Natural Radioactivity Assessment in Environmental Systems

Natural radioactivity arises from primordial radionuclides such as uranium-238, thorium-232 and potassium-40 present in rocks, soils, waters and biota. Assessment of environmental radioactivity combines field sampling, laboratory spectroscopy and dose modelling to quantify activity concentrations, external and internal exposure pathways, and potential health risks. Gamma-ray spectrometry, often with high-purity germanium detectors, provides precise measurements of radionuclide activity in soils, sediments, building materials and foodstuffs. Derived indices – including absorbed dose rates, radium equivalent activity and annual effective dose – inform regulatory limits and guide remediation, land-use planning and public communication. Recent advances have focused on harmonising data collection protocols, integrating multivariate statistical analyses to identify key risk drivers, and refining soil-to-plant transfer factors to improve dietary exposure estimates. Such work underpins global frameworks for managing naturally occurring radioactive materials (NORM), enhances comparability across regions and supports evidence-based decision-making in environmental protection and public health.

Research from Nature Portfolio

A foundational study investigated the distribution of uranium-238, thorium-232 and potassium-40 in coastal soils of an industrially influenced region. Gamma-ray spectrometry revealed spatial variations in radionuclide activities, with radium equivalent activities ranging from moderate to elevated values relative to global averages. The work quantified mean ambient gamma dose rates and annual effective doses experienced by local populations, highlighting soils with the highest potential for long-term exposure. By estimating radiological hazard indices – including internal and external hazard indices – this research provided a benchmark dataset for regions where phosphate-rich sediments influence natural radioactivity, and established comparable methodologies for subsequent soil mapping and risk assessment studies.

Natural Radioactivity Assessment in Environmental Systems publication trend

The graph below shows the total number of articles in natural radioactivity assessment in environmental systems across all publications each year (not limited to Nature Index journals).

Technical terms

Naturally occurring radioactive materials (NORM): Materials containing natural radionuclides that contribute to background radiation in environmental media.

Radionuclide: An atom with an unstable nucleus that emits ionising radiation during decay, critical for quantifying environmental radioactivity.

Gamma-ray spectrometry: A technique using detectors to measure energy spectra of emitted gamma photons and determine activity concentrations of radionuclides.

Radium equivalent activity (Ra_eq): A consolidated index combining the activities of 226Ra, 232Th and 40K to evaluate overall radiological hazard of a material.

Soil-to-plant transfer factor: The ratio of radionuclide concentration in plant tissue to that in the corresponding soil, indicating uptake efficiency and dietary exposure potential.

References

1. Tools for harmonized data collection at exposure situations with naturally occurring radioactive materials (NORM). Environment International (2023).
2. Assessment of Natural Radioactivity Levels and Potential Radiological Risks of Common Building Materials Used in Bangladeshi Dwellings. PLOS ONE (2015).
3. Natural radioactivity and radiological risks of common building materials used in Semnan Province dwellings, Iran. Environmental Science and Pollution Research (2021).