Radiological safety assessment of drinking water in Darjeeling hill and foothill areas: An experimental finding

Abstract

Abstract This study intends to shed light on the radiological quality of potable water in one of the most important hill stations, Darjeeling, and its surrounding foothill areas of West Bengal, India, which has not yet been explored. A radon concentration measuring study has been carried out in 62 water samples collected from both natural springs (SW) and tube wells (TW) in the above mentioned area using an AlphaGUARD radon monitor. The measured maximum and minimum radon levels of drinking water samples collected from natural springs are 13.04 Bq/l and 0.43 Bq/l respectively while those for tube wells are 71.02 Bq/l and 1.02 Bq/l respectively. The average radon activities in the two water sources separately and together are 2.88 ± 0.41 and 25.67 ± 3.89 and 10.96 ± 1.97 Bq/l respectively. This study reveals that the average radon concentrations of water samples from both sources in this area are much below the reference level of 100 Bq/l as prescribed by the WHO and EU Commission. The evaluated radon activities are used to determine inhalation, ingestion and then total annual effective dose (AED). The average total AEDs for the two types of water sources separately and together (SW + TW) are 7.86 ± 1.11, 70.07 ± 10.64 and 29.93 ± 5.37 μSv/y respectively. The evaluated average total AEDs for the two types of drinking water sources separately and together are also much below the reference limit of 100 μSv/y prescribed by the above mentioned two agencies. It suggests that the drinking water of this region is radiologically safe so far as water-borne radon hazards are concerned.