Distribution dynamics and descriptive statistical analysis of radionuclides in the farmland soils near mining areas in Southwestern Nigeria

Abstract

Human exposure to ionizing radiation in the environment is mainly due to naturally occurring radionuclides in the soils, building materials and rocks, but the level may vary depending on the anthropogenic activities prevalent in each location. Presently, in Nigeria, there are concerns due to environmental health implications of all sorts of mineral mining and processing spreading across the southwestern states of the country. As a result, a total of 200 composite soil samples were taken in ve states in the southwest of Nigeria, close to active mining sites at the rooting (0.2 m) and at deep planting zones (0.5 m) for analysis by gamma-ray spectrometry using NaI(Tl) detector. The activity concentrations of natural radionuclides in the composite soil samples were determined to vary in the order of 40 K > 232 Th > 226 Ra/ 238 U for all locations. In contrast to the other locations, Olode and Igbokoda had average radium equivalent activities (Ra eq ) to be 1.6 and 1.8 times higher than the reference limit of 370 Bqkg − 1 . The estimated excess life cancer risk values were lower than the 0.29 x 10 − 3 global average value for soil by UNSCEAR and ICRP. A negative and low skewness value of 0.16 and 1.20 for 40 K and 232 Th were obtained in Olode and Sagamu. The kurtosis analysis of the activity concentrations was low and negative for soil at Itagunmodi for 40 K and 226 Ra/ 238 U; Olode for 40 K and 232 Th; and Igbokoda for 226 Ra/ 238 U and 232 Th where mining activities are common. The variation in the obtained results has been attributed to different agriculture practices and artisanal mining operations in each location.

Taxonomic Diversity and Functional Traits of Soil Bacterial Communities under Radioactive Contamination: A Review

“…The physical and chemical characteristics of the soil, such as moisture, pH levels, granulometric composition, temperature, oxygen levels, organic matter content, NPK levels, dominant vegetation, among others, play a pivotal role in shaping the adaptation of bacterial communities in radioactively contaminated soils [27,62,65,85,87]. Furthermore, the selection process is significantly influenced by the spectrum of radionuclides present and the spatial heterogeneity of contamination [18,112,347]. Assessing the contribution of ionizing radiation to community-based biological effects is only possible under strictly controlled laboratory conditions.…”