Editing Polonium (section)

==Biology and toxicity==

===Overview===
Polonium can be hazardous and has no biological role.<ref name="nbb" /> By mass, polonium-210 is around 250,000 times more toxic than [[hydrogen cyanide]] (the {{LD50}} for <sup>210</sup>Po is less than 1 [[microgram]] for an average adult (see below) compared with about 250 [[milligrams]] for hydrogen cyanide<ref>{{cite web| url = http://physchem.ox.ac.uk/MSDS/HY/hydrogen_cyanide.html | archive-url = https://archive.today/20020211054154/http://physchem.ox.ac.uk/MSDS/HY/hydrogen_cyanide.html | url-status = dead | archive-date = 2002-02-11 |title =Safety data for hydrogen cyanide|work= Physical & Theoretical Chemistry Lab, Oxford University}}</ref>). The main hazard is its intense radioactivity (as an alpha emitter), which makes it difficult to handle safely. Even in [[microgram]] amounts, handling <sup>210</sup>Po is extremely dangerous, requiring specialized equipment (a negative pressure alpha [[glove box]] equipped with high-performance filters), adequate monitoring, and strict handling procedures to avoid any contamination. Alpha particles emitted by polonium will damage organic tissue easily if polonium is ingested, inhaled, or absorbed, although they do not penetrate the [[epidermis (skin)|epidermis]] and hence are not hazardous as long as the alpha particles remain outside the body and do not come near the eyes, which are living tissue. Wearing chemically resistant and intact gloves is a mandatory precaution to avoid transcutaneous [[diffusion]] of polonium directly through the [[skin]]. Polonium delivered in concentrated [[nitric acid]] can easily diffuse through inadequate gloves (e.g., [[latex gloves]]) or the acid may damage the gloves.<ref>[[#Bagnall|Bagnall]], pp. 202–6</ref>

Polonium does not have toxic chemical properties.<ref>{{Cite web|url=https://www.medicalnewstoday.com/articles/58088.php|title=Polonium-210: Effects, symptoms, and diagnosis|website=Medical News Today|date=28 July 2017}}</ref>

It has been reported that some [[microbe]]s can [[Methylation|methylate]] polonium by the action of [[methylcobalamin]].<ref>{{cite journal |last1= Momoshima | first1 =N.|last2= Song | first2 = L. X.|last3= Osaki | first3 =S.|last4=Maeda | first4 =Y.| title = Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin | journal =Environ Sci Technol | date =2001 | volume =35 | issue = 15 | pages = 2956–2960 | doi = 10.1021/es001730| pmid =11478248| bibcode =2001EnST...35.2956M}}</ref><ref>
{{cite journal|last1= Momoshima | first1 =N.|last2= Song | first2 = L. X.|last3= Osaki | first3 =S.|last4=Maeda | first4 =Y.| title = Biologically induced Po emission from fresh water | journal =J Environ Radioact| date = 2002 | volume = 63| issue = 2| pages= 187–197 | doi =10.1016/S0265-931X(02)00028-0| pmid =12363270| bibcode =2002JEnvR..63..187M}}</ref> This is similar to the way in which [[mercury (element)|mercury]], [[selenium]], and [[tellurium]] are methylated in living things to create [[organometallic]] compounds. Studies investigating the metabolism of polonium-210 in rats have shown that only 0.002 to 0.009% of polonium-210 ingested is excreted as volatile polonium-210.<ref>{{cite journal |display-authors=4 |last1=Li |first1=Chunsheng |last2=Sadi |first2=Baki |last3=Wyatt |first3=Heather |last4=Bugden |first4=Michelle |last5=Priest |first5=Nicholas |last6=Wilkinson |first6=Diana |last7=Kramer |first7=Gary H. |date=2010 |title=Metabolism of <sup>210</sup>Po in rats: volatile <sup>210</sup>Po in excreta |journal=Radiation Protection Dosimetry |volume=140 |issue=2 |pages=158–162 |doi=10.1093/rpd/ncq047 |pmid=20159915}}</ref>

===Acute effects===
The [[median lethal dose]] (LD<sub>50</sub>) for acute radiation exposure is about 4.5&nbsp;[[Sievert|Sv]].<ref name="pnl">{{cite web| url = http://www.pnl.gov/main/publications/external/technical_reports/PNNL-14424.pdf |title =Health Impacts from Acute Radiation Exposure| access-date = 2009-05-05|work=Pacific Northwest National Laboratory}}</ref> The [[committed effective dose equivalent (CEDE)|committed effective dose equivalent]] <sup>210</sup>Po is 0.51&nbsp;μSv/[[Becquerel|Bq]] if ingested, and 2.5&nbsp;μSv/Bq if inhaled.<ref name="nsds">{{cite web| url = http://hpschapters.org/northcarolina/NSDS/210PoPDF.pdf |title =Nuclide Safety Data Sheet: Polonium–210| access-date = 2009-05-05|work=hpschapters.org}}</ref> A fatal 4.5&nbsp;Sv dose can be caused by ingesting {{convert|8.8|MBq|μCi|abbr=on}}, about 50&nbsp;[[nanogram]]s (ng), or inhaling {{convert|1.8|MBq|μCi|abbr=on}}, about 10&nbsp;ng. One gram of <sup>210</sup>Po could thus in theory poison 20&nbsp;million&nbsp;people, of whom 10&nbsp;million would die. The actual toxicity of <sup>210</sup>Po is lower than these estimates because radiation exposure that is spread out over several weeks (the [[biological half-life]] of polonium in humans is 30&nbsp;to 50&nbsp;days<ref>{{cite journal| osti =7162390 |title =Effective half-life of polonium in the human|author=Naimark, D.H.|date=1949-01-04|journal=Technical Report MLM-272/XAB, Mound Lab., Miamisburg, OH}}</ref>) is somewhat less damaging than an instantaneous dose. It has been estimated that a [[median lethal dose]] of <sup>210</sup>Po is {{convert|15|MBq|mCi}}, or 0.089&nbsp;micrograms (μg), still an extremely small amount.<ref name="nuclearweaponsarchive">{{cite web| url =http://nuclearweaponarchive.org/News/PoloniumPoison.html |title =Polonium Poisoning|author=Carey Sublette|date=2006-12-14| access-date = 2009-05-05}}</ref><ref>{{cite journal| display-authors = 4| last1 = Harrison |first1=J. |title =Polonium-210 as a poison| date = 2007 |journal = J. Radiol. Prot.| pmid = 17341802 |volume = 27| issue = 1 | doi = 10.1088/0952-4746/27/1/001| quote = The conclusion is reached that 0.1–0.3&nbsp;GBq or more absorbed to blood of an adult male is likely to be fatal within 1 month. This corresponds to ingestion of 1–3&nbsp;GBq or more, assuming 10% absorption to blood |bibcode = 2007JRP....27...17H| pages = 17–40| last2 = Leggett| first2 = Rich| last3 = Lloyd| first3 = David| last4 = Phipps| first4 = Alan| last5 = Scott| first5 = Bobby| s2cid = 27764788 }}</ref> For comparison, one grain of [[salt|table salt]] is about 0.06&nbsp;mg = 60&nbsp;μg.<ref>{{cite web|url=http://www.physlink.com/Education/AskExperts/ae342.cfm|title=Approximately how many atoms are in a grain of salt?|author=Yasar Safkan|website=PhysLink.com: Physics & Astronomy}}</ref>

===Long term (chronic) effects===
In addition to the acute effects, radiation exposure (both internal and external) carries a long-term risk of death from cancer of 5–10% per Sv.<ref name="pnl" /> The general population is exposed to small amounts of polonium as a [[radon]] daughter in indoor air; the isotopes <sup>214</sup>Po and <sup>218</sup>Po are thought to cause the majority<ref>{{cite book| title = Health Risks of Radon and Other Internally Deposited Alpha-Emitters: BEIR IV|isbn=978-0-309-03789-1|page =5|publisher=National Academy Press|date=1988}}</ref> of the estimated 15,000–22,000 lung cancer deaths in the US every year that have been attributed to indoor radon.<ref>{{cite book| url =http://newton.nap.edu/html/beir6/ | archive-url =https://web.archive.org/web/20060919054314/http://newton.nap.edu/html/beir6/ | archive-date =2006-09-19 |title = Health Effects of Exposure to Indoor Radon| publisher=National Academy Press|place=Washington|date=1999}}</ref> [[Tobacco smoking#Health risks of smoking|Tobacco smoking]] causes additional exposure to polonium.<ref>{{cite web| url =https://www.straightdope.com/21343841/does-smoking-organically-grown-tobacco-lower-the-chance-of-lung-cancer |title =The Straight Dope: Does smoking organically grown tobacco lower the chance of lung cancer?| access-date = 2020-10-11|date =2007-09-28}}</ref>

===Regulatory exposure limits and handling===
The maximum allowable body burden for ingested <sup>210</sup>Po is only {{convert|1.1|kBq|nCi|abbr=on}}, which is equivalent to a particle massing only 6.8 picograms.<ref>{{Cite journal |last1=Boryło |first1=Alicja |last2=Skwarzec |first2=Bogdan |last3=Wieczorek |first3=Jarosław |date=2022-02-10 |title=Sources of polonium <sup>210</sup>Po and radio-lead <sup>210</sup>Pb in human body in Poland |journal=International Journal of Environmental Research and Public Health |language=en |volume=19 |issue=4 |pages=1984 |doi=10.3390/ijerph19041984 |doi-access=free |issn=1660-4601 |pmc=8872270 |pmid=35206170}}</ref> The maximum permissible workplace concentration of airborne <sup>210</sup>Po is about 10&nbsp;Bq/m<sup>3</sup> ({{val|3|e=-10}}&nbsp;μCi/cm<sup>3</sup>).<ref>{{cite web |url = https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Polonium-210.html |title = Nuclear Regulatory Commission limits for <sup>210</sup>Po| date = 2008-12-12 |access-date = 2009-01-12 |publisher = U.S. NRC}}</ref> The target organs for polonium in humans are the [[spleen]] and [[liver]].<ref>{{cite web | url =http://www.pilgrimwatch.org/health1.html | title =PilgrimWatch – Pilgrim Nuclear – Health Impact | access-date =2009-05-05 | archive-url =https://web.archive.org/web/20090105192000/http://www.pilgrimwatch.org/health1.html | archive-date =2009-01-05 | url-status =dead }}</ref> As the spleen (150&nbsp;g) and the liver (1.3 to 3&nbsp;kg) are much smaller than the rest of the body, if the polonium is concentrated in these vital organs, it is a greater threat to life than the dose which would be suffered (on average) by the whole body if it were spread evenly throughout the body, in the same way as [[caesium]] or [[tritium]] (as T<sub>2</sub>O).<ref>{{cite journal| last1=Moroz|first1=B. B.| last2=Parfenov|first2=Yu. D.| year=1972| title=Metabolism and biological effects of polonium-210| journal=Atomic Energy Review| volume=10| issue=23| pages=175–232| url=https://inis.iaea.org/search/search.aspx?orig_q=RN:53061794}}</ref><ref>{{Cite journal |last1=Jefferson |first1=Robert D. |last2=Goans |first2=Ronald E. |last3=Blain |first3=Peter G. |last4=Thomas |first4=Simon H.L. |date=2009 |title=Diagnosis and treatment of polonium poisoning |url=http://www.tandfonline.com/doi/full/10.1080/15563650902956431 |journal=Clinical Toxicology |language=en |volume=47 |issue=5 |pages=379–392 |doi=10.1080/15563650902956431 |pmid=19492929 |issn=1556-3650}}</ref>

<sup>210</sup>Po is widely used in industry, and readily available with little regulation or restriction.<ref name="Zimmerman"/><ref>{{Cite journal|last1=Bastian|first1=R.K.|last2=Bachmaier|first2=J.T.|last3=Schmidt|first3=D.W.|last4=Salomon|first4=S.N.|last5=Jones|first5=A.|last6=Chiu|first6=W.A.|last7=Setlow|first7=L.W.|last8=Wolbarst|first8=A.W.|last9=Yu|first9=C.|date=2004-01-01|title=Radioactive Materials in Biosolids: National Survey, Dose Modeling & POTW Guidance|journal=Proceedings of the Water Environment Federation|volume=2004|issue=1|pages=777–803|doi=10.2175/193864704784343063|doi-broken-date=30 April 2025 | url=https://www.researchgate.net/publication/314571422}}</ref> In the US, a tracking system run by the Nuclear Regulatory Commission was implemented in 2007 to register purchases of more than {{convert|16|Ci}} of polonium-210 (enough to make up 5,000 lethal doses). The IAEA "is said to be considering tighter regulations&nbsp;... There is talk that it might tighten the polonium reporting requirement by a factor of 10, to {{convert|1.6|Ci}}."<ref name="Zimmerman">{{cite news |url=https://www.nytimes.com/2006/12/19/opinion/19zimmerman.html |title=Opinion: The Smoky Bomb Threat |access-date=2006-12-19 |newspaper=The New York Times |first=Peter D. |last=Zimmerman|date=2006-12-19}}</ref> As of 2013, this is still the only alpha emitting byproduct material available, as a NRC Exempt Quantity, which may be held without a radioactive material license.{{citation needed|date=September 2013}}

Polonium and its compounds must be handled with caution inside special alpha [[glove box]]es, equipped with [[HEPA]] filters and continuously maintained under depression to prevent the radioactive materials from leaking out. Gloves made of [[natural rubber]] ([[latex]]) do not properly withstand chemical attacks, a.o. by concentrated [[nitric acid]] {{nowrap|(e.g., 6 M {{chem2|HNO3}})}} commonly used to keep polonium in [[Solution (chemistry)|solution]] while minimizing its [[sorption]] onto glass. They do not provide sufficient protection against the contamination from polonium ([[diffusion]] of <sup>210</sup>Po solution through the intact latex membrane, or worse, direct contact through tiny holes and cracks produced when the latex begins to suffer degradation by acids or UV from ambient light); additional surgical gloves are necessary (inside the glovebox to protect the main gloves when handling strong acids and bases, and also from outside to protect the operator hands against <sup>210</sup>Po contamination from diffusion, or direct contact through glove defects). Chemically more resistant, and also denser, [[neoprene]] and butyl gloves shield alpha particles emitted by polonium better than natural rubber.<ref>[[#Bagnall|Bagnall]], p. 204.</ref> The use of natural rubber gloves is not recommended for handling <sup>210</sup>Po solutions.

===Cases of poisoning===
Despite the element's highly hazardous properties, circumstances in which polonium poisoning can occur are rare. Its extreme scarcity in nature,<ref>{{Cite journal |last1=Hussain |first1=N. |last2=Ferdelman |first2=T. G. |last3=Church |first3=T. M. |last4=Luther |first4=George W. |date=1995 |title=Bio-volatilization of polonium: Results from laboratory analyses |url=https://www.researchgate.net/publication/226970567 |journal=Aquatic Geochemistry |language=en |volume=1 |issue=2 |pages=175–188 |doi=10.1007/BF00702890 |bibcode=1995AqGeo...1..175H |issn=1380-6165}}</ref> the short half-lives of all its isotopes, the specialised facilities and equipment needed to obtain any significant quantity, and safety precautions against laboratory accidents all make harmful exposure events unlikely. As such, only a handful of cases of radiation poisoning specifically attributable to polonium exposure have been confirmed.<ref>{{Cite journal |last1=Nathwani |first1=Amit C |last2=Down |first2=James F |last3=Goldstone |first3=John |last4=Yassin |first4=James |last5=Dargan |first5=Paul I |last6=Virchis |first6=Andres |last7=Gent |first7=Nick |last8=Lloyd |first8=David |last9=Harrison |first9=John D |date=2016 |title=Polonium-210 poisoning: a first-hand account |url=https://linkinghub.elsevier.com/retrieve/pii/S0140673616001446 |journal=The Lancet |language=en |volume=388 |issue=10049 |pages=1075–1080 |doi=10.1016/S0140-6736(16)00144-6|pmid=27461439 }}</ref>

====20th century====
In response to concerns about the risks of occupational polonium exposure, quantities of <sup>210</sup>Po were administered to five human volunteers at the University of Rochester from 1944 to 1947, in order to study its biological behaviour. These studies were funded by the [[Manhattan Project]] and the AEC. Four men and a woman participated, all suffering from terminal cancers, and ranged in age from their early thirties to early forties; all were chosen because experimenters wanted subjects who had not been exposed to polonium either through work or accident.<ref name="Rochester">{{cite journal |last1=Moss |first1=William |last2=Eckhardt |first2=Roger |date=1995 |title=The human plutonium injection experiments |url=https://fas.org/sgp/othergov/doe/lanl/pubs/00326640.pdf |journal=Los Alamos Science |volume=23 |pages=177–233}}</ref> <sup>210</sup>Po was injected into four hospitalised patients, and orally given to a fifth. None of the administered doses (all ranging from 0.17 to 0.30 μ[[Curie (unit)|Ci]] kg<sup>−1</sup>) approached fatal quantities.<ref>{{cite book |last=Fink |first=Robert |date=1950 |title=Biological studies with polonium, radium, and plutonium |publisher=McGraw-Hill |series=National Nuclear Energy Series |volume=VI-3 |isbn=5-86656-114-X |language=ru}}</ref><ref name="Rochester" />

The first documented death directly resulting from polonium poisoning occurred in the [[Soviet Union]], on 10 July 1954.<ref name="Gasteva">{{cite book |last=Gasteva |first=G. N. |date=2001 |editor-last=Ilʹin |editor-first=L. A. |title=Radiacionnaja medicina: rukovodstvo dlja vračej-issledovatelej i organizatorov zdravooxranenija, Tom 2 (Radiacionnye poraženija čeloveka) |trans-title=Radiation medicine: a guide for medical researchers and healthcare managers, Volume 2 (Radiation damage to humans) |publisher=IzdAT |pages=99–107 |chapter=Ostraja lučevaja boleznʹ ot postuplenija v organizm polonija |trans-chapter=Acute radiation sickness by ingestion of polonium into the body |isbn=5-86656-114-X |language=ru}}</ref><ref>{{cite journal |last1=Harrison |first1=John |last2=Leggett |first2=Rich |last3=Lloyd |first3=David |last4=Phipps |first4=Alan |last5=Scott |first5=Bobby |date=2 March 2007 |title=Polonium-210 as a poison |journal=Journal of Radiological Protection |volume=27 |issue=1 |pages=17–40 |doi=10.1088/0952-4746/27/1/001|pmid=17341802 |bibcode=2007JRP....27...17H |s2cid=27764788 }}</ref> An unidentified 41-year-old man presented for medical treatment on 29 June, with severe vomiting and fever; the previous day, he had been working for five hours in an area in which, unknown to him, a capsule containing <sup>210</sup>Po had depressurised and begun to disperse in aerosol form. Over this period, his total intake of airborne <sup>210</sup>Po was estimated at 0.11 GBq (almost 25 times the estimated LD<sub>50</sub> by inhalation of 4.5 MBq). Despite treatment, his condition continued to worsen and he died 13 days after the exposure event.<ref name="Gasteva" />

From 1955 to 1957 the [[Windscale Piles]] had been releasing polonium-210. The [[Windscale fire]] brought the need for testing of the land downwind for radioactive material contamination, and this is how it was found. An estimate of 8.8 terabecquerels (240 Ci) of polonium-210 has been made.

It has also been suggested that [[Irène Joliot-Curie]]'s 1956 death from leukaemia was owed to the radiation effects of polonium. She was accidentally exposed in 1946 when a sealed capsule of the element exploded on her laboratory bench.<ref>{{cite news|url=http://www.news.com.au/dailytelegraph/story/0,22049,20863878-5001031,00.html |title=Innocent chemical a killer |publisher=The Daily Telegraph (Australia) |date=2006-12-04 |access-date=2009-05-05 |first=Jeremy |last=Manier |url-status=dead |archive-url=https://web.archive.org/web/20090106013604/http://www.news.com.au/dailytelegraph/story/0,22049,20863878-5001031,00.html |archive-date=January 6, 2009 }}</ref>

As well, several deaths in Israel during 1957–1969 have been alleged to have resulted from <sup>210</sup>Po exposure.<ref>{{cite book|last = Karpin|first = Michael|title = The bomb in the basement: How Israel went nuclear and what that means for the world|publisher = Simon and Schuster|date = 2006|isbn = 978-0-7432-6594-2|url = https://archive.org/details/bombinbasementho00karp}}</ref> A leak was discovered at a [[Weizmann Institute]] laboratory in 1957. Traces of <sup>210</sup>Po were found on the hands of Professor Dror Sadeh, a physicist who researched radioactive materials. Medical tests indicated no harm, but the tests did not include bone marrow. Sadeh, one of his students, and two colleagues died from various [[cancer]]s over the subsequent few years. The issue was investigated secretly, but there was never any formal admission of a connection between the leak and the deaths.<ref name='LA Times 2007-01-01'>{{cite news |first=Thomas |last=Maugh |author2=Karen Kaplan |title=A restless killer radiates intrigue |date=2007-01-01|url =https://www.latimes.com/archives/la-xpm-2007-jan-01-sci-polonium1-story.html |work =Los Angeles Times |access-date = 2008-09-17}}</ref>

The [[Church Rock uranium mill spill]] 16 July 1979 is reported to have released [[polonium-210]]. The report states animals had higher concentrations of lead-210, polonium-210 and radium-226 than the tissues from control animals.<ref name="Millard1983">{{cite web | author= Jere Millard, Bruce Gallaher, David Baggett, Steven Gary | date=September 1983 | title=The Church Rock uranium mill tailings spill a health and environmental assessment, page 32 | url=https://semspub.epa.gov/work/06/1000720.pdf | access-date=2024-01-30}}</ref>

====21st century====
{{Further|Poisoning of Alexander Litvinenko|Cause of Yasser Arafat's death}}
The cause of the [[Poisoning of Alexander Litvinenko|2006 death]] of [[Alexander Litvinenko]], a former Russian [[Federal Security Service|FSB]] agent who had defected to the United Kingdom in 2001, was identified to be poisoning with a lethal dose of <sup>210</sup>Po;<ref>{{cite news |title=The mystery of Litvinenko's death |url=http://news.bbc.co.uk/1/hi/uk/6180432.stm |date=2006-11-24 |work=BBC News |first=Tom |last=Geoghegan}}</ref><ref name="bbc">{{cite news| url =http://news.bbc.co.uk/1/hi/uk/6698545.stm |title = UK requests Lugovoi extradition| access-date = 2009-05-05|work=BBC News|date=2007-05-28}}</ref> it was subsequently determined that the <sup>210</sup>Po had probably been deliberately administered to him by two Russian ex-security agents, [[Andrey Lugovoy]] and [[Dmitry Kovtun]].<ref>{{cite web|url=https://www.litvinenkoinquiry.org/report|publisher=The Litvinenko Inquiry|title=Report|access-date=21 January 2016}}</ref><ref>{{cite news|last1=Addley|first1=Esther|last2=Harding|first2=Luke|title=Litvinenko 'probably murdered on personal orders of Putin'|url=https://www.theguardian.com/world/2016/jan/21/alexander-litvinenko-was-probably-murdered-on-personal-orders-of-putin|access-date=21 January 2016|work=The Guardian|date=21 January 2016}}</ref> As such, Litvinenko's death was the first (and, to date, only) confirmed instance in which polonium's extreme toxicity has been used with malicious intent.<ref>{{cite news |first=Steve |last=Boggan |title=Who else was poisoned by polonium? |work=[[The Guardian]] |date=5 June 2007 |url=https://www.theguardian.com/world/2007/jun/05/russia.science |access-date=28 August 2021}}</ref><ref name="PoAlJazeera">{{cite news |first=David |last=Poort |title=Polonium: a silent killer |work=Al Jazeera News |date=6 November 2013 |url=https://www.aljazeera.com/news/2013/11/6/polonium-a-silent-killer |access-date=28 August 2021}}</ref><ref>{{cite journal |last1=Froidevaux |first1=Pascal |last2=Bochud |first2=François |last3=Baechler |first3=Sébastien |last4=Castella |first4=Vincent |last5=Augsburger |first5=Marc |last6=Bailat |first6=Claude |last7=Michaud |first7=Katarzyna |last8=Straub |first8=Marietta |last9=Pecchia |first9=Marco |last10=Jenk |first10=Theo M. |last11=Uldin |first11=Tanya |last12=Mangin |first12=Patrice |date=February 2016 |title=²¹⁰Po poisoning as possible cause of death: forensic investigations and toxicological analysis of the remains of Yasser Arafat |journal=Forensic Science International |volume=259 |pages=1–9 |doi=10.1016/j.forsciint.2015.09.019 |pmid=26707208 |s2cid=207751390 |doi-access=free }}</ref>

In 2011, an allegation surfaced that the death of [[State of Palestine|Palestinian]] leader [[Yasser Arafat]], who died on 11 November 2004 of uncertain causes, also resulted from deliberate polonium poisoning,<ref>{{cite news|date=17 January 2011|title=الأخبار – ضابط فلسطيني: خصوم عرفات قتلوه عربي|publisher=[[Al Jazeera Media Network|Al Jazeera]]|url=http://www.aljazeera.net/news/pages/676ce5b7-f085-45d4-9c97-5c7a32864c06|url-status=dead|access-date=2021-06-05|archive-url=https://web.archive.org/web/20120704225411/http://www.aljazeera.net/news/pages/676ce5b7-f085-45d4-9c97-5c7a32864c06|archive-date=2012-07-04}}</ref><ref>{{cite episode |title=George Galloway and Alex Goldfarb on Litvinenko inquiry |url=https://www.youtube.com/watch?v=H0om8ii5XVs&t=113 | archive-url=https://ghostarchive.org/varchive/youtube/20211030/H0om8ii5XVs| archive-date=2021-10-30|series=[[Newsnight]] |network=[[BBC Television|BBC]] |date=21 January 2016 |time=1:53 |access-date=28 March 2018}}{{cbignore}}</ref> and in July 2012, concentrations of <sup>210</sup>Po many times more than normal were detected in Arafat's clothes and personal belongings by the Institut de Radiophysique in Lausanne, Switzerland.<ref>{{Cite journal | last1 = Froidevaux | first1 = P. | last2 = Baechler | first2 = S. B. | last3 = Bailat | first3 = C. J. | last4 = Castella | first4 = V. | last5 = Augsburger | first5 = M. | last6 = Michaud | first6 = K. | last7 = Mangin | first7 = P. | last8 = Bochud | first8 = F. O. O. | doi = 10.1016/S0140-6736(13)61834-6 | title = Improving forensic investigation for polonium poisoning | journal = The Lancet | volume = 382 | issue = 9900 | pages = 1308 | year = 2013 | pmid = 24120205| s2cid = 32134286}}</ref><ref name="BartReuters">Bart, Katharina (2012-07-03). [https://www.reuters.com/article/us-palestinians-arafat-idUSBRE8621CL20120703 Swiss institute finds polonium in Arafat's effects] {{Webarchive|url=https://web.archive.org/web/20151007125548/http://www.reuters.com/article/2012/07/03/us-palestinians-arafat-idUSBRE8621CL20120703 |date=2015-10-07 }}. Reuters.</ref> Even though Arafat's symptoms were acute gastroenteritis with diarrhoea and vomiting,<ref name="NBC News">{{cite news |last1=Paul Taylor |title=Palestinian leader Yasser Arafat was murdered with polonium: widow |url=https://www.nbcnews.com/news/world/palestinian-leader-yasser-arafat-was-murdered-polonium-widow-flna8C11542188 |work=NBC News |agency=Reuters |date=Nov 7, 2013}}</ref> the institute's spokesman said that despite the tests the symptoms described in Arafat's medical reports were not consistent with <sup>210</sup>Po poisoning, and conclusions could not be drawn.<ref name="BartReuters" /> In 2013 the team found levels of polonium in Arafat's ribs and pelvis 18 to 36 times the average,<ref name=AJ_Swiss_study>{{Cite web|last2=Silverstein|first1=David | last1=Poort| first2=Ken |title=Swiss study: Polonium found in Arafat's bones|url=https://www.aljazeera.com/news/2013/11/7/swiss-study-polonium-found-in-arafats-bones|access-date=12 February 2023 |publisher=www.aljazeera.com| date = 6 November 2013 |language=en}}</ref><ref name=Reuters_Arafat_poisoned>{{Cite news|title=Swiss Team: Arafat Poisoned to Death With Polonium |language=en|work=Haaretz|url=https://www.haaretz.com/2013-11-06/ty-article/swiss-team-arafat-poisoned-with-polonium/0000017f-e386-d7b2-a77f-e3876db50000 | date= 6 November 2013 |access-date=12 February 2023}}</ref> even though by this point in time the amount had diminished by a factor of 2 million.<ref name=LT24.05.14>{{in lang|fr}} Luis Lema, [https://www.letemps.ch/monde/yasser-arafat-valse-isotopes "Yasser Arafat, la valse des isotopes"], ''[[Le Temps]]'', Saturday 24 May 2014, p. 3.</ref> Forensic scientist Dave Barclay stated, "In my opinion, it is absolutely certain that the cause of his illness was polonium poisoning. ... What we have got is the smoking gun - the thing that caused his illness and was given to him with malice."<ref name="NBC News"/><ref name=AJ_Swiss_study/> Subsequently, French and Russian teams claimed that the elevated <sup>210</sup>Po levels were not the result of deliberate poisoning, and did not cause Arafat's death.<ref name="autogenerated1">Isachenkov, Vadim (2013-12-27) [https://web.archive.org/web/20131230234655/http://www.wtop.com/220/3531404/Russia-Arafats-death-not-caused-by-radiation Russia: Arafat's death not caused by radiation]. Associated Press.</ref><ref>{{cite news|date=3 December 2013|title=Arafat did not die of poisoning, French tests conclude|publisher=[[Reuters]]|url=https://www.reuters.com/article/us-palestinians-arafat-idUKBRE9B20DI20131203|access-date=1 September 2021}}</ref>

It has also been suspected that Russian businessman [[Roman Tsepov]] was killed with polonium. He had symptoms similar to Aleksander Litvinenko.<ref name=timesonline>{{Cite news|url=https://www.thetimes.com/comment/register/article/the-putin-bodyguard-riddle-687f9vcdmzf|title=The Putin bodyguard riddle|date=3 December 2006|newspaper=The Sunday Times}}</ref>

===Treatment===
It has been suggested that [[chelation therapy|chelation agents]], such as British anti-Lewisite ([[dimercaprol]]), can be used to decontaminate humans.<ref>{{cite web| url = https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm071944.pdf |title = Guidance for Industry. Internal Radioactive Contamination — Development of Decorporation Agents| access-date = 2009-07-07|work=US Food and Drug Administration}}</ref> In one experiment, rats were given a fatal dose of 1.45&nbsp;MBq/kg (8.7&nbsp;ng/kg) of <sup>210</sup>Po;
all untreated rats were dead after 44 days, but 90% of the rats treated with the chelation agent
HOEtTTC remained alive for five months.<ref>{{cite journal
|display-authors = 4
|author = Rencováa J.
|author2 = Svoboda V.
|author3 = Holuša R.
|author4 = Volf V.
|author5 = Jones M. M.
|author6 = Singh P. K.
|title = Reduction of subacute lethal radiotoxicity of polonium-210 in rats by chelating agents
|journal = International Journal of Radiation Biology
|volume = 72
|issue = 3
|pages = 341–8
|date = 1997
|doi = 10.1080/095530097143338
|pmid = 9298114
}}</ref>

===Detection in biological specimens===
Polonium-210 may be quantified in biological specimens by alpha particle spectrometry to confirm a diagnosis of poisoning in hospitalized patients or to provide evidence in a medicolegal death investigation. The baseline urinary excretion of polonium-210 in healthy persons due to routine exposure to environmental sources is normally in a range of 5–15 mBq/day. Levels in excess of 30 mBq/day are suggestive of excessive exposure to the radionuclide.<ref>Baselt, R. [http://www.biomedicalpublications.com/dt10.pdf ''Disposition of Toxic Drugs and Chemicals in Man''] {{Webarchive|url=https://web.archive.org/web/20130616021325/http://www.biomedicalpublications.com/dt10.pdf |date=2013-06-16 }}, 10th edition, Biomedical Publications, Seal Beach, CA.</ref>

===Occurrence in humans and the biosphere===
Polonium-210 is widespread in the [[biosphere]], including in human tissues, because of its position in the [[Uranium series|uranium-238 decay chain]]. Natural [[uranium-238]] in the [[Earth's crust]] decays through a series of solid radioactive intermediates including [[radium-226]] to the radioactive noble gas [[radon-222]], some of which, during its 3.8-day half-life, diffuses into the atmosphere. There it decays through several more steps to polonium-210, much of which, during its 138-day half-life, is washed back down to the Earth's surface, thus entering the biosphere, before finally decaying to stable [[lead-206]].<ref>{{cite journal|doi =10.1038/187211a0|pmid =13852349|title =Lead-210 and Polonium-210 in Grass|date =1960|last1 =Hill|first1 = C. R.|journal =Nature|volume =187|issue =4733|pages =211–212|bibcode = 1960Natur.187..211H|s2cid =4261294}}</ref><ref>{{cite journal|last = Hill|first = C. R.| date =1963|title = Natural occurrence of unsupported radium-F (Po-210) in tissue|journal = Health Physics|volume = 9|pages = 952–953|pmid = 14061910}}</ref><ref>{{cite journal|doi = 10.1007/BF00398136 |title = Polonium-210 and lead-210 in marine food chains|date = 1979|last1 = Heyraud|first1 = M.|last2 = Cherry|first2 = R. D.|journal = Marine Biology |volume = 52 |issue = 3 |pages = 227–236| bibcode=1979MarBi..52..227H |s2cid = 58921750}}</ref>

As early as the 1920s, French biologist [[Antoine Lacassagne]], using polonium provided by his colleague [[Marie Curie]], showed that the element has a specific pattern of uptake in rabbit tissues, with high concentrations, particularly in [[liver]], [[kidney]], and [[testes]].<ref>Lacassagne, A. & Lattes, J. (1924) ''Bulletin d'Histologie Appliquée à la Physiologie et à la Pathologie'', '''1''', 279.</ref> More recent evidence suggests that this behavior results from polonium substituting for its congener sulfur, also in group 16 of the periodic table, in sulfur-containing amino-acids or related molecules<ref>{{cite journal|jstor = 3577929|pages = 379–382|last1 = Vasken Aposhian|first1 = H.|last2 = Bruce|first2 = D. C.|title = Binding of Polonium-210 to Liver Metallothionein|volume = 126|issue = 3 |journal = Radiation Research |date = 1991 |doi = 10.2307/3577929 |pmid = 2034794|bibcode = 1991RadR..126..379A}}</ref> and that similar patterns of distribution occur in human tissues.<ref>{{cite journal |pmid = 5867584 |date = 1965 |last1 = Hill|first1 = C. R.|title = Polonium-210 in man|volume = 208|issue = 5009|pages = 423–8|journal = Nature |doi = 10.1038/208423a0|bibcode = 1965Natur.208..423H|s2cid = 4215661 }}</ref> Polonium is indeed an element naturally present in all humans, contributing appreciably to natural background dose, with wide geographical and cultural variations, and particularly high levels in arctic residents, for example.<ref>{{cite journal|doi = 10.1126/science.152.3726.1261 |title = Polonium-210 Content of Human Tissues in Relation to Dietary Habit|date = 1966|last1 = Hill|first1 = C. R.|journal = Science |volume = 152|issue = 3726|pages = 1261–2|pmid = 5949242 |bibcode = 1966Sci...152.1261H|s2cid = 33510717}}</ref>

===Tobacco===
[[Polonium-210]] in tobacco contributes to many of the cases of [[lung cancer]] worldwide. Most of this polonium is derived from [[lead-210]] deposited on tobacco leaves from the atmosphere; the lead-210 is a product of [[radon-222]] gas, much of which appears to originate from the decay of [[radium-226]] from fertilizers applied to the tobacco soils.<ref name="Muggli08" /><ref name="Martell1974">{{cite journal|last1=Martell|first1=E. A.|title=Radioactivity of tobacco trichomes and insoluble cigarette smoke particles|journal=Nature|date=1974|volume=249|issue=5454|pages=214–217|doi=10.1038/249215a0|pmid=4833238|bibcode=1974Natur.249..215M|s2cid=4281866}}</ref><ref name="Martell1975">{{cite journal|last1=Martell|first1=E. A.|title=Tobacco Radioactivity and Cancer in Smokers: Alpha interactions with chromosomes of cells surrounding insoluble radioactive smoke particles may cause cancer and contribute to early atherosclerosis development in cigarette smokers|journal=American Scientist|date=1975|volume=63|issue=4|pages=404–412|jstor=27845575|bibcode = 1975AmSci..63..404M |pmid=1137236}}</ref><ref>{{cite journal|journal=Journal of the Royal Society of Medicine|volume= 101|issue= 3|pages= 156–7|title= The big idea: polonium, radon and cigarettes|doi=10.1258/jrsm.2007.070021 |pmid= 18344474|pmc= 2270238|year= 2008|last1= Tidd|first1= M. J.}}</ref><ref>Birnbauer, William (2008-09-07) [http://www.theage.com.au/national/big-tobacco-covered-up-radiation-danger-20080906-4b54.html?page=-1 "Big Tobacco covered up radiation danger"]. ''The Age'', Melbourne, Australia</ref>

The presence of polonium in tobacco smoke has been known since the early 1960s.<ref>{{cite journal| author = Radford EP Jr| author2 = Hunt VR |title = Polonium 210: a volatile radioelement in cigarettes |journal = Science| date =1964| volume = 143| issue = 3603 | doi = 10.1126/science.143.3603.247| pmid=14078362| bibcode=1964Sci...143..247R| pages = 247–9| s2cid = 23455633 }}</ref><ref>{{cite journal| author = Kelley TF| title = Polonium 210 content of mainstream cigarette smoke| journal = Science| date =1965| volume =149| issue = 3683| pages = 537–538| doi = 10.1126/science.149.3683.537 | pmid = 14325152|bibcode = 1965Sci...149..537K| s2cid = 22567612}}</ref> Some of the world's biggest tobacco firms researched ways to remove the substance—to no avail—over a 40-year period. The results were never published.<ref name="Muggli08" />

===Food===
Polonium is found in the food chain, especially in seafood.<ref>{{cite journal |author=Ota, Tomoko |author2=Sanada, Tetsuya |author3=Kashiwara, Yoko |author4=Morimoto, Takao |author5=Sato, Kaneaki |display-authors=4 |name-list-style=amp |date=2009 |title=Evaluation for Committed Effective Dose Due to Dietary Foods by the Intake for Japanese Adults |url=http://ci.nii.ac.jp/naid/110007226760 |journal=Japanese Journal of Health Physics |volume=44 |issue=1 |pages=80–88 |doi=10.5453/jhps.44.80 |doi-access=free}}</ref><ref>{{cite journal |author=Smith-Briggs, JL |author2=Bradley, EJ |date=1984 |title=Measurement of natural radionuclides in U.K. diet |journal=Science of the Total Environment |volume=35 |issue=3 |pages=431–40 |bibcode=1984ScTEn..35..431S |doi=10.1016/0048-9697(84)90015-9 |pmid=6729447}}</ref>

===In Popular Culture===
Polonium poisoning has been used as a plot point on the American daytime television show [[General Hospital]] for many years.<ref>{{Cite web |last=Eades |first=Chris |date=2025-03-18 |title=Polonium Poisoning on GH — Everything You Need To Know! |url=https://www.soapsindepth.com/posts/general-hospital/polonium-poisoning-on-general-hospital-everything-you-need-to-know |access-date=2025-03-19 |website=Soaps In Depth |language=en-US}}</ref>