辽宁省大凌河口沉积物重金属污染及生态风险评价

Pollution and potential ecological risk evaluation of heavy metals in surface sediment from Daling River Estuary,Liaoning Province

分析了大凌河河口地区30个表层沉积物样品中七种重金属(Pb、Cr、Hg、As、Cd、Cu、Zn)含量分布特征,同时对环境中重金属的生态风险进行了评价。结果表明:造纸厂排污口(Sew)表层沉积物中重金属污染较为严重,并且显著影响(P<0.05)其下游流域环境中重金属的含量;河口湿地对陆源污染物向海洋排放具有一定的缓冲作用;经相关性分析,七种重金属表现出污染的同源性(P<0.01)。利用潜在生态风险指数法对大凌河河口地区的潜在生态风险进行评价,该地区重金属的潜在生态风险系数由大至小排序为:Hg>Cd>As>Cu>Pb>Cr>Zn,Hg是主要潜在生态风险因子;排污口(Sew)和锦州湾(B01)点位处于中度生态风险,其它区域处于低生态风险范畴。

Thirty surface sediment samples collected from the Daling River Estuary, Liaoning Province were analyzed for 7 heavy metals （ Pb, Cr, Hg, As, Cd, Cu, Zn ） and their potential ecological risk was evaluated. The results showed that the highest concentration of heavy metal in sediment was found in the sampling site located at the outlet of a sewage of a paper mill, and those heavy metals re- leased from the sewage influenced significantly the concentrations of heavy metals in surface sediment in its downstream river basin （P 〈0.05）. Estuary has fine buffer action to delay and reduce urban contaminants entering the sea. Analysis of variance indicated seven heavy metal pollutants from the same source （ P 〈 0.01 ）. The potential ecological risk of the heavy metals in the surface sedi- ments was evaluated, which showed that potential ecological risk of these heavy metals followed the order of Hg 〉 Cd 〉 As 〉 Cu 〉 Pb 〉 Cr 〉 Zn, and Hg was the main potential ecological risk factor. The surface sediments possessed light potential ecological risk except those at the sewage （Sew） and Jinzhou Bay （B01） sampling sites.