Biomethylation of Arsenic in an Arsenic-rich Freshwater Environment

✍ Scribed by Toshikazu Kaise; Mitsuo Ogura; Takao Nozaki; Kazuhisa Saitoh; Teruaki Sakurai; Chiyo Matsubara; Chuichi Watanabe; Ken'ichi Hanaoka

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 98 KB
• Volume: 11
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199704)11:4<297::aid-aoc584>3.0.co;2-0

✦ Synopsis

Arsenic circulation in an arsenic-rich freshwater ecosystem was elucidated to detect arsenic species in the river water and in biological samples living in the freshwater environment. Water-soluble arsenic compounds in biological samples were extracted with 70% methanol. Samples containing arsenic compounds in the extracts were treated with 2 mol dm Ϫ 3 of sodium hydroxide and reduced with sodium borohydride. The detection of arsenic species was accomplished using a hydride generation/cold trap/cryofocus/gas chromatography-mass spectrometry (HG/ CT/CF/GC-MS) system. The major arsenic species in the river water, freshwater algae and fish are inorganic arsenic, dimethylarsenic and trimethylarsenic compounds, respectively. Trimethylarsenic compounds are also detected in aquatic macro-invertebrates. The freshwater unicellular alga Chlorella vulgaris, in a growth medium containing arsenate, accumulated arsenic and converted it to a dimethylarsenic compound. The water flea Daphnia magna, which was fed on arsenic-containing algae, converted it to a trimethylarsenic species.