东海大桥附近海域沉积物重金属分布特征及风险评价

东海大桥附近海域位于长江口和杭州湾的交汇地带，是长江三角洲南翼组成部分，在渔业上是一个重要的生态经济水域。本文以其为研究区域，2014年9月至2016年5月期间，采样4次，采集样品35个。分析了沉积物中Cu、Pb、Cd、Cr、Hg和As 6种重金属的时空含量变化特征，并采用地累积指数法、潜在生态危害指数法对不同时空条件下重金属的污染程度、潜在生态风险进行了评价。结果表明:东海大桥附近海域沉积物重金属空间时间分布上有一定的差异。整体来看，东海大桥附近海域沉积物基本未受重金属的污染，属于清洁状态，沉积物中重金属的含量Cr＞Pb＞Cu＞As＞Hg＞Cd。沉积物的潜在生态风险评价表明主要风险因子为Hg，应成为下一步关注重点。

Distribution characteristics and risk assessment of heavy metals in sediments of the East China Sea bridge nearby waters

Research area located in the intersection area of Yangtze RiverEstuary and Hangzhou bay waters, is part of the south of the Yangtze River Delta, which is an important ecological economic zone in the fishery.A total of 35 representative sediments were collected by four times during the period from September 2014 to May 2016.Based on the monitoring of six heavy metal elements (Cu, Pb, Cd, Cr, Hg and As) in the 35 sediments from nine samples sites, temporal and spatial variation characteristics was discussed.The pollution degrees and potential ecological risks of the heavy metals in the sediments were assessed by using geo-accumulation index (I_geo) and Hakanson potential ecological risk index.There existed obvious temporal and spatial differences in the total concentrations of the heavy metals in the marine sediments near the East China Sea bridge.In general, Marine sediments near the East China Sea bridge basic was not contaminated by heavy metals, was in relatively clean state.The result also showed that the main factors influencing potential ecological risk in sediments was Hg, which should be of great concern.