渭河下游渭南段水体重金属(含类金属)分布与水环境质量评价

Distribution of heavy metals(including metalloids)in Weinan section of the lower Weihe River and assessment of water environment quality

在渭河下游渭南段分别选取树园水库、拾村水库、沋河水库、三河交汇口4个断面,于2019年1—9月每月采样1次,测定水体中Cu、Zn、Pb、Cd、Cr6+、Hg、As 7种重金属(含类金属)的含量,分析其分布特征与污染现状,同时根据树园水库监测断面的水环境质量监测数据,引入基于熵权的水环境质量模糊物元评价模型,对研究区域的水环境质量进行综合评价。结果表明,Cu、Pb、Cd、Cr6+、Hg、As含量均达到地表水环境质量Ⅰ类标准,Zn含量符合地表水环境质量Ⅱ类标准,Pb是主要的潜在生态风险因子,渭河下游水质总体良好,主要污染指标为溶解氧、化学需氧量、高锰酸盐指数和总氮。

Four sections were selected in the Weinan section of the lower reaches of the Weihe River,including Shuyuan Reservoir,Shicun Reservoir,Zhuhe Reservoir,and the intersection of the three rivers,samples would be taken once a month from January to September 2019 to determine the content of 7 heavy metals(including metalloids)in water,including Cu,Zn,Pb,Cd,Cr6+,Hg and As,and their distribution characteristics and pollution status were analyzed.At the same time,based on the water environment quality monitoring data of the Shuyuan Reservoir monitoring section,a fuzzy matter-element evaluation model for water environment quality based on entropy weight was introduced to comprehensively evaluate the water environment quality of the study area.The results showed that the contents of Cu,Pb,Cd,Cr6+,Hg and As met the ClassⅠstandard for surface water environmental quality,and the content of Zn met the ClassⅡstandard for surface water environmental quality.Pb was the main potential ecological risk factor.The water quality of the lower reaches of the Weihe River was generally good,and the main pollution indicators were dissolved oxygen,chemical oxygen demand,permanganate index and total nitrogen.