湘江霞湾港段底泥的含镉量分布研究

Distribution of Cd in sediments from Xiawan drainage area of the Xiang River

为了研究湘江霞湾港段底泥中镉的含量分布和释放特性,对该河段底泥采样以测定含镉量,并采用Tessier连续提取法对镉形态进行分析测定。结果表明,湘江霞湾港段受到严重的镉污染,其底泥含镉量最高达359.8μg/g。湘江底泥和间隙水中含镉量的吸附-解吸平衡可采用Freundlich吸附等温式描述。对新霞湾和老霞湾排污口附近河流底泥的镉形态分析表明,镉污染物以有机质-硫化物结合态为主,分别占总量的73.3%(质量分数,下同)、65.3%,其次是残渣晶格结合态,分别占总量的26.5%、34.4%。

The concentration and species distribution of Cadmium （Cd） in sediments from Xiawan drainage area of the Xiang River were determined by atomic adsorption method and Tessier sequential chemical extraction method. The obtained data demonstrated Cd contamination in Xiang River was serious, and the maximum content of Cd could reach as high as 359.8μg/g. The adsorption-desorption balance of Cd between pore water and sediments could be well described by the Freundlich adsorption isotherm. In sediment of two drainage outlets, speciation analysis of Cd indicated that 73.3% and 65.3% of Cd were respectively associated with organic substances and sulfide,and 26.5% and 34.4 % of Cd were existed in residual phase.