Assessment of radiation hazard indices due to natural radioactivity in soil samples from Orlu, Imo State, Nigeria

Abstract

The use of a Radiation Alert Inspector device and a gamma-spectrometry system fitted with a Sodium Iodide (NaI) detector was used to determine the radioactivity concentration level of natural radionuclides 238 U, 232 Th, and 40 K in soil in several locations in Orlu, Imo State, Nigeria. 19 soil samples were collected for analysis from several locations of factories, agricultural farming-lands, gullies and water eroded areas, and soil deposits very close to flowing waters from rocks, due to environmental concerns arising from human activities in this region. The activity concentration values for 238 U, 232 Th, and 40 K were found to range from 0.14 to 9.34 Bq.kg −1 , 0.03–3.75 Bq.kg −1 , and 16.83–783.06 Bq.kg −1 , respectively, with average mean values of 4.15, 1.64, and 134.13 Bq.kg −1 . Radium equivalent activity, absorbed dose rate, and gamma index mean values for the samples were 16.822 Bq.kg −1 , 8.528 nGyh -1 , and 0.133 mSv respectively, the obtained values were below the safe limit values set by the United Nations Scientific Committee on the Effects of Atomic Radiation of 370.0 Bq.kg −1 , 59.0nGyh −1 , and 1.0 mSv. According to the findings, the regions under study are reasonably safe for human outdoor activities such as agriculture, construction, and factory operations.

Measurement of Natural Radioactivity and Assessment of Radiological Hazard Indices of Soil Over the Lithologic Units in Ile-Ife Area, South-West Nigeria

“… 54 The average concentration of 232 Th obtained in this study is lower than those obtained in other parts of the country except for Imo State. 48 - 54 However, 40 K average concentration in the present study is higher than those obtained in most part of the country except for Ondo State.…”

“…Comparison of the level of radionuclide concentrations obtained in this study with similar studies previously carried out in Nigeria by other researchers is shown in Table 2 . The study revealed that average 238 U concentration in this study is higher than those obtained in parts of Imo, Ondo, Edo, and Benue 48 - 54 States. The value however compares with the average value obtained for the 6 geopolitical zones of Nigeria.…”

Measurement of the natural radioactivity content of earth pigments and evaluation of radiological health risks

“…Worth of note, the AEDE was calculated for both "outdoor" and "indoor" exposure [27], in order to take into account all possible exposure contexts, i.e. archaeological sites, museums, churches, in which these pigments can be found [28].…”

Radiological impact assessment due to background ionizing radiation around palm oil processing mills in southwestern Nigeria

“…Background ionizing radiation was initially present in human surroundings because natural terrestrial radionuclide and extraterrestrial cosmic radiation sources had been enhanced over the years due to various human activities, especially in industrialized areas. These enhanced radiation levels in the human environment expose them to acute radiological hazards [16,17].…”