Assessment of Human Health Risks from Arsenic Contamination in Groundwater-Soil-Crop System of a Humid Sub-Tropical Region in India

Arsenic (As) pollution has become a global concern due to its toxic and carcinogenic nature. Even at relatively low concentrations, arsenic can cause acute and chronic human toxicity. In the current study, samples of groundwater, soil at three depths (top, 50cm, and 150 cm), and grains were collected from a humid sub-tropical region in India encompassing Ballia, Deoria, and Mau districts in the state of Uttar Pradesh. All the samples were analyzed for arsenic employing Inductively Coupled Plasma Mass Spectrometry (ICPMS-MS). 60.3% of groundwater samples exceeded the Bureau of Indian Standards (BIS) permissible limit of 10 μg/l. 40% of soil samples were above the mean background concentration for arsenic in the soil as indicated by the Indian Agricultural Research Centre (IARC), i.e., 5 mg/kg. Further, Human Health Risk Assessment (HHRA) was evaluated in four stages: hazard identification, dose-response assessment, exposure assessment, and risk characterization. HHRA estimates the nature, magnitude, and probability of arsenic impacts in the present and the future. Chronic Daily Intake rate (CDI) was determined to assess the exposure, which depends on the mobility of arsenic in groundwater→soil→crop system. The gradual increase in arsenic contamination in groundwater, mostly used in irrigation, finds its way to the food chain either via drinking or cooking, which is a matter of concern for humans. For risk assessment, Total cancer risk (TCR) and Hazard Index (HI) were computed. Finally, the study estimated the cancerous and non-cancerous risks from arsenic toxicity in groundwater-soil-crop system to human adults and children. The cancerous risk for arsenic contamination was in the order of adults>children due to long-term exposure to arsenic by adults. In contrast, the non-cancerous risks for adults and children exceeded the threshold value of 1 provided by the U.S. Environmental Protection Agency (USEPA), specifying a high health risk rate (children>adults). Apparently, children are more sensitive to chemicals in comparison to the adaptability of adults, and hence, they are most affected. It is envisaged that studies like this, which examine scenarios of elevating probabilities of health risks in children and adults from arsenic-contaminated groundwater, soil, and crops, would enable more rational and decisive actions from the concerned stakeholders for arsenic management in the future.