HUMAN HEALTH RISK ASSESSMENT FOR CHEMICAL POLLUTANTS IN DRINKING WATER SOURCE IN SHIZUISHAN CITY-NORTHWEST CHINA

Human health is closely related with the quality of drinking water. Various chemical pollutants in the drinking water can cause great risk to human health. Shizuishan city is an important coal-based industrial city where residents mainly rely on groundwater. In order to protect the safety of water supply, based on the sample survey, health risk assessment model recommended by the Unites States Environmental Protection Agency was adopted to assess the health risks of groundwater in the region. During the study, total 25 groundwater samples were colleted from drinking water supply wells and many parameters such as Cr6+, fluoride, arsenide, volatile phenol and cyanide were examined according to standard procedures recommended by Chinese Ministry of Water Resources. Evaluation results showed that the greatest risk value due to non-carcinogenic pollutants was caused by fluoride, while the greatest health risk due to chemical carcinogenic pollutants was primarily caused by Cr6+, the second was arsenide. The health risk due to chemical carcinogens was 3 magnitudes larger than that caused by non-carcinogenic pollutants, which indicated that chemical carcinogens were the primary pollutants in the drinking groundwater. The total health risk level was within the acceptable level proposed by Unites States Environmental Protection Agency, but exceeded the acceptable level recommended by International Commission on Radiologic Protection which meant that the groundwater needs pretreatment before consumption.