usage: make impure; "The industrial wastes polluted the lake"
2. contaminate, change, alter, modify
usage: make radioactive by adding radioactive material; "Don't drink the water--it's contaminated"
1. dirty (vs. clean), contaminating
usage: spreading pollution or contamination; especially radioactive contamination; "the air near the foundry was always dirty"; "a dirty bomb releases enormous amounts of long-lived radioactive fallout"