As workers removed a second canopy panel covering the reactor No. 1 building at the Fukushima Daiichi nuclear power plant in Japan Monday, the Woods Hole Oceanographic Institution announced that radioactivity from the plant had been found in trace amounts in water samples taken 100 miles off the coast of Northern California.
The amounts of radiation found parallel with the Northern California city of Eureka was at levels 1,000 times lower than is permitted in drinking water by U.S. standards. In a release, the Woods Hole Institution said the amount of cesium-134 was “detectable only by sophisticated equipment able to discern minute quantities of radioactivity.”
A radioactive plume of water has traveled across the Pacific after massive amounts of radioactive water was released during the March 2011 earthquake and tsunami event that crippled the six-reactor facility in northeastern Japan.
The research center, which is based in Massachusetts, said radioactivity in Japanese waters just after the March 2011 event was “more than 10 million times” higher than the level found in a crowd-funded trip from Dutch Harbor, Alaska to Eureka taken this summer on the research ship Point Sur.
Cesium-134 has a half life of two years and does not occur naturally. “Therefore the only source of this cesium-134 in the Pacific today is from Fukushima,” said marine chemist Ken Buesseler.
Out of 50 water samples collected, 20 have been processed and 10 were positive for cesium-134 at a level less than 2 Becquerels per cubic meter. This is “far below where one might expect any measurable risk to human health or marine life according to international health agencies,” the Woods Hole Institution said in a release.
In Japan, workers removed a second canopy panel from the cover placed in October 2011 over the reactor unit 1 building, which was rocked by an hydrogen explosion on March 12, 2011, one day after the devastating earthquake.
The first panel was removed Oct. 31. Technicians have been monitoring the area for increased radioactivity, while workers have been spraying the area with a resin intended to keep dust in place in preparation for continued clean up work.
The roof is not expected to be removed completely until March 2015, Asahi Shimbun reported.