"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, referring to the Fukushima disaster, the world's worst nuclear power plant accident since Chernobyl in 1986.
At the same time, he added that the "levels we detected in Ucluelet are extremely low," which is why he said they do not pose a significant threat to human or marine life.
Buessler said that low cesium levels may finally reach Washington and proceed to California, but added that "predicting the spread of radiation becomes more complex the closer it gets to the coast."
In March 2011, an earthquake-tsunami disaster rocked the Fukushima plant, 130 miles (209 kilometers) northeast of Tokyo, triggering nuclear meltdowns at three reactors and leaking radioactive material into the ocean. More than 160,000 residents have been displaced.