地球化学
Online ISSN : 2188-5923
Print ISSN : 0386-4073
ISSN-L : 0386-4073
企画総説「地球化学の最前線」
ヨウ素の地球化学と微生物 : ヨウ素の揮発,濃縮,酸化,還元,吸着,脱ハロゲン化反応を触媒するバクテリア
天知 誠吾
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ジャーナル オープンアクセス

2013 年 47 巻 4 号 p. 209-219

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Iodine is one of essential trace elements for humans and animals, and is a constituent of thyroid hormones thyroxine and triiodothyronine. Insufficient iodine in the diet can cause iodine deficiency disorders such as endemic goiter and cretinism. Iodine has one stable isotope, 127I, and several radioisotopes, including 129I and 131I. From a radioecological viewpoint, long-lived 129I is of great concern because it is one of the most persistent radionuclides released into the environment from nuclear facilities and nuclear weapon testing. Given its long half-life (15.7 million years), 129I is expected to behave like a stable isotope over long time periods and it may accumulate in the human thyroid gland. Therefore, it is important to understand geochemistry of iodine for accurate safety assessments of 129I. The predominant chemical forms of iodine in the environment are iodate (IO3-; oxidation state, +5), iodide (I-; oxidation state, -1), and organically bound iodine. Recent studies have demonstrated that chemical forms of iodine are influenced or regulated by environmental organisms, especially bacteria. In this review, bacterially catalyzed iodine chemistries, including volatilization, accumulation, oxidation, reduction, sorption, and reductive dehalogenation of iodine, are summarized.

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© 2013 日本地球化学会
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