Specific spatial distribution of 137Cs, 40K, 226Ra, 232Th in soils of the city of Polyarnyye Zori (Murmansk region)

Abstract

The article examines patterns of spatial distribution of 137Cs and natural radionuclides 226Ra, 232Th, 40K in the upper (0—5 cm) layer of soils in the main functional zones of the city of Polyarnye Zori. The analysis of the general gamma activity of the territory, using RS-700 mobile gamma spectrometric complex, showed, three local anomalies of increased gamma radiation, which were confined to high-rise buildings within the city. In undisturbed peat soils in the area of the Kola Nuclear Power Plant and in the area of urban forests and parks, the maximum specific activity of technogenic 137Cs was 29.5 and 28.8 Bq/kg, respectively. In other functional zones of the city, the activity of 137Cs was 5 times less. According to the results of the correlation analysis, the technogenic 137Cs has a moderate relationship (on the Chaddock scale) with the 45 and 500 µm fraction. 232Th has a high affinity with 226Ra, and 40K with 232Th, which are statistically significant results when taking P-Value into account. It can be assumed that natural radionuclides 232Th, 40K, 226Ra have a moderate association with the 1 mm fraction due to the presence of particles of this size in the upper soil layer. There is a moderate relationship between 232Th and 40K.