On April 11, 2021, a journalist at state-controlled broadcaster China Global Television Network (CGTN), Shen Shiwei, claimed in a tweet that Japan’s plan to release wastewater from the wrecked Fukushima nuclear reactors would pollute half of the Pacific ocean within 57 days.
The post contained a simulation video from the German Institute Helmholtz Centre for Ocean Research Kiel (GEOMAR), which supposedly shows how the contaminated nuclear wastewater will spread. Chinese ambassador to the Association of Southeast Asian Nations (ASEAN), Deng Xijun, repeated the claim in his tweet on the following day.
The video clip included in the two tweets has been viewed over 400,000 times and each post has been retweeted more than 700 times.
A similar video and claim were also posted on Douyin by Chinanews.com, saying the model stimulation from GEOMAR is terrifying. The Douyin video got more than 3,000 shares and 377,000 likes.
The clip has also been manipulated. It is cropped to make the covered area in the ocean appear bigger than in the original video, presumably to match the claim.
In fact, the 2012 original simulation showed the findings of a study titled “Model simulations on the long-term dispersal of Cs-137 released into the Pacific Ocean off Fukushima,” authored by Erik Behrens, Franziska U Schwarzkopf, Joke F Lübbecke, and Claus W Böning at GEOMAR.
It demonstrates a projected spread of radioactive cesium-137 in the aftermath of the 2011 Tohoku earthquake and the subsequent nuclear crisis at Fukushima.
In the original video, the 57th day looks like the screen capture below.
Annie Lab measured the color-coded area by overlaying it on a map through an online tool called Georeferencer.
Our estimation indicates the area reached by the tracer cloud covered approximately 2,235,115.25 square kilometers, which is less than two percent of the Pacific Ocean’s total area of 155 million square kilometers.
Annie Lab also plotted the colored area on the Pacific Ocean on Google Earth to visualize its comparative size (as seen below).
The tracer does not cover half of the Pacific Ocean. It occupies less than two percent of the entire ocean.
The manipulated video in the tweets in question cropped the original clip to remove the frame of reference on the map, the scale for radiation isotope concentration and the timescale of isotope dispersion.
It also omitted the slower movement at the end of the original and accelerated the speed of the tracer, which made it appear to spread faster.
Some dramatic background music was also added to replace the voice-over in the original video that described the rate of the spread of cesium.
Japan’s announcement of the plan to release the treated radioactive water from the ruined Fukushima nuclear power plant was immediately denounced by neighboring countries such as South Korea and China.
Annie Lab can only confirm that the video used in the tweets in question has been manipulated. It does not show what they claim. We cannot determine the impact of the planned operation on the environment.