Transfer from soil to grass and statistical analysis of naturally occurring radionuclides in soil from phosphate mining and processing sites in Maritime Region of Togo

Abstract

Natural radionuclides activity concentrations of 226 Ra, 228 Ra, and 40 K in soil and grass samples, statistical analysis of these radionuclides and transfer factors (TFs) from soil to the grass were carried out from phosphate mining and processing sites in southern areas of Togo using gamma-ray spectrometry-based High Purity Germanium (HPGe) detector. The average activity concentrations of 226 Ra, 228 Ra, and 40 K were found within the range usually measured worldwide. Statistical analysis was done by investigating the skewness, the kurtosis, and the density distribution of radionuclides in the study areas. Both skewness and kurtosis displayed that the activity concentrations of soil and grass samples in the dischargement waste site (Kpémé) and mining site (Hahotoé) exhibited slightly positively skewed, negatively skewed, leptokurtic, and platykurtic distributions. The TFs for 226 Ra, 228 Ra, and 40 K from dischargement waste soil to grass were evaluated. The average transfer factors of 226 Ra, 228 Ra, and 40 K in the phosphate processing area were found to be 0.16, 0.32, and 8.42, respectively. 226 Ra and 228 Ra TFs values were found to within the limit of worldwide measure values while that of 40 K was to be larger than the values measured in other countries. The average TF value of 8.42 for 40 K was 8 times higher than the average value of unity, showing its large intake by vegetables. The high TFs for 40 K could be explained by the extensive application of phosphate fertilizers to soils when growing vegetables.

Distributions and Risk Assessment of the Natural Radionuclides in the Soil of Shoubra El Kheima, South Nile Delta, Egypt

“…These radioactive elements naturally make their way into the soil, surface water, and groundwater through different earth surface processes [2,6]. Their concentrations increase above normal levels in association with anthropogenic activities, such as the testing of nuclear weapons [2], mining, the production of industrial minerals and materials [7][8][9][10][11], fossil fuel production and combustion [12][13][14], and the use of phosphate and potassium sulfate fertilizers [15][16][17].…”