Increasing the digital data flow capacity between Romania and the Republic of Moldova regarding the monitoring of soil radioactivity and radon

Acronym: DIGNORM

21ROMD PN-IV-P8-8.3-ROMD-2023-0241

Project 21ROMD

Funded by The Executive Unit for Financing Higher Education, Research, Development, and Innovation (UEFISCDI)
Programme PNCDI IV - Program 5.8 - European and International Cooperation
Subprogramme 5.8.3 Bilateral/Multilateral
Funding 100.000 euro
Period 2024 - 2026

Soil plays an important role in agricultural policy, environmental protection, and climate change. However, in recent decades, human activities have become one of the major sources of soil pollution. Furthermore, soil degradation processes such as erosion, contamination, and loss of soil biodiversity continue to pose major threats to soil health across Europe. To consistently address these types of problems, to implement an effective monitoring system, and to produce reliable data, this project aims to apply nuclear techniques, such as in situ and laboratory gamma spectrometry, for monitoring soil radioactivity. Using the data generated by these techniques, soil mapping can be performed to meet the needs of agricultural and environmental protection policies.

Research Summary

Geostatistical Mapping and Integrated Radiological Assessment

This project presents a geostatistical mapping and integrated radiological assessment of naturally occurring radionuclides (NORM) in agricultural and grassland soils from regions of eastern Romania and Republic of Moldova, with complementary evaluation of indoor radon exposure.

The main objective was to characterize the spatial distribution of natural radionuclides, assess associated radiological hazards, and investigate the relationship between soil radioactivity and indoor 222Rn concentrations in order to support environmental radiation protection and public health risk assessment.

The study included:

  • 127 soil samples collected from different land-use categories;
  • Laboratory-based gamma-ray spectrometry for determining the activity concentrations of 238U/226Ra, 232Th, 40K, and 137Cs;
  • The same number of in situ gamma dose rate measurements;
  • Uranium concentration measurements using portable gamma spectrometry systems;
  • Statistical analyses, including descriptive distribution analysis and regression modeling;
  • Spatial interpolation using Geographic Information System (GIS) tools and Ordinary Kriging.

Main results:

The results showed that radionuclide activity concentrations varied considerably across the study area, between 217 Bq/kg and 1158 Bq/kg for the total, primarily as a function of geological and pedological conditions, with secondary influence from land use.

Among the investigated radionuclides, 226Ra and 232Th exhibited the greatest spatial heterogeneity, whereas 40K showed relatively stable distributions. All calculated radiological hazard indices remained below internationally accepted safety thresholds, indicating no significant external radiological risk.

A strong correlation was observed between 238U and 226Ra, confirming their geochemical linkage. In contrast, indoor radon showed only weak correlation with soil 226Ra and a moderate relationship with soil uranium concentration, demonstrating that geological source terms alone are insufficient to explain indoor radon variability.

Spatial interpolation identified localized hotspots of enhanced radionuclide concentrations and several areas with indoor radon levels exceeding internationally recommended reference values.

Conclusion

The project demonstrates that integrated environmental radioactivity measurements combined with statistical and geospatial analysis provide a robust framework for regional radiological risk assessment. While soil radionuclide concentrations are valuable indicators of regional radon potential, direct indoor radon monitoring remains essential for accurate exposure evaluation and effective radiation protection strategies.