Trace amounts of radiation from the ruined Fukushima nuclear power plant in Japan were found in water samples collected in the Pacific Ocean 100 miles due west of Eureka, a Massachusetts-based researcher reported.
The concentration of cesium-134, a radioactive isotope known to come from the earthquake-and-tsunami ravaged Fukushima plant, was just barely detectable by his equipment and far below a level that would pose a risk to human health or marine life, said Ken Buesseler, a Woods Hole Oceanographic Institute marine chemist who has been monitoring North American coastal waters since January.
“We knew it was out there,” Buesseler said in a telephone interview Tuesday. “It’s good to be getting some numbers.”
Cesium in the sample collected in August offshore from Eureka was less than 2 becquerels per cubic meter, he said. The acceptable U.S. limit for cesium in drinking water is 7,400 becquerels.
“It wouldn’t stop me from swimming in it or from eating any local seafood,” Buesseler said.
Still, it is the first positive test for Fukushima radiation in water off the West Coast of the United States obtained by Buesseler’s crowd-funded, citizen-science program to collect and test water samples for cesium-134, the telltale marker for radiation from the Japanese power plant meltdown that followed the March 2011 earthquake and tsunami.
None of the more than 50 coastal seawater samples collected from Alaska to San Diego and on the north shore of Hawaii has shown any detectable amount of cesium-134, Buesseler said. But John Smith, a Canadian scientist, found levels of cesium similar to Buesseler’s sample on research cruises offshore from Canada earlier this year, according to a news release from the Woods Hole institution.
Scientific models have indicated a radioactive plume stretching 5,000 miles across the Pacific Ocean and expected to appear offshore of Alaska and the coast of Canada, move south along the coast of North America and eventually back toward Hawaii, the release said.
But the models “differ greatly on when and how much would be found,” it said.
The radioactive sample was collected in August by volunteers on the research vessel Point Sur sailing between Dutch Harbor, Alaska, and Eureka. Eureka is about 240 miles north of Bodega Bay.
Results of all samples taken and tested by Buesseler’s program are posted online at www.OurRadioactiveOcean.org.
The list includes a sample collected at Bodega Head on June 1 and three samples collected at Point Reyes in January, April and June. All four samples indicated a cesium-134 level “below detection,” or less than 0.2 becquerels per cubic meter.
A sample collected at the Farallon Islands in April had the same finding.
Dan Sythe, CEO of International Medcom, a Sebastopol company that makes radiation detection equipment, said he and Buesseler collected the seawater sample at Bodega Head.
Sythe, who plans to collect another sample on Nov. 22, said he’s been concerned since the Fukushima meltdown that radiation would reach the California coast. His company has conducted a small sampling program of seaweed and fish from Bodega Bay and tested it for radiation.
No radiation has been found here since the spring of 2011, Sythe said, but he shares Buesseler’s concern that the federal government is not monitoring West Coast waters. Some people are “on edge” about the prospect of Fukushima radiation reaching them, he said.
The radiation now reaching California is at the front edge of the plume, and Buesseler said the concentration is expected to increase, possibly to 10 becquerels, still a low level, over the next two to three years. But it’s worrisome, he said, that what’s happening now in Japan will reach North America in about three years.
News reports said that cesium contamination reached record levels — three times higher than previously recorded levels — after a typhoon swept through Japan last month. Buesseler said the ocean waters off Japan now contain equal concentrations of cesium and strontium-90, a dangerous isotope that lodges in bones and can cause cancer when ingested.
On shore at Fukushima, more than 1,000 storage tanks are holding water that was pumped out of the damaged reactor buildings with strontium-90 levels more than a hundred times greater than releases in 2011, Buesseler said.
“The red flag is we don’t know enough to predict this very well,” he said, referring to radiation’s slow movement across the Pacific Ocean.
You can reach Guy Kovner at 521-5457 or guy.kovner@ pressdemocrat.com. On Twitter @guykovner.