United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-85/042 Sept. 1985
Project Summary
Controlling Asbestos Loss from
Asbestos-Cement Pipe in
Aggressive Waters
Carol H. Tate, Brian L. Ramaley,
John J. Vasconcelos, and Bruce M. Chow
A project was undertaken to evaluate
measures for controlling the loss of
asbestos fibers from asbestos-cement
(A/C) water distribution pipe under
aggressive water conditions. The pro-
ject was divided into two phases: (1)
data collection and pilot tests of alter-
native control strategies, and (2) field
testing of the most effective control
strategy.
During Phase 1, water quality data
were analyzed for the existing distribu-
tion system of the City of Bellevue,
Washington, which receives its drink-
ing water from Seattle Water Depart-
ment's Tolt and Cedar River systems.
Samples were collected at monthly
intervals for 1 year from both sources
before and after exposure to A/C pipe.
Both sources were shown to be aggres-
sive to A/C pipe, as evidenced by
higher asbestos fiber counts, pH, cal-
cium and alkalinity after exposure to
the pipe. The Tolt supply was the more
agressive of the two sources and was
therefore studied further.
The pilot tests in Phase 1 evaluated
eight alternative control strategies for
curtailing pipe deterioration, including
pH adjustment and addition of zinc
chloride, sodium metasilicate, or ferric
chloride. The zinc chloride/pH adjust-
ment strategy performed best and was
chosen for the Phase 2 field test.
Phase 1 testing also involved the
selection of quantitative measures to
determine the hardness of A/C pipe
before and after exposure to aggressive
water, both in the pilot tests and in the
distribution system. The Shore D and
Rockwell L hardness tests were found
useful in quantifying pipe hardness.
Selection of control measures was
complicated by the fact that the Seattle
Water Department had recently com-
pleted a corrosion study and was plan-
ning to institute its own corrosion
control program of pH adjustment for
both the Tolt and Cedar supplies. The
pilot tests, therefore, assumed the pro-
posed Seattle Corrosion Control Pro-
gram as a baseline.
In Phase 2, a test and a control loop
were established in the distribution sys-
tem, with samples collected before and
after exposure to A/C pipe at monthly
intervals for 1 year. The test strategy
was to add 0.6 mg/L zinc chloride at a
point in Clyde Hill, an isolated pressure
zone within Bellevue. The control sec-
tion was in the northeastern portion of
the Bellevue 520 zone. Both locations
received water from the Tolt system.
Immediately before the Phase 2 field
test, the Seattle Water Department
began its full-scale corrosion control
program, so both sections received
water that had been adjusted upward in
pH and alkalinity, complicating the abil-
ity to separate the effects of zinc from
the effects of pH and alkalinity
adjustment.
The field test in Phase 2 did not show
conclusively whether the zinc chloride
addition effectively prevented pipe
deterioration and fiber loss. Results
over time from the test section with
zinc chloride and the control section
were similar, suggesting that the alka-
linity and pH increases in effect at the
time of the field test may have acted to
protect the pipe from deterioration.
Further testing of 6 to 12 months
appears to be necessary to reach a
-------
firmer conclusion about the effect of
the zinc addition.
This Project Summary was deve-
loped by EPA's Water Engineering
Research Laboratory, Cincinnati, OH,
to announce key findings of the
research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
The City of Bellevue, Washington,
located near the Metropolitan Seattle
area, began using asbestos cement (A/C)
pipe for its water distribution system in
the 1940's. A/C pipe makes up approxi-
mately 90 percent, or about 483 km (300
miles), of the city's distribution system.
Bellevue receives its water from the City
of Seattle. Because of its location, Bel-
levue generally receives primarily Tolt
River water in the northern portion of the
city and primarily Cedar water in the
south.
Both water supplies are low in mineral
content, with total dissolved solids (IDS)
values typically lower than 30 mg/L, and
alkalinity values of about 16 mg/Lforthe
Cedar River supply and 5 mg/L for the
Tolt supply. Cedar River pH averages
about 7.4, and Tolt River pH averages
about 5.7. As a consequence of this low
mineral content and pH, the Langelier
Index is as low as -5 for Tolt River water
and -2 for Cedar River water.
This study was instituted to evaluate
different methods of controlling asbestos
fiber loss. Both pilot plant and field tests
were conducted. Phase 1 involved the
study of a distribution system and pilot
plant testing, and Phase 2 consisted of a
field test to evaluate the most promising
control strategy found in the pilot test.
Between Phases 1 and 2 of the Bel-
levue study, the City of Seattle imple-
mented a corrosion control program
consisting of pH adjustment for Tolt and
Cedar waters and alkalinity adjustment
for Tolt water.
Methods
Methods of Analysis
Whenever possible, standard methods
of analysis were used. The interim
method (counting asbestos fibers under a
transmission electron microscope) was
used to determine the asbestos fiber con-
centrations in water. The detection limits
are variable and dependonthe amount of
total paniculate matter in the sample as
well as the contamination level in the
laboratory environment. Under favorable
circumstances, detection limits of 0.01
million fibers per liter (MFL) can be
obtained.
Samp/ing Methods
Asbestos samples were taken in clean,
1 -L polyethylene bottles. Except for two
locations, the sampling sites were set up
for continuous flow to assure representa-
tive samples. The exceptions were two
sites at the inlet to the Clyde Hill system
in Phase 2 of this study. In those instan-
ces, the port was opened and allowed to
run before sampling. The sample bottles
were filled about one quarter full and
rinsed with the sample water. This rins-
ing step was repeated before a sample
was taken. Finally, the bottle was filled,
allowing 2 in. of air space in the bottle for
shaking. No preservatives were used.
Hardness Tests
Hardness tests borrowed from the
material science field were used to pro-
vide reproducible and objective mea-
sures of the conditions of the inner
surfaces of the A/C pipe. Hardness was
measured as the resistance to indenta-
tion by a hard ball or cone under a given
static load. Since the release of asbestos
fibers and the general deterioration of
A/C pipe in water is related to the deteri-
oration of the cement matrix, the hard-
ness or spongmess of the remaining A/C
pipe material should be a measure of its
condition. Two tests were found suitable
for use on AC pipe. The first was the
Shore D test, a member of a class of
durometer tests normally used for hard
rubbers or plastics. The second, the Rock-
well L test, is generally used on harder
materials such as metals. The Shore D
tests consist of a calibrated spring that
forces a sharp point into the material. The
Shore D range goes from 100 (which is
the hardest) to 0 (which is the softest) and
corresponds to a 0.25-cm (0.1-in.) maxi-
mum indentation. The Rockwell L test is
one of a series of Rockwell tests that use
a steel ball or a diamond cone to pene-
trate the material. For the Rockwell Ltest,
a minor load of 10kg is first used to set an
initial indentation, after which an addi-
tional major load of 60 kg is applied to
make the final indentation. A 0.64-cm
(0.25-in.) steel ball is used in this test. As
with the Shore D test, the range in hard-
ness is from 100 (indicating a very hard
material) to 0 (indicating a very soft mate-
rial). The Shore D and Rockwell L test
results do not necessarily correspond or
correlate with each other. In both tests,
three separate readings are taken on a
single sample and then averaged into a
single result for that sample.
To test the appropriateness of the
Shore D and Rockwell L hardness tests,
coupons of A/C pipe measuring 5 by 5 cm
(2 by 2in.) were analyzed. The results of
these tests are shown in Table 1. Both
test procedures yielded the same relative
order, from softest to hardest, for all three
pipe samples. In addition, the spread of
values obtained for each pipe section was
relatively narrow. Thus it could be
expected that results may be reproduci-
ble and show good relative hardness
results from one sample to the next.
One other concern that needed to be
satisfied was the effect of moisture on
the hardness tests for the A/C test cou-
pons. Hardness tests were run on A/C
pipe coupons after removal from water,
after drying for 24 hr, 36 hr, 4 days, and 8
days, and after 8 hours of drying plus 48
h'r in an oven at 100°F. Test results indi-
cated that the hardness changed only 5 to
10 percent despite the variation of drying
times and procedures. Therefore it was
concluded that either air-dried or oven-
dried A/C pipe coupons could be sub-
jected to hardness testing.
Scanning electron microscope anal-
yses were also applied to the A/C pipe
coupons to determine (1) the surface
composition of the A/C pipe, and (2) the
degree to which calcium had leached
from the pipe matrix.
Phase 1A: Characterization of
the Distribution System
In anticipation of the field test using a
corrosion control strategy from the pilot
test, it was necessary to characterize the
Bellevue distribution system to (1) docu-
ment the changes in the water quality
throughout the distribution system, and
(2) assess the A/C pipe condition after 30
to 40 years of exposure to both Tolt and
Cedar River waters. Samples taken in
this phase of the study were taken before
the Seattle Corrosion Control Program
went into effect.
The most notable aspects of Tolt water
are its low pH (generally averaging about
5.7) and its low mineral content (with
calcium at 7.4 mg/L, alkalinity at 5.1
mg/L, silica at 5.5 mg/L, and an overall
TDS of about 14 mg/L). Changes in water
quality conditions generally supporting
the deterioration of A/C pipe and found
to be significant at the 5 percent level
using T-test analysis were chrysotile
concentrations, alkalinity, Langelier
Index, pH, TDS, and silica. Also, a notable
decrease was found in the Tolt water zinc
level, which possibly indicates protective
action on A/C pipe.
-------
Table 1. Initial Hardness Test Results for A/C Coupons (3/25 81)*
Sample Number
A-1
A-2
A-3
A -4
Average
Std. Dev.
B-1
B-2
B-3
B-4
Average
Std. Dev.
C-1
C-2
C-3
C-4
Average
Std. Dev.
Description
6" A/C Pipe
9200 NE 34th
6" A/C Pipe
Unknown
Location
8" A/C Pipe
New, Uninstalled
Pipe
Shore "D '
Hardness
67
65
66
64
65.5
1.29
68
74
67
73
70.5
3.51
79
81
82
78
80.0
1.83
Rockwell "L"
Hardness Scale
7
10
5
14
9.0
3.92
64
60
65
56
61.5
4.11
99
100
98
98
98.7
0.96
'Tests performed by Northwest Laboratories of Seattle, Inc.
The mineral content of Cedar River
water is generally higher but neverthe-
less low compared with that of other
water supplies. IDS levels were 35
mg/L, with calcium at 6.99 mg/L, alka-
linity at 16.5 mg/L, silica at 9.74 mg/L,
and a Langelier Index ranging from -0.53
to -3.14. Again, statistically significant
increases were found in the chrysotile
concentration, Langelier Index, alkalin-
ity, pH, and calcium and silica concentra-
tions. These increases support the
conclusion that Cedar River water is also
aggressive with respect to A/C pipe. The
decrease in zinc concentration in the
Cedar portion of the system was not
found to be statistically significant. The
differences found between the Toll and
Cedar River water supplies were consist-
ent throughout the year of monitoring.
Water entering the Seattle and Bellevue
distribution systems from the Tolt River
was higher in chrysotile concentration
and lower in pH, alkalinity, calcium, and
silica. The Tolt water supply was also
more negative in Langelier Index.
Samples of A/C pipe were also taken
for conducting the Shore D and the Rock-
well L hardness tests. The results for
these tests are summarized in Table 2.
Samples designated 300 and 400 were
new, unused A/C pipe and served as a
reference point for used A/C pipe. Sam-
ples designated 500 through 510 were
taken from the distribution system. The
results indicate that, on the average, the
Shore D hardness changed approxi-
mately 0.5 point per year, whereas the
Rockwell hardness changed approxi-
mately 2 points per year. All pipes
showed evidence of softening through-
out their 30- to 40-year service periods.
Phase 1 B: Recirculation
Experiments
Six corrosion control strategies were
tested on a pilot scale in this part of Phase
1. The tests lasted 48 weeks and were
conducted in eight separate 378-L(100
gal) systems. Two of the systems were
used as controls A/C coupons were
placed in special holders and placed in
line with the recirculation loop. Control
strategies and results are presented in
Table 3.
All tanks showed an increase in
chrysotile fibers as would be expected,
but the zinc strategies showed the best
inhibition of fiber release.
All coupons showed some signs of sof-
tening. Although differences in hardness
were small, the zinc strategies appeared
to be the; best for preventing
deterioration.
Calcium loss analyses were conducted
by the U.S Environmental Protection
Agency (EPA) using a scanning electron
microscope with an energy-dispersive X-
ray (EDX) device. This analysis measured
the depth to which calcium had been
leached from the cement matrix of the
pipe; results ranged from undetected lev-
els to 0.3 mm The zinc strategies showed
the least amount of calcium leaching.
Based on all of the results put together,
zinc was concluded to be the best corro-
sion inhibition strategy, so the field test
added zinc chloride to the water supply.
Phase 2: Field Test
The field tests of zinc chloride began
immediately after the startup period
ended for the Seattle corrosion control
program. The field test site was chosen in
an area receiving exclusively Tolt River
water. After the startup of the Seattle
corrosion control program, lime addition
for the Tolt supply was set to maintain a
pH of 8.2, and soda ash addition was set
to add 7 mg/Lof alkalinity tothatexisting
in the Tolt water.
Site selection involved sixbasic criteria
for the actual test site:
1. The site must receive Tolt water
exclusively.
2. The area must be isolated to avoid
affecting surrounding areas.
3. The area must be small enough to
minimize chemical costs.
4. The test area must provide a deten-
tion time of approximately 15 to 20 hr
between the chemical addition point
and the final sampling point to match
the detention times used in Phase 1 A.
5. A control area with the same water
supply and a similar detention time
must be available.
6. The site must have a structure availa-
ble for housing the chemical feed sys-
tem and must also have a flow
metering system that can be used to
pace the chemical feed into the water
supply lines.
The test area chosen was the Clyde Hill
zone directly northwest of the Bellevue
Civic Center. Sampling points on the
Clyde Hill distribution network were then
assigned (Figure 1). A sampling site just
upstream of the chemical addition point
was labeled CH1, and a point near the
end of the system and representing 16 to
18 hr of detention time was labeled CH2.
A sampling point just after the chemical
addition, labeled CH1A, was used to
verify the zinc dose. Two dead-end points
on the system, labeled CHS and CH4,
were used to detect any buildup of panic-
ulate zinc. Finally, two sewage sampling
points that drain the Clyde Hill system
were designated S1 and S2. These two
points were used to estimate the amount
of zinc leaving the system.
The control area chosen was the same
as that used in Phase 1A for the Tolt
water and is located directly east of the
Clyde Hill area. The original sampling
location designations, D3 and D4, were
kept during the field test. The detention
time in the control system was approxi-
mately 15 to 25 hr under average
conditions.
Water quality sampling was scheduled
on a monthly basis for asbestos fibers
-------
Table 2. Hardness Testing Results for Coupons Removed from the Distribution System
Sample
Number
300
400
500
501
502
503
504
505
506
507
508
509
510
Location
—
....
16240 SE 9th
NE 2nd at Overtake Dr.
1 66th at DW 35th
3440 NE 78th
8015 NE 28th
4315 SE 134th
92 Ave NE at NE 34th
91stNE 10
Overtake Dr. at Upland
2515-86 Ave NE
31 04-1 24th SE
Shore "D" /
Hardness H
89
91
57
55
68
66
69
76
77
70
68
72
79
Rockwell "L"
Hardness Scale Remarks
108 new pipe (unused)
104 new pipe (unused)
37 rust-red deposits, smooth interior
51 installed 1948. reddish-brown, rough
39 some brown deposits, smooth interior
45 some red deposits, smooth interior
41 installed 1943, dark brown
65 light tan, some roughness
-7 Of brown, smooth
22 dark brown
61 very dark brown, smooth
64 rough, white interior
85 rough, white interior
* All analyses performed by Northwest Laboratories of Seattle.
t Tapered end of pipe interfered with test.
All results are average of 3 readings.
Table 3. Selected Water Quality and Hardness Test Results for Recirculation Tank Corrosion Control Experiments
Water Quality Results Hardness Results
Tank Conditions
1 Cedar Control
2 Toft Control
3 Tolt; Seattle Corrosion
Control Program (SCCP);
pH = 8.0
4 Tolt; SCCP; Add'l lime;
pH = 9.0
5 Tolt; SCCP; 0.3 mg/L In;
pH = 8.5
6 Tolt; SCCP; 0.6 mg/L Zn;
pH = 8.0
7 Tolt; SCCP; 12. 7 mg/L Sio2;
pH = 8.0
8 Tolt; SCCP; 0.2 mg/L Fe;
pH = 8.0
«• All 1 t • i
Exposure
Time (Wks)
0
12
24
36
48
0
12
24
36
48
0
48
48
0
48
48
0
48
48
0
48
48
0
48
48
0
48
48
Chrysotile
Concentration
MFL
5.7
50,9
--
60.9
24.6
54.5
--
69.3
10.7
82
17.3
166
9.7
23.7
8.4
34.9
...
12.5
39.7
3.1
170
-
Calcium
Increase
mg/L
-.
--
--
4
__
-.
--
--
4
._
2
--
__
2
--
_.
1.5
--
..
1.5
--
--
2
--
..
2
--
Silica
Increase
mg/L
..
--
--
4
..
.-
..
4
2
-
..
2
-.
;
--
..
7
--
-.
/
--
7
-
Coupon
No.
T1-1
T1-2
T1-3
T1-4
72-7
72-2
72-3
72-4
73-7
73-2
74-1
T4-2
T5-1
75-2
T6-1
T6-2
..
77-7
77-2
T8-1
78-2
Shore "D"
88
88
80
84
88
88
81
87
85
82
85
85
87
86
86
85
„
83
82
82
82
Rockwell "L"
102
97
98
93
101
100
98
91
89
93
97
92
92
95
95
98
90
90
91
92
-------
Toll Supply
Scale
305m
1000ft
Figure 1. Clyde Hill 465 Zone pipe network.
and 20 other water quality parameters
especially those associated with the
deterioration of A/C pipes, such as cal-
cium and silica. In addition, particulate
and total zinc samples were taken at the
deadends (CHS and CH4) on a quarterly
basis. The zinc chloride dose was chosen
to be 0.6 mg/L as zinc. The recirculation
tests of Phase 1B showed that the zinc
solubility at pH 8 was nearly the same as
that at pH 8.5—that is, approximately 0.1
mg/L as zinc. The goal of adding zinc at a
concentration of 0.6 mg/L was to exceed
the soluble amount and precipitate zinc
onto the A/C pipes to form a protective
coating. Another concern was to main-
tain the zinc concentrations throughout
the test area, a procedure very much
analogous to maintaining a chlorine
residual in the distribution system.
Zinc chloride was added to the distribu-
tion system through a metering pump
that was fed by a 65-percent zinc chloride
stock solution A special control system
paced the metering pump speed with the
water flows into the Clyde Hill system.
In addition to the chemical feed sys-
tem, 0.9-m (3 ft) lengths of A/C pipe sec-
tions were installed at locations CH1A,
CH2, D3, and D4. Mortar-lined A/C pipe
sections of the same length were
installed at locations CH1 A, CH2, and D3.
All of these test sections were placed
directly in-line (that is, no special side
loops were created). The purpose for
these special sections of pipe was to
remove them at the end of the study and
test them for hardness.
Test results showed that in the first few
months of the field tests fewer asbestos
fibers were released from the zinc chlo-
ride test section than from the control.
However, later behavior of the control
section (D3 to D4) indicates that the Seat-
tle corrosion control program maybe pro-
viding some protection for the A/C pipes.
This effect can be seen in the asbestos
results some 7 months into the field test.
Because a reduction in asbestos fiber
counts occurred in both the control and
test sections of the field test, the affect of
the zinc chloride treatment is uncertain.
The control area experienced conditions
similar to those in the recirculation tests
of Tanks 3 and 4. Both of these tanks
experienced a reduction in calcium and
silica pickup relative to the untreated
control. Thus it may be reasonable to
assume that the Seattle corrosion control
program is protecting the A/C pipe.
After 12 months of field testing, the
short sections of A/C pipe and mortar-
lined A/C pipe were removed. Coupons
were cut from these pipes and subjected
to the calcium loss analysis and physical
hardness testing. The calcium loss analy-
sis was conducted by EPA as in Phase 1B
of this study. With a precision of approxi-
mately 0.1 mm, no appreciable calcium
loss could be detected on either the cou-
pons subjected to zinc chloride or the
coupons in the control area. In contrast,
the recirculation tests of Phase 18
showed no appreciable loss of calcium
only in the zinc chloride addition tanks
(Tanks 5 and 6). The range of calcium loss
in the other tanks was between 0.2 and
0.3 mm. These results further suggest
that the water quality changes resulting
from the Seattle corrosion control pro-
gram may be protecting the A/C pipe by
virtue of the increase in the Langelier
Index.
Hardness testing using the Shore D
and Rockwell L tests on the pipe sections
removed from the test and control areas
failed to produce any differences
between them.
Another question posed by this project
was whether or not the added zinc was
-------
deposited inside the Clyde Hill pipe net-
work. Zinc concentration at the end of the
network was approximately 50 percent of
the original dose, which indicates some
accumulation in the system.
Evidence exists that both precipitation
and deposition were occurring in the
Clyde Hill network, but the actual propor-
tion of zinc going to one or the other pro-
cess could not be established. Analysis
for total and soluble zinc at the deadends
of the system (CH3 and CH4) indicated
that particulatezinc wasformingatthese
locations. This result indicates that if zinc
is to be added to the Bellevue system,
flushing of deadends would be necessary
at various intervals. Evidence that zinc
may form a coating on A/C pipe comes
from X-ray analysis that detected zinc on
the surfaces of the A/C pipe sections
removed from the field test sites. Zinc
deposition was also evident on the
mortar-lined A/C pipe sections.
A brief cost comparison was conducted
to gain perspective on how zinc chloride
treatment compares with other options
available to the City of Bellevue. The capi-
tal cost estimate included eight separate
chemical feed stations determined on the
simplifying assumption that Bellevue
could be conveniently divided up as such.
Other items included were buildings to
house the equipment, labor to build it,
water meters, and metering pumps. The
buildings were assumed to be built on
land owned by the City of Bellevue.
Annual costs were divided into chemical
costs for zinc chloride (approximately
$12.50/100 Ib) and operating and main-
tenance costs, which included labor,
power, and replacement parts. Convert-
ing the annual costs to an equivalent
present value gives a total value of nearly
$1 million.
Pipe replacement and pipe relining
work were the only alternatives to chemi-
cal treatment considered, since they
represent the conventional ways of deal-
ing with pipe deterioration problems.
Replacing the A/C pipe with steel or duc-
tile iron pipe costs similar amounts, each
totaling about $35.6 million. Both steel
and ductile iron pipe were assumed to be
mortar-lined and mortar-coated.
Replacement with PVC Class 150 pipe
costs approximately 10 percent less than
steel or ductile iron, but PVC pipe is only
available in diameters up to 30 cm (12
in.). For larger diameters, steel pipe was
used. All replacement costs assumed (6-
ft) cover and no allowance for service
connections.
Relining consists of scraping the inside
surface of existing A/C pipe and then
coating it with a mortar lining. Mortar
lining can be accomplished in place on
pipes having diameters of 10 cm (4 in.)
and larger. The total cost of relining is
nearly $20 million, or approximately 60
percent of the cost of replacing the A/C
pipe.
Conclusions
1. Monitoring presents strong evi-
dence that portions of the A/C pipe
matrix were dissolving into the
supply water. This condition was
indicated by increased water con-
centrations of components most
associated with pipe dissolution:
calcium, silica, chrysotile fibers, pH,
and alkalinity. Water from the Tolt
supply (before alkalinity and pH con-
trol was initiated) was more aggres-
sive toward the pipe matrix than
was the Cedar supply.
2. Although a natural background of
chrysotile fibers exists in the water
supply, monitoring results and pilot
studies indicated that the A/C pipes
do release these fibers into the
water.
3. Hardness tests such as the Shore D
and the Rockwell L are useful for
determining the condition of A/C
pipe; however, the natural variabil-
ity in the samples and method
results suggests that time periods
greater than 1 year are required for
determining statistically whether
any changes in hardness have
occurred The Shore D test can be
conducted in the field with a small,
handheld durometer.
4. Older A/C pipes removed from the
Bellevue network show softening as
measured by the Shore D and Rock-
well L. tests. These tests might be
used to determine a priority system
for a planned replacement program.
5. Though zinc chloride was found to
be effective in controlling A/C pipe
corrosion in the pilot test, it could
not be determined whether the zinc
chloride was effective under field
test conditions. This uncertainty
may have been the result of the
alkalinity and pH control recently
initiated by the Seattle Water
Department for the source water
supply.
6. The alkalinity and pH control may be
protecting the A/C pipe or at least
slowing down the deterioration. Evi-
dence of this is seen in the chryso-
tile data for the field test. Both the
control area and the test area (with
zinc chloride added) behaved the
same, showing a decrease in fiber
pickup over the course of the field
test.
7. Evidence from the field test sug-
gests that the zinc accumulated in
the test area as both particulate and
deposited zinc.
The full report was submitted in fulfill-
ment of Cooperative Agreement No.
CR807789010 by James M. Montgo-
mery Consulting Engineers, Inc. under
the sponsorship of the U.S. Environmen-
tal Protection Agency.
. S. GOVERNMENT PRINTING OFFICE: 1985/559-111/20682
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CarolH. Tate, Brian L. Ramaley, JohnJ. Vasconcelos, and Bruce M. Chow are with
James M. Montgomery Consulting Engineers, Inc., Pasadena, CA 91101.
Gary S. Logsdon is the EPA Project Officer (see below).
The complete report, entitled "Controlling Asbestos Loss from Asbestos-Cement
Pipe in Aggressive Waters," (Order No. PB 85-191 690/AS; Cost: $20.50,
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:
Water Engineering Research 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/S2-85/042
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