On March 11, 2011, Japan experienced a trio of disasters. A 9.0 magnitude earthquake struck 80 miles off the coast, triggering a series of tsunamis that hit the island nation within minutes. In turn, these massive waves struck the Fukushima Dai-ichi nuclear power plant, causing a loss of power, overheating, and resulting explosions that released radioactivity into the ocean and on land. Nearly seven years later, scientists say this flow of radioactive water is still seeping into the sea.
On Wednesday at the 2018 annual meeting of the Atomic Energy Society of Japan, Michio Aoyama, Ph.D., announced that radioactive water surrounding the plant’s damaged Unit 1 is flowing into the Pacific Ocean at a rate of approximately 2 billion becquerels a day. Aoyama, who is a professor at the Institute of Environmental Radioactivity at Fukushima University, had previously said the flow was a rate of 30 billion becquerels in 2013. This current concentration of radiation, in the scheme of things, is an improvement, and a level that Aoyama says shouldn’t affect the local fishing industry.
Much of this radioactive water was created when water was doused on the melted nuclear fuel contained at the plant’s three damaged reactors. After being used to cool the fuel, the water accumulated in the building’s basements and today, Ayoama told Japan Times “it can be assumed that there is a path from the complex to the ocean.” Radioactive water also entered the ocean after the initial 2011 accident: The nuclear power plant meltdown caused the largest single release of human-made radioactive discharge in history, with 80 percent of the fallout happening in the Pacific Ocean.
The environmental cost of this is still being studied by scientists. Researchers have determined the surrounding waters have elevated levels of the nuclear by-product cesium but state they are “below the threshold of concern” for human exposure. While many fisheries off the coast of Fukushima are still closed because the levels of cesium are above the legal limit for seafood, a 2016 study published in Integrated Environmental Assessment and Management found “radioactivity levels in the marine biota near Fukushima were lower than predicted” and “exposures were too low for acute effects at the population level to be observed in marine organisms.”
In an effort to curb this flow, the central government spent $320 million in 2016 to build an underground “ice wall,” a mile long wall of frozen dirt designed to seal the ocean from radioactive groundwater. However, the seepage of toxic water has continued.
This new study is another indication of this continued flow of radioactive water. Of a major concern to scientists is what the longterm effects of this contamination will be, and how far the flow will spread. In 2015, radioactive contamination that began in Fukushima was found on the coasts of British Columbia and California.