United States
Environmental Protection
Agency
Office of Water
4601
EPA811-F-95-0021- T
October 1995
National Primary Drinking
Water Regulations
Lead
CHEMICAL/ PHYSICAL PROPERTIES SOLUBILITIES:
CAS NUMBER: 7439-92-1
COLOR/ FORM/ODOR: Bluish-white, silvery,
gray metal, lustrous when freshly cut.
SOIL SORPTION COEFFICIENT: N/A; Low
mobility in most soils, lowest at neutral
pH and high organic matter.
COMMON ORES:
sulfide-Galena; oxide-Lanarkite;
carbonate-Cerrusite; sulfate-Anglesite
BIOCONCENTRATION FACTOR: Log BCFs for
fish, 1.65; shellfish, 3.4
r
acetate-
. arsenate-
carbonate-
chloride-
' chromate-
nitrate-
oxide-
dioxide-
phosphate-
. sulfate-
sulfide-
tetraethyl-
thiocyanate-
thiosulfate-
443 g/L at 20 deg C
insoluble in cold water
0.0011 g/L at 20 deg C
10 g/L cold water
0.2 mg/L
376.5 g/L at 0 deg C
0.05 g/L at 20 deg C
insoluble
insoluble
0.4 g/L
insoluble
0.29 mg/L at 25 deg C
0.5 g/L at 20 deg C
0.3 g/L cold water
DRINKING WATER STANDARDS
HCLG: zero
Ktion Level:
HAL(child):
> 0.015 mg/L in more
than 10 percent of tap
water samples
none -
HEALTH EFFECTS SUMMARY
Acute: Lead can cause a variety of
adverse health effects in humans. At rela-
tively low levels of exposure, these ef-
fects may include interference with red
blood'cell chemistry, delays in normal
physical and mental development in ba-
bies and young children, slight deficits in
the attention span, hearing, and learning
abilities of children, and slight increases
in the blood pressure of some adults. It
appears that some of these effects, par-
ticularly changes in the levels of certain
blood enzymes and in aspects of children's
neurobehavioral development, may oc-
cur at blood lead levels so low as to be
essentially without a threshold.
Chronic: Chronic exposure to lead
has been linked to cerebrovascular and
(flney disease in humans.
Cancer Lead has the potential to cause
cancer from a lifetime exposure at levels
above the action level.
October 1995
USAGE PATTERNS
Lead is the fifth most important metal in
the USA economy in terms of consump-
tion. Of this approximately 85% of the
primary lead is produced domestically.
and 40-50% is recovered and recycled.
Eighty eight percent of the lead mined in
the US comes from seven mines in the
New Lead Belt in southeastern Missouri;
the rest coming from eight mines in Colo-
rado, Idaho, and Utah. Three of the six
USA lead smelters are from this region,
the others are located in Idaho, Montana,
and Texas.
RELEASE PATTERNS
Lead occurs in drinking water from two
sources: (1) Lead in raw water supplies,
i.e., source water or distributed water,
and (2) corrosion of plumbing materials in
the water distribution system (corrosion
by-products)! Most lead contamination is
from corrosion by-products.
Occurrence In Source Water and
Distributed Water. Based on a variety of
water quality surveys, EPA now estimates
that approximately 600 groundwater sys-
tems and about 215 surface suppliers
may have water leaving the treatment
plant with lead levels greater than 0.005
Technical Version
mg/L These two sources together indicate
that less than 1 percent of the public water
systems in the United States have water
entering the distribution system with lead
levels greater than 0.005 mg/L. These
systems serve less than 3 percentof people
that receive their drinking water from pub-
lic water systems.
From 1987 to 1993, according to the
Toxics Release Inventory lead compound
releases to land and water totalled nearly
144 million Ibs., almost all of which was to
land. These releases were primarily from
lead and copper smelting industries. The
largest releases occurred in Missouri, Ari-
zona and Montana. The largest direct
releases to water occurred in Ohio.
Occurrence as a Corrosion By Prod-
uct. Lead in drinking Water results prima-
. rily from corrosion of materials located
Toxics Release Inventory -
Water and Land Releases, 1987-93
Water Land
TOTALS (in pounds) 970,827 143,058,771
Top Twelve States *
MO 4,408 40.656,278
AZ 771 23,240,625
MT 0 20,822,517
UT 4,600 11,881,000
TX . 1,988 11,515,211
OH 127,990 5,196,522
IN 62,894 4,851,940
TN 7,140 2,095,489
IL 26,601 1,930,000
Wl 1.310 1,350,960
MN , 0 - 1,313,895
NM 0 1,060,880
Major Industries*
Lead smelting/refining 31,423 68,996,819
Copper smelting 5,371 34,942,505
Steelworks/blast fum. 379,849 18,149,696
Storage batteries 0 1.867,292
China plumbing fixtures 1,310 1,350,960
Iron foundries 10,021 1,274,777
Copper mining 0 1,240,000
* State/Industry totals only include facilities with
releases greater than 100,000 Ibs.
1^
Printed on Recycled Paper
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throughout the distribution system con-
taining lead and copper and from lead
and copper plumbing materials used to
plumb public- and privately-owned struc-
tures connected to the distribution sys-
tem. The amount of lead in drinking water
attributable to corrosion by-products de-
pends on a number of factors, including
the amount and age of lead and copper
bearing materials susceptible to corro-
sion, how long the water is in contact with
the lead containing surfaces, and how
corrosive the water in the system is to-
ward these material
The potential sources of lead corrosion
by-products found in drinking water can
include: Water service mains (rarely), lead
goosenecks or pigtails, lead service lines
and interior household pipes, lead sol-
ders and fluxes used to connect copper
pipes, alloys containing lead, including
some faucets made of brass or bronze.
Most public water systems serve at
least some buildings with lead solder and/
or lead service lines. EPA estimates that
there are about 10 million lead service
lines/connections. About 20 percent of all
public water systems have some lead
service lines/connections within their dis-
tribution system. .
The amount of lead in drinking vater
depends heavily on the corrosivity of the
water. All water is corrosive to metal
plumbing materials to some degree, even
water termed noncorrosive or water
treated to make it less corrosive. The
corrosivity of water to lead is influenced
by water quality parameters such as pH,
total alkalinity, dissolved inorganic car-
bonate, calcium, and hardness. Galvanic
corrosion of lead into water also occurs
with lead-soldered copper pipes, due to
differences in the electrochemical poten-
tial of the two metals. Grounding of house-
hold electrical systems to plumbing may
also exacerbate galvanic corrosion.
ENVIRONMENTAL FATE
Lead may enter the environment dur-
ing its mining, ore processing, smelting,
refining use, recycling or disposal. The
initial means of entry is via the atmo-
sphere. Lead may also enter the atmo-
sphere from the weathering of soil and
volcanos, but these sources are minor
compared with anthropogenic ones.
Lead will be retained in the upper 2-5
cm of soil, especially soils with at least 5%
organic matter or a pH 5 or above. Leach-
ing is not important under normal condi-
tions. It is expected to slowly undergo
speciation to the more insoluble sulfate,
sulfide, oxide, and phosphate salts.
.Lead enters water from atmospheric
fallout, runoff orwastewater; little is trans-
ferred from natural ores. Metallic lead is
attacked by pure water in the presence of
oxygen, but if the water contains carbon-
ates and silicates, protective films are
formed preventing further attack. That
which dissolves tends to form ligands.
Lead is effectively removed from the wa-
ter column to the sediment by adsorption
to organic matter and clay minerals, pre-
cipitation as insoluble salt, and reaction
with hydrous iron and manganese oxide.
Under most circumstances, adsorption
predominates.
Lake sediment microorganisms are
able to directly rhethylate certain inor-
ganic lead compounds. Under appropri-
ate conditions, dissolution due to anaero-
bic microbial action may be significant in
subsurface environments. The mean per-
centage removal of lead during the acti-
vated sludge process was 82% and was
almost entirely due to the removal of the
insoluble fraction by adsorption onto the
sludge floe and to a much lesser extent,
precipitation.
The most stable form of lead in natural
water is a function of the ions present, the
pH, and the redox potential. In oxidizing .
systems, the least soluble common forms
are probably the carbonate! hydroxide,
and hydroxycarbonate. In reduced sys-
tems where sulfur is present, PbS is the
stable solid. The solubility of Pb is 10 ppb
above pH 8, while near pH 6.5 the solubil-
ity can approach or exceed 100 ppb. Pb(0)
and Pb(+2) can be oxidatively methylated
by naturally occurring compounds such as
methyl iodide and glycine betaine. This
can result in the dissolution of lead already
bound to sediment or particulate matter.
Lead does not appear to bioconcen-
trate significantly in fish but does in some
shellfish such as mussels. Evidence sug-
gests that lead uptake in fish is localized in
the mucous on the epidermis, the dermis,
and scales so that the availability in edible
portions do not pose a human health dan-
ger.
OTHER REGULATORY INFORMATION:
MONITORING:
MoNiroRmo PERIOD
Initial .
After corrosion'
control installation
Reduced monitoring
• Conditional
- Final
ANALYSIS ,
REFERENCE SOURCE .
EPA 800/4-83-043
FOR LEAD
AT HOME TAPS
Every 6 months
Every 6 months
Once a year
Every 3 years
FOR WATER QUALITY PARAMETERS
WITHIN THE AT ENTRY TO THE
DISTRIBUTION DISTRIBUTION
SYSTEM SYSTEM
Every 6 months Every 6 months
Every 6 months Every 2 weeks
Every 6 months
Every 3 years
Every 2 weeks
Every 2 weeks
METHOD NUMBER
239.2. 200.8; 200.9
TREATMENT: BEST AVAILABLE TECHNOLOGIES
Source water. Ion exchange; lime softening; reverse osmosis; coagulation/filtration
Corrosion Control: pH and alkalinity adjustment; calcium adjustment; silica- or phosphate-based
corrosion inhibition .
FOR ADDITIONAL INFORMATION:
4 EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
* Other sources of toxicologies! and environmental fate data include:
•Toxic Substance Control Act Information Line-202/554-1404
• Toxics Release Inventory, National Library of Medicine - 301/496-6531
• Agency for Toxic Substances and Disease Registry - 404/639-6000
October 1995
Technical Version
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