宁夏太阳山湿地水环境重金属分布特征及污染评价

Distribution Characteristics and Pollution Evaluation of Heavy Metals in Water Environment of Taiyangshan Wetland in Ningxia

为了解宁夏太阳山湿地水环境重金属的污染状况,于2019年冬季、春季、夏季、秋季对水体和表层沉积物中As、Cd、Hg、Pb、Cr、Cu、Mn、Zn这8种重金属的含量进行了监测,应用多元统计方法分析水环境重金属的时空异质性,采用内梅罗综合污染指数法、地累积指数法评估水环境重金属的污染状况。结果表明:总体上水体重金属含量不高,只有Hg含量超过GB 3838—2002《地表水环境质量标准》中的Ⅲ类水标准;表层沉积物受重金属污染严重,只有Cr含量未超过宁夏土壤背景值。水体和沉积物重金属含量东湖区较高,南湖区较低。内梅罗综合污染指数法评估结果表明,全水域水体重金属污染水平较低,其中西湖区污染最严重,四季中冬季污染最为严重,对污染贡献最大的是Hg。地累积指数法评估结果表明,表层沉积物受Hg污染最为严重,其中冬季污染最严重。

The concentrations of As,Cd,Hg,Pb,Cr,Cu,Mn and Zn in water bodies and surface sediments were monitored to explore the pollution condition of heavy metals in the water environment of Taiyangshan National Wetland Park in Ningxia in winter,spring,summer and autumn of 2019.Multivariate statistical methods were used to analyze the temporal and spatial heterogeneity of heavy metals in the water environment,and Nemerow Comprehensive Pollution Index Method and Geo-accumulation Index Method were used to assess the pollution status of heavy metals in the water environment.The results show that the heavy metal contents of the waterbody were generally at low level and only the Hg content exceeded theⅢclass surface water standard of the"Environmental Quality Standard for Surface Water(GB 3838-2002)".The surface sediments were seriously polluted by heavy metals except for Cr,which did not exceed the soil background value of Ningxia.The contents of heavy metals in water and sediments were higher in the east part of the lake and lower in the south part of the lake.The heavy metal pollution level of the waterbody as a whole was low by usinig Nemerow Comprehensive Pollution Index Method.While the most serious pollution was found in the west part of the lake and in winter.Among the heavy metals,Hg contributed the most to the pollution.By using the Geo-accumulation Index Method,it was found that the surface sediment was most seriously polluted in winter and Hg contributed the most to the pollution.