From a quick search on the TC website:
.... many pilots in Canada may have misconceptions about Canadian Aviation Regulation (CAR) 602.03, the rule that addresses the consumption of alcohol. Here it is: 602.03 No person shall act as a crew member of an aircraft
within eight hours after consuming an alcoholic beverage;
while under the influence of alcohol; or
while using any drug that impairs the person's faculties to the extent that the safety of the aircraft or of the persons on board the aircraft is endangered in any way.
We often refer to this as the "8 hours from bottle to throttle" rule, but if we look at it closely, we see that it is a three-part regulation. What some may be overlooking is the second part that states, "No person shall act as a crew member of an aircraft (b) while under the influence of alcohol." Transport Canada has no tolerance on this rule if you are found with any trace of alcohol in your system. The regulation can actually be misleading; one rule states that you are allowed to drink eight hours before a flight, while the other says you better not get caught with any trace of alcohol in your system even if it has been eight hours since your last drink.
source
That's a 2005 document, but i doubt TC have softened their stance ... it sounds like "zero" is the position in that extract.