Cross-contamination occurs when gluten-free foods come into contact with foods that contain gluten. It can happen during the manufacturing process, for example, if the same equipment is used to make a variety of products. Some food labels include a may contain statement if cross-contamination is likely.
After getting a tattoo, swimming must be avoided until the skin has stopped peeling and all scabs have fallen off. For most people, this means waiting a minimum of two weeks.
It must be healed before you even think about getting in the water. Tattoos take anywhere from two weeks to a months to heal, it can be longer though. Color should not effect healing. If you can't stay out of the water for that long, wait until the following fall to get the tattoo, that way you won't have to miss out.