Study On Distribution Of Heavy Metal Pollution And Health Risk Assessment In Site

With the rapid development of Chinese economy,many cities are confronted with industrial reconstructuring.A large number of industrial discarded and abandoned sites are emerged due to the closure and move of many interprises with high industial pollution.These sites,which are high-pollution and high-risk areas of soil,will not only destroy the biological environment,but also be harmful to people’s health.It’s necessary to conduct environmental survey to contaminated site and health risk assessment in order to clarify the pollution situation of these sites.In this study,a contaminated site in a discarded smelter in Central China is choosen as the research site.This soil of this site is divided into 3 layers according to its various types and permeabilities.According to the distribution characteristics of interpolation of heavy metal pollutants,we conducted the health risk assessment in different layers of the research site.The main study results are as follows:Firstly,it is shown that the three layers are all polluted by As.The first layer is polluted most,mainly distributed in producing departments and its surrounding areas,northeast corner,slag area and north of roasting area.Secondly,it is presented that Cd,Pb and Zn only exist in the first and second layers,with the similar distribution areas of As.Their pollution scale decrease with the increase of depth,and the degree of pollution decreases rapidly with the increase of depth.According to distribution figures of pollutants risk by inverse distance interpolation method,it is shown that the carcinogenic risk and non-carcinogenic risk of As,Cd,and Pb in the first and second layers are all exceeded the limits,which are 10-6 and 1,and their risk distribution is similar with distribution of pollutant contents.In terms of contribution rate of exposure pathway,the carcinogenic risk of As mainly caused by intake by mouth,while the non-carcinogenic risk mainly caused by intake by mouth and inhalation of soil particulates.The carcinogenic risk and non-carcinogenic risk of Cd are mainly caused by inhalation of soil particulates,so it is suggested that the key attention should be paid to exposure pathway of intake by mouth during control and treatment.It is confirmed that the control values of risk of As,Pb and Cd are 8.19 mg/kg,633 mg/kg and 34.4 mg/kg,respectively.The results of contaminated site stratification survey and health risk assessment can provide site and pollutant characteristic parameters,instruct to screen remediation technology for contaminated soils,and provide reasonable advice on risk management control and remediation.