Research On Refined Probabilistic Health Risk Assessment Based On Microenvironment

Objective:This study divides the microenvironment according to the exposure scenario,aiming to construct a refined exposure conceptual model.Taking a smelter in Shaoguan,China as an example,the pollution risk assessment and health risk assessment of trace metal pollutants（TMs）in the plant and surrounding soil were carried out.The soil in the factory and its surrounding areas was divided into microenvironments according to the activities of exposed people,and the health risk characteristics of different microenvironments to exposed people were analyzed,which provided scientific basis for decision-making departments to formulate site soil remediation strategies and assessment,classification and management of environmental health risks.Methods:In this study,the geo accumulation index and pollution index were used to analyze the degree of soil heavy metal pollution.The potential ecological risk index was used to evaluate the soil ecological risk.The questionnaire was used to investigate the fine exposure parameters of the surrounding population.The Monte Carlo simulation method was used to evaluate the probabilistic health risk of trace metals in soil.All statistical analysis was performed using SPSS v26.0,ArcGIS 10.2 was used to draw map sampling points,Crystal Ball v11.1.24 software was used for Monte Carlo simulation,and the risk assessment results were plotted using Origin Pro 9.0.Results:1.Cu,Zn,As,Ag,Cd,Sn,Sb,Tl,Pb and Hg exceeded the background value of Guangdong soil.2.（1）The results of geo-accumulation index evaluation showed that the pollution of Ag in the samples was slightly polluted,the samples polluted by Zn,Sb and Hg showed moderate pollution,the samples polluted by Pb showed severe pollution,and As and Cd had reached the category of severe pollution.（2）Zn,Ag,Cd,Pb and Hg were selected as characteristic pollutants by single factor index method.（3）Hg,Sb,Pb and Cd have strong potential ecological risks.3.The results of concentration-oriented deterministic risk assessment showed that Co,Cd,Sb,Mn,As,Pb and Hg required probabilistic risk assessment to determine the possibility of residents being exposed to risks,and the health risks of 95%quantile concentrations of other TMs were within the threshold range.4.（1）The results of microenvironment-oriented probabilistic risk assessment showed that the carcinogenic and non-carcinogenic risks of residential microenvironment were the highest(2.84×10^-5～6.7×10^-5,1.59～5.57).The probability of carcinogenic risk greater than 10^-6 in adults and children was more than95%,and the probability of non-carcinogenic risk greater than 1 was 68.2%and 91.8%,respectively.（2）The average health risk of adults was in the order of residential area>factory>park>traffic trunk,and that of children was residential area>traffic trunk>park.（3）The health risks of As,Pb and Mn were the highest in each microenvironment,and the health risk of children was greater than that of adults.（4）There are differences between the results of the two risk assessment methods.5.The results of sensitivity analysis showed that exposure time and exposure cycle ED were the most important parameters affecting the results of health risk assessment,followed by children’s weight and TM concentration.Conclusion:1.Children in the study area are easy to contact with soil outdoors,so it is recommended to keep their hands clean and avoid"hand eating"behavior;2.Probabilistic health risk assessment method can more accurately describe the risk distribution,and can achieve accurate risk control and repair measures for the study area;3.Exposure time（ET）and exposure period（ED）are the most important parameters affecting the results of health risk assessment.