Environmental Engineering Reference
In-Depth Information
Offi cially, the EPA, the U.S. Centers for Disease Control and
Prevention (CDC), and the Council of State and Territorial Epi-
demiologists collaborate to collect information on waterborne dis-
ease outbreaks—what they refer to as WBDO—across the country.
According to a 2006 report from the group, between 1991 and
2002, “an estimated 403,000 persons became ill, 4,400 persons were
hospitalized, and 50 persons died” as a result of waterborne dis-
eases. Among the causes of WBDOs that the report cites are water
distribution systems' defi ciency, untreated groundwater, defi ciency
in water treatment, and “unknown.”
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TWENTY- FIRST CENTURY REALITY
Whatever may be the cause of reported and unreported illnesses
from water supplies, one thing is clear. Those antiquated water de-
livery systems and outdated water treatment plants mentioned in
Chapter 3 contribute to more ills than wasted water down the drain.
Aging pipes (see Figure 4.1) that break can allow contaminants that
breed bacteria into the water. Out-of-date water treatment facilities
may combat most of the parasites and bacteria, but they don't nec-
essarily work with twenty-fi rst-century contaminants like pesticides,
industrial chemicals, and pharmaceuticals. Both man-made and natu-
rally occurring contaminants can end up in source water, too. (
Source
water
refers to the origin of the water that comes out of your tap; it
could be a shallow or deep aquifer, a river, a lake, an ocean, or any or
all of these.)
What Can Contaminate Water Sources?
The EPA suggests some of the ways in which water sources like aqui-
fers, lakes, rivers, and streams can be contaminated.
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Microbial contaminants:
These include bacteria and viruses
that can come from animal waste, sewage treatment plants,
and septic systems.
Inorganic contaminants:
These include metals and salts and
can occur naturally or from storm water runoff in urban
areas, wastewater discharge, oil and gas production, mining,
or farming.
