Health-based Risk Assessment Of Contaminated Sites

Contaminated sites, one important kind of environmental contamination sources, include mines, factories, gas stations, underground oil tanks, landfills, waste piles and so on. Discharge and leakage of pollutants will contaminate soil, water and air, and do harm to the ecosystem and human health. With the establishment of the policies of 'people-oriented' and 'harmonious development of economy, society and environment', treatment of contaminated sites will be gradually conducted, and health-based risk assessment of contaminated sites, which is the basis of decision-making of pollution treatment, will be in great consideration.Based on the route and mechanism of ingestion of contaminants and dose-response relationship, the health risk assessment approach of contaminated sites was discussed and index system of risk assessment was established. Furthermore, this paper assessed the health risk caused by leakage of organic cleaner in a factory in North China.1. The method of calculating pollutant intake and health risk based on lifestage were proposed.2. The concepts and the estimation approaches of 'Superposed Risk' and 'Total Multi-pathway Exposure Risk for the Same Substance' were put forward.3. The formula of intake of oral exposure was modified.4. The index system of health risk assessment was developed, which involved indices and standards of health risk assessment, physiological indices and indices related to chemical properties.5. The paper assessed the carcinogen and non-carcinogen risk of the workers inside the factory through inhalation and dermal contact, and of residents living downgradient of the factory who drink contaminated groundwater. The assessment indicated that the non-carcinogen risk of the two populations be negligible with Total exposure Hazard Index being 0.0214 and 0.174 which are much less than unity, and the carcinogen risk be great with Total exposure Cancer Risk being 1.32×10^-5 and 1.62×10^-6 which are 13.2 and 1.62 multiples of the lowest risk acceptable level. The Total Pathway Cancer Risk of inhalation, dermal contacting polluted air and contaminated soil for the workers are 9.38×10^-6, 2.8×10^-6 and 1.01×10^-6. The main carcinogen factors are carbon tetrachloride, trichloromethane, trichloroethylene and tetrachloroethylene.6. The measure of contamination protection and treatment were proposed and treatment levels of the contaminated soil were developed.