Monterey600pxThree and a half years after the Fukushima nuclear disaster in Japan, trace amounts of radioactivity have been detected off the California coastline. The levels are extremely low and not considered dangerous to people or sea life.

The report was released on Monday, November 10 by scientist Ken Buesseler, a nuclear chemist at the Woods Hole Oceanographic Institution on Cape Cod.

The levels of Cesium-134 were detected in August by volunteers aboard a research vessel from the Moss Landing Marine Laboratory in Monterey. Those samples were taken from waters located about 100 miles west of Eureka and later sent to the Woods Hole Oceanographic Institution on Cape Cod for analysis. The findings confirm a report by scientists in Canada who found similar faint traces in the ocean off British Columbia.

Fortunately, the amounts of radiation measured off California are far lower than an amount known to cause a threat to marine life or humans.

Radioactivity is measured in units called becquerels. The levels of radioactivity in the waters just off Fukushima after the disaster measured in the tens of millions per cubic meter of water. The levels measured in the water off California measured only 2 becquerels per cubic meter – more than 1,000 times lower than levels the U.S. Environmental Protection Agency considers safe in drinking water.

“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” Buesseler said. “It’s not zero, “But it’s not some large, dangerous amount of cesium that might reach our shorelines.”

Cesium-134 decays rapidly, with a two-year half-life. The other isotope found in nuclear weapons and accidents is cesium-137, which has a half-life of 30 years. Cesium-137 from weapons tested during the Cold War can still be detected in the world’s oceans.

No federal government agency finances efforts to track radioactivity in ocean water, so Ken Buesseler, a nuclear chemist at the Woods Hole Oceanographic Institution, has created a volunteer organization, Our Radioactive Ocean, where coastal residents to collect water samples periodically and send them to his lab at Woods Hole. The volunteers collecting water samples along the coast from San Diego to Canada and around Hawaii.

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