Assessment of uranium levels and associated health risks in drinking water from various aquifers in northeastern Rajasthan, India

The uranium levels were investigated in 350 drinking water samples from different aquifers (alluvium, quartzite, limestone, slate, phyllite and schist, hornstone breciss, and granite) in northeastern Rajasthan, India. The LED Fluorimeter (model: LF-2a) technique was employed to determine the uranium levels in the drinking water samples. The uranium concentrations range from 0.62 to 128.63, 0.58 to 99.35, 0.79 to 54.40, 0.61 to 41.35, 2.63 to 3.30, 0.57 to 46.24, and 1.01 to 11.98 µg/L, with mean values of 15.95, 9.14, 14.90, 9.70, 2.97, 12.72, and 4.96 µg/L, respectively, for the alluvium, quartzite, limestone, slate, phyllite and schist, hornstone breciss, and granite aquifers. Uranium concentrations across the studied area varied between 0.57 and 128.63 µg/L, with an average of 13.68 µg/L. About 11.14 % of the samples surpassed the World Health Organization's recommended limit (30 µg/L). The radiation dose was calculated by considering the water intake of various age groups, and found infants received the highest calculated dose. On the radiological aspect, two groundwater samples from an alluvium aquifer exceeded the prescribed level (1.67 × 10^-4) recommended by the Atomic Energy Regulatory Board of India. The average daily dose of uranium from drinking water ranged from 0.02 to 3.68 µg/kg/day. Approximately 8.3 % of the samples from different aquifers surpassed hazard quotient values of unity and indicated chemical toxicity risks. Uranium levels showed no correlation with physicochemical parameters in all the aquifers.