Japan’s Fukushima catastrophe brings big radiation spikes to B.C., Georgia Straight (Vancouver) by Alex Roslin, August 4, 2011:
After Japan’s Fukushima catastrophe, Canadian government officials reassured jittery Canadians that the radioactive plume billowing from the destroyed nuclear reactors posed zero health risks in this country.
In fact, there was reason to worry. Health Canada detected massive amounts of radioactive material from Fukushima in Canadian air in March and April at monitoring stations across the country.
The level of radioactive iodine spiked above the federal maximum allowed limit in the air at four of the five sites where Health Canada monitors levels of specific radioisotopes. […]
Monitoring stations catch a fraction of Fukushima fallout, Georgia Straight (Vancouver) by Alex Roslin, August 4, 2011:
[…] You have to scroll down to the bottom of Health Canada’s radiation webpage to find the more striking data from the five stations monitoring specific radioactive substances.
This data shows the air at the five stations contained an average of 33.3 millibecquerels of radioactive iodine per cubic metre during 30.4 days of elevated radiation.
That works out to double the 16.7 millibecquerels per cubic metre of iodine-131 that would be permitted over those 30.4 days, according to the maximum limit set by the Canadian Nuclear Safety Commission. (The commission’s ceiling is 200 millibecquerels per cubic metre of exposure in the air on a daily basis for an entire year. That equates to 16.7 millibecquerels per cubic metre over 30.4 days.)
The station in Sidney, B.C., detected 19.4 millibecquerels per cubic metre of iodine-131 in the air during a 22-day-long spike in radiation. That was 61 percent higher than the maximum dose of 12.1 millibecquerels per cubic metre permitted for 22 days.