found in food, water, air, and soil, people may be exposed to high levels of aluminum when they:
- Drink or ingest substances containing high levels of aluminum
 - Breath aluminum dust in workplace air
 - Live where aluminum is mined or processed
 - Live near certain hazardous waste sites
 - Live where aluminum is naturally high
 
the amount of aluminum that foil contributes to your diet is likely insignificant.
See more info from this site
https://www.healthline.com/nutrition/aluminum-foil-cooking
and
http://www.winchesterhospital.org/health-library/article?id=164929