Editing Caesium (section)

==Health and safety hazards==
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[[File:AirDoseChernobylVector.svg|thumb|right|upright=1.4|alt=Graph of percentage of the radioactive output by each nuclide that form after a nuclear fallout vs. logarithm of time after the incident. In curves of various colours, the predominant source of radiation are depicted in order: Te-132/I-132 for the first five or so days; I-131 for the next five; Ba-140/La-140 briefly; Zr-95/Nb-95 from day 10 until about day 200; and finally Cs-137. Other nuclides producing radioactivity, but not peaking as a major component are Ru, peaking at about 50 days, and Cs-134 at around 600 days.|The portion of the total radiation dose (in air) contributed by each isotope plotted against time after the [[Chernobyl disaster]]. Caesium-137 became the primary source of radiation about 200 days after the accident.<ref>Data from [https://archive.org/details/TheRadiochemicalManual The Radiochemical Manual] and Wilson, B. J. (1966) ''The Radiochemical Manual'' (2nd ed.).</ref>]]
Nonradioactive caesium compounds are only mildly toxic, and nonradioactive caesium is not a significant environmental hazard. Because biochemical processes can confuse and substitute caesium with [[potassium]], excess caesium can lead to [[hypokalemia]], [[heart arrhythmia|arrhythmia]], and acute [[cardiac arrest]], but such amounts would not ordinarily be encountered in natural sources.<ref>{{cite journal |last1=Melnikov |first1=P. |last2=Zanoni |first2=L. Z. |title=Clinical effects of cesium intake. |journal=Biological Trace Element Research |date=June 2010 |volume=135 |issue=1–3 |pages=1–9 |pmid=19655100 |doi=10.1007/s12011-009-8486-7 |bibcode=2010BTER..135....1M |s2cid=19186683}}</ref><ref>{{cite journal |doi=10.1080/10934528109375003 |title=Cesium in mammals: Acute toxicity, organ changes and tissue accumulation |date=1981 |last1=Pinsky |first1=Carl |first2=Ranjan |first3=J. R. |first4=Jasper |first5=Claude |first6=James |journal=Journal of Environmental Science and Health, Part A |volume=16 |pages=549–567 |last2=Bose |last3=Taylor |last4=McKee |last5=Lapointe |last6=Birchall |issue=5|bibcode=1981JESHA..16..549P }}</ref>

The [[median lethal dose]] (LD<sub>50</sub>) for [[caesium chloride]] in mice is 2.3&nbsp;g per kilogram, which is comparable to the LD<sub>50</sub> values of [[potassium chloride]] and [[sodium chloride]].<ref>{{cite journal |doi=10.1016/0041-008X(75)90216-1 |title=Acute toxicity of cesium and rubidium compounds |date=1975 |last1=Johnson |first1=Garland T. |journal=[[Toxicology and Applied Pharmacology]] |volume=32 |pages=239–245 |pmid=1154391 |first2=Trent R. |first3=D. Wagner |issue=2 |last2=Lewis |last3=Wagner|bibcode=1975ToxAP..32..239J }}</ref> The principal use of nonradioactive caesium is as caesium formate in petroleum [[drilling fluid]]s because it is much less toxic than alternatives, though it is more costly.<ref name="Down"/>

Elemental caesium is one of the most reactive elements and is highly [[explosive material|explosive]] in the presence of water. The hydrogen gas produced by the reaction is heated by the thermal energy released at the same time, causing ignition and a violent explosion. This can occur with other alkali metals, but caesium is so potent that this explosive reaction can be triggered even by cold water.<ref name="USGS"/>

It is highly [[pyrophoricity|pyrophoric]]: the [[autoignition temperature]] of caesium is {{convert|−116|C}}, and it ignites explosively in air to form [[caesium hydroxide]] and various oxides. Caesium hydroxide is a very strong [[base (chemistry)|base]], and will rapidly corrode glass.<ref name="RSC">{{cite web |url=http://www.rsc.org/periodic-table/element/55/caesium |access-date=27 September 2010 |publisher=Royal Society of Chemistry |title=Chemical Data – Caesium – Cs |archive-date=23 November 2021 |archive-url=https://web.archive.org/web/20211123105622/https://www.rsc.org/periodic-table/element/55/Caesium |url-status=live }}</ref>

The [[isotope]]s [[Caesium-134|134]] and 137 are present in the [[biosphere]] in small amounts from human activities, differing by location. Radiocaesium does not accumulate in the body as readily as other fission products (such as radioiodine and radiostrontium). About 10% of absorbed radiocaesium washes out of the body relatively quickly in sweat and urine. The remaining 90% has a biological half-life between 50 and 150 days.<ref>{{cite journal |journal=British Journal of Radiology |title=A Survey of the Metabolism of Caesium in Man |date=1964 |last1=Rundo |issue=434 |pages=108–114 |doi=10.1259/0007-1285-37-434-108 |pmid=14120787 |first1=J. |volume=37}}</ref> Radiocaesium follows potassium and tends to accumulate in plant tissues, including fruits and vegetables.<ref>{{cite journal |doi=10.1007/BF01376226 |title=Accumulation of Cs and K and growth of bean plants in nutrient solution and soils |date=1962 |last1=Nishita |first1=H. |last2=Dixon |first2=D. |last3=Larson |first3=K. H. |journal=Plant and Soil |volume=17 |pages=221–242 |issue=2 |bibcode=1962PlSoi..17..221N |s2cid=10293954}}</ref><ref>{{cite journal |doi=10.1016/0265-931X(96)89276-9 |title=Fate of caesium in the environment: Distribution between the abiotic and biotic components of aquatic and terrestrial ecosystems |date=1996 |last1=Avery |first1=S. |journal=Journal of Environmental Radioactivity |volume=30 |pages=139–171 |issue=2|bibcode=1996JEnvR..30..139A }}</ref><ref>{{cite journal |doi=10.1039/AN9921700487 |title=Availability of caesium isotopes in vegetation estimated from incubation and extraction experiments |journal=Analyst |date=1992 |volume=117 |pages=487–491 |first1=Brit |last1=Salbu |first2=Georg |last2=Østby |first3=Torstein H. |last3=Garmo |first4=Knut |last4=Hove |pmid=1580386 |issue=3 |bibcode=1992Ana...117..487S}}</ref> Plants vary widely in the absorption of caesium, sometimes displaying great resistance to it. It is also well-documented that mushrooms from contaminated forests accumulate radiocaesium (caesium-137) in the fungal [[sporocarp (fungi)|sporocarps]].<ref>{{cite journal |url=https://www.researchgate.net/publication/42541094 |doi=10.1016/j.scitotenv.2010.02.024 |pmid=20334900 |title=Accumulation of potassium, rubidium and caesium (<sup>133</sup>Cs and <sup>137</sup>Cs) in various fractions of soil and fungi in a Swedish forest |journal=Science of the Total Environment |volume=408 |issue=12 |year=2010 |pages=2543–2548 |last1=Vinichuk |first1=M. |bibcode=2010ScTEn.408.2543V |access-date=30 October 2017 |archive-date=4 April 2023 |archive-url=https://web.archive.org/web/20230404171121/https://www.researchgate.net/publication/42541094 |url-status=live }}</ref> Accumulation of caesium-137 in lakes has been a great concern after the [[Chernobyl disaster]].<ref name="smithber05">{{cite book |first1=Jim T. |last1=Smith |first2=Nicholas A. |last2=Beresford |title=Chernobyl: Catastrophe and Consequences |date=2005 |publisher=Springer |place=Berlin |isbn=978-3-540-23866-9}}</ref><ref>{{cite journal |doi=10.1007/BF02197418 |title=Radioactive isotopes of caesium in the waters and near-water atmospheric layer of the Black Sea |first1=V. N. |last1=Eremeev |first2=T. V. |last2=Chudinovskikh |first3=G. F. |last3=Batrakov |first4=T. M. |last4=Ivanova |volume=2 |issue=1 |date=1991 |journal=Physical Oceanography |pages=57–64 |s2cid=127482742}}</ref> Experiments with dogs showed that a single dose of 3.8 [[curie (unit)|millicuries]] (140&nbsp;[[Becquerel|MBq]], 4.1&nbsp;μg of caesium-137) per kilogram is lethal within three weeks;<ref>{{cite journal |title=Toxicity of 137-CsCl in the Beagle. Early Biological Effects |first1=H. C. |last1=Redman |first2=R. O. |last2=McClellan |first3=R. K. |last3=Jones |first4=B. B. |last4=Boecker |first5=T. L. |last5=Chiffelle |first6=J. A. |last6=Pickrell |first7=E. W. |last7=Rypka |volume=50 |issue=3 |date=1972 |journal=Radiation Research |pages=629–648 |doi=10.2307/3573559 |pmid=5030090 |jstor=3573559 |bibcode=1972RadR...50..629R}}</ref> smaller amounts may cause infertility and cancer.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/asia-pacific/7967285.stm |title=Chinese 'find' radioactive ball |publisher=BBC News |date=27 March 2009 |access-date=25 January 2010 |archive-date=10 October 2021 |archive-url=https://web.archive.org/web/20211010060059/http://news.bbc.co.uk/2/hi/asia-pacific/7967285.stm |url-status=live }}</ref> The [[International Atomic Energy Agency]] and other sources have warned that radioactive materials, such as caesium-137, could be used in radiological dispersion devices, or "[[dirty bomb]]s".<ref>{{cite news |last=Charbonneau |first=Louis |title=IAEA director warns of 'dirty bomb' risk |newspaper=The Washington Post |page=A15 |url=http://www.highbeam.com/doc/1P2-250680.html |agency=Reuters |date=12 March 2003 |access-date=28 April 2010 |archive-url=https://web.archive.org/web/20081205004052/http://www.highbeam.com/doc/1P2-250680.html |archive-date=5 December 2008 |url-status=dead}}</ref><!-- 10.1016/S0098-8472(01)00124-1-->