Assessing Radioactivity in Agricultural Soils: Spatial Distribution Patterns, Area-Specific Influences, and Radiological Hazard

Abstract

Natural and artificial radioactivity of agricultural soils poses significant environmental and health risks, necessitating detailed spatial analysis and hazard assessment. This study examines the spatial distribution of natural and artificial radionuclides (NOR and Cs-137), gross α and β activity, and in situ dose rates in agricultural soils through statistical and geostatistical techniques. NOR, Cs-137, and gross β activity exhibited high values and outliers, highlighting distinct distribution patterns. The Cs-137-altitude regression model consistently increased Cs-137 by 0.03 Bq/kg/m in height. Spatial distribution of natural radioactivity implies geology as a primary factor influencing the NOR distribution. However, analysis of spatial clusters and outliers unveiled geochemical variability for Ra-226 and Th-232, while the K-40 distribution appeared spatially random, potentially linked to agricultural activity. Additionally, a significant disparity in the distribution of K-40 by land use was identified, potentially attributable to potassium fertilizer application. Despite variability, average NOR values (394 Bq/kg for K-40, 22.5 Bq/kg for Ra-226, and 24.8 Bq/kg for Th-232) fall within UNSCEAR ranges. Gamma-emitting radionuclide-induced doses and risk primarily impacted nonresidential areas. These findings can be used in land use decisions, guide the development of contamination mitigation strategies to ensure safe agricultural practices, and help predict areas at risk of higher contamination for targeted remediation efforts.