Natural radioactivity and radiation exposure in the beach placer deposit of southeastern coastal Orissa, India

The newly discovered Balipatana beach placer deposit, southeastern coastal parts of Orissa State have a high natural radiation environment due to the presence of radiogenic heavy minerals. The concentrations of radioactive elements such as 232Th, 238U and 40K were measured by gamma ray spectrometry, using a High Purity Germanium detector. The average activity concentrations of 232Th, 238U and 40 K are found to be 1900 100, 250±50 and 10020 Bq/kg, respectively, for the total sands. The average activity concentrations of monazites and zircons were 280000±750 and 2000±100 Bq/kg for the 232 Th and 20000±250 and 3200±150 Bq/kg for the 238 U, respectively. The external gamma radiation dose was computed by using dose conversion factors given by UNSCEAR (1993). The mean absorbed dose rates in air due to naturally occurring radionuclides are 1425 ±75nGyh-1 and the effective doses are estimated to be 8.5±0.6 mSv/yr. This studies shows that the Balipatana placer deposit of southeastern coast of Orissa have high natural radioactivity and external gamma dose rate levels, similar to the high background radiation areas along different parts of India like, Manavalakkurichy in Tamilnadu and Chavara in Kerala state and other different parts of world