As Japan Moves to Release Fukushima Wastewater into the Ocean, Questions Persist

In 2021, Japan announced that it will release treated radioactive wastewater from the disabled Fukushima nuclear plant into the sea as part of its plan to decommission the power station when its storage capacity reaches its limit this year. Releasing 1.4 million tons of the contaminated water into the Pacific Ocean might sound like a terrible idea. But scientific data and the world’s premier nuclear agency say that doing so will not hurt people, marine life or the environment.

Most of the radioactivity in the water is from tritium, a type of hydrogen found in far higher quantities in the ocean. The rest of the radioactivity is so tiny that, even in the most extreme scenario, the radiation from eating fish amounts to that of a dental x-ray.

The liquid waste at Fukushima would fill 500 Olympic swimming pools and is mostly regular water. A process called ALPS, or Advanced Liquid Processing System, removes problematic isotopes such as cesium-137, strontium-90 and iodine-129. Repeating the treatment cycle makes the radioactivity as small as needed.

For technical reasons, ALPS cannot remove tritium or carbon-14. Both isotopes occur naturally, and so the question of safety boils down to how the Fukushima radioactivity compares to everyday life. Carbon-14 is found in all living things and is used in radiocarbon dating, but tritium is less familiar and has raised the greatest concern.

Tritium by the numbers

Around 140g to 200g of tritium is produced in the upper atmosphere every year. The Pacific Ocean contains around 8400g of tritium, while the total amount of tritium at Fukushima is less than 3g.

Japanese authorities plan to release the water gradually over a period of around 40 years. Each year, around 0.06g of tritium will be added to the ocean which will change tritium levels in the Pacific by less than 0.001 percent annually. 

A recent study by two government institutes in South Korea used computer models to predict how Fukushima tritium moves with ocean currents. They found tritium levels in Korean waters would rise by less than six parts per million, a change too small to detect.

Marine impact

A 2021 study shows that eating a lifetime’s worth of Fukushima fish caught entirely within a few kilometers of the wastewater outlet amounts to 0.02 micro-sieverts of tritium radiation. This is less than a banana, which contains the equivalent of 0.1 micro-sieverts.

The same study shows the lifetime effect of all other isotopes is 5 micro-sieverts, the same as a dental x-ray. In reality, fish will swim all over the place but it is comforting to know that, even in the most extreme case, the amount of radiation over 50 years equals one dental check-up.

For fish 20km from the outlet, the lifetime dose falls by a factor of 100. This is effectively zero compared to natural background radiation, where typical exposure is between 1500 and 3500 micro-sieverts per year.

The study also considers marine life, looking at fish species, sedimentation, biological concentration and organic tritium. The story is the same as for people, with no impact. The maximum marine dose near the outlet is 7 micro-grays per year, more than 10,000 times smaller than the zero-effect benchmark of around 90,000 micro-grays per year.

The big picture

Despite the attention, tritium makes a small contribution to radioactivity in the ocean. Most ocean radioactivity is from other sources: 91 percent from potassium-40, 8.6 percent from rubidium-40, 0.3 percent from uranium. These naturally occurring elements have always been in the ocean and are older than Earth itself.

Together, tritium and carbon-14 contribute just 0.08 percent of ocean radioactivity. For carbon-14, this amounts to 18 million grams already in the Pacific Ocean. The Fukushima water contains just one extra gram of carbon-14. This miniscule addition puts to rest the suggestion by Greenpeace that carbon-14 is a dangerous aspect of the Fukushima water.

The International Atomic Energy Agency (IAEA) has examined the Fukushima wastewater plans and supports ocean release. The IAEA will perform its own measurements to ensure the water is safe. Additional cross-checking comes from the Japanese Nuclear Regulation Authority, which is independent of local authorities at Fukushima.

It is understandable that some are concerned and seek reassurance. But the scientific case is strong when the full story is told. And once the water is released, much-needed space at the site will be freed up, allowing engineers to get on with vital remedial works.

How Fukushima wastewater will disrupt seafood trade

Computer modeling predicts that the global seafood market could turmoil with the release of the Fukushima nuclear wastewater. Seafood is one of the most important food commodities in international trade, far exceeding meat and milk products. According to the United Nations Comtrade database, global seafood trade has grown from USD$7.57 billion in 2009 to USD$12.36 billion in 2019, an increase of 63.2 percent.

The Japanese nuclear wastewater discharge raises global worries about the safety of Japanese seafood as public opinion influences consumers’ preference for seafood. In an empirical study involving American consumers published in 2013, 30 percent of respondents said they reduced their seafood consumption following the Fukushima nuclear plant accident and more than half believe Asian seafood poses a risk to consumer health due to the disaster. Most of Japan’s seafood trading partners, such as China, Russia, India and South Korea, imposed temporary bans on food from several districts around Fukushima in wake of the accident in 2011.

A paper published in Ocean & Coastal Management in November 2022 models the potential impact of the Fukushima nuclear wastewater disposal on the global seafood trade using the import and export data for 26 countries which make up more than 92 percent of the world’s trade in marine products.

A community classification theory of complex networks was used to classify seafood trading countries into three communities. Seafood trade is frequent among countries within each individual community and less between the communities. The first community contains Ecuador, Italy, Morocco, Portugal and Spain. The second contains Denmark, France, Germany, Iceland, New Zealand, Nigeria, Norway, Poland, Sweden, and the United Kingdom. The third community contains China, India, Indonesia, Japan, South Korea, Malaysia, Taiwan of China, Russia, Thailand, the United States and Vietnam. 

Modelling shows China, South Korea, and the US maintain a steady trade of seafood imports and exports between them. Data used for the modelling shows that the rate of change in trade between China and Korea, China and the US and between Korea and the US is very close to zero. China, South Korea and the US, however, are expected to increase their seafood imports from Denmark, France, Norway and other community group two countries while reducing seafood exports to them. This is because these three countries have already reduced their seafood trade with Japan.

The increase in exports from community group three to community group two nations leads to a decrease in imports and exports between countries within community group two. For example, the study notes that Denmark, Norway and France are all experiencing a decrease in seafood exports and imports between each other. While the rates of change in trade between countries look very close, the size of each country’s import and export market is different, so the actual trade volume can vary greatly. The model also divided the global seafood market into two segments – the first being the Japanese market and the second comprising 25 other countries. It calculated that Japan's seafood exports fell by 19 percent in 2021, or USD$259 million.

The Japanese government has announced it will spend USD$260 million to buy local seafood products if domestic sales are affected by the release of Fukushima wastewater. If the Japanese public is more accepting of seafood caught in waters around the discharge area, seafood imports from other countries to Japan will likely fall. However, if public opinion does not go this way, Japan will have to import more seafood to meet local demand. If 40 percent of the reduction in Japanese seafood exports is absorbed by its own market, the modelling shows this would result in a USD$272 million reduction in Japanese seafood imports from other countries.

Countries in the same community as Japan show a more significant reduction in their seafood exports to Japan while countries not in the same community have less impact. The planned Fukushima nuclear wastewater disposal will mainly affect countries in the same seafood trading community as Japan. These countries will see more significant reductions in their imports of Japanese seafood and in the exports of their seafood to Japan compared to countries in other communities. 

Alternatives to dumping Fukushima wastewater into the Pacific

Some experts argue that there are compelling data-backed reasons to examine alternative approaches to the wastewater dumping. The apparent rush to treat, dilute and dump should be postponed until further due diligence can be performed. 

During a visit to the Fukushima site in February 2023, it was apparent that large amounts of concrete will need to be used to expand the seawall, stabilize large amounts of contaminated soil and fortify the ice barrier presently in place to reduce groundwater flow into the damaged reactors. Using the treated cooling water onsite to mix concrete that can be used to expand the seawall should be given more consideration if the water is truly safe, as it removes the issue of ocean release and would substantially reduce the volume of stored cooling water.

The present situation arose from a classic type II statistical error: accepting a false hypothesis (of safety of the nuclear power plant siting, with inadequate safety measures). A more detailed set of analyses that includes problematic scenarios can help prevent another calamity. 

Claims of total safety are not supported by the available information. The world’s oceans are shared among all, providing over 50 percent of the oxygen we breathe, and a diversity of resources of economic, ecological and cultural value for present and future generations. Within the Pacific Islands in particular, the ocean is viewed as connecting, rather than separating, widely distributed populations.

The risks of wastewater

Releasing radioactive contaminated water into the Pacific is an irreversible action with transboundary and transgenerational implications. As such, it should not be unilaterally undertaken by any country. The Pacific Islands Forum has had the foresight to ask the relevant questions on how this activity could affect the lives and livelihoods of their peoples now and into the future. It has drawn on a panel of five independent experts to provide it with the critical information it needs to perform its due diligence. 

No one is questioning the integrity of Japanese or International Atomic Energy Agency scientists, but the belief that our oceans’ capacity to receive limitless quantities of pollutants without detrimental effects is demonstrably false. For example, tuna and other large ocean fish contain enough mercury from land-based sources to require people, especially pregnant women and young children, to limit their consumption. Tuna have also been found to transport radionuclides from Fukushima across the Pacific to California.

Phytoplankton, microscopic organisms that float free in the ocean, can capture and accumulate a variety of radioactive elements found in the Fukushima cooling water, including tritium and carbon-14. Phytoplankton is the base for all marine food webs. When they are eaten, the contaminants would not be broken down, but stay in the cells of organisms, accumulating in a variety of invertebrates, fish, marine mammals and humans. Marine sediments can also be a repository for radionuclides, and provide a means of transfer to bottom-feeding organisms.

The justification for dumping is primarily based on the chemistry of radionuclides and the modelling of concentrations and ocean circulation. But the assumptions that underpin this modelling may not be correct. It also largely ignores the biological uptake and accumulation in marine organisms and the associated concern of transfer to people eating affected seafood. Many of the 62-plus radionuclides present in the Fukushima water have long periods over which they can cause harmful effects, called half-lives, of decades to millennia. 

For example, cesium-137 has a half-life of 30 years, and carbon-14, more than 5,700 years. Issues like this really do matter, as once radioactive materials enter the human body, including those that release relatively low-energy radiation (beta particles), they can cause damage and increase the risk of cancers, damage to cells, to the central nervous system and other health problems.

The Fukushima nuclear disaster is not the first such event, and undoubtedly will not be the last. The challenge of cleaning-up, treating and containing contaminated cooling water is also an opportunity to find and implement safer and more sensible options and setting a better precedent to deal with future catastrophes. 

Wastewater worries: A Chinese government spokesman caused a stir when he tweeted this illustration – a twist on the Hokusai print – after Japan announced its plans to release the Fukushima wastewater into the ocean (Credit: Twitter)

The Pacific region and its people have already suffered from the devastation caused by United States, British and French nuclear testing programs. Documented problems have led to international agreements to curtail such testing. In this case, the members of the Pacific Islands Forum are key stakeholders that are finding a unified voice against the planned dumping of radionuclides and other pollutants into the ocean that surrounds their homes and holds their children’s futures.

The world’s oceans are in trouble and experiencing mounting stress from human-induced impacts tied to global climate change, overfishing and pollution, with consequential cumulative effects on living resources and the people who depend on them. Pollution, particularly from land-based sources, is one of the greatest threats to ocean resource sustainability and associated elements of human health. 

Instead of dumping this water now, a more deliberative and prudent approach would adhere to the precautionary principle – that if we are not sure no harm will be caused, then we should not proceed.

Respect for the health of our shared ocean and the well-being of the people of Japan and the Pacific region requires sound scientific practices, a more careful consideration of the alternative more data, deliberation, and a more comprehensive Radiological Environmental Impact Assessment.

It is hoped the commitment made during the recent meetings in Japan to pursue further open discussions and information exchanges among the Pacific Island Forum expert panel and Japanese and IAEA scientists will result in a consensus on the best way forward, and provide the best available science to guide decision makers in their critical deliberations.