SHRUTI K 01 01 Naturally occurring radon gas 222Rn exists in groundwater and previous study of the problem of natural radioactivity in drinking water from wells drilled in rock types rich in uranium has shown tendency to have high radon concentration It has been widely reported that radon is contributing the largest component of human exposures to natural radiation and it is considered as the second major cause of lung cancer after cigarrete smoking Seventeen 17 groundwater samples around Mika Uranium mineralization were collected and 222Rn concentrations were measured using the DURRIDGE RAD7 electronic radon detector Radon 222Rn concentrations in the groundwater ranged from 2350 to 46200 Bqm3 with an average of 29400 Bqm3 The results show that 765 of the groundwater samples collected have 222Rn concentrations far above the USEPA maximum contaminant level MCL of 111 Bql for states without radon monitoring policy and enhanced indoor air programs while 235 has values lower Meanwhile all 222Rn values were below the MCL of 100 Bql recommended by European Union EU for measurements that warrant consideration of possible remedial actions Borehole samples show relatively higher 222Rn concentrations than samples collected from openwells The annual effective dose due to ingestion Hing of 222Rn in the groundwater ranged from 005 to 092 mSv with an average of 059 mSv These values are within the ICRP recommended reference level of 1 mSvyr for the intake of radionuclide in water by the general public for a prolonged exposure Copyright (c) Journal of Science Engineering Technology and Management Science. All rights reserved 2026