ASSESSMENT OF AGE-DEPENDENT RADIATION DOSE DUE TO INTAKE OF URANIUM AND THORIUM IN DRINKING WATER FROM SIKAR DISTRICT, RAJASTHAN, INDIA

The concentrations of U-238 and Th-232 have been determined in drinking water samples collected from the Sikar district of Rajasthan State, India. The samples have been analysed by using high-resolution inductively coupled plasma mass spectrometry. U-238 content in water samples ranged from 8.20 to 202.63 A mu g l(-1) and Th-232 content ranged from 0.57 to 1.46 A mu g l(-1). The measured U-238 content in 25 % of the analysed samples exceeded the World Health Organization (WHO) and United States Environmental Protection Agency drinking water guidelines of 30 A mu g l(-1) and 12.5 % of the samples exceeded the 60 A mu g l(-1) Indian maximum acceptable concentration recommended by the Atomic Energy Regulatory Board, India. The annual effective doses (A mu Sv y(-1)) due to ingestion of U-238 and Th-232 for different age groups were also calculated. The results compared with the recommended value reported by the WHO.