Abstract
An assessment was made of the activity concentrations of natural and artificial radionuclides in the soil–vegetation cover of the arid zone of Kazakhstan along the 65th and 75th meridians. The mean activity concentrations in soils were 580.7 Bq/ kg for ⁴⁰K, 34.8 Bq/kg for ²³²Th, 23.0 Bq/kg for ²²⁶Ra, and 16.9 Bq/kg for ¹³⁷Cs. In plants, the mean activity concentrations calculated from the quantitatively determined values were 489.2 Bq/kg for ⁴⁰K, 2.5 Bq/kg for ²³²Th, 14.3 Bq/kg for ²²⁶Ra, and 1.2 Bq/kg for ¹³⁷Cs. The activity concentration of ²⁴¹Am could not be quantified. The highest variability in concentration ratio (CR) values was observed for ¹³⁷Cs, whereas relatively greater uptake by plants was observed for ⁴⁰K and ²²⁶Ra. The estimated absorbed dose rate to plants ranged from 1.6 to 8.9 µGy/day along the 65th meridian and from 3.7 to 15.0 µGy/day along the 75th meridian. These values were substantially below the levels at which radiation effects in reference species are expected. The results obtained can be used as baseline characteristics for radiation monitoring, assessment of radionuclide dynamics, and radiation dose burdens on biota, as well as for subsequent monitoring of the radiological status of the study area.