Glossary - The Drinking Water - page 327

Chlorinated solvent: A volatile organic compound containing chlorine;
some common solvents are trichloroethylene, tetrachloroethylene,
and carbon tetrachloride.
Chlorination: The process of adding chlorine to water to kill disease-caus-
ing organisms or to act as an oxidizing agent.
Chlorine demand: A measure of the amount of chlorine that will combine
with impurities and is therefore unavailable to act as a disinfectant.
Chlorofluorocarbons: A class of volatile compounds consisting of carbon,
chlorine, and fluorine. Commonly called freons , they have been used
in refrigeration mechanisms, as blowing agents in the fabrication of
flexible and rigid foams, and, until banned from use several years
ago, as propellants in spray cans.
Cienaga: A marshy area where the ground is wet due to the presence of
seepage of springs.
Clean Water Act (CWA): Federal law passed in 1972 (with subsequent
amendments) intended to restore and maintain the chemical, physi-
cal, and biological integrity of the nation's waters. Its long-range goal
is to eliminate the discharge of pollutants into navigable waters and
to make national waters fishable and swimmable.
Climate: The sum total of the meteorological elements that characterize
the average and extreme conditions of the atmosphere over a long
period of time at any one place or region of the Earth's surface.
Coagulants: Chemicals that cause small particles to stick together to form
larger particles.
Coagulation: A chemical water treatment method that causes very small
suspended particles to attract one another and form larger particles.
This is accomplished by the addition of a coagulant, which neutral-
izes the electrostatic charges causing the particles to repel each other.
Coliform bacteria: A group of bacteria predominantly inhabiting the intes-
tines of humans or animals but also occasionally found elsewhere.
The presence of these bacteria in water is used as an indicator of
fecal contamination (contamination by animal or human wastes).
Color: A physical characteristic of water. Color is most commonly tan or
brown from oxidized iron, but contaminants may cause other col-
ors, such as green or blue. Color differs from turbidity, which is the
cloudiness of the water.
Combined sewer overflow: The discharge of untreated sewage and storm-
water to a stream when the capacity of a combined storm/sanitary
sewer system is exceeded by storm runoff.
Communicable diseases: Usually caused by microbes —microscopic organ-
isms including bacteria, protozoa, and viruses. Most microbes are
essential components of our environment and do not cause disease.
Those that do are called pathogenic organisms , or simply pathogens .
Community: In ecology, the species that interact in a common area.