It took just over two years for the radioactive plume from Fukushima, Japan, to travel via ocean currents and reach the shores of North America, researchers say.
A radiation plume from the March, 2011 nuclear accident in Fukushima, Japan took about 2.1 years to travel via ocean currents and ultimately cross the waters of the Pacific Ocean to reach the shores of North America. That’s according to to a study published at the end of 2014 (December 29) by the Proceedings of the National Academy of Sciences,
Following the March 11, 2011 magnitude 9.0 earthquake and resulting tsunami in the Pacific Ocean, the Fukushima Daiichi nuclear power plant released cesium 134 and cesium 137 into the ocean. Researchers knew that a small percentage of this radioactive material would be carried by currents across the Pacific, eventually reaching the west coast of North America.
Computer models could predict when this might happen, but by taking actual samples of the ocean water and testing them for cesium 134 and cesium 137 the scientists could see for certain when it happened.
John Smith, a research scientist at the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, is the lead author of the newly published paper. Smith said in a press release:
We had a situation where the radioactive tracer was deposited at a very specific location off the coast of Japan at a very specific time. It was kind of like a dye experiment. And it is unambiguous – you either see the signal or you don’t, and when you see it you know exactly what you are measuring.
Full article: Tracking Fukushima radiation across the Pacific (EarthSky)