Assessment of Radiation Risks and Statistical Evaluation of Natural Radioactivity in Typical Fertilizer Types

Abstract

Purpose: The application of fertilizers raises concerns regarding their potential to increase natural soil radioactivity, attributed to radioactive elements found in specific types of fertilizers. The purpose of this work is to assess the natural radioactivity levels of different fertilizers by measuring the concentrations of radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K and other risk factors using a High-Purity Germanium (HPGe) detector with 50% relative efficiency, and to complete this assessment, eight fertilizer samples were collected and were dried, crushed, and sieved for homogenization.
Materials and Methods: They were then sealed in Marinelli beakers (type 533N) and were stored for gamma spectroscopy analysis. Furthermore, SPSS software was employed for data analysis, applying cluster analysis, Pearson correlation, basic statistical evaluations, and multivariate statistical techniques to explore relationships among the radionuclides and hazard indices.
Results: To assess potential radiological health risks, several radiation hazard indices were calculated and ranging between (119.39-17.59) Bq/Kg for the Radium Equivalent Activity (Raeq), (0.32- 0.05) for External Hazard Index (Hex), (0.42- 0.06) for Internal Hazard Index (Hin), (0.07-0.01) mSv/year for Annual Effective Dose Equivalent (AEDE), (57.07- 8.71) nGy/h for D, (0.89- 0.13) for Gamma Index (Iγ), (0.40- 0.01) mSv/year for Annual Gonadal Dose Equivalent (AGDE), ((0.24- 0.06) 10⁻³ for Excess Lifetime Cancer Risk (ELCR),(56.98- 7.85) W/kg for Radioactive Heat Production Rate (RHP). These levels stay within the specified and appropriate boundaries, except the AGDE risk for the Perlite Saudi. The results also indicated the levels in Bq/kg of measured radionuclides for all samples ranging between (54.3±28.4- 6.2±2.3) for ²²⁶Ra, (29.2±6.4- 2.1±0.3) for ²³²Th, and (551.2±38.1- 99.3±11.6) for ⁴⁰K.
Conclusion: The results indicate that the analyzed fertilizers do not present significant radiological health risks to humans or the environment, with radiation hazard factor levels remaining below the global average limits set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).