tag:theconversation.com,2011:/uk/topics/polonium-poisoning-7830/articlesPolonium poisoning – The Conversation2023-08-10T20:00:53Ztag:theconversation.com,2011:article/2104622023-08-10T20:00:53Z2023-08-10T20:00:53ZWhat’s in vapes? Toxins, heavy metals, maybe radioactive polonium<figure><img src="https://images.theconversation.com/files/541174/original/file-20230804-29-77kck2.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-girl-smokes-disposable-electronic-cigarette-1943062066">Shutterstock</a></span></figcaption></figure><p>If you asked me what’s in e-cigarettes, disposable vapes or e-liquids, my short answer would be “we don’t fully know”.</p>
<p>The huge and increasing range of products and flavours on the market, changes to ingredients when they are heated or interact with each other, and inadequate labelling make this a complicated question to answer.</p>
<p><a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev-anchem-061318-115329">Analytical chemistry</a>, including <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">my own team’s research</a>, gives some answers. But understanding the health impacts adds another level of complexity. E-cigarettes’ risk to health varies depending on <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.1c00070">many factors</a> including which device or flavours are used, and how people use them.</p>
<p>So vapers just don’t know what they’re inhaling and cannot be certain of the health impacts.</p>
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Read more:
<a href="https://theconversation.com/no-vapes-arent-95-less-harmful-than-cigarettes-heres-how-this-decade-old-myth-took-off-203039">No, vapes aren't 95% less harmful than cigarettes. Here's how this decade-old myth took off</a>
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<h2>What do we know?</h2>
<p>Despite these complexities, there are some consistencies between what different laboratories find.</p>
<p>Ingredients include nicotine, flavouring chemicals, and the liquids that carry them – primarily propylene glycol and glycerine.</p>
<p><a href="https://www.industrialchemicals.gov.au/sites/default/files/2020-08/Non-nicotine%20liquids%20for%20e-cigarette%20devices%20in%20Australia%20chemistry%20and%20health%20concerns%20%5BPDF%201.21%20MB%5D.pdf">Concerningly</a>, we also find volatile organic compounds, particulate matter and carcinogens (agents that can cause cancer), many of which we know are harmful. </p>
<p>Our <a href="https://www.mja.com.au/journal/2019/210/3/nicotine-and-other-potentially-harmful-compounds-nicotine-free-e-cigarette">previous</a> <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">research</a> also found 2-chlorophenol in about half of e-liquids users buy to top-up re-fillable e-cigarettes. This is one example of a chemical with no valid reason to be there. Globally, it’s <a href="https://pubchem.ncbi.nlm.nih.gov/compound/2-Chlorophenol#section=Hazard-Classes-and-Categories">classified</a> as “harmful if inhaled”. Its presence is likely due to contamination during manufacturing.</p>
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Read more:
<a href="https://theconversation.com/many-e-cigarette-vaping-liquids-contain-toxic-chemicals-new-australian-research-169615">Many e-cigarette vaping liquids contain toxic chemicals: new Australian research</a>
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<h2>How about polonium?</h2>
<p>One potential ingredient that has been in the news in recent weeks is radioactive polonium-210, the same substance used to <a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">assassinate</a> former Russian spy Alexander Litvinenko in 2006. The Queensland government is <a href="https://www.abc.net.au/news/2023-07-26/queensland-scientists-test-vapes-for-polonium-210/102564282">now testing</a> vapes for it.</p>
<p>Polonium-210 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9207432/">can be found</a> in traditional cigarettes and other tobacco products. That’s because tobacco plants <a href="https://www.science.org/doi/abs/10.1126/science.153.3738.880">absorb it</a> and other radioactive materials from the soil, air and high-phosphate fertiliser.</p>
<p>Whether polonium-210 is found in aerosols produced by e-cigarettes remains to be seen. Although it is feasible if the glycerine in e-liquids comes from plants and similar fertilisers are used to grow them.</p>
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Read more:
<a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">Litvinenko poisoning: polonium explained</a>
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<h2>It’s not just the ingredients</h2>
<p>Aside from their ingredients, the materials e-cigarette devices are made from can end up in our bodies.</p>
<p><a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP2175">Toxic metals</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP5686">related substances</a> such as arsenic, lead, chromium and nickel can be detected in both e-liquids and vapers’ urine, saliva and blood.</p>
<p>These substances can pose serious health risks (such as being carcinogenic). They can leach from several parts of an e-cigarette, including the heating coil, wires and soldered joints.</p>
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<a href="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful, disposable vapes on a blue background" src="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chemicals from the device itself can end up in our blood, urine and saliva.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-colorful-disposable-electronic-cigarettes-on-2065547126">Shutterstock</a></span>
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Read more:
<a href="https://theconversation.com/we-asked-over-700-teens-where-they-bought-their-vapes-heres-what-they-said-190669">We asked over 700 teens where they bought their vapes. Here's what they said</a>
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<h2>That’s not all</h2>
<p>The process of heating e-liquids to create an inhalable aerosol also changes their chemical make-up to produce <a href="https://pubs.acs.org/doi/10.1021/acs.chemrestox.9b00410">degradation</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">products</a>. </p>
<p>These include:</p>
<ul>
<li><p>formaldehyde (a substance used to embalm dead bodies)</p></li>
<li><p>acetaldehyde (a key substance that contributes to a hangover after drinking alcohol)</p></li>
<li><p>acrolein (used as a chemical weapon in the first world war and now used as a herbicide).</p></li>
</ul>
<p>These chemicals are <a href="https://www.mdpi.com/2305-6304/10/12/714">often detected</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129974">e-cigarette samples</a>. However due to different devices and how the samples are collected, the <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0249-x">levels measured</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">vary widely</a> between studies.</p>
<p>Often, the levels are very low, leading to proponents of vaping arguing e-cigarettes are far safer than tobacco smoking. </p>
<p>But this argument does not acknowledge that many e-cigarette users (particularly adolescents) <a href="https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-3-extent">were or are not cigarette smokers</a>, meaning a better comparison is between e-cigarette use and breathing “fresh” air. </p>
<p>An e-cigarette user is undoubtedly exposed to more toxins and harmful substances than a non-smoker. People who buy tobacco cigarettes are also confronted with a plethora of warnings about the hazards of smoking, while vapers generally are not.</p>
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Read more:
<a href="https://theconversation.com/sex-and-lies-are-used-to-sell-vapes-online-even-we-were-surprised-at-the-marketing-tactics-we-found-200446">Sex and lies are used to sell vapes online. Even we were surprised at the marketing tactics we found</a>
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<h2>How about labelling?</h2>
<p>This leads to another reason why it’s impossible to tell what is in vapes – the lack of information, including warnings, <a href="https://www.legislation.gov.au/Details/F2021L00595">on the label</a>.</p>
<p>Even if labels are present, they don’t always reflect what’s in the product. Nicotine concentration of e-liquids is often quite different to what is on the label, and “nicotine-free” e-liquids often <a href="https://journal.chestnet.org/article/S0012-3692(20)30134-3/fulltext">contain nicotine</a>.</p>
<p>Products are also labelled with generic flavour names such as “berry” or “tobacco”. But there is no way for a user to know what chemicals have been added to make those “berry” or “tobacco” flavours or the changes in these chemicals that may occur with heating and/or interacting with other ingredients and the device components. “Berry” <a href="https://tobaccocontrol.bmj.com/content/30/2/185">flavour</a> alone could be made from <a href="https://tobaccocontrol.bmj.com/content/tobaccocontrol/suppl/2020/02/10/tobaccocontrol-2019-055447.DC1/tobaccocontrol-2019-055447supp001_data_supplement.pdf">more than 35</a> different chemicals. </p>
<p>Flavouring chemicals may be “food grade” or classified as safe-to-eat. However mixing them into e-liquids, heating and inhaling them is a very different type of exposure, compared to eating them.</p>
<p>One example is benzaldehyde (an almond flavouring). When this is inhaled, it <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.9b00171">impairs</a> the <a href="https://www.sciencedirect.com/science/article/pii/S2214750023000380">immune function</a> of lung cells. This could potentially reduce a vaper’s ability to deal with other inhaled toxins, or respiratory infections. </p>
<p>Benzaldehyde is one of only <a href="https://www.legislation.gov.au/Details/F2021L00595">eight</a> banned e-liquid ingredients in Australia. The list is so short because we don’t have enough information on the health effects if inhaled of other flavouring chemicals, and their interactions with other e-liquid ingredients.</p>
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<h2>Where to next?</h2>
<p>For us to better assess the health risks of vapes, we need to learn more about:</p>
<ul>
<li><p>what happens when flavour chemicals are heated and inhaled</p></li>
<li><p>the interactions between different e-liquid ingredients</p></li>
<li><p>what other contaminants may be present in e-liquids</p></li>
<li><p>new, potentially harmful, substances in e-cigarettes.</p></li>
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<p>Finally, we need to know more about how people use e-cigarettes so we can better understand and quantify the health risks in the real world.</p><img src="https://counter.theconversation.com/content/210462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Larcombe has previously received funding for e-cigarette research from the National Health and Medical Research Council, Lung Foundation Australia, Minderoo Foundation, Health Department of Western Australia and Asthma Foundation of Western Australia. The funders played no role in the conduct of the research. He is also a member of the Australian Council on Smoking and Health (ACOSH).</span></em></p>It’s not just the ingredients we should be concerned about. The devices themselves release chemicals that end up in our blood and urine.Alexander Larcombe, Associate Professor and Head of Respiratory Environmental Health, Telethon Kids InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1456642020-09-09T16:52:57Z2020-09-09T16:52:57ZAlexei Navalny poisoning: what theatrical assassination attempts reveal about Vladimir Putin’s grip on power in Russia<p>Vladimir Putin’s intelligence and security organs have used a variety of lethal ways over the past few decades to dispatch those who oppose him or the Russian state – an increasingly difficult line to draw. These murders and attempted murders are often theatrical and laced with morbid messaging. The recent poisoning of Putin opponent Alexei Navalny <a href="https://www.bbc.com/news/world-europe-54002880">with the nerve agent Novichok</a> has again illustrated the Russian president’s willingness to sanction dramatic homicide as a tool of the state. </p>
<p>Putin’s prioritisation of <a href="https://www.tandfonline.com/doi/full/10.1080/02684527.2019.1573537">theatrical vengeance</a> – even at the expense of large-scale diplomatic reprisals and biting economic sanctions – reveals both the nature of his regime and his obsession with maintaining and projecting power.</p>
<p>Political assassination during Putin’s reign is in keeping with Soviet and Russian traditions, but the brazenness of the Navalny poisoning and its timing during the swelling <a href="https://www.bbc.com/news/world-europe-54068451">Belarus protests</a> shows both continuity and change. After Stalin’s death in 1953 the Politburo of the Communist Party, not a single person, was the embodiment of the state during the cold war. Putin has blurred and conflated such distinctions since he assumed power in 2000.</p>
<h2>Ruthlessness</h2>
<p>Like his Soviet forebears, Putin presides over a declining state in which power intermingles with corruption and <a href="https://us.macmillan.com/books/9781250119346">extrajudicial murder</a>. The attempted poisoning of former Russian military intelligence officer and British spy Sergei Skripal in 2018 first introduced Novichok into the British vernacular. Fellow Russian intelligence officer and British agent Alexander Litvinenko did not survive his poisoning in 2006 with Polonium-210 in a cup of tea. His murder, <a href="https://webarchive.nationalarchives.gov.uk/20160613090324/https://www.litvinenkoinquiry.org/report">according to the official British inquiry</a>, was “probably” approved by Putin personally.</p>
<p>Putin’s well of ruthlessness runs deep, and he has not hidden his willingness to engage in “wet affairs” – such as murders, kidnapping or sabotage. It would be self-defeating to keep his readiness for vengeance secret: it’s a message he wants those Russians who may get grassroots political inspiration from the protests over the border in Belarus to hear. </p>
<p>When asked about specific killings, Putin routinely evades such questions as deftly as a talented spy evades surveillance. But when speaking in general terms, Putin has been clear. <a href="https://www.globalsecurity.org/intell/world/russia/fsb-wet.htm">Globalsecurity.org</a> and others quoted the Russian leader as threatening that “traitors will kick the bucket, trust me”, after Skripal was released in a spy swap in 2010.</p>
<p>Given the melding of leader with state, Putin has increasingly characterised personal disloyalty as a threat to the Russian state. So although former intelligence turncoats are frequent targets of Putin’s vengeance, victims also include journalists and political rivals, particularly those who investigate, expose, and criticise corruption among Putin and his inner circle. Navalny’s apparently <a href="https://theconversation.com/alexei-navalny-suspected-poisoning-why-opposition-figure-stands-out-in-russian-politics-144836">effective efforts to organise legitimate opposition</a> through the ballot box would be intolerable for any autocrat who is unsure how to govern without complete control. </p>
<h2>Soviet poisoning playbook</h2>
<p>Although poisoning is arguably the most dramatic form of Russian state-sponsored murder, outspoken Putin critics have been assassinated with more pedestrian means: in politician <a href="https://www.bbc.com/news/world-europe-31669061">Boris Nemtsov’s case</a>, four bullets in the back in February 2015. Likewise, Russian investigative journalist Anna Politkovskaya <a href="https://www.theguardian.com/world/2016/oct/05/ten-years-putin-press-kremlin-grip-russia-media-tightens">was shot on October 7 2006</a> – also Putin’s birthday – in her Moscow apartment building. Such killings could be cynically attributed to unfortunate street crime in a case of implausible denial, but Novichok leaves no room for doubt.</p>
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Read more:
<a href="https://theconversation.com/novichok-how-are-victims-surviving-poisoning-145574">Novichok: how are victims surviving poisoning?</a>
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<p>Perceived enemies of the Russian state, like the Soviet Union before it, have met their ends in a dizzying variety of gruesome ways, but why does the fascination with poison endure? There are tactical and strategic considerations. An assassin cannot expect a clean getaway after shooting a pedestrian on Waterloo Bridge in London, but a puncture wound with a <a href="https://www.bbc.com/news/av/magazine-37376130">ricin-tipped umbrella</a> would suffice, as in the case of Bulgarian dissident Georgi Markov’s assassination by Soviet intelligence in 1978. </p>
<p>Today, Soviet-created Novichok has replaced <a href="https://theconversation.com/handle-with-care-the-worlds-five-deadliest-poisons-56089">ricin</a>. It offers the assassin advantages such as stealth and time for escape. It can be administered by exposure to everyday items such as doorknobs or tea. It appears in a sleepy city like Salisbury, as in the case of Skripal, or on Navalny’s flight from Siberia.</p>
<p>Additionally, a poison victim suffers, often publicly, yielding strategic effects. The photographs of the pitiable Litvinenko, hairless, gaunt, suffering in his hospital bed, grimly underscored the intended message. While any thug can murder with a gun, Soviet and subsequently Russian leaders have made assassination into a dramatic art form. The use of exotic poisons shows that confrontations with power are not a battle between two people, but rather bring the full resources of the state to bear against an individual, framing the situation as hopeless and futile. Poison evokes fear that you are never safe, never out of reach.</p>
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<h2>Choppy waters</h2>
<p>Putin is a standard-bearer, rather than a pioneer in the long history of Russian political assassination. Still, the brazenness of an unambiguous assassination attempt on a figure like Navalny, and the political circumstances in Minsk, matter. They can be interpreted as the act of a leader whose hand may be feeling unsteady on the rudder of the ship of state. </p>
<p>At the same time, however, <a href="https://theconversation.com/vladimir-putin-secures-constitutional-changes-allowing-him-to-rule-until-2036-what-this-means-for-russia-141103">recent Russian constitutional reforms</a> have erased any line between leader and the state, and may give Putin the confidence to deal even more harshly with opponents. But this expanded power has not offered more tools to deal with, or co-opt, the most vocal opponents. Those who cannot be bribed must be intimidated. Those who cannot be intimidated must be silenced. </p>
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Read more:
<a href="https://theconversation.com/belarus-what-role-could-russia-play-in-alexander-lukashenkos-future-144701">Belarus: what role could Russia play in Alexander Lukashenko's future?</a>
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<p>If Putin has successfully manipulated the political process to make himself president for life, the coronavirus has been less cooperative in bending to his will. Claims of a <a href="https://theconversation.com/russian-coronavirus-vaccine-results-have-been-published-heres-what-they-reveal-145636">successful COVID-19 vaccine</a> notwithstanding, Russia’s ineffective response to the pandemic has laid bare the inadequacy of the regime. With the economic consequences of the pandemic and the oil crisis, combined with general Russian <a href="https://theconversation.com/ahead-of-constitutional-reform-vote-two-thirds-of-young-russians-think-vladimir-putin-should-step-back-from-power-141306">Putin fatigue</a>, opposition to Putin is <a href="https://www.bloomberg.com/opinion/articles/2020-09-09/russia-elections-will-navalny-s-poisoning-spur-the-protest-vote">likely to expand</a>. </p>
<p>Given Putin’s apparent legal impunity, his need to distract from state failures and corruption, and disconcerting Belorussian anti-authoritarian protests on his doorstep, it’s hard to imagine Putin losing his taste for the loathsome theatre of political assassination.</p><img src="https://counter.theconversation.com/content/145664/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Frey does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment. This analysis does not represent any official United States Government or Department of Defense position. </span></em></p><p class="fine-print"><em><span>David Gioe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment. This analysis does not represent any official United States Government or Department of Defense position.
</span></em></p><p class="fine-print"><em><span>Michael S Goodman 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>Vladimir Putin is a standard-bearer, rather than a pioneer in the history of Soviet and Russian political assassination.Michael S Goodman, Professor of Intelligence and International Affairs, King's College LondonDavid Frey, Director Center Holocaust and Genocide Studies, United States Military Academy West PointDavid Gioe, Associate Professor of History, United States Military Academy West PointLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/535142016-01-21T11:50:23Z2016-01-21T11:50:23ZLitvinenko poisoning: polonium explained<figure><img src="https://images.theconversation.com/files/108864/original/image-20160121-9754-u1yg2t.jpg?ixlib=rb-1.1.0&rect=53%2C0%2C951%2C640&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Polonium is found naturally in uranium ore</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/radioactiverosca/6862869951/in/photolist-bss18Z-74EqwM-7X1Ctf-2vVkpu-8cojGg-BRguip-BNXQpL-BhKABH-ankEnr-8crVfL-8cs5CU-ano7ky-atboEb-ati1uT-atboq5-at8LCr-atbpaN-6A9vPB-6vprqz-47snbL-7Xfo1h-dwnaWo-8gK8FW-8JA7k7-DqF9E-qpkBr9-bx8d9i-bXbo54-ankp9t-Bgbxok-atkxnq-atkwqy-qrBHpr-athPhc-atkrt3-atkua3-athLq4-atkBHs-atbpVs-cuhvHf-ceMcPq-atbpHy-at8M7n-atbqn9-DqFnW-DqFjp-DqFfd-DqF4Z-DqF6C-DqF3K">Rui Costa/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>The murder of former Russian spy Alexander Litvinenko was one of the most high-profile assassinations of the decade. It particularly captured the public imagination because Litvinenko was <a href="http://www.telegraph.co.uk/news/uknews/law-and-order/11371940/Alexander-Litvinenko-was-poisoned-twice-with-polonium-210-inquiry-hears.html">killed using polonium-210</a>, a rare but deadly substance that was thought to have been slipped into Litvinenko’s tea. Now a UK public inquiry has <a href="http://www.theguardian.com/world/2016/jan/21/alexander-litvinenko-was-probably-murdered-on-personal-orders-of-putin">issued its findings</a> on the case. But what is polonium?</p>
<h2>Rare and radioactive</h2>
<p>Polonium is a radioactive element that occurs naturally in tiny amounts (which are harmless to us). It was <a href="http://www.nobelprize.org/nobel_prizes/themes/physics/curie/">discovered in 1898</a> by Marie Curie, during her research on pitchblende, an ore of uranium. It has the chemical symbol “Po” and Curie named it after Poland, her native country. If you look at a periodic table, you’ll find polonium at the bottom of the group headed by oxygen and sulfur.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=763&fit=crop&dpr=1 600w, https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=763&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=763&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=959&fit=crop&dpr=1 754w, https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=959&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/108865/original/image-20160121-9754-1h72kx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=959&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Marie Curie.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/Category:Marie_Curie#/media/File:Marie_Curie_(Nobel-Chem).jpg">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>There are around 30 different isotopes of polonium ranging in atomic mass from 194 to 218, only differing from each other in their neutron number. The important one is polonium-210, which happens to be the one discovered by Curie.</p>
<p>Uranium atoms slowly decay into other atoms, eventually ending up as lead but with polonium as one stop on the way. Because of this radioactive decay, polonium atoms are continually being formed and decomposed so the element does not naturally accumulate in any significant amount.</p>
<p>Although polonium-210 was first isolated from uranium ores, today it can be artificially made by bombarding atoms of the metal bismuth with neutrons. According to <a href="http://www.theguardian.com/world/2015/mar/11/substance-used-to-poison-litvinenko-could-only-have-come-from-russia-inquiry">an expert who testified</a> to the Litvinenko enquiry, only one place in the world had a polonium “production line” – a closed nuclear facility in Sarov, just under 500 miles south-east of Moscow – and the sample used in the murder was highly likely to have come from here.</p>
<h2>Highly toxic</h2>
<p>Polonium is one of the <a href="http://www.medicalnewstoday.com/articles/58088.php">most toxic substances</a> known. According to some sources, it is up to a <a href="https://books.google.co.uk/books?id=j-Xu07p3cKwC&pg=PA332&lpg=PA332&dq=polonium+trillion+times+toxic&source=bl&ots=luQYfE41Kl&sig=fXHD19Rt_O9qaHFJA4-XZn8s0A0&hl=en&sa=X&ved=0ahUKEwj38v3M1LrKAhUBnBQKHQPpA-8Q6AEIIzAB#v=onepage&q=polonium%20trillion%20times%20toxictrillion&f=false">trillion times</a> more toxic than hydrogen cyanide. It is radioactive because it emits alpha particles (helium ions). Because these are easily absorbed by other materials, even by a few thin sheets of paper or by a few centimetres of air, polonium has to be inside your body to damage you.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/108867/original/image-20160121-9766-bc4z6r.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">Polonium can be produced from bismuth.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/play4smee/3605159933/in/photolist-hotYTE-uoAsXs-vk8xa-uKWEd-fyjRFb-fyjRCq-fyjRyq-fyjRuu-zLpkH-zoEx8-tYALv-eiWpPC-eiWpN3-eiWpMY-eiQFrX-eiQFrR-ek23do-ek23cd-z7vCj-cqUg2f-Cz27p-9fC6DH-7HSSUu-5cViiR-47thP5-9iDk6f-kydBF6-ceLMJ5-ejVZ3z-4dD29X-ceLMYQ-ceLM1b-hucaBo-6uDAoL-6uzorT-6uDAa3-hUDyjb-fFd2P7-7vZHsp-fFdLHb-dbrK4B-rym5wk-fFdMAy-fEVrr2-4vPx1v-fFd1aG-8JPat2-bmMReq-xZdQj-zmkuJa">play4smee/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>It’s this radiation that has made minuscule traces of polonium useful in anti-static brushes, which are used to remove static charge from sensitive equipment. The fact that its alpha particles are so easily absorbed also make it hard to detect by radiation detectors such as Geiger counters, so polonium is probably easier to smuggle than some other lethal agents.</p>
<p>If polonium is known to have entered the body very recently, there is a <a href="http://www.tandfonline.com/doi/abs/10.1080/15563650902956431?journalCode=ictx20&">chance of removing it</a> by gastric aspiration (sucking out the stomach contents) or lavage (washing the stomach out with water). Chelating chemical agents, the sort that are used to treat heavy metal poisoning, can also remove polonium from the body if administered very quickly. But once it gets into the blood, it is likely to cause acute radiation syndrome and you will die of <a href="http://www.news-medical.net/news/2007/03/06/22431.aspx">multiple organ failure</a>.</p>
<h2>Effect on the body</h2>
<p>The alpha radiation breaks apart the chemical bonds in living cells, damages DNA and creates lots of very reactive free radical ions that can do further damage. <a href="http://iopscience.iop.org/article/10.1088/0952-4746/27/1/001/pdf">One specific result</a> is a reduction in your white blood cell count which, apart from anything else, can make you more susceptible to infection and requires blood and platelet transfusions.</p>
<p>The liver, kidneys, spleen and bone marrow are particular targets and are massively damaged by the alpha-radiation. The rapid damage to the gastrointestinal tract causes nausea and vomiting. Bone marrow failure can result in days. One other target is hair follicles, which is why Litvinenko lost his hair <a href="https://www.clintox.org/documents/WMDSIG/AACT-WMD-Death_Polonium.pdf">before he died</a>. </p>
<p>Alexander Litvinenko is not the first casualty of polonium. In 1956, Marie Curie’s scientist daughter <a href="http://www.rsc.org/diversity/175-faces/all-faces/irene-joliot-curie">Irène Joliot-Curie</a> died of leukaemia that she is believed to have contracted through exposure to polonium years before. There <a href="https://theconversation.com/what-we-could-learn-from-yasser-arafats-exhumation-11030">have also been claims</a> that Palestinian leader Yasser Arafat may have been exposed to it in a similar way to which Litvinenko was.</p><img src="https://counter.theconversation.com/content/53514/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Cotton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Polonium’s chemical properties made it the ideal secret weapon for the assassins of Alexander Litvinenko.Simon Cotton, Senior Lecturer in Chemistry, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/296192014-07-28T14:21:54Z2014-07-28T14:21:54ZThe five most poisonous substances: from polonium to mercury<figure><img src="https://images.theconversation.com/files/55034/original/jrdzqjkv-1406545923.jpg?ixlib=rb-1.1.0&rect=0%2C50%2C1000%2C615&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Feared for a good reason.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/36519775@N00/12360610135">viperskin</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>With the <a href="http://www.bbc.co.uk/news/uk-28416532">announcement</a> of an inquiry into the murder of Alexander Litvinenko, talk of poisons is back in the news. There are many articles with <a href="http://www.thelistcafe.com/top-10-worst-toxic-substances/">lists</a> of the most poisonous substances, which are often gathered based on their acute toxicity as measured by something called LD50. But acute toxicity is only one factor that needs to be considered, and relying solely on LD50 or similar measures is overly simplistic.</p>
<p>LD50 is a measure of the dose of a substance needed to kill half of a given population, usually of mice. It is usually measured in dosage needed per unit weight of the animal. This seems a cruel but objective way to quantify how deadly a given substance is, but overall toxicity is more complex than that.</p>
<p>Toxicologists are aware of the limitations of LD50, and for technical, ethical, and legal reasons, measuring that values in animals is increasingly less common. So here is a list of substances that are more poisonous than their LD50 values might indicate.</p>
<h2>1. <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1471-4159.2006.03965.x/abstract">Botulinum toxins</a></h2>
<p>Even though some of them are used in the cosmetic industry (including in botox), the botulinum family of neurotoxins includes the most toxic substances known to man. The LD50 values reported for these seven proteins are about 5 ng/kg (ng stands for nanogram, which is a billionth of a gram).</p>
<p>Non-lethal quantities injected into mice can paralyse the affected limb for as long as a month. The exquisite selectivity of these toxins for certain types of cells in the human body is remarkable, but also means that many species (including all invertebrates) are simply unaffected.</p>
<h2>2. <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1440-1681.2002.03740.x/abstract">Snake toxins</a></h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/55036/original/c994wbrz-1406546586.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&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="attribution"><a class="source" href="https://www.flickr.com/photos/visitflorida/9269015383">visitflorida</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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</figure>
<p>Like botulinum toxins, most snake venoms are a mixture of many proteins which are often neurotoxins with LD50s below 1 mg/kg. A crucial complication here, however, is the speed of activity. While some snake venoms may be highly potent, other, less potent venoms might kill faster. This is vital information. A potent but slow-acting venom might leave enough time to intervene, while a fast-acting poison with a lower LD50 might kill you before you can get help.</p>
<h2>3. <a href="http://www.atsdr.cdc.gov/spl/">Arsenic</a></h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/55037/original/c388k875-1406546783.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/55037/original/c388k875-1406546783.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">Skin lesions from arsenic poisoning.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ajc1/4111946599">ajc1</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Elemental arsenic has an LD50 of around 13 mg/kg – orders of magnitude higher than some of the substances on this list. Despite that, the Agency for Toxic Substances and Disease Registry gives it the top rank on its priority list of hazardous substances. </p>
<p>This highlights a key consideration – how common a substance is and how likely you are to be exposed to it. Ex-spies notwithstanding, your odds of being exposed to polonium or botulinum in lethal quantities are negligible. But chronic exposure to toxic metals is a real problem for many people around the world, and a simple measure of acute lethality such as LD50 simply cannot capture this.</p>
<h2>4. Polonium-210</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=316&fit=crop&dpr=1 600w, https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=316&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=316&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=397&fit=crop&dpr=1 754w, https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=397&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/55039/original/vc34zkrf-1406548326.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=397&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<span class="attribution"><a class="source" href="https://www.flickr.com/photos/lulazzo/3205855939">lulazzo</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>The radioisotope used to kill Alexander Litvinenko is extraordinarily toxic even in quantities less than a billionth of a gram. The LD50 of this compound is not a property of its chemistry. While other toxic metals such as mercury and arsenic kill through the interaction of the metal with the body, polonium kills by emitting radiation which shreds sensitive biomolecules, such as DNA, and kills cells. Its half-life – the time taken for half of the ingested material to decay – is about a month, leading to a slow death by radiation poisoning.</p>
<h2>5. <a href="http://www.nejm.org/doi/full/10.1056/NEJM200006153422405">Mercury</a></h2>
<p>The harmful effects of mercury are perhaps most famously exemplified by Lewis Carroll’s Mad Hatter, who was chronically exposed to mercury while plying his trade. But the toxicity of mercury is actually far more complicated, depending critically upon the kind of mercury involved. Organic and inorganic mercury compounds have different effects and hence LD50 values (which are typically between 1mg/kg and 100 mg/kg).</p>
<p>Pure mercury is considerably less toxic, as dramatically illustrated by the <a href="http://www.nejm.org/doi/full/10.1056/NEJM200006153422405">case of a dental worker</a> who attempted suicide by injecting the liquid element into her veins. Ten months later she was effectively symptom-free, despite having mercury distributed throughout her lungs.</p><img src="https://counter.theconversation.com/content/29619/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Bissette 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>With the announcement of an inquiry into the murder of Alexander Litvinenko, talk of poisons is back in the news. There are many articles with lists of the most poisonous substances, which are often gathered…Andrew Bissette, PhD student, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/199612013-11-07T05:58:09Z2013-11-07T05:58:09ZArafat may have been poisoned, but what is polonium?<figure><img src="https://images.theconversation.com/files/34655/original/mkcpfct7-1383801575.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nine years after his death, Yasser Arafat's remains have produced even more questions.</span> <span class="attribution"><span class="source">Magh</span></span></figcaption></figure><p>A Swiss <a href="http://www.aljazeera.com/investigations/killing-arafat/swiss-forensic-report-arafat-death-201311671255163780.html">forensic report</a> of the exhumed remains of ex-Palestinian leader <a href="http://en.wikipedia.org/wiki/Yasser_Arafat">Yasser Arafat</a> today suggests <a href="http://www.bbc.co.uk/news/world-middle-east-24838061">polonium poisoning</a> may have been the cause of death – but what is polonium, and why is it so deadly?</p>
<p>First, we need to understand the basics of radioactivity.</p>
<p>Radioactivity is the (term given to the) emission of certain particles or electromagnetic waves caused by the breakdown of nuclei in atoms. Elements can vary so they have different numbers of neutrons within their nuclei; these are called <a href="http://en.wikipedia.org/wiki/Isotope">isotopes</a>.</p>
<p>An isotope’s half-life is the time that it takes for half of the starting material in a sample to be converted, or decayed, into another product (after this time half of the starting material is gone). The radioactivity of a material is inversely proportional to the material’s half-life (if something has a long half-life, the amount of radiation it releases per second is lower).</p>
<h2>High radioactivity, high lethality</h2>
<p><a href="http://en.wikipedia.org/wiki/Polonium">Polonium</a> is a highly radioactive heavy metal. It is arguably the most lethal known material. Although it has some minor industrial uses it is best known for links with possible assassinations. It is also used to produce neutrons in the core of nuclear weapons.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=849&fit=crop&dpr=1 600w, https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=849&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=849&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/34658/original/nkpgws3v-1383802170.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Marie Curie.</span>
<span class="attribution"><span class="source">Nobel Foundation</span></span>
</figcaption>
</figure>
<p>Discovered by <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/1903/marie-curie-bio.html">Marie Curie</a>, the element was named after her home country of Poland. Polonium is element 84 in the periodic table, and all of its isotopes are radioactive. Their half-lives vary between a few millionths of a second to 103 years.</p>
<p>When polonium is discussed in the media, it is usually in the context of the polonium-210 isotope (<a href="http://www.iaea.org/Publications/Factsheets/English/polonium210.html"><sup>210</sup>Po</a>). This isotope has a half-life of 138 days, so while the material has very high radioactivity, it is stable enough to be transported (usually from a location with nuclear reactors or other high level scientific equipment).</p>
<p><sup>210</sup>Po has been suggested as a method of assassination. The two most famous suspected cases being KGB-agent-turned-journalist <a href="http://en.wikipedia.org/wiki/Alexander_Litvinenko">Alexander Litvinenko</a> in 2006 and – as mentioned above – Yasser Arafat. </p>
<p>As air reacts with alpha particles, the polonium must be ingested (or be injected) into the assassination target. In the case of Litvinenko it is alleged that was given to him in a cup of tea.</p>
<p>The 138-day half-life of <sup>210</sup>Po is short, so the element is very radioactive. While it has a melting point of 254°C, it is so radioactive that if you made 1g piece of <sup>210</sup>Po it would create so much heat it would melt itself. The liquid would appear to glow blue due to the interaction of the alpha particles with the surrounding air.</p>
<h2>Polonium’s effects</h2>
<p>The toxicity of radioactive materials is usually measured in terms of the radiation emitted and/or absorbed. However, to compare with more conventional toxins, the median lethal dose (<a href="http://en.wikipedia.org/wiki/Median_lethal_dose">LD50</a>) for <sup>210</sup>Po that is usually quoted is about 1μg, or one millionth of a gram.</p>
<p>That is one ten thousandth the dose of <a href="http://emedicine.medscape.com/article/831760-overview">VX</a> – the most potent nerve gas. </p>
<p>Contamination is treated in the same way as other heavy metal poisoning, with <a href="http://en.wikipedia.org/wiki/Chelation">chelating</a> agents that bind to the metal and make it more likely to be excreted. However, once a victim shows the symptoms of <sup>210</sup>Po poisoning, the effects are likely to be fatal.</p>
<p>The type of radiation is also a factor in how dangerous a material is. The radiation released by <sup>210</sup>Po is called an <a href="http://en.wikipedia.org/wiki/Polonium#Alpha_counting">alpha particle</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/34660/original/ghmssztt-1383802836.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Alpha decay.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>The alpha particle is a helium nucleus (two protons and two neutrons). This relatively large particle will not travel far through air and is stopped by a piece of paper. However, it pulls electrons out of other elements (ionising them). In turn, the ionised elements are highly reactive and able to undergo reactions that would not normally occur in a human body. </p>
<p>So unlike the image of radiation damaging DNA and causing cancer, alpha particles act more like a normal poison, but damaging many different biological systems rather than targeting one type of molecule.</p>
<p>The effects of polonium poisoning are effectively those of <a href="http://www.cancer.gov/cancertopics/coping/radiation-therapy-and-you/page8">acute radiation poisoning</a>. These occur within one day of exposure to a large dose of ionising radiation. The effects are all based on damage occurring to the body’s fast-growing cells:</p>
<ul>
<li>bone marrow – a drop in number of blood cells causing tiredness</li>
<li>gastrointestial cells – causing vomiting and nausea</li>
<li>follicular cells – causing hair loss.</li>
</ul>
<h2>Detecting polonium</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/34653/original/sbv29q39-1383801349.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">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Benjamin Deutsch</span></span>
</figcaption>
</figure>
<p>Due to polonium’s high radioactivity, it is usual to detect it by making use of the way it decays. The speed (energy) of alpha particles produced by radiation is specific to the isotope that emits them and leaves a kind of signature, with which the original isotope can be identified. </p>
<p>A sample of fluid suspected of containing polonium is dried onto a surface and the energy of the emitted particles is measured. The number of particles with a particular energy is directly proportional to the amount of that isotope in the sample.</p>
<p>The short half-life makes <sup>210</sup>Po very hard to study. It is particularly hard to look for the remains of <sup>210</sup>Po contamination once a significant amount of time has passed.</p>
<p>Measurement of ratios of stable breakdown products of the various isotopes of polonium could give some insight into if poisoning has occurred, but this depends on the initial composition of the polonium sample and it is susceptible to contamination.</p><img src="https://counter.theconversation.com/content/19961/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Boland has received funding from and collaborates with the Australian Nuclear Science and Technology Organisation.</span></em></p>A Swiss forensic report of the exhumed remains of ex-Palestinian leader Yasser Arafat today suggests polonium poisoning may have been the cause of death – but what is polonium, and why is it so deadly…Martin Boland, Research Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.