Japan releases nuclear wastewater into the Pacific. How worried should we be?

The plan to gradually discharge more than a million tons of treated water from the crippled Fukushima nuclear plant has deeply divided nations and scientists.

Japan has started releasing wastewater into the ocean. But this isn’t the kind of wastewater that flows from city streets into stormwater drains. It’s treated nuclear wastewater used to cool damaged reactors at the Fukushima Daiichi nuclear power plant, stricken by an earthquake over a decade ago.

Japan claims that the wastewater, containing a radioactive isotope called tritium and possibly other radioactive traces, will be safe. Neighboring countries and other experts say it poses an environmental threat that will last generations and may affect ecosystems all the way to North America. Who is right?

Following a 9.1-magnitude quake off the east coast of Japan's main island on March 11, 2011, two tsunami waves slammed into the nuclear plant. As three of its reactors melted down, operators began pumping seawater into them to cool melted fuel. More than 12 years later, the ongoing cooling process produces more than 130 tons of contaminated water daily.

Since the accident, over 1.3 million tons of nuclear wastewater have been collected, treated, and stored in a tank farm at the plant. That storage space is about to run out, the Japanese government says, leaving no choice other than to begin dispensing the wastewater into the Pacific.

Japan’s discharge plan involves incrementally releasing it over the next three decades, although some experts say it could take longer, given the amount still being produced. While the International Atomic Energy Agency (IAEA)—the UN’s nuclear watchdog—assesses the plan’s safety, some of Japan’s neighbors are criticizing it as unilateral and dangerous. A senior Chinese official recently called it a risk "to all mankind” and accused Japan of using the Pacific as a “sewer.” The head of the Pacific Islands Forum, an organization representing 18 island nations (some already traumatized by decades of nuclear testing in the region) dubbed it a Pandora’s box. On May 15, South Korea’s opposition leader derided Japanese leaders’ claims that the water is safe enough to drink: “If it is safe enough to drink, they should use it as drinking water.”

Now, American scientists are raising concerns that marine life and ocean currents could carry harmful radioactive isotopes—also called radionuclides—across the entire Pacific Ocean.

“It’s a trans-boundary and trans-generational event,” says Robert Richmond, director of the Kewalo Marine Laboratory at the University of Hawaii, and a scientific adviser on the discharge plan to the Pacific Islands Forum. “Anything released into the ocean off of Fukushima is not going to stay in one place.”

Richmond cites studies showing that radionuclides and debris released during the initial Fukushima accident were quickly detected nearly 5,500 miles away off the coast of California. Radioactive elements in the planned wastewater discharges may once again spread across the ocean, he says.

The radionuclides could be carried by ocean currents, especially the cross-Pacific Kuroshio current. Marine animals that migrate great distances could spread them too. One 2012 study cites “unequivocal evidence” that Pacific bluefin tuna carrying Fukushima-derived radionuclides reached the San Diego coast within six months of the 2011 accident. No less worrying as carriers, Richmond says, are phytoplankton—free-floating organisms that are the basis of the food chain for all marine life and can capture radionuclides from the Fukushima cooling water. When ingested, those isotopes may “accumulate in a variety of invertebrates, fish, marine mammals, and humans.” In addition, a study earlier this year refers to microplastics—tiny plastic particles that are increasingly widespread in the oceans—as a possible “Trojan horse” of radionuclide transport.

Pacific conveyors

Ocean currents could carry treated radioactive wastewater far from the Fukushima Daiichi nuclear power plant. Scientists in some countries around the Pacific worry about its potential effects on food chains and ecosystems.

That scientists were able to pick up traces of radioactive elements near California after the 2011 accident, Richmond says, “is indicative of what we could expect” over decades of wastewater discharges. He and his fellow scientific advisers to the Pacific Islands Forum recently published an opinion piece saying that not enough is yet known about the wastewater’s potential effects on environmental and human health and calling for Japan to delay the releases.

Richmond and his colleagues are not the only American scientists urgently raising such concerns. This past December, the United States-based National Association of Marine Laboratories—an organization with more than a hundred member labs in the U.S. or U.S. territories—released a statement opposing the wastewater release plan. It cited “a lack of adequate and accurate scientific data supporting Japan’s assertion of safety.” The discharges, the statement said, may threaten the “largest continuous body of water on the planet, containing the greatest biomass of organisms … including 70 percent of the world’s fisheries.”

 

 

 

 

National Geographic-By Lesley M.M. Blume https://www.nationalgeographic.com/premium/article/fukushima-japan-nuclear-wastewater-pacific-ocean