Health Risk Assessment Systemon Remediation Of Contaminant In Soil And Groundwater

Practice in western developed countries for many years shows that, it is usually unsuccessful to remediate contaminat in soil and groundwater based on environment standard. To solve this problem more smoothly, risk conception and health risk assessment are introduced into traditional remediation of subsurface contamination, and several remediation modes based on health risk have been developed.Among many risk sub-modes, RBCA mode developed by American Society for Testing and Materials is most successful and famous. So RBCA mode is adopted in this paper to frame health risk analysis theory system on remediation of contaminat in soil and groundwater. This theory system includes many mathematical models: health risk assessment, contaminant transporting and fating in environment, calculation of remediation and monitoring target based on health risk, judgement and analysis of NAPL. These models not only come from ASTM E2081-00 which defines RBCA mode, but also absorb latest achievement in this domain. In order to make theory guide practice better, a software toolkit have been developed based on the theory system.A health assessment of carbon tetrachloride in a water-bearing basin has been executed by Using the developed software toolkit. This water-bearing basin is a main source of water supply in one north city in China . However, karst water in the basin has been contaminated with carbon tetrachloride, which roots in a pesticide plant located at hill slope in recharge area of karst aquifer. Carbon tetrachloride in groundwater hazards human health through drinking groundwater, volatilization into indoor air and outdoor air. The health risk caused by these three exposure pathway has been assessed to thirteen serious contaminated wells. The results show that, drinking groundwater is the critical exposure pathway, and the risk caused by volatilization into indoor air also exceeds the target health risk limit. The health risk caused by volatilization into ambient air from probable leakage point of carbon tetrachloride within pesticide plant has also been assessed. The results show that, the possible maximum impact distance is 1280 meters. Moreover, a risk map has been...