Natural radioactivity in the newly discovered high background radiation area on the eastern coast of Orissa, India

High levels of natural radiation areas occur in some parts of coastal tracts of India. The newly discovered Erasama beach placer deposit, part of the eastern coast of Orissa State, India is a high natural background radiation area, due to the presence of radiogenic heavy minerals. The average activity concentrations of radioactive elements such as <f>232Th</f>, <f>238U</f> and <f>40K</f>, measured by gamma-ray spectrometry using an HPGe detector, and found to be <f>2825±50</f>, <f>350±20</f> and <f>180±25 Bq kg−1</f>, respectively, for the bulk sand samples. The absorbed gamma dose rates in air due to the naturally occurring radionuclides varied from 650 to <f>3150 nGy h−1</f> with a mean value of <f>1925±718 nGy h−1</f>. The annual external effective dose rates for the region varyed from 0.78 to <f>3.86 mSv yr−1</f> with a mean value of <f>2.36±0.88 mSv yr−1</f>. The external gamma dose rate level of Erasama coastal region is similar to the other monazite sand bearing high background radiation areas of southern and southwestern coastal regions of India. The major contributors to the enhanced level of radiation are monazites and to a lesser extent in zircons. [Copyright &y& Elsevier]