苏州河网区河道沉积物重金属的污染特征

Pollution characteristics of heavy metals in sediments from the river network of Suzhou City

分析测定了苏州河网区河道底泥十个剖面样点60个样品中Cu、Pb、Zn、Cr、Al、Fe、K、Mn、有机质、TP、TN、粒度、pH及含水量,采用地累积指数、生态风险指数和相关分析等方法研究其重金属污染特征.结果表明:Cu和Zn处于中或中-强度污染,Pb处于无-中污染,没有Cr污染;垂直分布特征显示:Cu和Zn污染逐年变化较为一致,Pb污染有逐年加重趋势;重金属潜在生态风险处于轻微污染状态;相关性分析显示,有机质是影响其分布的重要因素,Mn、Cr、Cu、Zn、Pb五种重金属相关性显著;通过与国内外河流、水库和湖泊沉积物中重金属含量比较,苏州河网区河道重金属的累积受多种因素影响.

Metals （including Cu, Pb, Zn, Cr, AI, Fe, K, Mn）, organic matter, total phosphorus, total nitrogen, grain size, pH and water content were analyzed and determined in sediment of sixty samples collected from selected ten sites at the river network of Suzhou City. Geo-accumulation index, potential ecological risk index and correlation analysis were employed to study the distribution and pollution pattern of heavy metals. Using the metal geo-accumulation index method, the results showed the moderate and moderate to strong contamination status of Cu and Zn, little to moderate contamination status of Pb, no contamination status of Cr in the river sediments. The results also showed that the variations of Cu and Zn with sedlmeut depth were consistent with the vertical distributions. The pollution of Pb decreased annually in the sediment cores. Heavy metal pollution in this area was in a low potential ecological risk. The correlation analysis suggested that organic matter had a great influence on the distribution of heavy metals, and Mn, Cr, Cu, Zn and Pb were positively correlated each other. Compared with sediment in other rivers, reservoirs and lakes of domestic and abroad locations, the accumulation of heavy metals in the present area are affected by muhiply factors.