Modeling the impact of extreme weather events and future climate on the radiologically contaminated sites of Enewetak Atoll

Journal Article · Wed Jan 15 00:00:00 EST 2025 · Scientific Reports

DOI:https://doi.org/10.1038/s41598-025-85849-8· OSTI ID:2566043

Premathilake, Lakshitha ^[1]; Ghosh, Saikat ^[1]; Prasad, Rajiv ^[1]; Taraphdar, Sourav ^[1]; Wang, Taiping ^[1]; Khangaonkar, Tarang ^[1]; Napier, Bruce ^[1]; Ikenberry, Tracy ^[1]; Leung, Lai-yung ^[1]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Enewetak Atoll underwent 43 historical nuclear tests from 1948 to 1958, including the first hydrogen bomb test, resulting in a substantial nuclear material fallout contaminating the Atoll and the lagoon waters. The radionuclide fallout material deposited in lagoon sediments and land soil will remain for decades to come. With intensifying climate and extreme weather events, the possibility of redistribution of deposited radionuclide material has become a great concern. This study uses a numerical modeling approach to estimate the potential elevated radionuclide concentrations that can be distributed during storm events under current and future climates. We simulated three historical storm scenarios that are most likely to impact Atoll’s environment and remobilize the radionuclide-bound sediments. WRF-ARW was used to reconstruct these storm scenarios under current year (2015) and future year (2090) climates. Storm-induced ocean hydrodynamics conditions were generated using FVCOM. FVCOM-ICM was externally coupled to simulate the fate and transport of radionuclides. Given that the ²³⁹Pu is the largest inventory of the lagoon and Atoll islands, the model results show the highest average ²³⁹Pu concentration that an island may be exposed to is 3.25E-4 Bq/m³ (becquerel per cubic meters), which is an increase of 84 times the average baseline/existing ²³⁹Pu concentration without the storm conditions. The overall increase in ²³⁹Pu average over all the islands of Atoll is about 20 folds relative to the baseline concentration. Despite the high relative increase ratios, the significantly low activity concentrations may not pose an immediate exposure risk. However, due to the limitations of the study and uncertainties/biases in the historical data used, further research supported by field surveys to better characterize the current contamination level may be needed to make more accurate predictions.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Environmental Management (EM)
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 2566043
• Report Number(s): PNNL-SA--203942
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Journal Issue: 1 Vol. 15; ISSN 2045-2322
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Extreme Weather Event Impacts
climate change impacts
contamination
radionuclide transport