In March 2011, a massive earthquake and tsunami triggered multiple nuclear meltdowns at Japan's Fukushima Daiichi nuclear power plant. A massive cloud of radiation was ejected into the atmosphere, settling all across Japan and into the Pacific Ocean.
Approximately 800 terabecquerels' worth of cesium-137 (Cs-137) alone is expected to reach North America by next year, accounting for just 5 percent of the Cs-137 spilled into the ocean as a result of the disaster.
Radioactivity already arriving
Radioactive cesium does not naturally occur on planet Earth and is found only as a result of human nuclear activities. Cs-137 is widely considered one of the most dangerous byproducts of nuclear activity, because it mimics the activity of potassium and therefore accumulates in soil and plants, and is actively taken up by the human body.Aoyama says that approximately 3,500 terabecquerels' worth of Cs-137 have been released into the sea from the Fukushima plant since March 2011, plus an additional 1.2 to 1.5 terabecquerels that was first released into the air but later fell into the sea. Based on measurements of the pace at which the Cs-137 has been moving eastward, Aoyama recently calculated that 800 terabecquerels would reach the West Coast of North America by next year.
Notably, 800 terabecquerels is nearly as much as (80 percent of) the 1,000 terabequerels that Fukushima operator Tokyo Electric Power Company says fell over Japan following the disaster.
In April, researchers from Woods Hole Oceanographic Institution announced that they had detected traces of Cs-134 in waters collected at the shores of Vancouver Island. Because this isotope has a half-life of only two years, the only likely source of this contamination is from the Fukushima disaster.
Based on this and other studies, Aoyama said that the 800 terabecquerels he has predicted might already have arrived at North American shores.""
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