Journal article
Radionuclide migration and correlation in the soil–water–air environment at a radioactive waste storage site, Uzbekistan
- Institute of Nuclear Technologies, Samarkand State University, Samarkand, Uzbekistan
- Navoi State University of Mining and Technologies, Navoi, Uzbekistan
https://doi.org/10.1007/s10967-026-10977-y
Highlights
- Uranium in water of 20 monitoring wells: 2.32–12.25 Bq/L, mean 5.78 Bq/L (WHO guideline about 0.76 Bq/L).
- Radium-226 in the same water: 0.111–0.241 Bq/L, mean 0.177 Bq/L (guidance level 1 Bq/L).
- Radium-226 in soil: mean 5306.5 Bq/kg (114 to 18,670) at the site, 189.2 Bq/kg at 33 control points.
- Radium-226 by depth: 4676.2 Bq/kg at 0–5 cm, 5936.8 Bq/kg at 45–50 cm.
- Radon in soil air: 13.77 Bq/m³ at the surface, 16.79 Bq/m³ at 45–50 cm, 7.71 Bq/m³ at control sites.
- Gamma dose rate: 0.095–0.85 µSv/h at the site (mean 0.313), 0.065–0.145 µSv/h in settlements (mean 0.104).
Keywords
- natural radionuclides
- radiological assessment
- radionuclide migration
- radon exhalation
- technogenic radioactive waste
Summary
The storage facility for man-made radioactive waste covers about 7 km² in the Navoi region, about 1 km from the nearest settlement and 300 m from farmland. It consists mostly of crushed granitic rock, clay-rich hydrometallurgical residues and local sandy alluvium, and barriers of local soil divide it into eight sections. The climate is sharply continental and semi-arid, with a mean annual air temperature of about 15–16 °C and 200–230 mm of precipitation a year, falling mostly in winter and spring.
Soil was sampled at five points in each of the eight sections, at 0–5 cm and 45–50 cm, and at 33 control points around the site; radium-226, thorium-232 and potassium-40 were measured with an MKS-AT1315 gamma–beta spectrometer. Radon in soil air was measured with an AlphaRad Plus monitor at the surface and at 50 cm, and the gamma dose rate with a DKS-96 dosimeter at 20 stations 5 m from the enclosure and 1 m above the ground. Water from 20 monitoring wells was analysed for total uranium (Arsenazo III photometric method) and radium-226 (KAMERA-01, emanation method); the wells sit in the lower filtration zones and collect water that percolates through the waste.
Radium-226 in the soil of the site averaged 5306.5 Bq/kg (114 to 18,670 Bq/kg; coefficient of variation 103.1%), against 189.2 Bq/kg at the control points; thorium-232 averaged 112.4 Bq/kg and potassium-40 2239.9 Bq/kg (26.8 and 475.7 Bq/kg at the control points). Radium was higher at 45–50 cm than at the surface (5936.8 against 4676.2 Bq/kg; Wilcoxon p = 0.070), which the authors read as downward migration with water, while thorium hardly differed between the layers. Radon in soil air averaged 13.77 Bq/m³ at the surface and 16.79 Bq/m³ at 45–50 cm, against 7.71 Bq/m³ at the control sites, and followed the radium content (r ≈ 0.67–0.70; p < 0.01).
In the monitoring wells, total uranium was 2.32–12.25 Bq/L (mean 5.78 Bq/L), against about 0.76 Bq/L that corresponds to the WHO guideline of 30 µg/L, and radium-226 was 0.111–0.241 Bq/L (mean 0.177 Bq/L), below the guidance level of 1 Bq/L. Uranium and radium were not correlated (r ≈ 0.07), which the authors explain by uranium moving as dissolved complexes while radium is held back by ion exchange and sorption. The gamma dose rate at the site was 0.095–0.85 µSv/h (mean 0.313 µSv/h), about three times that in nearby settlements (0.065–0.145 µSv/h, mean 0.104 µSv/h). The authors propose seasonal sampling, a larger network of monitoring wells and continued radioecological monitoring.
How to cite
U. Haydarov, A. Muzafarov and S. Khasanov (2026). Radionuclide migration and correlation in the soil–water–air environment at a radioactive waste storage site, Uzbekistan. Journal of Radioanalytical and Nuclear Chemistry, vol. 335, no. 7, pp. 4677–4689. https://doi.org/10.1007/s10967-026-10977-y