西南涌流域底泥重金属污染特征及潜在生态危害评价

西南涌流域近年来受到比较严重的污染,为了解受重金属污染状况,对该流域底泥重金属污染水平与特征进行了调查与分析,并在此基础上采用地累积指数法和潜在生态危害指数法对西南涌流域底泥重金属污染程度与生态危害进行了评价。结果表明,西南涌流域底泥已不同程度受到重金属Cu、Zn、Pb、Cd、Cr的污染,与珠三角土壤背景值相比,西南涌流域底泥重金属Cu、Zn、Pb、Cd、Cr分别超标11.38、3.32、1.81、19.45、3.20倍;底泥中的Cu、Zn、Cr、Cd之间呈极显著正相关(r=0.615~0.964)。通过地累积指数法评价表明,西南涌流域底泥中的Cd为偏重污染,Cu、Zn为偏中度污染,Pb为轻度污染,Cr为无污染;潜在生态危害指数法评价结果表明,西南涌流域底泥重金属的潜在生态危害程度总体属中等,主要是由Cd的含量过高引起。

Investigation of Heavy Metal Pollution Characteristics and Potential Ecological Risk Assessment in Sediment of Xinan River Watershed

The Xinan River watershed is seriously polluted in recent years. In order to understand the extend of pollution by heavy metal for the sediment in Xinan River. Investigations and analysis is conducted to figure out the characteristics and the extend of pollution in the river sediment by heavy metal. On the basis, several methods including geo-accumulation index and potential ecological risk index are employed for analysis of the degree of contamination and ecological risk of Xinan river watershed sediment. The results indicated that Xinan river watershed sediment has been contaminated inordinately by Cu, Zn, Pb, Cd and Cr, and the contents of Cu, Zn, Pb, Cd and Cr were 11.38, 3.32, 1.81,19.45 and 3.20 times higher than the Pearl River Delta soil background values, respectively. Additionally, the three heavy metals Cu, Zn, Cr and Cd in sediment showed a very significant positive correlation(r=0.615-0.964). The results came out from geo-accumulation index method indicated that Cd has already on slightly serious-pollution state, while Cu and Zn in the state of mid-pollution, Pb in the state of light-pollution, and Cr in the state of no-pollution. The results from potential ecological risk index method demonstrated that the potential ecological hazardous of heavy metal have medium negative effect on Xinan River sediment, and it is mainly attributed to the too high content of Cd in the sediment.