Above: Fukushima workers in 2013, visitors and workers are required to wear protective suits and masks at Japan‘s Fukushima nuclear power plant, which was rocked by the March 11, 2011 tsunami and earthquake.
Note: There are some conflicting opinions about the danger of this plume on the US west coast. The article below minimizes those risks. But, a nuclear expert who we have a lot of respect for, Arnie Gunderson, has a different view:
Arnie Gundersen, Fairewinds chief engineer: For the people in Japan and people on the West Coast there is a wedge of radioactivity working its way across the Pacific — called a plume — of cesium-137, strontium, and other isotopes. The plume is about a year away from hitting the coast of the Pacific Northwest.
It’s not over, it’s not like it’s going to hit and go away. The nuclear plant is continuing to leak. That plume is 10 times more radioactive than the ocean was before (cesium in the ocean from bomb testing was the only source of radioactivity) and now it’s 10 times that — and likely to grow — because the Daiichi site is going to continue to leak into the environment for years to come.
UPI: Fukushima plume to reach U.S. West Coast in months; Measurable increase in radioactive material — Study: Prolonged exposure for California lasting 10 years; Hits Hawaii early 2014… may already be surrounded
UPI, Aug. 28, 2013: Fukushima radioactive plume being tracked toward U.S. West Coast […] The radioactive plume from the 2011 Fukushima nuclear disaster will reach U.S. shores within 3 years of the date of the incident, Australian researchers say. […] “Observers on the West Coast of the United States will be able to see a measurable increase in radioactive material three years after the event,” researcher Erik van Sebille said in an ARC release Wednesday. “However, people on those coastlines should not be concerned as the concentration of radioactive material quickly drops below World Health Organization safety levels as soon as it leaves Japanese waters.” […]
Phys.org, Aug. 28, 2013: […] [Eddies and giant whirlpools] direct the radioactive particles to different areas along the US west coast. “Although some uncertainties remain around the total amount released and the likely concentrations that would be observed, we have shown unambiguously that the contact with the north-west American coasts will not be identical everywhere,” said Dr Vincent Rossi. “Shelf waters north of 45°N will experience higher concentrations during a shorter period, when compared to the Californian coast. […] The plume will be forced down deeper into the ocean toward the subtropics before rising up again along the southern Californian shelf.” […] Eventually over a number of decades, a measurable but otherwise harmless signature of the radiation will spread into other ocean basins, particularly the Indian and South Pacific oceans. […]
Abstract of Multi-decadal projections of surface and interior pathways of the Fukushima Cesium-137 radioactive plume, October 2013 (print): […] The simulations suggest that the contaminated plume would have been rapidly diluted below 10,000 Bq/m3 by the energetic Kuroshio Current and Kurushio Extension by July 2011. Based on our source function of 22 Bq/m3, which sits at the upper range of the published estimates, waters with Cs-137 concentrations >10 Bq/m3 are projected to reach the northwestern American coast and the Hawaiian archipelago by early 2014. Driven by quasi-zonal oceanic jets, shelf waters north of 45°N experience Cs-137 levels of 10–30 Bq/m3 between 2014 and 2020, while the Californian coast is projected to see lower concentrations (10–20 Bq/m3) slightly later (2016–2025). This late but prolonged exposure is related to subsurface pathways of mode waters, where Cs-137 is subducted toward the subtropics before being upwelled from deeper sources along the southern Californian coast. The model suggests that Fukushima-derived Cs-137 will penetrate the interior ocean and spread to other oceanic basins over the next two decades and beyond. […]