Environmental Engineering Reference
In-Depth Information
TAble 3.2
Selected Primary Standard MCLs for Inorganic Chemicals
Maximum
Contaminant
Level (MCL)
(mg/L)
Contaminant
Health Effects
Sources
Arsenic
Nervous system effects
0.010
Geological, pesticide residues,
industrial waste, smelter
operations
Asbestos
Possible cancer
7 MFL
a
Natural mineral deposits,
air-conditioning pipe
Barium
Circulatory system
effects
2
Natural mineral deposits, paint
Cadmium
Kidney effects
0.005
Natural mineral deposits, metal
finishing,
Chromium
Liver, kidney, digestive
system effects
0.1
Natural mineral deposits, metal
finishing, textile and leather
industries
Copper
Digestive system effects
TT
b
Corrosion of household
plumbing, natural deposits,
wood preservatives
Cyanide
Nervous system effects
0.2
Electroplating, steel, plastics,
fertilizer
Fluoride
Dental fluorosis,
skeletal effects
4
Geological deposits, drinking
water additive, aluminum
industries
Lead
Kidney, nervous system
effects; toxic to infants
TT
Corrosion of lead service lines
and fixtures
Mercury
0.002 Industrial manufacturing,
fungicide, natural mineral
deposits
Nickel Heart, liver effects 0.1 Electroplating, batteries, metal
alloys
Nitrate Blue-baby effect 10 Fertilizers, sewage, soil and
mineral deposits
Selenium Liver effects 0.05 Natural deposits, mining,
smelting
Source:
USEPA,
Is Your Drinking Water Safe?
U.S. Environmental Protection Agency,
Washington, DC, 1994; USEPA 816-F-09-004, May 2009.
Note:
The nitrate level is set at 10 mg/L, because nitrate levels above 10 mg/L pose an imme-
diate threat to children under 1 year old. Excessive levels of nitrate can react with hemo-
globin in blood to produce an anemic condition known as “blue babies.” Treated water
is sampled and tested for inorganics at least once per year (Nathanson, 1997).
a
Million fibers per liter.
b
Treatment techniques have been set for lead and copper because the occurrence of these chem-
icals in drinking water usually results from corrosion of plumbing materials. All systems that
do not meet the action level at the tap are required to improve corrosion control treatment to
reduce the levels. The action level for lead is 0.015 mg/L; for copper, it is 1.3 mg/L.
Kidney, nervous system
effects
