苍南沿浦湾滩涂重金属污染现状评价

Heavy Metal Pollution Status Assessment in Yanpu Bay Beach of Cangnan County

以温州苍南县沿浦湾滩涂土壤中的重金属含量为指标,采用环境污染指数、地累积指数和潜在生态危害指数综合评价重金属的含量水平及对生态环境的潜在影响。结果表明:沿浦湾滩涂土壤中重金属含量较低,均符合土壤环境质量二级标准。除了元素砷和汞,铜、铅、铬、锌、镉5种重金属的含量均为高潮带和中潮带高于低潮带。潜在生态危害系数和地累积指数的顺序均为砷(As)>铜(Cu)>铅(Pb)>铬(Cr)>锌(Zn)>汞(Hg)>镉(Cd);不同重金属的地累积指数的污染等级顺序为砷(As)>铜(Cu)>铅(Pb)=铬(Cr)=锌(Zn)=汞(Hg)=镉(Cd),砷(As)是主要生态风险因子;总的潜在生态风险指数为中潮带>低潮带>高潮带。综合三种评价方法,除砷在地累积指数评价中等级为无污染到中级污染,其余重金属现状评价结果均为轻微或低污染。

This study analyzed the environmental pollution index, geo-accumulation index and the potential ecological risk assessment, and evaluated the content levels of heavy metals and their potential effects on the ecological environment in Yanpu Bay Beach of Cangnan County, Wenzhou. The results showed that the low contents of different heavy metals complied with the secondary standards of soil environmental quality in the Yanpu Bay Beach. Expect for the arsenic（As） and mercury（Hg）, the contents of the other 5 heavy metal elements（copper, Cu; lead, Pb; chromium,Cr; zinc, Zn; cadmium, Cd） were higher in the high tide zone and the middle tide zone than in the low tide zone. The potential ecological risk index and the geo-accumulation index about different heavy metals decreased in the order： As〉 Cu 〉 Pb 〉 Cr 〉 Zn 〉 Hg 〉 Cd. And the pollution grade sequence of geo-accumulation index about different heavy metals decreased following the order： As 〉 Cu 〉 Pb = Cr = Zn = Hg = Cd, which showed that As was the main ecological risk factor of soil heavy metal element. The total potential ecological risk index was the highest in the middle tide zone, then in the low tide zone, the lowest in the high tide zone. Referring to the three evaluation methods,the status evaluation results of heavy metal element showed the trends of slight or low pollution, except the pollution level of As showed no pollution to moderate pollution using the geo-accumulation index evaluation.