长江下游沉积物中重金属污染现状与特征

Heavy Metals in Surface Sediments from Lower Reach of the Yangtze River

对长江下游沉积物中的重金属Co、Cr、Cu、N i、Pb、Zn、Mn、Hg和As进行全量和醋酸提取态(包括水溶态、可交换态和碳酸盐结合态)分析。结果表明,大部分重金属主要来源于地壳元素的自然释放,但Cu、Zn、Hg和As在最近十几年因受到人为排放的影响质量比有所增加。长江江苏段的重金属质量比普遍高于入海口上海段;位于悬浮物易沉降地区的靖江重金属质量比明显偏高。Cu和Zn总体质量比较高,且醋酸提取态所占比例较大,对长江下游存在潜在的生态风险。

Surface sediments in lower reach of the Yangtze River, collected in 2004 and 2005, were analyzed for heavy metals including Co, Cr, Cu, Ni, Pb, Zn, Hg and As. The whole concentration and their first fraction （including exchangeable, water and acid soluble phase） of BCR sequential extraction were analyzed using ICP-MS. Results showed that most heavy metals come from natural release of earth element, while increased concentration of Cu, Zn, Hg and As demonstrated anthropogenic inputs. The levels of heavy metals in upper basin were higher than that near the Yangtze estuary. Jingjiang, a deposition zone, showed combined pollution of heavy metals. At last Cu and Zn with both high whole concentration and bioavailability had potential ecosystem risk to lower reach of the Yangtze River.