ICP質量分析法で定量した日本の河川, 湖沼におけるインジウム, タリウム, ビスマスの濃度と外国の測定値との比較

The concentrations of indium (In), thallium (Tl) and bismuth (Bi) in rivers and lakes in Hokkaido, Kanto area, Tokai area, Shinetsu area and Kyusyu area of Japan were analyzed by ICP-MS. Five hundreds mL of samples were filtrated with 0.45μm membrane filter. The concentrations of the three elements in the filtrate were shown as soluble In, Tl and Bi. The concentrations of the three elements in the residue on the membrane filter of 0.45μm pore size were shown as filtration residue In, Tl and Bi. The averages and standard deviations (unit:ng/L) of the soluble elements were In 2.3±5.1 (n=195), Tl 8.4±17. 1 (n=195), and Bi 1.2±4.2 (n=159). Those for filtration residues were In 9.3±36. 1 (n=177), Tl 30.0±112.3(n=177), and Bi 31.0±118.7 (n=159), respectively. Although, these samples were collected in various seasons and sampling dates, the average concentration might indicate the representative concentrations of In, Tl and Bi in rivers and lakes in Japan. The results for Japanese samples were compared with the results of foreign countries.