Exploring the potential health risks of groundwater arsenic and its spatial distribution in three districts (Patna, Bhojpur and Saran) of Bihar, India.

Groundwater arsenic contamination and associated health risks are a major concern worldwide, particularly in South and Southeast Asia. The present investigation is a first time attempt to assess the potential health risks of groundwater arsenic and its spatial distribution in Patna, Bhojpur and Saran districts of Bihar, a high arsenic endemic region in India. Arsenic was quantified in groundwater samples using the Atomic Absorption Spectrophotometer along with visualization of its spatial distribution through Inverse Distance Weighted method. It was followed by the analysis of water quality of collected samples following standard protocols. The potential health risks of arsenic exposure were calculated following USEPA guidelines. Bhojpur district emerged with highest percentage (53.34%) of groundwater samples having arsenic above WHO permissible limit (0.010 mg/l) followed by Saran district (28.58%) and Patna district (22.54%). Areas with high arsenic level were more extensive in the Bhojpur district than Saran and Patna districts and were confined to the regions close to river Ganga representing northwestern, northeastern and southeastern regions of Bhojpur, Patna and Sonepur region of Saran districts respectively. The physico-chemical parameters exhibited high alignment with arsenic mobilization in three districts. The health risks (both non-cancer and cancer) were high in all the three districts with more severity in Bhojpur district. Assessment by risk thermometer also corroborated the existence of high risk in Bhojpur district compared to Saran and Patna districts. Both non-cancer and cancer risks were higher among children than adults in all the three districts.