长江口海域表层沉积物污染及其潜在生态风险评价

根据2004年8月份长江口海域表层沉积物的监测基础资料,采用单因子污染参数法和Hakanson前在生态风险指数法,通过分析长江口不同水域表层沉积物中典型污染要素PCB,Hg,Cd,Pb,As的质量分数,评价了长江口表层沉积物的质量状况。定量确定了长江口表层沉积物的潜在生态风险程度、主要污染因子和潜在生态风险因子;分析了近年来长江口表层沉积物总的潜在生态风险和单个污染要素的潜在生态风险的变化趋势。结果表明:长江口表层沉积物质量状况良好,各典型污染要素的质量分数值均小于背景值,典型污染要素的平均综合指数Cd为1.37,典型污染要素的污染程度由高至低顺序为As>Pb>Hg>PCB>Cd,As是主要环境污染因子;长江口各水域表层沉积物总的对水域均只具有低潜在生态风险,其由高至低的排列顺序为杭州湾北岸>长江口南支>长江口北支>长江口外;各典型污染物对水域也均只具有低潜在生态风险,其由高至低顺序为Hg>PCB>Cd>As>Pb,Hg是主要潜在生态风险因子;近年来,长江口表层沉积物总的潜在生态风险和单个污染物的潜在生态风险均呈现增加趋势。

Pollution of surface sediments and its assessment of potential ecological risk in the Yangtze Estuary

Through analyzing the contents of typical pollutants (PCB,Hg,Cd,Pb and As) in surface sediments of the Yangtze Estuary, with adopting pollution parameter techniques of single factor and Hakanson potential ecological risk index techniques,Based on the monitoring data of surface sediments in the Yangtze Estuary(Aug., 2004,),the quality status of these sediments were evaluated. The degree of potential ecological risks on these sediments ,the main factors of environment pollution and potential ecological risks in them ere determined quantitatively; The variation trends on the integrated potential ecological risks of these sediments and single potential ecological risks of every typical pollutants in them were analyzed. The results showed that the order of pollution extents of every typical pollutant was As>Pb>Hg>PCB>Cd. The average integrated index of all typical pollutants cd was 1.37,with rather good sediment quality in the Yangtze Estuary,the contents of every typical pollutant was less than reference values,As was main environment pollution factor;The surface sediments of the Yangtze Estuary only possessed rather light potential ecological risks,the sequence of potential ecological risk of different water area was North Shore of the Hangzhou Bay>South Branch of the Yangtze Estuary>North Branch of the Yangtze Estuary>Outside of the Yangtze Estuary;Every typical pollutant also possessed rather light potential ecological risks,the sequence of potential ecological risk of different typical pollutants was Hg>PCB>Cd>As>Pb,Hg was main factor of potential ecological risks in the Yangtze Estuary; The variation trends on the integrated potential ecological risks of these sediments and single potential ecological risks of every typical pollutants were increasing in recent years.