TOKYO, April 30 (Xinhua) -- About 800 tera becquerel of Cesium- 137 is going to reach West Coast of North America by 2016, equivalent to 5 percent of the total Cs-137 amount discharged to the pacific ocean after the Fukushima nuclear disaster, a Japan researcher was quoted by Kyodo recently.
Michio Aoyama, a professor from Japan's Fukushima University Institute of Environmental Radioactivity said about 3,500 tera bq of Cs-137 have been released to the sea and 1.2 to 1.5 tera bq of Cs-137 released to the air, then fell to the sea from the crippled nuclear plant.
Part of the radioactive substances have been observed to move eastward at a speed of 7 kilometers and 3 kilometers one day before March and August 2012 respectively, Aoyama said.
However, Cs-137 levels detected at U.S. beaches were 1 to 2 bq per cubic meter, much lower than the safety limit for cesium levels in drinking water by the World Health Organization.
"Even if all the 800 tera bq Cs-137 have arrived, the radiation levels will stay at relatively low level that aren't expected to harm human health," said Aoyama.
The Woods Hole Oceanographic Institution of America has announced early April that they detected Cs-134 for the first time in a seawater sample from the shoreline of North America. Cs-134, with a half-life of only two years, is an unequivocal marker of Fukushima ocean contamination, said researchers.