United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S2-90/056 Feb. 1991
EPA Project Summary
Impact of Lead and Other
Metallic Solders on Water Quality
Norman E. Murrell
A study of the relationship between
water quality at the consumer's taps
and the corrosion of lead solder was
conducted under actual field conditions
in 90 homes supplied by public water in
the South Huntington Water District
(New York) and at 14 houses supplied
by private wells in Suffolk County on
Long Island (New York). The South
Huntington Water District water supply
is composed of wells that feed water to
a series of storage tanks from which
water is distributed to individual homes.
The 90 homes were selected to provide
110 sites of 9 house construction age
groups—from new to those more than
20 years old.
The study was done in three phases
at three different pH ranges (5.0-6.8, 7.0
to 7.4, and 8.0 and greater). The phase I
study was performed without any pH
adjustments on the water sources. The
pH range of the water from the South
Huntington District was 5.1 to 6.4,
whereas the water from the private wells
in Suffolk County had a pH range of 5.6
to 6.8. Phase II study consisted of rais-
ing the pH to the 7.0 to 7.4 range by the
addition of caustic soda and maintain-
ing the pH for 30 days prior to the
sampling. Only the South Huntington
Water Supply district participated in this
phase; the private wells in Suffolk
County were not treated. Similarly, the
pH was increased to 8.0 and greater for
the Phase III study. It was difficult to
hold the pH at 8.0 due to the unbuffered
water source. Water samples were col-
lected from an inside faucet within each
home after an overnight period of
nonuse. Eight 125-mL samples were
collected at specific time intervals in
order to evaluate the effect of time on
the leaching rate of lead. All eight
samples were analyzed for lead and the
first draw sample was analyzed for cad-
mium and copper. Water that was col-
lected between the 125-mL samples was
analyzed for pH, alkalinity, hardness
chlorides, and total dissolved solids.
The Langelier Saturation Index was cal-
culated from these parameters.
In the second phase of the investi-
gation, a more controlled, four-pipe loop
study was conducted with the same
corrosive Long Island water. Each pipe
loop consisted of approximately 60 ft of
copper pipe with 22 solder joints, each
loop having a different type of solder:
(1) tin/lead, (2) tin/antimony, (3) silver/
copper, and (4) tin/copper. The four loop
solder test results indicate that tin/anti-
mony, silver/copper, and tin/copper can
be used with only minor metal leaching.
This Project Summary was devel-
oped by EPA's Risk Reduction Engi-
neering Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
In October 1982, a western Suffolk
County (New York) Water District consumer
in Smithstown, NY, complained of lead
poisoning. At that time, water as a source
of lead was discounted since the Water
Printed on Recycled Paper
-------
District had a 15-yr record of lead-free
distribution samples—a record obtained by
using the standard procedure of running
the water 3 to 5 min before sampling. Two
separate water samples obtained by the
complainant without flushing the system
showed lead levels of 1900 and 1600 u.g/L.
An additional water sample, collected after
running the water for 3 to 5 min, showed a
lead level of 27 u,g/L. Another series of
water samples was collected after a 4-hr
nonuse period and the results of the lead
analysis on these samples are shown in
Figure 1. By this time, lead solder in the
copper plumbing was suspected as the
source of the lead. Tests of nearby homes
indicated that lead was also present in
these plumbing systems. As a result of this
information, a lead solder ban was ap-
proved and made effective immediately in
the town of Smithtown on December 26,
1982.
Additional testing for lead (done for the
Nassau and Suffolk County Health Depart-
300
Lead in Water
Sample
ments and the Town of Hempstead) pro-
duced data showing high lead concentra-
tions in first draw samples. These data
along with suggestions for further research
focusing on the effect of age of the plumb-
ing, and the pH and hardness of the water
supply on leaching lead from lead solder
resulted in this cooperative study of the
U.S. Environmental Protection Agency and
the South Huntington Water District.
Procedures
To develop an understanding of the
effects of water chemistry, plumbing system
age, and solder type on lead leaching, a
work plan was developed to observe these
effects in individual homes that were cho-
sen in various age categories. The solder
in the plumbing system of each house was
analyzed for the presence of lead. Since
copper plumbing systems are almost ex-
clusively connected by lead solder, the
field sampling was supplemented with an
evaluation of specially constructed pipe
loops to evaluate leaching from alternative
solders.
The homes tested were located in the
South Huntington Water District and in
Suffolk County on Long Island, NY. The
South Huntington Water District water
supply is composed of wells that feed wa-
ter to a series of storage tanks from which
the water is distributed to individual homes.
The Suffolk County homes were served by
private wells. Household water testing was
50 ug/L Drinking
Water Standard
50
I I I I I I I I
0 10 20 30 40 50 60 70 80
Time (sec)
Figure 1. Time series lead sample in upstairs bedroom bathroom Smithtown residence.
2
conducted in three phases at three differ-
ent pH values to test the effect of pH
changes on lead leaching. In Phase I, 63
homes in the South Huntington Water Dis-
trict and 14 homes in Suffolk County were
tested at the pH range of 5.0 to 6.8. The
water in Suffolk County had a pH range of
5.6 to 6.8, whereas the pH in the South
Huntington was pH 6.4 and less (see Table
8). Because the pH of the private wells in
Suffolk County could not be modified, 27
more homes in the South Huntington Wa-
ter District were added to the 63 homes for
the Phase II study. The pH was raised to
between 7.0 and 7.4 for the Phase II study.
In Phase III, the pH was raised to greater
than 8.0. Four households declined to
participate in the Phase III study so that
the total sampled was reduced to 86.
Homes were selected so that approximately
an equal number of homes fell into the
following nine age categories: 0-1; 1-2;
2-3; 3-4; 4-5; 6-7; 9-10; 14-17; >20 yr of
age. These homes were also selected to
provide a reasonable geographic distribu-
tion of the customers in South Huntington.
To evaluate the lead leaching with re-
spect to length of sampling time at each
home, eight 125-mL samples were col-
lected from a continuously flowing faucet
after first removing the faucet strainer. The
sampling sequence is shown in Table 1.
Table I. Sampling Sequence
Time After First Draw
Sampling Sequence (Sec)
0 (first draw)
10
20
30
45
60
90
120
Water coming out of the faucets be-
tween each 125-mL sample was caught in
a container to obtain a volume figure and
for some of the chemical analyses. Figure
2 shows a schematic of the time series of
samples that were utilized in the study.
The flow rate for sampling was 1800 mL/
min. The length of time for each sample
and period of time between samples is
shown in this figure. All of the samples
were analyzed for lead with the use of the
atomic absorption graphite furnace tech-
nique. Cadmium and copper were deter-
mined in the first draw samples; the water
caught between samples (2600 mL) was
used to determine other water quality pa-
rameters such as pH, Langelier Saturation
-------
120
125-mL Sample
90
60
45
30
20
10
0
125-mL Sample \
125-mL Sample \
125-mL Sample \
125-mL Sample \
125-mL Sample J
125-mL Sample \
-------
WO"
Working Length
ti
Floor
Figure 3. Schematic Drawing of typical loop in four loop study.
was done in which the water had 42.5 u,g/L
in the first draw sample and 3.0 u.g/L for
the second draw sample. Subsequent
samples reached the detection limit of 1
|j.g/L by the sixth draw. The results suggest
that the cadmium came from the faucet.
Copper leaching studies were also done
on the test sites. At a pH of 6.4 and less,
82.4% exceeded the proposed maximum
contaminant limit (MCL) of 1.3 mg/L on the
first draw sample from the South Hunting-
ton Water District. Only one exceeded 1.3
mg/L at a pH above 7.0.
In the pipe loop studies, four loops
employing four types of solder were con-
structed to provide a means of comparing
the leaching of tin/lead solder with that of
three possible substitute solders. The four
control loops were constructed by the same
plumber with the same number of joints at
the same spacing. The same corrosive
Long Island groundwater was used as in
the home testing program. Water was left
standing in the loops for varying periods of
time. The average lead content and major
components of the solders used in the
pipe loop study are listed in Table 7.
The general loop testing procedure be-
gins with adding water to the top of the
loop. The water is allowed to stand for a
specific period of time and then removed
at the bottom. The pH is checked on the
influent water after the time period has
elapsed. Based on calculation of the
amount of water between joints and mea-
surement of the effluent, six 125-mL
samples are obtained from each loop as
near to a joint as possible. The average of
six samples at each pH for each time
period of standing water is reflected in
Table 8.
In a 4-wk time standing period, the
average lead leached into water was 1900
M-g/L at 5.0 pH. Note in Table 8 that in all
time periods, except for 1-hr sample, the
lead leaching decreased with an increase
of pH. Also, in each pH range, nearly all
values of lead leaching increased with time.
The highest lead values in the three
substitute solder loops were also deter-
mined. In the silver/copper solder loop, the
highest lead in 23 loop samples was 15
u.g/L lead at 5.3 pH in 4 hr. In the tin/
copper solder loop, the three highest leads
in 25 loop samples were (1) 42 ng/L lead
at 7.4 pH in 4 hr; (2) 20.5 ^ig/L lead at 5.2
pH in 12 hr, and (3) 18.3 u.g/L lead at 5.1
pH in 8 hr. In the tin/antimony solder loop,
the three highest leads in 27 loop samples
were (1) 57.5 u,g/L lead at 5.3 pH in 4 hr;
(2) 17.3 u.g/L lead at 5.1 pH in 4 wk, and
(3) 11 u.g/L lead at 5.1 pH in 8 hr.
The tin/antimony solder contained 6.0%
antimony, 86.2% tin and 0.1% lead. Anti-
mony leaching studies on this solder were
performed at four pH values (5.3, 6.3, 7.4,
and 8.5) at various time intervals. Six
samples were used at each test. Most of
the values (88 of 96) were below the de-
tectable limit of 4 )ig/L antimony for leach-
ing time of up to 24 hr. Eight of 12 samples
had antimony values between 4 and 10
(ig/L for a detention time of 4 days at pH
values of 7.4 and 8.5. At a pH of 8.5 and a
detention time of 4 days, 5 of 6 samples
had antimony values in the 8 to 11 jig/L
range. In a 4-wk period, only 8 of 24
samples had antimony values less than 4
u.g/L. The highest value of 68 u.g/L was
obtained at a pH of 7.4.
The tin/copper solder used in con-
structing the tin/copper bop contained 3.0%
copper, 94.7% tin, and 0.04% lead. Copper
leaching studies were performed on each
of the loops at various standing times
ranging from 4 to 24 hr. The copper
leaching increased only slightly (<50%) with
time, but increased greatly (factor of 10 to
40) when pH was reduced to less than 7.0.
Six water samples were taken for copper
analysis in each tin/copper solder loop test.
Only one sample was tested for copper in
each of the other three loop tests. In gen-
eral, the copper leaching was slightly
greater (<50%) in the silver/copper solder
loop than in the tin/copper solder loop,
which is probably explained by the higher
percentage of copper in the silver solder
(88.0%). In general, copper leaching in the
tin/lead solder loop and the tin/antimony
solder loop was only slightly (<50%) less
than that in the tin/copper solder loop. It
appeared that little or no copper leached
from the copper solder, and nearly all the
copper leaching was from the copper pip-
ing itself.
The silver/copper solder contained 6.9%
silver and 88.0% copper. Twenty-three
water samples were collected on the silver/
copper solder loop, included four ranges of
pH (5.3, 6.3, 7.4 and 8.5) and nine time
intervals of standing water (4 hr through 4
wk). In 138 samples, only two showed
silver above the detectable limit of 2 \ig/L.
Two of six samples at pH 8.5 in the 12 hr
standing water test indicated 104 p.g/L and
3.1 ng/L of silver.
Conclusions and
Recommendations
Several field and laboratory studies
have shown the effect of pH on lead solu-
bility and corrosion rates from lead pipes
and from lead solders. This project was
-------
Table 2. Water Quality Parameters and Values of Tested Waters
Parameter Mean Average
Range
Private Wells (pH 5.6 - 6.8)
pH (units)
Alkalinity (mg/L as CaCO^
Langelier Saturation Index
Total Dissolved Solids
Chlorides (mg/L)
Sulfates (mg/L)
South Huntington (pH 6.4 & less)
pH (units)
Alkalinity (mg/L as CaCOJ
Langelier Saturation Index
Total Dissolved Solids
Chlorides (mg/L)
Sulfates (mg/L)
South Huntington (pH 7.0-7.4)
pH (units)
Alkalinity (mg/L as CaCOJ
Langelier Saturation Index
Total Dissolved Solids
Chlorides (mg/L)
Sulfates (mg/L)
6.2
18
-3
137.5
16.5
22
5.8
7
-4.3
46.5
3
<2
7.1
27
-2.4
71
7
3
6.2
16.4
-3.2
144.4
15.5
28.9
5.9
8
-4.2
53.8
3.3
0.8
7.1
27.7
-2.4
72.4
8.1
4.7
5.6-6.8
6-33
(-4. 4) -(-2. 1)
35-415
4-32
3-101
5. 1-6.4
1-25
(-5)-(3)
22-131
<2-15
<2-12
7.0-7.4
0-51
(-2.1)(-1.6)
6-168
4-27
<2-27
South Huntington (pH 8.04 & greater)
pH (units)
Alkalinity (mg/L as CaCOJ
Langelier Saturation Index
Total Dissolved Solids
Chlorides (mg/L)
Sulfates (mg/L)
8.5
28
-1.0
154.5
8.5
3
8.5
29.5
-1.0
130.2
9.6
5.0
8.0-9. 1
5-46
(-1 .9)-(-0.3)
8-229
3-21
1-17
Table 3. Percentage of Test Homes Having Water with Greater Than 50 \ig/L and 20 \ig/L Lead at
Low pH (6.4 and less) in 9 Age Categories
Lead
Level,
WL
>50
>20
Age of
Plumbing,
yr
0-1
1-2
2-3
3-4
4-5
6-7
9-10
14-17
20 & older
0-1
1-2
2-3
3-4
4-5
6-7
9-10
14-17
20 & older
Percentaoe of Homes
First
Draw
100
57
71
86
57
44
43
57
43
100
100
86
100
57
78
71
71
86
10
Sec
100
57
43
71
0
22
14
14
29
100
71
71
86
28
44
28
14
29
20
Sec
100
29
43
29
14
22
0
0
0
100
86
57
85
43
33
14
14
28
30
Sec
86
29
29
14
0
0
0
0
0
100
71
57
71
42
33
14
14
0
45
Sec
67
14
14
43
0
0
0
0
0
100
57
43
71
43
11
14
14
14
60
Sec
71
29
29
29
0
0
0
0
0
86
29
43
71
14
11
14
14
0
90
Sec
71
29
29
29
0
0
0
0
0
86
43
43
29
0
11
10
14
14
120
Sec
71
14
29
0
0
0
0
0
0
86
29
29
43
0
0
0
14
0
unique in that the pH of the water delivered
to the customers could be adjusted and
regulated so that the effect of pH on lead
leaching could be measured. Furthermore,
the homes used as test sites were chosen
to cover a range of ages from new homes
to those over 20 yr old. As expected, lead
leaching increased with a decrease in pH
of the water and generally decreased with
an increase in age of the home. The data
obtained from this project clearly points
out the role of sampling techniques and
the need to draw sequential samples in
order to locate the source of lead. High
lead values with first draw samples fol-
lowed by a sudden decrease in lead con-
centrations indicates that the faucet may
be the major source of lead.
Since tin/lead solder was the source of
lead in the drinking water, the pipe loop
studies were aimed at ascertaining the
alternative solders that might be used. The
data obtained indicated that the alternative
solders could be safely used. With a pH
adjustment above 7, the metal components
of the solders were below the MCL.
The water quality parameter that was
deliberately changed was limited to pH
adjustment with the addition of sodium
hydroxide. Therefore, increasing pH may
not be sufficient to reduce lead levels to an
acceptable value. Other sources with other
water quality parameter values may need
other additives, such as inhibitors or other
chemicals, for alkalinity adjustments. The
results of this project indicate the need to
monitor carefully, and the sampling tech-
niques needed to find the source of the
lead.
The full report was submitted in fulfill-
ment of Cooperative Agreement
CR810958-01-1 by South Huntington Wa-
ter District under subcontract to H2M Group
under the sponsorship of the U.S. Environ-
mental Protection Agency.
-------
Table 4. Percentage of Test Homes Having Water With Greater Than 50 \ig/L and 20 \ig/L
Lead at Medium pH (7.0-7.4) in 9 Age Categories
Lead
Level,
]&L
>50
>20
Age of
Plumbing,
yr
0-1
1-2
2-3
3-4
4-5
6-7
9-10
14-17
20 & older
0-1
1-2
2-3
3-4
4-5
6-7
9-10
14-17
20 & older
Percentaae of Homes
First
Draw
90
50
10
20
20
0
10
20
10
100
80
30
50
30
10
20
40
20
10
Sec
60
30
20
10
10
0
0
10
0
90
60
20
20
10
0
0
20
0
20
Sec
40
10
10
10
0
0
0
0
0
90
40
10
20
10
0
0
20
0
30
Sec
20
0
10
20
0
0
0
0
0
60
10
10
30
0
0
0
10
0
45
Sec
0
0
0
10
10
0
0
0
0
30
20
10
20
10
0
0
0
10
60
Sec
0
0
0
20
0
0
0
0
0
20
0
0
30
0
0
0
0
0
90
Sec
10
0
0
20
0
0
0
0
0
10
10
0
30
0
0
0
0
0
120
Sec
0
0
0
0
0
0
0
0
0
10
0
0
20
0
0
0
0
0
Table 5.
Percentage of Test Homes Having Water With Greater Than SOpg/L and 20 pg/L
Lead at High pH (8.0 and greater) in 9 Age Categories
Lead
Level
W/L
>50
>20
Age of
Plumbing,
yr
0-1
1-2
2-3
3-4
4-5
6-7
9-10
14-17
20 & older
0-1
1-2
2-3
3-4
4-5
6-7
0-10
14-17
20 & older
Percentaae of Homes
First
Draw
100
22
10
13
20
0
0
33
20
100
67
30
25
30
20
10
33
20
10
Sec
80
11
0
0
0
0
0
11
0
100
22
10
0
0
0
0
22
0
20
Sec
10
11
0
0
0
0
0
11
0
60
11
20
0
0
0
10
11
0
30
Sec
0
11
0
0
0
0
0
10
0
10
11
0
0
0
0
0
11
0
45
Sec
0
11
0
0
0
0
0
0
0
20
11
0
0
0
0
10
0
0
60
Sec
0
0
0
0
0
0
0
0
0
10
11
10
0
0
0
10
0
0
90
Sec
0
11
0
0
0
0
0
0
0
20
11
0
0
0
0
0
0
0
120
Sec
0
0
0
13
0
0
0
0
0
0
11
0
13
0
0
10
0
0
-------
Table 6. Percentage of Test Homes Having Water With Greater Than 20 \ng/L of Lead
Percentage
Age of
Plumbing, yr
0-1
1-5
6-20
yr&
greater
pH
6.8 & less
7.0 - 7.4
8.0 & greater
6.8 & less
7.0 - 7.4
8.0 & greater
6.8 & less
7.0 - 7.4
8.0 & greater
First
Draw
100
100
100
93
48
38
77
23
21
10
Sec
100
90
100
71
28
8
30
5
5
20
Sec
100
90
60
64
20
8
23
5
5
30
100
60
10
61
13
3
16
3
3
45
Sec
100
30
20
53
15
2
13
2
2
60
Sec
86
20
10
46
8
5
10
0
3
90
86
10
20
32
10
3
10
0
0
120
Sec
86
10
0
25
5
5
3
0
3
Table 7. Average Lead Content and Major Component of Solders
Solder Lead Tin Antimony Silver
Copper
Tin/lead
Tin/antimony
Tin/copper
Silver/copper
60.8
0.10
0.04
<0.002
86.2 6.0
94.7
— —
— —
— 3.0
6.9 88.0
Table 8. Average Lead Leached Into Water From Tin/Lead Solders in Pipe Loop Studies at
Various pHs and Time Intervals
Lead Concentration, \ng/L
Standing
water, hr
24
12
8
4
2
1
pH
5.2
983
933
900
752
NT
NT
pH
6.4
322
200
169
140
36
8
pH
7.4
42
28
33
12
22
9
pH
8.6
15
14
7
8
NT
NT
NT = not tested
#U.S.GOVERNMB*T PRINTING OFFICE: 1991/548-028/20165
-------
Norman E. Murrell is with HM Group, Melville, NY 11747-5076.
Marvin C. Gardels is the EPA Project Officer (see below).
The complete report, entitled "Impact of Lead and Other Metallic Solders on Water
Quality," (Order No. PB91-125 724/AS; Cost: $17.00, subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-90/056
------- |