The South Peninsular India is known to have very high levels of natural background radiation due to the monazite rich beach sand. Primordial uranium is ubiquitous and the heaviest radio toxic trace element available in all terrestrial substances at varying levels depending on the geology of the region. Uranium series supports several short-lived radioisotopes during its decay including radium. Uranium in drinking water is important in terms of the ingestion dose also. This report depicts the results of uranium analysis of 600 water samples collected from the south coast peninsular region extending parts of Kerala and Tamilnadu states of India through fission track registration technique. Results of the analyses of water samples collected from different sources in the south coast of India show that uranium concentrations vary from 0.82 µg/l to 7.32 µg/l equivalents to the specific activity of 10.33 Bq/m 3 and 92.23Bq/m 3 , respectively. Estimated daily intake of uranium through drinking water ranges from 20.22 to 18.58mBq/kg and is lower than the recommended limits of intake. The heterogeneity in distribution of uranium in water bodies is due to the presence of monazite sand deposited in the coast over the years.

Knowledge on the distribution of these radionuclides in soil is of great importance for radiation protection and measurement. A systematic radiological survey has been carried out in the region of HBRAs in Kollam district of Kerala and Manavalakurichi in Tamilnadu in India to compare the natural gamma-radiation levels. 180 soil samples collected and were analyzed for 238U, 232Th and 40K by NaI(Tl) gamma-ray spectrometry. Heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of soil in the region. The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples. From these radioactivity levels, the radium equivalent activity and the external hazard index which resulted from the natural radionuclides in sediments are also tabulated for the analyzed samples and compared with internationally recommended values.