水动力作用对潮滩表层沉积物重金属时空分布的影响

Effect of water Dynamic Action on Spatial and Seasonal Distribution of Heavy Metals in Surface Sediments at Tidal Flat in Shanghai

选取上海滨岸潮滩具有代表性的4个采样断面,分析了重金属在潮滩表层沉积物中的季节性含量变化。结果表明,在水动力作用较弱的地貌部位,表层沉积物中重金属元素明显趋于富集。在崇明东旺沙、白龙港排污口附近和奉新边滩表层沉积物中,Cu、Pb、Fe、Mn、Zn的最低值出现于夏季,而在东海农场表层沉积物中,这几种重金属元素的最低值出现于秋季,夏季值反而较高,Cd与此不同。这说明在长江冲淡水作用下,重金属污染物能沿岸发生迁移与扩散,Cd受长江冲淡水影响较小。

Four sampling profiles were selected from Shang-hai coastal tidal flat. The concentrations of heavy metals in surface sediments of tidal flat have been seasonally analyzed.Results showed that at the geo-morphologic sections with weak water dynamic action, heavy metals were obviously enriched in the surface sediments accompanied by the deposit of fine partide silt.In the surface sediments of Dongwangsha at Chongming Island, Fengxin and the surface sediments nearby Bailonggang sewage discharging outlet, the lowest concentrations of Cu, Pb, Fe, Mn, Zn happened in summer.While in the surface sediments of Donghai Farm,the concentrations of those heavy metals reached the lowest in autumn and rose in summer. The sea-sonal change of Cd was different, which showed that heavy metals could transport and diffuse along the bank affected by Changjiang diluted runoff,while Cd was hardly influenced by it.