Quality and health risk evaluation for groundwater in Nadia district, West Bengal: An approach on its suitability for drinking and domestic purpose

The present work comprises the evaluation of twenty physico-chemical parameters in 110 ground water samples from 17 blocks of Nadia district located in West Bengal, for its quality assessment. A Water Quality Index (WQI) modelling has been done further where about 66% of water sample are not recommended for use. The mean anionic concentration range in groundwater seems to be in the order of HCO3 − > Cl− > CO3 2− > SO4 2− > NO3 − > PO4 3− which simplifies the water quality of Nadia district is allover alkaline and it is mainly because of bicarbonate alkalinity. Hardness is determined by Ca2+ and Mg2+ ions where calcium ion concentration (mean: 53.7 mg/l, range: 4–156 mg/l) overrules magnesium one (mean: 44.9 mg/l, range: 0.18–114 mg/l). Ground water in all the blocks is arsenic contaminated and maximum arsenic concentration is found to be 206 μg/l in Chakdah. Few ground water samples have been identified with presence of elevated level of nitrate (45–57.6 mg/l), particularly from four blocks (Krishnanagar-I, Nabadwip, Kaliganj and Chapra) in the district. No sample has been identified with uranium concentration (range: 0.21–20.9 μg/l) beyond its permissible limit (30 μg/l as recommended by WHO). Presence of high concentrations of Cl−, NO3 − and especially HCO3 − ions in groundwater and their positive interdependence with each other may magnify uranium contamination in future through dissolution of uranium as they are good carrier of uranium. The fluoride concentration has been observed within its recommended value in drinking water. There is a strong possibility for cancer risk through As and U in drinking water as the mean C.R value (1.2*10−3 and 2.48*10-3) goes beyond their respective acceptance level. Apparently there is no health risk from F− but in few cases NO3 − poses non carcinogenic health hazards in future. © 2020