三峡库区大宁河与磨刀溪重金属污染特征

为揭示三峡库区重金属污染的潜在风险,分析了三峡库区大宁河和磨刀溪两条典型支流沉积物和野生鲫鱼体内重金属水平,并分别采用潜在生态危害指数法和综合污染指数法对重金属污染风险进行了评价.结果表明,沉积物中Zn和Cr含量均处于较高水平(大宁河:78.31和83.98 mg.kg-1;磨刀溪:99.03和94.20 mg.kg-1),而Cd含量水平最低(大宁河:0.62mg.kg-1;磨刀溪:0.75 mg.kg-1),并从上游到下游表现为明显的升高趋势.野生鲫鱼各组织以肌肉中各种重金属水平最低,肠最高,但在2条支流中均没有表现出上下游的变化趋势.潜在生态危害指数法评价沉积物重金属污染处于较高风险,综合污染指数法评价鱼体重金属污染的风险低于背景值.

Characteristics of Heavy Metal Pollution in Daninghe River and Modaoxi River of Three Gorges Reservoir Areas

In order to explore the potential ecological risk of heavy metals in Three Gorges Reservoir areas, the present study analyzed the heavy metals in sediments and wild crucain carp from Daning River and Modaoxi River which are two typical tributaries, and then the potential risk was evaluated using potential ecological risk index for sediments and comprehensive pollution index for fish, respectively. The results showed that concentrations of Zn and Cr were higher (Daning River: 78.31 and 83.98 mg ·kg^-1; Modaoxi River: 99.03 and 94.20 mg ·kg^-1), while Cd was the lowest (Daning River: 0.62 mg ·kg^-1; Modaoxi River: 0.75 mg ·kg^-1). Moreover, an obvious increasing trend of these elements was observed in these tributaries from upstream to downstream. For the wild crucain carp, the lowest concentrations of these elements were detected in muscles, and the highest concentrations were in the intestinal. However, no obvious increasing trend of these elements was observed from upstream to downstream. The potential ecological risk in sediments showed a high risk, while no risk was observed in fish.