### Question
How is the "contaminant" defined?


### Answer
The term **contaminant** is defined in *15 U.S.C. § 8951* as follows -

> any physical, chemical, biological, or radiological substance or matter in water

#### Citation:
  - *15 U.S.C. § 8951*
  - Heading: **CHAPTER 115-PERFLUOROALKYL AND POLYFLUOROALKYL SUBSTANCES AND EMERGING CONTAMINANTS > SUBCHAPTER IV-EMERGING CONTAMINANTS**

