OPERABLE UNIT THREE SDMS DocI 00023277D 8 MONITORING PROGRAM REPORT … · Government Party Comment osn the Phase 1 RI Data Report Addendum and Draft RI Report W, . R. Grace Superfund

V R

SDMS DocID 000232778 OPERABLE UNIT THREE

MONITORING PROGRAM REPORT, 2002

W.R. GRACE SUPERFUND SITE ACTON, MASSACHUSETTS

PREPARED FOR

W.R. GRACE & Co. - CONN. 62 WHITTEMORE AVENUE

CAMBRIDGE, MASSACHUSETTS 02140

PREPARED BY

GEOTRANS, INC. 6 LANCASTER COUNTY ROAD

HARVARD, MA 01451

GEOTRANS PROJECT No. 3008.002.44 MARCH 28,2003

ATETMTECHCOMPAH'f . m . 7 , IllC.

6 Lancaster County Road Harvard. Massachusetts 01451

http:3008.002.44

6 Lancaster County Road GeoT,Harvard, MA 01 451 A TETRA TECH COMPANY A Jrans,

www.geotransinc.com 978-772-7557 FAX 978-772-618? P.N. 3008.002.44

March 28, 2003

Mr. Derrick Golden Mr. Daniel Keefe Waste Management Division Bureau of Waste Site Cleanup U.S. Environmental Protection Agency MA Department of Environmental Region I Protection 1 Congress Street, Suite 1100 One Winter Street Boston, MA 02114-2023 Boston, MA 02108

RE: Operable Unit Three Monitoring Program Report, 2002 and Response to Government Party Comments on the Phase 1 RI Data Report Addendum and Draft RI Report, W. R. Grace Superfund Site, Acton, Massachusetts

Gentlemen:

Enclosed please find the Operable Unit Three Monitoring Program Report, 2002 and responses to the government party comments on the August 16, 2002 Phase 1 Remedial Investigation (RI) Data Report Addendum and the August 30, 2002 Draft RI Report. Comments were provided by:

• The United States Environmental Protection Agency (EPA) on October 4, 2002; • The Massachusetts Department of Environmental Protection (DEP) on

October 8, 2002; • Brown and Caldwell (B&C) on October 8, 2002; • The Acton Water District (AWD) on October 7, 2002; and • The EPA's Center for Subsurface Modeling Support (CSMoS) on January 26, 2002.

In order to efficiently respond to the comments, the comments were obtained electronically and sorted such that all the comments related to a particular document were grouped together. To organize the comments and still be able to track individual comments to their source, comments provided by each organization were numbered in the order they appeared in the comment letters. For example, the first comment in the letter from the United States Environmental Protection Agency is called "EPA Comment 1", the second comment in the EPA letter is called "EPA Comment 2", and so on. Once all the comments were numbered, they were grouped into the following sections:

• Comments on the Phase 1 RI Data Report Addendum; • Comments on the Draft RI Report; and • Comments on the Groundwater Flow Model, Appendix A of the Draft RI Report.

M \WP DOTS'NCW 2(X)3 I 0321131 doc

Derrick Golden and Daniel Keefe Page 2 March 28,2003

In addition, in order to minimize repetition in the responses, comments along the same vein were grouped together.

As discussed during the October 8, 2002 meeting with the government parties, the responses to comments on the Draft RI Report will be incorporated into the Draft RI/FS to be submitted in 2004. We are currently modifying the "Schedule for Operable Unit Three RI/FS Deliverables and Activities" so it is not included as an attachment. A meeting is scheduled for Wednesday, April 9, 2003 between Grace and the government parties to discuss the schedule. If you have any questions regarding this document please call me at (978)-772-7557.

Sincerely,

Anne Benjamin Sheehan V Project Manager

cc: Stephen Anderson, Anderson and Kreiger Jim Deming, Acton Water District Lydia Duff, W. R. Grace & Co. Conn. Bob Eisengrein, ACES Doug Halley, Town of Acton Seth Jaffe, Esq., Foley Hoag LLP Maryellen Johns, Remedium Michael LeBlanc, DEP Mary Michelman, ACES Michael Moore, Town of Concord Board of Health Chuck Myette, Brown & Caldwell Mitch Obradovic, Remedium Jim Okun, OT&O Barbara Weir, Metcalf & Eddy Acton Public Library

Enclosures ABS/gsk

M \WP^DOCS

OPERABLE UNIT THREE

MONITORING PROGRAM REPORT, 2002

W.R. GRACE SUPERFUND SITE ACTON, MASSACHUSETTS

PREPARED FOR:

W.R. GRACE & Co. - CONN 62 WHITTEMORE AVENUE

CAMBRIDGE, MASSACHUSETTS 02140

PREPARED BY:

GEOTRANS, INC. 6 LANCASTER COUNTY ROAD

HARVARD, MASSACHUSETTS 01451

GEOTRANS P.N. 3008.002.44 March 28, 2003 GeoTrans, Inc.

http:3008.002.44

TABLE OF CONTENTS

1 INTRODUCTION 1-1

2 WATER LEVEL MONITORING 2-1

3 GROUNDWATER QUALITY SAMPLING 3-1

3.1 VOC SAMPLING 3-1

3.1.1 MONITORING AND PUMPING WELL SAMPLING 3-1

3.1.2 SUB-RIVER GROUNDWATER SAMPLING 3-1

3.1.3 DISTRIBUTION OF VOCs 3-2

3.1.3.1 VDC DISTRIBUTION 3-3

3.1.3.2 VINYL CHLORIDE DISTRIBUTION 3-4

3.1.3.3 BENZENE DISTRIBUTION 3-5

3.1.3.4 DISTRIBUTION OF OTHER VOCs 3-5

3.1.3.5 GROUNDWATER QUALITY TRENDS 3-6

3.2 INORGANIC COMPOUND SAMPLING 3-9

4 REFERENCES 4-1

ATTACHMENT A

TABLE A-l VOC CONCENTRATIONS IN GROUNDWATER, FALL 2002

TABLE A-2 VOC CONCENTRATIONS IN GROUNDWATER, FALL 2002 (SAMPLES COLLECTED BY WOODARD & CURRAN)

TABLE A-3 VOC CONCENTRATIONS IN GROUNDWATER BENEATH THE ASSABET RIVER, ASBRV-T6

TABLE A-4 INORGANIC COMPOUND CONCENTRATIONS IN GROUNDWATER, FALL 2002

TABLE A-5 GENERAL CHEMISTRY OF GROUNDWATER, FALL 2002

ATTACHMENT B

DIFFUSIVE SUB-RIVER SAMPLING FORM

FOR W.R. GRACE & CO. - CONN i GeoTrans, Inc. M WP DOCS-N099,2003'R0206l230doc

LIST OF TABLES

TABLE 2-1 WATER LEVEL MEASUREMENTS, FALL 2002 2-3

TABLE 3-1 SUMMARY OF VOCs DETECTED IN GROUNDWATER, FALL 2002 3-12

TABLE 3-2 RESULTS OF MANN-KENDALL TREND TEST FOR SMALL SAMPLE SIZES 3-13

TABLE 3-3 SUMMARY OF INORGANIC COMPOUNDS DETECTED IN GROUNDWATER, FALL 2002 3-15

FOR W.R. GRACE & Co. - CONN GeoTrans, Inc. M \WP DOCS N099\2003l'R02061230 doc

LIST OF FIGURES

FIGURE 2-1 UNCONSOLIDATED DEPOSITS POTENTIOMETRIC CONTOUR MAP - NOVEMBER 2002.

FIGURE 2-2 BEDROCK POTENTIOMETRIC CONTOUR MAP - NOVEMBER 2002

FIGURE 3-1 ASSABET RIVER DAILY AVERAGE FLOW, 2002 FIGURE 3-2 VDC, VINYL CHLORIDE, AND BENZENE CONCENTRATIONS IN UNCONSOLIDATED

DEPOSITS GROUNDWATER, FALL 2002

FIGURE 3-3 VDC, VINYL CHLORIDE, AND BENZENE CONCENTRATIONS IN BEDROCK GROUNDWATER, FALL 2002

FIGURE 3-4 DISTRIBUTION OF VDC IN GROUNDWATER, FALL 2002 FIGURE 3-5 DISTRIBUTION OF VINYL CHLORIDE IN GROUNDWATER, FALL 2002 FIGURE 3-6 DISTRIBUTION OF BENZENE IN GROUNDWATER, FALL 2002 FIGURE 3-7 DISTRIBUTION OF VDC IN GROUNDWATER, PRE-1984

FOR W.R. GRACE & Co. - CONN 111 GeoTrans, Inc. M AVP DOCS N099

LIST OF ACRONYMS

1,2-DCA ARAR ARS cfs FSP gpm Grace OU-3 PRO QAPP RI Site TCE trend test US EPA USGS VDC VOC

1,2-dichloroethane Applicable and Relevant Appropriate Requirement Aquifer Restoration System cubic feet per second Field Sampling Plan gallons per minute W.R. Grace & Co. - Conn. operable unit 3 preliminary remediation goal Quality Assurance Project Plan Remedial Investigation W.R. Grace & Co. - Conn. Acton Superfund Site trichloroethene Mann-Kendall trend test for small sample sizes United States Environmental Protection Agency United States Geological Survey 1,1-dichloroethene or vinylidene chloride volatile organic compound

FOR W.R. GRACE & Co. - CONN IV GeoTrans, Inc. M-\WP DOCS N099,2003'R0206I230 doc

1 INTRODUCTION

This report presents the results of the Operable Unit Three (OU-3) monitoring done at the

W. R. Grace Superfund Site in Acton, Massachusetts (the Site) in 2002. The current OU-3

monitoring program was defined in Section 6 of the August 30, 2002 Draft Remedial

Investigation Report (RI) (GeoTrans, 2002b) with modifications as summarized in the Meeting

Summary of the October 8, 2002 meeting that was submitted to the government parties on

October 16, 2002 (Grace, 2002). This revised groundwater monitoring program does not include

treatment system monitoring. Treatment system monitoring will continue to be done in

accordance with the Amended Monitoring Plan (CDM, 1996). The goals of the Site groundwater

monitoring program include:

• Water level monitoring to confirm that the planned groundwater ARS capture zones are being achieved;

• Water quality monitoring within the ARS capture zones to assess the effectiveness of the ARS and the source control measures on reducing contaminant concentrations in groundwater; and

• Water quality monitoring outside of the ARS capture zones to assess the effectiveness of the ARS at containing the migration of contaminated groundwater and the natural attenuation of groundwater contamination beyond the ARS capture zones.

The groundwater monitoring program will be re-evaluated again as part of the OU-3

remedy implementation.

FOR W.R. GRACE & Co. - CONN 1-1 GeoTrans, Inc. M-'.WP DOCS'J\0')9\2003'R0206I230 doc

2 WATER LEVEL MONITORING

A Site-wide water level measurement round was done on November 13, 14, and 15,

2002. All the public water supply wells were pumping at the time the measurements were

collected with one exception. The Scribner wellfield was pumping at approximately 45 gallons

per minute (gpm) on November 13, 2002, but was not pumping on November 14 and 15, 2002.

Table 2-1 summarizes the water levels measured on November 13 through 15, 2002. Figures 2-1

and 2-2 illustrate the water levels measured in the wells open to the unconsolidated deposits and

bedrock, respectively. Also shown on the figures are the model-generated captures zones for the

Aquifer Restoration System (ARS). The capture zones depicted on Figures 2-1 and 2-2 were

simulated using long-term average stage elevations from the Assabet River, Fort Pond Brook,

and the three on-Site ponds and the average pumping rates measured in the ARS wells in 2001,

as described in Section 3.2 of Appendix A of the Draft RI (GeoTrans 2002b). Figures 2-1 and

2-2 show that groundwater beneath most of the former source areas at the Site is being captured

by the ARS. Beyond the ARS capture zone, groundwater flows to the south and southeast

toward the Assabet River, and to the northwest toward Fort Pond Brook. A groundwater high

extends onto the BOC Gases property to the northeast. Groundwater from this area flows to the

northwest, north, and northeast toward Fort Pond Brook.

Water level data from monitoring well clusters located northeast of the Grace property

clearly illustrate a northwesterly hydraulic gradient in the unconsolidated deposits from AR-32D,

AR-33D, and AR-34D toward the Acton Water District public water supply wells and Fort Pond

Brook (Figure 2-1). The bedrock water level data also indicates a northwesterly hydraulic

gradient from the AR-34 cluster toward the public water supply wells and Fort Pond Brook

(Figure 2-2). The water level data show that groundwater flow in the unconsolidated deposits

and bedrock is toward the public water supply wells and Fort Pond Brook in this area. The data

do not indicate that contaminated groundwater from the Grace property migrates beyond the

public water supply wells. It is either captured by the public water supply wells or discharges to

Fort Pond Brook.

FOR W.R. GRACE & Co. - CONN 2-1 GeoTrans, Inc. M \WP DOCS''N099*2003'.R0206]230.doc

Vertical hydraulic gradients are downward across most of the Site. Vertical hydraulic

gradients are upward at most locations near the Assabet River and Fort Pond Brook indicating

that the river and brook are groundwater discharge boundaries for bedrock and unconsolidated

deposits groundwater. Upward vertical hydraulic gradients were also observed at some

monitoring wells located adjacent to pumping wells.

FOR W.R. GRACE & Co. - CONN 2-2 GeoTrans, Inc. M VVP DOCS NOW\2003M*0206123Ci doc

Table 2-1. Water Level Measurements, Fall 2002.

Location

73-3

73-4

77-2

77-3

9-78

A-2E

A4-78

A5-78

A6-78

A7-78

AR-01P

AR-02P

AR-03P

AR-04P

AR-05

AR-06P

AR-07P

AR-08P

AR-09A

AR-09BR

AR-09P

AR-10BR

AR-10P

AR-11P

AR-11SBR

AR-12

AR-12D

AR-12DBR

AR-12SBR

AR-13P

AR-14P

AR-15P

AR-16ADP

AR-16BSH

AR-17ASH

AR-17BDP

AR-18P

AR-19ASH

AR-19BDP

AR-20

Open Interval Elevation

(feet NGVD)

73 to 83

48 to 58

63 to 68

46 to 51

58 to 62

74 to

98 to 103

88 to 93

80 to 85

72 to 77

122 to 132

120 to 130

120 to 130

1 26 to 1 3 1

126 to 131 (BR)

132 to 137

138 to

124 to 129

68 to 71

57 to 62 (BR)

129 to 134

8 t o l 8 ( B R )

124 to 134

122 to 127

60 to 70 (BR)

103 to 113

74 to 84

l l t o 2 0 ( B R )

49 to61(BR)

117 to 122

120 to 125

128 to 133

73 to 83 (BR)

110 to 120

118 to 128

1 0 4 t o l l 4 ( B R )

101 to 106

122 to 127

84 to 104

87 to 92 (BR)

Date

Measured

11/13/02

11/13/02

11/13 /02

11/13/02

11/13 /02

11/13/02

11/13 /02

11/13 /02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

H/13'02

11/13/02

1 1 / 1 3 0 2

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

I l / 1 3 ' 0 2

1 1 / 1 4 0 2

11/14/02

' 11/14/02

11/14/02

11/14/02

11/14/02

11/13/02

11/14/02

' 11/13/02

" 11/13/02

11/13/02

11/13/02

11/13/02

11/15/02

11/13/02

11/13/02

11/14/02

Measuring Point Elevation

(feet NGVD)

13096

138.11

133.63

134.26

137

1327

134.98

132.32

138.55

136.12

139.91

137.38

153.96

171.12

198.8

199.67

202.7

141.39

186.34

188.39

187.84

190.17

191.68

141.37

139.8

141.45

142.4

142.4

142.4

142.75

152.31

160.93

137.46

137.53

143.01

145.09

185.12

184.22

184.92

147.72

Depth to Water (feet)

796

9.51

821

728

1 1 24

10.57

NM

754

1323

987

DRY

DRY

18.31

36.98

6625

63.97

5864

11.99

55 35

5749

52.91

5855

57

1485

13.25

18.43

18.26

16.22

16.2

15.34

25.66

28.46

8.01

8.31

13.73

15.39

52.77

51 34

53.49

20 73

Water Level Elevation

(feet NGVD)

123

1286

12542

12698

12576

122 13

KM

12478

125.32

126.25

DRY

DRY

135 65

134 14

132 55

135 7

14406

1294

130.99

1309

1 34 93

131 62

1 34 68

126.52

12655

123.02

124.14

126 18

1262

127.41

126.65

132.47

129.45

129.22

129.28

129.7

132.35

13288

131 43

1 26 99

P \project\urgaclon database acccssIOOO NO*Ndb mdb - RPT WLelcv 1102 GeoTrans, Inc.

Table 2-1. (continued) Open Interval

Elevation Location (feet NGVD)

AR-20A 123 to 133

AR-21 78 to 83 (BR)

AR-21A 103 to 113

AR-21B 131 to 136

AR-22 106 to 116

AR-23 9 8 t o l 0 3 ( B R )

AR-23A 116 to 126

AR-23B 129 to 144

AR-25B ' 52 to 57 (BR)

AR-25D 89 to 99

AR-25S 124 to 134

AR-26D 87 to 97

AR-26DBR 27 to 47 (BR)

AR-26S 112 to 122

AR-26SBR 53 to 70 (BR)

AR-27D 104 to 114

AR-27S 124 to 134


AR-28D 85 to 95

AR-28DBR ! 43 to 54 (BR)

AR-28S 115 to 125


AR-29D , 91 to 101


AR-29S 126 to 136


AR-30D 75 to 85

AR-30DBR 2 2 t o 4 1 ( B R )

AR-30S 105 to 115

AR-30SBR 47to61(BR)

AR-31D 82 to 92

AR-31DBR 14 to33 (BR)

AR-31S 112 to 122

AR-31SBR 51 to67(BR)

AR-32D 97 to 102

AR-33D 117 to 133

AR-34D 139 to 144


AR-34SBR 1 0 0 t o l 2 0 ( B R )

ASSABET1 i 71 to 80

Date Measured

11/14/02

11/14/02

11/14/02

11/14/02

11/14/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/14/02

11/14/02

11/14/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/14/02

11/14/02

11/14/02

11/14/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/14/02

11/14/02

11/14/02

11/14/02

11/14/02

Measuring Point Water Level DePth to Water Elevation Elevation

(feet)(feet NGVD) (feet NGVD)

147.8 18.66 129.14

197.8 70.99 j 126.81

197.61 71.06 126.55

197.71 64.52 133.19

148.47 27.92 120.55

165.99 34.32 131.67

165.81 34.21 131.6

165.53 33.74 131.79

192.82 61.34 131.48

195.01 59.95 135.06

193.02 58.81 134.21

190.6 60.61 129.99

190.6 60.12 130.48

190.6 55.5 135.1

190.6 60.68 129.92

148.3 18.97 129.33

148.3 13.16 135 14

148.3 17.41 130.89

148.56 23.05 125.51

148.56 22.86 125.7

148.56 23.48 125.08

148.56 23.04 125.52

162.8 39.22 123.58

162.8 38.3 124.5

162.8 37.63 125.17

162.8 39.27 123.53

125.1 3.46 121 64

125.1 2.98 122.12

125.1 ' 3.03 122.07

125.1 ' 2.76 122.34

139.97 19.16 120.81

139.97 12.05 127.92

139.97 19.38 120.59

139.97 15.83 124.14

139.48 17.76 121.72

172.79 39.8 132.99

184.87 36.63 148.24

184.85 44.43 140.42

184.79 42.81 141.98

138.7 32.21 106.49

GeoTrans, Inc. P 'project'.wrgaccon database aicess2000'N"09?db mdb - RPT WLclev 1102

Table 2-1. (continued)

Location

ASSABET-2A

B-01P

B-03P

B-04P

B-06P

B-08A

B-08B

B-08C

B-08D

B-10P

BD-2

CHRISTOFFER

CLF-101

CLF-102

CLF-103

CLF-104

CLF-105

CLF-106

CLF-107

CLF-108

CLF-1P

CLF-2A

CLF-2B

CLF-2C

CLF-3A

CLF-3B

CLF-3C

EL-3

ELF

ELF-OBS

G-l

G-2

G-3

G-3A

G-3BR

LAWSBROOK

LF-01P

LF-02A

LF-02P

LF-03A

Open Interval Elevation

(feet NGVD)

98 to 106

133 to 136

118 to 121

1 2 8 t o l 3 1

1 1 0 t o l l 3

15 to 25 (BR)

76 to 86

108 to 118

125 to 140

128 to 131

124 to 134

86 to 96

115to 125

118 to 128

117to 128

115 to 125

113 to 123

113 to 123

114 to 124

H 5 t o 125

120 to 125

84 to 89

104 to 109

114 to 124

116 to 126

1 0 6 t o l l l

86 to 91

123 to 128

97 to 137

97 to 102

135 to 138

132 to 135

125 to 128

43 to 53

10 to 20 (BR)

108 to 118

1 26 to 1 31

35 to 45 (BR)

119 to 124

1 3 t o 2 3 ( B R )

Date

Measured

l l /14 '02

11/13/02

11/14/02

11/13/02

11 /1302

11/13/02

11/13/02

11/13/02

11/13/02

11/14/02

11/13/02

11/14/02

11/14/02

11/14/02

11/14/02

11/14/02

11/14'02

11/14'02

11/14/02

11/14/02

11/14/02

11/14'02

11/14/02

11/14/02

11/14/02

11/14/02

11/14/02

11/13/02

11/14/02

11/14/02

11/13/02

11/13/02

11/13/02

11/13/02

11/13/02

11/14/02

11/13/02

11/13/02

11/13/02

11/13/02


(feet NGVD)

13456

17828

1623

16806

139 13

199 17

199 15

19907

199 14

19354

19591

126 1

14564

13306

13308

133 86

133 34

133 85

13491

141 93

15399

13165

12981

131 78

132 1

13323

13386

16996

19735

19797

201 75

19831

192 13

191 82

19245

1605

19273

19872

19822

19963


1693

4478

NV1

31 98

15 71

6794

6764

65 79

6535

5929

61 8

1805

2098

8 13

8 14

10 11

5 95

9 16

962

1727

2884

782

6 6 1

724

738

793

975

3637

739

6878

6459

64 1

5775

5875

5991

3925

5852

6755

67

6879


(feet NGVD)

1 1 7 6 3

H3 5

N\1

13608

12342

1 3 1 23

131 51

m 28

m 79 13425

134 11

10805

12466

12493

12494

123 75

12739

12449

125 29

12466

125 15

12183

1212

12454

12472

125 3

124 11

13359

12345

129 19

137 16

13421

13438

13307

13254

121 25

13421

131 17

131 22

13084

P \projcct »rgaclondauba5eau.e5s2000 \099dbmdb RPT WLctevll02 GeoTrans, Inc.


Location

LF-03P

LF-04P

LF-05A

LF-05B

LF-05C

LF-05D

LF-05E

LF-05P

LF-06

LF-06C

LF-06N

LF-06S

LF-09

LF-09A

LF-09B

LF-10

LF-10A

LF-10B

LF- 1 OC

LF-I1AR

LF-11BR

LF-11CR

LF-11R

LF-12

LF-12A

LF-13

LF-13A

LF-13B

LF-13SBR

LF-14

LF-15

LF-16

LF-17D

LF-17S

LF-I7SBR

LF-18D

LF-18DBR

LF-18SBR

LF-19D

LF-19S

Open Interval Elevation Date

Measuring Point Elevation DeP* to Water


(feet NGVD) Measured (feet NGVD) (feet) (feet NGVD)

123 to 128 11/14/02 201.01 66.48 13453 1 127 to 137 11/13/02 199.42 68.13 131 29

125 to 135 11/13/02 199.74 65.05 134.69

126 to 136 11/13/02 198.55 64.65 133.9

125 to 135 11/13/02 197.9 6397 13393

82 to 92 11/14/02 19942 6769 131 73

96 to 106 11/13/02 197.15 6465 1325

132 to 137 11/13/02 199.64 DRY DRY

3 1 t o 4 1 ( B R ) ; 11/13/02 197.56 69.97 12759

110 to 120 11/13/02 198.62 6883 129.79

90 to 95 (BR) ll7T3/02 198.21 6995 128.26

132 to 137 11/13/02 198.62 < 64.94 133 68

80 to 95 11/14/02 200.28 68.81 131 47

113 to 127 11/13/02 200.35 69.02 131.33

128 to 138 11/13/02 200.49 69.46 131.03

35 to 45 11/13/02 199.47 67.45 13202

56 to 71 11/13/02 199.75 67.73 132 02

78 to 86 11/13/02 199.4 6762 131 78

128 to 138 11/13/02 19949 65 15 13434

40 to 50 ' 11/13/02 195.6 6325 132.35

85 to 95 ' 11/13/02 195.88 62.42 133.46

127 to 137 ' 11/13/02 195.65 60.63 13502

- l l t o - l ( B R ) 11/13/02 195.63 6433 131 3

88 to 98 11/13/02 199.65 7058 129.07

127 to 137 11/13/02 199.83 6961 130.22

14 to 24 (BR) 11/14/02 128.95 3.05 i 125.9

90 to 100 11/14/02 129.27 6.28 i 12299

115 to 125 ' 11/14/02 129.07 6.1 122.97

68 to 78 (BR) 1 11/14/02 128.5 3.1 125.4

120 to 130 11/13/02 184.14 50.46 133.68

HO to 130 11/14/02 199.96 66.23 133.73

119 to 129 11/14/02 194.74 60.93 133.81

83 to 93 11/14/02 200.8 ' 72.35 128.45

113 to 123 11/14/02 200.8 67.8 133

56 to 62 (BR) ~ 11/14/02 200.8 72.98 127.82

53 to 63 11/14/02 133.81 9.59 12422

-15 to -5 (BR) 11/14/02 133.75 8.45 125.3

3 1 t o 4 1 ( B R ) 11/14/02 133.84 8.25 i 12559

50 to 60 11/13/02 198.1 67.71 ' 13039

110 to 130 11/13/02 198.1 65.61 13249

GeoTrans, Inc. P ''pfojeclWrgacton',database atocss2


Location

LF-19SBR

LF-20D

LF-20DBR

LF-20SBR

LF-21D

LF-21DBR

LF-21SBR

MLF

MW-01B

MW-01D

MW-01S

MW-02B

MW-03D

MW-03S

MW-04B

MW-04D

MW-04S

MW-06B

MW-06D

MW-06S

MW-07B

MW-07D

MW-07S

MW-08S

MW-10S

MW-13B

MW-15S

MW-16B

NLBR

NLBR-R

NLGP

NMGP

OSA-01A

OSA-01B

OSA-01BR

OSA-01C

OSA-02A

OSA-02B

OSA-02BR

OSA-03A


Measuring Point Elevation Depth to Water


Ifeet NGVD) Measured (feet NGVD) (feet) (feet NGVD)

11 t o 2 3 ( B R ) 11/13/02 198.1 67.8 130.3

34 to 44 11/14/02 150.16 2557 12459

-53 to -43 (BR) 11/14/02 ' 150.46 ' 2536 125.1

-1 t o9 (BR) 11/14/02 150.16 2481 12535

61 to 71 11/14/02 156.78 29.08 1277

-30 to -20 (BR) ' 11/14/02 158.22 31 52 1267

41 to 51 (BR) 11/14/02 156.89 30.03 126.86

83 to 123 ' 11/14/02 199.6 69.51 130.09

39 to 44 (BR) 11/13/02 192.61 57.26 135.35

79 to 89 11/13/02 192.33 57.02 135.31

133 to 148 11/13/02 192.69 57.27 135.42

29 to 34 (BR) 11/13/02 194.84 61.94 132.9

108 to 118 11/13/02 191.38 61.42 129.96

129 to 144 11/13/02 191.35 61 25 130 1

36 to 41 (BR) 11/13/02 190.44 136.32 54.12

106 to 116 11/13/02 19061 57.18 13343

132 to 147 11/13/02 19057 5832 13225

40 to 45 (BR) 11/13/02 186.89 55.56 131 33

1 1 1 to 121 1 1/13/02 187.2 53.92 133.28

125 to 140 1 1/13/02 186.92 54.64 13228

49 to 59 (BR) 11/13/02 190.79 59.58 131.21

98 to 108 11/13/02 190.97 55.03 13594

129 to 144 11/13/02 19098 54.37 13661

128 to 143 11/13/02 183.67 48.33 13534

128 to 143 i 11/13/02 194.58 58.02 13656

45 to 55 (BR) ' 11/13/02 185.3 54.49 130.81

135 to 145 * 11/13/02 192.57 56.56 13601

73 to 93 (BR) 11/13/02 191.36 60.04 131 32

76 to 86 (BR) 11/14/02 182.76 53.31 12945

75 to 89 (BR) 11/14/02 183.1 56.71 126.39

93 to 108 "" 11/15/02 182.91 82.46 ' 100.45

101 to 116 11/14/02 143.22 ' 15.32 ' 127.9

128 to 138 11/13/02 195.78 62.02 13376

98 to 108 11/13/02 196.6 63.11 133.49

62 to 72 (BR) 11/13/02 195.99 64.25 131.74

80 to 90 11/13/02 196.24 63 13324

130 to 140 11/13/02 196.06 61.93 134 13

104 to 114 11/13/02 195.8 62 14 133.66

49 to 69 (BR) 11/13/02 196.42 6425 132.17

128 to 138 11/13/02 194.06 59.79 134.27

P ^projeclWrgactori database ac


Location

OSA-03B

OSA-03BR

OSA-04

OSA-05A

OSA-05B

OSA-05BR

OSA-06A

OSA-06B

OSA-06BR

OSA-07A

OSA-07B

OSA-08R

OSA-09A

OSA-09B

OSA-10A

OSA-10B

OSA-11A

OSA-11B

OSA-11BR

OSA-12A

OSA-12B

OSA-12BR

OSA-13A

OSA-13B

OSA-13C

OSA-14A

OSA-14B

OSA-14BR

OSA-15A

OSA-15B

OSA-16A

OSA-16B

OSA-16BR

OSA-17

OS A- 18

OSA-19

OSA-20

OSA-21

OSA-22

OSA-23A


(feet NGVD) Measured

104 to 114 11/13/02

55 to 65 (BR) 11/13/02

130 to 140 11/13/02

128 to 138 11/13/02

100 to 110 11/13/02

70 to 80 (BR) 11/13/02

125 to 135 11/13/02

101 to 111 11/13/02

51 to 61 (BR) 11/13/02

127 to 137 11/13/02

89 to 99 11/13/02

to 11/13/02

126 to 136 11/14/02

86 to 96 11/14/02

129 to 139 11/13/02

99 to 109 11/13/02

126 to 136 11/13/02

108 to 118 11/13/02

78 to 88 (BR) 11/13/02

125 to 140 11/13/02

68 to 78 11/13/02

37 to 47 (BR) 11/13/02

123 to 138 11/13/02

105 to 115 11/13/02

73 to 83 i 11/13/02

125 to 135 11/13/02

79 to 89 ! 11/13/02

- l t o 9 ( B R ) ' 11/13/02

129 to 139 fl/ 13/02

73 to 83 ' 11/13/02

129 to 139 11/14/02

54 to 64 11/14/02

7 t o l 7 ( B R ) ' 11/14/02

128 to 138 11/13/02

133 to 143 11/13/02

134 to 144 11/13/02

142 to 152 11/13/02

135 to 145 11/13/02

120 to 130 ' 11/13/02

129 to 139 1 11/13/02


(feet NGVD)

19422

194.47

19689

15289

15294

152.86

141.22

141 52

141 29

149.58

149.4

153.1

188.94

189

183.22

183.16

183.7

184.09

183.5

184.4

184.45

184.64

177.43

176.71

177.54

175.3

175.23

175.17

180.37

181.08

188.83

188.89

188.33

169.26

165.73

178.2

196.27

189

171.58

179.07


6008

6347

62.97

1948

21 52

21.39

9.72

10.18

997

17.29

18.1

20.15

54.67

55.91

48.93

50.7

5047

51.61

5502

49.84

50. 18

50.66

44.33

43.85

44.98

41.19

41.03

42.9

47.2

51.21

54.4

56.29

55.81

27.13

DRY

DRY

48.96

53.3

36.89

45.34


(feet NGVD)

134.14

131

133 92

13341

131.42

1 3 1 .47

131 5

131.34

131.32

132.29

131.3

13295

13427

133 09

134.29

132.46

133.23

132.48

12848

13456

13427

133.98

133 1

132.86

132.56

134 11

134.2

132.27

133.17

129.87

134.43

132.6

132.52

142.13

DRY

DRY

147.31

135 7

13469

133 73

P v>project1'wrgacton'daiabasc\acccss20001N099db mdb - RPT Wl^clcvl 102 GeoTrans, Inc.

Table 2-1. (continued) Open Interval Measuring Point Water Level

Elevation Date Elevation Depth to Water Elevation Location (feet NGVD) Measured (feet NGVD) (feet) (feet NGVD)

OSA-23B 1 1 5 to 125 11/13/02 17922 4676 13246

OSA-24 74 to 89 (BR) 11/13/02 183 5459 12841

OW-8 110 to 115 11/13/02 1 29 1 7 62 121 48

OW-B 87 to 92 11/13/02 1423 2262 1 1 9 6 8

OW-E 98 to 103 11/13/02 138 1845 1 1 9 5 5

PL-4P 131 to 134 11/13/02 1634 DRY DRY

PS-22A 124 to 126 11/13/02 1432 1925 12395

PS-22B 96 to 98 11/13/02 1432 1956 1 23 64

PS-29A 1 1 7 to 1 19 11/13/02 141 69 16 1 25 69

PS-29B 86 to 91 11/13/02 141 39 1573 12566

PT-01P 120to 130 "Tl7 13/02 13554 1402 121 52

PT-02P 123 to 128 11/13/02 13458 DRY DRY

PT-03P 121 to 126 11/13/02 13857 1507 123 5

PT-04P 118 to 123 11/13/02 1359 DRY DRY

PT-05P 122 to 132 i 11/13/02 13725 DRY DRY

PT-09 43 to 53 11/13/02 13465 1005 1246

PT-10 103 to 108 11/13/02 13523 106 1 24 63

PT-1IP 114 to 124 11/13/02 13333 839 12494

PT-12 126 to 136 11/13/02 15354 18 19 135 15

R-l 44 to 49 (BR) 11/13/02 15598 2968 1263

R-2 65 to 70 (BR) 11/13/02 13803 1262 12541

R-2A 86 to 91 11/13/02 13886 1254 126 32

R-3P 76 to 81 11/13/02 14597 2025 125 72

R-4 36 to 41 (BR) 11/13/02 139 1 1 1051 1286

R-4A to 11/13/02 14059 1064 1 29 95

R-5 33 to 38 (BR) ' 11/13/02 13902 126 12642

RLF 105 to 114 11/14/02 14701 3659 11042

RP-I 53 to 63 (BR) 11/14/02 13866 6458 7408

SCRIBNER to 11/13/02 1383 NM NM

SL-5P 1 22 to 1 3 1 11/13/02 18089 4491 13598

SL-9 125 to 130 11/14/02 ' 1 79 95 45 49 1 34 46

SLBR 39 to 49 (BR) 11/14/02 18123 555 12573

SLGP 70 to 90 11/14/02 18219 5235 12984

SLGP-R 66 to 83 ' 11/14/02 1819 NM NM

TCA-1 121 to 126 11/13/02 18362 503 133 32

TF-1 114 to 11/14/02 191 49 NM NM

TW-2-78 71 to 76 11/13/02 151 61 1775 H386

UNA-1 l l l t o 11/13/02 14357 1807 1255

UNA-2 97 to 11/13/02 13839 12 12639

UNA-3 103 to 11/13/02 15479 275 12729

P \projerfwrgactonyalabase access2000 NO'Wdb mdb RPT WUIc»1102 GeoTrans, Inc.

Table 2-1. (continued) Open Interval

Elevation Location (feet NGVD)

UNA-5 1 1 1 to

WLF 86 to 104

WLF-OBS 92 to 117

WRG-1 84 to 99

WRG1-OBS 1 02 to

WRG2-OBS 103 to

Note:

(BR) - Open interval in bedrock.

Date Measured

11/13/02

11/14/02

11/13/02

11/14/02

11/13/02

11/13/02

Measuring Point Water Level Elevation DsP& to Water Elevation

(feet NGVD) (feet) (feet NGVD1

157.75 25.54 132.21

198.64 92.8 105.84

199.15 68.13 131.02

138.7 NM | NM

146.18 20.63 ! 125.55

146.83 18 .11 | 128.72

GeoTrans, Inc. P \projecl\wrgactori

TARGET SHEET

THE MATERIAL DESCRIBED BELOW WAS NOT SCANNED BECAUSE:

(X) OVERSIZED MAP

() NON-PAPER MEDIA

() OTHER:

DOC ID: 232778 DATE- 03/28/2003 TITLE: Monitoring Program Report, 2002 DESCRIPTION: Figure 2-1: Unconsolidated Deposits Potentiometric

Contour Map, November 2002

THE OMITTED MATERIAL IS AVAILABLE FOR REVIEW BY APPOINTMENT

AT THE EPA NEW ENGLAND SUPERFUND RECORDS CENTER, BOSTON, MA

TARGET SHEET


(X) OVERSIZED MAP

() NON-PAPER MEDIA

() OTHER:

DOC ID: 232778 DATE- 03/28/2003 TITLE: Monitoring Program Report, 2002 DESCRIPTION: Figure 2-2: Bedrock Potentiometric Contour Map,

November 2002



3 GROUNDWATER QUALITY SAMPLING

Groundwater sampling was conducted between October 14, 2002 and November 12, 2002.

Groundwater samples were analyzed for volatile organic compounds (VOCs), inorganic

compounds, and general chemistry parameters. GeoTrans performed an enhanced Tier 1 validation

of the VOC and inorganic compound results. The data were checked for completeness and the

quality control sampling results were reviewed. Data were qualified, as necessary, based on the

criteria summarized in Tables 3-2 and 3-5 of the Quality Assurance Project Plan (QAPP) (HSI

GeoTrans, 2000b). In addition, the data were qualified, as necessary, based on holding times and

preservation. The groundwater sampling results are summarized below.

3.1 VOC SAMPLING

Groundwater samples were collected for VOC analysis from monitoring and pumping

wells and from beneath the Assabet River. These results are described in the following sections.

3.1.1 MONITORING AND PUMPING WELL SAMPLING

Groundwater sampling was conducted between October 14, 2002 and November 12, 2002.

Samples were collected from 101 wells for VOC analysis. Groundwater sampling was done

according to the procedures outlined in the Field Sampling Plan (FSP) (HSI GeoTrans, 2000a).

The results of these analyses are included in Table A-l of Attachment A. Two monitoring wells,

LF-06S and AR-30DBR, that were part of the planned OU-3 annual sampling round were not

sampled. LF-06S was not sampled because of the low water table at the time of sampling and

AR-30DBR did not recharge sufficiently for sampling. Groundwater samples for VOC analysis

were also collected from eleven locations by Woodard & Curran as part of the Phase 1 Initial Site

Investigation of the Debris Area off of Knox Trail (Woodard & Curran, 2002). These results are

included in Table A-2 of Attachment A.

3.1.2 SUB-RIVER GROUNDWATER SAMPLING

In addition to the groundwater samples collected from wells, groundwater samples were

collected from beneath the Assabet River at transect ASBRV-T6 to evaluate discharge of

contaminated groundwater to the river. On October 9, 2002 water-filled diffusive samplers were

deployed beneath the Assabet River at transect ASBRV-T6. The water-filled diffusive samplers

consisted of plastic bags filled with water. The sample location naming convention was as

FOR W.R. GRACE & CO. - CONN 3-1 GeoTrans, Inc. M ' \ \ P IXX SN099 2003 J102061230 doc

follows: location 'A' was one-quarter of the distance across the river from the bank closest to the

Grace Site, location 'B' was one-third of the distance, location 'C' was in the center of the river

and location 'D' was two-thirds of the distance across the river. The samplers were placed

approximately six-inches beneath the riverbed at each location and marked with flagging tape.

The samplers were removed from the river on November 4, 2002. The results of these analyses

are included in Table A-3 of Attachment A.

A piezometer was installed at transect ASBRV-T6 to determine the direction of the

vertical hydraulic gradient. The water level inside the piezometer (which represents the

groundwater head) and the river water level were measured during installation and retrieval of

the samplers. Upward vertical hydraulic gradients of 0.01 and 0.06 were measured during the

installation and retrieval, respectively. This indicates that groundwater was discharging to the

river. Measurements collected during sampler installation and retrieval are included on the

diffusive sub-river sampling form located in Attachment B.

Daily average flow in the Assabet River, as measured at the United States Geological

Survey (USGS) gauging station located approximately 1.5 miles upstream of the Site in

Maynard, ranged between approximately 19 and 166 cubic feet per second (cfs) during the time

period when the diffusive samplers were in the river. Figure 3-1 is a graph showing the flow rate

in the river during 2002. The diffusive sampling was done during low river flow conditions to

ensure that upward hydraulic gradients were maximized and that the samples equilibrated to

discharging groundwater and not to recharging surface water. The location of transect

ASBRV-T6 is shown on Figure 3-2.

3.1.3 DISTRIBUTION OF VOCs

This section describes the current distribution of VOCs detected in groundwater. Table

3-1 lists VOCs detected in groundwater since October 2002. Table 3-1 compares the VOC

results to the Screening Value for each compound. The Screening Value is the minimum

applicable or relevant and appropriate requirement (ARAR) each compound or, for compounds

with no ARAR, it is based on the US EPA Region 9 preliminary remediation goal (PRG).

Details regarding the basis for the Screening Values can be found in Section 3.2 of the Draft RI

Report (GeoTrans, 2002b). The Screening Values are being used to aid in describing the data

FOR W.R. GRACE & CO. - CONN 3-2 GeoTrans, Inc. M > W P DOCS NIW9'2003 R0206l230doc

and they are not proposed or intended to be cleanup standards for the Site. The following are

listed in Table 3-1 for each compound:

• The Screening Value;

• The number of locations in which the compound was detected above the Screening Value;

• The total number of locations for which the compound was analyzed;

• The number of samples in which the compound was detected at concentrations above the Screening Value;

• The total number of samples for which the compound was analyzed;

• The number of samples in which the compound was detected; and

• The maximum detected concentration.

Compounds detected above the Screening Value are marked with an asterisk on the right

side of the table and Screening Values that are based on the PRG are marked with a number

symbol.

As indicated in Table 3-1, samples for VOC analysis were collected from a total of 112

locations in October and November 2002. Twenty four VOCs were detected. Of the 24 VOCs

detected, nine were detected at concentrations above their Screening Value. This section

describes the distribution of the nine compounds that had concentrations exceeding their

Screening Value since October 2002.

Three compounds, 1,1-dichloroethene (VDC), vinyl chloride, and benzene, were the

compounds most frequently detected above their Screening Values and were the most widespread

in their occurrence. Figures 3-2 and 3-3 illustrate the VDC, vinyl chloride, and benzene

concentrations in groundwater samples collected from wells open to the unconsolidated deposits

and bedrock, respectively. Also indicated on Figure 3-2 are the results of the analyses of the

groundwater samples collected from beneath the Assabet River, as described in Section 3.1.2 of

this report.

3.1.3.1 VDC DISTRIBUTION

VDC was detected above the Screening Value of 7 ug/L at 50 of 112 locations, with a

maximum concentration of 570 ug/L. Figure 3-4 shows the maximum VDC concentration,

regardless of depth, detected in groundwater samples collected between October 14, 2002 and

FOR W.R. GRACE & Co. - CONN 3-3 GeoTrans, Inc. M v\VP DOCS NOW.2003vR02U6l230.doc

November 12, 2002, the most recent Site-wide sampling round. The Screening Value of 7 ug/L

was used as the minimum contour interval on Figure 3-4. The highest concentrations of VDC,

exceeding 300 ug/1, were detected in deep unconsolidated deposits and shallow bedrock

groundwater adjacent to the southwestern edge of the Industrial Landfill, in monitoring well

clusters LF-10 and LF-19, respectively.

There is a noticeable change in the distribution of VDC in groundwater between the 2002

annual sampling round and the 2001/2002 sampling results reported in the Draft RI Report

(GeoTrans, 2002b). The VDC concentrations in monitoring well cluster AR-09 located northeast

of the former Slowdown Pit have fallen below the Screening Value of 7 ug/L. As discussed in

Section 3.3.1 of the Draft RI Report (GeoTrans, 2002b), the data indicate that the ARS has cut

off the VDC contaminated groundwater that is beneath the northeastern portion of the BOC

Gases property and the southwestern portion of the AWD property from the Grace property

source area, and the remnants of the plume are attenuating.

3.1.3.2 VINYL CHLORIDE DISTRIBUTION

Vinyl chloride was detected above the Screening Value of 2 ug/L at 40 of 112 locations,

with a maximum concentration of 200 ug/L. Figure 3-5 shows the maximum vinyl chloride

concentration, regardless of depth, detected in groundwater samples collected between October

14, 2002 and November 12, 2002, the most recent Site-wide sampling round. The Screening

Value of 2 ug/L was used as the minimum contour interval on Figure 3-5. A comparison of

Figure 3-4 to Figure 3-5 shows that the vinyl chloride distribution is similar to the VDC

distribution. The distribution of vinyl chloride is less widespread than that of VDC and overall

the vinyl chloride concentrations are lower than the VDC concentrations. The similarity in the

distribution reflects the fact that vinyl chloride is a breakdown product of, and a possible less

than 0.5 parts per million impurity in, VDC.

The highest concentrations of vinyl chloride, exceeding 100 ug/1, were detected in deep

unconsolidated deposits and shallow bedrock groundwater adjacent to the southwestern edge of

the Industrial Landfill, in monitoring well clusters LF-10, LF-02, and LF-19. A vinyl chloride

concentration of 100 ug/L were also detected in a groundwater sample collected beneath the

Assabet River at ASBRV-T6.

FOR W.R. GRACE & Co. - CONN 3-4 GeoTrans, Inc. M \WP DOCS'-MW _2003\R0206l230.doc

3.1.3.3 BENZENE DISTRIBUTION

Benzene was detected above the Screening Value of 5 ug/L at 26 out of 112 locations,

with a maximum concentration of 4,500 ug/L. Figure 3-6 shows the maximum benzene

concentration, regardless of depth, detected in samples collected between October 14, 2002 and

November 12, 2002, the most recent Site-wide sampling round. The Screening Value of 5 ug/L

was used as the minimum contour interval on Figure 3-6. A comparison of Figure 3-6 to Figures

3-4 and 3-5 shows that benzene is less widely distributed than VDC and vinyl chloride. Elevated

concentrations of benzene are mainly limited to the area of the Industrial Landfill. The highest

concentrations of benzene, exceeding 1,000 ug/1, were detected in deep unconsolidated deposits

groundwater adjacent to the southeastern edge of the Industrial Landfill, in monitoring well

cluster LF-06.

There is a noticeable change in the distribution of benzene in groundwater between the

2002 annual sampling round and the 2001/2002 sampling results reported in the Draft RI Report

(GeoTrans, 2002b). Benzene was not detected above the Screening Value of 5 ug/L in the

northeast portion of the Site beneath the BOC Gases property.

3.1.3.4 DISTRIBUTION OF OTHER VOCs

As indicated in Table 3-1, six other VOCs were detected above their Screening Value.

These six compounds were detected above the Screening Value at seven or fewer locations and

were not widely distributed.

The compounds 1,2-dichloroethane (1,2-DCA) and 1,2-dichloropropane were each

detected above their Screening Value of 5 ug/L at seven and four locations, respectively.

Chloroethane was detected above its Screening Value of 4.6 ug/L at five locations.

Concentrations in excess of the Screening Values for these three compounds are limited to the

area downgradient of the Industrial Landfill. 1,2-DCA and chloroethane were detected above

their Screening Values in ARS extraction well ELF and in several wells in the B-08 and LF-06

monitoring well clusters. 1,2-DCA was also detected above the Screening Value in one well

each of the AR-12 and AR-21 well clusters. 1,2-dichloropropane was detected above the

Screening Value in one well in each of the AR-12, AR-21, and B-08 well clusters, as well as

extraction well ELF.

FOR W.R GRACE & Co. - CONN 3-5 GeoTrans, Inc. M WP [XX S N099 20031R02061230doc

Methylene chloride was detected above its Screening Value of 5 ug/L at two out of 112

locations. Methylene chloride was detected above the Screening Value in one well in each of the

B-08 and LF-06 well clusters, which are located downgradient of the Industrial Landfill.

Chloroform was detected above its Screening Value of 5 ug/L at one out of 112 locations.

Chloroform was detected above the Screening Value in LF-11BR, which is located downgradient

of the Industrial Landfill. Chloroform has not been detected in this well during previous sampling

rounds.

Trichloroethene (TCE) was detected above the Screening Value of 5 ug/L at two

locations. TCE was detected above the Screening Value in one well of the PT-11 cluster and in

monitoring well PT-09. These wells are located south of Muskrat and Turtle Ponds, adjacent to

the Assabet River. The PT-11 well cluster is located on the south side of the Assabet River.

These compounds are not detected above the Screening Value in groundwater on the Grace

property. A review of groundwater quality data south of the Assabet River, included in Section

5.4 of the Phase 1 RI Data Report Addendum (GeoTrans, 2002a), indicates that these compounds

are likely emanating from VOC sources located south of the Assabet River, and they are

unrelated to the Grace Site.

3.1.3.5 GROUNDWATER QUALITY TRENDS

An evaluation of recent groundwater concentration trends was done using the Mann-

Kendall Trend Test for Small Sample Sizes ("Trend Test") (US EPA, 2000). The Trend Test was

done for the three most prevalent compounds at the Site, VDC, vinyl chloride, and benzene,

using data collected from 1998 through 2002. The Trend Test was done to provide a statistical

evaluation of the recent trends in groundwater quality.

The Trend Test was used to identify whether there is a statistically significant upward

trend or downward trend in water quality at a 95 percent confidence level. The trend is

determined by computing the difference between the concentrations of a particular compound

detected in a well each year. The number of positive differences minus the number of negative

differences is the statistic "S". The value of S is compared to Table A-l 1 in the US EPA

guidance document (US EPA, 2000) to determine if there is a statistically significant increasing

trend, decreasing trend, or no trend in the data set. The Trend Test requires a minimum of four

samples collected at regular time intervals, with no duplicate concentrations and no missed

FOR W.R GRACE & Co. - CONN 3-6 GeoTrans, Inc. MAVVP DOC'S N09

sampling events. Therefore, this analysis was done only on wells that were sampled each year

beginning in 1998. A value of one half the detection limit was used for non-detect results. If one

compound was not detected in two or more years from 1998 to 2002 for a certain well, the

compound was eliminated from the analysis of that well because the data do not conform to the

requirements of the analysis. The Trend Test for small sample sizes is described in "Guidance for

Data Quality Assessment, Practical Methods for Data Analysis" (US EPA, 2000).

Table 3-2 summarizes the results of the Trend Test. The table indicates, for wells in

which the data were sufficient to perform the statistical analysis, whether there is a downward,

upward, or no trend in the VDC, vinyl chloride, or benzene concentration since 1998. For wells

in which a trend was identified, the range of concentration change is indicated, with the first

number indicating the concentration detected in 1998 and the second number indicating the

concentration detected in 2002.

The Trend Test for VDC concentrations was done using data from 50 wells. Sixteen

wells were identified as having downward VDC concentration trends and three wells were

identified as having upward trends. The downward trend in several wells represented a relatively

large decrease in VDC concentration. The VDC concentration in unconsolidated deposits wells

LF-10A and LF-10B, located on the southwestern side of the Industrial Landfill, decreased from

330 to 110 ug/L, and from 220 to 85 ug/L, respectively. The VDC concentration in shallow

bedrock wells MW-06B and MW-07B, located on the BOC Gases property, decreased from 390

to 185 ug/L and 250 to 100 ug/L, respectively.

VDC concentrations have increased in three monitoring wells located downgradient of the

Industrial Landfill. In shallow bedrock well LF-02A VDC concentrations have increased from

75 ug/L in 1998 to 230 ug/L in 2002. VDC concentrations in shallow unconsolidated deposits

well LF-13B have increased from 2.6 in 1998 to 19 ug/L in 2002. VDC concentrations in

shallow unconsolidated deposits well AR-20A have increased slightly from 9.7 to 18 ug/L.

The Trend Test for vinyl chloride concentrations was done using data from 44 wells.

Thirteen wells were identified as having downward vinyl chloride concentration trends and two

wells were identified as having upward trends. The downward trend in several wells represented

a relatively large decrease in vinyl chloride concentration. The vinyl chloride concentration in

deep unconsolidated deposits well LF-11BR, located adjacent to the former Secondary Lagoon,

FOR W.R. GRACE & Co. - CONN 3-7 GeoTrans, Inc. M \WP DOCS'NOW 2003^02061230 doc

decreased from 130 ug/L to non-detect, and concentrations in deep unconsolidated deposits well

LF-10A, located adjacent to the southwestern side of the Industrial Landfill, decreased from 61 to

25 ug/L. The vinyl chloride concentration in shallow bedrock well MW-07B, located on the

BOC Gases property, decreased from 43 to 10 ug/L.

Vinyl chloride concentrations have increased in two monitoring wells. Vinyl chloride

concentrations in shallow bedrock well LF-02A, located at the southwestern edge of the

Industrial Landfill, have increased from 81 ug/L in 1998 to 200 ug/L in 2002. Vinyl chloride

concentrations in shallow unconsolidated deposits well OS A-16, located adjacent to the former

Secondary Lagoon, have increased slightly from 14 to 25 ug/L.

The Trend Test for benzene concentrations was done using data from 44 wells. Fifteen

wells were identified as having downward benzene concentration trends and two wells were

identified as having upward concentration trends. The largest downward benzene concentration

trends were observed in monitoring wells located adjacent to and downgradient of the eastern

edge of the Industrial Landfill. This is the area where the highest benzene concentrations are

detected at the Site. Benzene concentrations in three shallow unconsolidated deposits wells,

B-08B3, B-08C, and B-08D have decreased from 3,400 to 51 ug/L, from 300 to 8.7 ug/L, and

from 1,030 to 2.6 ug/L, respectively. Benzene concentrations in shallow unconsolidated

deposits wells LF-06C and LF-15 have decreased from 6,400 to 4,300 ug/L and from 39.5 to less

than 1 ug/L, respectively. Benzene concentrations in bedrock wells LF-06 and LF-06N have

decreased from 140 to 31 ug/L and from 1,200 to 650 ug/L, respectively. Benzene

concentrations in AR-21 have decreased from 180 to 2.4 ug/L.

Benzene concentrations have increased slightly in two monitoring wells. Benzene

concentrations in deep unconsolidated deposits well OSA-16B, located adjacent to the former

Secondary Lagoon, have increased slightly from 8.95 ug/L in 1998 to 13 ug/L in 2002. Benzene

concentrations in shallow bedrock well OSA-03BR, located adjacent to the Former Slowdown

Pit, have increased slightly from 0.71 in 1998 to 2.4 ug/L in 2002.

To put the long-term groundwater quality trends into perspective, the distribution of VDC

in groundwater, drawn using data collected prior to 1984, is included as Figure 3-7. A

comparison of Figure 3-7 to Figure 3-4 shows that, Site-wide, VDC concentrations were

considerably higher in 1984 than in 2002. The maximum VDC concentration detected in the

FOR W.R. GRACE & Co. - CONN 3-8 GeoTrans, Inc. M \WP DOCS \099 2003 R0206I230 doc

1984 time frame was 2,900 ug/L, while the maximum concentration detected in the fall of 2002

was 570 ug/L. As shown on Figure 3-7, the area containing the highest VDC concentrations,

greater than 300 ug/L, was much more extensive in the 1984 time frame, extending beneath the

former Slowdown Pit to the south beneath a portion of the Industrial Landfill, Sinking Pond, the

Agway/Kress property and partially beneath Muskrat Pond. As shown on Figure 3-4, the area

containing the highest VDC concentrations, greater than 300 ug/L, in the fall of 2002, is limited

to a few monitoring wells located adjacent to and immediately south of the Industrial Landfill. In

addition, while there were no monitoring wells located northeast of the Grace property in the

1984 time frame, data collected by others between 1984 and 1987 indicate that VDC was likely

present in groundwater at elevated concentrations in this area by 1984.

3.2 INORGANIC COMPOUND SAMPLING

Groundwater samples were collected from 12 locations for inorganic compound analysis

and from four locations for general chemistry analysis. The inorganic compound samples were

collected from monitoring wells located downgradient of the ARS capture zone toward the

Assabet and School Street wellfields. These wells were selected to provide information on the

inorganic compound concentrations in the vicinity of the wellfields. The general chemistry

samples were collected to provide additional information on the water chemistry of the

background wells. Groundwater sampling was done according to the procedures outlined in the

FSP (HSI GeoTrans, 2000). The results of the inorganic compound analyses are included in

Tables A-4 and A-5.

Table 3-3 lists inorganic compounds detected in groundwater since October 2002. The

following are listed in the table for each compound:

• The Screening Value;

• The number of locations in which the compound was detected above the Screening Value;

• The total number of locations for which the compound was analyzed;

• The number of samples in which the compound was detected at concentrations above the Screening Value;

FOR W.R. GRACE & Co. - CONN 3-9 GeoTrans, Inc. M ^\VP [XK S NOW 2003 vR0206!230 doc

• The total number of samples for which the compound was analyzed;

• The number of samples in which the compound was detected; and

• The maximum detected concentration.

Compounds detected above the Screening Value are marked with an asterisk on the right

side of the table and Screening Values that are based on the PRO are marked with a number

symbol. Details regarding the basis for the Screening Values can be found in Section 3.2 of the

Draft RI Report (GeoTrans, 2002b).

As discussed below, the results indicate that inorganic compound concentrations in

groundwater near the Assabet and School Street wellfields are similar to data from previous

samples. As indicated in Table 3-3, between 12 and 16 locations were sampled for each inorganic

compound since October 2002. A total of 16 inorganic compounds were detected in the samples

analyzed for inorganic compounds. Not every compound was detected in every well. Of the 16

inorganic compounds detected, four were detected above their Screening Value. Nine

compounds, aluminum, barium, cadmium, chromium, cobalt, copper, thallium, vanadium, and

zinc, were detected at concentrations below their Screening Value. Three of the compounds,

calcium, magnesium, and potassium, do not have Screening Values. These three compounds are

commonly abundant in groundwater.

Manganese and iron were detected above their Screening Values at twelve and ten of 16

locations, respectively. While manganese and iron concentrations at most locations were similar

to concentrations observed in previous samples there were a few exceptions. Manganese

concentrations in monitoring wells AR-29D and AR-31S were below the Screening Value while

previous samples from those locations were above the Screening Value. Manganese

concentrations in monitoring wells AR-30SBR and AR-31SBR were above the Screening Value

while previous samples from those locations were below it. Iron concentrations in monitoring

well AR-31 SBR were above the Screening Value while previous samples from that location were

below it. As indicated in Section 3.5.3 of the Draft RI Report (GeoTrans, 2002b), the widespread

distribution of manganese and iron in groundwater suggests that concentrations above the

Screening Values of these compounds result primarily from natural conditions, rather than Site

operations. In fact, the naturally occurring background concentrations of manganese and iron for

most areas of the Site are above the Screening Values (GeoTrans, 2002b). While much of the

FOR W.R. GRACE & Co. - CONN 3-10 GeoTrans, Inc. M.\WP DOCS NOW 2IX>3'R0206l230.doc

iron and manganese that is detected in groundwater above Screening Values is likely naturally

occurring, Site data suggests that local geochemical conditions associated with Site activities in

the area downgradient of the Industrial Landfill and near the former source areas, have resulted in

increased solubility of naturally occurring manganese and iron.

Sodium was detected above the Screening Value at seven of 16 locations. Observed

sodium concentrations are within a reasonable range for groundwater in New England.

Arsenic was detected above its Screening Value at one of 16 locations. Arsenic was

detected in shallow bedrock well AR-26SBR at concentrations ranging between 15.6 and

27.1 ug/L. Arsenic was not detected in groundwater from this well in 2001.

FOR W.R. GRACE & Co. - CONN 3-11 GeoTrans, Inc. M:\WP DOCS-NOW 2()03'R0206I230 doc

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Table 3-2. Results of Mann-Kendall Trend Test for small sample size

Vinyl Vinyl Chloride Chloride

Location VDC TREND VDC Range TREND Range BenzeneTREND Benzene Range

AR-03B1 NONE NONE NONE AR-09A DOWNWARD 41-4.9 NONE NONE

AR-09BR DOWNWARD 35-6.6 NONE NONE AR-11B1 NONE NONE NONE AR-11B2 NONE NONE NONE

AR-16ADP NONE NONE DOWNWARD 3.6-0.58 AR-20 NONE NONE DOWNWARD 3.6-2.3

AR-20A UPWARD 9.7-18 NONE AR-21 DOWNWARD ND-ND DOWNWARD 180-2.4

AR-21A DOWNWARD 11-6.3 DOWNWARD 12-1.3 NONE AR-22 NONE

AR-25B DOWNWARD 20-2.1 DOWNWARD 15-3.2 NONE ASSABET1 NONE

B-06B5 NONE B-08A NONE NONE B-08B NONE

B-08B3 DOWNWARD 3400-51 B-08C NONE DOWNWARD 300-8.7 B-08D DOWNWARD 1030-2.6

CLF-2A DOWNWARD 14-2.1 DOWNWARD 2.6-0.71 ELF NONE NONE NONE

G-3A NONE NONE NONE G-3BR NONE LF-02A UPWARD 75-230 UPWARD 81-200 NONE LF-05E NONE NONE NONE LF-06 NONE DOWNWARD 140-31

LF-06C DOWNWARD 6400-4300 LF-06N DOWNWARD 1200-650 LF-10 NONE NONE NONE

LF-10A DOWNWARD 330-110 DOWNWARD 61-25 NONE LF-10B DOWNWARD 220-85 NONE DOWNWARD 11-4.8

LF-11AR NONE NONE NONE LF-11BR NONE DOWNWARD 130-ND DOWNWARD 8.1-ND LF-11R DOWNWARD 5.8-2.8 DOWNWARD 20-14 NONE LF-12 DOWNWARD 2.2-ND NONE DOWNWARD 32-17

LF-12A DOWNWARD 24-1.3 LF-13A NONE DOWNWARD 8.8-4.6 DOWNWARD 4.4-1.5 LF-13B UPWARD 2.6-19 LF-13B NONE LF-15 DOWNWARD 39.5-0.73 MLF NONE NONE NONE

MW-06B DOWNWARD 390-185 DOWNWARD 19-5.15 MW-07B DOWNWARD 250-100 DOWNWARD 43-10 NONE MW-13B DOWNWARD 54-16 NONE NONE

NLGP NONE NONE OSA-01A DOWNWARD 66-27 NONE

GeoTrans, Inc. P \PROJECnWROACTON\MKanaly\2003\MKSummary2003 xls - MK Summary 2003

Table 3-2. Results of Mann-Kendall Trend Test for small sample size

Vinyl Vinyl Chloride Chloride

Location VDC TREND VDC Range TREND Range BenzeneTREND Benzene Range

OSA-01BR NONE DOWNWARD 9-ND OSA-01C NONE OSA-02A NONE

OSA-03BR NONE NONE UPWARD 071-24 OSA-05B NONE

OSA-06BR NONE NONE NONE OSA-07B NONE NONE OSA-09B DOWNWARD 32 5-8 1 DOWNWARD 155-06 OSA-11A DOWNWARD 42-48 OSA-11B NONE DOWNWARD 23-ND OSA-12B NONE NONE OSA-13B NONE OSA-16B NONE UPWARD 14-25 UPWARD 895-13 PT-03B1 NONE NONE NONE

PT-09 NONE PT-11B1 NONE

SLBR NONE NONE NONE WLF NONE NONE DOWNWARD 12-37

VDC Range is the VDC concentration detected in 1998 and the VDC concentration detected in 2002

Vinyl Chloride Range is the vinyl chloride concentration detected in 1998 and the vinyl chloride concentration detected in 2002

Benzene Range is the benzene concentration detected in 1998 and the benzene concentration detected in 2002

Concentrations in ng/L

ND is non-detect

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DOC ID: 232778 DATE: 03/28/2003 TITLE: Monitoring Program Report, 2002 DESCRIPTION: Figure 3-2: VDC, Vinyl Chloride and Benzene

Concentrations in Unconsolidated Deposits Groundwater, Fall 2002



TARGET SHEET


(X) OVERSIZED MAP

() NON-PAPER MEDIA

() OTHER:

DOC ID: 232778 DATE: 03/28/2003 TITLE: Monitoring Program Report, 2002 DESCRIPTION: Figure 3-3: VDC, Vinyl Chloride and Benzene

Concentrations in Bedrock Groundwater, Fall 2002



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, UOMTORMG WELL (»at OR OUSTER)

• EXTRACTION «D1

• PUBLIC HATER SUPPLY WELL

• PROPOSED PUBLIC WATER SUPPLY WELL

^-^ RI«R TRANSECT

VDC CONCENTRATION 2002

^^H 100 - S70 ifljA VOC

•̂ H 100-300 uqA VDC

^̂ | 10-100 uqA VDC

| | 7-10 u9A VDC

SAMPLES COLLECTED BETWEEN OCTOBER 14 AND NOVEMBER 12. 2002

VDC CONCENTRATIONS SHOWN ARE UAUUUM REGARDLESS OF DEPTH CONCENTRATION BOUNDARCS ARE APPROXIMATE

VDC - VINYUDENE CHLORIDE - I 1-OICHLOROETHENE

0 600

Seal* In feet

TITLE

Distribution of VDC in Groundwater, Fall 2002

LOCATION W.R. Grace, Acton, MA. CHECKED ACS FIGURE

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EXPLANATION

WR. GRACE PROPERTY BOUNDARY (APPROXIMATE)

MONITORHC KU. (SMOE OR CLUSTER)

• EXTRACTION HELL

PROPOSED PUBLIC WATER SUPPLY HELL

RIVER TRANSECT

VINYL CHLORIDE CONCENTRATION 2002

2-10 . CHLOMK

SAMPLES COLLECTED BETKEN OCTOBER 14 AND NOVEMBER 12. 2002

VINYl CHLORIDE CONCENTRATIONS SHOW ARE MAXMUM REGARDLESS Of DEPTH. CONCENTRATION BOUNDARIES ARE APPROXIMATE

Sc«l« In fMl

Distribution of Vinyl Chloride in Groundwater, Fall 2002

LOCATION: W.R. Grace, Acton, MA. CHECKED *£S FIGURE:

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LAWSBROOK

Groundwater Quality Data Collected By Others Between 1984-1987

EXPLANATION

MQNITORINC WELL (SMCU OR CLUSTER)

PUBLIC WATER SUPPLY WEU.

PROPOSED PUBLIC WATER SUPPLY WELL

WR GRACE PROPERTY BOUNDARY

VDC CONCENTRATION PRE-1984

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^̂ 1 100-300 u?A VOC

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VOC CONCENTRATIONS SHOWN ARE MAXKUM REGARDLESS OF DEPTH CONCENTRATION BOUNDARIES ARE APPROXMATE

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WATER QUALITY DATA FROM SAMPLES COLLECTED PRIOR TO 1984

900

Scale In fMt

TITLE

Distribution of VOC in Groundwater, Pre-1984

\ LOCATION W.R. Grace, Acton, MA. CHECKED ACS FIGURE

DRAFTED RMK

FILE IW-VOC-B.OWC 3-7 rans,inc DATE 3/26/03

4. REFERENCES

CDM, 1996. Amended Monitoring Plan- ARS Treatment System. September 18, 1996.

GeoTrans, 2002a. Phase 1 RI Data Report Addendum, August 15, 2002.

GeoTrans, 2002b. Draft Remedial Investigation Report, August 30, 2002.

HSI GeoTrans, 2000a. Field Sampling Plan, March 10, 2000.

HSI GeoTrans, 2000b. Quality Assurance Project Plan, March 10, 2000.

US EPA, 2000. Guidance for Data Quality Assessment, Practical Methods for Data Analysis, EPA/600/R-96/084.

W. R. Grace, 2002. Meeting Summary (10/8/02), October 16, 2002.

Woodard & Curran, Phase 1 Initial Site Investigation Report and Tier 1C Permit Application, Debris Area off Knox Trail, Concord, MA, MADEP RTN 3-21297, December 2002.

FOR W.R. GRACE & Co. - CONN 4-1 GeoTrans, Inc. M \WP DOCS N099 2()03'Rl)206l 230 doc

> > n as

Table A-l. VOC concentrations m groundwater, Fall 2002 LOCATION: AR-03B1 AR-09A AR-09BR A R - I 1 B 1 1 AR-11B2

DATE SAMPLED: 10 31 02 10/17/02 10 P02 10/2302 10'23 02 1 0 2 4 0 2 10/23/02 10'23 02 OPEN INTERVAL 4 to 5 (BR) 68 to 71 57 to 62 (BR) 93 to 94 101 to 102 60 to 70 (BR) 103 to in 1 1 t o 2 0 ( B R )

QATYPE: 1 1

VOCs 1, ,1-Trichloroctliane ND(1) ND(1 ) 1 N D ( 1 ) ND(1) N D ( I ) N D ( 1 ) ND(2) N D ( 1 ) 1, ,2,2-Tetractiloroethane ND(1) ND(1) ND(1) N D ( I ) ND(1) ND(1) ND(2) N D ( I ) 1, ,2-Tnchloroethane ND(1) N D ( I ) ND(1) N D ( 1 ) ND(1) N D ( 1 ) ND(2) N D ( 1 ) 1, -Dichloroethane ND(1) ND(1) ND(1) 058 J N D ( I ) 05! J 74 N D ( I ) 1, -Dichloroethene 11 4 9 J , 66J 56 9 7 N D ( I ) 34 ND(1) 1,2-Dichloroethane ND(1) ND(1 ) N D ( 1 ) ND(1) N D ( 1 ) 0 % J 53 N D ( 1 ) 1 ,2 -Dichloropropane ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( U 71 031 J 2-Butanone ND(5) ND(5) ND(5) ND(5) ND(5) 69 ND(10) 44 J 2-Hexanone ND(S) ND(5) ND(5) ND(5) ND(5) ND(S) ND(10) ND(5) 4-Methy1-2-Pentanone ND(5) ND(5) ND(5) 2 8 J ND(5) N D ( 5 ) ND(10) ND(5) Acetone ND(5) ND(5) ND(5) 3 6 J ND(5) 3 3 J 8 5 J ND(5) Benzene 065 J 2 J 2 2 J 5 39 9 5 8 68 Bromoch loromethane N D ( 1 ) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) ND(2) N D ( I ) Bromodichloromethane ND(1) NDJ1) N D ( 1 ) N D ( I ) N D ( 1 ) ND(1) ND(2) N D ( 1 ) Bromofbrm ND(1) ND(1) ND(1) ND(1) N D ( 1 ) N D ( I ) ND(2) N D ( 1 ) Bromomethane ND(1) ND(I ) ND(1) ND(1) ND(1) ND(1) ND(2) N D ( I ) Carbon Disulfide ND(1) ND(1) ND(1) ND(1) ND(1) N D ( I ) ND(2) N D ( 1 ) Carbon Tetrachlonde N D ( I ) N D ( I ) N D ( I ) ND(1) ND(1) N D ( 1 ) ND(2) N D ( I ) Chlorobenzene ND(1) ND(1) ND(1) N D ( l ) N D ( 1 ) N D ( 1 ) ND(2) N D ( 1 ) Chloroethane N D ( 1 ) ND(1) N D ( 1 ) ND(1) N D ( t ) N D ( 1 ) 4 1 N D ( 1 ) Chloroform ND(1) ND(1 ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) ND(2) N D ( l ) Chloromethane ND(1) ND(1 ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) ND(2) N D ( I ) cis-1,2 Dichloroethene ND(1) ND(1) ND(1) ND(1) N D ( I ) N D ( I ) ND(2) ND(!) cis-l,3-Dichloropropene ND(1) N D ( I ) ND(1) N D ( 1 ) N D ( 1 ) ND ( 1 ) ND(2) N D ( 1 ) Dibromochloromethane ND(1) ND(1) N D ( I ) N D ( I ) N D ( 1 ) N D ( 1 ) ND(2) N D ( I ) "'hylbenzene N D ( 1 ) ND(1) N D ( 1 ) N D ( I ) N D ( I ) N D ( 1 ) ND(2) N D ( 1 )

thyl tert buty l ether N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( l ) N D ( 1 ) ND(2) N D ( 1 ) -rvlethylene Chloride N D ( 1 ) N D ( I ) N D ( 1 > ND(1) N D ( 1 ) N D ( 1 ) 1 4J N D ( I ) Styrene ND(1) N D ( 1 ) N D ( 1 ) N D ( I ) N D ( I ) N D ( I ) N D ( 2 ) N D ( I ) Tetrachlorocthene ND(1) ND(1) ND(1) ND(1) N D ( 1 ) M ) ( l ) N D ( 2 ) ND(1) Toluene N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( I ) N D ( 2 ) 033 J lrans-1,2 Dichloroethene ND(1) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 2 ) N D ( I ) trans- 1 ,3-Dichloropropene ND(1) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 2 ) N D ( 1 ) Tnchloroethene N D ( I ) ND(1) ND(1) ND(1) N D ( I ) N D ( 1 ) ND(2) ND(1) Tnchlorofluoromethane N D ( I ) ND(1 ) ND(1) ND(1) N D ( l ) N D ( 1 ) ND(2) N D ( I ) Vinyl Acetate N D ( i ) ND(1) ND(1) ND(1) N D ( I ) ND(1) | ND(2) N D ( I ) Vinyl Chloride 055 J 88 J 9 1 ) 31 19 4 2 14 ND(1)

ND(1) ND(1) ND(1) N D ( I ) N D ( 1 ) 1 ND(2) N D ( I )

NOTES: Concentrations in u& L Open Interval elevation in feet NGV D (BR) Open Interval in bedrock DUP - Duplicate Sample ND (10) - Compound not detected at limit indicated in parentheses J - Estimated Value R Rejected

GeoTrans, Inc. P project wrgacton database\acccss2000 N099db mdb FRM PnntWQsum

Table A-l VOC concentrations in groundwater, Fall 2002 LOCATION.! AR-16ADP AR-20 AR-20A AR-21 AR-21 A AR-22 AR-25B AR-27D

DATE SAMPLED: 10/24/02 10/23/02 10/2302 10/18/02 10/18 02 11 1 02 10/16 02 10/21 '02 OPEN INTERVAL: 73 to 83 (BR) 87 to 92 (BR) 123 to 133 78 to 83 (BR) 103 to 113 106to 1 16 52 to 57 (BR) 104 to 114

QA TYPE:

VOCs

,1,1-Tnchloroethane ^ N D ( I ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ,1,2,2-Tetrachloroethane N D ( I ) N D ( 1 ) ND(1) 1 ND(1) ND(1) N D ( 1 ) ND(1) N D ( 1 ) ,1,2-Tnchloroethane ^ ND(1) ND(1) ND(1) | ND(1) ND(1) ND(1) ND(1) ND(1) ,1-Dichloroethane ^ ND(1) ND(1) ND(1) J ND(1) ' 2 0 6 8 J N D ( 1 ) N D ( 1 ) ,1-Dichloroethene 2 8 3 8 18 ND(1) 63 7 2 1 34 ,2-Dichloroethane N D ( I ) N D ( 1 ) ND(1) ND(1) 1 9 N D ( 1 ) N D ( 1 )

1,2-Dichloropropane ND(1) N D ( 1 ) t ND(1 ) 081 J 14 2 1 N D ( 1 ) N D ( 1 ) 2-Butanone ND(5) ND(5) ND (5) ND(5) ND(5) N D ( 5 ) ND(5) ND(5) 2-Hexanone ND (5) ND(5) ND(5) ND(5) ND(5) ND(5) ( ND(5) ND(5) 4-Methyl-2 Pentanone ND (5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) N D ( 5 ) Acetone ND (5) ND(5) ND(5) ND(5) ND(5) N D O ) [ ND(5) 25 Benzene 0 58 J 2 3 071 J 2 4 042 J N D ( 1 ) 1 3 058 J Bromochloromethane ND(1) N D ( 1 ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) Bromodichloromethane ND(1) ND(1) ND(1) ND(1) ND( l ) ND(1) 1 ND(1) ND(1) Bromoform f ND(1) N D ( I ) ND(1) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) Bromomethane ND(1) N D ( I ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 )

Carbon Disulfide ND(1) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) N D ( I ) N D ( 1 ) Carbon Tetrachlonde ND ( 1 ) N D ( I ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) Chlorobenzene ND(1) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) Chloroethane N D ( 1 ) N D ( 1 ) ND(1) ND(1) 1 9 N D ( 1 ) N D ( I ) N D ( 1 ) Chloroform N D ( l ) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) 1 5 Chloromethane N D ( l ) N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( l ) N D ( 1 ) cis- 1 ,2 Dichloroethene ND ( 1 ) N D ( 1 ) ND(1) j ND(1) N D ( 1 ) N D ( 1 ) N D ( I ) N D ( 1 ) cis- 1 ,3-Dichloropropene N D ( 1 ) N D ( 1 ) ND(1) ND(1) N D ( I ) N D ( 1 ) N D ( 1 ) ND(1) Dibromochloromethane ND(1) ND(1) ND(1) I ND(1) ND(1) ND(1) N D ( I ) ND(1) ""'hyl benzene N D ( 1 ) N D ( 1 ) ND(1) t N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1)

thyl tert butyl ether N D ( 1 ) N D ( 1 ) ND(1) ' N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ! ivlethylene Chloride N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( I ) ND(1) Styrene N D ( 1 ) N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1)

Tetrachloroethene ND(1) ND(1) ND(1) N D ( 1 ) ND(1) N D ( 1 ) N D ( I ) ND(1) Toluene ND(1) N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1) trans- 1 ,2-Dichloroethene ND(1) N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) trans-1 ,3-Dichloropropene ND(1) N D ( I ) ND(1 ) N D ( 1 ) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 )

Tnchloroethene ND(1) N D ( I ) ND(1) N D ( I ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 )

Tnchloronuoromethane N D ( 1 ) N D ( 1 ) ND(1) N D ( l ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1) Vinyl Acetate ND(1) ND(1) ND(1) ND(1) N D ( I ) ND(1) ND(1) N D ( I )

Vinyl Chloride 1 8 3 3 1 3 t ND(1) 1 3 N D ( 1 ) 3 2 083 J Xylenes (total) N D ( 1 ) ND(1) ND(1) ' ND(1) ND(1) ND(1) ND(1) ND(1)

NOTES: Concentrations in fig-^Open Interval elevation in feet NGVD (BR) - Open Interval in bedrock DUP Duplicate Sample ND (10) - Compound not detected at limit indicated in parentheses J Estimated Value R - Rejected

GeoTrans, Inc. P\project\wrgaclon*dalabase4)cccss2000,NO

Table A-l. VOC concentrations in groundwater, Fall 2002 LOCATION: AR-27SBR AR-28DBR AR-29D AR-29D AR-29SBR AR-30D AR-30SBR AR-3ID

D^TE SAMPLED 11/8/02 10/31/02 11/7 '02 11/7/02 11/502 1 1 602 1 1/7/02 11/1/02 O P E N I N T E R V A I : 82 to 91 (BR) 43 to 54 (BR) 91 to 101 91 to 101 5610 67 (BR) 7-. to 85 47 to 61 (BR) 82 to 92

QA TYPE: DUP

VOCs ,1,1 -Trichloroethane N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 8) ,1 ,2,2-Tetrachloroethane ND(1) ND(1) ND(1) N D ( I ) ND(1) N D ( 1 ) N D ( I ) N D ( I 8) ,1,2-Tnchloroethane ND(1) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) N D ( I ) N D ( I 8 ) ,1-Dichloroethane N D ( 1 ) 02 J N D ( 1 ) ND(1) ND(1) 2 1 1 6 N D ( 1 8) ,1-Dichloroethene 15 15 0 5 9 J 031 J 42 D 19 13 45 ,2-Dichloroethane ND(I ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 8) ,2 -Dich loropropane N D ( I ) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 ) N D ( l ) N D ( 1 ) ND(1 8)

2-Butanone ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(9) 2-Hexanone ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(9) 4-Methyl-2-Pentanone ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(9) Acetone ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(5) ND(9) Benzene ND(1) ND(1) N D ( 1 ) ND(1) 063 J 0 2 5 J N D ( 1 ) N D ( 1 8) Bromochloromethane ND(1) ND(1) N D ( 1 ) ND(1) ND(1) N D ( I ) N D ( 1 ) N D ( I 8) Bromodichloromethane N D ( 1 ) ND(1) ND(1) N D ( I ) ND(1) N D ( 1 ) ND(1) N D ( 1 8) Bromoform ND(1) ND(1) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( l 8) Bromomethane ND(1) N D ( I ) ND(1) L ND(1) ND(1) N D ( 1 ) ND(1) ND(1 8) Carbon Disulfide N D ( 1 ) N D ( t ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 8) Carbon Tetrachlonde ND(1) ND(1) ND(1) ND(1) ND(1) N D ( 1 ) ND(1) N D ( 1 8) Chlorobenzene ND(1 ) N D ( I ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( I ) N D ( 1 8) Chloroethane ND(1) N D ( I ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( l ) ND(1 8) Chloroform ND(1) N D ( l ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 8) Chloromethane N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( I ) N D ( 1 8) cis-l,2-Dichloroethene N D ( 1 ) N D ( 1 ) N D ( I ) ND(1) N D ( 1 ) 066J 054 J N D ( 1 8) cis-l,3-Dichloropropene N D ( 1 ) ND(1) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1 8) Dibromochloromethane N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) ND (1 8) "•hylbenzene N D ( 1 ) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 8)

thyl tert butyl ether ND(1) N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 ) 0 2 9 J N D ( 1 ) N D ( 1 8) Methylene Chloride N D ( 1 ) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 8) Styrene N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( I 8) Telrachloroethene ND(1) N D ( 1 ) N D ( ! ) N D ( I ) N D ( I ) N D ( I ) N D ( 1 ) N D ( I 8) Toluene ND(1) N D ( 1 ) ND(1) N D ( 1 ) 045 J N D ( I ) N D ( 1 ) ND(1 8) trans- 1 ,2-Dichloroethene ND(1) ND(1 ) ND(1) N D ( I ) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 8) trans- 1 ,3-Dichloropropene N D ( 1 ) ND(1 ) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( I ) ND(1) N D ( 1 8) Tnchloroethene N D ( 1 ) 063 J N D ( 1 ) N D ( I ) N D ( 1 ) 1 2 6 0 5 1 J Tnchlorofluoromethane ND(1) ND(1 ) N D ( I ) ND(1) ND(1) N D ( 1 ) ND(1) ND(1 8) Vinyl Acetate ND(1) ND(1 ) ND(1) ND(1) N D ( 1 ) N D ( 1 ) ND(1) ND(1 8) Vinyl Chloride N D ( 1 ) 0 3 2 J ND(1) ND( l ) 1 9 03 J 021 J 1 J Xylenes (total) N D ( I ) ND(1) ND(1) ND(1) N D ( 1 ) N D ( I ) N D ( 1 ) N D ( 1 8)

NOTES: Concentrations in ngT-Open Interval-elevation m feel N G V D (BR) Open Inlerval in bedrock DUP Duplicate Sample ND (10) Compound not detected at limit indicated m parentheses J Estimated Value R - Rejected

GeoTrans, Inc. P \projecl\wrgactondalabasc access:oOO NOWdb mdb FRM PnnlWQsum

Table A-l. VOC concentrations in groundwater, Fall 2002. LOCATION: AR-31S ASSABET1 Assabet-2A B-06B5 B-08A B-08B B-08B3 B 08C

DATE SAMPLED: 11/5/02 11/12/02 11/12/02 10/28/02 10 1402 10 14 02 10/1402 1 0 ' L 4 02 OPEN INTERVAL: 112to 122 71 to 80 98 to 106 48 to 49 (BR) ! 5 t o 2 5 ( B R ) 76 to 86 113 to 1 14 I08 to 1 1 8

QA TYPE:

VOCs

1,1,1-Tnchloroethane ND(1) 1 2 ND(1) N D ( l ) N D ( 2 6 ) ND(20) N D ( 1 3) N D ( 1 ) ,1 ,2,2-Tetrachloroethane N D ( 1 ) N D ( 1 ) ND(1) N D ( I ) N D ( 2 6 ) ND(20) ND(1 3) N D ( 1 ) ,1,2-Tnchloroethane ND(1) ND(1) ND(1) ND(1) N D ( 2 6 ) ND(20) ND(1 3) N D ( 1 ) ,1-Dichloroethane ND(1) ND(1) ND(1) ^ N D ( 1 ) 42 79 J 2 1 1 8 ,1-Dichloroethene 1 45 066J 0 6 4 J " 1 7 N D ( 2 6 ) ND (20) ND(1 3) 1 9 ,2-Dichloroelhane ND(1) N D ( 1 ) ND(1) N D ( 1 ) 100 34 15 32 ,2-Dichloropropane N D ( 1 ) ND(1) N D ( 1 ) N D ( 1 ) 96 ND(20) 1 7 0 2 J

2-Butanone ND(5) , ND (5) ND(5) ND(5 ) N D ( I 3 ) N D ( I O O ) N D ( 6 5 ) N D ( 5 ) 2-Hexanone ND(5) ND(5) ND(5) ND(5) ND(13) N D ( I O O ) ND(6 5) ND(5) 4-Methyl-2-Pentanone ND(5) ND(5) ND(5) ND(5) N D ( 1 3 ) N D ( I O O ) N D ( 6 S ) ND(5) Acetone 2 2 J ND(5) ND(5) _ 21J 100 300 30 28 J Benzene ND(1) ND(1) ND(1) ' N D ( I ) 32 810 51 87 Bromochloromethane ND(1) ND(1) N D ( 1 ) N D ( I ) N D ( 2 6 ) ND(20) ND(1 3) N D ( 1 ) Bromodichloromethane N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 2 6 ) ND(20) N D ( 1 3) N D ( 1 ) Bromoform ND(1) ND(1) ND(1) ND(1) N D ( 2 6 ) ND (20) N D ( 1 3) N D ( I ) Bromomelhane ND(1) ND(1) ND(1) 1 ND(1) N D ( 2 6 ) ND (20) ND(1 3) ND(1) Carbon Disulfide N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 2 6 ) ND (20) N D ( 1 3) 039J Carbon Tetrachlonde N D ( I ) ND(1) ND(1) ND(1) N D ( 2 6 ) ND (20) N D ( 1 3) N D ( l ) Chlorobenzene ND(1) ND(1) ND(1) ND(1) N D ( 2 6 ) ND (20) N D ( 1 3) N D ( 1 ) Chloroethane N D ( I ) ND(1) ND(1) ND(1) 14J 46 J 38 J N D ( I ) Chloroform 036J ND(1) N D ( 1 ) ND(1) N D ( 2 6 ) ND (20) N D ( 1 3) N D ( 1 ) Chloromethane ND(1) ND(1) ND(1) N D ( l ) N D ( 2 6 ) ND(20) 0 35 J ND(1) cis-l,2-Dichloroethene N D ( 1 ) ND(1) N D ( 1 ) N D ( I ) N D ( 2 6 ) ND(20) 033 J 0 2 3 J cis-l,3-Dichloropropene N D ( 1 ) ND(1) ND(1) ND(1) N D ( 2 6 ) ND(20) N D ( 1 3) N D ( 1 ) Dibromochloromethane N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 2 6 ) ND (20) N D ( 1 3) N D ( 1 ) ""•hylbenzene ND(1) N D ( ! ) ND(1) N D ( 1 ) 0 7 9 J ND(20) 18 1 8

thyl tert bu t> l ether 086J 8 5 ND(1) N D ( 1 ) N D ( 2 6 ) ND(20) N D ( 1 3) N D ( 1 ) Methylene Chloride N D ( 1 ) N D ( 1 ) ND(1) N D ( 1 ) 2 4 J 8 3 J 0 81 J N D ( 1 ) Styrene N D ( 1 ) ND(1) ND(1) N D ( 1 ) N D ( 2 6 ) ND (20) N D ( I M 024 J Tetrachloroethene N D ( 1 ) N D ( 1 ) N D ( I ) N D ( I ) N D ( 2 6 ) ND(20) N D ( 1 3) N D ( 1 ) Toluene N D ( I ) ND(1) ND(1) N D ( l ) N D ( 2 6 ) ND (20) 046 J 0 2 6 J trans-1 ,2-Dichloroethene N D ( 1 ) N D ( 1 ) ND(1) N D ( I ) N D ( 2 6 ) ND(20) N D ( 1 i) 0 4 6 J trans- 1 ,3-Dichloropropene N D ( l ) N D ( 1 ) ND(1) N D ( l ) N D ( 2 6 ) ND (20) N D ( l 3) ND(1) Trichloroethene N D ( l ) 1 ND(1) N D ( 1 ) N D ( 2 6 ) ND(20) N D ( 1 1) 0 2 4 J Tnchlorofluoromethane N D ( I ) N D ( 1 ) N D ( l ) ! ND(1) N D ( 2 6 ) ND (20) N D ( 1 3) ND(1) Vinyl Acetate ND(1) ND(1) ND(1) 1 ND(1) ND(26) ND (20) N D ( l 3) ND(1) Vinyl Chloride ND(1) ND(1) j ND(1) [ ND(1) 064J ND (20) 03 J 12J Xylenes (total) ND(1) N D ( 1 ) ND(1) i ND(1) 0 8 5 J ND(20) 1 J 0 6 6 J

NOTES: Concentrations in n&L Open Interval elevation in feet NGVD (BR) Open Interval in bedrock DUP - Duplicate Sample ND (10) Compound not detected at limit indicated in parentheses J - Estimated Value R Rejected

GeoTrans, Inc. P \projcct wrgacton dalabase\acccss2000 NC»9db mdb FRM_PnntWQsum

Table A-l. VOC concentrations in groundwater, Fall 2002. LOCATION: B-08D B-09B4 1RISTOFFERSC CLF-2A ELF G-3A G-3BR LAWSBROOK

DATE SAMPLED: 10/14/02 1 1/5/02 11/12/02 103002 1031 02 102902 10 2902 11/12/02 OPEN INTERVAL: 125 to 140 13 to 14 (BR) 86 to 96 84 to 89 97 to 137 43 to 51 10 to 20 (BR) 108 to 118

QATYPE:

VOCs

,1,1-Tnchloroethane N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 1 ) N D ( 2 4 ) N D ( I ) N D ( 1 ) N D ( l ) ,1 ,2,2-Tetrachloroethane ND(1) ND(1) N D ( I ) N D ( 1 ) ND (2 4) N D ( 1 ) N D ( 1 ) ND(1) ,1,2-Tnchloroethane ND(1) ND(1) N D ( I ) | N D ( 1 ) ND (2 4) N D ( 1 ) N D ( 1 ) ND(1) ,1-Dichloroethane ND(1) ND(1) ND(1) N D ( 1 ) 39 N D ( 1 ) N D ( 1 ) ND(1 ) ,1-Dichloroethene ND(1) 1 9 028 J 2 I 19 0 9 9 J N D ( 1 ) 99 ,2-Dichloroethane 032 J ND(1) N D ( 1 ) N D ( I ) 84 N D ( 1 ) N D ( 1 ) N D ( 1 ) ,2-Dichloropropane N D ( 1 ) ND(1) ND(1) N D ( 1 ) 89 N D ( 1 ) N D ( 1 ) N D ( 1 )

2-Butanone ND(5) ND(5) ND(5) N D ( 5 ) ND(12) ND(5 ) ND(S) ND_(5) 2-Hexanone ND(5) ND(5) ND(5) ND(5) N D ( 1 2 ) N D ( S ) ND(5) ND(5) 4-MethyI-2-Pentanone ND(5) ND(5) ND(5) ND(5) ND(12) ND(5) ND(5) ND(5) Acetone 3 8 J ND(5) ND(5) ND(5) 10J N D ( 5 ) ND(5) ND(5J^ Benzene 26 ND(1) ND(1) ND(1) 41 1 4 99 ND(I) Bromochloromethane ND(1) N D ( 1 ) ND(1) N D ( 1 ) ND (2 4) N D ( 1 ) N D ( 1 ) ND(1) Bromodichloromethane N D ( I ) ND(1) N D ( i ) N D ( 1 ) ND (2 4) N D ( 1 ) N D ( l ) N D ( 1 ) Bromoform ND(1) N D ( I ) N D ( I ) ND(1) ND (2 4) N D ( 1 ) N D ( 1 ) ND(1) ~ Bromomethane ND(1) ND(1) ND(1) ND(1) ND (2 4) N D ( 1 ) N D ( I ) ND(1) Carbon Bisulfide ND(1) ND(1) ND(1) N D ( I ) ND (2 4) N D ( 1 ) ND(1) ND(1) Carbon Tetrachlonde N D ( 1 ) ND(1) ND(1) N D ( 1 ) ND (2 4) N D ( l ) N D ( 1 ) N D ( 1 ) Chlorobenzene N D ( 1 ) ND(1) ND(1) ND(1) ND (2 4) N D ( t ) N D ( 1 ) N D ( 1 ) Chloroethane 06 J ND(1) ND(1) N D ( 1 ) 92 N D ( 1 ) N D ( 1 ) N D ( 1 ) Chloroform N D ( 1 ) ND(1) ND(1) ND(1) ND (2 4) N D ( 1 ) N D ( 1 ) N D (

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