Occurrences of NORMS and¹³⁷Cs in soils of the Singhbhum region of Eastern India and associated Radiation Hazard

Abstract

Naturally occurring radioactive materials (NORMS) and fallout 137Cs were estimated in surface soils from the highly mineralized Singhbhum region of Eastern India. The activity concentrations varied from 50.67-109.14 Bq/kg (238U), 48.12-142.55 Bq/kg (226Ra), 28.73-89.78 Bq/kg (232Th), 494.84-1121.36 Bq/kg (40K) and 1.8-7.48 Bq/kg (137Cs). Correlation between radionuclides was studied. 232Th/238U concentration (Clark value) was also calculated. Radiation hazard for the samples was assessed by radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin) and absorbed gamma dose rate (D). Raeq values ranged from 216-263 Bq/kg, Hex values from 0.58-0.71 Bq/kg, Hin values from 0.73-1 Bq/kg and D values from 100-121 nGy/h. Calculated and observed dose rates in air were compared with the help of parametric and non-parametric tests. The tests showed significant difference between the calculated and observed dose rates.