Groundwater Fluoride Dynamics and Potential Risk of Fluorosis in Schoolchildren: An Extensive Study from the Fluoride Endemic Region of Chota Nagpur Plateau, Jharkhand, India

Groundwater fluoride (F – ) contamination was reported earlier from the Chota Nagpur Plateau, Jharkhand, India; however, detailed information was missing for precise identification of contaminated zones and associated health risks. The present study investigated F – contamination across the Gharbar gram panchayat, Baliapur block, Dhanbad district, focusing on groundwater hydro-geochemistry, schoolchildren’s Intelligence Quotient (IQ), and health risks. About 36% of groundwater samples ( n = 315) exceeded 1.5 mg/L F – (mean = 1.68; range = 0.02–16.2). Out of the six studied villages in Gharbar gram panchayat, Gharbar exhibited the highest contamination index. Elevated Na + and depleted Ca 2+ levels indicated weathering-induced dissolution of CaF 2 as a possible source of F – under alkaline conditions. Most contaminated wells were located between 6.1 and 76.2 m depth. Fluoride accumulation was maximum in leafy vegetables and posed limited dietary risk. Urinary F – was strongly correlated with water F – ( p < 0.001) and reached up to 21 mg/L. Cumulative hazard index indicated F – toxicity in the order: children > adults > teenagers. Dental and skeletal fluorosis were noticed among 50% of the studied schoolchildren ( n = 60), and out of them, 67% showed average (Grade III) intelligence levels. Findings revealed severe F – contamination that caused neurotoxicity and urgent safe drinking water initiatives.