Scientists are keeping a watch on the radioactive plume of water from Fukushima as it reaches west coast of North America.
The full scale of the effect of the plume should be known in the next two months.
Till now, only small traces of pollution from the Japanese power plant have so far been recorded in Canadian continental waters.
This, however, will increase as contaminants disperse eastwards on Pacific currents, the BBC reported.
But scientists stress that even peak measurements are going to be well within the limits which have been set by safety authorities.
Although the radioactivity concentration is low - less than one becquerel per cubic metre of water - they have allowed the scientists to start validating the two models being used to forecast the probable future progression of the plume.
One of these models anticipates a max concentration by mid-2015 of up to 27 becquerels per cubic metre of water; the other suggests no more than about two becquerels per cubic metre of water.
