Assessment of Radiological Hazard Indices from Exposures to Background Ionizing Radiation Measurements in South-South Nigeria

Radioactivity in the environment from sources of natural and human activities resulting in planned, emergency and existing exposure to human population, environment and other biota has led to growing apprehensions in Nigeria and the world. The existing exposure situations mainly from natural radionuclides, present in the earth crust from creation emits background ionizing radiation leading to gamma dose exposures. The objective of this study was to assess the background ionizing radiation and associated radiological hazard indices in Itu, Nigeria located at 5010’0” N 7059’0” E, and establish an eco-radiological baseline data prior to the construction of any nuclear fission reaction facility in the area. A systematic random method of measurement was employed within demarcated monitoring zones of entire geological map of Itu, Nigeria. The global positioning system finder (GARMIN Etrex 10) was used for data point location, while RDS-31S/R Multi-purpose survey meter was used for dose rate measurement. The background ionizing radiation measurement obtained ranged from 0.041 ± 0.002 - 0.045 ± 0.002 μSv/hr with overall mean of 0.042 ± 002 μSv/hr, which was lower than the world mean of 0.2 μSv/hr. Radiological hazard indices arising from the background ionizing radiation measurement were also evaluated. The mean estimated Gamma Dose Rate was 9.312 nGy/hr, the terrestrial outdoor Annual Effective Dose Rate arising from gamma was 6.83 mSv/yr, that of indoor was 21.85 mSv/yr and Excess Life Cancer Risk was 0.05 × 10-3. The mean evaluated radiological hazard indices were found to be below admissible limits, and thus poses no significant radiological health threat to the populace. Therefore, the assessment demonstrates that there is no elevated level of dose rate, which is makes it safe for human habitation, but care should be taken to avoid increase radiation level from human activities. It is recommended that constant radiological monitoring be encourage, and the data considered as radiological baseline in Itu, Nigeria.