A Comparative Study of Naturally Occurring Radionuclides and Uranium Activity Ratio in Soils of High Background Radiation Area of India with Fukushima Soils

Naturally occurring radionuclides such as 238U, 232Th and 40K, are ubiquitous in the Earth’s crust and are incorporated in radiogenic minerals such as monazites, ilmenite, rutile, sillimanite and zircon. The areas with radiogenic minerals deposition are responsible for the enhanced natural background radioactivity and widely known as high background radiation areas (HBRA). In India, monazite is abundantly present in placer deposits along the coast of Kerala (southwestern), Odisha (eastern coast) and Tamilnadu (Southeastern). Radiological investigations have been carried out in coastal HBRAs of Odisha and Tamilnadu and extra terrestrial gamma dose rate varied from 0.1 to 1.6 µSv h-1. Natural radionuclide contents in selected surface soil samples were determined using HPGe (High purity germanium) detector and inductively coupled plasma mass spectrometry. The radiation hazard parameters were evaluated from activity concentration of 238U, 232Th and 40K [1]. Uranium concentration and activity ratios were compared between HBRA soils with Fukushima contaminated soils due to 137Cs where dose rate varied from 0.5 to 85 µSv h-1. Uranium isotopes ratios were measured using thermal ionisation mass spectrometry [2].Ref.[1] United Nations Scientific Committe on the Effects of Atomic Radiation (UNSCEAR), Sources and Effects of Ionizing Radiation;. Vol. 1 New york, United Nations (2000).[2] Mishra S., Kasar S., Takamasa A., Veerasamy N. and Sahoo S.K.: Measurement of uranium distribution coefficient and 235U/238U ratio in soils affected by Fukushima dai-ichi nuclear power plant accident;. Journal of Environmental Radioactivity 198(2019), pp.36-42.3rd International Conference “RADON IN THE ENVIRONMENT2019