梁子湖水体和底泥中微量元素及重金属的空间分布格局及污染评价

ASSESSMENT AND SPATIAL PATTERNS OF TRACE ELEMENTS AND HEAVY METALS FROM WATER BODY AND SEDIMENTS IN THE LIANGZI LAKE

利用多元统计方法研究了湖北梁子湖水体及底泥中12种微量元素和重金属(As,Ba,Co,Cr,Cu,Hg,Mn,Ni,Pb,Sb,Sr和Zn)的含量及空间格局,并通过饮用水及地表水质量标准及地质累积指数评价梁子湖水质及底泥状况。结果表明:梁子湖的水体质量较好,仅Cu是潜在污染物质;对湖泊底质而言,As是主要污染物质,Cu、Pb和Zn处在轻微的污染状态。空间格局显示:受人类活动的影响,湖泊水体中的重金属分布有较强的区域性,最大值出现在人类活动相对集中的梁子岛附近;在湖泊底泥中由于地质背景一致性而差别不大。相关分析表明,较之湖泊水体,湖泊底泥中的重金属元素的关系更密切,强相关性说明它们可能有共同的来源。未来研究应结合湖泊中大型水生植物及鱼类的重金属含量更全面考虑生态学效应,为恢复湖泊生态环境的管理提供重要参考。

Anthropogenic activities,particularly mining and smelting,have been elevating the concentrations of trace elements and heavy metals in the fluvial system including rivers and lakes,which give hazards to human and wildlife.For this study,water and sediment were sampled in 2005 from the Lake Liangzi,consequently about 12 trace elements and heavy metals(i.e.,As,Ba,Co,Cr,Cu,Hg,Mn,Ni,Pb,Sb,Sr and Zn) were determined by an Inductively Coupled Plasma Atomic Emission Spectrometer(ICP-AES) for their spatial variations using multivariate statistic techniques and quality assessment.Trace metals in the waters were compared with the national and international standards for drinking water,while trace metals in the sediment were assessed using geo-accumulation index.The results indicated that Cu was the potential pollutant in the water,while in terms of sediment,Cu,Pb,Zn and particularly As was the major pollutant.Cluster and correlation analyses demonstrated trace metals in the sediment showed more strong correlations,indicating their common sources.Spatial patterns of trace metal concentrations in the water could better reflect the spatial sampling location than sediment,indicating that waters were more susceptible to human disturbances,i.e.the maximum concentrations occurred in the sites close to Island Liangzi,an area with intense human activities.Further research into the subject will also include hydrophyte and vertebrates(i.e.fish) and help develop water quality management with the aim to restore shallow lakes in the Yangtze River.