Radioactive waste barrels, which have been lying on the seabed for decades, kilometers under the Atlantic Ocean, were closely monitored by scientists.
According to ScienceAlert, European countries dumped more than 200 thousand barrels of low-level radioactive waste into the depths of the Atlantic Ocean in the second half of the 20th century. It is stated that the total weight of the waste exceeds 150 thousand tons.
Most of the barrels were left hundreds of kilometers away from the shores and at depths of approximately 3 thousand to 5 thousand meters. The NODSSUM project of the French National Center for Scientific Research (CNRS) aims to reveal the current state of the waste and its possible effects on the deep-sea ecosystem by mapping these areas in detail.
Nuclear technology in the period when radioactive waste was released into the ocean; It was rapidly becoming widespread in energy, medicine, industry and scientific research. However, solutions in line with today's standards have not yet been developed for the long-term storage of the resulting radioactive waste.
Therefore, dumping low-level waste onto the deep ocean floor was used as a disposal method.
In the approach of the period, it was envisaged that the barrels would remain closed for a period long enough for the short-lived radioactive isotopes to decay, and any substances that might emerge later would be diluted by spreading over the large ocean volume.
But the waste did not only contain short-lived substances. It is stated that the barrels also contain radioactive substances such as cesium-137, plutonium isotopes and tritium, which can remain in the environment for a long time.
'THE FORGOTTEN CEMETERY' IS BEING RESEARCHED AGAIN
The exact location and physical condition of the barrels remained largely unclear for many years after the discharging of radioactive waste into the sea ended.
Scientists led by French nuclear engineer Patrick Chardon and marine geologist Javier Escartín launched the NODSSUM (Nuclear Ocean Dump Site Survey Monitoring) project to find answers to these questions.
Researchers from different disciplines such as nuclear physics, geology, oceanography, biology and marine chemistry work together in the project.
The first major field study of the research was carried out in June 2025 with the L'Atalante research ship.
Using the autonomous underwater vehicle called UlyX, scientists scanned the seafloor and imaged the areas where the barrels were located.
In a one-month study, the location of 3 thousand 355 barrels was determined and mapped. The researchers also collected nearly 5,000 liters of water samples, took 345 seafloor cores and began studying 34 samples of fish and crustaceans.
This research allowed scientists to determine which barrels to examine closely next.
THEY LANDED TO 4 THOUSAND 700 METERS
Researchers returned to the region in May 2026, this time with the Pourquoi Pas research ship.
The manned Nautile submarine, which can dive to a depth of 6 thousand meters, was used in the work.
According to ScienceAlert, researchers carried out 20 dives and had the opportunity to directly examine the barrels at depths above 4,700 meters. At the same time, samples of water, sediment and living things around the barrels were collected.
During the examination, it was seen that some barrels were severely corroded due to exposure to sea water for many years.
While substances were observed spreading from barrels to the surrounding sandy ground at some points, researchers also made measurements of radioactive isotopes in the region.
It was reported that especially cobalt-60 and niobium-94 signals were associated with the waste left, while cesium-137 and americium-241 levels were measured above the expected background values in the region.
However, these findings do not mean that there is harmful levels of radioactive accumulation in living things in the region. In order to determine this, laboratory analyzes of the collected samples must be completed.
BARRELS BECAME A HOME FOR SEA LIFE
One of the remarkable findings that scientists encountered during the research was that the barrels turned into artificial habitats for sea creatures over time.
Sea anemones, sponges and sea cucumbers settled on the barrels; Fish and various crustaceans were also observed to gather around these structures. It was stated that crabs were especially concentrated around the barrels.
This situation made one of the main questions of the research more important: Do the radioactive substances emitted from the barrels into the environment pass into the tissues of the creatures living there?
Nautile collected samples of sediment, water, microorganisms and other living things from the immediate surroundings of the barrels at five different points.
In order to make comparisons, the researchers also took samples from nearby rocky areas that were not affected by the barrels.
Laboratory analyzes aim to determine whether radioactive substances accumulate in marine organisms and, if so, whether this has a measurable effect on the local ecosystem.
Although initial measurements revealed that there were radioactive traces around the barrels, according to the data provided by ScienceAlert, levels that would pose a serious radiation protection problem for scientists working with the samples were not detected. No radioactive contamination was detected in Nautile or the scientific devices used.
