莱州湾滨海湿地沉积物重金属的空间分布

Spatial Distributions of Heavy Metals From the Laizhou Bay Littoral Wetland

通过研究莱州湾河口区滨海湿地沉积物重金属Pb,Zn,Cd,Cu的含量变化,分析表层沉积物及柱状沉积物,以期了解莱州湾河口区滨海湿地重金属含量的区域性变化,并从柱状沉积物剖面了解沉积物重金属累积的历史变化。研究结果表明,莱州湾河口区与邻近海域沉积物重金属含量在空间分布上与垂直分布上均呈现一定幅度的变化,且高浓度重金属显示区域内重金属呈现污染状况;在沉积物柱状剖面中,发现重金属含量在上层有大幅度增加之现象。另外,利用围隔式生态实验装置研究了该滨海湿地区域污染沉积物中重金属Pb,Zn,Cd,Cu在海水环境中的行为。结果表明,海水中的还原环境能抑制污染沉积物中重金属的释放,有助于体系中原有的重金属清除出水,而低生产力条件下,Pb,Zn表现出释放行为;高生产力和高悬浮物含量条件下,Pb和Zn表现出先释放后迁移,而Cd和Cu则呈现出相反的现象。

The contents of heavy metals Pb, Zn, Cd and Cu in the surface and core sediments from the Laizhou Bay esturine littoral wetland were analyzed to study the regional variations and accumulation history of sediment heavy metal contents in the study area. It is shown from the study results that the regional and vertical distributions of heavy metal contents show appreciable variations, the high heavey metal concentration areas have been polluted, and the heavy metal contents in the upper sediment increase greatly. In addition, the behaviours of heavy metals Pb, Zn, Cd and Cu in the polluted sediments from above littoral wetland in the seawater environment were studied by making mesocosm experiment. It is shown from the experiment results that the reduction envionment in seawater can inhibit the heavy metals in the polluted sediments from releasing to faciliate to remove the original heavy metals in ecosystem from seawater. Pb and Zn in low productivity conditions showed a release behaviour, and Pb and Zn in high productivity and high surspended matter concentration conditions showed a behaviour to release first and then to be transported, but the behaviour of Cd and Cu was opposite to that of Pb and Zn.