キレート樹脂固相抽出法を併用したICP質量分析法による下水処理施設周辺環境水の超高感度多元素分析

抄録

Analytical method for the determination of major-to-ultratrace elements in environmental water samples around sewage treatment plant by ICP-MS was examined in detail. In the present work, solid phase extraction using chelating-resin was adopted as the preconcentration method for the determination of ultratrace elements. Prior to solid phase extraction, environmental water samples were heated with nitric acid and hydrogen peroxide at 200 °C for 4h to decompose chelating agents contained in sewage effluent such as EDTA, which cause low recovery values for several elements. As a result, 53 elements in the concentration range from sub-ng/L to several 10 mg/L could be determined with good reproducibility. The reliability of the whole analytical procedure was confirmed by analyzing river water certified reference materials (JSAC 0301-4a and JSAC 0302-4a). From the analytical results for environmental water (river water) samples around sewage treatment plant (upstream, just below outlet, downstream 1 and downstream 2), it was found that various elements such as Fe, Co, Ni, Cu, Zn, Cd, and Pb were emitted from sewage effluent into environmental water (river water) as dissolved forms, while the element existed mainly in particulate matters (Al, Ti, and rare earth elements) showed low concentrations in sewage effluent. Distribution patterns of rare earth element for sewage effluent and downstream samples showed characteristic large Gd anomalies and increase from light REE to heavy REE, which were the same as other environmental water samples affected by the influx of sewage effluent.