白马湖底泥重金属污染特征分析

Analysis of Heavy Metal Pollution Characteristics about Bottom Sediment in Baima Lake

[目的]对白马湖区底泥重金属污染状况进行监测与评价。[方法]对白马湖6个采样点位、24个底泥样品中Cu、Zn、Pb、Cd 4种重金属含量进行测定,分析底泥表层和剖面重金属的含量及分布特征。在此基础上,应用地积累指数法进行污染等级评价。[结果]所有底泥样品中4种重金属含量值均低于土壤环境质量标准中的三级标准。在空间分布上,总体呈现出"湖区含量>入湖口含量>出湖口含量"的规律,且随深度增加重金属含量递减。Cu、Zn和Pb含量一般在0.4 m深度附近开始达到或趋近土壤背景值。相关性分析及污染评价结果表明,Cu、Zn和Pb处于由无污染向中等污染过渡阶段,而Cd的含量在部分测点已达到中等污染水平,并呈现明显的内源污染特征。[结论]该研究可为白马湖生态修复与保护提供科学依据。

[Objective] The research aimed to monitor and evaluate the heavy metal pollution status about bottom sediment in Baima Lake.[Method] Based on 6 water samples and 24 sediment samples from Baima Lake,four kinds of heavy metal concentration of Cu,Zn,Pb and Cd were measured.The content and distribution characteristics of heavy metal in the surface layer and profile of the bottom sediment were analyzed.By using the index of geoaccumulation,the classes of pollution were evaluated.[Result] The results showed that 4 kinds of heavy metal content in all samples of bottom sediment didn＇ t surpass the Ⅲ level standard.In space distribution,heavy metal contents descended from Lake District to estuary to the bayou.With the increase of depth,heavy metal contents decreased.The contents of Cu,Zn and Pb arrived at or approached to the background value of soil about 0.4 m under the water surface.Correlation analysis and pollution assessment indicated that Cu,Zn and Pb were at the transitory stage from non-pollution to medium pollution.However,Cd had partially reached to medium pollution level.It presented obvious characterstics of endogenous pollution.[Conclusion] This research could provide theoretical basis for the ecological remediation and protection of Baima Lake.