Health Risk Assessment And Management Of Heavy Metal Pollution

In recent years, heavy metal pollution accidents have occurred frequently in many regions of China, and the public has become increasingly concerned about its health. Heavy metal pollution has become a big challenge for China. To improve the heavy metal pollution treatment and manage health risk from the source, it is necessary to conduct human health risk analysis and put risk alleviation measures into place accordingly.Through the analysis of typical heavy metal pollution accidents and the technical demand of health risk assessment and management of China, this study designed a "4M3R" pattern. This pattern, which generalizes the characteristics of heavy metal risk, multi-sources, multi-expoure routes and mulit-receptors, consists of risk assessment, risk perception analysis and risk management.A case study was conducted in a lead and zinc mining area in east China. Drinking water, indoor air, outdoor air, soil and food were sampled from three nearby villages of the mining area.13heavy metals were detected, including Ag, As, Be, Cd, Cr, Cu, Ni, Hg, Pb, Sb, Se, Tl and Zn. The detection results indicate that the drinking water is safe. Air pollution is most serious in the closest village to the mine, and indoor air quality is poorer thant that of outdoor air. The soil quality is quite serious in the mining area, specially for As, Cd, Cu, Pb and Zn.Exposure investigation was conduced to obtain the indigenous population parameter, dietary parameter, activity parameter, water-related activity parameter and exposure parameter. Exposure doses from water ingestion, water dermal contact, soil ingestion, soil dermal contact, inhalation and food ingetion were estimatated. Furthermore, carcinogenic risks and non-carcinogenic risks posed by heavy metal pollution were assessed. The results show that the carcinogenic risk of local people is as high as10"2, and exceeds the general risk acceptable level. Inhaltion route contributes more than99%to the total risk. As is the main risk soure and responsible for more than99%. As to non-carcinogenic risk, As accouts for87%of the total hazard quotient. The hazard quotients of Pb, Cd, Be, Sb and Hg are all exceed the criterion value, indicating that the potiental health hazard is evident. Morever, young individuals are more susceptible to the toxic effects of Pb,65%children of A village have a blood lead concention exceeding the WHO lead poisoning diagnosis criteria. Air, soil and food were the main exposure pathways for child lead exposure.The risk perception research results show that most local people regard heavy metal pollution as a usual, terrible, chronic, fatal, profitless, unkown and unevadable risk. Most residents consider the pollution is caused by the nonfeasance of the mining factory, and they can not accept current risk situation, but they firmly support the possible future polluton control and risk management activities. The people of thress villages have diffent risk acceptable level. Residents of A village have the easiest acceptable attitude to the heavy metal pollution, and the95percentile risk acceptable level is3*10-7.Risk estimation and public risk acceptable level relects that the current health risk can not be accepted, and risk alleviation measures must be taken. Based on environmental monitoring and risk estimation, As, Pb, Be, Cd, Sb, Hg and Zn were selected as priority pollutants in this mining area. Through risk comparation, high-risk population, like children in A village, were identified for risk management. In addition, keystone of risk control and the according risk alleviation measures were proposed in terms of pollution prevention, exposure routes cut, risk receptor protection and risk communication.