Radiological Assessment of Natural Radionuclides and Soil-to-Plant Transfer Factor of Cowpea Cultivated on a Mining Impacted Soil for the Tropical Ecosystem of Nigeria

Abstract

Cowpea is one of the critical foods that contributes significantly to the Nigerian food basket, as Nigeria is the largest producer and consumer of cowpea worldwide. In this work, the soil-to-plant transfer factor of 40K, 238U, and 232Th for cowpea plant compartments (root, stem, leaf, and seed) were evaluated. Three planting soil groups were formulated for pot experiments using tailings from an abandoned tin mining site and virgin soil from an uncultivated area. Gamma spectrometry was utilized in measuring the activity concentrations of the radionuclides in the soil groups and plant compartments.  The geometric mean (GM) of the TF of 40K, 238U, and 232Th for the cowpea plant compartments ranged from 0.05 (seed samples) to 9.67 (leaf samples), BDL (stem, leaf, and root samples) to 2.34 (root samples) and 0.05 (stem samples) to 9.73 (leaf samples). Significance differences were observed in the mean TFs of the radionuclides across the soil groups. The mean committed effective doses are below the UNSCEAR recommended limit for the public.