For the first time, seaborne radiation from Japan’s Fukushima nuclear disaster has been detected on the West Coast of the United States.
Cesium-134, the so-called fingerprint of Fukushima, was measured in seawater samples taken from Tillamook Bay and Gold Beach in Oregon, researchers from the Woods Hole Oceanographic Institution are reporting.
Because of its short half-life, cesium-134 can only have come from Fukushima.
Also for the first time, cesium-134 has been detected in a Canadian salmon, the Fukushima InFORM project, led by University of Victoria chemical oceanographer Jay Cullen, is reporting.
In both cases, levels are extremely low, the researchers said, and don’t pose a danger to humans or the environment.
Massive amounts of contaminated water were released from the crippled nuclear plant following a 9.0 magnitude earthquake and tsunami in March 2011. More radiation was released to the air, then fell to the sea.
Woods Hole chemical oceanographer Ken Buesseler runs a crowd-funded, citizen science seawater sampling project that has tracked the radiation plume as it slowly makes its way across the Pacific Ocean.
The Oregon samples, marking the first time cesium-134 has been detected on U.S. shores, were taken in January and February of 2016 and later analyzed. They each measured 0.3 becquerels per cubic meter of cesium-134.
Buesseler’s team previously had found the isotope in a sample of seawater taken from a dock on Vancouver Island, B.C., marking its landfall in North America.
Meanwhile, in Canada, Cullen leads the InFORM project to assess radiological risks to that country’s oceans following the nuclear disaster. It is a partnership of a dozen academic, government and non-profit organizations, including Woods Hole.
Last month, the group reported that a single sockeye salmon, sampled from Okanagan Lake in the summer of 2015, had tested positive for cesium-134.
The level was more than 1,000 times lower than the action level set by Health Canada, and is no significant risk to consumers, Cullen said.
Buesseler’s most recent samples off the West Coast also are showing higher-than background levels of cesium-137, another Fukushima isotope that already is present in the world’s oceans because of nuclear testing in the 1950s and 1960s.
Those results will become more important in tracking the radiation plume, Buesseler said, because the short half-life of cesium-134 makes it harder to detect as time goes on.
Cesium-134 has a half-life of two years, meaning it’s down to a fraction of what it was five years ago, he said. Cesium-137 has a 30-year half-life.
A recent InFORM analysis of Buesseler’s data concluded that concentrations of cesium-137 have increased considerably in the central northeast Pacific, although they still are at levels that pose no concern.
“It appears that the plume has spread throughout this vast area from Alaska to California,” the scientists wrote.
They estimated that the plume is moving toward the coast at roughly twice the speed of a garden snail. Radiation levels have not yet peaked.
“As the contamination plume progresses towards our coast we expect levels closer to shore to increase over the coming year,” Cullen said.
Even that peak won’t be a health concern, Buesseler said. But the models will help scientists model ocean currents in the future.
That could prove important if there is another disaster or accident at the Fukushima plant, which houses more than a thousand huge steel tanks of contaminated water and where hundreds of tons of molten fuel remain inside the reactors.
In a worst-case scenario, the fuel would melt through steel-reinforced concrete containment vessels into the ground, uncontrollably spreading radiation into the surrounding soil and groundwater and eventually into the sea.
“That’s the type of thing where people are still concerned, as am I, about what could happen,” Buesseler said.
Scientists now know it would take four to five years for any further contamination from the plant to reach the West Coast.
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Tracking the plume
Scientists are beginning to use an increase in cesium-137 instead of the presence of cesium-134 to track the plume of radioactive contamination from Japan’s Fukushima nuclear disaster. These figures show the increase in cesium-137 near the West Coast between 2014 and 2015.
Graphic courtesy Dr. Jonathan Kellogg of InFORM, with data from Dr. John Smith, Department of Fisheries and Oceans Canada, and Dr. Ken Buesseler, Woods Hole Oceanographic Institute.
Our Radioactive Ocean
Learn more about Ken Beusseler’s crowd-funded, citizen-science seawater sampling project at http://www.ourradioactiveocean.org/.
See test results at http://www.ourradioactiveocean.org/results.html.
Fukushima Radiation Hits U.S. West Coast: Should Americans Be Concerned?
With news of a Fukushima radiation leak reaching America’s West Coast having emerged earlier this week, many have expressed concern that the seaborne leak of cesium-134 may make it dangerous for people to eat seafood caught from, or swim in those areas. But a new report has sought to reassure West Coast residents that the radiation from the Fukushima nuclear disaster may not be that harmful after all.
The Fukushima nuclear disaster took place in the aftermath of the Tohoku earthquake, a magnitude 9.0 tremor that shook Japan on March 11, 2011, and triggered massive tsunami waves in its wake. Due to the strength of the quake and the ensuing tsunami, the Fukushima Daiichi nuclear plant’s cooling systems were destroyed, leading to three nuclear meltdowns and constant radiation emissions since the day after the quake. Some researchers had posited that the Fukushima disaster was worse than 1986’s Chernobyl meltdown, though other sources, such as The Conversation, wrote that Chernobyl still emitted far more radiation and created greater cancer risks for workers on site.
The Inquisitr reported earlier this week on the discovery of Fukushima radiationfrom Tillamook Bay and Gold Beach in Oregon. Researchers from the Woods Hole Oceanographic Institution were quoted as saying that they had found cesium-134, the key elemental ingredient in the Fukushima nuclear disaster, in the two Oregon beaches. This was the first time the isotope had been found on U.S. shores and came after it was found from a Vancouver Island seawater sample.
— Gunel_Beva (@CurrentNews_EN) December 11, 2016
Although it is a bit worrisome that Fukushima radiation has hit America, experts believe that the levels are so low that people living on the West Coast can still eat fish as usual, or take a swim in the ocean. Woods Hole Oceanographic Institution senior scientist Ken Buesseler told USA TODAY just how insignificant the amounts of cesium-134 are at this point.
“To put it in context, if you were to swim every day for six hours a day in those waters for a year, that additional radiation from the addressed cesium from Japan… is 1000 times smaller than one dental x-ray.”
Buesseler added that the seawater samples, which were taken in Oregon in January and February 2016, only measured 0.3 becquerels per cubic meter of cesium-134. He also stressed that the levels of the radioactive material were much greater in Japan in the immediate aftermath of the Fukushima nuclear disaster.
“In Japan, at its peak, it was 10 million times higher than what we are seeing today on the West Coast.”
Another reason why people shouldn’t be too worried about the radiation is the fact that cesium-134 has a half-life of just about two years. According to the New York Post, that means radiation levels are sliced in half every two years. In contrast, the isotope cesium-137, which was a key feature in the Chernobyl disaster, has a half-life of 30 years. Dr. Kathryn Higley, head of Oregon State University’s School of Nuclear Science and Engineering, said that cesium-134 levels in Japan have also gone down significantly enough that some Japanese fisheries are considering reopening, a good five years after the Fukushima nuclear disaster.
— Kate Llewellin Ⓥ (@DolphinSeeker30) December 11, 2016
While the Fukushima radiation might not pose a threat at the moment to West Coast residents, Buesseler lamented the lack of government funding for radioactive studies that would allow researchers to better track and measure radiation levels. As such, Buesseler said, scientists have relied heavily on crowdfunding initiatives, such as his own project Our Radioactive Ocean. USA TODAY describes the project as a “crowdfunded, citizen science seawater sampling” initiative.
Meanwhile, Buesseler does not foresee any health issues occurring among people who swim in, or eat fish caught from affected waters, but said that Woods Hole would continue monitoring levels until the Fukushima-based radiation levels go down.