RADIOECOLOGICAL ASSESSMENT AND GAMMA RADIATION LEVELS OF THE SOIL COVER IN KOSTANAY REGION

Abstract

The relevance of this study is driven by the lack of comprehensive data regarding the levels of natural and anthropogenic radionuclides in the soils of the Kostanay region. This region is characterized by significant mineral deposits and serves as one of Kazakhstan's primary grain-producing areas. Such dual anthropogenic pressure facilitates the redistribution and potential accumulation of both naturally occurring radioactive materials and technogenic radionuclides within the soil cover. Radionuclide measurements were conducted using a gamma-radiometer (RKG-AT 1320C). The specific activities of ⁴⁰K, ²²⁶Ra, ²³²Th, ¹³⁷Cs, and ¹³⁴Cs were determined. The study established that the mean specific activities of ⁴⁰K, ²²⁶Ra, and ²³²Th are within or below the global average values reported by UNSCEAR. Furthermore, all calculated values for the effective specific activity (Aeff) comply with Class I radiation safety standards (NRB-99). These findings indicate a favorable radiological environment and a low level of potential risk. The concentrations of technogenic ¹³⁷Cs, with the exception of isolated anomalies, do not exceed regulatory limits. Specific localized features: including elevated ⁴⁰K levels in the lower horizons of the Yubileinoye site, a ²²⁶Ra anomaly at the Moskovsky site, and the atypical deep-seated distribution of ¹³⁷Cs at the Amankaragay site, are of significant scientific interest and necessitate further investigation to determine their genesis. It is recommended to implement periodic monitoring at sites with identified anomalies and to expand research efforts to territories adjacent to the region’s mining facilities. The data obtained constitute the first systematic radioecological database for agricultural soils in the Kostanay region and may serve as reference values for the development of regional radioecological monitoring programs.