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Thallium and its compounds are often highly toxic. Contact with skin is dangerous, and adequate ventilation should be provided when melting this metal.〔(【引用サイトリンク】 Biology of Thallium )〕 Many thallium(I) compounds are highly soluble in water and are readily absorbed through the skin. Exposure to them should not exceed 0.1 mg per m2 of skin in an 8-hour time-weighted average (40-hour work week). Thallium is a suspected human carcinogen.〔 Part of the reason for thallium's high toxicity is that, when present in aqueous solution as the univalent thallium(I) ion (Tl+), it exhibits some similarities with essential alkali metal cations, particularly potassium (due to similar atomic radii). It can thus enter the body via potassium uptake pathways.〔(A Homogenous Thallium Flux Assay for High Throughput Screen of Potassium Channels )〕 Other aspects of thallium's chemistry differ strongly from that of the alkali metals, such as its high affinity for sulfur ligands. Thus this substitution disrupts many cellular processes (for instance, thallium may attack sulfur-containing proteins such as cysteine residues and ferredoxins).〔(Eliminating Thallium (poisoning) )〕 Thallium's toxicity has led to its use (now discontinued in many countries) as a rat and ant poison.〔 Among the distinctive effects of thallium poisoning are hair loss (which led to its initial use as a depilatory before its toxicity was properly appreciated) and damage to peripheral nerves (victims may experience a sensation of walking on hot coals), although the loss of hair only generally occurs in low doses; in high doses the thallium kills before this can take effect.〔Blum, The Poisoner's Handbook, 256〕 Thallium was once an effective murder weapon before its effects became understood, and an antidote (Prussian blue) discovered. Indeed, thallium poisoning has been called the "poisoner's poison" since thallium is colorless, odorless and tasteless; its slow-acting, painful and wide-ranging symptoms are often suggestive of a host of other illnesses and conditions.〔Amy Ellis Nutt & Sue Epstein, (A 15-year-old case yields a timely clue in deadly thallium poisoning ), The Star-Ledger, February 13, 2011〕 == Treatment and internal decontamination == There are two main methods of removing both radioactive and stable isotopes of thallium from humans. First known was to use Prussian blue, which is a solid ion exchange material, which absorbs thallium. Up to 20 g per day of Prussian blue is fed by mouth to the person, and it passes through their digestive system and comes out in the stool. Hemodialysis and hemoperfusion are also used to remove thallium from the blood serum. At later stage of the treatment additional potassium is used to mobilize thallium from the tissue.〔(Prussian blue fact sheet ) from the Centers for Disease Control and Prevention〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Thallium poisoning」の詳細全文を読む スポンサード リンク
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