Water radon risk in Susunia hill area: an assessment in terms of radiation dose.

Radiological impact of radon in air is a global issue whereas radon in water has local consequences. Considering its importance, we have conducted a study on radon activity measurements in 316 tube-well water samples collected from Susunia hill area in Bankura district of West Bengal, India during the period of 25th December 2018-2nd February 2020. Radon contents are measured using AlphaGUARD radon monitor. The obtained radon activities in drinking water samples lie between 1.78 ± 0.07 and 3213.50 ± 77.32 Bq/l with an average of 128.30 ± 14.09 Bq/l. This study reveals that 93% of the samples have radon levels in excess of the USEPA proposed maximum contamination level (MCL) of 11.1 Bq/l while radon levels of 40% samples have exceeded the WHO and EU Council Directive recommended reference level of 100 Bq/l. The total annual effective dose of the samples have been estimated by considering the per day water intake of 3 l. The calculated total annual effective dose widely fluctuates between 10.39 and 18649.55 μSv/year with an average value of 744.59 μSv/year. 269 water samples have exceeded the WHO and EU Council Directive recommended reference level of 100 μSv/year. However, if we consider the UNSCEAR prescribed annual water intake of 60 l, the average dose becomes 279.82 μSv/year. The situation demands attention of the local authorities. Local people are advised to take some easy preventive measures for their radiological protection against such contamination.