Evaluation of Environmental Radioactivity and Estimation of Radiation Exposure in the Niankhene Agricultural Field in Senegal

Abstract

The presence of radioactivity, originating from both natural and human-induced sources, is widespread in varying degrees throughout the Earth's crust. Soil, as a fundamental component of the Earth's crust, serves as an ongoing source of exposure to humans. The level of radioactivity in soil is influenced by factors such as soil composition and land usage. It is expected that barren soil exhibits distinct radioactivity levels compared to cultivated soil. To investigate the radioactivity levels within barren soil, a study was conducted on approximately 11 hectares of soil samples located in Niankhene. Utilizing gamma ray spectrometry methodology with a high purity germanium gamma-ray detector, activity concentration levels of radionuclides including <sup>40</sup>K, <sup>137</sup>Cs, <sup>226</sup>Ra, and <sup>232</sup>Th were evaluated. A total of 16 soil samples were collected at depths ranging from 0 to 40 cm with 20 cm intervals. The activity concentrations of the radionuclides were observed as follows: <sup>40</sup>K ranged from below the limit of detection to 34.7 Bq.kg<sup>-1</sup>; <sup>137</sup>Cs varied from 0.06 to 0.80 Bq.kg<sup>-1</sup>; <sup>226</sup>Ra measured was between 7.49 and 101.56 kg<sup>-1</sup>; and <sup>232</sup>Th ranged 0.33 and 12.68 Bq.kg<sup>-1</sup>. The total dose radiation exposure were 27 nGy/h in this study. Before conducting radiometric measurements, chemical analyses were performed to determine the concentrations of Na, Ca, and Mg, along with measurements of electrical conductivity and pH levels of the soil samples.