222Rn concentration in ground waters of coastal Karnataka and Kaiga of south west coast of India

Groundwater (open well and bore well) samples from various locations of coastal Karnataka and Kaiga have been investigated for their Rn-222 concentrations by emanometry method. The concentration of 222Rn in open well water was found to vary in the range 0.14-25.4 Bq L-1 with a median value of 3.74 Bq L-1 and that in bore well water in the range of 0.22-197.0 Bq L-1 with a median value of 5.75 Bq L-1. From the measured concentrations the effective doses for the population of the region were estimated. The effective dose was found to vary from 0.09 mu Sv y(-1) to 204.2 mu Sv y(-1) for open well water consumers and from 0.2 mu Sv y(-1) to 1586.9 mu Sv y(-1) for bore well water consumers. The results of the present study are also compared with the literature values and discussed.