Polonium

²¹⁰Po is an alpha emitter that has a half-life of 138.4 days; it decays directly to its stable daughter isotope, ²⁰⁶Pb. A milligram (5 curies) of ²¹⁰Po emits about as many alpha particles per second as 5 grams of ²²⁶Ra, which means it is 5,000 times more radioactive than radium. A few curies (1 curie equals 37 gigabecquerels, 1 Ci = 37 GBq) of ²¹⁰Po emit a blue glow which is caused by ionisation of the surrounding air.

About one in 100,000 alpha emissions causes an excitation in the nucleus which then results in the emission of a gamma ray with a maximum energy of 803 keV.Greenwood, p. 250{{cite web|url=http://atom.kaeri.re.kr/cgi-bin/decay?Po-210%20A|title=210PO α decay|work=Nuclear Data Center, Korea Atomic Energy Research Institute|date= 2000|access-date=2009-05-05}}

File:alpha po lattice.jpg

Polonium is a radioactive element that exists in two metallic allotropes. The alpha form is the only known example of a simple cubic crystal structure in a single atom basis at STP (space group Pm{{overline|3}}m, no. 221). The unit cell has an edge length of 335.2 picometers; the beta form is rhombohedral.Greenwood, p. 753{{cite book |first1=Gary L. |last1=Miessler |first2=Donald A. |last2=Tarr |title=Inorganic Chemistry |edition=3rd |page=[https://archive.org/details/inorganicchemist03edmies/page/285 285] |isbn=978-0-13-120198-9 |date=2004 |publisher=Pearson Prentice Hall |location=Upper Saddle River, N.J. |url=https://archive.org/details/inorganicchemist03edmies/page/285 }}{{cite web| url = http://cst-www.nrl.navy.mil/lattice/struk/a_i.html| archive-url = https://web.archive.org/web/20010204004200/http://cst-www.nrl.navy.mil/lattice/struk/a_i.html| archive-date = 2001-02-04|date= 2000-11-20|work=Naval Research Laboratory |title = The beta Po (A_i) Structure| access-date = 2009-05-05}} The structure of polonium has been characterized by X-ray diffraction{{cite journal |last=Desando |first=R. J. |author2=Lange, R. C. |date=1966 |title=The structures of polonium and its compounds—I α and β polonium metal |journal=Journal of Inorganic and Nuclear Chemistry |volume=28 |issue=9 |pages=1837–1846 |doi=10.1016/0022-1902(66)80270-1}}{{cite journal |last=Beamer |first=W. H. |author2=Maxwell, C. R. |date=1946 |title=The Crystal Structure of Polonium |journal=Journal of Chemical Physics |volume=14 |issue=9 |page=569 |doi=10.1063/1.1724201|hdl=2027/mdp.39015086430371 |hdl-access=free }} and electron diffraction.{{cite journal |last1=Rollier |first1=M. A. |last2=Hendricks |first2=S. B.|last3= Maxwell|first3=L. R. |date=1936 |title=The Crystal Structure of Polonium by Electron Diffraction |journal=Journal of Chemical Physics |volume=4 |issue=10 |page=648 |doi=10.1063/1.1749762 |bibcode = 1936JChPh...4..648R|doi-access=free }}

²¹⁰Po has the ability to become airborne with ease: if a sample is heated in air to {{convert|55|C|F}}, 50% of it is vaporized in 45 hours to form diatomic Po₂ molecules, even though the melting point of polonium is {{convert|254|C|F}} and its boiling point is {{convert|962|C|F}}.{{cite journal| first1 = Bogdan |last1=Wąs| first2 = Ryszard |last2=Misiak| first3 = Mirosław |last3=Bartyzel| first4 = Barbara |last4=Petelenz | title = Thermochromatographic separation of ^206,208Po from a bismuth target bombarded with protons | journal =Nukleonika | date =2006| volume =51 | issue = Suppl. 2 | pages = s3–s5 | url =http://www.ichtj.waw.pl/ichtj/nukleon/back/full/vol51_2006/v51s2p03f.pdf}}{{RubberBible86th}}

More than one hypothesis exists for how polonium does this; one suggestion is that small clusters of polonium atoms are spalled off by the alpha decay.{{cite conference|title=Pseudo-evaporation of high specific activity alpha-emitting materials|author1= Condit, Ralph H.|author2=Gray, Leonard W.| author3=Mitchell, Mark A.|url=https://www.osti.gov/biblio/1162255| conference=EFCOG 2014 Safety Analysis Workshop|year=2014|publisher=Lawrence Livermore National Laboratory|osti= 1162255|conference-url=https://www.osti.gov/biblio/1169821}}

The chemistry of polonium is similar to that of tellurium, although it also shows some similarities to its neighbor bismuth due to its metallic character. Polonium dissolves readily in dilute acids but is only slightly soluble in alkalis. Polonium solutions are first colored in pink by the Po²⁺ ions, but then rapidly become yellow because alpha radiation from polonium ionizes the solvent and converts Po²⁺ into Po⁴⁺. As polonium also emits alpha-particles after disintegration so this process is accompanied by bubbling and emission of heat and light by glassware due to the absorbed alpha particles; as a result, polonium solutions are volatile and will evaporate within days unless sealed.Bagnall, p. 206 At pH about 1, polonium ions are readily hydrolyzed and complexed by acids such as oxalic acid, citric acid, and tartaric acid.{{Ullmann | first1=Cornelius |last1=Keller |first2=Walter |last2=Wolf |first3=Jashovam |last3=Shani | title = Radionuclides, 2. Radioactive Elements and Artificial Radionuclides | doi = 10.1002/14356007.o22_o15}}

Polonium has no common compounds, and almost all of its compounds are synthetically created; more than 50 of those are known.Bagnall, p. 199 The most stable class of polonium compounds are polonides, which are prepared by direct reaction of two elements. Na₂Po has the antifluorite structure, the polonides of Ca, Ba, Hg, Pb and lanthanides form a NaCl lattice, BePo and CdPo have the wurtzite and MgPo the nickel arsenide structure. Most polonides decompose upon heating to about 600 °C, except for HgPo that decomposes at ~300 °C and the lanthanide polonides, which do not decompose but melt at temperatures above 1000 °C. For example, the polonide of praseodymium (PrPo) melts at 1250 °C, and that of thulium (TmPo) melts at 2200 °C.Greenwood, p. 766 PbPo is one of the very few naturally occurring polonium compounds, as polonium alpha decays to form lead.{{cite journal |last1=Weigel |first1=F. |date=1959 |title=Chemie des Poloniums |journal=Angewandte Chemie |volume=71 |pages=289–316 |doi=10.1002/ange.19590710902 |issue=9|bibcode=1959AngCh..71..289W }}

Polonium hydride ({{chem|Po||H|2}}) is a volatile liquid at room temperature prone to dissociation; it is thermally unstable. Water is the only other known hydrogen chalcogenide which is a liquid at room temperature; however, this is due to hydrogen bonding. The three oxides, PoO, PoO₂ and PoO₃, are the products of oxidation of polonium.{{cite book| author = Holleman, A. F.| author2 = Wiberg, E. |title = Inorganic Chemistry| publisher = Academic Press| location = San Diego| date = 2001| isbn = 978-0-12-352651-9}}

Halides of the structure PoX₂, PoX₄ and PoF₆ are known. They are soluble in the corresponding hydrogen halides, i.e., PoCl_X in HCl, PoBr_X in HBr and PoI₄ in HI. Polonium dihalides are formed by direct reaction of the elements or by reduction of PoCl₄ with SO₂ and with PoBr₄ with H₂S at room temperature. Tetrahalides can be obtained by reacting polonium dioxide with HCl, HBr or HI.Greenwood, pp. 765, 771, 775

Other polonium compounds include the polonite, potassium polonite; various polonate solutions; and the acetate, bromate, carbonate, citrate, chromate, cyanide, formate, (II) or (IV) hydroxide, nitrate, selenate, selenite, monosulfide, sulfate, disulfate or sulfite salts.Figgins, P. E. (1961) [http://www.osti.gov/bridge/purl.cover.jsp?purl=/4034029-SolPsF/ The Radiochemistry of Polonium], National Academy of Sciences, US Atomic Energy Commission, pp. 13–14 [https://books.google.com/books?id=N0MrAAAAYAAJ Google Books]Bagnall, pp. 212–226

A limited organopolonium chemistry is known, mostly restricted to dialkyl and diaryl polonides (R₂Po), triarylpolonium halides (Ar₃PoX), and diarylpolonium dihalides (Ar₂PoX₂).{{cite book |last=Zingaro |first=Ralph A. |chapter=Polonium: Organometallic Chemistry |date=2011 |title=Encyclopedia of Inorganic and Bioinorganic Chemistry |publisher=John Wiley & Sons |pages=1–3 |doi=10.1002/9781119951438.eibc0182|isbn=9781119951438 }}{{cite journal |last1=Murin |first1=A. N. |last2=Nefedov |first2=V. D. |first3=V. M. |last3=Zaitsev |first4=S. A. |last4=Grachev |date=1960 |title=Production of organopolonium compounds by using chemical alterations taking place during the β-decay of RaE |url=http://www.mathnet.ru/links/d4bd811f2ded6e2b1d67f43a93e2910e/dan23789.pdf |journal=Dokl. Akad. Nauk SSSR |volume=133 |issue=1 |pages=123–125 |access-date=12 April 2020 |language=ru}} Polonium also forms soluble compounds with some ligands, such as 2,3-butanediol and thiourea.

{{col-begin}}

{{col-break}}

Oxides

• PoO
• PoO₂
• PoO₃

{{col-break}}

Hydrides

• PoH₂

{{col-break}}

Halides

• PoX₂ (except PoF₂)
• PoX₄
• PoF₆
• PoBr₂Cl₂ (salmon pink)

{{col-end}}

{{Main|Isotopes of polonium}}

Polonium has 42 known isotopes, all of which are radioactive. They have atomic masses that range from 186 to 227 u. ²¹⁰Po (half-life 138.376 days) is the most widely available and is manufactured via neutron capture by natural bismuth. It also naturally occurs as a trace in uranium ores, as it is the penultimate member of the decay chain of ²³⁸U. The longer-lived ²⁰⁹Po (half-life 124 years, longest-lived of all polonium isotopes){{NUBASE2020|ref}} and ²⁰⁸Po (half-life 2.9 years) can be manufactured through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron.{{cite book|last=Emsley|first=John|title=Nature's Building Blocks: An A-Z Guide to the Elements|edition=New|date=2011|publisher=Oxford University Press|location=New York, NY|isbn=978-0-19-960563-7|page=415}}

Tentatively called "radium F", polonium was discovered by Marie and Pierre Curie in July 1898,{{cite journal|author1=Curie, P. |author2=Curie, M. |title=Sur une substance nouvelle radio-active, contenue dans la pechblende |trans-title=On a new radioactive substance contained in pitchblende |language=fr |journal=Comptes Rendus |volume=127 |pages=175–178 |date=1898 |url=http://www.academie-sciences.fr/activite/archive/dossiers/Curie/Curie_pdf/CR1898_p175_178.pdf |url-status=unfit |archive-url=https://web.archive.org/web/20130723022419/http://www.academie-sciences.fr/activite/archive/dossiers/Curie/Curie_pdf/CR1898_p175_178.pdf |archive-date=23 July 2013 }} [http://web.lemoyne.edu/~giunta/curiespo.html English translation.]{{Cite web|url=http://elements.vanderkrogt.net/element.php?sym=po|title=84. Polonium – Elementymology & Elements Multidict|last=Krogt|first=Peter van der|website=elements.vanderkrogt.net|access-date=2017-04-26}} and was named after Marie Curie's native land of Poland ({{langx|la|Polonia}}).{{cite journal

| title = Borders of the Nuclear World – 100 Years After Discovery of Polonium

| last = Pfützner | first =M.

| journal = Acta Physica Polonica B

| volume = 30

| issue = 5 | date = 1999

| page= 1197

| bibcode =1999AcPPB..30.1197P}}{{cite journal

| title = The centennial of the 1903 Nobel Prize for physics

| last = Adloff | first = J. P.

| journal = Radiochimica Acta

| volume = 91

| issue = 12–2003

| pages=681–688

| date=2003

| doi = 10.1524/ract.91.12.681.23428| s2cid = 120150862 }} Poland at the time was under Russian, German, and Austro-Hungarian partition, and did not exist as an independent country. It was Curie's hope that naming the element after her native land would publicize its lack of independence. Polonium may be the first element named to highlight a political controversy.{{cite journal

| title = Chemical and Polish aspects of polonium and radium discovery

| last = Kabzinska | first =K.

| journal = Przemysł Chemiczny

| volume = 77

| date = 1998

| pages = 104–107

| issue = 3}}

This element was the first one discovered by the Curies while they were investigating the cause of pitchblende radioactivity. Pitchblende, after removal of the radioactive elements uranium and thorium, was more radioactive than the uranium and thorium combined. This spurred the Curies to search for additional radioactive elements. They first separated out polonium from pitchblende in July 1898, and five months later, also isolated radium.{{cite journal |author1=Curie, P. |author2=Curie, M. |author3=Bémont, G. |title=Sur une nouvelle substance fortement radio-active contenue dans la pechblende |trans-title=On a new, strongly radioactive substance contained in pitchblende |language=fr |journal=Comptes Rendus |volume=127 |pages=1215–1217 |date=1898 |url=http://www.academie-sciences.fr/activite/archive/dossiers/Curie/Curie_pdf/CR1898_p1215_1217.pdf |archive-url=https://web.archive.org/web/20130722232602/http://www.academie-sciences.fr/activite/archive/dossiers/Curie/Curie_pdf/CR1898_p1215_1217.pdf |archive-date=22 July 2013 }} [http://www.aip.org/history/curie/discover.htm English translation] {{Webarchive|url=https://web.archive.org/web/20090806083923/http://www.aip.org/history/curie/discover.htm |date=6 August 2009 }} German scientist Willy Marckwald successfully isolated 3 milligrams of polonium in 1902, though at the time he believed it was a new element, which he dubbed "radio-tellurium", and it was not until 1905 that it was demonstrated to be the same as polonium.{{cite journal | title = Polonium and Radio-Tellurium | journal = Nature | volume = 73 | issue = 549 | pages = 549 |date = 1906 | doi = 10.1038/073549b0| bibcode = 1906Natur..73R.549. | doi-access = free }}{{cite book |last = Neufeldt |first = Sieghard | title = Chronologie Chemie: Entdecker und Entdeckungen | publisher = John Wiley & Sons | year = 2012 | isbn = 9783527662845 | url = {{Google books|0lFQjLAlgC0C|plainurl=y|page=115}} }}

In the United States, polonium was produced as part of the Manhattan Project's Dayton Project during World War II. Polonium and beryllium were the key ingredients of the 'Urchin' initiator at the center of the bomb's spherical pit.[http://nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html Nuclear Weapons FAQ, Section 4.1, Version 2.04: 20 February 1999]. Nuclearweaponarchive.org. Retrieved on 2013-04-28. 'Urchin' initiated the nuclear chain reaction at the moment of prompt-criticality to ensure that the weapon did not fizzle. 'Urchin' was used in early U.S. weapons; subsequent U.S. weapons utilized a pulse neutron generator for the same purpose.

Much of the basic physics of polonium was classified until after the war. The fact that a polonium-beryllium (Po-Be) initiator was used in the gun-type nuclear weapons was classified until the 1960s.{{cite web | author=US Department of Energy Office of Declassification | title=Restricted data declassification decisions, 1946 to the present (RDD-7) | website=FAS Project on Government Secrecy (1991-2021), fas.org | date=2001-01-01 | url=https://sgp.fas.org/othergov/doe/rdd-7.html#I16 | access-date=2024-01-30}}

The Atomic Energy Commission and the Manhattan Project funded human experiments using polonium on five people at the University of Rochester between 1943 and 1947. The people were administered between {{convert|9|and|22|μCi|kBq|lk=on}} of polonium to study its excretion.[http://contentdm.library.unr.edu/cdm4/item_viewer.php?CISOROOT=/conghear&CISOPTR=102&CISOBOX=1&REC=1#metajump American nuclear guinea pigs: three decades of radiation experiments on U.S. citizens] {{Webarchive|url=https://web.archive.org/web/20130730200210/http://contentdm.library.unr.edu/cdm4/item_viewer.php?CISOROOT=%2Fconghear&CISOPTR=102&CISOBOX=1&REC=1#metajump |date=2013-07-30 }}. United States. Congress. House. of the Committee on Energy and Commerce. Subcommittee on Energy Conservation and Power, published by U.S. Government Printing Office, 1986, Identifier Y 4.En 2/3:99-NN, Electronic Publication Date 2010, at the University of Nevada, Reno, unr.edu"Studies of polonium metabolism in human subjects", Chapter 3 in Biological Studies with Polonium, Radium, and Plutonium, National, Nuclear Energy Series, Volume VI-3, McGraw-Hill, New York, 1950, cited in "American Nuclear Guinea Pigs ...", 1986 House Energy and Commerce committee reportMoss, William and Eckhardt, Roger (1995) [https://fas.org/sgp/othergov/doe/lanl/pubs/00326640.pdf "The Human Plutonium Injection Experiments"], Los Alamos Science, Number 23.

Polonium is a very rare element in nature because of the short half-lives of all its isotopes. Nine isotopes, from 210 to 218 inclusive, occur in traces as decay products: ²¹⁰Po, ²¹⁴Po, and ²¹⁸Po occur in the decay chain of ²³⁸U; ²¹¹Po and ²¹⁵Po occur in the decay chain of ²³⁵U; ²¹²Po and ²¹⁶Po occur in the decay chain of ²³²Th; and ²¹³Po and ²¹⁷Po occur in the decay chain of ²³⁷Np. (No primordial ²³⁷Np survives, but traces of it are continuously regenerated through (n,2n) knockout reactions in natural ²³⁸U.){{cite journal |last1=Peppard |first1=D. F. |last2=Mason |first2=G. W. |last3=Gray |first3=P. R. |last4=Mech |first4=J. F. |title=Occurrence of the (4n + 1) series in nature |journal=Journal of the American Chemical Society |date=1952 |volume=74 |issue=23 |pages=6081–6084 |doi=10.1021/ja01143a074 |bibcode=1952JAChS..74.6081P |url=https://digital.library.unt.edu/ark:/67531/metadc172698/m2/1/high_res_d/metadc172698.pdf }} Of these, ²¹⁰Po is the only isotope with a half-life longer than 3 minutes.{{Cite journal| last1=Carvalho|first1=F.|last2=Fernandes|first2=S.|last3=Fesenko|first3=S. |last4=Holm|first4=E.|last5=Howard|first5=B.|last6=Martin|first6=P.|last7=Phaneuf|first7=P. |last8=Porcelli|first8=D.|last9=Pröhl|first9=G.|last10=Twining|first10=J.|title=The Environmental Behaviour of Polonium|journal=Technical Reports Series – International Atomic Energy Agency|series=Technical reports series|volume=484|publisher=International Atomic Energy Agency|location=Vienna|date=2017|page=1|isbn=978-92-0-112116-5}}

Polonium can be found in uranium ores at about 0.1 mg per metric ton (1 part in 10¹⁰),Greenwood, p. 746Bagnall, p. 198 which is approximately 0.2% of the abundance of radium. The amounts in the Earth's crust are not harmful. Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers.{{cite journal| last = Kilthau | first = Gustave F. |title = Cancer risk in relation to radioactivity in tobacco |journal = Radiologic Technology |volume = 67 |pages = 217–222| pmid = 8850254| date = 1996| issue = 3}}{{cite web|url=http://kidslink.bo.cnr.it/besta/fumo/epolonio.html |title=Alpha Radioactivity (210 Polonium) and Tobacco Smoke |access-date=2009-05-05 |url-status=dead |archive-url=https://web.archive.org/web/20130609055245/http://kidslink.bo.cnr.it/besta/fumo/epolonio.html |archive-date=June 9, 2013 }}{{cite journal |title = Waking a Sleeping Giant: The Tobacco Industry's Response to the Polonium-210 Issue |last1 = Monique | first1 = E. Muggli |journal = American Journal of Public Health |volume = 98 |issue = 9| date = 2008 |pmid = 18633078|pmc = 2509609 |doi = 10.2105/AJPH.2007.130963 |pages = 1643–50 |last2 = Ebbert |first2 = Jon O. |last3 = Robertson |first3 = Channing |last4 = Hurt |first4 = Richard D.}}

Because it is present in small concentrations, isolation of polonium from natural sources is a tedious process. The largest batch of the element ever extracted, performed in the first half of the 20th century, contained only {{convert|40|Ci|TBq|abbr=on}} (9 mg) of polonium-210 and was obtained by processing 37 tonnes of residues from radium production.{{cite journal|author=Adloff, J. P.|author2=MacCordick, H. J.|name-list-style=amp|title=The Dawn of Radiochemistry|journal=Radiochimica Acta|volume=70/71|pages=13–22|date=1995|issue=Supplement |url=http://www.nucleonica.com/wiki/Articles/Article03/Article3.htm|doi=10.1524/ract.1995.7071.special-issue.13|s2cid=99790464}}, reprinted in {{cite book|url = https://books.google.com/books?id=whGiCQywLi8C&pg=PA17|title = One hundred years after the discovery of radioactivity|isbn = 978-3-486-64252-0|last1 = Adloff|first1 = J. P.|date = 1996|page = 17|publisher = Walter de Gruyter GmbH}}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }} Polonium is now usually obtained by irradiating bismuth with high-energy neutrons or protons.Greenwood, p. 249

In 1934, an experiment showed that when natural ²⁰⁹Bi is bombarded with neutrons, ²¹⁰Bi is created, which then decays to ²¹⁰Po via beta-minus decay. By irradiating certain bismuth salts containing light element nuclei such as beryllium, a cascading (α,n) reaction can also be induced to produce ²¹⁰Po in large quantities.{{cite journal |title =Neutronic Chain Reactions for Polonium-210 Production |first =Solomon |last = Lim |journal = SSRN |date = 2023 |doi = 10.2139/ssrn.4469519|s2cid =264176122 |url =https://hal.science/hal-04196973/file/Report%20210.pdf }} The final purification is done pyrochemically followed by liquid-liquid extraction techniques.{{cite journal |title =Pyrochemical Extraction of Polonium from Irradiated Bismuth Metal |first =Wallace W. |last = Schulz |author2 = Schiefelbein, Gary F. |author3 = Bruns, Lester E. |journal = Ind. Eng. Chem. Process Des. Dev. |date = 1969 |volume = 8 |issue = 4 |pages= 508–515| doi = 10.1021/i260032a013}} Polonium may now be made in milligram amounts in this procedure which uses high neutron fluxes found in nuclear reactors. Only about 100 grams are produced each year, practically all of it in Russia, making polonium exceedingly rare.{{cite web |title = Q&A: Polonium-210 |url =http://www.rsc.org/chemistryworld/News/2006/November/27110601.asp |publisher = RSC Chemistry World |date = 2006-11-27 |access-date =2009-01-12}}{{cite web |date=2007-01-11 |title=Most Polonium Made Near the Volga River |url=https://www.themoscowtimes.com/archive/most-polonium-made-near-the-volga-river |publisher=The Moscow Times – News}}

This process can cause problems in lead-bismuth based liquid metal cooled nuclear reactors such as those used in the Soviet Navy's K-27. Measures must be taken in these reactors to deal with the unwanted possibility of ²¹⁰Po being released from the coolant.{{cite journal|title=Long-lived radionuclides of sodium, lead-bismuth, and lead coolants in fast-neutron reactors|journal=Atomic Energy|volume =87|issue=3 |year=1999|pages=658–662|doi=10.1007/BF02673579|last1=Usanov|first1=V. I.|last2=Pankratov|first2=D. V.|last3=Popov|first3=É. P.|last4=Markelov|first4=P. I.|last5=Ryabaya|first5=L. D.|last6=Zabrodskaya|first6=S. V.|s2cid=94738113}}{{cite journal|author=Naumov, V. V. |date=November 2006|url=http://www.antiatom.ru/2006_12-11.php|script-title=ru:За какими корабельными реакторами будущее?|language=ru|journal= Атомная стратегия |volume= 26}}

The longer-lived isotopes of polonium, ²⁰⁸Po and ²⁰⁹Po, can be formed by proton or deuteron bombardment of bismuth using a cyclotron. Other more neutron-deficient and more unstable isotopes can be formed by the irradiation of platinum with carbon nuclei.{{cite journal| author = Atterling, H.| author2 = Forsling, W. |title = Light Polonium Isotopes from Carbon Ion Bombardments of Platinum |journal = Arkiv för Fysik |volume = 15| issue = 1 |pages = 81–88 |date = 1959 |osti =4238755}}

Polonium-based sources of alpha particles were produced in the former Soviet Union. Such sources were applied for measuring the thickness of industrial coatings via attenuation of alpha radiation.Bagnall, p. 225

Because of intense alpha radiation, a one-gram sample of ²¹⁰Po will spontaneously heat up to above {{convert|500|C|F}} generating about 140 watts of power. Therefore, ²¹⁰Po is used as an atomic heat source to power radioisotope thermoelectric generators via thermoelectric materials.{{cite web| url =http://www.ead.anl.gov/pub/doc/polonium.pdf | archive-url =https://web.archive.org/web/20070703021010/http://www.ead.anl.gov/pub/doc/polonium.pdf | archive-date =2007-07-03 |title = Polonium |publisher = Argonne National Laboratory| access-date = 2009-05-05}}Greenwood, p. 251{{cite book |url=https://books.google.com/books?id=07TEK_w3A4AC&pg=PA183 |page=183 |last=Hanslmeier |first= Arnold |title= The sun and space weather |publisher=Springer |date=2002 |isbn=978-1-4020-0684-5}} For example, ²¹⁰Po heat sources were used in the Lunokhod 1 (1970) and Lunokhod 2 (1973) Moon rovers to keep their internal components warm during the lunar nights, as well as the Kosmos 84 and 90 satellites (1965).{{cite web |url=http://npc.sarov.ru/issues/sarovbook/section3p11.html |archive-url=https://web.archive.org/web/20070501055529/http://npc.sarov.ru/issues/sarovbook/section3p11.html |archive-date=May 1, 2007 |title=Радиоизотопные источники тепла |url-status=dead |access-date=June 1, 2016}} (in Russian). npc.sarov.ru{{cite book | first = Andrew | last = Wilson | title = Solar System Log | location = London | publisher = Jane's Publishing Company Ltd | date = 1987 | page = [https://archive.org/details/solarsystemlog00andr/page/64 64] | isbn = 978-0-7106-0444-6 | url = https://archive.org/details/solarsystemlog00andr/page/64 }}

The alpha particles emitted by polonium can be converted to neutrons using beryllium oxide, at a rate of 93 neutrons per million alpha particles. Po-BeO mixtures are used as passive neutron sources with a gamma-ray-to-neutron production ratio of 1.13 ± 0.05, lower than for nuclear fission-based neutron sources.{{cite arXiv |last=Ritter |first=Sebastian |eprint=2111.02774 |title=Comparative Study of Gamma to Neutron Ratios of various (alpha, neutron) Neutron Sources |class=nucl-ex |date= 2021}} Examples of Po-BeO mixtures or alloys used as neutron sources are a neutron trigger or initiator for nuclear weapons{{cite book| last = Emsley| first =John |title = Nature's Building Blocks| publisher = Oxford University Press| location = New York| date = 2001| pages = 330–332| isbn = 978-0-19-850341-5}}{{cite book| author = Rhodes, Richard| title = Dark Sun: The Making of the Hydrogen Bomb| publisher = Walker & Company| location = New York| date = 2002| pages = [https://archive.org/details/darksunmakingofh00rhod/page/187 187–188]| isbn = 978-0-684-80400-2| url = https://archive.org/details/darksunmakingofh00rhod/page/187}} and for inspections of oil wells. About 1500 sources of this type, with an individual activity of {{convert|1850|Ci|TBq|abbr=on}}, had been used annually in the Soviet Union.[http://www.stringer.ru/publication.mhtml?Part=50&PubID=6767 Красивая версия "самоубийства" Литвиненко вследствие криворукости] (in Russian). stringer.ru (2006-11-26).

Polonium was also part of brushes or more complex tools that eliminate static charges in photographic plates, textile mills, paper rolls, sheet plastics, and on substrates (such as automotive) prior to the application of coatings.{{cite journal |last1=Boice |first1=John D. |last2=Cohen |first2=Sarah S. |last3=Mumma |first3=Michael T. |last4=Ellis |first4=Elizabeth Dupree |last5=Cragle |first5=Donna L. |last6=Eckerman |first6=Keith F. |last7=Wallace |first7=Philip W. |last8=Chadda |first8=Bandana |last9=Sonderman |first9=Jennifer S. |last10=Wiggs |first10=Laurie D. |last11=Richter |first11=Bonnie S. |last12=Leggett |first12=Richard W. |title=Mortality Among Mound Workers Exposed to Polonium-210 and Other Sources of Radiation, 1944–1979 |journal=Radiation Research |volume=181 |issue=2 |date=2014 |pages=208–28 |doi=10.1667/RR13395.1 |pmid=24527690 |display-authors=2|bibcode=2014RadR..181..208B |osti=1286690 |s2cid=7350371 }} Alpha particles emitted by polonium ionize air molecules that neutralize charges on the nearby surfaces.{{cite web|url=http://www.thermo.com/eThermo/CMA/PDFs/Articles/articlesFile_16929.pdf |title=Static Control for Electronic Balance Systems |access-date=2009-05-05 |url-status=dead |archive-url=https://web.archive.org/web/20131110213624/http://www.thermo.com/eThermo/CMA/PDFs/Articles/articlesFile_16929.pdf |archive-date=November 10, 2013 }}{{cite news| url =http://news.bbc.co.uk/1/hi/england/1868414.stm |title =BBC News : College breaches radioactive regulations| access-date = 2009-05-05|date=2002-03-12}} Some anti-static brushes contain up to {{convert|500|uCi|MBq|sigfig=1}} of ²¹⁰Po as a source of charged particles for neutralizing static electricity.{{cite web |url = http://www.amstat.com/solutions/staticmaster.html |title = Staticmaster Ionizing Brushes |publisher = AMSTAT Industries |access-date = 2009-05-05 |archive-date = 2009-09-26 |archive-url = https://web.archive.org/web/20090926032436/http://www.amstat.com/solutions/staticmaster.html |url-status = dead }} In the US, devices with no more than {{convert|500|μCi|MBq|abbr=on}} of (sealed) ²¹⁰Po per unit can be bought in any amount under a "general license",{{cite web| url = https://www.nrc.gov/reading-rm/doc-collections/cfr/part031/full-text.html| title = General domestic licenses for byproduct material| access-date = 2009-05-05}} which means that a buyer need not be registered by any authorities. Polonium needs to be replaced in these devices nearly every year because of its short half-life; it is also highly radioactive and therefore has been mostly replaced by less dangerous beta particle sources.

Tiny amounts of ²¹⁰Po are sometimes used in the laboratory and for teaching purposes—typically of the order of {{convert|4|-|40|kBq|μCi|abbr=on}}, in the form of sealed sources, with the polonium deposited on a substrate or in a resin or polymer matrix—are often exempt from licensing by the NRC and similar authorities as they are not considered hazardous. Small amounts of ²¹⁰Po are manufactured for sale to the public in the United States as "needle sources" for laboratory experimentation, and they are retailed by scientific supply companies. The polonium is a layer of plating which in turn is plated with a material such as gold, which allows the alpha radiation (used in experiments such as cloud chambers) to pass while preventing the polonium from being released and presenting a toxic hazard.{{citation needed|date=February 2023}}

Polonium spark plugs were marketed by Firestone from 1940 to 1953. While the amount of radiation from the plugs was minuscule and not a threat to the consumer, the benefits of such plugs quickly diminished after approximately a month because of polonium's short half-life and because buildup on the conductors would block the radiation that improved engine performance. (The premise behind the polonium spark plug, as well as Alfred Matthew Hubbard's prototype radium plug that preceded it, was that the radiation would improve ionization of the fuel in the cylinder and thus allow the motor to fire more quickly and efficiently.){{cite web|url=https://www.orau.org/health-physics-museum/collection/consumer/miscellaneous/spark-plugs.html|title=Radioactive spark plugs|publisher=Oak Ridge Associated Universities|date=January 20, 1999|access-date=October 7, 2021}}{{cite web|url=http://www.utoledo.edu/nsm/ic/elements/polonium.html|first=Cassandra|last=Pittman|title=Polonium|work=The Instrumentation Center|publisher=University of Toledo|date=February 3, 2017|access-date=August 23, 2018}}

Polonium can be hazardous and has no biological role. By mass, polonium-210 is around 250,000 times more toxic than hydrogen cyanide (the {{LD50}} for ²¹⁰Po is less than 1 microgram for an average adult (see below) compared with about 250 milligrams for hydrogen cyanide{{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}}). The main hazard is its intense radioactivity (as an alpha emitter), which makes it difficult to handle safely. Even in microgram amounts, handling ²¹⁰Po 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 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.Bagnall, pp. 202–6

Polonium does not have toxic chemical properties.{{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}}

It has been reported that some microbes can methylate polonium by the action of methylcobalamin.{{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}}

{{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}} This is similar to the way in which 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.{{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 ²¹⁰Po in rats: volatile ²¹⁰Po in excreta |journal=Radiation Protection Dosimetry |volume=140 |issue=2 |pages=158–162 |doi=10.1093/rpd/ncq047 |pmid=20159915}}

The median lethal dose (LD₅₀) for acute radiation exposure is about 4.5 Sv.{{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}} The committed effective dose equivalent ²¹⁰Po is 0.51 μSv/Bq if ingested, and 2.5 μSv/Bq if inhaled.{{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}} A fatal 4.5 Sv dose can be caused by ingesting {{convert|8.8|MBq|μCi|abbr=on}}, about 50 nanograms (ng), or inhaling {{convert|1.8|MBq|μCi|abbr=on}}, about 10 ng. One gram of ²¹⁰Po could thus in theory poison 20 million people, of whom 10 million would die. The actual toxicity of ²¹⁰Po 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 to 50 days{{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}}) is somewhat less damaging than an instantaneous dose. It has been estimated that a median lethal dose of ²¹⁰Po is {{convert|15|MBq|mCi}}, or 0.089 micrograms (μg), still an extremely small amount.{{cite web| url =http://nuclearweaponarchive.org/News/PoloniumPoison.html |title =Polonium Poisoning|author=Carey Sublette|date=2006-12-14| access-date = 2009-05-05}}{{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 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 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 }} For comparison, one grain of table salt is about 0.06 mg = 60 μg.{{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}}

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. The general population is exposed to small amounts of polonium as a radon daughter in indoor air; the isotopes ²¹⁴Po and ²¹⁸Po are thought to cause the majority{{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}} of the estimated 15,000–22,000 lung cancer deaths in the US every year that have been attributed to indoor radon.{{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}} Tobacco smoking causes additional exposure to polonium.{{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}}

The maximum allowable body burden for ingested ²¹⁰Po is only {{convert|1.1|kBq|nCi|abbr=on}}, which is equivalent to a particle massing only 6.8 picograms.{{Cite journal |last1=Boryło |first1=Alicja |last2=Skwarzec |first2=Bogdan |last3=Wieczorek |first3=Jarosław |date=2022-02-10 |title=Sources of polonium ²¹⁰Po and radio-lead ²¹⁰Pb 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}} The maximum permissible workplace concentration of airborne ²¹⁰Po is about 10 Bq/m³ ({{val|3|e=-10}} μCi/cm³).{{cite web |url = https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Polonium-210.html |title = Nuclear Regulatory Commission limits for ²¹⁰Po| date = 2008-12-12 |access-date = 2009-01-12 |publisher = U.S. NRC}} The target organs for polonium in humans are the spleen and liver.{{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 }} As the spleen (150 g) and the liver (1.3 to 3 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 T₂O).{{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}}{{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}}

²¹⁰Po is widely used in industry, and readily available with little regulation or restriction.{{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| url=https://www.researchgate.net/publication/314571422}} 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 ... There is talk that it might tighten the polonium reporting requirement by a factor of 10, to {{convert|1.6|Ci}}."{{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}} 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 boxes, 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 while minimizing its sorption onto glass. They do not provide sufficient protection against the contamination from polonium (diffusion of ²¹⁰Po 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 ²¹⁰Po 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.Bagnall, p. 204. The use of natural rubber gloves is not recommended for handling ²¹⁰Po solutions.

Despite the element's highly hazardous properties, circumstances in which polonium poisoning can occur are rare. Its extreme scarcity in nature,{{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}} 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.{{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 }}

In response to concerns about the risks of occupational polonium exposure, quantities of ²¹⁰Po 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.{{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}} ²¹⁰Po 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 μCi kg⁻¹) approached fatal quantities.{{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}}

The first documented death directly resulting from polonium poisoning occurred in the Soviet Union, on 10 July 1954.{{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}}{{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 }} 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 ²¹⁰Po had depressurised and begun to disperse in aerosol form. Over this period, his total intake of airborne ²¹⁰Po was estimated at 0.11 GBq (almost 25 times the estimated LD₅₀ by inhalation of 4.5 MBq). Despite treatment, his condition continued to worsen and he died 13 days after the exposure event.

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.{{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 }}

As well, several deaths in Israel during 1957–1969 have been alleged to have resulted from ²¹⁰Po exposure.{{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}} A leak was discovered at a Weizmann Institute laboratory in 1957. Traces of ²¹⁰Po 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 cancers 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.{{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}}

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.{{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}}

{{Further|Poisoning of Alexander Litvinenko|Cause of Yasser Arafat's death}}

The cause of the 2006 death of Alexander Litvinenko, a former Russian FSB agent who had defected to the United Kingdom in 2001, was identified to be poisoning with a lethal dose of ²¹⁰Po;{{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}}{{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}} it was subsequently determined that the ²¹⁰Po had probably been deliberately administered to him by two Russian ex-security agents, Andrey Lugovoy and Dmitry Kovtun.{{cite web|url=https://www.litvinenkoinquiry.org/report|publisher=The Litvinenko Inquiry|title=Report|access-date=21 January 2016}}{{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}} 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.{{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}}{{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}}{{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 }}

In 2011, an allegation surfaced that the death of Palestinian leader Yasser Arafat, who died on 11 November 2004 of uncertain causes, also resulted from deliberate polonium poisoning,{{cite news|date=17 January 2011|title=الأخبار – ضابط فلسطيني: خصوم عرفات قتلوه عربي|publisher=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}}{{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 |date=21 January 2016 |time=1:53 |access-date=28 March 2018}}{{cbignore}} and in July 2012, concentrations of ²¹⁰Po many times more than normal were detected in Arafat's clothes and personal belongings by the Institut de Radiophysique in Lausanne, Switzerland.{{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}}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. Even though Arafat's symptoms were acute gastroenteritis with diarrhoea and vomiting,{{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}} the institute's spokesman said that despite the tests the symptoms described in Arafat's medical reports were not consistent with ²¹⁰Po poisoning, and conclusions could not be drawn. In 2013 the team found levels of polonium in Arafat's ribs and pelvis 18 to 36 times the average,{{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}}{{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}} even though by this point in time the amount had diminished by a factor of 2 million.{{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. 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." Subsequently, French and Russian teams claimed that the elevated ²¹⁰Po levels were not the result of deliberate poisoning, and did not cause Arafat's death.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.{{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}}

It has also been suspected that Russian businessman Roman Tsepov was killed with polonium. He had symptoms similar to Aleksander Litvinenko.{{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}}

It has been suggested that chelation agents, such as British anti-Lewisite (dimercaprol), can be used to decontaminate humans.{{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}} In one experiment, rats were given a fatal dose of 1.45 MBq/kg (8.7 ng/kg) of ²¹⁰Po;

all untreated rats were dead after 44 days, but 90% of the rats treated with the chelation agent

HOEtTTC remained alive for five months.{{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

}}

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.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.

Polonium-210 is widespread in the biosphere, including in human tissues, because of its position in the 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.{{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}}{{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}}{{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}}

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.Lacassagne, A. & Lattes, J. (1924) Bulletin d'Histologie Appliquée à la Physiologie et à la Pathologie, 1, 279. 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{{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}} and that similar patterns of distribution occur in human tissues.{{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 }} 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.{{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}}

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.{{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}}{{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}}{{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.}}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

The presence of polonium in tobacco smoke has been known since the early 1960s.{{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 }}{{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}} 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.

Polonium is found in the food chain, especially in seafood.{{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}}{{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}}

Polonium poisoning has been used as a plot point on the American daytime television show General Hospital for many years.{{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}}

• Polonium halo
• Poisoning of Alexander Litvinenko

{{Reflist|30em}}

• {{cite book |title=Advances in Inorganic Chemistry and Radiochemistry |chapter=The Chemistry of Polonium |ref=Bagnall|last1=Bagnall |first1=K. W. |date=1962 |publisher=Academic Press |location=New York |isbn=978-0-12-023604-6|doi=10.1016/S0065-2792(08)60268-X|pages=197–226 |access-date=June 14, 2012 |chapter-url=https://books.google.com/books?id=8qePsa3V8GQC&pg=PA212|volume=4}}
• {{cite book|ref=Greenwood|author=Greenwood, Norman N.|author2=Earnshaw, Alan |date=1997|title= Chemistry of the Elements|edition= 2nd|publisher= Butterworth–Heinemann|isbn=978-0080379418}}

{{Commons|Polonium}}

{{Wiktionary|Polonium}}

• [http://www.periodicvideos.com/videos/084.htm Polonium] at The Periodic Table of Videos (University of Nottingham)

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