中山市主要灌溉水源底泥重金属污染及潜在生态风险评估

Heavy Metal Pollution in Sediments of Main Irrigation Water Sources in Zhongshan City and Its Potential Ecological Risk Assessment

[目的]评估灌溉水源底泥重金属污染水平及其潜在的生态风险。[方法]在广东省中山市主要灌溉水源洪奇沥和横琴海沿线采集6个底泥样品,测定Pb、Cd、Cr、As、Hg 5种重金属的含量水平,分析其分布特征,并采用综合指数法、地累积指数法和潜在生态危害指数法对底泥中重金属污染状况和潜在生态风险进行了评价。[结果]中山市主要灌溉水源底泥存在重金属复合污染情况,样品中Pb、Cd、Cr、As、Hg含量均高于参比值,洪奇沥底泥中,5种重金属富集程度从大到小依次为Hg、Cd、Cr、Pb、As,横琴海底泥中,5种重金属富集程度从大到小依次为Cd、Cr、Hg、As、Pb,5种重金属潜在生态危害从大到小依次为Hg、Cd、Cr、As、Pb,处于轻微生态风险等级。[结论]中山市洪奇沥和横琴海2条主要灌溉水源底泥存在多种重金属复合污染,污染水平处于中度至重度污染,工业园区废水排放是重金属污染的主要原因之一。

[Objective] The aim was to discuss heavy metal pollution level in sediments of irrigation water sources and its potential ecological risk. [ Method] Collecting 6 sediment samples from Hongqili and Hengqinhai in Zhongshan City in Guangdong Province, Pb, Cd, Cr, As, Hg content was determined and distribution characteristics were analyzed. By using comprehensive index method, land accumulation index method and potential ecological harm index method, the heavy metal pollution status in sediments and potential ecological risk were evaluated. [ Result] There was heavy metal compound pollution situation in sediments, the content of Pb, Cd, Cr, As, Hg in the samples was higher than reference value. In sediment of Hongqili, the order of heavy metal enrichment degree was Pb, Cd,Cr,Hg,As, in sediment of Hengqinhai, the order of enrichment degree was Cd〉Cr〉Hg〉As〉Pb, the order of potential ecological harm was Hg,Cd,Cr,As,Pb, which was in light eco-logical risk grade. [Conclusion] There are many kinds of heavy metal pollution in the sediment of 2 main irrigation water sources（Hongqili and Hengqinhai） in Zhongshan. The pollution level is at moderate to severe pollution, wastewater discharge of industrial park is one of the main reasons for heavy metal pollution.