博尔塔拉河河水、表层底泥及河岸土壤重金属的污染和潜在危害评价

Pollution and Potential Ecology Risk Evaluation of Heavy Metals in River Water, Top Sediments on Bed and Soils Along Banks of Bortala River,Northwest China

以新疆博尔塔拉河为研究区,对河水、河床表层底泥及沿岸土壤中重金属Cr、Cu、Hg、As、Cd、Pb和Zn的来源、污染状况和潜在生态风险进行了研究.结果表明:1从总体看,博尔塔拉河水体中7种重金属的含量均较低,但Hg、Cd、Pb和Cr的最高值明显高于地表水环境质量Ⅱ类标准和WHO饮用水健康建议标准;表层底泥和沿岸土壤中重金属含量明显高于河水.2相关分析和富集系数计算表明,河水、表层底泥及沿岸土壤中重金属Hg、Cd、Pb和Cr均来自沿岸工业生产、城镇生活、交通运输及农业生产中污染物排放;重金属Cu、Zn和As主要来源于流域自然地质背景及成土母质因素.3污染评价表明3种介质中7种重金属的单因子污染指数值(Pi)和综合污染指数值(Pz)均小1,属于安全等级,清洁水平.4潜在生态风险评估表明博尔塔拉河表层底泥及沿岸土壤中7种重金属的单因子潜在生态风险(Eir)和综合潜在生态风险值(RI)均较低,未对水体及沿岸土壤环境造成危害.

This paper focuses on the sources,pollution status and potential ecology risks of heavy metals( Cr,Cu,Hg,As,Cd,Pb,and Zn) in the surface water,top sediment of river bed and soil along banks of Bortala River,which locates in the oasis region of Xinjiang,northwest China.Results showed that: 1 As a whole,contents of 7 tested heavy metals of Bortala River were low,while the maximum values of Hg,Cd,Pb,and Cr in the river water were significantly higher than those of Secondary Category of the Surface Water Quality Standards of People’s Republic of China( GB 3838-2002) and Drinking Water Guideline from WHO.Analysis showed that the heavy metals contents of top sediment on river bed and soils along river banks were significantly higher than those of the river water.2Correlation analysis and enrichment factor( EF) calculation showed that in the river water,top sediment on river bed and soils along river banks,Hg,Cd,Pb,and Cr mainly originated from industrial emissions,urban and rural anthropogenic activities,transportation and agricultural production activities; While Cu,Zn,and As mainly originated from natural geological background and soil parent materials.3 Pollution assessment showed that in three matrices,the single factor pollution index( Pi) and the integrated pollution index( Pz) of 7 heavy metals were all lower than 1,and they all belonged to safe and clean levels.4Potential ecology risk evaluation showed that as a whole the single factor potential ecological risk( Eir) and the integrated potential ecology risks( RI) of 7heavy metals were relatively low,and would not cause threats to the health of water and soil environment of river basin,while the potential ecology risks of Cd,Hg,Pb,and Cr were significantly higher than those of other heavy metals.