ASSESSMENT OF ARSENIC EXPOSURE RISKS FROM DRINKING WATER AND DIETARY COMPONENTS IN RURAL BENGAL

Local governments and various national and international aid agencies are now trying to decrease the extent of arsenic (As) exposure from drinking water by supplying safe water to communities of the As affected regions of West Bengal and Bangladesh. However increasingly, the local staple diet is being implicated as an alternative important route of As exposure in these regions. This study assesses the potentiality of inorganic As exposure through consumption of staple diet (mainly rice with vegetables), particularly when people are drinking As safe water, by combining quantification of As accumulation in different food stuffs and drinking water with questionnaire survey. The results indicate that the regular diet of rural villagers is mainly comprised of rice with vegetables, where As is mainly present as inorganic species. The consumption of rice is the major source of dietary intake of inorganic As. Though, vegetables consumption does not pose significant health threat to the population independently, nevertheless it can increase the total daily intake of inorganic As (TDI-iAs) largely. Even, when people are drinking water with As concentration <10 µg L^-1, in 35% cases TDI-iAs exceeds the previous World Health Organization (WHO) recommended provisional tolerable daily intake (PTDI) value of 2.1 µg day-1 kg^-1 BW. At this As concentration level in drinking water, rice and vegetables together contributes 80% of the TDI-iAs irrespective of age of the participants. When As concentration in drinking water exceeds 50 µg L^-1, drinking water becomes the major contributor to the TDI-iAs. This study further assesses that level of adverse non-carcinogenic health effects and cancer risk among the population due to intake of inorganic As through consumption of rice and vegetables are significantly higher compared to the guidelines set by US Environmental Protection Agency (USEPA). This study suggests that only supply of As safe drinking water among the population is not enough to mitigate As menaces in the rural villages of Bengal. Any effort to mitigate the As poisoning of rural villagers in Bengal must look beyond the drinking water and consider all the routes of exposure.