Occurrence in
Drinking Water,
Food, and Air
Science and Technology Branch
Criteria and Standards Division
Office of Drinking Water
United States Environmental Protection Agency
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OCCURRENCE OF LEAD
IN
DRINKING WATER, FOOD, AND AIR
Prepared by:
Frank Letkiewicz
Denis Borum
Corinne Macaluso
Constance Spooner
JRB Associates
8400 Westpark Drive
McLean, Virginia 22102
EPA Contract No. 68-01-6947, Work Assignment 4
JRB Project No. 2-813-07-095-01
EPA Task Manager
Mr. William Coniglio
January 29, 1985
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ACKNOWLEDGEMENTS
The authors of this document express deep appreciation to Mr. William
Coniglio, EPA Office of Drinking Water, Science and Technology Branch, who
developed the basic concepts culminating in this series of reports on the
occurrence of chemicals in drinking water, food, and air.
The authors also express deep appreciation to Edward Glick, Kitty Miller,
Hugh Hanson, and Nancy Wentworth of EPA's Office of Drinking Water for valu-
able input in developing the drinking water occurrence data presented in this
report.
Bruce Brower, Cornell University, is acknowledged for his assistance in
developing the data from the Rural Water Survey.
A special acknowledgement is made to Diane Simmons for her painstaking
efforts in the word processing of all text and tables in this report.
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TABLE OF CONTENTS
Page
SUMMARY i
INTRODUCTION 1
1. SOURCES AND OCCURRENCE OF LEAD IN THE ENVIRONMENT 2
1.1 GEOLOGIC MATERIALS.... 2
1.2 SOILS 5
1.3 WATER 8
1.4 ATMOSPHERE 14
1.5 PLANTS, ANIMALS, AND HUMANS 16
1.6 SUMMARY OF SOURCES OF LEAD IN THE ENVIRONMENT 22
2. OCCURRENCE IN DRINKING WATER 24
2.1 DISTRIBUTION SYSTEM SOURCES OF LEAD TO DRINKING WATER 24
2.2 FEDERAL SURVEY DATA 26
2.2.1 1969 Community Water Supply Study (1969 CWSS) 26
2.2.2 1978 Community Water Supply Survey (1978 CWSS) 28
2.2.3 Rural Water Survey 31
2.2.4 Compliance Monitoring Data 34
2.3 SUMMARY OF DRINKING WATER OCCURRENCE OF LEAD 39
3. OCCURRENCE IN FOOD 41
4. OCCURRENCE IN AMBIENT AIR 49
5. HUMAN EXPOSURE FROM DRINKING WATER, FOOD, AIR, AND DUST 54
5.1 DRINKING WATER INTAKE 54
5.2 FOOD INTAKE 55
5.3 RESPIRATORY INTAKE 58
5.4 INTAKE FROM DUST 59
6. RELATIVE SOURCE CONTRIBUTION 60
REFERENCES 62
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SUMMARY
Lead, a relatively rare earth metal, occurs in the earth's crust at an
average concentration of 15 ppm. Lead is ubiquitous in the environment and
its occurrence in different media is influenced by natural and anthropogenic
sources. The major source of lead resulting in human exposure is the combus-
tion of leaded gasoline, with minor amounts contributed from industrial
sources. Atmospheric lead is a major contributor to the lead levels found in
soil and dust and can influence lead levels in food both by direct deposition
and uptake from soil.
Deposition of atmospheric lead in surface water and groundwater is less
important environmentally because most of the lead is insoluble and is
deposited in sediments. Lead in surface water and groundwater generally
results from contact of the water with lead-containing geologic materials.
Surface waters normally do not have lead levels above 13 ug/1, although some
locations have reported lead levels as high as 10,350 ug/1. Groundwaters also
have a wide range of reported values (up to 1,600 ug/1), with typical values
(17.7 ug/1) slightly higher than those found in surface water.
In the United States, about 541,000 metric tons of lead are produced and
about 1,350,000 metric tons are consumed. Half of the total consumption is
derived from recycled scrap. The majority of lead demand in the United States
is for the manufacture of storage batteries, and for tetraethyl and tetra-
methyl lead used as antiknock additives in gasoline (this latter use is
declining). Minor uses include the manufacture of pigments, ammunition,
solders, plumbing, cable covering, bearings, and caulking.
It is difficult to derive a clear picture of lead occurrence in public
water supplies based on the information collected. It appears that the prin-
cipal source of lead in drinking water as consumed by individuals using public
drinking water supplies is the distribution system. The information reviewed
indicates that the level of lead in drinking water is higher in samples taken
where there is newly installed plumbing in the distribution system using lead
pipe or lead solder, together with corrosive water (i.e., low pH, alkalinity,
and hardness). It is also evident that lead levels due to the distribution
system are higher in drinking water samples taken after prolonged contact with
the plumbing, such as overnight standing. Under circumstances favoring lead
i
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entering drinking water from the distribution system, it does not appear
unusual to observe lead levels above the current MCL, particularly in first
flush samples.
The available compliance monitoring data indicate that 59 groundwater and
7 surface water supplies in the United States are delivering lead with levels
above the current MCL of 50 ug/1. It is not known whether the observed MCL
violations are due to high lead levels in the source water or to lead added
from the distribution system.
The three national surveys provide limited insight to the national occur-
rence of lead in public water supplies. The 1969 CWSS, which is the oldest
data set, suggests that lead occurs in most public water supplies (90-95%),
with both mean and median concentrations of approximately 12 ug/1 for both
groundwater and surface water. Only one supply in the 1969 CWSS was reported
to have lead above the current MCL. The more recent Rural Water Survey also
indicates a high frequency of occurrence of lead (70-75%); however, the RWS
suggests that the mean of the positive values is considerably higher than that
observed in the 1969 CWSS, ranging from 34-43 ug/1. (Median values were 18-20
ug/1 in the RWS.) Also, the RWS suggested that 15-20% of supplies had values
exceeding the current MCL. As noted, however, the analytical reliability of
the RWS lead data have been questioned. The considerably smaller 1978 CWSS
data set provide results more comparable to the 1969 CWSS for surface water
(10.7 ug/1 mean value, none above the MCL) and more comparable to the RWS for
groundwater (30.3 ug/1 mean value, 9% above the MCL).
None of the national surveys provided sufficient details about the actual
samples collected (characteristics of the distribution system; water corrosiv-
ity, etc.) to allow for a full assessment of the reported results. While it
seems clear that lead is a frequent contaminant of drinking water received by
consumers using public water supplies, the factors affecting lead concen-
trations are too varied to arrive at a determination of typical levels of
occurrence.
Lead is found in most of the food composites examined as part of the FDA
Total Diet Study (Market Basket Survey), though generally at concentrations
less than 0.05 ppm. The major contributors to dietary intake are the legume
vegetables and garden fruits categories, where levels of 0.13-0.18 ppm and
0.10-0.14 ppm are reported, respectively. The estimated daily dietary intake
ii
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of lead for adults is 35.8 ug; assuming 15% absorption, the absorbed dose from
the diet for the 70-kg adult male is 0.077 ug/kg/day.
Atmospheric lead levels have been measured in a number of studies. EPA
has indicated that typical atmospheric lead levels are 0.2 ug/m^ for rural
areas, and 0.8 ug/m^ for urban areas. Adjusting for the indoor/outdoor ratio
of lead in air, EPA has estimated the intake for the adult male to be 1.0
ug/day. Assuming 50% absorption, this intake results in an absorbed dose of
0.007 ug/kg/day for the 70-kg adult male.
Levels of lead in dust have also been measured by EPA (USEPA 1983).
Their current estimate of human exposure includes 300 ug/g of dust lead from
household dusts, 90 ug/g from street dust, and 150 ug/g from occupational
dust. EPA also estimates that an adult ingests 0.01 g/day of household dusts
and 0.01 g/day of occupational dust, with no significant ingestion from street
dust. Therefore, given what would be a total of 4.5 ug/day of dust lead
consumed, and assuming an absorption rate of 15%, this intake results in an
absorbed dose of 0.0096 ug/kg/day for the 70-kg adult male.
It is not possible to develop a detailed profile of human exposure to
lead or of the relative contributions from drinking water, air, and food. It
appears, however, that inhaled air is a relatively minor source for the
majority of adults, and that food is the predominant source when drinking
water levels are below approximately 20-25 ug/1. At higher levels, however,
drinking water predominates; at the current MCL of 50 ug/1, drinking water
would be responsible for about 70% of the absorbed dose for an adult male.
For newborn formula-fed infants, drinking water is the predominant source
at approximately 30 ug/1; however, the absorbed dose experienced by infants is
more than ten times greater on a body weight basis than that received by
adults exposed to drinking water at a given concentration of lead.
iii
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INTRODUCTION
This report addresses the occurrence of lead in drinking water, food, and
air. It has been prepared by EPA's Office of Drinking Water in connection
with the assessment of existing National Interim Primary Drinking Water
Regulations.
The National Interim Primary MCL for lead (0.05 mg/1) was promulgated in
December 1975 (40 FR 59566) under the authority of the Safe Drinking Water Act
and became effective in June 1977. The lead MCL applies to the approximately
60,000 community water supplies currently serving an estimated 214 million
people in the United States. The current MCL for lead was derived from the
1962 U.S. Public Health Services Standard (27 FR 2152).
The evaluation of the occurrence of lead in drinking water, food, and air
presented in this report is intended to support EPA's assessment of this
substance in two principal areas. As input to the health risk assessment of
lead, this report provides an estimate of human exposure to various levels of
lead in drinking water from public water supplies. Information on dietary
intake, respiratory intake from ambient air, and intake from dust is also
provided for perspective and is used to evaluate the relative contributions of
those sources, particularly of drinking water, to the total dose received by
individuals. While it is recognized that some individuals may be exposed to
lead from other sources, such as occupational settings or the use of parti-
cular consumer products, this analysis is limited to drinking water, food, and
air because they are the exposure routes common to all individuals.
In addition to serving as input to the health assessment, this report is
also intended to support EPA efforts to estimate the economic impact of the
regulatory and treatment alternatives being considered. To aid in that
effort, data are provided in this report of the observed distribution of lead
levels in public water supplies of various water source and system size
categories.
This report is not intended to be an exhaustive, comprehensive review of
all existing data on the occurrence of lead and human exposure to it. It
does, however, present the most current and representative information avail-
able for understanding the occurrence of lead in drinking water, food, and
air, and for assessing the importance of drinking water as a route of human
exposure.
1
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1. SOURCES AND OCCURRENCE OF LEAD IN THE ENVIRONMENT
Lead (Pb) is a member of Group IVA of the periodic table and has an
atomic number of 82 and atomic weight of 207.2. It forms compounds corre-
sponding to oxidation states of +2 and +4, with +2 being the most common
(Kirk-Othmer 1981). Lead is a bluish-gray metal with four naturally occurring
isotopes. Three artificial radioactive isotopes of lead have been reported
(Windholz et al. 1976). Lead exhibits excellent corrosion resistance to air,
water, and soil, forming protective coatings of insoluble lead compounds after
reaction with these environmental media (Kirk-Othmer 1981).
The United States produced about 541,000 metric tons of lead and consumed
about 1,350,000 metric tons in 1978 (Kirk-Othmer 1981). Consumption has
remained fairly stable in recent years, with 50% of the total derived from
recycled scrap (Kirk-Othmer 1981, USEPA 1980).
More than half of the lead consumed in the United States is used in the
manufacture of storage batteries. Another major use of lead is for tetraethyl
lead and tetramethyl lead used as antiknock additives in gasoline, although
this use is declining. Other uses include manufacture of pigments, ammuni-
tion, solders, plumbing, cable covering, bearings, and caulking (Kirk-Othmer
1981, USEPA 1980).
Lead is ubiquitous in the environment and its presence in various
environmental compartments can be influenced by both natural processes and
human activities. The remainder of this chapter presents an overview of the
occurrence of lead in the environment and its sources. Chapter 2-6 provide a
more focused review of lead occurrence in drinking water, food, and air, and
the resulting human exposure.
1.1 GEOLOGIC MATERIALS
Lead is a relatively rare metal in the earth's crust. It ranks 34th
among the elements in crustal abundance, with an average concentration of 15
ppm (Morris et al. 1973). Unlike many other metals, the lead content of
igneous and metamorphic rocks increases as the silica content of the rock
increases and the iron and magnesium content diminishes (Lovering 1976).
Thus, lead is more concentrated in granite (a rock that is high in silica)
than it is in basalt (a rock primarily composed of iron and magnesium
minerals). The lead concentrations of a number of rocks are shown in Table 1.
2
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Table 1. Lead Concentrations in Selected Geologic Materials
Lead concentration, ppm
Material
Median
Normal range
Reference
Crustal abundance
15
0.01-100
Lovering 1976, Mason
and Moore 1982
Igneous rocks
13
—
Mason and Moore 1982
Basalt
4
<1-25
Lovering 1976
Gabbro
4
<1-25
Lovering 1976
Gabbroa
<1-260
Mason and Moore 1982
Rhyolite
18
10-100
Lovering 1976
Granite
18
10-100
Lovering 1976
Metamorphic rocks
Granodiorite gneiss3
—
3.3-20
Mason and Moore 1982
Gneiss
12
<1-40
Lovering 1976
Schi st
15
<1-50
Lovering 1976
Amphibolite
10
<1-25
Lovering 1976
Sedimentary rocks
Sandstones
15, 7
10-30
Lovering 1976, Mason
and Moore 1982
Limestones, dolomites
9, 5
3-15
Mason and Moore 1982,
Lovering 1976
Siltstones, shales
15
3-50
Lovering 1976
Carbonaceous shale
20
5-70
Lovering 1976
Deep sea clays
80
Morris et al. 1973
Soils
2-500
0.1-2,000
Mason and Moore 1982
Marine sediments
60
—
Lovering 1976
Terrestrial sediments
15
—
Lovering 1976
Soils, Western states
18
—
Shacklette et al.
1971
Soils, Eastern states
14
Shacklette et al.
1971
Soils near mining activity
50-150
Shacklette et al.
1971
3
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Table 1. Lead Concentrations in Selected Geologic Materials
(continued)
Lead concentration, ppm
Material
Median
Normal range
Reference
Phosphates from Phosphoria
Formation
>100
Lovering 1976
Coal
9
4-218
OTA 1979, Heit 1977
Petroleum
<1
Lovering 1976
Lead ore deposits
30,000-60,000
Kirk-Othmer 1981
Brine from Salton Sea
geothermal field
102
Mason and Moore 1982
aSamples taken from one location.
4
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Lead also appears to be somewhat enriched in geologic materials that
contain organic carbon. The lead content of carbonaceous shale, for example,
is somewhat higher than for the non-carbonaceous shale (Lovering 1976). In
coal, a material rich in organic carbon, lead concentrations can be as high as
218 ppm; however, the average is relatively low at 9 ppm (Heit 1977, OTA
1979).
Lead is the major constituent in over 200 minerals; however, only a few
are of economic importance (Morris et al. 1973). The most Important lead ore
mineral is galena (PbS), followed by anglesite (PbS04) and cerussite
(PbC03). Galena occurs 1n fissure veins and replacement ore bodies. Angle-
site and cerussite are formed by the weathering of galena (Kirk-Othmer
1981). Other Important lead minerals Include mlmetlte [Pb5Cl(AsO^L pyro-
morphlte [PbgCl (PO^], bournonlte [(PbCuSb)S3], crocolte (PbCr04), wulfenite
(PbMo04), and vanadlnlte [PbgCl(V04)3] (K1rk-0thmer 1981, Kraus et al. 1959).
Lead 1s recovered from lead, lead-zinc, copper-lead-zinc, and lead-silver
ores 1n the United States. The chief lead deposits 1n the United States are
shown 1n Figure 1 (Lovering 1976). The largest lead-producing area in the
country 1s 1n southeastern Missouri. The state of Missouri accounts for 90%
of total domestic lead mine output, followed by Idaho, Colorado, Virginia, New
York, Montana, and Arizona (Rathjen 1980). Most lead deposits in the United
States contain more zinc than lead. Exceptions are the southeast Missouri
district, most of the major Utah districts, and the Coeur d'Alene district of
Idaho, where lead 1s more abundant than zinc (Lovering 1976). The concentra-
tion of lead 1n mined deposits generally ranges from 3-6%, although new ore-
dressing techniques are resulting in the use of deposits with lower lead
concentrations (K1rk-0thmer 1981).
Concentrations of lead are uniformly low 1n most geologic materials,
exceptions being lead, zinc, and silver ores, polymetalHc copper ores, and
possibly black shales. Figure 2 shows the general distribution of lead con-
centrations 1n geologic materials 1n the United States.
1.2 SOILS
The concentration of lead In soil and surflclal materials is determined
by the lead content of the parent rock, mining activity, atmospheric deposi-
tion, and the effects of chemical and biological factors. Shacklette et al.
5
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PACIFIC
MOUNTAIN
SYSTEM
1. StmthcuM Miuouri
2. l)p|*t Miuiuip|ii Valley (Witcumin, tlliuois,
luva)
5. (iuruf d'Akur, Idtho
4. AuuiiivillrJv^iliur, Va.
5 liliMiii EdwMiH, N Y.
6. Ilk* UMuivr udfidr drpntiis ol lite Pidmoni
ickmmi, Virginia.
7- llliwM lCrniiKky duiiiii
A. Tn-Suif ditiriii, Miuuuri, OkLduma, and
ILutyt
9. Leadville, Red Qifl. Aqien, and other duuitu.
Colorado mineral brli
10 San Juan Mwmiiim wgkw, Colorado
11. Nuru»uort, Drrp Cwt, and Mruline diMtku,
MxtbeaM WmiiiiMii
12. Bmkcf, Nrihatl, Bultr, Bryaiu. and Oduiado
(foiiiii, wntna Muumih
If. Xh|il ihiia diiifkl, New Mexico
If Central, llauiwer, and iH^rbr ditUitis, New
Mexico
500 KILOMETRES
15. Biatwe diuikt, Aruona
16. tlanfcaw and neaibv districts, Arijuoa
17. ManuBwh and naAy districts. Aruuna
18. Yellow Pint, Nevada, anil mwliy Resting
Spiiugs and Kingston lUnp disiritu, Call*
19. Darwin and nrarby dinrkif iu lnyu Cuumy.
C^tlif.
20. Fiotfar and nearby disimu, Nevada
21. While Pine and fcurrfca distrk it, Nevada
BLUE RIDGE,
PIEOMONT. ANO
„ \NEW ENGLAND
v^3 PROVINCES
EXPLANATION
Boundary of physiographic
provinces
Principal lead districts -
Numbers refer to list of
districts in text page
CitN Mining district or group
of districts ol large area
x'® Mining district or closely
spaced group of districts
'££. San f'raiMiMu
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. o
\
\
Hawaii \^>
* p I
i \
\
L. \
Legend
~ Background concentrations
fljjjl Slightly elevated concentrations
PF1 Elevated concentrations
Figure 2. Lead in Geologic Materials in the United States
Sources: Lovering 19/b, Wedow lb/3, Hidye Ibott, /im and Shatter 19b/,
Slearn, et al. 1979, and Muehlberg, et al. 1977.
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(19711 collected and analyzed samples of soils and other surficial materials
taken throughout the covinous United States. The samples were collected
at a depth of 8 inches fro™ 863 sample sites approximately 50 miles apart.
Samples were taken in such a »ay as to minimize modification b, lead fall-
out The map and histogram in Figure 3 show the results of the survey. The
of lead for all samples was 16 ppm, with a mean
geometric mean concentration ot ibsq
of 18 ppm for the western states and 14 ppm for the eastern states.
Soil lead content was found to be highest in the southeast Missouri lead
belt because of naturally occurring lead deposits and/or mining operations.
Samples taken on the floodplain of a river flowing through the mining district
contained lead at 700-7,000 PP-. I» «« le" » •"»"«
activity, lead levels ranged from 50-150 ppm (Lovertn, 1976).
I„ addition to mining operations, fallout from industrial plants and
automotive exhaust result In high soil lead levels. Soil samples taken within
1 mile of a lead smelter 1n El Paso, Texas, had lead levels averaging 36,853
ug/g in samples taken more than 4 miles from the smelter, the levels
9/9' , at al 1979). The contamination of soil from
- — -«- - -
lead sme oatterns, climatic conditions, and local
cmplter has been in operation, wind patterns,
! h rixFPA 1983) In a study of the lead content in soil near high-
topography (USE ^ ^ had lead 1ev,ls 65.75s 1ess than
ways, samples fron the road (NAs 1972). Soils within 25 meters
samples taken on y t pher1c lead from 30 to 2,000 ug/g above natural
of highways may contain atmosp
levels, all in the upper soil layer
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lead, in parts per million
Geometric mean 16
Geometric deviation 1 96
Number of samples and analyses 863
Figure 3. Lead content of surficial materials.
Source: Shacklette et al. 1971
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Table 2. Normal Lead Content of Uncontaminated Waters
Water type
Median (ug/1)
Normal range (ug/1)
Rivers
8
0.1-100
Lakes
2
0
•
~—1
1
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Table 3. Ranges of Concentrations of Dissolved and Total Lead Levels
at NASQAN Stations During the 1976 Water Year
Range (ug/1)
Region name
Dissolved
Total
New England
0-43
0-140
Mid Atlantic
0-48
0-160
South Atlantic-Gulf
0-66
0-150
Great Lakes
0-150
0-300
Ohio
0-39
0-340
Tennessee
0-16
6-40
Upper Mississippi
0-410
0-320
Lower Mississippi
0-31
0-170
Sour1s-Red-Rainy
0-84
0-100
Missouri Basin
0-41
0-500
Arkansas-Wh1te-Red
0-64
0-400
Texas-Gulf
0-16
0-70
R1o Grande
0-3
0-350
Upper Colorado
0-5
0-800
Lower Colorado
0-45
100-2,900
Great Basin
0-33
0-100
Pacific Northwest
0-47
0-200
California
0-58
0-200
Alaska
0-20
20-100
Hawaii
0-32
0-140
Caribbean
0-18
2-30
Source: Britton et al. 1983
11
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Region numbers and names
01
New England
12
Texas-Gulf
02
Mid Atlantic
13
Rio Grande
03
South Atlantic-Gulf
14
Upper Colorado
04
Great Lakes
15
Lower Colorado
05
Ohio
16
Great Basin
06
Tennessee
17
Pacific Northwest
07
Upper Mississippi
18
California
08
Lower Mississippi
19
Alaska
09
Souris-Red-Rainy
20
Hawaii
10
Missouri Basin
21
Carribbean
11
Arkansas-White-Red
Figure 4. Water Resources Regions of the United States as
designated by the United States Water Resources
Council (Britton et al 1983).
12
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Table
4. Maximum
and Minimum Concentrations of Lead
Found in
Groundwaters
of Some States and
Puerto Rico 1960-
-1971
Percent
Lead
of samples
concentration
Samples J> 50 ug/1
containing
(ug/1)
Number of
mandatory maximum
less than
samples
for drinking water® 10 ug/1
Maximum 1
Minimum
A1abama
2
0
100
ND
ND
Arizona
9
0
56
40
ND
California
7
0
14
46
5.7
Colorado
103
0
96
30
<0.5
Connecticut
1
0
100
<8
<8
Florida
14
0
78
40
ND
Georgia
1
0
100
<2.6
<2.6
Hawaii
3
0
100
5.8
0.6
Illinois
2
0
100
7.5
ND
Indiana
3
0
67h
21
ND
Kansas
3
0
67
4
ND
Kentucky
5
0
100
4
<2
Louisiana
4
0
100
4.5
ND
Missouri
43
0
95
10
<2
Montana
8
0
50
<35
<4
Nebraska
1
0
100
NO
ND
New Jersey
8
0
75
<22
1
New Mexico
13
0
31
30
ND
New York
19
0
89
10
ND
North Carolina
1
0
100
<3
<3
Ohio
26
0
54
30
<3
Pennsylvania
27
0
74
29
<2
Tennessee
5
0
100
3.2
<1.7
Texas
14
0
86
38
ND
Utah
1
1
0
62
—
VIrglnla
1
0
100
<9
<9
Washington
2
0
50
11
<2.6
Wisconsin
1
0
100
7.4
--
Wyomlng
20
1
90
240
/»
<1£
Puerto R1co
6
0
33
Total
353
2
80
—
—
aAs determined by U.S. Public Health Service 1963.
^Includes one value above 10 ug/1.
CA11 values are reported as "less than" because of high dissolved solids.
ND * Not detected
Source: Loverlng 1976
13
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1.4 ATMOSPHERE
Natural concentrations of lead in the atmosphere are estimated to be
between 0.02 and 0.07 ng/m3 (USEPA 1983). Lead levels ranging from 0.1-1.0
ng/nr have been measured in remote areas (USEPA 1980). The natural sources of
lead in air are as follows (Lovering 1976):
Source Lead (ng/m3)
Silicate dust from soils 0.5
Volcanic halogen aerosols 0.03
Volcanic silicate smoke 0.006
Forest fire smoke 0.006
Aerosolic sea salts 0.001
Meteorites and meteoritic smoke 0.000002
In addition to these sources, lead vapor can can be released from vege-
tation. In mineralized areas, this lead release produced air levels of 1-12
ppb, which may be a significant contribution locally (Lovering 1976).
The concentration, of lead 1n the atmosphere has increased over natural
levels because of human activities. One study investigated lead concentra-
tions 1n layers of snow strata In Greenland corresponding to different chrono-
logic periods. Levels of lead in 1ce in 1750 AD (beginning of the Industrial
Revolution) were 20 times those 1n 800 BC. A dramatic rise occurred after
1940 because of the use of lead compounds in gasoline (NAS 1972, NSF 1977).
The major source of lead emissions to the atmosphere is the exhaust from
the combustion of leaded gasoline, accounting for approximately 88% of atmos-
pheric lead. Primary copper and lead smelting facilities contribute 2.5% and
1.7% of atmospheric lead, respectively (Drill et al. 1979). Coking of coal
with a high lead content, combustion of waste oil, and incineration of solid
wastes may produce high lead concentrations locally (Rathjen 1980). Data 1n
Table 5 (Battye 1983) shows lead emissions and their sources for 1981. The
magnitude of other sources of lead releases to the environment, including
weathering and incineration of lead-containing materials and lead recovery
from old lead products, 1s unknown (NAS 1972).
Lead can be removed from the atmosphere by aggregation and precipitation
and 1s deposited 1n soils and water. Combustion of leaded gasoline is chiefly
responsible for high lead levels in urban soil and dust. Lead fallout appears
14
-------
Table 5. Lead Emissions in the United States, 1981a
Emission source
Annual U.S.
emissions
(t/yr)
Percentage of
U.S. total
emissions
Gasoline combustion
35,000
85.9
Waste oil combustion
830
2.0
Solid waste disposal
319
0.8
Coal combustion
950
2.3
011 combustion
226
0.6
Wood combustion
—
--
Gray iron production
295
0.7
Iron and steel production
533
1.3
Secondary lead smelting
631
1.5
Primary copper smelting
30
0.1
Ore crushing and grinding
326
0.8
Primary lead smelting
921
2.3
Other metallurgical
54
0.1
Lead alkyl manufacture
245
0.6
Type metal
85
0.2
Portland cement production
71
0.2
Miscellaneous
233
0.5
Total
40,739a
100%
inventory does not Include emissions from exhausting workroom air, burning of
lead-painted surfaces, welding of lead-painted steel structures, or weather-
ing of painted surfaces.
Source: Battye 1983 (as cited in USEPA 1983)
15
-------
to be in an insoluble form in surface waters and is removed by natural sedi-
mentation and filtration (NAS 1972, 1974).
1.5 PLANTS, ANIMALS, AND HUMANS
The concentration of lead in vegetation is highly dependent on the
species of plant, climatic conditions, section of the plant examined, soil
composition, and extent of contamination of the surrounding air and water.
Plants in uncontaminated and unmlnerallzed areas were reported to average 2
ppm of lead (dry weight) (Lovering 1976). Table 6 gives background concentra-
tions of lead in plants. Bowen (1966) reported the following concentrations
of lead in some other dry plant tissues:
Tissue Lead (ppm, dry weight)
Plankton 5
Brown algae 8.4
Bryophytes 3.3
Ferns 2.3
(tymnosperms 1.8
Anglosperms 2.7
Fungi 50
Lead concentrations in garden fruits and vegetable samples were reported
for samples collected in 1961-1963. Results are shown in Table 7.
Greenhouse studies with filtered air (lead at 0.09 ug/m^) showed lead
concentrations ranging from 0.16 ug/g (dry weight) in wheat to 5.8 ug/g in
unharvested leaves of cabbage. Samples taken 520 feet from highways showed
lead levels of 0.10 ug/g (dry weight) 1n soybeans to 12.8 ug/g in chaff from
oats (NAS 1972). These data are 1n general agreement with those in Table 7.
Plants grown in soils developed from rocks with high lead content contain
lead at up to 350 ppm (Lovering 1976). However, there are few totally undis-
turbed mineralized areas and they are, for the most part, uncultivated.
Industrial and agricultural activities can affect lead concentrations in
vegetation. The highest lead level reported in plants near these sources was
664 ppm (Lovering 1976). Mining, milling, and smelting operations can result
in greater absorption of lead through plant roots. Levels of lead in plants
were reported to depend on the distance from refineries (Lovering 1976).
16
-------
Table 6. Normal Lead Concentrations in Various Classes of Vegetation
Locality
Number
of
samples
Type of plant
Part of
plant
Dry weight
Median Range
(ppm) (ppm)
Reference
Western United States
20
Conifer tree
Tips
1.8
1-10
Cannon 1976
(wilderness areas)
193
Deciduous tree
Tips
2.5
0.27-13.0
Chaffee and Cannon
1976
168
Deciduous tree
Stems
1.0
0.16-4.0
Chaffee and Cannon
1976
178
Deciduous tree
Leaves
1.7
<0.61-9.1
Chaffee and Cannon
1976
131
Shrubs
Leaves
4.9
0.57-8.2
Chaffee and Cannon
1976
56
Shrubs
Tips
1.8
0.57-4.3
Chaffee and Cannon
1976
110
Shrubs
Stems
2.1
0.57-8.2
Chaffee and Cannon
1976
15
Grasses
Stems
1.6
<0.8-5.6
Cannon 1976
Western United States
226
Grasses
Above ground
—
—
Miesch 1970
Colorado
10
Lichens
Above ground
81
12.3-150.0
LeRoy and Koksoy 1962
Canada
17
Conifer tree
2d-year
a —
Warren and Delavault 1960
twigs
Source: Lovering 1976; references as cited in source.
-------
Table 7. Lead in Garden Produce
Type of produce
Number of
samples
Lead (ppm,
Median
dry weight)
Range
New York, Maryland,
and New Mexico
Fruits
Apples
8
0.2
<0.2 -0.59
Peaches
2
0.3
<0.4 -0.53
Pears
_2
0.5
—
Total fruit
12
0.25
<0.2 -0.59
Nonleafy vegetables
Asparagus
3
<1
<0.9 - 3.75
Beans (green)
5
0.63
<0.58- 8.4
Beans (shelled)
4
0.93
<0.65- 2.2
Beets
7
<1.8
<1 -12.5
Carrots
8
<1.5
<0.99- 9
Corn
15
<0.25
<0.2 - 1.05
Cucumbers
4
<2
—
Green peppers
7
<1.3
<0.9 - 2.1
0n1ons
5
1.3
0.7 - 1.84
Potatoes
9
<0.48
<0.44- 1.65
Rhubarb
4
1
—
Salsify
2
1.4
<1.2 - 1.7
Squash
8
<1.4
—
Tomatoes
10
1
<0.96- 6.8
Turnips
2
<2.7
—
Leafy vegetables
Cabbage
9
2.3
<1.8 - 4.2
Beet tops
3
8
4.2 -12.5
Kale
4
<2.5
<1.9 - 2.4
Lettuce
6
3.3
<2 -14
Total vegetables
116
<1.3
<0.2 -14
18
-------
Table 7. Lead in Garden Produce
(continued)
Type of produce
Lead (ppm,
Number of
samples Median
dry weight)
Range
Wisconsin,
Iowa, and Minnesota3
Fruit
Apple
3
0.5
<0.5 - 1.0
Vegetables
Asparagus
5
12.0
O
CO
1
CO
•
CM
Bean, pinto (seed)
1
<1.5
—
Been, green (pod)
3
<1.5
--
Beet (root)
4
2.6
<1.4 - 3.6
Cabbage
11
2.2
<1.4 - 3.5
Carrot
8
<2.4
<2.2 - 3.8
Cauliflower
2
<2.0
<2.0 - 2.1
Corn (field)
25
0.4
<0.3 - 2.2
Corn (sweet)
"4
0.5
<0.5 - 1.0
Cucumber
4
2.9
<2.4 -18.7
Onion
7
<1.2
<1.1 - 1.1
Parsnip
1
<1.2
—
Pepper (sweet)
4
<1.7
—
Potato (white)
10
1.2
<0.95- 2.1
Pumpkin
1
<3.0
—
Radish (white)
1
<4.1
—
Rhubarb
1
<4.0
—
Rutabaga
<2.3
—
Squash, hubbard
1
1.2
—
Swiss chard
1
4.8
—
Turnip
1
5.9
—
Total
100
1.3
<0.3 -30
aShacklette 1970
Source: Lovering 1976
19
-------
Agricultural sprays, such as insecticides and fungicides, can contain
lead compounds. Sprayed orchard trees had lead levels up to 100 times higher
than those 1n unsprayed trees (Lovering 1976).
A 1969 study to determine the effects of urban air pollution on plants
showed that washed grass samples collected 5 feet from a highway had lead
concentrations of 222 ppm (dry weight), whereas those collected at a distance
of 1,000 feet had 28 ppm (Lovering 1976). Much of the lead on plants is on
the surface and can be washed off (except from lettuce), but it is unclear
whether absorbed lead is taken up from the soil or in through the leaves (NAS
1972, NSF 1977, Lovering 1976). It also appears that proximity to roads
affects the lead content of vegetation more extensively than does soil lead
content (Lovering 1976). These data are shown in Table 8.
Table 8. Comparison of Lead Content Between On-Road and Off-Road
Samples of Some Soils and Plants in Missouri
Locality
Sample type
Number of
samples
Lead content (ppm)a
On-road*5 0ff-roadc
Various
Cedar branch tips
32
16
7
Soil
32
17
14
Kansas City, M0
Grass
30
29.0
9.7
Soil
30
10
14
Pacific, M0
Grass
30
17.0
4.5
Soil
30
10.0
3.5
aDry weight, geometric mean
^Samples taken <50 feet (15 m) from road
cSamples taken >500 feet (152 m) from road
Source: Lovering 1976
Lead concentrations 1n dry animal tissues as reported by Bowen (1966) are
as follows:
20
-------
Tissue Lead (ppm)
Coelenterates 35
Molluscs 0.7
Crustaceans 0.3
Insects _< 7
Fish 0.5
Mammals 4
Echinoderms 18
Of the lead that is absorbed in the human adult, approximately 95% of total
body lead accumulates in the skeleton (i.e., bones and teeth). Levels may
potentially be as high as 200 mg 1n men aged 60-70 years (USEPA 1983). About
73% of total body lead 1n children accumulates 1n the skeleton (USEPA 1983).
Table 9 gives lead concentrations found 1n tissues of persons not occupa-
tional ly exposed to lead.
Table 9. Lead Concentrations 1n Various Tissues
of Children and Male Adults (ppm, Met weight)
Tissue
Male adult
Children (2-9 years)
Tibia
23.4
3.70
R1b
8.85
3.01
Liver
1.03
0.87
K1dney
Cortex
0.78
0.70
Medulla
0.50
0.49
Prostate
0.27
0.48
Spleen
0.23
0.13
Lung
0.22
0.19
Skin
0.19
0.63
Thyroid
0.19
0.28
Brain cortex
0.10
0.09
Stomach
0.09
0.11
Heart
0.07
0.09
Source: Drill et al. 1979
21
-------
1.6 SUMMARY OF SOURCES OF LEAD IN THE ENVIRONMENT
The preceding sections of this chapter addressed the occurrence of lead
in the environment and its natural and anthropogenic sources. Figure 5, from
the USEPA (1983) report, provides a general, if somewhat simplified, depiction
of the major processes involved 1n the transfer of lead from the environment
to man.
The major source of lead in the environment is the combustion of leaded
gasoline, with minor amounts contributed from industrial sources. This atmo-
spheric lead is a major contributor to the high lead levels found in urban
soil and dust. Deposition of atmospheric lead 1n surface and groundwaters is
less Important environmentally, because most of the lead is insoluble and is
deposited fn sediments.
Lead 1s a natural constituent of the earth's crust but, as discussed
above, It appears that much of the lead present 1n the environment 1s a result
of human activities. Lead occurs naturally 1n rocks and soils and is present
1n low levels naturally 1n the atmosphere. Natural concentrations of lead in
surface and groundwaters are low because of the chemical properties of the
more common forms of lead.
Some plant species can take up high concentrations of lead from soils
derived from mineral deposits. Plants can also be contaminated by lead from
auto exhaust fumes, industrial smoke, and lead-containing insecticides.
Humans and animals can absorb lead from food, air, and water. Ingestion of
soil, dust, and other lead-containing materials can be major sources of expo-
sure for children. Lead tends to concentrate 1n the bone 1n humans and other
mammals.
22
-------
Figure 5. Pathway*
From the
Sourcet
for the Transfer of Lead
Environment to Man.
USEPA 1983.
23
-------
2. OCCURRENCE IN DRINKING HATER
The purpose of this chapter is to present information useful for gaining
a national view of lead occurrence in public drinking water supplies. The
information available on the occurrence of lead in drinking water in the
United States Includes the results of three Federal surveys, compliance
monitoring data developed 1n response to the National Interim Primary Drinking
Water Regulations, studies conducted by state agencies, and miscellaneous
published and unpublished data. Due to resource constraints limiting the
feasibility of collecting and assessing all available data on lead levels in
drinking water, 1t was determined that the national view would be developed
from the Federal survey data (presented in Section 2.2) and the compliance
monitoring data (presented 1n Section 2.3). Section 2.1 presents a discussion
of the entry of lead Into drinking water from the distribution system.
2.1 DISTRIBUTION SYSTEM SOURCES OF LEAD TO DRINKING MATER
The Information presented 1n Chapter 1 suggests that lead in drinking
water may result from a natural occurrence 1n the source water and as a con-
taminant resulting from Industrial and agricultural activities. An additional
potential source of lead in drinking water as delivered at the consumer's tap
1s from the corrosion of pipes in the distribution system.
According to NAS (1977), the available data suggest that the addition of
lead to drinking water occurs chiefly in the distribution system. Water
distribution systems using lead pipes or lead alloy solder to join copper
pipes constitute an important source of lead contamination for drinking water,
especially 1n areas having soft water with an acid pH. Also, lead concentra-
tions are usually higher 1n samples taken after water has been standing in the
pipes for several hours (first flush) than after the tap has been running for
a time prior to sampling. Leaching of lead from plastic pipes has also been
reported.
The relationship between lead contamination of drinking water and distri-
bution system characteristics has been the subject of several studies.
The age of the pipes in the distribution system appears to have an impact
on how much lead the population consumes in drinking water. According to a
study of trace metal exposure in Seattle, Washington, lead concentrations in
24
-------
water from homes with copper pipes were associated with the age of the house.
Median concentrations of lead in standing water were 31 ug/1 among houses less
than 5 years of age, and were 4.4 ug/1 among older houses (P < 0.001). Seven
houses constructed within the last 18 months had even higher concentrations,
with a median of 67 ug/1. Beyond 5 years, there appeared to be no relation-
ship to age. Among the homes with galvanized pipes, lead levels were also
higher with newer houses. Median concentrations in the newer and older groups
were 4.8 and 3.6 ug/1 for lead, respectively (P < 0.05). The study concluded
that the major source of lead, probably on the Inside of soldered joints, is
substantially lost or coated over within a few years (Sharrett et al. 1982).
Several studies were reported 1n Lassovszky (1984) on the leaching of
lead from soldered joints of copper pipe plumbing. Lassovszky also indicated
that such leaching occurs primarily 1n newly installed plumbing conveying
corrosive waters (I.e., low 1n pH, alkalinity, and hardness). The presence of
chlorides and sulfates may also Increase corroslvlty. The leaching of lead
from soldered joints may also occur due to galvanic corrosion, that 1s, elec-
trolytic corrosion of the solder, and lead levels 1n general tend to Increase
with Increased contact time of the water with the plumbing (Lassovszky
1984). Rossum (1975, as cited In Lassovszky 1984), in an unpublished study,
monitored metals 1n drinking water from contact with materials used in resi-
dential plumbing. Again, the presence of lead was attributed to the age of
the plumbing, as well as to water quality factors. Water samples were col-
lected from distribution systems after 8 hours of stagnation time followed by
flushing of approximately 10 gallons of water. Lead levels 1n the first drawn
samples from houses with new copper plumbing (less than 1 year old) were
likely to exceed the MCL. However, after flushing the system, lead levels did
not exceed the MCL of 50 ug/1 1n any of the samples.
An additional long-term study by Rossum (1975, as cited 1n Lassovszky
1984) involving a simulated plumbing system showed that non-corrosive water
(with a pH of 7.4, 230 mg/1 alkalinity, and 270 mg/1 hardness) passed through
the system resulted 1n lead levels of 400 ug/1 1n the first drawn samples of
short-term exposure rates (I.e., 12 to 24 hours). However, after 30 days of
use, the levels of lead .1n the first drawn sample were below the MCL. When
corrosive water (with a pH of 7.4, 8 mg/1 alkalinity, and 20 mg/1 hardness)
was passed through the system, first drawn samples similarly contained 400
25
-------
ug/1 of lead. Although the levels of lead (with corrosive water) in the first
drawn samples decreased with the age of the system, they did not decrease
below the MCL until after 340 days of use. Rossum nevertheless concluded that
the age of the plumbing was the greatest factor on the leaching of lead into
the water from soldered copper pipe joints.
Lovell et al. (1978, as cited in Lassovszky 1984) conducted a random
sampling of household drinking water in Carroll County, Maryland. The plumb-
ing at the sites consisted of copper tubing joined with lead solder. Of 350
wells surveyed, 78 of the first drawn samples, after overnight exposure to the
plumbing system, contained lead levels above the MCL. About 73% of these
samples were from distribution systems that were five years old or less. The
authors also observed higher concentrations in the water samples having lower
pH levels.
Murrel et al. (1982, as cited in Lassovszky 1984) conducted sampling at
various locations on Long Island, New York, because of complaints about exces-
sive levels of lead in drinking waters. Results showed that in newly con-
structed plumbing systems, the first drawn samples contained lead levels in
excess of the MCL, with levels as high as 7,100 ug/1. After flushing of the
systems, lead levels 1n the water decreased below the MCL.
Plastic pipes may also be a source of lead contamination in drinking
water. In laboratory tests (Farish 1969) of lead-stabilized PCV plastic pipe
produced 1n the United States and abroad, lead concentrations in water ranged
from 0.3-2.0 mg/1 (NRC 1977).
2.2 FEDERAL SURVEY DATA
Three national surveys provide data on lead in public drinking water
supplies: the 1969 Community Water Supply Study, the 1978 Community Water
Supply Survey, and the Rural Water Survey. The following sections describe
those surveys and present the data from each on lead levels in groundwater and
surface water supplies.
2.2.1 1969 Cowmnlty Mater Supply Study (1969 CWSS)
The U.S. Public Health Service conducted the Community Water Supply Study
(CWSS) 1n 1969 to assess the status of the nation's water supply facilities
26
-------
and drinking water quality (McCabe et al. 1970, USPHS 1970). Finished water
from a total of 969 community supplies were studied in the nine geographically
distributed areas listed in Table 10. Except for the state of Vermont (in
which all supplies were sampled), the study locations are standard metropoli-
tan statistical areas (SMSAs). Water samples were reported to have been taken
at various places in the distribution system of each supply studied after
flushing for several seconds. Of the 969 systems, 678 were groundwater
supplies, 109 were surface water supplies, and the remaining 182 were mixed
sources, purchased water, or of unspecified source. Analytical results for
lead were provided for 673 groundwater supplies and 109 surface water
supplies.
Table 10. Locations Examined in the 1969 Community Water Supply Study
Region
Location
Population
(1n thousands)
Number of water supply
systems studied
I
Vermont (entire state)
307.2
218
II
New York, New York
12,356.3
221
III
Charleston, West Virginia
229.3
30
IV
Charleston, South Carolina
251.1
22
V
Cincinnati, Ohio
1,366.0
66
VI
Kansas City, Missouri-Kansas
1,383.5
88
VII
New Orleans, Louisiana
1,085.4
26
VIII
Pueblo, Colorado
111.5
20
IX
San Bernard1no-R1vers1de-0ntar1o, 1,118.4
California
278
18,203.8
969
The results of the 1969 CWSS were published in several volumes addressing
each of the study areas and the national findings. The published volumes of
the 1969 CWSS did not provide complete data on the water source, population
served, and lead levels measured for each system sampled. However, a computer
27
-------
file with the requisite data was prepared for the 1969 CWSS by JRB using the
published data and additional information provided by Dr. Rolf Deininger of
the University of Michigan and EPA staff.
The published information on the 1969 CWSS does not specify a detection
limit or minimum quantifiable concentration for lead. The "negative" findings
for individual supplies were reported as having a value of 0 ug/1.
Tables 11 and 12 summarize the results of the 1969 CWSS; the results are
displayed as a function of system size based on the population served. The
concentration ranges selected are based on the current MCL for lead (50 ug/1);
each Increment of the range 1s 12.5 ug/1, one-fourth of the current MCL.
Lead was observed in 595 of the 673 groundwater supplies for which data
are available (88.4%). The values of the positives ranged from 0.5-72 ug/1,
with a mean of 12.6 ug/1 (standard deviation, 8.0 ug/1) and a median of 11.0
ug/1. Only one groundwater supply had a level exceeding the MCL. All of the
supplies having high values were smaller systems, serving fewer than 3,300
people (Table 11).
Lead was reported to be present In 104 of the 109 surface water supplies
sampled in the 1969 CWSS (95.4%) at levels ranging from 1.3-32.5 ug/1. The
mean value was 12.9 ug/1 (standard deviation, 6.3 ug/1) and the median value
was 12.3 ug/1 (Table 12).
2.2.2 1978 Co—unity Water Supply Survey (1978 CWSS)
The 1978 Community Water Supply Survey was conducted by the U.S.
Environmental Protection Agency to determine the occurrence of a number of
organic and inorganic compounds In public water supplies dispersed throughout
the Unltd States. Drinking water samples were provided by approximately 500
supplies; however, due to analytical problems, reliable data for lead were
available for only 33 groundwater and 10 surface water supplies (Glick 1984).
The analytical method used for lead was atomic absorption spectro-
photometry (graphite furnace); the minimum quantifiable concentration was 5
ug/1. In the 1978 CWSS, supplies provided one to five samples of raw,
finished (I.e., treated water sampled at the supply), and/or distribution
water (I.e., water sampled at a user's tap). For the purpose of this
28
-------
Table 11. Reported Occurrence of Lead in Groundwater Systems Sampled in 1969 CUSS
«//
System size Number of Number of systems with measured concentrations (ug/1) of:
(population
served)
systems
studied
Negative
systems4
_<12.5
>12.5-25.0
>25.0-37.5
>37.5-50.0
>50.0-62.5
>62.5-75.0
>75.0
25-100
128
20
54
42
8
4
0
0
0
101-500
238
29
118
79
8
3
0
1
0
501-1,000
59
6
28
21
4
0
0
0
0
1,001-2,500
75
12
36
22
5
0
0
0
0
2,501-3,300
14
0
12
1
0
1
0
0
0
3,301-5,000
35
4
22
8
1
0
0
0
0
5,001-10,000
46
2
29
14
1
0
0
0
0
10,001-50,000
62
5
38
16
3
0
0
0
0
50,001-75,000
4
0
3
1
0
0
0
0
0
75,001-100,000
3
0
2
1
0
0
0
0
0
>100,000
9
_0
7
2
_0
_0
0
J)
J)
Total
673
78
349
207
30
8
0
1
0
aReported as having 0 ug/1 lead.
-------
Table 12. Reported Occurrence of Lead in Surface Water Systems
Sampled in 1969 CUSS
Number of systems with measured
System size Number of concentrations (ug/1) of:
(population
served)
systems
studied
Negative
systems3
112.5
">12.5-
25.0
>25.0-
37.5
>37.5-
50.0
>50.0
25-100
12
1
4
6
1
0
0
101-500
19
1
6
12
0
0
0
501-1,000
14
0
7
6
1
0
0
1,001-2,500
24
2
11
11
0
0
0
2,501-3,300
2
0
2
0
0
0
0
3,301-5,000
8
0
4
3
1
0
0
5,001-10,000
1
0
3
3
1
0
0
10,001-50,000
10
0
8
2
0
0
0
50,001-75,000
3
1
2
0
0
0
0
75,001-100,000
2
0
2
0
0
0
0
>100,000
8
£
_6
_2
J)
0
_0
Total
109
5
55
45
4
0
0
aReported as having 0 ug/1 lead.
30
-------
analysis, the results for finished and distribution samples were averaged*;
raw water data were not used. No information was available on flushing prior
to sample collection.
Table 13 summarizes the results of the 1978 CWSS for lead in groundwater
supplies. Of the 33 supplies sampled, 23 (69.7%) reported lead to be present
at concentrations ranging from 5-182 ug/1. The mean value for positive
samples was 30.3 ug/1 (standard deviation, 40.2 ug/1) and the median value was
22.0 ug/1. Only three groundwater supplies had levels exceeding the MCL. All
of these supplies were small systems, serving fewer than 2,500 people.
Six of the 10 surface water supplies sampled (60%) were reported to have
lead present above the minimum quantifiable concentration of 5 ug/1. Positive
values ranged from 5-20 ug/1. The mean value for positive samples was 10.7
ug/1 (standard deviation, 6.3 ug/1) and the median value was 8.0 ug/1 (Table
14).
2.2.3 Rural Water Survey
The third national survey providing data on lead levels 1n U.S. drinking
water supplies 1s the Rural Water Survey (RWS) (Brower 1983) conducted between
1978 and 1980 to evaluate the status of drinking water in rural America as
required by Section 3 of the Safe Drinking Water Act. The RWS examined drink-
ing water from over 2,000 households 1n rural areas for a variety of water
quality parameters. Many of these households used private wells or very small
systems serving fewer than 25 people. A total of 648 public water supplies
(494 groundwater, 154 surface water) provided water to households surveyed in
the RWS for lead levels.
In the RWS, the number of service connections associated with water
systems was reported 1n lieu of the actual populations served by the
systems. Or. Bruce Brower of Cornell University, who collaborated in the
National Statistical Assessment of Rural Water Conditions (based on the RWS
data) provided a factor to convert the data from service connections to the
~This was done on the recommendation of Brass (1983), who Indicated that the
designation of samples as finished or distribution 1n the 1978 CWSS was not
consistent.
31
-------
Table 13. Reported Occurrence of Lead In Groundwater Systems Sampled In 1978 CNSS
Number of systems with measured concentrations (uq/l) of:
System size
(population
served)
Number of
systems
studied
Negative
systems8
2.5.0-
12.5
>12.5-
25.0
>25.0-
37.5
>37.5-
50.0
>50.0-
62.5
>62.5-
75.0
>75.0-
87.5
>87.5-
100.0
>100.0-
112.5
>112.5-
125.0
>125.0-
137.5
>137.5-
150.0
>150.0
25-100
4
1
0
1
1
0
0
0
0
0
0
0
0
0
1
101-500
13
6
3
1
2
0
0
0
0
0
1
0
0
0
0
501-1,000
3
1
0
0
2
0
0
0
0
0
0
0
0
0
0
1.001-2,500
7
2
2
1
1
0
0
1
0
0
0
0
0
0
0
2,501-3,300
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3,301-5,000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5,001-10,000
2
0
1
0
0
1
0
0
0
0
0
0
0
0
0
10,001-50,000
3
0
3
0
0
0
0
0
0
0
0
0
0
0
0
50,001-75,000
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
75,001-100,000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
>100,000
0
0
0
£
£
£
0.
£
£
0_
J)
£
.0
£
£
Total
33
10
10
3
6
1
0
1
0
0
1
0
0
0
1
"Bel cm the minimum quantifiable concentration of 5 ug/i.
-------
Table 14. Reported Occurrence of Lead in Surface Water Systems
Sampled in 1978 CWSS
Number of systems with measured
System size Number of concentrations (ug/1) of:
(population
served)
systems
studied
Negative
systems3
>5.0-'
T2.5
>12.5-
25.0
>25.0-
37.5
>37.5-
50.0
>50.0
25-100
0
0
0
0
0
0
0
101-500
1
1
0
0
0
0
0
501-1,000
1
0
1
0
0
0
0
1,001-2,500
0
0
0
0
0
0
0
2,501-3,300
0
0
0
0
0
0
0
3,301-5,000
2
1
1
0
0
0
0
5,001-10,000
2
2
0
0
0
0
0
10,001-50,000
1
0
1
0
0
0
0
50,001-75,000
3
0
1
2
0
0
0
75,001-100,000
0
0
0
0
0
0
0
>100,000
_0
_0
0
£
_0
_0
Total
10
4
4
2
0
0
0
aBelow the minimum quantifiable concentration of 5 ug/1.
33
-------
number of people served, based on the average number of persons per household
observed in the RWS. It must be noted, however, that the population served
values for supplies sampled in the RWS are only approximations.
Details were not available on the sample collection or analytical method-
ology used. However, the minimum quantifiable concentration appeared to be 5
ug/1. Table 15 summarizes the results of the RWS for lead in groundwater
supplies. Of the 494 supplies studied, 367 (74.3%) were found to have lead
present at levels ranging from 5-380 ug/1. There were 97 supplies with lead
exceeding 50 ug/1, the current MCL. The mean of the positive values was 42.8
ug/1 (standard deviation, 57.0 ug/1); the median value was 20.0 ug/1.
For surface water supplies, lead was observed in 108 of the 154 supplies
sampled (70.1%) at concentrations ranging from 5-164 ug/1 (Table 16). The
mean of the positives was 33.9 ug/1 (standard deviation, 37.5 ug/1); the
median value was 18.5 ug/1. There were 23 supplies reported to have values
exceeding 50 ug/1.
The reliability of the analytical results for lead presented in the RWS
have been called into question because of the seemingly high frequency of
occurrence of lead, especially at levels exceeding the MCL. It has been
suggested that some of the samples collected during this survey were contami-
nated with cadmium and lead during the sample preservation step. This, how-
ever, has not been confirmed (Coniglio 1984).
2.2.4 Compliance Monitoring Data
The Federal Reporting Data System (FRDS) provides information on public
water supplies found to be 1n violation of current MCLs as determined through
compliance monitoring of all supplies performed by the states under the
requirements of the National Interim Primary Drinking Water Regulations.
The data in FRDS (1984) indicate that there are currently 66 public water
supplies providing drinking water having lead levels above 50 ug/1, the
interim national primary drinking water MCL. As summarized in Table 17, 59 of
those supplies have a groundwater source, and most of those supplies are in
the small and medium size categories. Many of the supplies in violation had
lead levels 1n the range of > 50-100 ug/1; however, 14 supplies had values
exceeding 150 ug/1 (the highest from a supply in Delaware reporting 1,600
ug/1).
34
-------
Table 15. Reported Occurrence of Lead in Groundwater Systems Studied in the Rural Mater Survey
Number of systems with Measured concentrations (uq/l) of:
System size Number of
(population systems
served) studied
NegatIve
a
systems
2.5.0-
12.5
>12.5-
25.0
>25.0-
37.5
>37.5-
50.0
>50.0-
62.5
>62.5-
75.0
>75.0-
87.5
>87.5-
100.0
>100.0-
112.5
>112.5-
125.0
>125.0-
137.5
>137.5-
150.0
>150.0
25-100
51
15
16
9
3
4
0
1
1
2
0
0
0
0
0
101-500
B2
25
20
13
5
4
3
0
4
1
1
0
1
1
4
501-1,000
84
23
15
15
7
4
4
3
3
0
2
1
2
0
5
1,001-2,500
149
33
50
25
8
6
7
4
1
5
0
1
2
2
5
2,501-3,300
34
8
9
4
2
2
2
0
1
2
1
0
0
1
2
3,301-5,000
18
2
7
2
2
0
'
<
0
0
0
0
0
1
2
5,001-10,000
28
6
6
5
3
1
0
1
2
1
0
1
1
0
1
10,001-50,000
39
13
11
1
3
3
5
1
1
0
0
0
0
0
1
50,001-75,000
2
2
0
0
0
0
0
0
0
0
0
0
0
0
0
75,001-100,000
3
0
1
0
1
0
0
0
0
1
0
0
0
0
0
>100,000
4
0
3
0
0
0
0
0
0
0
J)
£
£
£
1
Total
494
127
138
74
34
24
22
11
13
12
4
3
6
5
21
aBelow the minimum quantifiable concentration of 5 ug/l.
-------
Table 16. Reported Occurrence of Lead in Surface Hater Systems Studied (n the Rural Mater Survey
Number of systems with Measured concentrations (ug/l) of:
System size Number of
(population systems
served) studied
Negative
systems
2.5.0-
12.5
>12.5-
25.0
>25.0-
37.5
>37.5-
50.0
>50.0-
62.5
>62.5-
75.0
>75.0-
87.5
>87.5-
100.0
>100.0-
112.5
>112.5-
125.0
>125.0-
137.5
>137.5-
150.0
>150.0
25-100
2
1
0
0
1
0
0
0
0
0
0
0
0
0
0
101-500
3
0
1
2
0
0
0
0
0
0
0
0
0
0
0
501-1,000
11
3
6
1
1
0
0
0
0
0
0
0
0
0
0
1,001-2.500
39
12
11
5
1
1
2
2
1
2
1
0
0
1
0
2,501-3,300
12
5
4
1
0
0
1
0
0
1
0
0
0
0
0
3,301-5,000
16
3
6
3
2
2
0
0
0
0
0
0
0
0
0
5,001-10,000
19
7
4
3
0
2
0
0
2
0
0
0
0
1
0
10,001-50,000
30
9
7
2
5
2
1
1
0
0
0
0
1
I
1
50,001-75,000
7
2
3
0
0
0
1
0
0
1
0
0
0
0
0
75,001-100,000
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
>100,000
14
3
_3_
3
1
7_
£
£
SL
£
£
£
£
J_
Total
154
46
45
20
It
9
6
3
3
4
1
0
1
3
2
sBelow the minimum quantifiable concentration of S ug/l.
-------
Table 17. National Summary of Lead Violations, Variations, and Exemptions
in Groundwater Systems
Analytical results for supplies
in violation (range, ug/1)
Population
served
Unknown
>50-
75
>75-
100
>100-
125
>125-
150
>150
Variances
and
exemptions
Totals
25-100
3
2
4
1
—
5
—
15
101-500
11
2
3
3
1
2
—
22
501-1,000
—
2
3
—
—
3
—
8
1,001-2,500
--
--
1
—
4
1
—
6
2,501-3,300
1
--
1
3,301-5,000
—
—
—
1
—
1
—
2
5,001-10,000
—
2
1
--
3
10,001-50,000
--
2
—
2
50,001-75,000
—
0
75,001-100,000
—
0
>100,000
_
zz.
zz.
ZZ.
zz.
_0
Total
14
10
11
5
5
14
--
59
Source: FRDS 1984
37
-------
The seven surface water supplies in violation of the lead MCL served
small, medium, as well as large populations. As summarized in Table 18, three
of the seven supplies exceeded 100 ug/1 (with reported values of 1,670, 2,260,
Table 18. National Summary of Lead Violations, Variations, and Exemptions
and 10,350 ug/1 from three supplies in Pennsylvania.
Table 18. National Summary of Lead Violations, Variations, and Exemptions
in Surface Water Systems
Analytical results for supplies
in violation (range, ug/1)
Variances
Population >50- >75- >100- >125- and
served Unknown 75 100 125 150 >150 exemptions Totals
25-100 — — 1 — i
101-500 — 0
501-1,000 — 0
1,001-2,500 - — 1 -- 1
2,501-3,300 -- 0
3,301-5,000 — 0
5,001-10,000 3 3
10,001-50,000 " 0
50,001-75,000 " 0
75,001-100,000 " 0
>100,000 ZZ. ± A — — — — 1
Total 0 1 3 0 0 3 — 7
Source: FRDS 1984
There are currently no supplies on record in FRDS as having a variance or
exemption from the lead MCL.
38
-------
2.3 SUMMARY OF DRINKING WATER OCCURRENCE OF LEAD
It is difficult to derive a clear picture of lead occurrence in public
water supplies based on the information collected. It appears that the
principal source of lead in drinking water as consumed by individuals using
public drinking.water supplies is the distribution system. The information
reviewed indicates that the level of lead in drinking water is higher in
samples taken where there is newly installed plumbing in the distribution
system using lead pipe or lead solder, together with corrosive water (i.e.,
low pH, alkalinity, and hardness). It is also evident that lead levels due to
the distribution system are higher in drinking water samples taken after
prolonged contact with the plumbing, such as overnight standing. Under cir-
cumstances favoring lead entering drinking water from the distribution system,
it does not appear unusual to observe lead levels above the current MCL,
particularly in first flush samples.
The available compliance monitoring data indicate that 59 groundwater and
7 surface water supplies in the United States are delivering lead with levels
above the current MCL of 50 ug/1. It is not known whether the observed MCL
violations are due to high lead levels in the source water or to lead added
from the distribution system.
The three national surveys provide limited insight to the national occur-
rence of lead in public water supplies. The 1969 CWSS, which is the oldest
data set, suggests that lead occurs 1n most public water supplies (90-95%),
with both mean and median concentrations of approximately 12 ug/1 for both
groundwater and surface water. Only one supply in the 1969 CWSS was reported
to have lead above the current MCL. The more recent Rural Water Survey also
indicates a high frequency of occurrence of lead (70-75%); however, the RWS
suggests that the mean of the positive values 1s considerably higher than that
observed 1n the 1969 CWSS, ranging from 34-43 ug/1. (Median values were 18-20
ug/1 in the RWS.) Also, the RWS suggested that 15-20% of supplies had values
exceeding the current MCL. As noted, however, the analytical reliability of
the RWS lead data have been questioned. The considerably smaller 1978 CWSS
data set provide results more comparable to the 1969 CWSS for surface water
(10.7 ug/1 mean value, none above the MCL) and more comparable to the RWS for
groundwater (30.3 ug/1 mean value, 9% above the MCL).
39
-------
None of the national surveys provided sufficient details about the actual
samples collected (characteristics of the distribution system; water corrosiv-
ity, etc.) to allow for a full assessment of the reported results. While it
seeins clear that lead is a frequent contaminant of drinking water received by
consumers using public water supplies, the factors affecting lead concen-
trations are too varied to arrive at a determination of typical levels of
occurrence.
40
-------
3. OCCURRENCE IN FOOD
The Food and Drug Administration (FDA) conducts Total Diet Studies
(Market Basket Surveys) to evaluate the occurrence of various substances,
including lead, in food consumed by adults, toddlers (2 years old), and
infants (6 months old) in the United States. The results for lead levels in
various food categories examined by the FDA for recent years are presented
here; Section 5.2 discusses the resulting dietary intake.
Table 19 identifies the 12 food class composites collected for the adult
diet by FDA and indicates the levels of lead observed in the Fiscal Year 1977
(FY 77) and Fiscal Year 1979 (FY 79) studies, as well as the frequency of
occurrence in the food composites (FDA 1980a, 1982a). In these studies, the
foods collected from 20-25 locations throughout the United States are prepared
in the manner in which they are usually consumed, combined to yield a homo-
genous mixture, and then analyzed. The results for lead are presented by FDA
as Pb. The data in Table 19 were calculated from the Information given in the
FDA reports on intake per day of each food category and intake of lead per day
within each food category. Table 20 presents similar data for the infant and
toddler food categories.
The highest concentrations for the FDA adult food composites were in the
legume vegetables and garden fruits categories. The highest concentrations
for the infant/toddler food composites occurred in the grain and cereal pro-
ducts, vegetables, and fruit and fruit juices categories, and also the sugar
and adjuncts category in the toddler study.
Some additional information on concentrations of lead in various food
sources was also obtained. Table 21 presents levels of lead detected in
various agricultural commodities in FY 77, as presented by FDA (1981).
According to FDA (1981), apples demonstrated a low level of lead in FY 77 as
has been shown 1n previous years as well. This is important as lead arsenate
pesticide was frequently used on apples in the past.
Table 22 presents background lead concentrations in basic food crops and
meats, and Table 23 presents lead concentrations in milk, foods, water, and
beverages. In Table 22, indirect atmospheric lead refers to the lead pre-
viously Incorporated into the soil (which will probably persist for decades)
and direct atmospheric lead refers to lead deposited on the vegetation (or
41
-------
Table 19. Levels of Lead in FDA Total Diet Study Food Composites
for the Adult
Food composite category
Lead levels
FY 77
(in ug/g Pb)
FY 79
Dairy products
0.0095 (10/25)a
0.0059 (3/20)
Meat, fish, and poultry
0.024 (16/25)
0.027 (18/20)
Grain and cereal products
0.029 (15/25)
0.048 (19/20)
Potatoes
0.038 (14/25)
0.031 (15/20)
Leafy vegetables
0.019 (13/25)
0.029 (15/20)
Legume vegetables
0.18 (25/25)
0.13 (19/20)
Root vegetables
0.049 (17/25)
0.040 (15/20)
Sarden fruits
0.14 (23/25)
0.10 (19/20)
Fruits
0.044 (21/25)
0.050 (20/20)
Oils, fats, and shortening
0.016 (11/25)
0.019 (8/20)
Sugar and adjuncts
0.029 (18/25)
0.036 (18/20)
Beverages (including drinking water)
0.012 (11/25)
0.015 (8/20)
aNumbers in parentheses are the number of composites with lead present over
the number of composites examined.
Source: FDA 1980a, 1982a
42
-------
Table 20. Levels of Lead in FDA Total Diet Study Food Composites for Infants and Toddlers (In ug/g Pb)
Food composite category
Infants
Toddlers
FY 77
FY 79
FY 77
FY 79
Drinking water
0.006 (1/12 )a
0.008 (5/10)
0.004 (1/12)
0.010 (5/10)
Whole milk, fresh
0.001 (1/12)
0.012 (4/10)
0.001 (1/12)
0.011 (4/10)
Other dairy and substitutes
0.019 (4/12)
0.030 (8/10)
0.015 (6/12)
0.013 (9/10)
Meat, fish, and poultry
0.021 (6/12)
0.030 (8/10)
0.029 (6/12)
0.041 (10/10)
Grain and cereal products
0.062 (7/12)
0.064 (9/10)
0.036 (8/12)
0.058 (10/10)
Potatoes
0.010 (4/9)
0.080 (5/10)
0.028 (8/12)
0.026 (5/10)
Vegetables
0.049 (6/12)
0.097 (10/10)
0.078 (9/12)
0.110 (10/10)
Fruit and fruit juices
0.067 (8/12)
0.061 (9/10)
0.052 (9/12)
0.067 ,(10/10)
Oils and fats
0.010 (5/3)b
0.014 (2/10)
0.019 (4/12)
0.016 (8/10)
Sugar and adjuncts
0.018 (5/12)
0.026 (7/10)
0.041 (7/12)
0.071 (10/10)
Beverages
0.052 (5/9)
0.015 (4/10)
0.018 (4/12)
0.022 (8/10)
aNumbers in parentheses are the number of composites with lead present over the number of composites
examined.
bThe frequency of lead in oils and fats in the FY 77 infant survey was reported as five positive composites
out of three examined. This discrepancy is not explained in the FDA report (FDA 1980b).
Source: FDA 1980b, 1982b
-------
Table 21. Distribution of Lead Levels Detected in Various Domestic Raw Agricultural Commodities in FY 77
Number (%) of samples in each level
Commodity
No. of
samples
None
detected
Trace
0.1a-0.29
ppm
0.3-0.49
ppm
>0.
50 ppm
Hi ghest
level
reported
(ppm)
Soybeans
36
5 (13.9)
19 (52.8)
9 (25.0)
3 (8.3)
0
0.36
Peanuts
12
3 (25.0)
1 (8.3)
4 (33.3)
1 (8.3)
3 (25.0)
0.85
Potatoes
48
22 (45.8)
17 (35.4)
9 (18.8)
0
0
0.21
Onions
36
23 (63.9)
13 (26.1)
0
0
0
Trace
Lettuce
32
2 (6.3)
20 (62.5)
9 (28.1)
1 (3.1)
0
0.33
Cabbage
47
7 (14.9)
35 (74.5)
4 (8.5)
1 (2.1)
0
0.34
Corn
36
25 (69.4)
9 (25.0)
2 (5.5)
0
0
0.29
Peas
40
5 (12.5)
23 (57.5)
11 (27.5)
0
1
(2.5)
1.17
Apples
36
19 (52.8)
14 (38.9)
3 (8.3)
0
0
0.17
Beans
42
18 (42.9)
21 (50.0)
3 (7.1)
0
0
0.14
Tomatoes
60
21 (35.0)
14 (23.3)
22 (36.7)
3 (5.0)
0
0.44
Wheat
36
1 (2.8)
20 (55.6)
13 (36.1)
1 (2.8)
J_
(2.8)
0.81
Totals
461
151 (32.8)
206 (44.7)
89 (19.3)
10 (2.2)
5
(1.1)
a0.1 ppm = quantitation limit.
Source: FDA 1981
-------
Table 22. Background Lead in Basic Food Crops and Meatsa
Crop
Natural Pb
Indi rect
atmospheric
Di rect
atmospheric
Totalk
Wheat
0.0015
0.0015
0.034
0.037
Potatoes
0.0045
0.0045
—
0.009
Field corn
0.0015
0.0015
0.019
0.022c
Sweet corn
0.0015
0.0015
—
0.003
Soybeans
0.021
0.021
—
0.042
Peanuts
0.050
0.050
—
0.100
Onions
0.0023
0.0023
—
0.0046c
Rice
0.0015
0.0015
0.004
0.007c
Carrots
0.0045
0.0045
—
0.009°
Tomatoes
0.001
0.001
—
0.002°
Spinach
0.0015
0.0015
0.042
0.045°
Lettuce
0.0015
0.0015
0.010
0.013
Beef (muscle)
0.0002
0.002
0.02
0.02d
Pork (muscle)
0.0002
0.002
0.06
0.06d
aAll units are In ug/g fresh weight.
''Except as indicated, data are from Wolnick et al. (1983).
Preliminary data provided by the Elemental Analysis Research Center, Food and
Drug Administration, Cincinnati, Ohio.
dData from Penumarthy et al. (1980).
Source: USEPA 1983
45
-------
Table 23. Lead Concentrations in Milk, Food, Water, and Beverages
Pnduct Lead concentration (ug/g)
Milk and foods
Milk 0.01
Dairy products 0.03
M1lk as ingredient 0.01
Beef 0.035
Pork 0.06
Chicken 0.02
Fish 0.09
Prepared meats 0.013
Other meats 0.07
Eggs 0.017
Bread 0.015
Flour as Ingredient 0.013
Non-wheat cereals 0.025
Corn flour 0.025
Leafy vegetables 0*05
Root vegetables 0.025
Vine vegetables 0.025
Canned vegetables 0*25
Sweet corn °*01
Canned sweet corn
Potatoes
Water and beverages
Canned juices
Frozen juices
Canned soda
0.21
0.02
Vegetable oil °*03
Sugar 0,03
Canned fruits
Fresh fruits
Pureed baby food
0.22
0.02
0.03
0.052
0.02
0.033
46
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Table 23. Lead Concentrations in Milk, Food, Water, and Beverages
(continued)
Product
Lead concentration (ug/g)
Water and beverages (cont'd)
Bottled soda
0.02
Coffee
0.01
Tea
0.01
Canned beer
0.017
Wine
0.01
Whiskey
0.01
Water
0.008
Water as ingredient
0.008
Source: USEPA 1983
47
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incorporated into the food during processing) just before consumption (USEPA
1983). The levels presented for lead in various agricultural crops by FDA
(Table 21) are higher than those presented for corresponding crops by EPA
(Table 22). However, given the magnitude of the values presented in Table 22,
the limit of detection for the EPA study was probably lower than the FDA
quantitation limit of 0.1 ppm for lead. it is also worth noting that the
highest lead concentrations presented in Table 23 are for products that have
been canned (i.e., canned vegetables, sweet corn, fruits, juices, and soda).
This is probably due to the leaching of lead solder used in the manufacture of
cans (USEPA 1980).
Table 24 indicates the distribution of lead levels in canned domestic
tuna, as was presented 1n the FDA FY 79 Compliance Program Report of Findings
for the Pesticides and Metals in F1sh Program (FDA 1982c). There are cur-
rently no regulatory guidelines for lead in fish.
Table 24. Distribution of Lead Levels in Canned Domestic Tuna
Interval, ppm
Number of samples in interval
Zero or not detected
7
T (< 0.02)
8
0.02-0.10
29
0.11-0.30
18
0.31-0.50
7
0.51-0.70
7
0.71-0.90
4
>0.91
8
Average (88 samples) * 0.28.
Minimum level quantltated * 0.02 ppm.
Maximum level ¦ 1.54 ppm.
T » Trace (< 0.02 ppm limit of quantitation).
No regulatory limit has been established for lead in fish.
Source: FDA 1982c
48
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4. OCCURRENCE IN AMBIENT AIR
As discussed earlier (Section 1.1.5), lead is introduced into the atmo-
sphere by both natural and anthropogenic means. Because natural lead is
generally three to four orders of magnitude lower than anthropogenic lead in
ambient rural or urban air, essentially all atmospheric contributions of lead
are considered to be of anthropogenic origin (USEPA 1983). Lead concentra-
tions in ambient air that are in the pathway to human intake were summarized
in USEPA (1983), and are presented below:
Urban air: 0.8 ug/m3
Rural air: 0.2 ug/m3
According to USEPA (1983), typical urban atmospheres contain 0.5-1.0
ug/m3 of lead. However, Table 25 presents data from various urban locations,
as well as some rural and remote locations, with slightly higher values.
Although USEPA (1983) reported no particular trend in ambient air concen-
trations of lead from 1965 to 1977, some data show that decreases have
occurred in recent years. Mean urban air lead concentrations reported from
National Filter Analysis Network (NFAN) stations have apparently dropped from
an estimated 0.91 ug/m3 in 1977 to 0.32 ug/m3 in 1980. Although the number of
reporting stations has also dropped since 1977, these decreases also reflect
the smaller lead emissions from mobile sources in recent years (USEPA 1983).
Although lead may be ubiquitous in the atmosphere, the highest levels are
reported in areas where industrial manufacturing, smelting, and refining
facilities are operating. Ambient air concentrations within 2 km of lead
smelters and refineries average 5-15 ug/m3 (USEPA 1983).
The most comprehensive information obtained on ambient air concentrations
of lead in the United States was provided by the USEPA National Air Surveil-
lance Network (NASN), which is a data base of monitored stations (USEPA
1984). Ambient air at most stations sampled by the NASN between 1977 and 1983
contained some amount of lead. Table 26 summarizes the results of that
survey. The overall range of mean values was from 0.002-3.854 ug/m3; the
overall range of median values was from 0.006-3.92 ug/m3. The highest value
reported for all survey years and all 411 survey sites (22,730 samples) was
9.68 ug/m3 from a site in Minneapolis, Minnesota.
49
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Table 25. Atmospheric Lead in Urban, Rural, and Remote Areas
of the United States3
Lead
Sampling concentration
Location period (ug/m3) Reference
Urban
Miami 1974 1.3 a
New York 1978-79 1.1 b
Boston 1978-79 0.8 b
St. Louis 1973 1.1 b
Houston 1978-79 0.9 b
Chicago 1979 0.8 b
Salt Lake City 1974 0.89 a
Los Angeles 1978-79 1.4 b
Rural
New York Bight 1974 0.13 a
Framingham, MA 1972 0.9 a
Chadron, NE 1973-74 0.045 a
Remote
White Mountain, CA 1969-70 0.008 a
High Sierra, CA 1976-77 0.021 a
Olympic National Park, WA 1980 0.0022 a
aL1sted 1n USEPA 1983 from Nriagu 1978.
bData from the National A1r Surveillance Network, Research Triangle Park, NC,
as reported in USEPA 1983.
50
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Table 26. Occurrence of Lead in Ambient Aira
Location
Range
of
years
Number
of
sites
Number
of
samples
Range
of means
(ug/m3)
Maximum
level
(ug/m3)
Range of
medians
(ug/m3)
AT abama
1977-1981
10
524
0.1480-1.103
3.43
0.20-0.328
Alaska
1977-1980
3
123
0.368-1.426
4.30
0.37-0.86
Arizona
1977-1983
5
510
0.0020-1.424
5.42
LD-1.21
Arkansas
1977-1982
6
197
0.0175-0.678
1.80
0.019-0.73
California
1977-1982
21
1,626
0.080-2.957
7.48
0.08-2.45
Colorado
1977-1983
4
97
0.0039-1.065
3.64
LD-0.86
Connecticut
1977-1980
6
285
0.547-1.963
6.64
0.42-1.77
Delaware
1977-1983
4
156
0.106-1.497
3.07
0.08-1.40
District of
1977-1982
1
39
0.329-0.384
1.16
0.29-0.33
Columbia
Florida
1977-1982
13
731
0.0447-1.094
2.72
1.09-0.041
Georgia
1977-1983
3
282
0.126-1.205
3.28
0.12-1.03
Hawai i
1977-1982
2
226
0.0020-0.717
2.12
LD-0.78
Idaho
1977-1981
2
109
0.0115-0.783
1.82
0.009-0.71
Illinois
1977-1981
11
250
0.193-0.832
1.99
0.15-0.74
Indiana
1977-1982
20
1,052
0.0270-1.603
5.21
0.021-1.08
Iowa
1977-1982
10
645
0.046-0.737
1.83
0.03-0.71
Kansas
1977-1982
7
423
0.190-0/695
1.89
0.06-0.60
Kentucky
1977-1983
8
459
0.130-1.179
3.88
0.04-0.96
Louisiana
1977-1983
5
518
0.047-1.154
4.26
0.04-0.95
Maine
1977-1981
3
199
0.0269-0.453
1.31
0.022-0.38
Maryland
1977-1983
4
228
1.067-0.0792
2.50
0.055-0.97
Massachusetts
1977-1981
11
554
0.235-1.462
8.41
0.14-1.02
Michigan
1977-1982
10
395
0.122-0.999
2.42
0.12-0.96
Minnesota
1977-1981
7
356
0.144-1.723
9.68
0.11-0.97
Mississippi
1977-1982
3
132
0.1258-0.836
2.05
0.116-0.68
Missouri
1977-1978
4
84
0.0857-1.076
1.91
0.073-0.93
Montana
1977-1978
5
116
0.0078-0.534
Z. 94
LD-0.26
Nebraska
1977-1982 .
5
264
0.0195-1.080
5.71
0.013-0.82
Nevada
1977-1982
4
459
0.0020-1.487
4.38
LD-1.02
New Hampshire
1977-1980
2
122
0.0279-0.518
1.29
0.022-0.39
51
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Table 26.
Occurrence of Lead in Ambient
(continued)
Aira
Location
Range
of
years
Number
of
sites
Number
of
samples
Range
of means
(ug/m3)
Maximum
level
(ug/m3)
Range of
medians
(ug/m3)
New Jersey
1977-1982
14
1,073
0.150-2.053
4.86
0.13-1.58
New Mexico
1977-1982
1
118
0.381-1.267
4.13
0.32-0.92
New York
1978-1982
20
848
0.0240-1.307
2.58
0.017-1.18
North Carolina
1977-1983
10
709
0.051-1.152
4.03
0.04-1.03
Ohio
1977-1983
16
1,688
0.043-0.976
3.87
0.03-0.83
Oklahoma
1977-1983
4
170
0.070-0.530
1.25
0.07-0.50
Oregon
1977-1983
4
216
0.0190-0.833
4.23
0.012-0.63
Pennsylvania
1977-1983
29
914
0.068-2.051
5.29
0.07-1.83
Puerto Rico
1977-1982
13
621
0.058-3.854
6.30
0.055-3.92
Rhode Island
1977-1980
6
209
0.0475-1.256
4.28
0.023-1.13
South Carolina
1977-1982
9
307
0.1526-1.046
3.45
0.146-0.73
South Dakota
1977-1982
4
152
0.0068-0.512
1.62
LD-0.39
Tennessee
1977-1983
13
636
0.0852-1.787
5.57
0.081-1.72
Texas
1977-1980
16
811
0.585-1.849
5.12
0.041-1.45
Utah
1977-1983
2
104
0.966-1.548
7.88
0.73-1.16
Vermont
1977-1981
2
134
0.0343-0.794
1.14
0.041-0.75
Virginia
1977-1983
17
884
0.0743-0.968
3.75
0.075-0.83
Washington
1977-1982
6
580
0.202-1.464
3.14
0.16-1.31
West Virginia
1977-1983
5
172
0.208-1.205
6.86
0.012-0.88
Wisconsin
1977-1983
15
958
0.0227-0.943
2.26
LD-0.85
Virgin Islands
1977-1983
3
183
0.0131-0.1856
0.630
0.006-0.167
Wyoming
1977-1983
3
82
0.0029-0.283
0.56
LD-0.19
aThe analytical method used was high voltage JA emission spectroscopy.
LD » Less than detection limit.
Source: USEPA 1984
52
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Also of importance are lead concentrations in dusts. Dusts have been
defined as solid particles that are produced by the disintegration of
materials (Friedlander 1977, as cited in USEPA 1983). There are no size
limitations, and dusts should be described both in terms of concentrations and
amounts; the relative concentrations of rural street dust and urban street
dust may be the same, but the amount of dust could vary greatly (USEPA
1983). According to EPA (USEPA 1983), ingestion, not inhalation, is the
primary source of human exposure, especially ingestion during meals and during
play activities in the case of children. The major sources for human expousre
are from household dusts, street dust, and occupational dust, with dust lead
concentrations of 300 ug/g, 90 ug/g, and 150 ug/g, respectively.
53
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5. HUMAN EXPOSURE FROM DRINKING WATER, FOOD, AIR, AND DUST
5.1 DRINKING WATER INTAKE
Based on the available information presented in Chapter 2, it is diffi-
cult to arrive at an estimate of the typical or representative intake of lead
from drinking water. The compliance monitoring data provided through FRDS
suggests that there are only 66 public water supplies delivering drinking
water having lead levels above the current MCL of 50 ug/1. Those supplies
serve a total of approximately 535,000 people, which is less than 0.3% of the
total population served by public water supplies. However, other data avail-
able indicate that the occurrence of lead in drinking water at the tap is
primarily influenced by the characteristics of the distribution system,
including the age of the plumbing in a residence. It 1s not clear that the
compliance monitoring data accounts for such factors. Consequently, it is
possible that more individuals using public water supplies are exposed to
levels above the MCL, at least on occasion, than 1s suggested by the FRDS
data.
The Federal survey data indicate that most drinking water has some lead
present and that the mean and median lead levels range from approximately
10-40 ug/1. The higher values are from the Rural Water Survey, for which the
reliability of the lead results have been questioned. Craun and McCabe
(1975), as cited in NAS (1977), Indicate that the average lead concentration
In tapwater 1s 13 ug/1, resulting in an intake of 26 ug/day for adults, assum-
ing a daily consumption of 2 1/day of drinking water. The EPA (USEPA 1983)
uses a representative value of 8 ug/1 for drinking water which, assuming a
consumption of 2 1/day, would result 1n an intake of 16 ug/day for adults.
[Note: Using FDA dietary Information, EPA (USEPA 1983) estimated a total lead
intake of 18.9 ug/day for adult males from the consumption of approximately
1.8 1/day of drinking water and beverages; this estimate includes the contri-
bution of lead added to canned and bottled beverages from solder and other
packaging procedures.]
EPA (USEPA 1983) indicates that the gastrointestinal absorption rate of
lead for adults ranges from 10-15%; for children, the absorption rate is
estimated to be 50%.
54
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5.2 FOOD INTAKE
Several estimates of dietary intake of lead in the United States have
been reported for recent years. The Food and Drug Administration includes
lead among the contaminants analyzed for in its Total Diet Studies (Market
Basket Surveys).. Table 27 presents the daily intake estimates for the adult
male for several years as reported in recently published Total Diet Studies
(FDA 1980a, 1982a). There is no apparent trend in the intake of lead for
FY 74-79. However, it should be noted that these findings are much lower than
the value reported by FDA (1980a) for lead in the FY 74 Metals in Foods Survey
of 254 ug/day. All of these daily Intake values are within the Provisional
Tolerable Daily Intake (PTDI) limit of 429 ug/day derived by the United
Nations' Food and Agriculture Organization and World Health Organization
(FA0/WH0). The FY 79 daily intake for the adult male of 81.7 ug/day is about
19% of the PTDI.
Table 27. Summary of FDA Total Diet Study Estimates for Lead Intake
for the Adult Male
Fiscal year
Intake (ug/day)
1979
81.7
1978
95.1
1977
79; 3
1976
71.1
1975
67.2
1974
90.2
Source: FDA 1980a, 1982a
Lead occurs naturally in the food supply; consequently, the detection of
lead in most of the food groups In the Total Diet Studies is to be expected.
In fact, lead was detected in all of the food groups. The food groups with
the largest percentages for the FY 79 daily intake of lead, excluding the
beverages category, were grains and cereals (27.4%), fruits (15.6%), and
legume vegetables (13.4%)". Some of the other food groups were relatively
Insignificant contributors of lead to the diet, including the root vegetables,
oils and fats, leafy vegetables, and sugars and adjuncts groups, which contri-
55
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buted 1.7%, 1.9%, 2.2%, and 4.1%, respectively (FDA 1982a). Table 28 shows
the relative daily intake of lead by each food composite category.
Table 28. Daily Intake of Lead for the Adult Male by Food Composite Category
Food composite category
Intake (in ug/day)
Dairy products
4.48
Meat, fish, and poultry
6.96
Grains and cereals
19.55
Potatoes
4.87
Leafy vegetables
1.61
Legume vegetables
9.56
Root vegetables
1.21
Garden fruits
7.72
Fruits
11.13
Oils and fats
1.38
Sugar and adjuncts
2.95
Beverages
10.27
Totals
Including beverages
81.69
Excluding beverages
71.42
Source: FDA 1982a
FDA (1982a) also noted a
geographic difference in lead intake for the
adult male:
Region
Intake (ug/day)
Northeast
86.3
North Central
70.0
South
104.6
West
65.8
There was no explanation suggested by FDA (1982a) for the higher lead intake
in the South region. It. should be emphasized that regional comparisons of
findings are very limited because of the small number of market baskets
sampled from each region, as well as by regional differences in composition of
56
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the market baskets and prevalence of various foods in the marketplace (FDA
1982a).
Total diet studies are also conducted by FDA for infants (6 months old)
and toddlers (2 years old). The results of the most recent studies are shown
in Table 29. The primary contributor to lead intake by toddlers in FY 79 was
the fruit and fruit juices category, accounting for 22.2% of intake. Also of
relative significance were the vegetables, grain and cereal products, whole
milk, and the meat, fish, and poultry categories, which accounted for 17%,
14.8%, 12.6%, and 11.3% of intake, respectively. There is some similarity
here of the predominant contributors of lead as compared with the major food
contributors of lead in the adult study, specifically the fruit and grain and
cereal categories.
Table 29. Summary of Total Diet Study Estimates for Lead Intake
for Infants and Toddlers
Intake (ug/day)
Fiscal year
Infant (6 months old)
Toddler (2 years old)
1979
36.2
45.8
1978
25a
35a
1977
22.1
27.8
1976
26.9
30.1
1975
20.8
25.6
aThe values presented in FDA (1982b) for daily intake of lead in FY 78 were
rounded off to whole numbers.
Source: FDA 1980b, 1982b
In the case of 6-month-old infants, the major intake sources in FY 79
were the vegetables, whole milk, and fruit and fruit juices categories,
accounting for 26.8%, 23.3%, and 22.7% of intake, respectively.
The maximum acceptable intake of lead from all sources (including air and
pica) recommended by the FDA Bureau of Foods is 100 ug/day for infants and 150
ug/day for toddlers (FDA 1982b). The daily lead intakes for both infant and
toddler diets are well below these current acceptable limits. Although the
lead intake in both the 6-month-old infant and toddler diets appears to have
57
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increased from FY 77 to FY 79, it cannot be determined whether this increase
is a trend.
FDA (1982b) also noted geographic differences in lead intake for infants
and toddlers:
Intake (ng/day)
Region Infant Toddler
Northeast 54.8 48.8
North Central 31.0 54.5
South 31.5 44.7
West 20.8 29.5
As can be seen above, the average dafly intake was highest for infants in the
Northeast region and highest for toddlers in the North Central region. Intake
was lowest for both infants and toddlers in the West region. No explanation
was presented in FDA (1982b) for these geographic differences in intake.
Again, these findings are limited because of the small number of market
baskets sampled from each region, as well as variations in the commodities
that comprise the market baskets.
EPA (USEPA 1983) has estimated that the dietary intake of lead from food
(excluding water and beverages) is 35.8 ug/day for the adult male and 18.9
ug/day for the 2-year-old child, based on more recent (unpublished) FDA data.
As indicated in Section 5.1, the gastrointestinal absorption rate for
lead ranges from 10—15% for adults and 50% for children (USEPA 1983).
5.3 RESPIRATORY INTAKE
EPA (USEPA 1983) indicated that atmospheric concentrations of lead in
urban and rural environments are 0.8 ug/m3 and 0.2 ug/m3, respectively.
However, USEPA (1983) calculated adjusted air lead concentrations to account
for the'indoor/outdoor ratio of lead for estimating baseline exposures. Those
levels are 0.10 ug/m3 for adults working outside, and 0.05 ug/m3 for adults
working Inside and 2-year-old children. Based on the 0.05 ug/m3 value, USEPA
(1983) has estimated that the baseline inhaled air exposure to lead 1s 1.0
ug/day for adults and 0.5 ug/day for the 2-year-old child.
The absorption rate of lead 1n respiratory exposure 1s Indicated by USEPA
(1983) to be 30-50S for adults, which 1s a function primarily of the rate of
58
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deposition of inhaled air in the lungs. EPA (USEPA 1983) notes that the
respiratory uptake rate in children may be greater on a body weight basis
compared to adults, due to relative airway dimensions.
5.4 INTAKE FROM DUST
EPA (USEPA 1983) has estimated that the intake of lead by children from
exposure to dust is 21 ug/day, comprised of household dust (15 ug/day), street
dust (4.5 ug/day), and occupational dust through contaminated clothing brought
home by parents (1.5 ug/day). In contrast, the total exposure of the adult
male to lead in dust is estimated to be only 4.5 ug/day, comprised of 3 ug/day
household dust and 1.5 ug/day occupational dust.
According to EPA (USEPA 1983), it is the ingestion of dust particles,
rather than inhalation, that appears to be of significance to estimating
baseline exposure. This is especially true for small children ingesting dust
during meals and playtime activity.
59
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6. RELATIVE SOURCE CONTRIBUTION
Table 30 presents an illustrative relative source contribution assessment
for lead in the 70-kg adult male. The estimated absorbed dose from air, 0.007
ug/kg/day, is based on the EPA estimate of a baseline adult intake of 1.0
ug/day and an absorption rate of 50% (USEPA 1983). The food dose is based on
the intake of 35.8 ug/day presented in USEPA (1983) and an absorption rate of
15%. Also included is an estimated intake of 4.5 ug/day from dust, also with
an absorption rate of 15%. The drinking water levels presented are a range of
values representative of those found in the Federal survey and FRDS data
presented in Chapter 2.
The major sources of absorbed lead for the adult male appears to be food
and drinking water. Food is the predominant source when drinking water levels
are below approximately 20-25 ug/1; however, at higher levels drinking water
predominates. At the current MCL of 50 ug/1, drinking water would be respons-
ible for about 70% of the absorbed dose for an adult male.
One special population for whom drinking water 1s an Important source is
newborn formula-fed infants. For this group, ingested dust would not appear
to be a significant source of Intake. Assuming an air level of 0.05 ug/m3
(USEPA 1983), a ventilation rate of 0.8 m3/day (ICRP 1974), and a respiratory
absorption rate of 50%, air would contribute a dose of 0.02 ug/day for the
newborn infant, or 0.0057 ug/kg/day, assuming a body weight of 3.5 kg.
Data provided by Conlglio (1984) suggest that liquid concentrate formula
has 0.03 ppm lead present. Assuming a total fluid intake of 0.85 1/day,
comprised of half formula concentrate and half drinking water, and an absorp-
tion rate of 50%, the liquid concentrate provides a daily lead dose of 6.4 ug,
or 1.8 ug/kg/day.
For newborn formula-fed Infants, drinking water would contribute a dally
lead dose equivalent to that received from the formula concentrate and air
when drinking water lead levels are approximately 30 ug/1. It Is Important to
note that for the Infant, the dose received on a body weight basis is approxi-
mately an order of magnitude greater than the dose received by an adult
exposed to a given level of lead 1n drinking water. For example, at the
current MCL of 50 ug/1, drinking water contributes an absorbed dose of 3.0
ug/kg/day for the newborn formula-fed Infant, compared to an absorbed dose of
0.21 ug/kg/day for the adult male.
60
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Table 30. Illustrative Relative Source Contribution Assessment for the
70-kg Adult Male: Total Dose (ug/kg/day) from Drinking Water, Air, and Food
and Percent from Drinking Water
Drinking water
concentration
(ug/1)
Drinking
water intake3
(ug/kg/day)
Assumptions for food and air
(Food intake: 0.077 ug/kg/davb;.
air intake: 0.007 ug/kg/dayt:
dust intake: 0.0096 ua/ka/davd)
Total intake
(ug/kg/day)
% from
drinking water
0
0
0.094
0
0.5
0.002
0.096
2.1
5
0.021
0.12
18.2
10
0.043
0.14
31.4
25
0.11
0.20
55.0
50
0.21
0.30
70.0
75
0.32
0.41
78.0
150
0.64
0.73
87.7
1,500
6.4
6.5
98.5
aAssumes 2 liters per day consumption; 15% absorption.
^Assumes a food intake of 35.8 ug/day; 15% absorption.
cAssumes a respiratory intake of 1.0 ug/day; 50% absorption.
^Assumes an intake of 4.5 ug/day; 15% absorption.
61
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REFERENCES
Battye B. 1983. Lead emissions inventory, January 31, 1981 [memo to John
Haines]. Available for inspection at Environmental Criteria and Assessment
Office, U.S. Environmental Protection Agency, Research Triangle Park, NC.
Cited in USEPA 1983.
Bowen HJM. 1966. Trace elements in biochemistry. London: Academic Press.
Brass H. 1983. U.S. Environmental Protection Agency, Office of Drinking
Water, Technical Support Division, Cincinnati, Ohio. Personal communication
with F. Letkiewicz, JRB Associates.
Britton LJ, Goddard KE, Briggs JC. 1983. Quality of rivers of the United
States, 1976 water year -- Based on the National Stream Quality Accounting
Network (NASQAN). U.S. Geological Survey. Open File Report 80-594.
Brower B. 1983. Computer data file of analytical results for public water
supplies sampled in the Rural Water Survey. Cornell University, Department of
Rural Sociology.
Cannon HL. 1976. Lead in vegetation. In: Lovering TG (ed.). Lead in the
environment. U.S. Geological Survey professional paper 957. Washington,
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