Health Risk Assessment of Arsenic in Geothermal Water at Tangchi Town,Yunnan Province

Based on the evaluation method for health risk assessment of contaminated sites recommended by U.S.Environmental Protection Agency,in combination with the arsenic speciation for the first time,the health risk of geothermal water arsenic pollution at Tangchi Town,China was evaluated.Results showed that total arsenic concentration in geothermal water was 0.165 5 mg/L,with As3 + and As5 + proportions approximately 64% and 36% respectively.Arsenic could produce strong non-carcinogenic and carcinogenic hazards to human health,with non-carcinogenic index of 75.73 and carcinogenic index of 1.10 × 10-2.The main exposure way was the drinking water,which accounted for more than 90%.Health risk caused by As3 + was about 107 times more than As5 +,accounting for 99.1% of the total risk.Arsenic speciation greatly impacted health risk associated with arsenic exposure.Although the results had some uncertainties,they were important for incorporating contamination speciation into health risk assessment.