Pollution vs. contamination

English makes a distinction between the words pollution and contamination. Pollution is the introduction of harmful substances or products into the environment. It is the act or process of polluting or the state of being polluted, especially the contamination of soil, water, or the atmosphere by the discharge of harmful substances. Something that pollutes; a pollutant or a polluting agent: Pollution in the air reduced the visibility near the airport.

Contamination is the presence of extraneous, especially infectious, material that renders a substance or preparation impure or harmful. Contamination does not necessarily have to be introduction of harmful substances or products into the environment. For example, you can say: The lab is contaminated with radioactive substance. But you wouldn't say: The lab is *polluted with radioactive substance.

Contamination is the condition of food and/or water made unfit for consumption by humans or animals because of the presence of environmental chemicals, radioactive elements, bacteria or organisms, the byproduct of the growth of bacteria or organisms, decomposing material (to include the food substance itself), or waste in the food or water: Contamination of the water supply. Also, a surgical suite could be contaminated simply because someone walks into it when they're not sterile.