Nuclear experts from the International Atomic Energy Agency (IAEA) are expected to formally endorse Japan’s controversial plan to release radioactive wastewater from the Fukushima Daiichi nuclear power plant into the Pacific Ocean this week, but is it the right thing to do?
In 2011, Japan was hit by a severe earthquake and tsunami that caused three reactors to melt down at Fukushima. The contaminated water, which currently sits in about 1,000 giant tanks at the site, was used to keep Fukushima’s reactors and debris cool after the disaster.
Japan wants to gradually release 1.3 million cubic meters of this water into the sea over the next three to four decades, so that it can continue with the decommissioning of the Fukushima site.
The water has already been treated to remove 62 radioactive contaminants, but it remains contaminated with tritium, a radioactive isotope of hydrogen. Because tritium is bound to the water molecule itself, it’s hard to remove, he says. Ian Farnan at Cambridge University. It is not really possible to separate [tritium from water],” he says.
Tritium, which has a radioactive half-life of just over 12 years, emits low-energy beta particles and does little damage to cells, Farnan says. Because of its bond with water, it will pass through most marine organisms harmlessly, he says. Many nuclear plants around the world already discharge tritium into the ocean.
Japan says it must start dump the water early because the tanks will reach capacity in 2024. He insists the wastewater will be diluted to ensure tritium levels never exceed World Health Organization guidelines.
But Porcelain, South Korea and Pacific island nations have expressed doubts about Japan’s discharge plan, amid fears that the sewage discharge could contaminate the marine food chain. In January, Henry Puna of the Pacific Islands Forum He said he has “serious concerns” about the proposed ocean release..
A 2021 study suggested that if the contaminated wastewater were released gradually, peaks in tritium concentrations would be confined to the east coast of Japan and would represent only a small fraction of the background concentration of tritium already present in the ocean.
Awadhesh Jha at the University of Plymouth, UK, warns that more research is needed to investigate the risks posed by tritium to the marine food chain. Jha’s lab experiments suggest that tritium can accumulate in the tissues of shellfish such as mussels and oysters. but little is known about the impact of exposure in the real world. “It takes an international [research] effort,” he says.
Meanwhile, Tokyo Electric Power Company, the company that runs the site, has admitted that the water in the tanks will need additional “secondary” treatment to filter out the most dangerous isotopes, such as ruthenium-106, cobalt-60 and strontium-90, to meet regulatory standards. But traces of these harmful isotopes will remain, experts warn, and their the impact on marine life is unknown.
But ultimately, Jha says, Japanese authorities have no choice but to dump the contaminated water into the ocean, particularly given the earthquake risk of storing it on land. “They have no other options,” he says.