Fukushima radiation
identified off northern California
Satellite measurements of ocean temperature from July 28th to August 4th and the direction of currents help show where radionuclides from Fukushima are transported.
Source: Woods Hole Oceanographic Institution
Low-level radiation from
Japan's Fukushima nuclear accident has been detected in multiple samples of
ocean water off the Pacific Coast of the U.S. and Canada, the Woods Hole
Oceanographic Institution is reporting.
The sample nearest to shore was
taken about 100 miles off the coast of Eureka, in Northern California.
The levels are far below those
that might pose a risk to human health or marine life, said Ken Buesseler, a
WHOI marine chemist who is leading the monitoring effort.
"The levels are only
detectable by sophisticated equipment able to discern minute quantities of
radioactivity," Buesseler said.
And so far, no samples taken from
beaches have tested positive for Fukushima radiation.
Massive amounts of contaminated
water were released from the Fukushima Dai-ichi nuclear power plant following a
March 2011 earthquake and tsunami. Radioactive water has continued to leak and
be released from the complex.
The radioactive plume has traveled
across the Pacific, propelled largely by ocean currents and being
diluted along the way.
No state or federal agency is
testing Pacific waters for radiation from the crippled plant, so earlier this
year Buesseler launched a crowd-funded, citizen-science effort to collect surf
samples to be tested at his lab in Massachusetts.
Buesseler is looking for
cesium-134, the so-called "fingerprint" of Fukushima. Cesium-134 does
not occur naturally in the environment and has a short two-year half-life, so
any in the Pacific today had to come from Fukushima.
He's also looking for
higher-than-background levels of cesium-137, another Fukushima isotope that
already is present in the world's oceans from nuclear testing in the 1950s and
1960s.
Processing has been completed
on about 50 of the surf samples, taken from the Bering Strait to San Diego.
None have been positive for Fukushima radiation.
But this summer Buesseler
partnered with a group of volunteers on the research vessel 'Point Sur' to take
a series of about 50 samples offshore, from Dutch Harbor, Alaska to Eureka.
So far, about 20 of those
samples have been analyzed, and 10 have been positive for cesium-134, the
Fukushima fingerprint. All were relatively close to the surface.
The amount of cesium-134 in
each sample was less than 2 becquerels per cubic meter (Bq/m3). That's about
1,000 times lower than the acceptable limit in drinking water set by the U.S.
Environmental Protection Agency.
"I don't want to be
dismissive of concerns," Buesseler said. "But there's a big
difference between ten million becquerels – and it was that high off Japan in
2011 – and a few of these becquerels like we're seeing off Eureka."
"It's not zero," he
said. "But it's not some large, dangerous amount of cesium that might
reach our shorelines."
It's hard to predict when the
Fukushima isotopes will reach beaches, Buesseler said.
"The models predict cesium
levels to increase over the next two to three years, but do a poor job
describing how much more dilution will take place and where those waters will
reach the shoreline first," he said.
Buesseler is presenting his
findings Thursday at the Society of Environmental Toxicology and Chemistry's
annual meeting in Vancouver, BC.
tloew@statesmanjournal.com, (503)
399-6779 or follow at Twitter.com/SJWatchdog
Ask the scientist
Woods Hole Oceanographic
Institution marine chemist Ken Buesseler will respond to questions from the
public on the "Ask Me Anything"
forum on Reddit at 10 a.m. today.
Learn more about the project
at http://www.ourradioactiveocean.org/
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