The devastating quake in Japan in 2011 damaged a Fukushima nuclear reactor. However, the effect was also felt in the U.S as the radiation apparently reached the Pacific.

According to New York Post report, researchers discovered and collected a radioactive element called cesium-134 in seawater samples in Tillamook Bay and Gold Beach, Oregon. However, the levels of an isotope form called cesum-134 is still extremely low and don't harm humans and the environment. Ken Buesseler, a senior scientist at Woods Hole Oceanographic Institution also said people don't have to worry about swimming in and consuming fish from the West Coast. 

Cesum-134 has also been known as the fingerprint of Fukushima.

In 2011, Japan was hit by a 9.0-Richter scale earthquake that killed hundreds of people. In addition, the quake also heavily damaged Fukushima Daiichi nuclear power plant.  The catastrophe discharged some radioactive isotopes - including the lethal products of cesium-137 and iodine-131 - that polluted  the air and water. The radiation later spoiled the ocean.

However, for the first time, Cesum-134 was also spotted in a Canadian salmon, as reported by the Fukushima InFORM project. The research was  led by  chemical oceanographer Jay Cullen from the University of Victoria.

Samples from Oregon were obtained in last winter (January and February of 2016) and then were analyzed, quoted by Statesman Journal.  Each measured 0.3 becquerels per cubic meter of cesium-134. 

Previously, Buesseler and his colleagues spotted the isotope in a seawater sample taken from a dock on Vancouver Island, B.C.

While Cullen is in charge of the InFORM project to figure out radiological risk posed to that country's oceans as the impact of the nuclear disaster. InFORM project involves  some academic government and non-profit institutions, including Woods Hole. 

Cullen's team reported in summer of 2015 that a single sockeye salmon was contaminated by cesum-134. The salmon was taken from Okanagan Lake.

Based on this occurrence, researchers can conclude that it may take four to five years from the radiation to affect the U.S West Coast.