Fukushima Radiation: Higher Measurements off West Coast, Researchers Say

Higher measurements of radiation from the Fukushima nuclear meltdown have been found in the ocean off the U.S. west coast recently. One of these was a sample from 1,600 miles west of San Francisco, which had a level of radioactive cesium isotopes that is 50 percent higher than samples collected so far off the west coast. That said, at 11 Becquerel's per cubic meter of seawater (264 gallons or so), it is still 500 times lower than U.S. government safety limits that pertain to drinking water, and it is also under the limits of concern for contact by swimmers, boaters or others engaged in recreational activities.

One of the earlier researchers to begin monitoring the radiation was Ken Buesseler, with Woods Hole Oceanographic Institution (WHOI). He organized an expedition to the Northwest Pacific near Japan about three months after the nuclear accident, which had started in March 2011. He launched a citizen-science sampling effort, Our Radioactive Ocean, in 2014 and used sensors to find minute levels of radioactivity in the ocean. More than 110 new samples have been added in 2015, plus the 135 that were previously collected, according to a release.

"These new data are important for two reasons," Buesseler said in the release. "First, despite the fact that the levels of contamination off our shores remain well below government-established safety limits for human health or to marine life, the changing values underscore the need to more closely monitor contamination levels across the Pacific. Second, these long-lived radioisotopes will serve as markers for years to come for scientists studying ocean currents and mixing in coastal and offshore waters."

Other researchers on the project involve the group Kelp Watch and a team of Canadian scientists with the name InFORM. The InFORM team has also sampled fish and hasn't seen Fukushima cesium in British Columbia fish.
"Levels today off Japan are thousands of times lower than during the peak releases in 2011. That said, finding values that are still elevated off Fukushima confirms that there is continued release from the plant," Buesseler said in the release.

Buesseler will talk about latest findings regarding the spread of Fukushima radiation at the American Geophysical Union conference on Dec. 14, 2015.

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