Environmental Engineering Reference
In-Depth Information
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Animal feeding operations
—Nitrogen, bacteria, viruses, phosphates
•
Deicing salts applications
—Chromate, phosphate, ferric ferocyanide,
Na-ferrocyan, chlorine
•
Urban runoff
—Suspended solids and toxic substances, especially
heavy metals and hydrocarbons, bacteria, nutrients, petroleum
residues
•
Percolation of atmospheric pollutants
—Sulfur and nitrogen compounds,
asbestos, heavy metals
•
Mining and mine drainage—
Acids, toxic inorganics (heavy metals),
nutrients (coal); radium, uranium, fluorides (phosphate); sulfuric
acid, lead, cadmium, arsenic, sulfur, cyan (metallic ores)
•
Production wells
—Oil wells (1.2 million abandoned production wells);
farm irrigation wells; installation, operation, and plugging of all wells
•
Construction excavation
—Pesticides, diesel fuel, oil, salt, various others
•
Pharmaceuticals and personal care products (PPCPs)
—Any product
used by individual for personal health or cosmetic reason or used
by agribusiness to enhance growth or health of livestock
Note:
Before we discuss specific water pollutants, we must examine sev-
eral terms important to the understanding of water pollution. One of
these is
point source
. The USEPA defines a
point source
as “any single iden-
tifiable source of pollution from which pollutants are discharged, e.g., a
pipe, ditch, ship, or factory smokestack.” For example, the outlet pipes of
an industrial facility or a municipal wastewater treatment plant are point
sources. In contrast,
non-point sources
are widely dispersed sources and
are a major cause of stream pollution. An example of a non-point source
of pollution is rainwater carrying topsoil and chemical contaminants into
a river or stream. Some of the major sources of non-point source pollution
include water runoff from farming, urban areas, forestry, and construc-
tion activities. The word
runoff
signals a non-point source that originated
on land. Runoff may carry a variety of toxic substances and nutrients, as
well as bacteria and viruses with it. Non-point sources now comprise the
largest source of water pollution, contributing approximately 65% of the
contamination in quality-impaired streams and lakes.
Radionuclides
When radioactive elements decay, they emit alpha, beta, or gamma radia-
tions caused by transformation of the nuclei to lower energy states. In drink-
ing water, radioactivity can be from natural or artificial radionuclides (the
