Parameter Tree:
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY > CONTAMINANTS

Definition:
Contaminants are foreign agent that are present, as in water or sediment
which may produce a physical or chemical change.  


Reference:
Rand, Gary M. 1995. Fundamentals of Aquatic Toxicology: Effects, Environmental
Fate, and Risk Assessment. Taylor and Francis. Washington, D.C.