Primordial radionuclides concentrations in the beach sands of East Coast region of Tamilnadu, India

Abstract The Eastern coastal region of Tamil Nadu (8°11′N to 13°04′N latitude, 77°29′E to 80°17′E longitude) India is known to have some of regions of significant distribution of monazite. A total of 66 sand samples have been collected from 33 locations situated 25–30 km apart. By γ-ray spectrometry using NaI(Tl) detector, activity concentrations of primordial radionuclides such as 40 K, 232 Th, and 238 U have been determined as 15 to 524 Bq kg −1 , 13 to 3576 Bq kg −1 and BDL to 254 Bq kg −1 . Depth profile study has been also carried out. Abnormal values of thorium concentrations have been observed at Kanyakumari (1315 Bq kg −1 ), Kudankulam (2860 Bq kg −1 ), Uvari (1225 Bq kg −1 ), Tharangampadi (3576 Bq kg −1 ) and Pondicherry (1641 Bq kg −1 ). The absorbed γ-dose rate above 1 m due to the presence of these primordial radionuclides has been found to be in the range of 12–2337 nGy/h. Subsequently, the annual effective dose has been found to vary from 0.014 to 2.87 mSv/y.