Dear EarthTalk: Is there any environmental risk from all that Japanese tsunami debris that is starting to wash up on the U.S. west coast?
— Bailey Thigerson, Seattle, WA
The Japanese government estimates that some 1.5 million tons of debris is afloat in the Pacific Ocean as a result of the March 2011 earthquake, tsunami and nuclear disaster. No one knows exactly how much of this debris will wash up on American shores or end up absorbed by the water column or trapped in mid-ocean gyres, but state coastal authorities from California to Alaska are readying response plans.
One certain threat is invasive species. Scientists from Oregon State University’s Hatfield Marine Science Center confirmed the presence of dozens of species native to Japanese coastal waters—including barnacles, starfish, urchins, anemones, amphipods, worms, mussels, limpets, snails, solitary tunicates and algae—that were on a large floating dock in Japan that washed ashore at Agate Beach near Newport, Oregon in June 2012. According to researchers, the 66 foot long dock contained some 13 pounds of organisms per square foot, and an estimated 100 tons of living matter overall. While there is no evidence to date that anything from the float has established on U.S. shores, researchers fearing the worst but hoping for the best are continuing to monitor the situation.
Of course, what worries researchers more is that the dock may just be the tip of the iceberg, so to speak, in regard to what else might wash ashore. “I think that the dock is a forerunner of all the heavier stuff that’s coming later, and amongst that heavier stuff are going to be a lot of drums full of chemicals that we won’t be able to identify,” says Chris Pallister, president of the non-profit Gulf of Alaska Keeper, a group dedicated to cleaning marine debris from Alaska’s coastline. He worries that the onslaught of debris will be “far worse than any oil spill … or any other environmental disaster we’ve faced on the West Coast” as a result of the sheer amount and variety of debris and the wide geographic scope it is likely to affect.
Officials at the U.S. National Oceanic and Atmospheric Administration (NOAA) believe the Japanese tsunami debris has already spread over an area of the Pacific Ocean roughly three times the size of the contiguous United States. While some of the debris has already made landfall in the U.S., the bulk of it will take several more months to make it across the Pacific. Seattle-based oceanographer Curtis Ebbesmeyer, who has been tracking huge gyres of trash in the ocean for two decades and runs the Beachcombers’ Alert website, thinks the majority of tsunami debris will reach U.S. shores as early as October 2012.
Another concern: Researchers were “startled” to find detectable levels of radioactivity from the Fukushima nuclear disaster in bluefin tuna, a favorite sushi fish, off the coast of California. While the levels of radioactive cesium were some 10 times higher than the amount measured in tuna off California in previous years, it is still below safe-to-eat limits in both Japan and the U.S. The researchers are continuing to study more bluefin tissue samples to see if elevated radiation levels persist, and are also looking into radiation levels in other long distance migratory species including sea turtles, sharks and seabirds.