Arsenic risk assessment of geothermal water in Tangchi, China

On the basis of health risk assessment methods of contaminated sites recommended by the US Environmental Protection Agency, human health risks due to arsenic in the geothermal water of Yunnan Tangchi have been evaluated by combining the speciation of arsenic. The results have shown that the total arsenic level in the geothermal water is 0.1655mg L-1, in which As3+ and As5+ account for 64% and 36% respectively. The arsenic total non-carcinogenic risk index is 75.73; total carcinogenic risk is 1.10×10-2, which can lead to strong non-carcinogenic and carcinogenic hazards to human health. Drinking is the most important route of exposure to risk, which accounts for more than 90% of the hazards. The health risk of As3+ approximately is 107 times that of As5+, accounting for 99.1% of the total risk. The speciation has greatly affected the health risks of arsenic. There are some uncertainties in the calculated result in this study, but it can be used for reference in the study of the health risk assessment consisting of the speciation of pollutants. © 2012 WIT Press.