Assessment of uranium in correlation with physico-chemical properties of drinking water of Northern Rajasthan

In the present study, analysis of 238U concentration in 40 drinking water samples collected from different locations of Jodhpur, Nagaur, Bikaner and Jhunjhunu districts of Rajasthan, India has been carried out by using high resolution inductively coupled plasma mass spectroscopy (HR-ICP-MS) technique. The water samples were taken from hand pumps and tube wells having depths ranging from 50 to 800 feet. The measured uranium concentration lies in the range from 0.89 to 166.89 μg l^-1 with the mean value of 31.72 μg l^-1. The measured uranium content in twelve water samples was found to be higher than the safe limit of 30 μg l^-1 as recommended by World Health Organization (WHO, 2011) and US Environmental Protection Agency (USEPA, 2011). Radiological risk calculated in the form of annual effective dose estimated from annual uranium intake ranges from 0.66 to 138.63 μSv y^-1 with the mean value of 26.28 μSv y^-1. The annual effective dose in two drinking water samples was found to be greater than WHO (2004) recommended level of 100 μSv y^-1. Chemical risk calculated in the form of lifetime average daily dose (LAAD) estimated from the water samples varies from 0.02 to 4.57 μg kg^-1 d^-1 with the mean value of 0.87 μg kg^-1 d^-1. The lifetime average daily dose (LAAD) of ten drinking water samples was found to be greater than WHO (2011) recommended level of 1 μg kg^-1 d^-1. The corresponding values of hazard quotient of 48% water samples were found to be greater than unity.A good positive correlation of uranium concentration with total dissolved solids (TDS) and conductance has been observed. However no correlation of uranium concentration with pH was observed. The results revels that uranium concentration in drinking water samples of the study area can cause radiological and chemical threat to the inhabitants.