Arsenic exposure from drinking water and staple food (rice): A field scale study in rural Bengal for assessment of human health risk

Arsenic is a well-known carcinogen with emerging reports showing a range of health outcomes even for low to moderate levels of exposure. This study deals with arsenic exposure and associated increased lifetime cancer risk for populations in arsenic-endemic regions of rural Bengal, where arsenic-safe drinking water is being supplied at present. We found a median total exposure of inorganic arsenic to be 2. 9 mu g/Kg BW/day (5th and 95th percentiles were 1.1 mu g/Kg BW/day and 7.9 mu g/Kg BW/day); with major contribution from cooked rice intake (2.4 mu g/Kg BW/day). A significant number of households drank arsenic safe water but used arsenic-rich water for rice cooking. As a result, 67% participants had inorganic arsenic intake above the JEFCA threshold value of 3 mu g/Kg BW/day for cancer risk from only rice consumption when arsenic contaminated water was used for cooking (median: 3.5 mu g/Kg BW/day) compared to 29% participants that relied on arsenic-free cooking water (median: 1.0 mu g/kg BW/day). Arsenic in urine samples of study participants ranged from 31.7 to 520 mu g/L and was significantly associated with the arsenic intake (r = 0.76); confirming the preponderance of arsenic exposure from cooked rice. The median arsenic attributable cancer risks from drinking water and cooked rice were estimated to be 2.4 x 10(-5) and 2.7 x 10(-4) respectively, which further emphasized the importance of arsenic exposure from staple diet. Our results show that any mitigation strategy should include both drinking water and local staple foods in order to minimize the potential health risks of arsenic exposure.