Radioecological and plant response patterns under chronic radiation exposure at former nuclear test sites

Background: Atmospheric and underground nuclear weapons testing generated long-lasting radioactive contamination across multiple terrestrial and marine environments. Several former nuclear test sites still exhibit heterogeneous distributions of radionuclides in soils, groundwater, sediments, and biota decades after testing ceased. Objective: This review critically examines radionuclide persistence, environmental transfer processes, and reported ecological and plant-related responses across major historical nuclear test regions, including the Nevada Test Site, Semipalatinsk, the Marshall Islands and French Polynesia. Methods: A comparative literature-based analysis was conducted using radiological surveys, environmental monitoring reports, and peer-reviewed radioecological studies. The review evaluated contamination patterns, soil-to-biota transfer pathways, and documented ecological observations across chronically exposed environments. Results: Persistent contamination involving radionuclides such as 137Cs, 90Sr, plutonium isotopes, americium, and tritium remain documented at several former testing areas. Monitoring programs consistently report strong spatial heterogeneity influenced by local geology, hydrology, atmospheric transport, and resuspension processes. Although some studies describe altered ecological dynamics and physiological stress responses in exposed organisms, evidence for consistent long-term ecosystem-scale effects or adaptive biological responses remains limited and site-dependent. Interpretation is further complicated by heterogeneous dosimetry, limited longitudinal datasets, and multiple environmental confounding factors. Conclusions: Former nuclear test sites remain important environments for long-term radioecological investigation. Current evidence clearly supports persistent environmental contamination and ongoing radionuclide transfer processes, whereas broader ecological consequences remain incompletely resolved.