[Health Risk Assessment of Drinking Water Quality in Tianjin Based on GIS]

This study intends to assess the potential health hazards of drinking water quality and explore the application of geographic information system( GIS) in drinking water safety in Tianjin. Eight hundred and fifty water samples from 401 sampling points in Tianjin were measured according to the national drinking water standards. The risk assessment was conducted using the environmental health risk assessment model recommended by US EAP, and GIS was combined to explore the information visualization and risk factors simultaneously. The results showed that the health risks of carcinogens, non-carcinogens were 3.83 x 10⁻⁵, 5.62 x 10⁻⁹ and 3.83 x 10⁻⁵ for total health risk respectively. The rank of health risk was carcinogen > non-carcinogen. The rank of carcinogens health risk was urban > new area > rural area, chromium (VI) > cadmium > arsenic > trichlormethane > carbon tetrachloride. The rank of non-carcinogens health risk was rural area > new area > urban, fluoride > cyanide > lead > nitrate. The total health risk level of drinking water in Tianjin was lower than that of ICRP recommended level (5.0 x 10⁻⁵), while was between US EPA recommended level (1.0 x 10⁻⁴-1.0 x 10⁻⁶). It was at an acceptable level and would not cause obvious health hazards. The main health risks of drinking water came from carcinogens. More attentions should be paid to chromium (VI) for carcinogens and fluoride for non-carcinogens. GIS can accomplish information visualization of drinking water risk assessment and further explore of risk factors.