Health Canada has detected a "minuscule" increase in radiation levels in this country, further evidence that the fallout from the disaster at Japan's nuclear power plant has reached North America.
However, the agency stressed that the amount of radioactivity released into this country's environment from the crippled Fukushima Daiichi reactors is too small to pose a health risk to Canadians.
A five-hour airplane flight from Montreal to Vancouver exposes an individual to 50,000 times more radiation than the level detected in Canada as a result of the stricken reactors in Japan, Health Canada said, adding that such a flight does not pose any health risks.
The agency initially detected on March 18 that some radioactive material had travelled thousands of kilometres from Japan to Canada's west coast. It was forced to issue a news release on Tuesday after opposition members raised the matter in the Ontario legislature during Question Period.
France Gélinas, health critic for the New Democrats, asked if government officials were testing the province's milk supply for radiation levels. Energy Minister Brad Duguid accused Ms. Gélinas of "fearmongering" and did not answer the question.
In fact, the government began weekly testing for radiation levels in milk shortly after March 11, when a magnitude 9.0 earthquake struck off the northeast coast of Japan, killing more than 13,000 people and crippling the Fukushima plant.
The Ministry of Labour's Radiation Protection Services has also increased the frequency of testing to weekly from monthly of drinking water, precipitation, air particulate and seasonal fruits and vegetables, said spokesman Greg Dennis.
To date, he said, tests have shown no increases in the acceptable amount of radioactive isotope iodine-131.
Concern mounted over whether the food supply in Ontario has become tainted after the Environmental Protection Agency in the United States reported last weekend that milk from Little Rock, Ark. and drinking water from Philadelphia contained the highest levels of Iodine-131 from Japan yet detected.
Mr. Duguid acknowledged to reporters that there has been "some minor increase" in radiation in the province.
"At this point in Ontario," he said, "there's nothing to suggest that there's any cause for concern in terms of radiation levels."
The province's Chief Medical Officer of Health, Dr. Arlene King, also issued a statement, saying there is no health risk to Ontarians from Fukushima, where the radiation in the water, air and soil around the four reactors is thousands of times the legal limit.
Canadians are routinely exposed to naturally-occurring radiation in the environment from rocks and soil - the average person is exposed to between two and three millisieverts a year. Canadians are also exposed to artificial sources of radiation - a CT scan can expose a person to between 5 and 30 millisieverts. And chronic exposure over long periods can increase a person's risk of cancer.
New Democrat Leader Andrea Horwath told reporters it is surprising that her party could not get answers from government officials during Question Period.
"This is not a new issue," she said. "I was quite shocked to learn that the government doesn't seem to be on the ball when it comes to this issue."