安庆沿江湖泊及长江安庆段沉积物重金属污染特征及生态风险评价

为研究安庆沿江湖泊及长江安庆段重金属污染特征及潜在的生态风险,采集了安庆沿江湖泊及长江安庆段沉积物样品共58个,分析了Cu、Zn、Pb和Cd共4种重金属分布特征,并采用地累积指数法和Hakanson生态危害指数法进行生态风险评价,结果表明:不同水体沉积物重金属含量差异较大,市区湖泊群内各重金属含量普遍高于周边生态湖泊和长江安庆段;与区域对应的沉积物重金属背景值比较,市区湖泊群中各类重金属普遍高于背景值,而其他水体沉积物中的重金属则与背景值相近,表明市区工业生产及生活等人类活动对湖泊沉积物重金属含量有较大影响。地累积指数污染评价表明安庆市区湖泊群受到一定程度的重金属污染,尤其是Cd污染达到了中度污染程度。总的看来,所有安庆沿江湖泊及长江安庆段沉积物中各重金属污染的程度依次为CdPbZnCu。生态风险评价表明市区湖泊群和菜子湖处于中等生态危害状态,其他水体均处于低生态风险状态,各水体潜在生态危害顺序依次为市区湖泊群、菜子湖、长江安庆段、嬉子湖、石门湖、白荡湖;研究区域沉积物中的重金属生态风险以Cd为主。

Pollution characteristics and ecological risk assessment of heavy metals in the sediments from lakes of Anqing City and Anqing section of Yangtze River

To investigate pollution characteristics and ecological risk assessment of heavy metals in the sediments from lakes of Anqing City and Anqing section of Yangtze River, the pollution characteristics of 4 heavy metals including Cu, Zn, Pb and Cd were analyzed in 58 surface sediment samples from lakes of Anqing City and Anqing section of Yangtze River, and the ecological risk assessment was evaluated using geo-accumulation index(I_geo) and potential ecological risk index(RI). Results showed that:The concentrations of heavy metals varied greatly in different lakes. The heavy metals in the urban lakes were generally higher than other detected lakes and river. Comparing with the soil background value of Yangtze River basin, the concentration of all 4 heavy metals in sediment samples from urban lakes were higher generally, while heavy metals in other sediment samples were close to the value of soil background, which means human activities such as industrial production and resident''s life in urban areas influencing on the content of heavy metals in lake sediments. I_geo also indicated that urban lakes were contaminated by heavy metals among all detected lakes and river, especially Cd, which coming up to moderate pollution. Generally, the order of heavy metal pollution in the sediments of the lakes and river in this study was Cd, Pb, Zn and Cu. The results of ecological risk assessment indicated that the ecological risk in urban lakes and Caizi Lake were in middling level, while other lakes and river were slight. The order of ecological risk in these study areas was urban lakes, Caizi Lake, Anqing section of Yangtze River, Xizi Lake, Shimen Lake and Baidang Lake. The ecological risk was dominated by Cd in all sediments in these study areas.