小清河干流底质有毒金属形态分布

以小清河干流底质为研究对象，为了更好地了解固体颗粒物上有毒金属被浸取进入液相情况．分析了三种不同浸取剂(DTPA、EDTA、NTA)的提取液中有毒金属Pb、Cr、Cu、Zn、Cd的含量。结果表明．金属浓度因浸取剂种类及金属本身类型不同而不同。由于固体颗粒物上金属的毒性及其可流动性与其存在形态密切相关。选取连续浸取法来考察底质样品中金属形态分布情况。结果表明．底质中Pb主要以氧化物键合态和碳酸键合态存在；Cr主要以有机键合态存在；Cu以有机键合态为优势存在；Zn主要以有机键合态和氧化物键合态存在；Cd主要以可交换态存在。

Speciation Distribution of Toxic Metal Associated with Substance Underwater of the Main Branch of Xiaoqing River

In this paper,the substance underwater of the main branch of Xiaoqing River was the research object.In order to get a better understanding of toxic metal extraction from solid particulates,three different extractants(DTPA,EDTA and NTA)were used to analyze various toxic metal contents,such as lead,chromium,copper,zinc and cadmium.In general,dominant metal concentrations were different,depending on the type of extractans and metals.Because metal speciation is closely related to toxicity and mobility,sequential extraction procedures were carried out to explore the metal speciation in the substance underwater.It was indicated that the oxide associated and the carbolic acid associated were the main existing forms for lead, the organic associated for chromium,the organic associated for copper,the organic associated and the oxide associated for zinc,and the exchangeable speciation for cadmium.