Abstract \\r\\n1. Background and aims. This work is aimed at determining the concentration and intensity of migration of natural radionuclides in soil-plant cover of the North-Western Precaspian region, prone to desertification. \\r\\n2. Methods The total contents of 238U and 232Th in the soils and ash the plants was determined spectrophotometrically with arsenazo-III. Methods include: the bulk composition of 238U and 232Th in the soils and ash the plants was determined by means decomposition HF acid, later pre-processing of soil and ash the plants samples in an 8-12N HCl and HNO3. \\r\\n3. Results ?limatic conditions (amount and intensity of rainfall, temperature and relative humidity, etc.) and soil conditions (humus, pH, carbonates, sulphates, the degree and type of salinization, etc.), wind erosion, deflation, increased migration and distribution of salts, high pasture load, topography increase the content of easily soluble compounds of uranium and thorium in light-chestnut soils and saline soils, on the one hand due to the migration of radionuclides in the soil profile, with different sedimentation in conditions of aridization and desertification.\\r\\n4. Conclusions The concentration of 238U in light-chestnut soils and typical saline of the North-Western Precaspian region above Clarke values more than 1.5 times, and 232Th in these soils more than 2 times. 226Ra and 40K in the soils vary within Clarke values. Values 232Th/238U relations in soils is not consistent with the values 232Th/238U in the crust and soils, not subject to anthropogenic influences. Violation of radioactive equilibrium in soils due to the high content of thorium. The plants: Artemisia arenaria DC., Atriplex tatarica, Typha angustifolia L., Limonium meyeri, Artemisia lerchiana Kochia prostrata, Bassia hirsuta, Artemisia taurica Willd can be used as bioindicators for environmental radiation monitoring.

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