Radiological Risk Assessment of Soil Using RESRAD-OFFSITE Code in Communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria

Abstract

Anthropogenic activities around a fertilizer company can cause elevation in the concentration of naturally-occurring radioactive materials (NORMs) within surrounding soils, as a result of effluent discharge or heaping of rocks used as raw materials. The aim of this study was to evaluate the human risk associated with exposure to NORMs in soils from communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria. A sodium-iodide doped with thallium [NaI(TI)] detector was used to measure activity concentrations of these NORMs in 22 soil samples within the study area. The residual radioactivity (RESRAD) offsite modeling program(version 4.0) was then used to estimate the radiation doses and the cancer morbidity risk of uranium-238 (238U), thorium-232 (232Th) and potassium-40 (40K) for hypothetical resident farmer scenario. According to the RESRAD prediction, the maximum total effective dose equivalent (TEDE) during 100 years was found to be 2.82 x 10-5 mSvy-1 at year 12, while the maximum total excess cancer morbidity risk for all the pathways was 3.52E-08 at year 6. Therefore, results obtained from the RESRAD-OFFSITE code in this study has shown that the health risk from effluent discharge within the study area is within acceptable levels according to international standards.