Can marijuana be in the system from passive use?

Depends on how much "passive use" is. If you use it 1-2 times a month and are in moderately good health condition and diet it should not be in your system for more than a couple days after use. If you use 1-2 times a week there is a solid chance that it will be in your system and be able to detected up to 30 days after non use, however, if you work out on a regular basis and keep yourself in good physical condition it will be out of your system in half the time depending on your body characteristics (Body fat percentage mostly).