Plans to dispose of radioactive nuclear waste beneath the seabed off the north-west coast of England risk seriously harming marine life including mammals such as dolphins and whales, experts have warned. Seismic surveys in the Irish Sea near Cumbria get under way on Saturday to explore whether the area is suitable for a proposed facility. The UK government is seeking a location for a deep underground repository to store the world’s largest stockpile of untreated nuclear waste. Officials have said that a decades-long accumulation of materials including more than 100 tonnes of plutonium – which could create thousands of nuclear bombs – cannot sustainably be stored above ground for ever and they are therefore searching for a site to “keep it safe and secure over the hundreds of thousands of years it will take for the radioactivity to naturally decay”. In 2019, radioactivity leaked into the soil beneath Sellafield, in Cumbria, which saw a serious leakage in the 1970s and was not built with decommissioning in mind. There are 20 surface facilities that store highly radioactive waste across the UK. About 750,000 cubic metres, equivalent to 70% of the volume of Wembley stadium, is earmarked for “geological disposal”. But impacts related to noise exposure from seismic gun blasts have been linked to vastly reduced sightings of whales, whose primary sense is acoustic. There is also concern over storing nuclear waste underwater, with just a handful of such sites globally. The Zoological Society of London’s cetacean strandings investigation programme manager, Rob Deaville, said that seismic blasts can cause habitat avoidance, risk excluding mammals from an area, and raise the risk of decompression sickness. “Potential impacts can also include direct physical effects ranging from temporary or permanent threshold shifts in hearing to direct blast trauma,” he told the Guardian. There are also concerns that the blasts may drown out mating calls and even cause deaths, after more than 800 dolphins washed ashore in Peru in 2012 after seismic tests. On the Cumbria survey, Deaville added that the area is a known habitat for porpoises, dolphins and other species. “Our teams are very much on standby, in the event we receive increased reports of live/dead strandings over this period.” Advertisement In a letter to campaigners shared with the Guardian, an official from the Marine Management Organisation, a public body, acknowledged “the potential disturbance to certain cetacean species” but noted that the plans were largely exempt from regulations. Critics also suggest it may be impossible to predict the consequences of storing heat-generating nuclear waste beneath the sea in perpetuity. The chair of Nuclear Free Local Authorities (NFLA), David Blackburn, also leader of the Green party group at Leeds city council, told the Guardian: “The waste would be left in situ for millennia and, no matter how effective the barriers, some of the radioactivity will eventually reach the surface. The rate at which radioactivity would leak from a [geological disposal facility (GDF)] can be poorly predicted and is likely to remain so for an indefinite period. “Rather than solving a problem for future generations, it could be leaving them a legacy of a nuclear waste dump gradually releasing radioactivity into the environment and cutting off their options for deciding how to deal with this waste.” The NFLA prefers the idea of a “near surface, near site storage of waste” to allow for monitoring and management, and action in the event of a leakage. “Further scientific research may yield advancements that could mean that radioactive waste can be treated such as to make it less toxic in a shorter time period,” Blackburn added. “Chucking it in a hole in the ground or under the seabed precludes this possibility.” However, experts have said there is international agreement on the benefits of disposing of radioactive waste in deep geological repositories, and that it is the most appropriate long-term solution. “This consensus is based on scientific and technical work that has been carried out over several decades, including extensive research, development and demonstration programmes,” said a 2013 paper. Chris Eldred, the senior project manager for geosphere characterisation at the government organisation Nuclear Waste Services, launched this year to help oversee the decommissioning, said: “A deep GDF will protect future generations from the risks of keeping hazardous radioactive waste in surface stores for thousands of years. It is one of the largest environmental protection projects in the UK. “To help us with this vital work, we will undertake surveys within English territorial waters to provide a better understanding of the deep geology beyond the coast, while doing everything we can to minimise any environmental impact. “These surveys will use sound waves, the same technology that’s routinely deployed worldwide in industries such as offshore wind, carbon capture and storage, and major infrastructure projects, and along the lines of that used in medical ultrasound imaging. The information we obtain from these surveys will enable us to better understand whether a location could host a GDF and in turn will help inform discussions with communities.”