Small amounts of radioactivity from the Fukushima Daiichi nuclear power plant accident in 2011 have been detected in seawater samples off Canada’s Vancouver Island. It was the first time such radioactive chemicals were found along the North American coast.
Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution or WHOI, said radioactive cesium isotopes cesium-134 and cesium-137 were found in the seawater samples collected on Feb. 19, 2015. The sample gathering occurred at a dock in Ucluelet in a town on the west coast of Vancouver Island, British Columbia. But the amounts were well below internationally established levels of concern to humans and marine life.
The WHOI scientists has been collecting samples over the past 15 months at over 60 sites along the US and Canadian West Coast as well as Hawaii for traces of radioactive isotopes from Fukushima. Their first detectable radioactive sample was taken 100 miles (150 km) off shore of Northern California. Still, the beaches or shorelines accessible to the public remain radiation free. The WHOI has been doing the sampling since 2013 with the help of citizen volunteers.
"Radioactivity can be dangerous, and we should be carefully monitoring the oceans after what is certainly the largest accidental release of radioactive contaminants to the oceans in history," Buesseler said. "However, the levels we detected in Ucluelet are extremely low."
Jay Cullen, University of Victoria chemical oceanographer, told AP the sample was the first collected in North America. “We have seen this contaminated plume of sea water, but offshore. This is the first time we've actually seen it at the shoreline," he said. Ucluelet is over 4,700 miles away from Japan.
The Ucluelet sample contained 1.4 Becquerels per cubic metre (Bq/m3) of cesium-134 and 5.8 Bq/m3 of cesium-137. It was the same levels detected in the samples found 100 miles off the coast of Northern California last summer, WHOI said.
Scientists said they had expected the radioactive water from Japan to arrive on North American shores this year. "We expect more of the sites will show detectable levels of cesium-134 in coming months, but ocean currents and exchange between offshore and coastal waters is quite complex," Buesseler said. "Predicting the spread of radiation becomes more complex the closer it gets to the coast."
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