河口泥沙再悬浮对悬沙中重金属元素的影响

STUDY OF HEAVY METALS INFLUENCED BY SEDIMENT RESUSPENSION IN THE CHANGJ ING ESTUARY

基于1997年3月9日和7月27日长江口南槽定点连续观测资料,分析了河口泥沙再悬浮对重金属元素的影响。研究结果表明,在长江口南槽,近底悬沙浓度和悬沙中重金属含量均随时间变化而变化,且两者具有良好的对应关系;因子分析结果显示对所有金属元素都占绝对优势的F1因子为泥沙再悬浮,泥沙再悬浮现象对本次观测中近底泥沙中重金属含量变化起主导作用。泥沙再悬浮一方面会导致悬沙和床沙的混合,另一方面有可能导致重金属从泥沙中向水体中再释放,在长江口南槽,枯季近底悬沙中重金属含量的变化主要缘于悬沙、床沙的混合;而洪季除悬沙和床沙混合之外,还存在泥沙再悬浮过程泥沙中重金属的释放,这可能与洪季高水温、低溶氧等环境因素以及强烈的水动力条件有关。

Based on data observed in the South Passage in of the Changjiang Estuary March and July1997,the variance of particulate heavy metal concentration during sediment resuspension was studied.Particulate heavy metal concentrations change with the variance of suspended sediment concentrations near bed.The variance of near bed particulate heavy metal concentrations in dry season is mainly influenced by the mixture between sus-pended sediment and bed load during sediment resuspension,while the variance in flood season is not only in-fluenced by the mixture but also by the release of heavy metals from suspended sediment.All those may at-tribute to different water environment and hydrodynamic condition in two seasons.