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Chernobyl disaster

Tiny amounts of Fukushima radiation found in California

Laura Mandaro
USA TODAY Network

SAN FRANCISCO — Very small amounts of radiation from the 2011 meltdown at Japan's Fukushima nuclear plant have been detected off the California coast, a scientist who has been monitoring the fallout said this week.

This image shows the damaged No. 4 unit of the Fukushima Dai-ichi nuclear complex in Okumamachi, northeastern Japan, on Tuesday March 15, 2011. White smoke billows from the No. 3 unit.

Ken Buesseler, a senior scientist at the Woods Hole Oceanographic Institution, said trace amounts of telltale radioactive compounds were found 100 miles west of the northern California town of Eureka. Buesseler's crowd-funded monitoring project has been taking ocean samples along the coast of California, Alaska and Canada.

The blast and collapse of the Fukushima Daiichi Nuclear Power Plant as a result of a devastating earthquake and tsunami in March 2011 released cesium-134 at unprecedented levels. This and other radioactive elements have been slowly making their way across the Pacific Ocean, becoming diluted as they go.

The meltdown of three core reactors at the Fukushima plant amounted to the largest nuclear disaster since Chernobyl. The plant, located on Japan's eastern coast, began releasing radioactive material in the surrounding waters. Scientists know that any cesium-134 in coastal waters comes from Fukushima because the element doesn't occur naturally in the environment and didn't exist in the Pacific before the disaster.

But the levels of radioactive elements off U.S. coastal waters shouldn't keep beach-goers from enjoying the surf. In technical terms, the amount of cesium-134 reported in the data is less than 2 Becquerels per cubic meter. That means it's more than 1,000 times lower than the acceptable limits in drinking water set by the U.S. Environmental Protection Agency.

With a tsunami warning in effect for Northern California on March 11, 2011, two men watch the waves at San Francisco's Ocean Beach. The warnings came after a 8.9-magnitude earthquake struck Japan.

"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," said Buesseler, who was scheduled to present the group's findings to the Society of Environmental Toxicology and Chemistry conference in Vancouver Thursday. He also answered reader questions on Reddit Monday.

Previously, scientists have detected Fukushima radiation in tuna along the West Coast, presumably because the fish passed through the radioactive plume along their journey.

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