Evaluation of Radon (222Rn) Concentration in Drinking Water and Its Radiological Health Implications in Hirehalli Industrial Area, Tumkur, Karnataka, India
Abstract: Radon-222 (222Rn) in groundwater is an important source of natural radiation exposure, particularly in regions underlain by crystalline rocks. This study investigates dissolved 222Rn activity concentrations in drinking-water sources and the associated radiological exposure in the Hirehalli Industrial Area, Tumakuru, Karnataka, India. Water samples were collected from 15 representative locations and analysed using an emanometry technique coupled with a Lucas scintillation cell. The measured 222Rn activity concentrations ranged from 10.91 to 36.71 Bq L-1, with an arithmetic mean of 21.82 ± 6.88 Bq L-1 and a geometric mean of 20.82 Bq L-1. All measured concentrations were below the 100 Bq L-1 parametric value specified in the European drinking-water framework, although 14 of the 15 locations exceeded 11.1 Bq L-1, corresponding to 300 pCi L-1 used in the U.S. Environmental Protection Agency's proposed radon-in-drinking-water rule. Annual effective doses due to inhalation of radon released from water and direct ingestion were estimated using UNSCEAR-based parameters. The inhalation dose ranged from 27.52 to 92.40 μSv y-1, whereas the ingestion dose ranged from 2.30 to 7.68 μSv y-1. The combined annual effective dose ranged from 29.83 to 100.85 μSv y-1, with a mean of 59.60 ± 18.89 μSv y-1. Inhalation accounted for approximately 92.2% of the mean total effective dose, indicating that radon transferred from water to indoor air is the dominant exposure pathway in the adopted assessment. The highest 222Rn concentration and total dose were observed at location L11. Overall, the measured concentrations were below the 100 Bq L-1 screening value considered in the European regulatory framework. Periodic monitoring, particularly at comparatively elevated locations, together with seasonal sampling and complementary measurements of 226Ra, uranium, hydrochemical parameters and indoor-air radon, is recommended to improve assessment of radiological exposure and source attribution.
Keywords: Radon-222; drinking water; groundwater; Lucas scintillation cell; radiological assessment; annual effective dose; Hirehalli Industrial Area
How to Cite?: Nagabhushana S R, Sandeep Dongre, "Evaluation of Radon (222Rn) Concentration in Drinking Water and Its Radiological Health Implications in Hirehalli Industrial Area, Tumkur, Karnataka, India", Volume 14 Issue 12, December 2025, International Journal of Science and Research (IJSR), Pages: 2477-2481, https://www.ijsr.net/getabstract.php?paperid=SR251122102959, DOI: https://dx.doi.org/10.21275/SR251122102959