Natural radioactivity in crude oil–spilled soils of Baralue and Korokoro communities, Ogoniland, Nigeria, and the assessment of radiological risks using Monte Carlo simulations

Abstract

Radiation measurements and their health hazard assessments were carried out in the crude oil spill-affected communities of Baralue and Korokoro in Ogoniland, Rivers State, Nigeria. The study utilized both in situ and laboratory methods. In situ measurements were taken with a GQ GMC–500/GMC–500 + digital Geiger Muller counter, while a cesium iodide (thallium-doped) gamma-ray spectrometer was used for laboratory measurements. Data were collected from forty (40) locations within the creeks with a history of crude oil spillage and ten (10) locations with no such history serving as control. For the in situ method, both the annual effective dose equivalent (AEDE) and excess lifetime cancer risk (ELCR) in the crude oil–impacted communities were higher than those in the non-crude oil–impacted areas, and all values are lower than the global average background radiation dose of 0.48 mSv year⁻¹. Laboratory methods measured activity concentrations of naturally occurring radionuclides (⁴⁰ K, ²³²Th, and ²²⁶Ra) to compute radiological parameters such as D_out, AEDE, R_aeq, AGED, AUI, I_γ, H_out, H_in, and ELCR. These results indicated a slight increase in radiation levels and health hazards in the crude oil spillage areas compared to non-spillage areas, although they remained below the world permissible levels. This suggests that crude oil spillages may have altered natural radiation concentrations and increased radiological health hazards in the impacted areas. Additionally, in situ measurement values are higher than laboratory measurement values due to environmental radiation interference, unlike the controlled laboratory environment where gamma radiation was shielded from environmental and cosmic interference. Monte Carlo simulation results show that the study area has a minimal probability of cancer risks to the public as a result of exposure to external radiation.