Pollutant

**Semantic type:** Hazardous or Poisonous Substance

**Definition:** Any chemical compound, biological object, physical factor in a concentration or amount that adversely alters the physical, chemical, or biological properties of the environment. The term includes pathogens, toxic metals, carcinogens, oxygen-demanding materials, radiation, natural substances, synthetic industrial chemicals, biocides and all other harmful substances and factors. (NCI)