Environmental Engineering Reference
In-Depth Information
TAble 3.3
National Secondary Drinking Water Standards
Contaminant
Suggested Levels
Contaminant Effects
Aluminum
0.05-0.2 mg/L
Discoloration of water
Chloride
250 mg/L
Salty taste, corrosion of pipes
Color
15 color units
Visible tint
Copper
1.0 mg/L
Metallic taste, blue-green staining of porcelain
Corrosivity
Noncorrosive
Metallic taste, fixture staining, corroded pipes
(corrosive water can leach pipe materials,
such as lead, into drinking water)
Fluoride
2.0 mg/L
Dental fluorosis (a brownish discoloration of
the teeth)
Foaming
agents
0.5 mg/L
Aesthetic: frothy, cloudy, bitter taste, odor
Iron
0.3 mg/L
Bitter metallic taste, staining of laundry, rusty
color, sediment
Manganese
0.05 mg/L
Taste, staining of laundry, black to brown color,
black staining
Odor
3 threshold odor number
Rotten egg, musty, or chemical smell
pH
6.5-8.5
Low pH—bitter metallic taste, corrosion
High pH—slippery feel, soda taste, deposits
Silver
0.1 mg/L
Argyria (discoloration of skin), graying of eyes
Sulfate
250 mg/L
Salty taste, laxative effects
Total dissolved
solids (TDS)
500 mg/L
Taste, possible relation between low hardness
and cardiovascular disease, indicator of
corrosivity (related to lead levels in water),
damage to plumbing, limited effectiveness of
soaps and detergents
Zinc
5 mg/L
Metallic taste
Source: USEPA, Fact Sheet: National Secondary Drinking Water Standards , U.S. Environmental
Protection Agency, Washington, DC, 1991; USEPA, Is Your Drinking Water Safe? U.S.
Environmental Protection Agency, Washington, DC, 1994.
in drinking water. A range of concentrations is established for substances
that affect water only aesthetically and have no direct effect on public health.
We present secondary standards in Table 3.3 .
1996 Amendments to SDWA
After more than 3 years of effort, the Safe Drinking Water Act Reauthorization
(one of the most significant pieces of environmental legislation passed to
date) was adopted by Congress and signed into law by President Clinton
on August 6, 1996. The new streamlined version of the original SDWA
gives states greater flexibility in identifying and considering the likelihood
for contamination in potable water supplies and in establishing monitor-
ing criteria. It establishes increased reliance on “sound science” instead of
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