Determination of uranium isotopes in ground water by alpha spectrometry and associated age dependent ingestion dose

Determination of uranium isotopes in ground water plays a key role in assessment of the geochemical condition of the ground water and to estimate ingestion dose to general public due to intake of uranium through drinking water pathway. In the present study an attempt has been made to estimate isotopic composition and activity ratios (AR) of uranium isotopes in ground water samples by alpha spectrometry. The associated age dependent ingestion dose was also calculated by using IAEA dose coefficient and taking the prescribed water intake value of different age groups. ²³⁸U, ²³⁵U and ²³⁴U activity concentration was found to be in the range of 5.85±1.19 –76.67±4.16, <0.90–3.15±0.84, and 6.52±1.25–107.02±4.92 mBq/L, respectively. Activity ratios of ²³⁴U/²³⁸U vary from 1.01 to 1.84 with a mean value of 1.36 which is close to unity that indicates uranium in the ground water is of natural origin. Uranium concentration was found to be in the range of 0.47±0.10 μg/L to 6.20±0.34 μg/L with an average of 3.01±0.23μg/L, which is much lower than the national and international guideline value. The annual ingestion dose due to uranium in drinking water for all age group ranges from 0.60 ± 0.11 to 19.50 ± 1.03 μSv/y. (author)