太湖流域河流沉积物重金属分布及污染评估

为阐明经济发达地区河流表层沉积物重金属的污染特征,本研究分析了太湖流域典型水系94个样点沉积物中8种重金属(Zn、Cr、Ni、Cu、Pb、As、Cd和Hg)含量,评估了重金属的生态风险以及辨析了污染来源.结果表明,太湖流域河流表层沉积物中Zn、Cr、Ni、Cu、Pb、As、Cd和Hg的平均含量分别为163. 62、102. 46、45. 50、44. 71、37. 00、13. 34、0. 479和0. 109 mg·kg~(-1),均高于其对应的背景值(Hg除外).地累积指数评价中,Pb、Ni、Zn、Cu和Cd整体上处于低污染状态;在污染负荷指数评价中,Pb、Ni、Zn和Cu整体上处于中度污染状态,Cd、Cr、As处于低污染状态;在潜在生态风险评价中,Cd和Hg处于中等潜在生态风险,其余重金属均处于低潜在生态风险.多元统计分析表明,Pb主要来自于生活污水、农业废水排放;除受自然因素影响外,Cr、Ni和Zn还受到电镀及合金制造行业的影响; Cu和As主要来自于农药、工业废水; Cd主要来自于冶炼工业; Hg主要来源于化石燃料和石油产品的燃烧.

Spatial Distribution and Pollution Assessment of Heavy Metals in River Sediments from Lake Taihu Basin

To clarify the pollution characteristics of heavy metals in the surface sediments of rivers in economically developed areas, analysis of the contents of eight heavy metals, assessment of ecological risks, and identification of the source of heavy metals in surface sediments from typical rivers of Lake Taihu Basin were carried out in this study. The results showed that the average contents of Zn, Cr, Ni, Cu, Pb, As, Cd, and Hg in the surface sediments of Lake Taihu Basin were 163.62, 102.46, 45.50, 44.71, 37.00, 13.34, 0.479, and 0.109 mg·kg^-1, respectively. Except for Hg, the average contents of other 7 heavy metals were higher than their background values. The geo-accumulation index indicated that Pb, Ni, Zn, Cu, and Cd amount to a low pollution state. According to the pollution load index, Pb, Ni, Zn, and Cu represent a moderately polluted state, while Cd, Cr, and As a low degree pollution state. Based on the potential ecological risk index, Cd and Hg represent moderate potential ecological risk, and the others low potential ecological risk. Source identification of heavy metals by multivariate statistical analysis showed that Pb was largely from non-point pollutions; Cr, Ni, and Zn stemmed from electroplating, alloy manufacturing industries, and nature; Cu and As were mainly from pesticides and discharge of industrial wastewater; Cd was dominantly from smelting industry; and Hg was mainly derived from fossil fuel combustion and petroleum products.