连环湖马圈泡沉积物重金属污染及潜在生态风险

Pollution and Potential Ecological Risk of Heavy Metals in Core Sediments from Majuan Lake in Lianhuan Lake, China

通过对连环湖马圈泡柱状沉积物重金属(Cr、Cu、Mn、Ni、Pb、Zn、Cd)等地球化学指标的分析,对马圈泡沉积物污染历史进行了讨论。根据元素的变化趋势,结合颗粒组成指标,采用相关分析,富集状况及潜在生态风险评价,并辅以210Pb、137Cs测年数据,研究了自1937年以来该湖区沉积物重金属元素污染特征、来源、污染历史及污染程度。结果表明,1987年以前各元素含量变化趋势平稳,1987年至今,7种重金属元素含量均明显增加。重金属元素的来源包括自然来源和人为输入。从单向污染系数来看Cu、Ni、Cr、Pb、Zn属于中等污染强度,Mn、Cd达到了强污染程度;从综合污染系数来看,表层重金属元素主要为中等程度的污染。沉积物重金属污染历史与该区经济发展阶段相吻合可为其湖区生态环境的整治与改善提供基础性的数据资料。

Sedimentation rates, element concentrations and grain size distributions of core sediments from Ma- juan Lake are investigated. According to ^210Pb and^ 137Cs dating, the pollution history of Majuan Lake is investi- gated based on the geochemical characteristics in core sediments. Our findings indicated that Cr, Cu, Mn, Ni, Pb, Zn and Cd are the main pollution heavy metals, which have different pollution history and pollution de- gree. The concentrations of heavy metals in sediments varied smoothly before1987. However, the concentra- tions of all elements increased obviously since 1987, which are mainly attributed the industries development. In recent years, Cu, Ni, Cr, Pb, and Zn in most sediment from upper profile showed moderate ecological risk level, but Mn and Cd showed strong ecological risk in the sediments. Similar results obtained from Eir and RI methods, while the heavy metal content increased rapidly since 1987 with the peak values appeared in the sur- face, which indicated the strongly potential risk. The history of elements pollution has strong link with the economy development in the catchment of Majuan Lake.