自贡市城市河流沉积物重金属分布及潜在生态风险评价

Distribution and Potential Ecological Risk Assessment of Heavy Metals in River Sediments of Zigong

对自贡市河流表层沉积物中Cd、Hg、As、Pb、Ni、Cu、Cr和Zn 8种重金属含量及来源进行了分析,并对其潜在生态风险进行评价。结果表明,各重金属含量平均值除Cr外均超过全国土壤背景值;重金属来源主要为交通行业污染,且主要集中在威远河;8种重金属潜在生态风险大小为:Cd﹥Hg﹥As﹥Cu﹥Pb﹥Ni﹥Zn﹥Cr,且各元素的风险指数均值都属于轻微潜在生态风险;仅1个样点为中等综合潜在生态风险,其余样点为轻微综合潜在生态风险。

The concentrations and the sources of eight heavy metals including Cd,Hg,As,Pb,Ni,Cu,Cr and Zn in Xushui River,Weiyuan River and Fuxi River of Zigong were systematically analyzed.And the potential ecological risk of heavy metals was evaluated by method of potential ecological risk index.The results showed that the average content of heavy metals except for Cr were higher than those of the national soil background value,the main sources of heavy metals were traffic pollution,and the pollution was mainly concentrated in Weiyuan River.The potential ecological risk of eight heavy metals in sediments were in the following order:Cd>Hg>As>Cu>Pb>Ni>Zn>Cr,and the average risk index of each element belonged to slight potential ecological risk,only one of the sampling sites was medium potential ecological risk,and the remaining sample points were slight potential ecological risks.