东江流域底泥重金属分析及潜在环境生态风险

The analysis and pollution assessment of heavy metals in the sediment of the East River

对东江流域不同江段水环境的重金属底泥及底泥浸出液中铅、锌、铜、镉、铬、镍等重金属分布进行分析,结果表明铅和镉含量较高,存在一定程度污染或属于高背景值底泥;底泥的重金属因沉积引起,而锌、铜、铬和镍含量具有一定的污染同源性;利用地积累指数法和潜在生态风险指数法评价底泥重金属污染状况,镉污染较为严重,潜在生态风险大,污染程度镉>铜>锌>镍,铅存在一定的潜在生态风险,铅和铬污染风险较小,底泥和底泥浸出液中重金属含量的变化趋势较为一致,结果表明底泥是表面水重金属的重要来源.

The concentrations of Pb,Zn,Cu,Cd,Cr and Ni in the sediment and the sediment elutriate samples from different sites of Dongjiang River were analyzed.The results indicate high Pb and Cd content,suggesting certain degree of pollution or high background value in the sediment.The contamination of Zn,Cu,Cr and Ni in the sediment may be from the same source.Using the geoaccumulation index of Muller and the potential ecological risk index of Hakanson,the data show that the pollution of Cd is severe,and its potential ecological risk is high.The extent of risk ranks as CdCuZnNi,and there is hardly any pollution caused by Pb and Cr.However,Pb has potential ecological risk.The concentration of heavy metals in the sediment and sediment elutriate is correlated,indzcating that the sediment is the key source of heavy metals in surface water.