4,700 meters below sea level: findings raise questions
A scientific expedition that returned in 2026 to the site of historical radioactive waste dumping in the northeastern Atlantic Ocean reached barrels at a depth of approximately 4,700 meters, discovering that some are in various stages of disintegration. Researchers collected water, sediment, and biological samples to determine the fate of the waste and its potential impact on the ecosystem.
A scientific expedition that returned in 2026 to the site of historical radioactive waste dumping in the northeastern Atlantic Ocean reached barrels at a depth of approximately 4,700 meters, discovering that some are in various stages of disintegration. Researchers collected water, sediment, and biological samples to determine the fate of the waste and its potential impact on the ecosystem.
Deep beneath the Atlantic Ocean lie unusual remnants of past European radioactive waste management: more than 200,000 barrels dumped over several decades. Each 200-liter barrel contained primarily low-level radioactive waste, often mixed with concrete or bitumen to ensure structural integrity during the descent.
According to data from the French National Center for Scientific Research (CNRS), the UK was responsible for dumping over 140,000 barrels, Belgium for about 55,000, with France also conducting such operations. Researchers emphasize that there is no evidence the barrels contained nuclear fuel or high-level, long-lived waste. Nevertheless, the prolonged presence of these containers on the seabed raises concerns regarding their condition and environmental impact.
In 2025, the NODSSUM project, led by CNRS in collaboration with other institutions, launched an expedition. An autonomous underwater vehicle, UlyX, was deployed to map the site. Over the course of a month, 3,355 barrels were located. Researchers collected approximately 5,000 liters of water, hundreds of seabed samples, and dozens of fish and crustacean specimens for analysis.
This survey covered only a small fraction of the 14,500 sq. km dumping zone; the vehicle mapped roughly 165 sq. km, or less than two percent of the area. Even within this limited scope, thousands of barrels were identified, and imagery confirmed that some are no longer intact.
In 2026, scientists returned using the manned submersible Nautile to conduct close-range inspections. Many barrels showed advanced corrosion, and in several locations, researchers observed material leaking from the containers onto the surrounding seabed.
The team selected five zones for in-depth analysis, collecting water, sediments, and biological samples. Nearby areas were also surveyed to serve as a baseline for comparing the local environment.
Tests identified signals of radioactive materials associated with the waste, including Cobalt-60 and Niobium-94. Cesium-137 and Americium-241 were also detected, though further investigation is required to distinguish them from residues of nuclear weapons testing or other incidents. Researchers stated that current on-site measurements do not indicate levels posing a significant safety risk to the teams or equipment. The critical question remains the long-term impact on the marine environment.
Scientists also observed an interesting phenomenon: sea anemones, sponges, and crustaceans are thriving on and around the barrels. This is likely not related to radioactivity; in an area characterized by soft sediments, the barrels provide a rare hard substrate for marine colonization. The current research focus is determining whether radioactive materials have migrated from the barrels into these organisms and, if so, in what quantities.
