Mass Spectrometry Applications in Environmental Radionuclide Analysis

Mass spectrometry has become an indispensable tool for the detection, quantification and source attribution of radionuclides in environmental media. Techniques such as quadrupole‐based inductively coupled plasma mass spectrometry (ICP-MS), multi-collector ICP-MS (MC-ICP-MS) and accelerator mass spectrometry (AMS) offer unparalleled sensitivity and precision for both natural and anthropogenic radionuclides. These methods enable the determination of absolute concentrations at picogram per litre levels, as well as high‐precision isotopic ratio measurements that distinguish legacy fallout, routine releases and accidental emissions. Laser ablation coupling with MC-ICP-MS permits spatially resolved analysis of particles, sediments and biological tissues, reducing sample preparation and allowing in situ source identification. Advances in sample introduction, separation chemistry and data reduction algorithms have improved detection limits and reduced interferences, extending applications from cryospheric and marine tracers to terrestrial soils and biota. The integration of isotope dilution adds rigorous quantification and uncertainty estimation, while novel nuclear forensic fingerprints such as ^135Cs/^137Cs and ^233U/^236U ratios underpin refined environmental monitoring and forensic investigations. Collectively, these mass spectrometric approaches are driving global efforts in radiological assessment, environmental management and climate‐impact studies by providing robust data on radionuclide fate, transport and bioavailability.

Research from Nature Portfolio

High-precision MC-ICP-MS measurements of the ^233U/^236U ratio in seawater and sediment samples have demonstrated a new isotopic fingerprint capable of discriminating between civil nuclear industry discharges and weapons‐derived fallout. The distinct ratio difference of up to an order of magnitude provides a powerful tracer for tracking oceanic transport pathways and assessing routine and legacy emissions from nuclear power facilities.

In a foundational soil-core study downwind of a historic nuclear test site, mass spectrometric determination of plutonium isotopes (^239Pu, ^240Pu) and americium (^241Am) revealed heterogeneous fallout patterns and rapid vertical migration in the vadose zone. The use of MC-ICP-MS enabled source apportionment of regional versus global fallout, informing long-term radiological risk assessments and guiding remediation planning in affected regions.

Mass Spectrometry Applications in Environmental Radionuclide Analysis publication trend

The graph below shows the total number of articles in mass spectrometry applications in environmental radionuclide analysis across all publications each year (not limited to Nature Index journals).

Technical terms

ICP-MS: A technique in which a plasma source ionises a sample and a mass analyser separates ions by mass-to-charge ratio, enabling ultra‐trace elemental and isotopic measurements.

MC-ICP-MS: A variant of ICP-MS with multiple collectors that allows simultaneous detection of several isotopes, delivering high‐precision isotopic ratio data.

Isotope dilution mass spectrometry (IDMS): A quantification approach where a known amount of isotopically enriched spike is added to a sample to correct for losses and matrix effects, yielding accurate concentration measurements.

Laser ablation (LA): A sample introduction method that uses a focused laser beam to remove material from solid samples, which is then transported into the plasma for spatially resolved analysis.

Nuclear forensic fingerprint: A characteristic isotopic ratio (e.g. ^135Cs/^137Cs or ^233U/^236U) used to identify and distinguish radionuclide sources in environmental samples.

References

1. Disproportionately High Contributions of 60 Year Old Weapons-137Cs Explain the Persistence of Radioactive Contamination in Bavarian Wild Boars. Environmental Science and Technology (2023).
2. 233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout. Nature Communications (2020).
3. Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout. Scientific Reports (2015).
4. 135Cs/137Cs isotopic composition of environmental samples across Europe: Environmental transport and source term emission applications. Journal of Environmental Radioactivity (2015).
5. Evaluation strategies for isotope ratio measurements of single particles by LA-MC-ICPMS. Analytical and Bioanalytical Chemistry (2013).