Toronto, ON (AHN ) - Albacore tuna packaged in tins could be a health risk from excess mercury according to a warning by Health Canada on Monday.

Health Canada and the Canadian Food Inspection Agency collected random samples of tuna cans over a number of years and found that while many were below dangerous levels of mercury, some tins exceeded the agencies' guidelines.

Albacore tuna is most at risk to have high levels of mercury in the fish, while light tuna fish like skipjack, yellowfin and tongol all typically have lower levels of mercury in the fish.

CBC commissioned their own study and found that in the 60 cans of random tuna brands tested, 13 per cent had mercury levels far above government guidelines.

A "safe" level of mercury is less than .5 ppm according to tuna tin packaging.

The new Canada Food Guide recommendations were released by Health Canada say pregnant women should not have more than two cups of tuna a week while children should be limited to about a half cup each week.

However, health experts say very large amounts of tuna would have to be consumed for any adverse effect from mercury poisoning.

Mercury gets into the human food supply through wastewater being emptied into lakes or through fertilizer run-off - fish then absorb the mercury and enter into the food chain.

Mercury poisoning effects can include DNA alteration, intestinal damage, kidney failure, madness and sometimes even death.

The Canadian Food Inspection Agency will continue to monitor the contents of tinned meat going forward.