A study on the radon content of the surface and groundwaters in southern part of Calcutta

The radon level of the surface and groundwaters has been determined in the southern part of Calcutta in 1976. The experimental setup is made highly sensitive so as to monitor the activity upto the range of 10sup(-17) curies per litre. The mean activities in this area are 0.569, 0.404, 0.458 and 0.988 pico-curies respectively for the samples from the surface, 30.5 m., 152.5 m and 244 m. depth. The chlorides and the total dissolved substances in the samples vary with the depth as the radon content does. The activity of the samples from the Bengal Lamp area, which is just below the permissible limit, gives out a sharp peak above the mean value. It is considered that this is arising out of some external contamination and is likely to be derived from some radioactive wastes from the nearby laboratories. (auth.)