When friends and family started asking Steven Manley, a marine biologist and professor at California State University, Long Beach (CSULB), if their local coastlines were safe from Fukushima radiation, he decided to find out.
In 2011, the 9.0 earthquake that struck off the coast of Japan triggered a tsunami that caused three meltdowns at Fukushima I nuclear plant. Radioactive material spilled into the ocean, and many feared the worst.
Manley and Kai Vetter, Berkeley Lab’s head of Applied Nuclear Physics, have undertaken “Kelp Watch 2014,” a yearlong research effort to measure Fukushima-related contamination. The researchers will continue to analyze kelp samples shipped in from all along the coast– from Baja, California to Kodiak Island, Alaska.
Manley said there was very little radiation in the sea water from the first collection.
“In fact, the results can only be interpreted as showing that the sea water that contains the Fukushima radioisotopes has yet to reach our coastline,” Manley said.
Modelers project that the contaminated sea water will arrive on the West Coast sometime this year. The initial results will serve as a baseline for the next two sampling periods scheduled for July and October.
Kelp Watch 2014 was started, in part, “so the public would know that someone is concerned, and that somebody is attempting to measure the arrival of these materials along the West Coast,” Manley said.
He and Vetter can measure radioactivity in the water by using kelp. Radioactivity is more detectable in kelp because the absorbent tissue concentrates the isotopes considerably, Manley said.
Manley and his team are especially concerned with finding the isotope cesium-137, a form of cesium that is radioactive and dissolved in the sea water. If Manley’s team were to detect cesium-137 in the kelp, it would indicate that the surrounding water had been contaminated– specifically from the incident at the Fukushima plant.
In the North Pacific, currents run clockwise at only about 3 mph. It will have taken three years for the contaminated water to arrive to the Pacific Coast.
“During that very slow and long process, a lot of things occur that diminish the amount of radioactivity,” Manley said. “The isotopes decay, and there’s a lot of mixing that occurs, so it becomes very dilute.”
Manley said he’s not too worried about the amount of contamination that will arrive on the coast this year in the sea water.
“The public was concerned because they weren’t hearing anything from our government about the radioactivity that had spilled into the ocean,” Manley said. “When there is a lack of information, people tend to get worried, or worse, start making up information.”
The research team, made up of more than 50 researchers and organizations, volunteering their time and equipment, took 38 samples from different locations along the Pacific Coast. Each sample weighs about 14 pounds and takes 24 hours to analyze.
In addition to the next two sampling periods, Manley will be receiving monthly samples from sites in Canada because the models project that radiation will hit the northwest first.
In the meantime, Manley’s response to his worried friends was to “have a good summer,” and if they were still concerned, they could visit kelpwatch.berkeley.edu to learn what the researchers are finding.
“I don’t know. We’ll wait and see,” Manley said. “That’s why we’re doing this. We want to see what we find. If the levels remain as small as we see right now, there is no human health risk whatsoever.”