Radioactive Waste Dumped in Atlantic is Showing Signs Of Leakage

More than 150,000 tons of low-level radioactive waste were dumped in the Atlantic Ocean between 1949 and 1982, and scientists investigating the sites have found corroded barrels with radioactive material visibly escaping, Michelle Starr reported for ScienceAlert.

Researchers using a crewed submersible examined barrels of radioactive waste dumped in the Atlantic and found extensive corrosion and evidence that radioactive material had escaped.

More than 200,000 barrels of low-level radioactive waste were disposed of at sea, mostly at depths of about 3,000 to 5,000 meters (9,840 to 16,400 feet), according to ScienceAlert’s account of the research.

The waste originated from European nuclear, medical and industrial activities.

The recent investigation was conducted by NODSSUM, or Nuclear Ocean Dump Site Survey Monitoring, an interdisciplinary research project involving scientists studying the environmental effects of the historic dumping.

The first expedition, conducted in June 2025 aboard the research vessel L’Atalante, used an autonomous underwater vehicle to map and photograph the seafloor. Researchers located and mapped 3,355 barrels during that expedition.

In May 2026, researchers returned aboard the Pourquoi Pas? with the three-person Nautile submersible.

During more than 20 dives, the submersible descended to more than 4,700 meters to inspect the barrels and collect environmental samples.

Scientists found that many barrels were heavily corroded and degraded, with material visibly escaping onto the surrounding seafloor. Instruments detected radioactive isotopes including cobalt-60 and niobium-94 associated with the dumped waste.

Cesium-137 and americium-241 were also detected at levels above expected background from atmospheric nuclear testing and other sources.

Low-level radioactive waste does not mean non-hazardous waste.

Such material generally contains lower concentrations of long-lived radionuclides than higher-level radioactive waste, but some radionuclides can remain radioactive for decades, centuries or longer.

The barrels have also become part of the deep-sea ecosystem.

Researchers observed anemones, sponges, sea cucumbers, fish and crustaceans living around the containers.

Samples collected around and in contact with the barrels are being analyzed to determine whether radioactive material is accumulating in marine organisms.

The researchers have not concluded that the radioactive waste is causing widespread contamination or an immediate threat to marine life.

ScienceAlert reported that radiation levels detected around the barrels were not high enough to create major radiation-protection problems for scientists handling the samples, although further analysis is needed to determine the environmental consequences.