL">David Guthrie/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Modern society relies on metals like copper, gold and nickel for uses ranging from medicine to electronics. Most of these elements are rare in Earth’s crust, so mining them requires displacing vast volumes of dirt and rock. Hard rock mining – so called because it refers to excavating hard minerals, not softer materials like coal or tar sands – generated <a href="https://www.pwc.com/gx/en/mining/assets/pwc-mine-report-2018.pdf">US$600 billion in revenues worldwide in 2017</a>.</p>
<p>The Trump administration has revived several controversial mining proposals that previously were blocked or stalemated. They include the <a href="https://pebblepartnership.com/">Pebble Mine</a> at the headwaters of Alaska’s Bristol Bay and leasing around Minnesota’s <a href="https://www.mprnews.org/story/2018/09/06/boundary-waters-mining">Boundary Waters Canoe Area Wilderness</a>. It also approved a <a href="https://tucson.com/news/local/rosemont-mine-wins-final-permit-needed-for-construction/article_e3676d00-7297-5429-9854-a8816b75c639.html">large copper mine</a> in southern Arizona, which was subsequently <a href="https://news.azpm.org/p/news-features/2019/8/20/156855-exploring-the-legal-framework-behind-blocking-the-rosemont-mine/">blocked by a federal court ruling</a>.</p>
<p>I study human-altered landscapes, including areas impacted by mines. Mining operations are major water pollution sources and can cause problems that persist for generations. Their global footprints also directly reshape significant portions of Earth’s topography, leaving indelible evidence of human presence. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/LAlKq-kgCSE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The proposed Pebble Mine in Alaska sits at the headwaters of Bristol Bay, the world’s largest commercial sockeye salmon fishery.</span></figcaption>
</figure>
<h2>Digging deep and wide</h2>
<p>In most locations, concentrations of copper, gold and other elements are too low to be extracted profitably. But in some spots they occur in seams of mineable, high-concentration minerals called ores. The economically viable concentration of a mineral depends largely on its market price. Gold ore can be viable at concentrations as low as 0.0001%, while copper becomes uneconomic below 0.5%. </p>
<p>To reach these deposits underground, miners tunnel, dig open pits or scrape through the Earth’s surface. The choice of technique depends on factors including how consolidated the ore is, the geologic setting and the depth of the ore.</p>
<p>Deep mines disturb the smallest amount of surface land, but are inherently more dangerous for miners. Far below the Earth’s surface, crews constantly risk encountering toxic gas fumes or stale air with no life-giving oxygen. Other dangers include earthquakes and equipment failures. In 2010, 33 Chilean miners spent <a href="https://www.cnn.com/2013/07/13/world/americas/chilean-mine-rescue/index.html">over two months trapped underground</a> in a copper-gold mine after a ramp collapsed, but ultimately were rescued. </p>
<p>Growing international emphasis on mine safety and changes in technology and ore quality have prompted a shift from deep mining to pit mines or surface mines, which access ores from the open air. Pit mines can be up to three-quarters of a mile deep, but typically cover less than 20 square miles. In contrast, surface mines typically extend less than 1,000 feet into the Earth’s crust, but can extend over hundreds of square miles. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=444&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=444&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=444&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=558&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=558&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294878/original/file-20190930-194819-fp7ina.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=558&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Along with metals such as gold, silver and iron, mines also produce materials including sand and gravel, crushed stone and Portland cement.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/news/top-5-mineral-producing-states">USGS</a></span>
</figcaption>
</figure>
<h2>Acidic waters</h2>
<p>Accessing ore typically involves blowing apart bedrock, removing it from the shaft or pit and storing waste materials nearby after extracting the ore. In these heaps of loose rock, known as spoil piles, previously buried raw minerals are exposed to air or water. Sulfur-rich compounds in the rock react with oxygen and water, producing sulfuric acid, which can lower the pH of nearby streams to levels comparable to lemon juice or vinegar. </p>
<p>At its worst this process, known as <a href="https://www.colorado.edu/cwest/research/research-themes/water-and-environmental-quality/acid-minerock-drainage">acid mine drainage</a>, can kill most native aquatic life. If acid drainage reaches groundwater, it may persist for decades or centuries and start a cascade of other impacts that impair water quality throughout local river networks. </p>
<p>When acid mine drainage lowers a stream’s pH, other metals can also start to melt out of minerals in spoil piles, mine shafts or adjacent soils, leaching into soil and groundwater that intersects these areas. This creates waters with increased levels of cadmium, copper, lead and other heavy metals, which are harmful to aquatic insects, fish and human health. </p>
<p>These effects can be transported far downstream and last for generations. Old and abandoned mines around the world have harmed water quality <a href="https://theconversation.com/acid-drainage-the-global-environmental-crisis-youve-never-heard-of-83515">long after mining has ceased</a>. Their impacts can come as long-term slow leakage, or as sudden discharges like the <a href="https://www.denverpost.com/2019/02/20/colorado-mining-industry-water-pollution/">2015 Gold King spill</a> near Silverton, Colorado, which released three million gallons of mine wastewater and debris into the Animas River. </p>
<p>According to the U.S. Government Accountability Office, there are <a href="https://www.gao.gov/new.items/d11834t.pdf">at least 161,000 abandoned hardrock mining sites</a> in the U.S. West and Alaska. Of these, at least 33,000 have contaminated water supplies or left piles of mine waste contaminated with arsenic behind. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294880/original/file-20190930-194819-3b8rs.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">Water from the 2015 Gold King mine spill flows through retention ponds built to contain and filter out heavy metals and chemicals.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Mine-Waste-Spill/c85eda1005ed4e6c9564df151097053c/135/0">AP Photo/Brennan Linsley</a></span>
</figcaption>
</figure>
<h2>Altering the planet’s shape</h2>
<p>Mining operations have also left thousands of square miles of land altered. In some cases, particularly <a href="https://pubs.acs.org/doi/abs/10.1021/acs.est.5b04532">mountaintop removal mining</a>, entire land forms are <a href="http://mtm-explore.web.duke.edu">permanently reshaped</a>. For millennia the planet’s surface was configured by the slow geologic processes of wind and rain. In contrast, mining alters the very geology, topography, hydrology and ecology of sites within years or decades. </p>
<p>These earth-moving activities represent the kind of effect that has led many environmental scientists to argue that our planet has entered a new geologic epoch – <a href="https://theconversation.com/the-irony-of-the-anthropocene-people-dominate-a-planet-beyond-our-control-64948">the Anthropocene</a> – where human choices have a greater impact on the Earth than purely natural processes. Landscape evolution moves in very slow cycles, so these topographic and geologic impacts may last far longer than mining’s effects on water quality. And because geologic processes are slow, scientists don’t know how these landscapes will diverge or converge in their future evolution.</p>
<h2>Essential and scarce</h2>
<p>Like oil and gas producers, mining companies have to contend with the fact that <a href="https://pubs.usgs.gov/circ/2007/1294/reports/paper9.pdf">the products they seek are scarce</a>, and easily extractable pools have already been tapped, leading to decreases in <a href="https://doi.org/10.3390/resources5040036">ore quality</a>. But demand for these metals continues to grow. </p>
<p>Rapidly expanding green energy will require extracting vast quantities of <a href="https://theconversation.com/what-are-rare-earths-crucial-elements-in-modern-technology-4-questions-answered-101364">rare earth metals</a> to power <a href="https://www.windpowermonthly.com/article/1519221/rethinking-use-rare-earth-elements">wind turbines</a>, electric vehicle <a href="https://highenergytrading.com/why-we-need-cobalt-rare-earth-minerals-to-power-electric-cars/">batteries</a> and <a href="https://pubs.usgs.gov/circ/1365/">solar panels</a>. Cellphones, computers, camera lenses and other goods also contain these materials.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1176952768080355330"}"></div></p>
<p>Economic imperatives lead companies to continue to push for new mines, either in the U.S. or abroad, where <a href="http://dx.doi.org/10.1126/science.268.5215.1305">environmental controls may be weaker</a> And new projects are likely to move more rock, consume more energy and have longer-lasting impacts than those that preceded them.</p>
<p>Ensuring that mining operations are subject to effective oversight and long-term monitoring, and that companies are held accountable for environmental damages, is a long-term challenge wherever mining takes place. The best way to completely avoid the complications that come from mining more minerals is to reduce consumption of them, make mining processes more efficient and make it more economic to recycle industrial materials and <a href="https://www.recyclingtoday.com/article/rare-earth-metals-recycling/">rare earth metals</a>. </p>
<p>[ <em>You respect facts and expertise. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=yourespect">You can read us daily by subscribing to our newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/119453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Ross receives funding from the National Science Foundation and NASA.</span></em></p>The Trump administration is supporting new mines in Alaska and Minnesota that many opponents say could devastate sensitive areas around them.Matthew Ross, Assistant Professor of Water Quality, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1153672019-06-11T20:12:02Z2019-06-11T20:12:02ZSilver makes beautiful bling but it’s also good for keeping the bacterial bugs away<figure><img src="https://images.theconversation.com/files/278843/original/file-20190611-32321-k3juqs.jpg?ixlib=rb-1.1.0&rect=148%2C107%2C4940%2C3145&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Silver has been used to make jewellery for centuries but it's also good at killing bacteria and could be used in new antibiotics.</span> <span class="attribution"><span class="source">Shutterstock/Santi S</span></span></figcaption></figure><p><em>To mark the <a href="https://www.iypt2019.org/">International Year of the Periodic Table of Chemical Elements</a> we’re taking a look at some of the elements used by researchers in their work.</em></p>
<p><em>Today’s focus is silver, an element seen as a marker of second place – but this reputation is undeserved.</em></p>
<hr>
<p><a href="http://www.rsc.org/periodic-table/element/47/silver">Silver</a> has long played second fiddle to other elements. In sport, it is the symbol of second place, giving way to gold in the medals. In jewellery, airline frequent flyer programs and credit cards, silver is also topped by gold and platinum.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278825/original/file-20190611-32342-jp4knh.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">Hold that silver high! Proud medal winners from the Sochi Winter Olympics, 2014.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/andymiah/12515487734/">Flickr/Andy Miah</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>But in the world of useful elements, silver should be gold.</p>
<p>My interest in silver originated when growing up in Canada, searching through loose change for pre-1968 quarters (25 cents) that were made from 80% silver (currently worth at least <a href="https://www.ngccoin.com/price-guide/series-detail.aspx?MVDetailID=55&Series=Canada-Silver-Quarter">US$2.24 each</a>).</p>
<hr>
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<strong>
Read more:
<a href="https://theconversation.com/from-the-bronze-age-to-food-cans-heres-how-tin-changed-humanity-114195">From the bronze age to food cans, here's how tin changed humanity</a>
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<p>More recently, in my <a href="http://www.aidrc.org.au/mark-blaskovich">current scientific role fighting antimicrobial resistance</a>, my interest has been piqued by silver’s association with killing bacteria.</p>
<h2>The silver medical treatment</h2>
<p>Silver has a <a href="https://www.sciencedirect.com/science/article/pii/S0734975018300946" title="Silver bullets: A new lustre on an old antimicrobial agent">long history of antibacterial activity</a>. The Phoenicians lined clay vessels with silver to preserve liquids (around 1300BCE), the Persians and Greeks used silver containers to store drinking water (around 5000-300BCE) and Americans travelling west during the 1880s added silver coins into water barrels. </p>
<p>More recently, <a href="https://www.sciencedirect.com/science/article/pii/S0305417914003040" title="Silver in medicine: A brief history BC 335 to present">both American and Russian space programs have used ionic silver to purify water</a>, including <a href="https://www.space.news/2016-06-06-nasa-open-to-using-silver-treated-water-in-space-despite-fda-opposition.html">on the International Space Station</a>. </p>
<p>Colloidal silver, a suspension of very small nanoparticles of silver metal, has found widespread use as a popular home remedy for a range of ailments, but is often marketed with <a href="https://www.quackwatch.org/01QuackeryRelatedTopics/PhonyAds/silverad.html">dubious claims</a> and is <a href="https://nccih.nih.gov/health/colloidalsilver">not supported by the scientific community</a>.</p>
<p>Some <a href="https://www.purestcolloids.com/history-silver.php">websites claim</a> the use of silver cutlery and dinnerware by wealthy Europeans in the Middle Ages may have helped favour their survival during the bubonic plague, though evidence supporting this is scant.</p>
<p>On a related note, one version of the <a href="https://www.quora.com/How-did-the-term-Blue-Blood-come-about">origin of the term “blue blood”</a> to describe the wealthy is based on their use of silver dinnerware, with significant silver ion ingestion known to cause <a href="https://www.merriam-webster.com/medical/argyria">argyria</a>, or purple-grey skin.</p>
<p>Despite these nonscientific associations, silver has found widespread acceptance in the medical community for specific applications of its antibacterial properties. </p>
<h2>Silver for burns</h2>
<p>Silver nitrate solutions were found to prevent eye infections in newborns in the 1880s, and were still commonly used for this in the 1970s. Solutions were also used to treat burn injuries, leading to many scientific reports in the 1960s, such as a <a href="https://nyaspubs.onlinelibrary.wiley.com/doi/abs/10.1111/j.1749-6632.1968.tb14745.x" title="THE TREATMENT OF EXTENSIVE THERMAL BURNS WITH 0.5% SILVER NITRATE SOLUTION">1968 study on treating extensive thermal burns with 0.5% silver nitrate solution</a> that describes an apparent reduction in death. </p>
<p>Both 0.5% silver nitrate solution and 1% silver sulfadiazine cream are still used in burn care and are accompanied by new silver-based wound dressings. </p>
<p>The antimicrobial use of silver has crept into consumer products, such as <a href="https://www.elastoplast.com.au/products/wound-care/antibacterial-fabric-plaster">antibacterial bandages</a>, <a href="http://thefootshop.com.au/products/carnation-footcare-silversock-black.html">socks</a> and <a href="https://www.nivea.com.au/products/nivea-men-silver-protect-roll-on-deodorant-40058083072720031.html">deodorants</a>, and antibacterial coatings on a range of products such as <a href="https://www.samsung.com/in/support/home-appliances/how-does-silver-nano-coating-help/">refrigerators</a>. </p>
<p>While this may sound like a good idea, there are concerns that widespread use of silver could cause <a href="https://www.nursingtimes.net/clinical-archive/infection-control/bacterial-resistance-to-silver-based-antibiotics/201749.article">bacteria to become resistant</a>, not only to silver, but also to our important antibiotics.</p>
<p>It’s not known exactly how silver kills bacteria, <a href="https://www.sciencedirect.com/science/article/pii/S1549963415006000" title="Silver nanoparticles: A new view on mechanistic aspects on antimicrobial activity">but it seems to work by multiple mechanisms</a>, including cell membrane damage and free radical generation. </p>
<p>Our work on silver is looking at whether it can help existing antibiotics work more effectively, especially against resistant bacteria. This research, which has been ongoing for more than five years, has identified that there is better synergy between silver and some types of antibiotics than others, but we don’t yet know why. </p>
<p>Eventually, this research could lead to new formulations of antibiotics with better activity, where the actual antibiotic remains the same but it is delivered as a salt with silver, instead of a more common ion like sodium.</p>
<h2>The silver resources</h2>
<p>The actual word silver stems from the Anglo-Saxon name for it, siolfur, while its chemical symbol Ag comes from the Latin name for silver, argentum.</p>
<p>Silver can sometimes be found as nuggets of pure metal, though this form is more rare than gold. Most often it is found combined with other elements in ores such as argentite (with sulfur) or galena (with lead).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278823/original/file-20190611-32335-1ggjcxg.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">Not so shiny yet, a lump of silver ore.</span>
<span class="attribution"><span class="source">Shutterstock/hecke</span></span>
</figcaption>
</figure>
<p>The ores are mined and the silver generally removed by smelting (heating combined with chemical reactions). It is believed this technique was discovered before 2000BCE.</p>
<p>Historically, the major use of silver has been as coinage and in jewellery. Traditional photography uses silver halides for the photosensitive film, while mirror backings and Christmas ornaments use silver-plated glass.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/titanium-is-the-perfect-metal-to-make-replacement-human-body-parts-115361">Titanium is the perfect metal to make replacement human body parts</a>
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<p>Silver lies in the middle of the <a href="https://www.raci.org.au/periodic-table-on-show">periodic table</a>. It is encircled by other useful and well-known metals such as (clockwise from above) copper, zinc, cadmium, mercury, gold, platinum, palladium and nickel. </p>
<p>I would argue that silver shines brightly above its neighbours – it actually does, as it has the highest reflectivity of any metal – and also is the best at conducting electricity and heat.</p>
<p>So silver really does deserves top of the podium: a gold for silver!</p>
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<p><em>If you’re an academic researcher working with a particular element from the periodic table and have an interesting story to tell then why not <a href="https://theconversation.com/au/pitches">get in touch</a>.</em></p><img src="https://counter.theconversation.com/content/115367/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Blaskovich has received funding from government and industry to investigate the antimicrobial activity of silver in combination with other compounds.</span></em></p>For too long silver has been used to mark second best but this element deserves more recognition thanks to its antibacterial properties.Mark Blaskovich, Senior Research Officer, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/903092018-03-20T10:41:57Z2018-03-20T10:41:57ZSilver nanoparticles in clothing wash out – and may threaten human health and the environment<figure><img src="https://images.theconversation.com/files/210882/original/file-20180317-104673-s0ospm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are nanometals in your washing machine.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/editor/image/interior-real-laundry-room-washing-machine-706180492">Evgeny Atamanenko</a></span></figcaption></figure><p>Humans have known <a href="https://doi.org/10.1089/sur.2008.9941">since ancient times</a> that silver kills or stops the growth of many microorganisms. Hippocrates, the father of medicine, is said to have used silver preparations for treating ulcers and healing wounds. Until the introduction of antibiotics in the 1940s, colloidal silver (tiny particles suspended in a liquid) was a mainstay for treating burns, infected wounds and ulcers. Silver is still used today in wound dressings, in creams and as a coating on medical devices.</p>
<p><a href="https://www.nano.gov/timeline">Since the 1990s</a>, manufacturers have added silver nanoparticles to numerous consumer products to enhance their antibacterial and anti-odor properties. Examples include clothes, towels, undergarments, socks, toothpaste and soft toys. Nanoparticles are ultra-small particles, ranging from 1 to 100 nanometers in diameter – too small to see even with a microscope. According to <a href="http://www.nanotechproject.org/cpi/">a widely cited database</a>, about one-fourth of nanomaterial-based consumer products currently marketed in the United States contain nanosilver.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210883/original/file-20180317-104694-1hbpyb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Korean toothpaste containing nanosilver.</span>
<span class="attribution"><a class="source" href="http://www.nanotechproject.org/pressroom/photos/gallery/">Alex Parlini, Project on Emerging Nanotechnologies</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>Multiple <a href="http://dx.doi.org/10.1016/j.chemosphere.2012.04.063">studies</a> have reported that <a href="http://dx.doi.org/10.1021/nn502228w">nanosilver leaches out of textiles</a> when they are laundered. Research also reveals that nanosilver may be toxic to <a href="https://doi.org/10.1016/j.cca.2010.08.016">humans</a> and <a href="https://doi.org/10.1016/j.envpol.2013.11.014">aquatic and marine organisms</a>. Although it is widely used, little is understood about its fate or long-term <a href="https://doi.org/10.1016/j.jare.2017.10.008">toxic effects</a> in the environment.</p>
<p>We are developing ways to convert this potential ecological crisis into an opportunity by recovering pure silver nanoparticles, which have many industrial applications, from laundry wastewater. In a recently published study, we describe a <a href="https://doi.org/10.1021/acssuschemeng.7b02933">technique for silver recovery</a> and discuss the key technical challenges. Our approach tackles this problem at the source – in this case, individual washing machines. We believe that this strategy has great promise for getting newly identified contaminants out of wastewater.</p>
<h2>A textile silver lode</h2>
<p>Use of nanosilver in consumer products has steadily risen in the past decade. The market share of silver-based textiles rose from <a href="https://doi.org/10.1016/j.envint.2012.12.010">9 percent in 2004 to 25 percent in 2011</a>. </p>
<p><a href="http://dx.doi.org/10.1186/1743-8977-7-8">Several investigators</a> have <a href="http://dx.doi.org/10.1021/es7032718">measured the silver content of textiles</a> and found values ranging from <a href="http://dx.doi.org/10.1021/es9018332">0.009 to 21,600 milligrams of silver</a> per kilogram of textile. <a href="http://dx.doi.org/10.1021/acs.est.5b06043">Studies</a> show that the amount of silver leached in the wash solution depends on many factors, including interactions between detergent and other chemicals and how silver is attached to the textiles. </p>
<p>In humans, exposure to silver can harm liver cells, skin and lungs. Prolonged exposure or exposure to a large dose can cause a condition called <a href="https://doi.org/10.1016/j.cca.2010.08.016">Argyria</a>, in which the victim’s skin turns permanently bluish-gray. </p>
<p>Silver is toxic to many <a href="https://doi.org/10.1021/nn4044047">microbes</a> and aquatic organisms, including <a href="http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=DDODB@_2009_v5n1_23">zebra fish</a>, <a href="https://doi.org/10.1016/j.chemosphere.2012.05.063">rainbow trout</a> <a href="https://doi.org/10.1021/acs.est.5b03285">and zooplankton</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=307&fit=crop&dpr=1 754w, https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=307&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/203943/original/file-20180130-170422-1eo4mnw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=307&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Toxic effects of silver nanoparticles on zebra fish embryos.</span>
<span class="attribution"><a class="source" href="http://dx.doi.org/10.1088/0957-4484/19/25/255102">Asharani et al., 2008.</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Once silver goes down the drain and ends up at wastewater treatment plants, it can potentially <a href="https://doi.org/10.1016/j.jclepro.2014.03.037">harm bacterial treatment processes</a>, making them less efficient, and foul treatment equipment. More than 90 percent of silver nanoparticles released in wastewater end up in nutrient-rich <a href="https://doi.org/10.1021/es3041658">biosolids</a> left over at the end of sewage treatment, which often are used on land as agricultural fertilizers. </p>
<p>This poses multiple <a href="https://doi.org/10.1021/es204608d">risks</a>. If plants <a href="https://pubs.acs.org/doi/abs/10.1021/acssuschemeng.7b02058?src=recsys&journalCode=ascecg">take up</a> silver from soil, they could concentrate it and introduce it into the food chain. It also can leach into groundwater or wash into rivers via rainstorms or erosion. </p>
<h2>Treating laundry water at the source</h2>
<p>Our research shows that the most efficient way to remove silver from wastewater is by treating it in the washing machine. At this point silver concentrations are relatively high, and silver is initially released from treated clothing in a chemical form that is feasible to recover. </p>
<p>Once laundry washwater is piped to wastewater treatment plants and mixed with with sewage and water from other sources, silver concentrations <a href="https://doi.org/10.1021/es3041658">decrease significantly</a> and <a href="https://doi.org/10.1021/es204608d">can be converted into different chemical forms</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=214&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=214&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=214&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=269&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=269&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210884/original/file-20180317-104673-6hroas.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=269&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Deer Island Wastewater Treatment Plant, Boston, Massachusetts.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Deer_Island_Waste_Water_Treatment_Plant_aerial.jpg">Doc Searls</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>A bit of chemistry is helpful here. Our recovery method employs a widely used chemistry process called ion exchange. Ions are atoms or molecules that have an electrical charge. In ion exchange, a solid and a liquid are brought together and exchange ions with each other. </p>
<p>For example, household soaps do not lather well in “hard” water, which contains high levels of ions such as magnesium and calcium. Many home water filters use ion exchange to “soften” the water, replacing those materials with other ions that do not affect its properties in the same way. </p>
<p>For this process to work, the ions that switch places must both be either positively or negatively charged. Nanosilver is initially released from textiles as silver ion, which is a cation – an ion with a positive charge (hence the plus sign in its chemical symbol, Ag+).</p>
<p>Even at the source, removing silver from washwater is challenging. Silver concentrations in the wash solution are relatively low compared to other cations, such as calcium, that could interfere with the removal process. <a href="https://doi.org/10.1021/acs.est.5b02262">Detergent chemistry</a> complicates the picture further because some detergent components can potentially interact with silver. </p>
<p>To recover silver without picking up other chemicals, the recovery process must use materials that have a chemical affinity for silver. In a previous <a href="https://doi.org/10.1016/j.seppur.2016.11.076">study</a>, we described a potential solution: Using ion-exchange materials embedded with sulfur-based chemicals, which bind preferentially with silver.</p>
<p>In our new study, we passed washwater through an ion-exchange resin column and analyzed how each major detergent ingredient interacted with silver in the water and affected the resin’s ability to remove silver from the water. By manipulating process conditions such as pH, temperature and concentration of nonsilver cations, we were able to identify conditions that maximized silver recovery. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=692&fit=crop&dpr=1 600w, https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=692&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=692&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=870&fit=crop&dpr=1 754w, https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=870&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/203937/original/file-20180130-170429-1qri9qv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=870&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Schematic of the silver recovery process using ion-exchange resin.</span>
<span class="attribution"><span class="source">Tabish Nawaz</span></span>
</figcaption>
</figure>
<p>We found that pH and the levels of calcium ions (Ca2+) were critical factors. Higher levels of hydrogen or calcium ions bind up detergent ingredients and prevent them from interacting with silver ions, so the ion-exchange resin can remove the silver from the solution. We also found that some detergent ingredients – particularly bleaching and water-softening agents – made the ion-exchange resin work less efficiently. Depending on these conditions, we recovered between 20 percent and 99 percent of the silver in the washwater.</p>
<p>Our findings can spur research into alternative detergent formulations that improve silver recovery. They also show that ion-exchange technology can recover trace silver from washwater that contains high levels of detergent. </p>
<h2>The future of wastewater treatment</h2>
<p>Today wastewater is collected from multiple sources, such as homes and businesses, and piped over long distances to centralized wastewater treatment plants. But increasing <a href="https://doi.org/10.1016/j.scitotenv.2016.03.128">evidence</a> shows that these facilities are ill-equipped to keep newly identified contaminants out of the environment, since they use one common treatment scheme for many different waste streams.</p>
<p>We believe the future is in decentralized systems that can treat different types of wastewater with specific technologies designed specifically for the materials they contain. If wastewater from laundromats contains different contaminants than wastewater from restaurants, why treat them the same way?</p>
<p>Our approach is both more efficient and a more effective way to address new environmental problems – potentially through a step as simple as installing a specialized water treatment cartridge in your washing machine.</p><img src="https://counter.theconversation.com/content/90309/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 organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Many socks, towels and other textiles are treated with silver nanoparticles to kill germs and odors. When the silver washes out, it can pollute waterways. Two chemists propose a way to collect it from wastewater.Sukalyan Sengupta, Professor of Wastewater Treatment, UMass DartmouthTabish Nawaz, Doctoral Student, UMass DartmouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/831172017-08-30T07:36:31Z2017-08-30T07:36:31ZThe history of Real del Monte, Mexico’s little slice of Cornwall<figure><img src="https://images.theconversation.com/files/183640/original/file-20170828-12314-1if6izi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The central square of Real del Monte, Mexico.</span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/0/02/Parroquia_de_Nuestra_Se%C3%B1ora_de_la_Asunci%C3%B3n%2C_Real_del_Monte%2C_Hidalgo%2C_M%C3%A9xico%2C_2013-10-10%2C_DD_07.JPG">Diego Delso/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Sitting at an altitude of 2,700 metres, Real del Monte is a pretty town in the Mexican state of Hidalgo. But with its architecture, heritage of silver mining and meat pasties, it is also a little slice of Cornwall, a region in the southwest of England.</p>
<p>The silver mines surrounding Real del Monte were the source of more than half the silver produced during the 300 years that Spain rule Mexico (1521–1821). By 1824, however, they were in bad condition, and were bought by a group of English investors. </p>
<p>To get the mines working again, the investors formed the Company of the Gentlemen Adventurers in the Mines of Real del Monte, and recruited more than 130 miners and engineers from Cornwall. When they arrived a year later in Veracruz, some never got any further, falling victim to an outbreak of yellow fever. It took the others more than a year to reach Real del Monte, hauling their <a href="https://en.wikipedia.org/wiki/Cornish_engine">Cornish steam engines</a> through marshes and rainforests with the help of donkeys. The famous engines were used to drain the water in the Cornish mines and would do the same job in Mexico.</p>
<p>The mines in Pachuca and Real del Monte (officially Mineral del Monte since 1869) had long been flooded and badly needed modernising. These Cornish technicians and their machines were able to fulfil both requirements.</p>
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<p>The first wave of Cornish miners and engineers were <a href="http://news.bbc.co.uk/1/hi/programmes/from_our_own_correspondent/413689.stm">followed by many others</a>. In the 1830s and 1840s, up to 350 were working in the surrounding mines. They were recruited through family networks with most coming from the towns of Camborne, Redruth and Gwennap. While some eventually returned to England, others chose to remain in Mexico.</p>
<p>Francis Rule left Camborne in 1853 at age 17 and made his fortune in the Mexican mines. Known as <a href="https://projects.exeter.ac.uk/cornishlatin/Francisrule.htm">“El Rey de la Plata”</a> (the silver king), he was a benefactor of the neighbouring city of Pachuca, where he had an imposing clock-tower built that still <a href="https://commons.Wikimedia.org/wiki/File:Reloj_Monumental_,Pachuca_,Hidalgo_,M%C3%A9xico_,2013-10-10_,DD_02.JPG">stands in the main square</a>. At the beginning of the 20th century Rule also contributed to the construction of <a href="http://www.wikiwand.com/es/Iglesia_Metodista_del_Divino_Salvador_(Pachuca)">Pachuca’s Methodist church</a>, where worshippers are still numerous among the local population.</p>
<h2>A vibrant culture</h2>
<p>Today the industrial and cultural heritage inherited from these Cornish families is significant and much appreciated in the region. Many local residents are proud to have English surnames such as Rule or Ludlow, and <a href="https://fr.wikipedia.org/wiki/Cornish_pasty">Cornish pasties</a> are considered their “national” dish. To produce them, the men and women who crossed the Atlantic to work in the silver mines brought with them turnips, then unknown in Mexico. In the little streets of Pachuca and Real del Monte the “paste” shops are now numerous.</p>
<p>In 2009 the first Internacional Festival de Paste was held in Real del Monte, and two years later the <a href="http://museodelpaste.com/">Museo del Paste</a> – where visitors are invited to cook and taste the little meat pies – opened its doors. The Duchess of Cornwall and her husband, Prince Charles, <a href="http://www.telegraph.co.uk/news/uknews/prince-charles/11204378/Prince-Charles-and-the-Mexican-city-with-more-pasties-than-Cornwall.html">visited</a> in 2014.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182754/original/file-20170821-27211-h67vq4.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">At the international pastie festival in 2012.</span>
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<p>Other historical sites testify to both the industrial advances and architectural contributions of members of this English community. At the Acosta mine, which closed in 1985, the buildings’ architecture is in the style typical of Cornish mines. The engine house and the high chimneys offer an unexpected industrial landscape in this green and mountainous region.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182755/original/file-20170821-27207-1i7c3sp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Acosta mine.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3AMina_de_Acosta%2C_Real_del_Monte%2C_Hidalgo%2C_M%C3%A9xico%2C_2013-10-10%2C_DD_07.JPG">Diego Delso/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>In the mining towns, houses built during the 19th century, with their sloping roofs, recall those of the southwestern tip of England. Yet the Casa Rule – formerly the Rule family’s house and now Pachuca’s town hall – is in the French Renaissance style. Constructed by the successful and wealthy “Francisco” Rule, it was designed to impress.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182756/original/file-20170821-27163-nj9tyz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&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">The Casa Rule, in the French Renaissance style.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/f/f2/Casa_Rule.JPG">Lalo Armi/Wikimédia Commons</a></span>
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<p>On a hill overlooking Real del Monte, in what used to be the English quarter, is the magnificent Pantéo Inglès, or English cemetery. It was established on land offered by one of the managers of the mines, Thomas Straffon, who was the first Briton to arrive with his wife and their children. Of the 755 tombs, all oriented toward England, the oldest dates to 1834. The plot of John Vial is more recent. This young Englishman chose to leave Real del Monte to fight with his compatriots during World War I and died in the Somme in 1916.</p>
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<img alt="" src="https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=364&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=364&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=364&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=458&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=458&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182762/original/file-20170821-27201-1i4t6je.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=458&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">The English cemetery.</span>
<span class="attribution"><a class="source" href="http://de10.com.mx/vivir-bien/2014/10/28/el-misterioso-panteon-ingles-en-mineral-del-monte">de10.com</a></span>
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<p>The English also introduced football to Mexico. The first game was played in 1900 by the Cornish miners who founded the Pachuca Athletic Club, Mexico’s first football club. In the 1930s Alfred C. Crowle, who emigrated from Cornwall to work in the mines, became the <a href="http://archivo.eluniversal.com.mx/deportes/131646.html">manager of the Mexican national football team</a>.</p>
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<p>This rich and unusual legacy is sustained and promoted by the <a href="http://www.cornish-mexico.org.uk/">Cornish Mexican Cultural Society</a>, founded in 2008. <a href="https://thecornishlife.co.uk/twinned-towns-3-cornish-towns-surprising-sister-cities/">Redruth and Real del Monte became sister cities</a> the same year, and trade between the two regions is growing. Thanks to its quirky heritage, <a href="https://projects.exeter.ac.uk/cornishlatin/cornishinlatinamerica.ht">Mexico’s little Cornwall</a> is on the verge of becoming a tourist destination.</p><img src="https://counter.theconversation.com/content/83117/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Diana Cooper-Richet ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>In 1825, more than 130 Cornish miners and engineers landed in Mexico to work in the silver mines. Their legacy lives on.Diana Cooper-Richet, Chercheur au Centre d’histoire culturelle des sociétés contemporaines, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) – Université Paris-Saclay Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/709702017-01-09T12:12:27Z2017-01-09T12:12:27ZWhat happens to your gut if you eat the $2,000 New York pizza topped with gold?<figure><img src="https://images.theconversation.com/files/152114/original/image-20170109-23468-xjv5yg.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cock and bullion: the $2,000 pizza. </span> <span class="attribution"><span class="source">Industry Kitchen</span></span></figcaption></figure><p>A restaurant in the New York financial district <a href="http://www.maxim.com/entertainment/2000-dollar-gold-pizza-2017-1">is offering customers a pizza</a> priced at US$2,000 (£1,623). It is topped with caviar, stilton cheese and gold leaf, with each bite costing around US$50. </p>
<p>New York is usually the kind of place that sets trends, but pizzerias elsewhere have actually been making pizzas sparkle for a while. A takeaway pizza chain in London <a href="http://www.mirror.co.uk/news/weird-news/worlds-most-expensive-pizza-500-7395670">started offering</a> £500 pizzas a year ago, this time with added lobster, caviar and truffle oil; while a Glasgow restaurant <a href="http://www.dailyrecord.co.uk/business/business-news/savour-pleasures-classic-italian-food-3081571">attracted attention</a> by selling a gold leaf pizza on eBay. </p>
<p>Gold on food goes back a good deal further than that, however. The renowned Italian chef, Gualtiero Marchesi, <a href="https://www.finedininglovers.com/blog/food-drinks/marchesi-milanese-gold-risotto/">has been</a> topping his signature dish, risotto alla milanese, with a single leaf of gold for decades. And that too is recent when you reflect that the kitchens of the wealthy were <a href="https://books.google.co.uk/books?id=HectxYEZg0oC&pg=PA110&lpg=PA110&dq=%22gold+leaf%22+food+medieval&source=bl&ots=mB3ymFLK31&sig=YBWFZOikAbP__r2nmgGwbsWTKSc&hl=en&sa=X&ved=0ahUKEwj4lJ-i863RAhXCORoKHbaRDggQ6AEIUjAO#v=onepage&q=%22gold%20leaf%22%20food%20medieval&f=false">sprinkling</a> the precious metal on feast cuisine <a href="https://cornucaupia.com/deiaurum/wiki-gold-and-silver-leaf-edible-html/">during</a> medieval times. </p>
<p>There is a medieval liqueur still consumed today with gold flakes in it known as <a href="http://www.local-life.com/gdansk/articles/goldwasser">Goldwasser</a>. Gold leaf is <a href="http://www.ediblegold.co.uk">also used</a> on chocolates and even has an E number (<a href="http://www.ukfoodguide.net/e175.htm">E175</a>). Whatever else has changed over the years, swallowing gold has always been considered the highest form of decadence. But what happens when we put gold into the body? And are there any other metals we’d be better off shaving on to pizzas instead?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/152017/original/image-20170106-18662-hzyla2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Better than chicken nuggets.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/pic-340054991/stock-photo-superhero-pizza-man.html?src=ZSpgSF_i8bp_bygQHn3pYw-1-49">Luis Molinero</a></span>
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<h2>Eat your carats</h2>
<p>Gold is an inert metal and is therefore not degraded by the acid in our stomachs. It will travel the length of the intestinal system unchanged, passing out in your poo. Depending on the sewage treatment system, it will eventually be returned to the land or washed out to sea ready to be recycled again. It casts panning for gold in an entirely new light. </p>
<p>Other metals are generally not used for ostentatious displays of edible wealth, but one exception is silver. Silver can be beaten into a leaf similar to gold and is also approved for use as an additive (<a href="http://www.ukfoodguide.net/e174.htm">E174</a>) – so long as it is pure and in its non-ionic form, which is the one that can’t be absorbed by the body. </p>
<p>Even then it is easier to add other metals to silver than gold, so there is still the risk it can be contaminated with the likes of aluminium. This can reduce the body’s ability to absorb essential minerals such as zinc, calcium and iron (aluminium is not essential). This will cause deficiency symptoms as diverse as soft bones (calcium), tiredness (iron) and lack of smell (zinc). </p>
<p>You might think these minerals might therefore be just the thing for a pizza, so long as they are in the ionic form that the body needs. We tend not to notice them in our diet but they are ubiquitous in grains, fruit and vegetables as they are essential for plant growth, too. Meat and dairy products are particularly rich sources and we have a very efficient system of absorbing the minerals they contain. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=626&fit=crop&dpr=1 600w, https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=626&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=626&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=787&fit=crop&dpr=1 754w, https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=787&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/152016/original/image-20170106-18641-1v1lceu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=787&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chewy sandwich filling.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/pic-466277147/stock-photo-iron-nails-on-a-wooden-yellow-backgroundselective-focusvintage-tone.html?src=5bMDe08D-GqUYB0m8CN9YA-1-44">mansong suttakam</a></span>
</figcaption>
</figure>
<p>One reason we don’t see minerals grated on our foods, of course, is that they don’t give the same bling value. But they will also react with the acid in our stomachs and get absorbed, since they are not inert. Excessive amounts of minerals in the body can be toxic, since they get laid down in soft tissues such as the brain and kidneys. This causes severe pain and eventually death. </p>
<p>In normal circumstances the body avoids such horrors by only absorbing a percentage of the minerals in the foods we eat. But if you flood the system with a mineral by taking large quantities, it can cause an excessive intake. As well as the toxicity risk, excessive intake of one essential mineral can make the body struggle to properly absorb other essential minerals – the same risk as when you ingest non-essential minerals like aluminium. </p>
<p>The bottom line is about balance, as with most of nutrition. Since there’s plenty of these minerals in the foods we eat, there’s absolutely no need and much potential harm to be had from adding any extra to our meals – or from taking supplements we don’t need. </p>
<p>Better to stick to gold, which does nothing good or bad for health except perhaps a feeling of satisfaction – or regret if you see it twinkling as it disappears down the drain. And if you’ve more money than sense and you’re still hungry for more after that gold pizza, you could always ask your willing chef to throw in a few diamonds next time. They’re inert, too, albeit a little crunchy.</p><img src="https://counter.theconversation.com/content/70970/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marie-Ann Ha 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>On sale in New York for US$2,000. Don’t all rush at once.Marie-Ann Ha, Senior Lecturer in Nutrition, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/693622016-11-29T16:00:33Z2016-11-29T16:00:33ZIndia’s golden quest to tackle ‘black money’ and the lessons from a century ago<figure><img src="https://images.theconversation.com/files/147940/original/image-20161129-10973-4hikzo.jpg?ixlib=rb-1.1.0&rect=3%2C7%2C2496%2C1657&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-198009308/stock-photo-indian-jewelry-store-in-delhi.html?src=lhtk7-4BMnvxVQxWwTAR5g-1-91">Alexandra Lande/Shutterstock</a></span></figcaption></figure><p>The Indian government has been trying to reduce its citizen’s demand for imported gold through a number of means over the last few years. This is part of a <a href="https://www.ft.com/content/e52dab06-b093-11e6-a37c-f4a01f1b0fa1">wider crack down</a> on currency used in the black market, that included the withdrawal and replacement of its two largest denomination bank notes in early November. The strategy will likely have some unintended consequences if we take our cues from the events of 1910.</p>
<p>Indians’ famous love for gold has created serious and ongoing economic issues for the nation. In 2011, Australian investment bank Macquarie <a href="http://timesofindia.indiatimes.com/business/india-business/Households-hold-950bn-gold-in-India/articleshow/10987660.cms">estimated that 78%</a> of India’s household savings were held in gold. </p>
<p>In effect, this means that India has a dual currency system where people choose to save mostly in gold rather than rrupees. This is unlike any other major economy and begs the question: how do you wean a population off a precious metal? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147929/original/image-20161129-10973-6ooj3k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wedded to the metal?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/priyamn/7001697104/in/photolist-7cY6CB-bEHwBA-9kb9dj-93SWe5-q8mreM-aVF1Pc-aKDkoi-kL8PPH-aKDMGF-6PpEKY-8PVuLY-chvDw7-53xSrT-77nExM-dpo4vU-6PRGo-8nvdQt-4dbGK-4QWaNh-dJFaP-6svm7T-6szwry-9mae1S-8nvsye-6svn5g-zFnUp4-4Cdu5A-Hw1vzy-rpyxiB-rqsRrQ">Priyambada Nath/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Bling and Buy sale</h2>
<p>Building up savings in gold rather than deposits in a bank creates a permanent drag on India’s growth. This happens because the savings do not increase the available funds for lending within the banking system. One reason it is so difficult to put this gold to work as investment capital is <a href="http://www.gold.org/supply-and-demand/interactive-gold-market-charting">that 79%</a> of it is bought as jewellery, rather than bars or coins. </p>
<p>India is the world’s largest consumer of gold jewellery at nearly 700 tonnes in 2015 according to <a href="https://forms.thomsonreuters.com/gfms/">GFMS Gold Survey 2016</a>. However, it mines less than two tonnes of gold a year. This means India must import gold worth US$25 billion each year, pushing up their current account deficit and pulling down the value of the rupee. </p>
<p>In 2015, Prime Minister Narendra Modi’s government introduced a <a href="http://dea.gov.in/sites/default/files/SGB_201617_Series3.pdf">Sovereign Gold Bond</a> scheme which allowed gold holders to swap their gold for an interest bearing bond. At the end of the bond’s life investors would effectively be returned the same amount of gold. This move reduced the minimum amount of gold necessary to participate in such a scheme to <a href="http://www.firstpost.com/business/gold-bonds-are-a-clear-winner-but-high-chances-of-deposit-scheme-becoming-a-flop-show-2428174.html">two grammes</a>. As of November 2016, 14 tonnes of gold had been subscribed to the two gold bond issues, with another <a href="http://www.firstpost.com/business/gold-bonds-are-a-clear-winner-but-high-chances-of-deposit-scheme-becoming-a-flop-show-2428174.html">five tonnes</a> collected through the older gold monetisation scheme (which has a larger minimum deposit of 30 grams). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=503&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=503&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=503&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=633&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=633&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147934/original/image-20161129-10973-1wdcggu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=633&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bullion for you.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/bullionvault/3591747543/in/photolist-6toDpM-6tsMKb-yVLdU-yVLmE-9JXozk-daMpB7-9cTtaM-9Hb93C-CUBkDa-Dv8Toj-4JwPYp-yVL6g-tdrAwN-6kgYU4-oR8Z4F-yVKZG-6oeEc1-yVKEH-6tsNhb-sxZN9E-6toE8x-bHSmix-buXPuA-yVKMs-5HaEtQ-6tsLF3-tdCqbK-97aMsD-6toyNZ-6tsKKW-9MaLTw-tv5TaH-cQrPQq-dDq9hJ-bwjUhb-6tsLaC-6tsLwb-6toAUR-ednZbA-4U4esk-9tgBve-e2yHUe-9TptiU-6TGhzC-fNn8fS-9ZiiS5-dV3n1X-e2EmMU-6tS45a-dHxN4w">Bullion Vault/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>However, relative to India’s estimated privately held gold stock of 20,000 tonnes these deposits represent tiny amounts and it still doesn’t seem like a solution.</p>
<h2>Unintended consequences</h2>
<p>An alternative would be to permanently reduce gold imports. To that end, in 2013, the government started to increase import taxes on gold imports to 6%; this now stands at 10%. However, falling gold prices during that period meant that there was still a 12% increase in gold imports in 2015 as consumers snapped up what they saw as bargain prices. </p>
<p>And here is where we go back more than 100 years to see how this all worked out last time. You see, India has battled precious metals imports for quite some time. In 1910 the government of India increased the import tariffs on silver from 5% to 11%. A market report in 1912, by <a href="https://babel.hathitrust.org/cgi/pt?id=osu.32435063926844;view=1up;seq=257">Pixley & Abell</a>, a gold wholesaler, pointed to a 28% fall in silver demand in the Indian Bazaars in the three years following the increase. They attributed this to not just a fall in demand for silver due to tax increases, but also a substitution of gold for silver in people’s savings as gold became more attractive on a relative basis.</p>
<p>Between 1910 and 1930 net imports of silver in India fell from 98m ounces to 31m, according to British Geological Survey Reports. After this time India gradually became the world’s largest gold consumer, a position it finally lost to China in 2015. </p>
<p>And it seems a return to silver as a major investment for consumers in India may be on the cards. Following the recent import tax hikes for gold, 2015 saw Indian silver imports grow to almost 8,000 tonnes, 14% up on the previous 2014 record. At the same time, demand for gold jewellery, which accounts for 75% of all Indian gold demand, is down <a href="http://www.gold.org/supply-and-demand/gold-demand-trends/back-issues/gold-demand-trends-q3-2016/jewellery">30%</a> for the 12 months to the end of september 2016, according to the World Gold Council. This points to a possible shift back to silver as a more prominent investment in India. </p>
<p>Gold makes up the vast majority of Indian jewellery sales. But the graph below shows the rapid growth in silver jewellery demand in India, which is up over 600% in ten years, relative to marginal growth of only 25% in gold jewellery demand. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=453&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=453&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147450/original/image-20161124-15368-18owhry.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=453&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Growth in Indian Gold and Silver Jewellery Demand.</span>
<span class="attribution"><span class="source">Thomson Reuters GFMS Gold 2016 and Silver Survey 2016</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Of course silver is not the only precious metal investment option available. If investors want a more compact form of wealth, then platinum, worth 56 times more per ounce, might suit. But a swap to silver in India, as was the norm pre-World War I, seems more likely and could have a major effect on prices. For a sense of scale, the Indian gold Jewellery market in 2015 was worth US$25 billion, while the total world silver jewellery market <a href="https://forms.thomsonreuters.com/gfms/">was worth only US$3.5 billion</a>. </p>
<p>Even a small substitution from gold to silver would result in a massive increase in the price of silver. A 10% reallocation from gold jewellery investment to silver in India would nearly double world silver jewellery demand. Mines and other sources would not be able to fill the gap immediately; prices would rise, further fuelling demand and creating a new, shiny headache for those trying to marshal India’s unusual economy.</p><img src="https://counter.theconversation.com/content/69362/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fergal O'Connor 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>Problems occur when a country falls in love with gold, and silver might be about to get a boost from proposed solutions.Fergal O'Connor, Senior Lecturer in Finance, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/537542016-03-30T10:47:04Z2016-03-30T10:47:04ZSee how to spice guard your bird feed – and other nifty chemistry life hacks<figure><img src="https://images.theconversation.com/files/116649/original/image-20160329-13679-1t4hcfc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Chilli: not nice for mice.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=AEQQTGzm7GkwugUQY6aCTQ-2-80&clicksrc=download_btn_inline&id=378311680&size=medium_jpg&submit_jpg=">Shutterstock</a></span></figcaption></figure><p>We all love a life hack that makes our day a little cheaper and easier. And the neat tricks that iron out the niggles of life can come from some interesting places. There’s some cool chemistry loitering in your cupboards that can also be put to good daily use. Here’s how – in words and video.</p>
<p><strong>1) Clean your silver</strong></p>
<p>There are plenty of products out there for polishing up the silverware. But there’s actually no need to buy any of them – all you need is some aluminium foil and a little bicarbonate of soda (sodium hydrogen carbonate).</p>
<p>Simply add a tablespoon of bicarb and a few strips of foil to a cup of hot water. Then drop in your tarnished silver and leave it for a few minutes. Remove, rinse and hey presto … sparkling silver.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116650/original/image-20160329-13688-wxcmm3.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">Just add aluminium foil.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=aNJgamg5zghMnkJsEiMEKA-1-26&clicksrc=download_btn_inline&id=384421105&size=medium_jpg&submit_jpg=">Shutterstock</a></span>
</figcaption>
</figure>
<p>So <a href="http://www.compoundchem.com/2013/12/16/removing-tarnish-silver/">how does it work</a>? Well, the black tarnish is silver sulfide. It slowly accumulates as the silver reacts with sulfur in the atmosphere and food (don’t use silver spoons to eat eggs! The sulfur in them brings up the tarnish quick sharp). </p>
<p>Polishing your silver removes the tarnish to reveal the silver underneath, but that slowly wears away at the surface detail. It’s much better, then, to use the foil trick. The aluminium reacts with the silver sulfide to create aluminium sulfide, turning the tarnish back to silver. So unlike polishing, you don’t lose any of the precious metal.</p>
<p>So what’s the bicarb for? The foil is covered with a thin layer of aluminium hydroxide, which stops the aluminium metal reacting with the silver. The bicarb removes this layer and allows the foil to do its stuff.</p>
<p>You might also notice a faint rotten egg smell. That’s due to the aluminium sulfide going on to react with the water to produce stinky hydrogen sulfide gas. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Mwhyzi7hQxQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The four chemistry life hacks in action.</span></figcaption>
</figure>
<p><strong>2) Bounce your batteries</strong></p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=960&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=960&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=960&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1206&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1206&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116603/original/image-20160329-13709-wc2aw6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1206&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dead or alive?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=qJiXGvbi3SIKvfZp6PZhKQ-1-4&clicksrc=download_btn_inline&id=210644065&size=medium_jpg&submit_jpg=">Shutterstock</a></span>
</figcaption>
</figure>
<p>Want to know if all those old batteries in your kitchen drawer are fresh or flat? Simple, just drop them – <a href="https://theconversation.com/it-turns-out-theres-truth-to-dead-battery-bounce-after-all-38680">the old batteries will bounce</a>. Alkaline batteries contain two chambers, one houses manganese dioxide, the other a mixture of zinc and potassium hydroxide in the form of a gel. As the battery discharges, the gel slowly turns to a ceramic. And as every chef knows, ceramics bounce and jelly doesn’t. </p>
<p><strong>3) The great vinegar descaler</strong></p>
<p>No need to fork out for anything fancy to descale kettles. Plain old vinegar does the trick just as nicely. Simply fill your kettle with one part vinegar to two parts water. Boil it, let it cool, then rinse. </p>
<p>Limescale is largely calcium carbonate. Acetic acid (vinegar) reacts with the scale to produce water, carbon dioxide, calcium acetate (which is soluble so it can be rinsed away) and a clean kettle. Now, who’s for tea?</p>
<p><strong>4) Chilli bird feed</strong></p>
<p>Don’t worry, it’s not cruel. In fact, if you want to attract birds to your garden with some tempting feed but aren’t so keen on rodents getting a free lunch, it’s just the thing. You could, of course, buy an elaborately engineered, squirrel-proof bird feeder – but it’s far cheaper and easier to go down the chemistry route and spike the bird food with chilli powder. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=533&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=533&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=533&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=670&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=670&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116604/original/image-20160329-13706-1nerv2e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=670&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">Chilli is his friend.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=pp-same_artist-365861474-GEuImcIGh6ecuKOctHhPnw-3&clicksrc=download_btn_inline&id=364447970&size=medium_jpg&submit_jpg=">Shutterstock</a></span>
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<p>Chilli feels hot because it contains a chemical called <a href="https://theconversation.com/explainer-why-chilli-burns-and-milk-helps-soothe-the-pain-30162">capsaicin</a> which triggers your heat receptors, fooling you into feeling like your mouth is burning. Your body is so convinced you’re on fire it starts the normal inflammatory response it uses to mitigate burns. This is what causes all the swelling, sweating and general discomfort associated with spicy food, symptoms that can also be used to your garden’s advantage.</p>
<p>In nature, the chilli pepper produces capsaicin to repel pesky mammals and insects. Birds, however, are entirely immune to the spice’s effects. In fact, the chilli plant needs birds to eat the fruit and spread its seeds far and wide.</p>
<p>The upshot is that you can load up bird feed with as much chilli powder as you like and your avian visitors won’t feel a thing. Meanwhile, any roaming rodents won’t come back for a second bite.</p><img src="https://counter.theconversation.com/content/53754/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Lorch 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>Discover the chemical wonders in your kitchen cupboard.Mark Lorch, Professor of Science Communication and Chemistry, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/386952015-03-24T09:44:57Z2015-03-24T09:44:57ZSilver shines as antibacterial for medical implants<figure><img src="https://images.theconversation.com/files/75548/original/image-20150320-14609-1g7fel2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Silver can be an effective antibacterial when treated in special ways.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-79687003/stock-photo-ten-troy-ounce-bar-of-silver-on-reflective-black-table.html">Silver image via www.shutterstock.com.</a></span></figcaption></figure><p>There have been growing concerns in the global health care system about the eradication of pathogens in hospitals and other patient-care environments. Overuse of antibiotics and antimicrobial agents has contributed to the emergence of antibiotic-resistant superbugs – such as methicillin-resistant <em>Staphylococcus aureus</em> (<a href="http://www.cdc.gov/mrsa/">MRSA</a>) and vancomycin-resistant <em>Enterococcus</em> (<a href="http://www.cdc.gov/HAI/organisms/vre/vre.html">VRE</a>) – which are difficult to kill. Lower immunity of sick patients coupled with the escalating problem of antibiotic-resistant pathogens has driven <a href="http://www.cdc.gov/HAI/surveillance/">increased rates of infection</a> in hospital and surgical environments.</p>
<p>It’s become crucially important to find ways to control infection in these settings. My research has focused on ways we can do so using alternative antibacterial materials such as the heavy metal silver. I’ve been working on a technique that electrically activates silver to create an antimicrobial surface. We can use this technology to create touch-contact and work surfaces – for instance, door knobs, push plates, countertops – that would help control the transmission of infections, primarily in health care environments. And now we’re experimenting with using silver in medical implants. </p>
<h2>Silver takes the gold in fighting bacteria</h2>
<p>Silver has long been known for its antibacterial properties. A variety of medical products including ointments, bandages, surgical tools and catheters employ silver-based technologies to prevent or fight infection.</p>
<p>But just an inert lump of silver isn’t going to do much. To be effective, it must first ionize. Research has shown that it’s silver in its <a href="http://www.ncbi.nlm.nih.gov/pubmed/16766878">ionic (Ag+) and not elemental form</a> that is antibacterial. An atom of silver has a neutral charge; we need to ionize it – take away a negatively charged electron – to transform it into its positively charged ionic form. Silver-based antibacterial surfaces must release silver ions directly into the pathogenic environment to be effective.</p>
<p>Silver ions have antibacterial properties for a few reasons. They can interfere with with cell DNA and affect their ability to procreate. They can inhibit enzymes involved with respiration, essentially suffocating the bacteria cells. And they can react with sensitive thiol groups on bacterial proteins to destroy normal biological activity of the protein. The multi-modal activity also makes it difficult for bacteria to develop resistance in the same way they do to specific antibiotic medications.</p>
<h2>Taking silver to inner space</h2>
<p>Particularly with our aging population, the number of <a href="http://www.ncbi.nlm.nih.gov/pubmed/17403800">joint replacement surgeries</a> is growing in the US. And with more surgeries, the associated risks of infection go up too. Now <a href="http://www.ise.ncsu.edu/people/faculty/shirwaiker.php">my work</a> with my student George Tan is focused on taking the bacteria-fighting power of silver ions inside the body.</p>
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<a href="https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=346&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=346&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=346&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=435&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=435&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75549/original/image-20150320-14627-1wharxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=435&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">Schematic diagram of silver ions dispersing from the implant and fighting pathogens.</span>
<span class="attribution"><span class="source">Rohan Shirwaiker</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>We are engineering ways to apply a <a href="http://dx.doi.org/10.1002/wnan.1201">low-intensity electrical charge</a> to a silver-titanium orthopedic implant. Our technique releases silver ions that kill or neutralize bacteria on and around the implant. The power source, which could be a strong watch battery, can potentially be integrated into the implant design. The body’s own fluids act as a conducting medium between the titanium and silver, enabling the low-level electrical current necessary to create and release the silver ions into the environment which might contain pathogens. </p>
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<a href="https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=124&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=124&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=124&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=156&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=156&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75550/original/image-20150320-14595-1yci0ds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=156&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Clear zones around the implant’s silver electrodes show that it’s stopping pathogens from growing nearby.</span>
<span class="attribution"><span class="source">Rohan Shirwaiker</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>This technology has the potential to dramatically reduce infections which negatively affect patient health, quality of life and health care costs. Our <a href="http://dx.doi.org/10.1007/s10856-015-5382-x">in vitro lab testing</a> has shown a 99% decrease in bacteria growth on and around implants after 24 hours and an infection-free environment after 48 hours. </p>
<p>One of the engineering challenges is to precisely control the level of silver that is released so that no healthy cells are <a href="http://www.epa.gov/iris/subst/0099.htm">compromised</a>; silver can be toxic. In future, we may explore the possibility of a smartphone app to control the power source and the release of silver ions remotely. Perhaps we could also devise a way to track the biophysical activity around the implant area. Broad application of the system could result in a significant advancement in the fight against infection, with the potential to be incorporated into any type of surgical implant.</p>
<p>Infection continues to be a major complication associated with implantable devices. Although rates vary, an <a href="http://www.aaos.org/research/committee/ptsafety/PS_SE_2010.pdf">average annual infection</a> rate of approximately 5% (at least 100,000 cases/year) associated with orthopedic procedures involving fracture fixation devices and joint prostheses costs the US healthcare system over <a href="http://www.ncbi.nlm.nih.gov/pubmed/20376538">$1.5 billion</a> annually. Treatment may require surgical procedures including implant removal, debridement of infected tissue, implant replacement and 6–12 weeks of antimicrobial therapy. Innovations in silver microbial technology could eventually have a wide-ranging impact on patient outcomes as well as on the health of the medical economy.</p><img src="https://counter.theconversation.com/content/38695/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rohan Shirwaiker has previously received research funding from ArgentumCidalElectrics Inc., PA.</span></em></p>Joint replacement surgery comes with a big risk of infection. New implant technology that can release silver ions inside the body could help – and without increasing antibiotic resistance.Rohan Shirwaiker, Assistant Professor of Industrial and Systems Engineering, North Carolina State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/153102013-06-19T18:14:06Z2013-06-19T18:14:06ZSilver bullets kill bacteria, not werewolves or witches<figure><img src="https://images.theconversation.com/files/25850/original/7rddp79j-1371636675.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A microscopic version of this kills bacteria.</span> <span class="attribution"><span class="source">Ed Schipul</span></span></figcaption></figure><p>The use of silver in medicine is <a href="http://tse.colloidalsilverkillsviruses.com/pdf/history.pdf">as old as</a> western medicine itself. Hippocrates is known to have used it to treat ulcers and wounds, the Romans almost certainly knew of its healing properties, its use continued through the middle ages and up to the present day. In the antibiotic age, interest in silver may have waned a little. But with urgent need to fight antibiotic-resistant bacteria, there is resurgence in its uses.</p>
<p>The reason is that silver can kill bacteria selectively and, more importantly, bacteria are unable to develop resistance against it. Despite silver’s long medical history, we do not know how it operates.</p>
<p>A paper published today in the journal <a href="http://dx.doi.org/10.1126/scitranslmed.3006276">Science Translational Medicine</a> sheds some light on silver’s success against bacteria. The most important find is that silver – unlike most antibiotics – works in more than one way. This is perhaps why bacteria are not able to build resistance to silver. </p>
<p>Here is silver’s multi-pronged approach: first, silver sticks very strongly to sulfur, found in parts of proteins. These sulfur groups normally bond to each other in proteins, holding them together and keeping the protein folded up in its correct shape. But if silver interacts with sulfur then the protein cannot fold correctly, and thus it cannot do its job. Next silver interferes with how bacteria use iron. Iron is often held in the places it is needed by binding to sulfur. And since silver also interacts with sulfur it stops the iron doing so. Finally, silver causes bacteria to produce extremely toxic substances called reactive oxygen species. These go on to cause damage inside the cell, harming the DNA, proteins and even the membranes that surround cells.</p>
<p>The net result of this silver onslaught is bacteria with severely damaged defences. Most importantly the membranes and walls that surround it are leakier after the silver treatment. Once weakened, they are much more susceptible to conventional antibiotics. </p>
<p>James Collins, at Boston University, who led the research showed that with added silver, less antibiotic drug is needed to kill the bugs. A great result in itself, but it gets better. Silver also reverses antibiotic resistance of <em>E. coli</em> bacteria making them, once more, susceptible to tetracycline.</p>
<p>These experiments not only worked in a Petri dish. When silver was added to standard antibiotics such as gentamicin and vancomycin, Collins could treat <em>E. coli</em> infections in the bladder and abdomens of mice. Normally these drugs have little effect on <em>E. coli</em> infections because they are designed to attack a completely separate class of bacteria. </p>
<p>Bacteria are broadly classified into two groups called Gram-negative or Gram-positive. Gram-negatives have an extra cell membrane that protects the bacteria, which means that it is much more difficult for some antibiotics, such as gentamicin and vancomycin, to penetrate the cell. It seems that silver negates this advantage and allows even weaker drugs to do their jobs.</p>
<p>Finally, Collins showed that the mice themselves remain unharmed by silver. If he is able to repeat this work in humans, then he may actually have a “silver bullet” for antibiotic resistance.</p><img src="https://counter.theconversation.com/content/15310/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Lorch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The use of silver in medicine is as old as western medicine itself. Hippocrates is known to have used it to treat ulcers and wounds, the Romans almost certainly knew of its healing properties, its use…Mark Lorch, Professor of Science Communication and Chemistry, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/91462013-02-21T03:46:19Z2013-02-21T03:46:19ZExplainer: what are safe haven investments?<figure><img src="https://images.theconversation.com/files/14734/original/6bg7x6tc-1346211797.jpg?ixlib=rb-1.1.0&rect=7%2C143%2C980%2C778&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gold and silver are traditionally considered "safe havens".</span> <span class="attribution"><span class="source">Image sourced from shutterstock.com</span></span></figcaption></figure><p>Safe haven investments are investments that provide a low level of risk during periods of extreme economic uncertainty. </p>
<p>The problem is that a safe haven investment is a safe haven investment until it is no longer a safe haven investment. </p>
<p>There are a number of assets that are often said to fall within this class and these include US government bonds, gold and silver, and land and property. Even if you identify such an investment the most important decision that you face is to decide when to invest in these assets?</p>
<p>US government bonds provide a classic example. In this case, US government bonds carry <a href="http://www.publicdebt.treas.gov/">the guarantee of the US government</a> with respect to coupon and principal payments, “backed by the full faith and credit of the U.S. government”. </p>
<p>Most governments issue bonds to investors but they are not all the same in terms of risk. For example, the Russian government defaulted on its bonds in 2000. Indeed, it is surprising just how many countries, including Australia during the 1930s, have defaulted on their debt over the last 200 years. The concern about European debt default is not unique to 2012. </p>
<p>While US Government bonds draw on the power of the US Government for their continued existence there are other safe haven type investments that draw upon their physical value. These include gold and silver, land and property and other physical assets that, in some sense, remain intact regardless of the surrounding economic turmoil.</p>
<p>Yet, can investment in silver or gold actually be labelled riskless? The gold price is currently high though there have been long periods of time when the gold price languished around USD 300.00 to USD 400.00 per ounce. To buy gold at USD1600.00 per ounce might seem a safe thing to do at present. However, this might not seem so safe if the price of gold were to suddenly fall to USD 300.00 per ounce as it did in the early 1980s. Similar movements have been observed in silver prices.</p>
<p>Many individual Australian investors believe that investment in land and property is riskless. But there now exists a growing body of disaffected Australian investors burned by the recent failure of a range of property investment vehicles due to the global financial crisis. </p>
<p>The timing of investment into safe havens is perhaps the most difficult decision. Should you wait until the equity market bottoms and then sell your shares and invest in the safe haven asset? This may seem reasonable at the time, but the problem with his action is that it crystalizes your losses. </p>
<p>In the wake of the global financial crisis equities could rebound, as they have after each of the recent financial crises over the last 30 years. While the equity market may not rebound to its earlier highs, waiting 12 months before moving your wealth to a safe haven could reduce the loss suffered as a result of the crisis. </p>
<p>But the market rebound poses its own question; is it really necessary to incur considerable transaction costs to invest in an asset class with little return (US government bonds) or with considerable risk (gold and property) now that things have settled a little? </p>
<p>Whether or not to move towards safe haven assets really comes down to your own investment portfolio decisions, and whether you believe in the value of diversification. If you are well-diversified it is likely that your investment portfolio already has exposure to so called safe haven investments. </p>
<p>Why would you decide to move from a well-diversified portfolio to a concentrated portfolio of safe haven assets just because of uncertain economic conditions? The whole reason for diversifying is to ride out both the certain and the uncertain times.</p><img src="https://counter.theconversation.com/content/9146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Heaney has received funding from the ARC in the past though is not currently a chief investigator on an ARC project.</span></em></p>Safe haven investments are investments that provide a low level of risk during periods of extreme economic uncertainty. The problem is that a safe haven investment is a safe haven investment until it is…Richard Heaney, Winthrop Professor, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.