contamination
noun /kənˌtæmɪˈneɪʃn/
  /kənˌtæmɪˈneɪʃn/
 [uncountable]- the process or fact of making a substance or place dirty or no longer pure by adding a substance that is dangerous or carries disease synonym adulteration- radioactive contamination
- bacterial/chemical contamination
- Environmental contamination resulting from human activities is a major health concern.
 
- (formal) the act of influencing people's ideas or attitudes in a bad way- They feared cultural contamination from the influx of tourists.