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Scientists dismiss tsunami trash radiation worries for Alaskans

Ben Anderson
Debris float in the Pacific Ocean off the coast of Japan after an earthquake and subsequent tsunami struck the nation on March 11.
U.S. Navy photo
An aerial view of debris from an 8.9 magnitude earthquake and subsequent tsunami that struck northern Japan.
U.S. Navy photo
This figure shows the probable pathways of the debris that entered the ocean on March 11, 2011, as estimated from historical trajectories of drifting buoys
Nikolai Maximenko, International Pacific Research Center
Japanese tsunami debris on the open ocean, March 2011.
U.S. Navy photo

In the wake of last year's earthquake and resulting tsunami in Japan, a huge patch of flotsam washed into the Pacific Ocean has been drifting toward the U.S. Some debris has already washed ashore on Washington state's Olympic Peninsula and Alaska's Kodiak Island. One big concern for coastal dwellers has been whether the oncoming deluge of detritus contains radioactivity caused by the Fukushima nuclear plant's meltdown. 

Now a group of nuclear radiation health experts from Oregon State University are assuaging some of the public's fears with a dismissal of any residual radioactivity among the debris.

Nearly one year ago, a magnitude 9.0 earthquake struck offshore in Japan, and the resulting drama surrounding the potential -- and then reality -- of a meltdown at the Fukushima nuclear power plant seized the world's attention. Radiation releases following the meltdown could be detected in many places worldwide, including U.S. shores, but  the levels dropped off sharply within about 10 days of the earthquake.

A month later, a new worry arose. The International Pacific Research Center was reporting that a huge patch of flotsam was making its way west, and predicted that the bulk of the detritus would arrive around 2014. That prediction has since been revised, and you can see a nifty animation of the latest data here.

In a press release, OSU scientists said that residual radiation is unlikely. "...The minor amounts of (radioactive) deposition on the debris field scattered in the ocean will have long since dissipated, decayed or been washed away by months of pounding in ocean waves," the release said.

Which is probably a good thing, considering some debris washed ashore back in December on Alaska's Kodiak Island. In that instance, the debris -- floats from Japanese oyster farms -- were identified by a Washington-state oceanographer, and the National Oceanic and Atmospheric Administration said that the floats could indeed be from the March 2011 tsunami.

At the time, a scientist with the NOAA Marine Debris Division said that the agency encouraged local beachcombers to report any unusual findings, in hopes of gathering additional data about the spread and movement of the debris. Kathryn Higley,head of the Department of Nuclear Engineering and Radiation Health Physics at OSU, warned that even though the debris isn't radioactive, it isn't necessarily safe.

"If you see something on the beach that looks like it may have come from this accident, you shouldn’t assume that it’s safe," Higley said. "People should treat these debris with common sense; there could be some things mixed in there that are dangerous. But it will have nothing to do with radioactive contamination."

Based on recent findings, public concern over excess levels of radiation washing ashore with the debris was largely unfounded. "There are a lot of misconceptions about radioactivity," Higley said. "Many people believe that if it can be measured, it’s harmful. But we live in a world of radiation coming to us from the sun, or naturally present in the earth, or even from our own bodies."

The scientists noted that the airborne levels of radiation released to distant areas was less than a person would receive from a typical X-ray. The OSU findings reflect Alaska officials' assurances that the debris poses little threat of radioactive contamination.

"From what we found from the data that is available, the answer is no," Kristin Ryan, environmental health director for the Alaska Department of Environmental Conservation told the Juneau Empire in January. "There is no concern to us that there’s any radiation impacts in Alaska."

Most of the trash won't reach shore anyway: According to predictions from the International Pacific Research Center, 95 percent of the flotsam will join other floating trash in the Great Pacific Garbage Patch, a "convergence zone" north of Hawaii where ocean currents deposit much marine debris.

NOAA continues to track the movement of the debris, along with the Marine Conservation Alliance, recording instances of debris washing ashore in Alaska. Anyone who comes across what they believe might be tsunami trash are encouraged to contact NOAA at disasterdebris@NOAA.gov.

Contact Ben Anderson at ben(at)alaskadispatch.com