Transfer Factor of Radionuclides from Soil to Rice around Solid Mineral Mining Area in Ikwo Local Government Area of Ebonyi State, Nigeria

Mgbeokwere C

Published on: 2023-10-28

Abstract

Contamination of land could occur during the extraction and handling of materials containing high levels of naturally occurring radionuclide materials. Ingestion of food crops grown in a contaminated soil can be a source of human exposure to radioactive elements such as ²³⁸U, ²³²Th and ⁴⁰K which can lead to internal radiation doses. To obtain the TFs of ²³⁸U, ²³²Th and ⁴⁰K from agricultural farm soils to food crops, analysis of the radionuclide levels in both food crops and the associated farm soils were carried out via gamma-ray spectrometry. The average specific activity concentration of ²³⁸U, ²³²Th and ⁴⁰K in soil samples in the five farms were 9.26 BqKg^-1, 8.81 BqKg^-1 and 170.53 BqKg^-1 respectively. The average specific activity concentration of ²³⁸U, ²³²Th and ⁴⁰K in rice samples in the five farms were 5.86 BqKg^-1, 7.08 BqKg^-1 and 113.77 BqKg^-1 respectively. These results are below the [13] values of 400 BqKg^-1 Potassium, 35 BqKg^-1 Uranium and 30 BqKg^-1 Thorium. The average radium equivalent (in Bqkg^-1) estimated from the activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K in soil and rice samples ranges from 14.92 to 42.12 BqKg^-1 which were lower than the recommended value of 370 Bqkg^-1 [17]. The radiological transfer factor for ⁴⁰K ranges from (8.0 to 1.84) with an average value of 1.04. The radiological transfer factor of ²³⁸U ranges from (0.00 to 4.13) with an average value of 1.36 and TF of ²³²Th ranges from (0.00 to 2.43) with an average value of 0.85. This study transfer factor values are higher than the world permissive values of 1.00, 0.03 and 0.05 for ⁴⁰K, ²³⁸U and ²³²Th respectively. The results of this work show that long term consumption of rice from the study area may be detrimental to human health.