东莞水库底泥重金属污染及潜在生态风险评价

Pollution Characteristics and Potential Ecological Risk Assessment of Heavy Metals in Sediments from Eight Reservoirs of Dongguan City

对东莞市8座水库共计60个底泥剖面中的Cd、Hg、Zn、Cu、Ni、As、Pb、Cr 8种重金属含量进行分析,并采用内梅罗综合污染评价法和潜在生态危害指数评价法对底泥重金属污染情况与潜在生态危害进行评价。底泥重金属含量普遍存在表层>中层>底层的关系,表明近期内水库水体污染较重,尚未完全切断污染源。根据内梅罗综合污染评价,8座水库底泥中重金属指标大部分已处于Ⅳ级污染状态,底泥重金属污染程度由高至低的顺序为:Cd?Zn>Hg>Ni>Pb>As>Cr>Cu;根据潜在生态危害指数评价,8座水库均表现出很强的潜在生态危害,底泥重金属潜在生态危害由强到弱的顺序为:Cd?Hg?As>Pb>Ni>Cu>Zn>Cr。

The concentrations of Cd, Hg, Zn, Cu, Ni, As, Pb and Cr in sediments from eight reservoirs in Dongguan City were analyzed, the pollution condition and potential ecological risk of heavy metals were evaluated through Nemerow comprehensive pollution evaluation method and potential ecological risk index evaluation method.The concentrations of heavy metals in surface sediments are higher than that in middle and bottom layer. The result shows that the pollution of the reservoirs in the near future is not completely cut off. According to Nemerow comprehensive pollution assessment, most of the heavy metals in sediments have reached the GradeⅣpollution, which followed the descend order as Cd〉Zn〉Hg〉Ni〉Pb〉As〉Cr〉Cu. According to potential ecological risk index evaluation, they all showed strong potential ecological risk, and the potential ecological risks degree of heavy metals followed the descend order as Cd〉Hg〉As〉Pb〉Ni〉Cu〉Zn〉Cr.