U.S. Department of the Interior
U.S. Geological Survey
Volatile Organic Compounds Detected in
Vapor-Diffusion Samplers Placed in
Sediments Along and Near the Shoreline at
Allen Harbor Landfill and Calf Pasture
Point Davisville, Rhode Island,
March-April 1998
Open-File Report 99-74
Prepared in cooperation with the
U.S. ENVIRONMENTAL PROTECTION AGENCY
4»EPA
USGS
science for a changing world
-------
U.S. Department of the Interior
U.S. Geological Survey
Volatile Organic Compounds Detected in
Vapor-Diffusion Samplers Placed in
Sediments Along and Near the Shoreline at
Allen Harbor Landfill and Calf Pasture
Point, Davisville, Rhode Island,
March-April 1998
By FOREST P. LYFORD, JOHN D. KLIEVER, U.S. Geological Survey, and
SCOTT CLIFFORD, U.S. Environmental Protection Agency
Open-File Report 99-74
Prepared in cooperation with the
U.S. ENVIRONMENTAL PROTECTION AGENCY
Marlborough, Massachusetts
1999
-------
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director
The use of trade or product names in this report is for identification
purposes only and does not constitute endorsement by the
U.S. Geological Survey.
For additional information write to:
Chief, Massachusetts-Rhode Island District
U.S. Geological Survey
Water Resources Division
28 Lord Road, Suite 280
Marlborough, MA 01752
Copies of this report can be purchased from:
U.S. Geological Survey
Information Services
Box 25286
Denver, CO 80225-0286
-------
CONTENTS
Abstract 1
Introduction 2
Study Area 2
Allen Harbor Landfill 2
Calf Pasture Point 3
Study Methods 4
Volatile Organic Compounds Detected in Vapor-Diffusion Samplers 4
Allen Harbor Landfill 5
Calf Pasture Point 5
References 5
FIGURES
1—3. Maps showing:
1. Location of Allen Harbor Landfill and Calf Pasture Point study areas, Davisville,
Rhode Island 6
2. Locations of vapor-diffusion samplers, samplers that detected organic vapors,
and selected monitoring wells, Allen Harbor Landfill 7
3. Locations of vapor-diffusion samplers, samplers that detected organic vapors,
and selected monitoring wells, Calf Pasture Point 8
TABLES
1. Reporting limits for target volatile organic compounds at Allen Harbor Landfill and
Calf Pasture Point, Davisville, Rhode Island, March-April 1998 9
2. Concentrations of volatile organic compounds in vapor-diffusion samplers at
Allen Harbor Landfill, April 1998 9
3. Concentrations of volatile organic compounds in vapor-diffusion samplers at
Calf Pasture Point, April 1998 9
Contents III
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CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATIONS
CONVERSION FACTORS
Multiply By To obtain
feet (ft) 0.3048 meters
inches (in.) 25.40 millimeter
miles (mi) L609 kilometers
VERTICAL DATUM
Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD
of 1929)—a geodetic datum derived from a general adjustment of the first-order level nets of the
United States and Canada, formerly called Sea Level Datum of 1929.
ABBREVIATIONS
mL milliliters
ppb parts per billion
Hg/L micrograms per liter
IV Contents
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Volatile Organic Compounds Detected in
Vapor-Diffusion Samplers Placed in Sediments
Along and Near the Shoreline at Allen Harbor
Landfill and Calf Pasture Point, Davisville,
Rhode Island, March-April 1998
By Forest P. Lyford, John D. Kliever, and Scott Clifford
Abstract
^-Volatile organic compounds are present in
ground water at the Allen Harbor Landfill and the
Calf Pasture Point sites on the former Naval
Construction Battalion Center in Davisville, R.I.
Vapor-diffusion samplers were used at the two
sites during March-April 1998 to identify possible
discharge points for contaminants along the shore
of Allen Harbor and in two wetland areas near the
shore. Results from vapor-diffusion samplers will
be used in conjunction with other site information
to evaluatCrproposed ground-water monitoring
programs.^!
Volatile organic compounds were detected
in 41 of 115 samplers placed along the shoreline at
the Allen Harbor Landfill. Trichloroethylene was
the principal volatile organic compound detected
of eight target compounds. The highest vapor
concentration measured exceeded 300,000 parts
per billion by volume in an area where TCE was
detected in ground water from nearby monitoring
wells. Other chemicals detected in vapor-diffusion
samplers included tetrachloroethylene, toluene,
and benzene. Concentrations of individual volatile
organic compounds were less than 100 parts per
billion by volume in most samplers.
Volatile organic compounds, principally
trichloroethylene, were detected in 7 of 30 sam-
plers placed along the shoreline at Calf Pasture
Point; the highest trichloroethylene concentration
was 1,900 parts per billion by volume. A trace
concentration of tetrachloroethylene was detected
in one of the samplers. One of 24 samplers placed
in two wetland areas near the shore (suspected dis-
charge areas for ground-water containing volatile
organic compounds) detected trichloroethylene at
a vapor concentration of 14 parts per billion by
volume.
Abstract 1
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INTRODUCTION
STUDY AREA
Remedial investigations by the U.S. Navy at the
former Naval Construction Battalion Center in
Davisville, Rhode Island, have detected volatile
organic compounds (VOCs) in ground water at Allen
Harbor Landfill and Calf Pasture Point (EA
Engineering, Science, and Technology, 1996; 1998a).
These two areas are adjacent to Allen Harbor on
Narragansett Bay (fig. 1, in back of report).
Information about discharge areas for ground water
containing VOCs would be useful to the U.S.
Environmental Protection Agency (USEPA), in
conjunction with other site information, to assess
ground-water risks to human health and the
environment and design monitoring programs for
contaminants in ground water. A survey using vapor-
diffusion samplers was requested by USEPA because
prior experience had shown the samplers to be a useful
and inexpensive reconnaissance tool for identifying
discharge points for ground water contaminated by
VOCs (Vroblesky and others, 1996; Lyford and others,
1998; J.R Mulanney, U.S. Geological Survey, oral
commun., 1997). The method had not been used
previously in a coastal setting, so a secondary goal of
the study was to determine if vapor-diffusion samplers
can yield useful information about discharge points for
VOCs in ground water along a coastal shoreline.
Although the data presented in this report indicate that
vapor-diffusion samplers will detect VOCs in
sediments within the zone of tidal fluctuations, the
study did not examine possible effects of tidal cycling
on concentrations of VOCs in the vapor samples, nor
did the study determine actual concentrations of VOCs
in ground water where detected in vapor. Also, the
study did not attempt to identify discharge points for
VOCs in ground water offshore beyond the tidal zone.
The purpose of this report is to present data on
vapor concentrations detected in vapor-diffusion
samplers installed and retrieved during March-April
1998 at the Allen Harbor Landfill and Calf Pasture
Point sites in Davisville, Rhode Island. It is beyond the
scope of this report to explain the distribution and
concentrations of VOCs detected in the samplers. The
vapor samplers were installed and retrieved by USGS
personnel assisted by Christine Williams and William
Brandon, USEPA, and by John Zimmerman, Dynamac,
Inc., a contractor for USEPA. Vapor analyses were
done on-site by Scott Clifford, USEPA, using a
portable gas chromatograph.
The Allen Harbor Landfill and Calf Pasture Point
areas are part of the former Naval Construction
Battalion Center (NCBC) in Davisville, R.I. NCBC
was decommissioned and closed in 1994 (EA
Engineering, Science, and Technology, 1998a).
Investigations of the two areas have identified
contaminants in ground water, principally VOCs. Both
areas are on the shore of Allen Harbor, which is
connected to Narragansett Bay by an entrance channel
(fig. 1). Tidal fluctuations in the harbor are generally
about 5 ft (EA Engineering, Science, and Technology,
1996).
Allen Harbor Landfill
Allen Harbor Landfill occupies most of an area
between Sanford Road and Allen Harbor (fig. 1).
Landfill materials are about 20 ft thick or less.
Geologic materials beneath the landfill and shoreline
include a discontinuous layer of fine to very fine sand,
generally less than 15 ft thick, over a layer of silt that is
20 to 50 ft thick. Peat layers are present in some
locations at the top of the sand layer. The silt layer
overlies till, where present, or bedrock. The depth to
the bottom of the silt layer below sea level ranges from
30 to 50 ft (EA Engineering, Science, and Technology,
1996, figs. 3-3 to 3-5). Ground water in landfill
materials and the sand layer flows from a water-table
mound centered near well MW09-18I (EA
Engineering, Science, and Technology, 1996, fig. 3-10)
eastward to the shore and southward to a mud-flat area
(fig. 2, in back of report). Ground water also flows
westward toward a wetland on the west side of Sanford
Road (fig. 1) during wet seasons (EA Engineering,
Science, and Technology, 1996, chap. 3, p. 10). The
mound is not apparent in water levels measured in
wells screened near the bottom of the silt layer and in
deeper geologic units. Ground-water flow at depth is
predominantly eastward and southeastward toward
Allen Harbor; flow directions change somewhat with
tidal fluctuations (EA Engineering, Science, and
Technology, 1996, figs. 3-10 to 3-18). Vertical
hydraulic gradients are downward in the area of the
water-table mound and upward near the shore (EA
Engineering, Science, and Technology, 1996, figs. 3-3
2 VOCs Detected in Samplers Placed in Sediments Near the Shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, R.I.
-------
to 3-5 and table 3-3). Gradients reverse in some wells
near the shore during high tide, but the reversal is not
consistently observed for all tidal cycles.
The landfill received a variety of wastes
generated at the NCBC from 1946 until 1974, when
disposal activities ceased. A variety of VOCs, including
petroleum-based compounds (benzene, toluene,
ethylbenzene, and the xylenes) and chlorinated
compounds, have been detected in several monitoring
wells placed within the landfill area. The highest
concentrations of VOCs were observed at monitoring
well MW09-20I (380,500 ng/L total chlorinated
VOCs), completed in the sand layer near the shore
(fig. 2) (EA Engineering, Science, and Technology,
1996, figs. 4-18 and 4-20). Compounds detected at
MW09-20I include 1,2-dichloroethylene,
trichloroethylene (TCE), 1,1,2-trichloroethane, and
tetrachlorethane. Other wells where concentrations of
total VOCs exceed 2,000 (xg/L include MW09-07D,
MW09-09D, and MW09-14D (EA Engineering,
Science, and Technology, 1996, fig. 4-22), which are
screened near the bottom of the silt layer. VOCs also
have been detected in water from borings installed in
sediments offshore in the harbor (EA Engineering,
Science, and Technology, 1998b).
The substrate in the tidal zone at the south end of
the landfill consists of fine-grained estuarine deposits
on a tidal mud flat that is exposed during low tide
(fig. 2). Channels carry water through the area during
low tide. A channel along the shore on the south side of
the landfill drains the wetland area west of the landfill
(fig. 1). The substrate in the tidal zone along the east
side of the landfill from the mud-flat area north to a
small jetty (fig. 2) consist mainly of landfill debris and
sand. North of the jetty, the tidal zone substrate
consists mainly of sand. Seeps are apparent in several
locations in the tidal zone during low tide. Along the
east side of the landfill north to the jetty, the surface
slopes steeply into the harbor and the tidal zone is
generally 5 to 10 ft wide. North of the jetty, the slope of
the surface is gentler than to the south and the width of
the tidal zone is generally greater than 10 ft. A small
escarpment stabilized by vegetation marks the high tide
position north of the jetty.
Calf Pasture Point
The stratigraphy at Calf Pasture Point is similar
to that at Allen Harbor Landfill. Fine to very fine sand
overlies a layer of silt, which, in turn, overlies till or
bedrock (EA Engineering, Science, and Technology,
1998a, figs. 3-3 to 3-9). The silt layer is absent along a
north-south-trending till ridge between wells MW07-
26S and MW07-21S (fig. 3, in back of report).
Potentiometric maps indicate that ground water flows
in an arcuate pattern from the area near well MW07-
14D southeastward toward Allen Harbor, southward
toward the entrance channel to Allen Harbor, and
southeastward toward Narragansett Bay (EA
Engineering, Science, and Technology, 1998a, figs. 3-
12 to 3-20). Flow patterns appear to be similar for the
sand, till, and bedrock units. Vertical hydraulic
gradients generally are downward, but near well
MW07-21S the gradient is upward, except during
periods of high tide when the gradient is zero or
downward (EA Engineering, Science, and Technology,
1998a, table 3-3).
The source of VOCs in ground water at Calf
Pasture Point is not well documented but is believed to
be containers of chemicals disposed of in pits in the
general area of well MW07-14D (fig. 3) (EA
Engineering, Science, and Technology, 1998a, fig. 1-2).
VOCs, principally chlorinated compounds, in ground
water are found in fractured crystalline bedrock and
surficial material across an area that extends
southwestward to Allen Harbor, southward toward the
entrance to Allen Harbor, and eastward about one-half
to two-thirds of the distance between Allen Harbor and
Narragansett Bay (EA Engineering, Science, and
Technology, 1998a, figs. 4-17 to 4-19). In general,
highest concentrations of VOCs in ground water are in
wells completed below the silt layer at depths of 30 ft
or more, except in the area of the till ridge where the
silt layer is absent and VOCs are present at shallow
depths of 25 ft or less. Several compounds have been
detected in the VOC plume including vinyl chloride,
1,2-dichloroethene, tetrachloroethylene (PCE), TCE,
and 1,1,2,2-tetrachloroethane.
The substrate in the tidal zone at Calf Pasture
Point consists mainly of fine to medium sand. The
slope of the land surface in the tidal zone is gentle at
the south end in the entrance channel to Allen Harbor
and on the northwest side of the study area. In these
Study Area 3
-------
areas, the tidal zone ranges from 20 to 70 ft. Along the
western shore, slopes are steeper and the width of the
tidal zone is generally less than 10 ft.
STUDY METHODS
Vapor-diffusion samplers were constructed as
described in Vroblesky and others (1996). The
samplers consist of a 40-mL, air-filled glass bottle
wrapped in two polyethylene bags held in place with
cable ties. Duplicate samples for quality control are
constructed by placing two polyethylene-wrapped
bottles in the outer bag. The sampler is attached to a
survey flag for marking and retrieval. When the
sampler is placed in water or saturated sediments
containing VOCs, organic vapors diffuse through the
two layers of polyethylene and equilibrate with air in
the bottle. The time required for equilibration is 24
hours or less in a controlled setting (Vroblesky and
others, 1996). Additional time may be required after
placement of the samplers to allow concentrations of
VOCs in ground water to re-equilibrate in disturbed
materials; a period of 2 weeks is recommended (D.A.
Vroblesky, U.S. Geological Survey, oral commun.
1997). After retrieving the sampler, the outer bag is
removed to shed attached sediment, and a cap is
immediately screwed onto the bottle over the inner bag.
In this study, the samplers were placed at depths of 6 to
10 in. by manual insertion behind a shovel blade driven
into the sediments or by placement in a hole formed by
the pointed end of a pickax.
Samplers at the Allen Harbor Landfill were
installed during March 16-20,1998, at locations
shown in figure 2 and retrieved during low tide on
April 1-2,1998. Most samplers (1 to 79) were installed
during low tide at intervals of about 25 ft along a
1,700-ft length of the shoreline. Samplers also were
placed at 20 selected high-tide locations (HI to H20)
(for comparison to results from the low-tide locations),
at 12 locations where ground-water was discharging in
seeps (SI to S12), and at four locations on mud flats
south of the landfill area (Ml to M4). Duplicate
samplers were placed at six low-tide locations
(locations 20, 30, 40, 50, 60, and 70).
Samplers at Calf Pasture Point were installed
during April 7-9, 1998, at locations shown in figure 3
and retrieved during April 28-29, 1998. Most samplers
were placed during low tide (samplers 1 to 30) at
intervals of 50 ft along about 1,300 ft of shoreline. The
spacing was greater on the southeast side of the study
area. Samplers were placed at the high tide level at
seven locations (H1-H7) for comparison to results from
low-tide locations. Additionally, 24 samplers (Wl to
W24) were placed in 2 wetland areas inland from the
entrance channel to Allen Harbor and in 4 seepage
areas (SI to S4) near the shore (fig. 3). Duplicate
samplers were placed at three low-tide locations
(locations 10, 20, and 30), two wetland locations (W5
and W16), and one high-tide location (HI).
Vapor samplers were analyzed onsite for VOCs
using the USEPA Region I standard air screening
method (U.S. Environmental Protection Agency, 1998).
Vapor samples were analyzed using Photovac gas
chromatograph equipped with a 4-foot by 1/8-inch SE-
30 column and photoionization detector. Samples were
analyzed within 24 hours of sample collection. Target
compounds for analysis were benzene, TCE, toluene,
PCE, chlorobenzene, ethylbenzene, meta/para-xylene,
and ortho-xylene. The reporting limits for target
compounds from the two areas are given in table 1 (in
back of report).
Locations of samples at both sites were
determined using a global positioning system (GPS).
Operation of the GPS was checked by comparing
surveyed locations with the locations of several
monitoring wells determined by GPS.
VOLATILE ORGANIC COMPOUNDS
DETECTED IN VAPOR-DIFFUSION
SAMPLERS
Volatile organic compounds were detected in
numerous vapor samplers placed at the Allen Harbor
Landfill and in a few samplers placed at the Calf
Pasture Point site. The concentrations in air, reported in
parts per billion by volume, are typically several times
higher than concentrations in water reported in
micrograms per liter (D.A. Vroblesky, oral commun.,
1998). The exchange of water between surface water
and ground water during tidal cycling could affect the
apparent concentrations of VOCs detected in vapor
samplers, but the effects of tides were not investigated
in this study. Results of vapor analyses for samplers
that contained detectable concentrations of VOCs are
reported in tables 2 and 3 (in back of report).
4 VOCs Detected in Samplers Placed in Sediments Near the Shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, R.I.
-------
Allen Harbor Landfill
REFERENCES
VOCs were detected in 41 of 115 vapor-diffusion
samplers placed near the Allan Harbor Landfill (table
2, fig. 2). TCE was the most common VOC detected in
the samplers. Other VOCs detected included benzene,
toluene, and PCE. Vapor concentrations were less than
200 ppb at all locations except 6, 33, 34 and 35. A
benzene concentration of 940 ppb was observed in
sampler 6. Elevated concentrations of TCE were
observed in sampler 33 (340,000 ppb), sampler 34
(250 ppb), and sampler 35 (19,000 ppb). An elevated
PCE concentration of 1,700 ppb was also detected in
sampler 33. VOCs were detected at several high tide
locations and at several seeps. The concentrations
detected at seeps were generally near reporting limits
(table 1) except at seep sampler S10, where 200 ppb of
TCE was detected.
Calf Pasture Point
VOCs were detected in 7 of 30 vapor samplers
placed along the shore at Calf Pasture point (table 3,
fig. 3). Concentrations ranged from a trace amount in
sampler 13 to 1,900 ppb in sampler 22. The detections
appear to be clustered near an inlet of Allen Harbor on
the west side of the study area and near a former dock
on the south side of the study area. TCE was detected
in only one (W14) of 24 samplers placed in the wetland
areas.
EA Engineering, Science, and Technology, 1996, Revised
draft final, IR Program Site 09, Allen Harbor Landfill,
Phase III remedial investigation, volumes I and II:
Technical Report, Naval Construction Battalion Center,
Davisville, Rhode Island: Sharon, Mass., 308 p.,
appendixes A-N.
1998a, Final, IR Program Site 07, Calf Pasture Point,
Phase III remedial investigation, volume I: Technical
Report, Naval Construction Battalion Center,
Davisville, Rhode Island: Bedford, Mass., 282 p.
1998b, Draft IR Program Site 09, Allen Harbor
Landfill offshore investigation report, Naval
Construction Battalion Center, Davisville, Rhode
Island: Bedford, Mass., 16 p.
Lyford, P.P., Stone, J.R., Nielsen, J.P., and Hansen, B.P.,
1998, Geohydrology and ground-water quality, Eastern
Surplus Superfund Site, Meddybemps, Maine: U.S.
Geological Survey Water-Resources Investigations
Report 98-4174, 68 p.
U.S. Environmental Protection Agency, 1998, Ambient air
grab sample analysis for volatile organic compounds:
Region I, Internal Standard Operation Procedure EIA-
FLDGRAB1.SOP, March 1998, 6 p.
Vroblesky, D.A., Rhodes, L.C., Robertson, J.F., and
Harrigan, J.A., 1996, Locating VOC contamination in a
fractured-rock aquifer at the ground-water/surface-
water interface using passive vapor collectors: Ground
Water, v. 34, no. 2, p. 223-230.
References 5
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41'37'30'
Photographic base (composite) derived from USGS digital orthophotos of portions of Wicktord and East Greenwich quadrangles,
M North American Datum 1983. The photos have been digitally retouched to reduce sunlight reflections ofl the water.
Figure 1. Location of Allen Harbor Landfill and Calf Pasture Point study areas, Davisville, Rhode
Island.
6 VOCs
Detected in Samplers Placed in Sediments Near the Shoreline at Allen Harbor Landfill and Calt Pasture Point, Davisville, R.I.
-------
521,800 FEET
523,200 FEET
197,600 FEET -
196,400 FEET -
MW09-14DO
Allen Harbor Landfill
H11
MW09-09D O i;
moi'
Base traced from U.S. Geological Survey digital orthophoto 1:12000,
GPS from Trimble Asset Surveyor, 1927 North American Datum,
Rhode Island coordinate system used
0 100
SCALE 1:600
200 300 400
500 FEET
EXPLANATION
0 20 40 60 80 100 120 METERS
55 • LOW-TIDE SAMPLER AND NUMBER
H6 o HIGH-TIDE SAMPLER AND NUMBER
M4 • MUDFLAT SAMPLER AND NUMBER
S3 e SEEP SAMPLER AND NUMBER
MW09-20I
O
SELECTED MONTORING WELL
AND NUMBER
— INDICATES VOLATILE
ORGANIC COMPOUNDS
WERE DETECTED IN
VAPOR SAMPLER
Figure 2. Locations of vapor-diffusion samplers, samplers that detected organic vapors, and selected monitoring wells, Allen
Harbor Landfill, Davisville, Rhode Island.
Figures 7
-------
523,800 FEET
525,000 FEET
197,600 FEET -
196,800 FEET —
area J wt^ wio
V Wetland
I area
Calf Pasture
Point Area
22 23 24 p. .
Former Dock ' I 21 26
20
Base traced from U.S. Geological Survey digital orthophoto 1:120OO,
GPS from Trimble Asset Surveyor, 1927 North American Datum,
Rhode Island coordinate system used
100
SCALE 1:600
200 300 400
500 FEET
0 20 40 60 80 100 120 METERS
EXPLANATION
55 • LOW-TIDE SAMPLER AND NUMBER
H6 o HIGH-TIDE SAMPLER AND NUMBER
S3 • SEEP SAMPLER AND NUMBER
W2 O WETLAND SAMPLER AND NUMBER
MW07-21S O SELECTED MONITORING WELL
AND NUMBER
— INDICATES VOLATILE ORGANIC
COMPOUNDS WERE DETECTED
IN VAPOR SAMPLER
Figure 3. Locations of vapor-diffusion samplers, samplers that detected organic vapors and selected monitoring wells, Calf
Pasture Point study areas, Davisville, Rhode Island.
8 VOCs Detected in Samplers Placed in Sediments Near the Shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, R.I.
-------
Table 1. Reporting limits for target volatile organic compounds
at Allen Harbor Landfill and Calf Pasture Point, Davisville,
Rhode Island, March-April 1998
Compound
Benzene
Trichloroethylene (TCE)
Toluene
Tetrachloroethylene (PCE)
Chlorobenzene
Ethylbenzene
meta/para-Xylene
ortho-Xylene
Reporting limit
(parts per billion by volume)
Calf
Allen Harbor _
Landfill Pa* ure
Point
10 5
10 6
35 30
20 15
70 60
90 80
90 70
100 95
Table 3. Concentrations of volatile organic compounds in
vapor-diffusion samplers at Calf Pasture Point, Davisville,
Rhode Island, April 1998
[Concentrations in parts per billion by volume in vapor; No., number; TCE,
trichloroethylene; PCE, tetrachloroethylene; trace, compound identified on
chromatograph but at a concentration below the reporting limit --, not
detected]
Sample No.
2
13
14
15
21
22
23
W14
TCE
13
trace
17
60
220
1,900
30
14
PCE
--
--
--
trace
—
-
-
-
Table 2. Concentrations of volatile organic compounds in vapor-diffusion samplers at Allen Harbor Landfill, Davisville, Rhode
Island, April 1998
[Concentrations in parts per billion by volume in vapor; D, duplicate; No., number; TCE, trichloroethylene; PCE, tetrachloroethylene; trace, compound iden-
tified on chromatograph but at a concentration below the reporting limit;--, not detected]
Sample
No.
1
2
4
5
6
22
24
25
26
27
28
30
30 D
31
32
33
34
35
36
43
44
Benzene Toluene
13
„
12
23
940
.-
13
—
„
—
—
—
..
_.
—
—
—
—
—
171 141
trace
TCE PCE
..
16
25
..
„
12
„
14
39
19
42
48
52
11
79
340,000 1,700
250
19,000
58
46
36
Sa^ple Benzene Toluene
No.
45 23
46 19 40
48
65
75
HI
H2
H3
H6
H7
H8 - 44
H10
HIS 210 140
H17
H19
S2
S3
S4
S9
S10
M3
TCE
-
-
13
trace
13
23
12
28
13
52
20
11
40
15
trace
-
trace
15
trace
200
trace
PCE
—
—
—
-
-
86
-
—
-
-
~
trace
82
trace
--
trace
-
-
-
Tables 9
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