Measurement of radon-222 and radium-226 in well water of Kelantan

Abstract

The Environmental Protection Agency (EPA) of USA sets the Maximum Contamination Level (MCL) for 222Rn in drinking water to be 11.1000 Bq/l and for 226Ra to be 0.1100 Bq/l. This study was conducted to determine the levels of 222Rn and 226Ra in private well water in the state of Kelantan. A total of 25 samples of well water were collected from various districts in the state. The levels of 222Rn and 226Ra dissolved in well water were measured using the liquid scintillation counting technique. 222Rn activity concentrations were found within the range of 0.0491 to 4.3127 Bq/l for both unfiltered and filtered samples. Meanwhile, activity concentration of 226Ra measured is between 0.0278 to 1.9670 Bq/l for both unfiltered and filtered samples, exceeding the MCL value. The annual effective doses due to the intake of natural radionuclide from well water for three different age groups were estimated based on the amount of water consumed. The average annual effective dose of 226Ra calculated for babies in the range of 0.12 to 1.79 µSv/y. The average annual effective dose of 226Ra for children was in the range of 0.11 to 0.34 µSv/y while, for the adults, it was in the range of 0.11 to 0.33 µSv/y for 226Ra. The annual effective dose intake for the babies was found to be higher than other groups but within the limit recommended by World Health Organization (WHO). The doses for the other two groups are below the recommended value.