Contamination

n. pollution, something which contaminates; spreading of impurities; infection (by a disease)

Pollution is the introduction of pollutants (whether chemical substances, or energy such as noise, heat, or light) into the environment to such a point that its effects become harmful to human health, other living organisms, or the environment.
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Contamination /con·tam·i·na·tion/ 1. the soiling or making inferior by contact or mixture. 2. the deposition of radioactive material in any place [more]Contamination - Community and Resources

Noun
1. the state of being contaminated
(synonym) taint
(hypernym) impurity, impureness
(hyponym) dust contamination
(derivation) contaminate
2. a substance that contaminates
(synonym) contaminant
(hypernym) material, stuff
(derivation) contaminate
3. the act of contaminating or polluting; including (either intentionally or accidentally) unwanted substances or factors
(synonym) pollution
(antonym) decontamination
(hypernym) soiling, soilure, dirtying
(hyponym) dust contamination
(derivation) contaminate

n. contamination, infection, pollution