Measurement of Surface Dose Rate of Nuclear Radiation in Coastal Areas of Akwa Ibom State, Nigeria

Abstract

In this study, the surface doses rate measurements were done in-situ using dose rate meters. The analysis of naturally occurring radionuclides (40K, 238U and 232Th) has been carried out in soil samples collected from Eastern Obolo, Ikot Abasi, and Ibeno local government areas of Akwa Ibom State, using gamma spectroscopy operated on a Canberra vertical high purity 2’’×2’’ NaI(Tl) model 802 detector. The activity concentration (Bq.kg-1) of the samples ranges from 34.65±2.56 to 214.12±4.34 with mean value 94.60±3.42 for 40K, 5.12±0.38 to 38.5±2.38 with mean value 15.16±1.83 for 238U and 0.03±0.77-30.59 with mean value 15.40±0.73 for 232Th. This study also examines some radiation hazard indices, the mean values obtained are 44.46 Bq.kg-1, 20.52 nGy.h-1, 0.02 mSv, 0.17 Bq.kg-1, 0.20 Bq.kg-1 for Radium Equivalent activity (Raeq), Absorbed Dose rate (D), Annual Effective Dose Rate (Eeff Dose), External Hazard index (Hex) and internal Hazard index (Hin) respectively. These calculated hazard indices to assess the potential radiological health risk in soil and the dose associated with it are well below their permissible limit. The soil and sediments from the study area provide no excessive exposures for inhabitants and can be use as construction material without posing any immediate radiological threat to the public. However, the public is cautioned against excess exposure to avoid future accumulative dose of these radiations.