Radiological and hydrological implications of dissolved radon in alluvial aquifers of western India

A study was undertaken to measure the dissolved radon ( 222 Rn) concentration in parts of western India (Southwest Punjab) in order to evaluate its hydrological and radiological implications. Radon was monitored using Smart Radon Monitor in 25 locations. The dissolved 222 Rn concentrations ranged from 618 to 3210 Bq/m 3 in the groundwater and were well below the USEPA maximum contaminant level of 11,100 Bq/m 3 and an alternate maximum contaminant level of 148,000 Bq/m 3 . Radiological dose due to dissolved radon was calculated and the results indicated that the estimated total annual effective dose (both from ingestion and inhalation) varied between 6.07 and 31.52 μSv/year, which is within the recommended limit of 100 μSv/year prescribed by WHO and EU Council ( 1998 ). This infers that there is no significant radiological risk due to dissolved 222 Rn for the inhabitants of this region. 222 Rn showed a negative correlation with corresponding U concentration while with other hydrochemical parameters the correlations were either weak or insignificant. The depth variation of dissolved 222 Rn concentration indicated that shallow zone has a wider range of radon values as compared to deeper zone. Spatial and hydrochemical trends signify that 222 Rn concentration is not only controlled by a variety of geochemical processes but also by surface processes.