长江南京段沉积物中铜、镉形态对水生生物富集的影响

 为了全面定量地考察沉积物中各种金属结合形态对不同水生生物富集的影响，运用重金属逐级提取法及采用人工半合成方法，对长江南京段沉积物中铜、镉形态分布不同的情况下鲤鱼和螺蛳对这两种重金属的富集进行了研究。结果表明，沉积物通过对溶解态的贡献间接影响鲤鱼对铜、镉的富集，对螺蛳富集铜、镉同时有直接和间接影响，大小顺序为：阳离子可交换态≥碳酸盐结合态＞有机物和硫化物结合态＞铁锰氧化物结合态＞残渣态。并得出了溶解态和沉积物各态对螺蛳富集铜、镉影响的贡献方程式，指出离子可交换态对富集的贡献比残渣态大10⁵倍。据此可以认为，为了减少受重金属污染河流中水生生物体内的富集量，对生活在水上、中层的鱼类来说，主要应控制水中的重金属浓度；对底栖生物来说，水和沉积物中重金属浓度都应受到控制。

The Cu and Cd species in sediment of the Nanjing reach of Changjiang River,and their bioavailability to aquatic organisms

Cu and Cd content in sediment of the Nanjing reach of Changjiang River were determined with the sequential extraction procedure. The accumulation tests of Cu and Cd in carp and snail were studied in vitro with the solution containing semisynthetic sediment samples. The results show that, for carp, the accumulations of Cu and Cd are related to the concentration of dissolved metal which in turn is affected by the distribution of species in sediment under given environmental condition; For snail, various species of metal in sediment can contribute directly to accumulation. The contribution of ionexchangable species is 105times larger than that of residual species in sediment. It is inferred that, for reducing the heavy metal accumulation of aquatic organisms in polluted river, the metal concentrations in water should be controlled for fish, while in both water and sediment for benthon organism.