基于多评估法的硫铁矿区土壤重金属污染特征及源分析

Characteristics and Source Analysis of Heavy Metal Pollution in Soil of Pyrite Mining Area Based on Multi-Assessment Method

以川南某硫铁矿采选矿区及其尾矿渣场周边农用地为研究对象,采集并测定了51个表层土壤样品、4个背景点土壤样品和4个剖面土壤样品的Cd、Cr、Hg、Ni、Pb、As、Cu、Zn含量,分析其空间分布特征,应用内梅罗综合污染指数法剖析土壤重金属污染现状,并结合相关性分析和正定矩阵因子分析法对土壤重金属来源进行解析。结果表明:研究区土壤Cd、Cr、Hg、Ni、Pb、As、Cu、Zn含量均值分别为2.2、163.0、0.2、66.6、41.8、15.1、80.8、153.0 mg/kg,其中Cd、Cr、Ni、Cu存在不同程度的累积现象,且多个重金属元素之间存在显著相关性;Cd为主要污染元素,Cu具有较强的垂向迁移能力;土壤重金属主要来源为工矿活动源(39.5%)、自然源(37.6%)、大气沉降与交通混合源(22.9%)。川南某硫铁矿周边农用地存在多重金属元素复合污染,其中工矿活动起主导作用。

The contents of Cd,Cr,Hg,Ni,Pb,As,Cu and Zn in 51 surface soil samples,4 background site soil samples and 4 profile soil samples were collected and determined by taking the agricultural land around a pyrite mining area and its tailings site in southern Sichuan as the research object.The spatial distribution characteristics of all samples were analyzed.The present situation of soil heavy metal pollution was evaluated by Nemero comprehensive pollution index method,and the source of soil heavy metals was analyzed by correlation analysis and positive definite matrix factor analysis.The results show that the mean values of Cd,Cr,Hg,Ni,Pb,As,Cu and Zn in the study area are 2.2,163.0,0.2,66.6,41.8,15.1,80.8 and 153.0 mg kg,respectively.Among them,Cd,Cr,Ni and Cu have different degrees of accumulation,and there is a significant correlation among many heavy metal elements;Cd is the main pollution element,and Cu has strong vertical migration ability.The main sources of heavy metals in soil are industrial and mineral activity sources(39.5%),natural sources(37.6%)and mixed sources of atmosphere and traffic(22.9%).There is multiple metal element compound pollution in agricultural land around a pyrite mining area in southern Sichuan,in which industrial and mineral activities play a leading role.