Activity Concentration of Natural Radionuclides in Agricultural Soil, Fertilizer, their Transfer to Some Commonly Used Cereal Types, and Associated Health Hazards, Holeta, Ethiopia

Abstract

Purpose: In the current study, the concentrations of natural radionuclides in samples of agricultural soil, fertilizer and cereal types commonly used in Ethiopia were estimated. Besides, the transfer of natural radionuclides (U-238, Th-232, and K-40) from agricultural soil to identified cereal types were computed. Materials and Methods: Gamma-ray spectrometry coupled to HPGe detector was used for the estimation of activity concentrations in soil, fertilizer and identified cereal types. Normalized relations of measured activity values with constant paremeters, given by UNSCEAR and WHO were used to investigate the related radiological parameters and radiation indices. Results and Discussion: The average activity concentrations in samples of agricultural soil are 46.44±6.68 Bq.kg-1, 94.66±13.98 Bq.kg-1, and 368.88±51.76 Bq.kg-1 and in fertilizer samples 38.5±4.15 Bq.kg-1, 87.6±9.36 Bq.kg-1, and 334.0±35.58 Bq.kg-1 for U-238, Th-232, and K-40 respectively. In the same way, the activity concentrations of these radionuclides was measured in identified cereal types. The related radiological parameters and radiation indices in the samples of soil and fertilizer were figured and compared with the prescribed limits set by the concerned committees (UNSCEAR, WHO). Conclusions: According to this study, U-238 and Th-232 activity concentrations in samples of soil and fertilizer are above the prescribed limits, where activities in the fertilizer are additive to the soil and in K-40 is within the safety limit. The gamma radiation exposure from the soil samples and annual effective dose via ingestion of cereals can create a risk to the public, where other investigated indices are within the safety limit prescribed by UNSEAR and WHO reports.