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.