文章摘要
徐梦,刘鸿雁,罗凯,崔俊丽,刘艳萍,李家飞.夜郎湖表层沉积物重金属分布特征及生态风险评估[J].农业环境科学学报,2017,36(6):1202-1209.
夜郎湖表层沉积物重金属分布特征及生态风险评估
Distribution and ecological risk assessment of heavy metals in surface sediments of Yelang Lake
投稿时间:2016-09-12  
DOI:10.11654/jaes.2016-1179
中文关键词: 沉积物  重金属  分布  形态  风险评价  夜郎湖
英文关键词: sediment  heavy metals  distribution  speciation  risk assessment  Yelang Lake
基金项目:国家自然科学基金(41461097);国家自然科学基金委员会-贵州省人民政府喀斯特科学研究中心项目(U1612442);贵州省科技计划项目(黔科合J重大字[2015]2001);贵州省教育厅重点实验室项目(黔教合KY字[2016]001);研究生创新实践基地建设项目(贵大研SJJD[2015]004)
作者单位E-mail
徐梦 贵州大学资源与环境工程学院, 贵阳 550025  
刘鸿雁 贵州大学资源与环境工程学院, 贵阳 550025
贵州大学农学院, 贵阳 550025 
hongyan.l@163.com 
罗凯 贵州大学资源与环境工程学院, 贵阳 550025  
崔俊丽 贵州大学资源与环境工程学院, 贵阳 550025  
刘艳萍 贵州大学资源与环境工程学院, 贵阳 550025  
李家飞 贵州大学资源与环境工程学院, 贵阳 550025  
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中文摘要:
      为研究喀斯特地质背景下重金属在河流沉积物中积累和释放过程以及重金属污染的环境生态风险,以贵州省普定县夜郎湖表层沉积物为研究对象,分析其中Zn、As、Cd、Cr、Ni、Cu和Pb的含量及形态分布特征,采用地累积指数法和潜在生态危害指数法对各重金属的污染水平及潜在生态风险进行评价。结果表明:夜郎湖表层沉积物中Zn、Pb、Cr、Ni、Cu、As和Cd的平均含量分别为141.75、83.76、54.97、38.60、36.61、9.47、1.50 mg·kg-1,除As和Cr外,其他重金属含量明显高于贵州省沉积物地球化学背景值;Cr、Ni、Cu和As以残渣态为主,所占比例分别为52.56%~80.21%、30.09%~70.43%、38.05%~80.77%和70.04%~94.89%,Pb、Zn易还原态比例相对较高,Cd的酸可交换态占10.93%~49.15%,易还原态占25.58%~62.49%,表现出很强的生物活性。从沉积物的空间分布来看,重金属活性高的地方绝对含量也高,且Cu与其他重金属含量均呈极显着相关关系,说明沉积物中重金属来源与网箱养鱼有很大关系。地累积指数法结果表明,该区域受Pb和Cd污染较为严重,部分可达到中度污染水平;潜在生态风险评估结果表明,Cd是最主要的生态风险因子,沉积物中Cd在地球化学高背景下,可能受到网箱养鱼废弃物沉积的影响。研究区基本处于轻度到中度潜在生态危害水平,喀斯特地区重金属Cd的地球化学高背景与污染叠加对水生生态系统具有潜在环境风险。
英文摘要:
      Carbonate rock, which is typical heavy metals geochemical anomaly karst terrain, accounts for 73% of the land area in Guizhou Province. The geochemical background value of Cd is 0.31×10-6, which is 2.5~3.5 times higher than the abundance value. Therefore, the accumulation, release, and environmental risks of heavy metals should be studied in this region. To evaluate pollution levels comprehensively, the concentration and speciation distributions of seven heavy metals(Zn, As, Cd, Cr, Ni, Cu, and Pb) were analyzed in surface sediments from Yelang Lake. The geoaccumulation index(Igeo) and the potential ecological risk index(RI) were used to assess the potential contamination and the environmental risks associated with heavy metals. The results showed that the mean contents of Zn, Pb, Cr, Ni, Cu, As, and Cd in the surface sediments were 141.75, 83.76, 54.97, 38.60, 36.61, 9.47, and 1.50 mg·kg-1, respectively. These contents, excluding As and Cr, were higher than the geochemical background values of supergene sediments in Guizhou Province. Cr, Ni, Cu, and As in the sediments were dominated mainly by the residual fraction, which accounted for 52.56%~80.21%, 30.09%~70.43%, 38.05%~80.77%, and 70.04%~94.89%, respectively. The reducible fractions of Pb and Zn were higher than they were for the other metals, and the percentages of the exchangeable and reducible fractions of Cd were 10.93%~49.15% and 25.58%~62.49%, respectively. The Igeo showed that there were more serious degrees of Pb and Cd contamination in Yelang Lake. The RI showed that Cd is the main ecological risk factor, which was affected by sediment from the fish culture in net pen, and the pollution degree of heavy metals in the surface sediments from Yelang Lake represented light to moderate ecological harm. Therefore, Cd geochemical background levels in karst areas are a high potential environmental risk for aquatic areas.
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