By Dr Helen Rosenbaum, Research Coordinator for the Deep Sea Mining Campaign
30 June 2026 | View media release

Today we’re releasing a report I’ve been working on with some brilliant colleagues, and I want to explain why I think it matters.

For 15 years, the Deep Sea Mining Campaign has been raising the alarm about the risks of mining the deep ocean. We’ve highlighted the destruction of seafloor habitats, the risk of heavy metal toxicity, the threats to Pacific communities and fisheries. The science on those risks is growing and confirms those concerns.

But one risk has been a sleeper.  I was first alerted to the possibility of DSM-induced radiation ecotoxicity by a 2023 research paper (Volz et al.) that looked at health risks for workers handling nodules. Since then I’ve been struck by the absence of research into the risks of DSM-induced radiation toxicity in the marine environment itself.  Companies appear to either ignore the risk or actively dismiss it.  

Radioactivity is all around us. On land there are radioactive isotopes in vegetation, soil and rocks. In the ocean some of the places they accumulate are the seafloor massive sulphides of hydrothermal vents, the polymetallic nodules of the deep abyssal plains, and the sediment of the ocean floor. Because radioactive isotopes are safely bound up in mineral structures, marine life has successfully adapted to the ocean’s natural background levels of radiation. 

Deep sea mining would crush and fragment nodules and sulphide deposits, dispersing debris for extensive distances.  The outer layers of nodules (most likely to be disrupted) are particularly enriched in radioactive alpha particles. These have form as extremely dangerous wrecking balls for cells, protein and DNA. They can build up in tissues of marine life, and similarly to mercury, can amplify their way up food chains that eventually reach our plates.

But that’s not all, deep sea mining will also release heavy metals at the same time. We have no idea what the marine ecotoxicity of this toxic combo will be. 

But here’s what really stopped me in my tracks: there is not a single peer-reviewed study on how deep sea mining-induced radiation toxicity affects marine ecosystems. Not one. And there are no safety standards to protect deep-sea species from this kind of exposure, because the global regulatory framework for marine radiation protection is based on three organisms — a flatfish, a crab, and brown seaweed.  Gob-smacking isn’t it? 

I think about what Alanna Matamaru Smith of the Te Ipukarea Society in the Cook Islands said when she read this report:

“This report raises critical questions about the potential for ecotoxicity and biomagnification within marine food webs that are a staple food source for Pacific Island communities. It highlights exactly the type of issues that Pacific peoples and their leaders need hard data on, in order to make informed decisions about the future of our ocean resources.”

This report doesn’t attempt to have the answers but it certainly raises the question: What are the likely ecological risks and effects of radioactive isotopes released by mining polymetallic nodules and seafloor massive sulphides, particularly in relation to impacts on marine species, ecosystems, and food webs. 

Please read it and share it. And please join us in calling on the scientific community and regulatory authorities to urgently address these questions and governments to support a moratorium on DSM until science, not greed, informs decisions.

The ocean cannot wait.