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The Deep Sea Conservation Coalition (DSCC) renewed its calls for a moratorium on deep-sea mining after a scientific paper was released warning of “alarmingly high” concentrations of radiation in polymetallic nodules which substantially exceed safe international levels. Radioactive particles include Ra-226, Ra-222, Th-230, and Pa-231 (radium-226, radon-222, thorium-230, and protactinium-231).

The paper published on 17 May explained that, if deep-sea mining were to commence, during processing, nodules would be crushed into smaller pieces. This would likely distribute a fraction of nodule particles into the air, which could be inhaled or ingested by humans during the operation. Inhaled fine particles, which are likely to remain in the lungs, have the potential to pose a radiological hazard to human health. The paper warns against inhalation or ingestion of nodule particles, the inhalation of radon gas in enclosed spaces, and the potential concentration of some radioisotopes during nodule processing.

The paper also finds that residual products from the mining slurry (a mixture of seawater, sediment and nodule fines) would be released back into the ocean as a discharge plume, where radioactive particles could be ingested by marine organisms. They may thus enter the food chain, introducing toxins up through the food web, and ultimately be ingested by people.Furthermore, the potential impacts on marine life through exposure to radiation have yet to be fully studied.

The authors conclude that “The new radioisotope dataset presented in this study validates the alarmingly high activity concentrations published in historic studies and vice versa. These values exceed current national and international exemption levels by up to three orders of magnitude. This exceedance of the exemption limits has, to our knowledge, not yet been taken into consideration for the legal framework of mining operations.”

DSCC lawyer Duncan Currie said that: “The prospect of sediment being pumped 1,200 metres below the surface of the ocean as a nearly continuous plume is already known to threaten marine life. This new information that the resulting sediment may be radioactive reinforces the concerns already expressed by numerous countries and stakeholders. Radiation has not even been considered in the regulations to date, yet the International Seabed Authority is being encouraged to adopt regulations by July.”

Sofia Tsenikli, the DSCC’s Deep-Sea Mining Moratorium Campaign Lead said: “This new scientific study, which demonstrates the high radioactivity of these deep-sea minerals, is a clear illustration of how much we still don’t know about the deep sea and the risks and impacts of deep-sea mining on humans and marine life. This is why across the world, scientists, Indigenous leaders, businesses, civil society and a growing number of countries are urging a pause on deep-sea mining before irreversible damage is caused to people and the planet. The time for a moratorium is now.”

“Across Oceania Indigenous people still suffer from the toxic legacy of nuclear weapons,” said Hinano Murphy, Culture Director for the Tetiaroa Society in French Polynesia. “It is time for humanity to recognize and respect the resilience of Indigenous peoples, and to work towards a future where such atrocities are never repeated. Mining the depths of our sacred ocean was already impossible for us to accept for cultural and spiritual reasons. But this study adds to the mounting evidence that deep-sea mining would irreparably damage the physical and biological processes of the ocean and its creatures.”

Murphy added, “We cannot imagine how anyone can condone any further damage to our ocean and the people that depend on it for their livelihood and as a foundation of their traditional cultures. This new evidence for potential nuclear contamination must surely lead to a ban on mining the ocean.”


Notes: The paper was published in Scientific Reports by Jessica B. Volz, Walter Geibert, Dennis Köhler, Michiel M. Rutgers van der Loeff and Sabine Kasten. Alpha radiation from polymetallic nodules and potential health risks from deep-sea mining. Sci Rep 13, 7985 (2023).

Radium-226 has a half-life of 1,600 years; thorium-230 has a half-life of 75,380 years and protactinium-231 has a half-life of 33,000 years. A half-life is the length of time it takes for half of the radioactive atoms of a specific radionuclide to decay.