Natural radioactivity in Udupi and Karkala Taluks of coastal Karnataka

Abstract

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The gamma radiation levels, ²²⁶Ra, ²³²Th and ⁴⁰K concentrations in soils of Udupi and Karkala Taluks of coastal Karnataka region of India have been studied in the present paper. The gamma absorbed dose rates were measured using portable GM survey meter. The soil radioactivity was measured by gamma spectrometry method using an HPGe detector. The results show that the ²²⁶Ra concentration varies in the range 2.6-78.0 Bq kg^-1 with a mean of 34.4 Bq kg^-1, ²³²Th in the range 2.3-166.2 Bq kg^-1 with a mean of 45.3 Bq kg^-1 and ⁴⁰K in the range 72.9-493.5 Bq kg^-1 with a mean of 198.6 Bq kg^-1in the 0-5 cm soil profile. The gamma absorbed dose rates, measured using the GM survey meter, show that the dose varies in the range 70.0-123.0 nGy h^-1. The regression analyses performed between the measured dose rates and that calculated from the primordial radionuclide activities show a poor correlation between the measured and calculated dose.

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