洪灾后高州水库表层沉积物重金属含量及污染评价

Pollution Characteristics and Potential Ecological Risk of Heavy Metals in Surface Sediments After Flood in Gaozhou Reservoir

针对2010年9月21日高州水库发生特大洪灾与泥石流,2012年4月对高州水库沉积物生态环境进行评估。其分析结果表明,高州水库表层沉积物中的9种重金属元素含量的变化趋势为w(Mn)>w(Zn)>w(Pb)>w(Cr)>w(Ni)>w(Cu)>w(As)>w(Fe)>w(Cd)。地累积指数法评价表明,高州水库中重金属污染程度强弱顺序为:Cu>Zn>Pb>Ni>Cd>Mn>Cr>As>Fe。潜在生态风险指数法评价表明,高州水库部分点位Cd生态风险评级为强,应对其来源展开进一步研究,并关注其可能存在的生物效应。与高州水库洪灾前表层沉积物重金属含量相比,9.21洪灾后新形成的沉积物受到的重金属污染在减轻。

In order to assess heavy metal ecological effect of the flood on September 21, 2010, content of nine heavy metals in surface sediment of Gaozhou Reservoir were investigated in April 2012. The results showed that the order of heavy metal content was as follow; w（Mn）〉w（Zn）〉w（Pb）〉w（Cr）〉 w（Ni）〉w（Cu）〉w（As）〉w（Fe）〉w（Cd）. The order of heavy metal pollution degree calculated by the index of geo-accumulation was Cu〉Zn〉Pb〉Ni〉Cd〉 Mn〉Cr〉As〉Fe. The result of potential ecological risk coefficients showed that Cd had strong ecological risk, and which deserved a further research on its source. The potential biological effects of high Cd content in sediment could also be focus on future study. Compared with the origin surface sediment, the heavy metal pollution of the newly formed sediment was reduced after the flood.