Radioactive fallout legacy of nuclear tests in soils of the Southern Hemisphere
Abstract
Fallout radionuclide (FRN) archived in soils are key tracers of soil redistribution, sediment dynamics, and associated carbon fluxes, yet their global application is limited by poorly constrained baselines in the Southern Hemisphere. Here, we present the first hemisphere-scale baseline and uncertainty maps of ¹³⁷ Cs and ²³⁹⁺²⁴⁰ Pu soil inventories. Predictions exhibited lower spatial variability and relative uncertaintyfor ¹³⁷ Cs across most landscapes, whereas ²³⁹⁺²⁴⁰ Pu showed greater spatial variability and larger relative uncertainty. The reconstructed inventories revealed strong latitudinal and topographic gradients, with the highest predicted fallout occurring in tropical and mountainous regions. We further show, under a standardized hypothetical 50% inventory-loss scenario, that uncertainty in low-inventory regions can propagate nonlinearly into soil erosion and carbon-budget estimates, producing carbon budget biases of up to 19.8 t C ha ⁻¹ . These findings provide a new benchmark for Southern Hemisphere fallout radionuclide applications and a scalable framework for integrating spatial uncertainty into sediment tracing, soil degradation assessment, and carbon cycle studies.
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BibTeX
@article{avcıoglu2026radioactive,
title = {{Radioactive fallout legacy of nuclear tests in soils of the Southern Hemisphere}},
author = {Aydoğan Avcıoğlu and Gerald Dicen and Surya Gupta and Christine Alewell and Olivier Evrard and Pierre Sabatier and Hélène Angot and Rosalie Vandromme and Olivier Cerdan and Katrin Meusburger},
journal = {Communications Earth \& Environment},
year = {2026},
month = nov,
doi = {10.1038/s43247-026-04218-z},
url = {https://www.nature.com/articles/s43247-026-04218-z},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Radioactive fallout legacy of nuclear tests in soils of the Southern Hemisphere
AU - Aydoğan Avcıoğlu
AU - Gerald Dicen
AU - Surya Gupta
AU - Christine Alewell
AU - Olivier Evrard
AU - Pierre Sabatier
AU - Hélène Angot
AU - Rosalie Vandromme
AU - Olivier Cerdan
AU - Katrin Meusburger
PY - 2026
DA - 2026/11/07
JO - Communications Earth & Environment
DO - 10.1038/s43247-026-04218-z
UR - https://www.nature.com/articles/s43247-026-04218-z
AB - Fallout radionuclide (FRN) archived in soils are key tracers of soil redistribution, sediment dynamics, and associated carbon fluxes, yet their global application is limited by poorly constrained baselines in the Southern Hemisphere. Here, we present the first hemisphere-scale baseline and uncertainty maps of ¹³⁷ Cs and ²³⁹⁺²⁴⁰ Pu soil inventories. Predictions exhibited lower spatial variability and relative uncertaintyfor ¹³⁷ Cs across most landscapes, whereas ²³⁹⁺²⁴⁰ Pu showed greater spatial variability and larger relative uncertainty. The reconstructed inventories revealed strong latitudinal and topographic gradients, with the highest predicted fallout occurring in tropical and mountainous regions. We further show, under a standardized hypothetical 50% inventory-loss scenario, that uncertainty in low-inventory regions can propagate nonlinearly into soil erosion and carbon-budget estimates, producing carbon budget biases of up to 19.8 t C ha ⁻¹ . These findings provide a new benchmark for Southern Hemisphere fallout radionuclide applications and a scalable framework for integrating spatial uncertainty into sediment tracing, soil degradation assessment, and carbon cycle studies.
SN - 2662-4435
ER -