LONG-TERM HEAVY METALS POLLUTION AND HEALTH RISK ASSESSMENT IN THE HAIHE RIVER, CHINA

Water samples collected from the Haihe River in China between 2001 and 2010 were analyzed for heavy metals and their health risk. Five heavy metals (As, Cr, Cu, Hg, and Pb) were determined in the water. The temporal variations in five metals concentrations generally decreased from 2001 to 2010. The concentrations of Cr, As, and Pb were similar in different sampling sites, while Hg and Cu exhibited the high concentrations in the downstream river next to the estuary. Results of principal component analysis (PCA) showed that Cr and Pb were derived from rock-derived and industrial wastewater, while As, Hg, and Cu was atmospheric deposition and industrial sewage originated. The health risks caused by metals in water were assessed by model recommended by the US Environmental Protection Agency. The health risk showed both the non-carcinogenic and carcinogenic risks were decreased from 2000 to 2010 as a consequence of the concentrations of heavy metals decreased in Haihe River. However, the non-carcinogenic risk exceeded 1 and carcinogenic risk were more than 1x10(-5) in each years, indicating that there were non-carcinogenic and carcinogenic risks in water from Haihe River. Arsenic was the most important contributor to both non-carcinogenic and carcinogenic risks in the present study. In particular, both Cr and As all exhibited a carcinogenic risk above the acceptable or tolerable risk level in each years, indicating that long term exposure to such water can lead to cancer. Therefore, it is very important to control coal combustion and industrial sewage discharge for removing Cr and As in the water to minimize risks.