RADIOECOLOGICAL STUDIES IN URBAN SOIL OF VANADZOR

Abstract

The work summarizes the results of radioecological studies of soils implemented in one of the largest cities of Armenia: the city of Vanadzor. Gamma spectrometric and iMatic gas-less counting systems (CANBERRA) were applied to determine the specific activities of natural radionuclides (⁴⁰K, ²²⁶Ra, ²³²Th) and gross α/β activities, respectively. Radiological indices and excess lifetime cancer risk were calculated according to the methodology of the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Statistically significant correlation was found between the activities of ²³²Th and ⁴⁰K. The relatively high values of gross α/β activities were found in the northern and western parts of the city. In the case of natural radionuclides, the average (17.08 Bq/kg) and geochemical background (16.88 Bq/kg) of ²²⁶Ra and do not exceed the UNSCEAR value for the soil of Armenia (46 Bq/kg). The highest activities of ²²⁶Ra were found mainly in the northern part and city center. The average activity of ²³²Th (29.66 Bq/kg) was close to UNSCEAR average value (30 Bq/kg) and the background (37.03 Bq/kg) slightly exceeds. In most parts of the city, ²³²Th does not exceed the background value. For ⁴⁰K the average activity (390.44 Bq/kg) was found to be higher than UNSCEAR value. The background value (469.0 Bq/kg) also exceeds the UNSCEAR average, however, the activities of all investigated radionuclides are within the ranges. ⁴⁰K also does not exceed the background in most of the city. Radionuclide-associated radiological hazards, in particular, absorbed gamma dose rate, annual effective dose equivalent, radium equivalent activity, and cancer risk do not exceed the reference values.