Radiation in the Pacific Ocean near Japan’s Fukushima nuclear plant is at levels as high, or higher, than has been measured in the past three years, as the crippled plant continues to bleed contamination into the sea, new results from a Woods Hole Oceanographic Institution research cruise show.
“We think it’s related to the ongoing leaks,” said Ken Buesseler, a Woods Hole chemical oceanographer who is among a handful of scientists studying the contamination and its path across the ocean to North America. “It’s a little surprising and contrary to claims they’ve stopped all flow. So we’re not out of the woods yet.”
Friday will mark five years since a 9.0 magnitude undersea earthquake shook the Tohoku area, 170 miles north of Tokyo. Fifty minutes after the shaking stopped, a wall of water arrived, reaching heights of 130 feet and moving inland as much as six miles in some places. About 20,000 people died, mostly from drowning.
The tsunami swamped Fukushima Daiichi’s seawall, knocking out power to four of its six nuclear reactors. Without power to pump cooling water, three of those reactors melted down, spewing radiation into the air and sea. It was the worst nuclear disaster since Chernobyl, in 1986.
Unlike Chernobyl, however, this crisis played out slowly, and continues today, on both sides of the Pacific.
At the plant, hundreds of tons of molten fuel remain inside the reactors.
TEPCO, the Japanese utility that operates the plant, hopes someday to remove the fuel, but the technology to do so does not exist today. Experts aren’t even sure where it is – two attempts last year to send in robot cameras failed.
In a worst-case scenario, the fuel would melt through the steel-reinforced concrete containment vessels into the ground, uncontrollably spreading radiation into the surrounding soil and groundwater and eventually into the sea.
For now, pumps pour a constant stream of water into the vessels and TEPCO collects the water that leaks out, as well as groundwater that continues to filter through the plant.
All that contaminated water is filtered to remove some – but not all – of the dangerous radionuclides. It’s stored onsite in huge steel tanks which now number more than 1,100.
Another earthquake or tsunami could wash that contaminated water back into the sea.
“There is a lot more strontium on the site in the tanks than was ever released in 2011,” Buesseler said. “A catastrophe today could change things completely in three to five years on the West Coast.”
In October 2015, Buesseler’s team took new samples from as close as a half-mile away from the nuclear power plant.
Levels there remain elevated, he said, confirming continued releases from the plant.
The levels are thousands of times lower than during the peak in 2011, Buesseler said, and most fish near the plant now are below regulatory limits for radiation.
Still, he said, “The fact that it’s still leaking is always of concern. We don’t want additional radioactivity in the ocean.”
Five thousand miles across the Pacific, on the West Coast of North America, the disaster continues to play out as well.
Shortly after the earthquake, a tsunami warning was issued for most of the West Coast and all of Oregon. Tsunami surges of as much as 8 feet hit some areas, causing major damage at ports in Brookings and in Crescent City, Calif.
Brookings has received about $7 million in state and federal funding to rebuild.
In late March 2011, radiation showed up in rainwater and milk samples along the West Coast, although at levels officials said were too low to be of health concern.
That was followed, beginning about a year later, by a wave of tsunami debris, including a 188-ton, 66-foot-long dock that arrived on Agate Beach on June 4, 2012.
As it dealt with its own cleanup and recovery, Japan made a gift of $5 million to the United States to help clean up tsunami debris.
Of that, Oregon received $250,000, and just finished spending it all in January 2016.
Now, the state will take the focus off of tsunami debris, but continue its push to prevent and clean up all marine debris, said Chris Havel, spokesman for the Oregon Parks and Recreation Department, which has jurisdiction over the state’s beaches.
“Some of the debris that’s washing ashore is almost certainly from the tsunami, but a lot of it is not,” Havel said. “We’re seeing a lot of stuff that’s just falling off ships from our own community.”
The state still will fund its 211 phone system to take calls about debris. And it still will provide garbage bags and pick them up for disposal. But it’s currently changing its beach signs to read “marine debris watch” rather than “tsunami debris watch,” Havel said.
Initial concerns that the debris might be radioactive were soon put to rest, but the real threat of invasive species remains, said Caren Braby, marine resources program manager for the Oregon Department of Fish and Wildlife.
The dock, for example, harbored 118 species of foreign marine life.
“It essentially was like a spaceship going out and finding a new planet,” Braby said. “We had built them this transport mechanism to get from there to here.”
None of the species has yet taken a foothold, as far as scientists can tell. And the risk decreases over time, Braby said. But, she said, “Ten, 20, 30 years from now, we might discover one of these species has been able to establish a reproductive population.”
Meanwhile, in the absence of any government testing, Woods Hole’s Buesseler launched a crowd-funded, citizen-science project to track the radiation plume across the Pacific.
Volunteers collect seawater samples from sites all along the West Coast, then send them to Buesseler’s lab in Massachusetts to be tested.
Buesseler also partnered with other organizations to collect samples at sea and along the coast of Japan.
In October 2014, Buesseler reported that a sample taken about 745 miles west of Vancouver, British Columbia, tested positive for cesium-134, the so-called fingerprint of Fukushima because it can only have come from the plant.
The sample also showed 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.
In November 2014, Buesseler reported that Fukushima radiation had been identified in 10 offshore samples, including one 100 miles off the coast of Eureka, California.
In April 2015, Buesseler's team announced it had found Fukushima radiation in a sample of seawater taken from a dock on Vancouver Island, B.C., marking the first time it was recorded on West Coast shores.
And in December 2015, Buesseler reported the highest detected level to date, of 11 becquerels per cubic meter of seawater (about 264 gallons) in a sample collected about 1,600 miles west of San Francisco.
Still, he emphasizes, that’s 500 times lower than U.S. government safety limits for drinking water.
Now, Buesseler is testing a handful of the samples with the highest cesium readings for strontium-90, considered the most dangerous component of radioactive fallout because it accumulates in bones and can cause cancer.
It has not been detected above background levels in any samples taken from West Coast shores, Buesseler said.
“What we’ve confirmed is there’s no detectable increase in strontium-90 in our side of the Pacific,” he said.
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