130 Research Lane Suite 2 Guelph Ontario Canada N1G 5G3

PH 5198222230 FAX 5198223151

wwwgeosynteccom

August 23 2012

Gerardo Millaacuten-Ramos Site Assessment ManagerRemedial Project Manager Office of Site Remediation and Restoration Region I EPA 5 Post Office Square Suite 100 Boston Massachusetts 02109-3946

Re Response to EPArsquos Request for a Background Study of Arsenic Concentrations in Site Soils Within the Former Recreational Areas Somersworth Sanitary Landfill Superfund Site Somersworth New Hampshire

Dear Mr Millaacuten-Ramos

On behalf of the Work Settling Defendants (WSDs) for the Somersworth Sanitary Landfill Superfund Site (the ldquoSiterdquo) Geosyntec Consultants (Geosyntec) is responding to an e-mail from the Environmental Protection Agency (EPA) dated May 24 2012 requesting a geologist attest that the lithology of samples identified for use to establish background concentrations of arsenic are representative of native soils Geosyntec submitted a letter to EPA on May 7 2012 providing historical analytical data from the Site that indicates naturally-occurring arsenic concentrations in the vicinity of the Site are consistent with or greater than the arsenic concentrations observed in the July 2011 landfill cover soil samples

The attached memorandum from one of Geosyntecrsquos geologists licensed in New Hampshire details which data the EPA specifically directed Geosyntec to review within the two provided historical documents and the subsequent findings The overall conclusion of the review is that arsenic concentrations detected in the July 2011 test pits collected by Geosyntec which range between 66 and 163 mgkg are within the site-specific native soils arsenic concentrations as represented by the OB-7U discrete native soil samples collected in 1989 These data ranged from non-detect (ND) where the reporting limit was not provided to 49 mgkg

As previously discussed the following three lines of evidence indicate that the landfill cover concentrations are attributable to naturally occurring arsenic in soils

1 The soil samples collected in July 2011 from the landfill cover test pit investigation are consistent with the composition of arsenic-bearing glacial till found in the Somersworth area and there is no evidence to support that arsenic in the soil samples are from an anthropogenic source (as noted by a professional geologist in a memorandum submitted to EPA on January 9 2012)

Mr Gerardo Millaacuten-Ramos Page 2 of 2 August 23 2012

2 Concentrations of arsenic in the landfill cover soil samples are consistent with statewide background concentrations

3 Historical samples identified in the attached memorandum are representative of native soils and concentrations of arsenic in the landfill cover soil samples are below site-specific background concentrations encountered in these native soils from the Site

Please let us know if you have any additional questions or comments

Sincerely

Cherilyn Mertes MSc Thomas A Krug MSc PEng Project Manager Associate

Attachments Memorandum re Distribution of Arsenic Soils at Somersworth Landfill Somersworth New Hampshire

cc Andrew Hoffman NHDES Tom Willis City of Somersworth Robert Belmore City of Somersworth Dave West General Electric Company

289 Great Road Suite 105 Acton Massachusetts 01720

PH 9782639588 FAX 9782639594

wwwgeosynteccom

Memorandum

Date 23 August 2012

To

From

Thomas Krug Geosyntec Consultants

Cherilyn Mertes MSc and Erin Kirby NH PG 736

Subject Distribution of Arsenic in Soils at Somersworth Landfill Somersworth New Hampshire

Background

On May 7 2012 Geosyntec Consultants (Geosyntec) submitted to the Environmental Protection Agency (EPA) a letter providing historical arsenic data from soils at the Somersworth Sanitary Landfill (the Site) to provide EPA-requested site-specific data for naturally-occurring background concentrations of arsenic In an e-mail dated May 24 2012 EPA requested that a New Hampshire professional geologist ldquoattest that the lithology of the background samples comports to the lithology of native soilsrdquo In telephone discussions EPA advised Geosyntec that additional historical soil boring locations upgradient and transgradient of the landfill should be used The locations that were identified by EPA for Geosyntec to establish background arsenic data at the Site were B-1 B-4 B-5 B-7 B-12 (GZA 1989) and OB-7U (Canonie 1992) shown in Figure 1 The historical arsenic concentrations for these locations are provided in Table 1

To conduct this evaluation Geosyntec reviewed Volume I Remedial Investigation Somersworth New Hampshire (RI Report) prepared by Goldberg-Zoino amp Associates Inc (GZA) of Manchester New Hampshire and Wehran Engineers and Scientists of Methuen Massachusetts dated May 1989 and the RI Data Gathering Report Somersworth Landfill Somersworth New Hampshirerdquo prepared by Canonie Environmental dated May 1992 The GZA RI Report details site assessment activities that include soil sampling and arsenic analytical data that Geosyntec at EPArsquos direction used to establish background conditions at the Somersworth Landfill Superfund Site in Somersworth New Hampshire Based on the boring logs provided in the RI Report GZA advanced the five soils borings reviewed to depths ranging from 315 feet below ground surface (ft bgs) to 107 ft bgs B-1L (405 ft bgs) B-4L (315 ft bgs) B-5R (892 ft bgs) B-7R (1070 ft bgs) and B-12R (510 ft bgs) in June 1985 and October 1986 GZA collected discrete soil samples at five-foot intervals at each soil boring location with a 1 38-inch inner diameter split-spoon sampler driven to 24 inches with a 140-pound hammer GZA visually classified and logged the soil samples using the Burmister classification system selected soil samples were submitted for arsenic laboratory analysis Boring logs are provided in Attachment A

Geosyntec also reviewed an additional soil boring log and arsenic analytical results from OB-7U included in the RI Data Gathering Report Canonie 1992 which was logged by JW Billiard dated 10 October 1989 Based on the boring log the OB-7U soil boring was advanced to 40 ft bgs Soil samples were collected at five discrete two-foot depth intervals 0-2 ft bgs 4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 2

Laboratory Analytical Data

Composite Sampling

Between 1985 and 1986 GZA submitted seven composite soil samples from each of the five soil borings reviewed B-1 B-4 B-5 B-7 and B-12 for metals laboratory analysis Laboratory results are presented in Table I23 (provided as an attachment to this document) of the RI Report for antimony arsenic barium beryllium cadmium chromium copper lead mercury nickel selenium silver thallium zinc and total cyanide Soil samples were submitted to either GZArsquos laboratory in Newton Massachusetts or Eastern Analytical Inc in Concord New Hampshire A duplicate soil samples was submitted from soil boring location B-1 In addition two soil samples were also submitted from soil boring B-7 The report does not specify if the second sample is from a different location however the correlation of the two B-7 soil sample metals analytical results is suggestive of another duplicate sample

Geosyntec compared the laboratory results from the composite soil samples to New Hampshire Department of Environmental Services (NHDES) Soil Remediation Criteria Arsenic was reported in all seven of the composite soil samples where three of the seven composite soil samples exceeded the applicable criterion of 11 milligrams per kilogram (mgkg) The average concentration of arsenic in five composite soil samples (Geosyntec used the average arsenic concentration from the two B-1 and the two B-7 soil samples) is 17 mgkg with concentrations ranging between 80 mgkg (B-7) and 37 mgkg (B-4)

Discrete Sampling

Based on Table 6 of Canonie 1992 soil boring location OB-7U was advanced in 1989 A total of six soil samples were collected from the following depth intervals 0-2 ft bgs 4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs These six soil samples were submitted to a laboratory for arsenic analysis Based on depth interval information provided in Table 6 Geosyntec interprets the soil samples as discrete not composite soil samples

Arsenic was reported in five of the six OB-7U soil samples exceeding the NHDES soil criterion of 11 mgkg However the arsenic results from the soil sample collected from the 0-2 ft bgs depth interval which was reportedly 62 mgkg was not included in our background analysis because based on its depth interval and the fact that the soil sample was collected from adjacent to the baseball field (see Figure 21) it is possible the soil represents fill material not native soil Based on the five Canonie 1992 data intervals interpreted as in situ (4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs) the arsenic concentrations are non-linear where there is no correlation between depth and arsenic concentration (ie it does not increase or decrease with depth) The average concentration of arsenic in the remaining five discrete in situ soil samples is 243 mgkg with concentrations ranging between non-detect (no reporting limit provided) at the 22-24 ft bgs interval to 49 mgkg at the 4-6 ft bgs interval

Lithological Data

After reviewing the boring logs identified by the EPA Geosyntec interprets the first three to five feet material is generally classified as fine sand and silt that may or may not be non-native fill Underlying the possible fill material from approximately 5 ft to between 20 to 70 ft bgs GZA

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 3

identified the underlying unit as native stratified sand and silts where Billiard (Canonie 1992) identified the unit as till Based on the lithological descriptions the sand unit generally fines with depth where gravel is identified as between trace to over 50 of the sand unit In B-1L B-4L B-5R and OB-7U clay is encountered at the base of this unit Weathered bedrock was encountered between approximately 20 ft bgs to 70 ft bgs As Geosyntec previously stated in our 05 December 2011 memorandum till is a stratified mixture comprised predominantly of silt to pebble size particles which is consistent with the in situ material described in the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U)

Conclusions

Based on a 1998 study commissioned by the NHDES to establish background metals concentrations in New Hampshire it was concluded that soils from the southeastern portion of the State of New Hampshire as defined as the area east of Concord to Somersworth may exhibit elevated concentrations of arsenic (SHA 1998) This statement is confirmed by more recent research that has demonstrated that naturally-occurring arsenic concentrations in glacial deposits of the New England Coastal Basin have been documented to be greater than the NHDES standard of 11 mgkg (deLemos et al 2006 Kiemowitz et al 2005 Stollenwork and Colman 2004 Robinson and Ayotte 2007) The observed site-specific native overburden lithology based on the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U) is consistent with the glacial deposits of the New England Coastal Basin Arsenic concentrations from the composited soils samples from these locations ranged from 8 to 37 mgkg and 4 of the 7 composite soil samples that were representative of native soils reported arsenic concentrations that were equal to or greater than the NHDES standard of 11 mgkg Arsenic concentrations from the 7 depth-discrete samples at OB-7U ranged from non-detect to 62 mgkg with 5 of the 6 samples having reported arsenic concentrations greater than or equal to the NHDES standards Also the seven composite soil samples and 8 depth-discrete samples that Geosyntec is interpreting as representative of site-specific native soil arsenic concentrations were consistent with or greater than the concentrations observed in the landfill cover test-pitting conducted on July 6 2011 The range of arsenic concentrations detected in the July 2011 test pit collected by Geosyntec fall within the range of arsenic concentrations reported in site-specific native soils represented by the OB-7U discrete native soil samples ND to 49 mgkg

References

Boudette et al ldquoHigh Levels of Arsenic in the Groundwaters of Southeastern New Hampshire A Geochemical Reconnaissancerdquo United States Department of Interior Geological Survey Open-File Report 85-202 1985

Canonie 1992 ldquoRI Data Gathering Report Somersworth Landfill Somersworth New Hamsphirerdquo May 1992deLemos et al ldquoLandfill-Stimulated Iron Reduction and Arsenic Release at the Coakley Superfund Site (NH)rdquo Environ Sci Technol 2006 40(1) 67-73

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 4

Goldberg-Zoino amp Associates Inc (GZA) and Wehran Engineers and Scientists (Wehran) 1989 ldquoVolume I Remedial Investigation Somersworth New Hampshirerdquo May 1989 Keimowitz et al ldquoNaturally Occurring Arsenic Mobilization at a Landfill in Maine and Implications for Remediationrdquo Applied Geochemistry 20 (2005) 1985-2002

Robinson G R and Ayotte J D 2007 ldquoRock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New Englandrdquo US Department of the Interior US Geological Society Open-File Report 2007-1119

Sanborn Head amp Associates Inc (SHA) 1998 ldquoBackground Metals Concentration Study New Hampshire Soils New Hampshire Department of Environmental Services Concord New Hampshirerdquo File 1571 November 1998

Stollenwerk K G and Coleman J A 2004 ldquoNatural Remediation of Arsenic Contaminated Ground Water Associated with Landfill Leachaterdquo US Department of the Interior US Geological Survey Fact Sheet 2004-3025 May 2004

Attachments

Table 1 Figure 1 Table I23 Attachment 1 ndash Boring Logs

Arsenic in Soils Memo_20120823

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

289 Great Road Suite 105 Acton Massachusetts 01720

PH 9782639588 FAX 9782639594

wwwgeosynteccom

Memorandum

Date 23 August 2012

To

From

Thomas Krug Geosyntec Consultants

Cherilyn Mertes MSc and Erin Kirby NH PG 736

Subject Distribution of Arsenic in Soils at Somersworth Landfill Somersworth New Hampshire

Background

On May 7 2012 Geosyntec Consultants (Geosyntec) submitted to the Environmental Protection Agency (EPA) a letter providing historical arsenic data from soils at the Somersworth Sanitary Landfill (the Site) to provide EPA-requested site-specific data for naturally-occurring background concentrations of arsenic In an e-mail dated May 24 2012 EPA requested that a New Hampshire professional geologist ldquoattest that the lithology of the background samples comports to the lithology of native soilsrdquo In telephone discussions EPA advised Geosyntec that additional historical soil boring locations upgradient and transgradient of the landfill should be used The locations that were identified by EPA for Geosyntec to establish background arsenic data at the Site were B-1 B-4 B-5 B-7 B-12 (GZA 1989) and OB-7U (Canonie 1992) shown in Figure 1 The historical arsenic concentrations for these locations are provided in Table 1

To conduct this evaluation Geosyntec reviewed Volume I Remedial Investigation Somersworth New Hampshire (RI Report) prepared by Goldberg-Zoino amp Associates Inc (GZA) of Manchester New Hampshire and Wehran Engineers and Scientists of Methuen Massachusetts dated May 1989 and the RI Data Gathering Report Somersworth Landfill Somersworth New Hampshirerdquo prepared by Canonie Environmental dated May 1992 The GZA RI Report details site assessment activities that include soil sampling and arsenic analytical data that Geosyntec at EPArsquos direction used to establish background conditions at the Somersworth Landfill Superfund Site in Somersworth New Hampshire Based on the boring logs provided in the RI Report GZA advanced the five soils borings reviewed to depths ranging from 315 feet below ground surface (ft bgs) to 107 ft bgs B-1L (405 ft bgs) B-4L (315 ft bgs) B-5R (892 ft bgs) B-7R (1070 ft bgs) and B-12R (510 ft bgs) in June 1985 and October 1986 GZA collected discrete soil samples at five-foot intervals at each soil boring location with a 1 38-inch inner diameter split-spoon sampler driven to 24 inches with a 140-pound hammer GZA visually classified and logged the soil samples using the Burmister classification system selected soil samples were submitted for arsenic laboratory analysis Boring logs are provided in Attachment A

Geosyntec also reviewed an additional soil boring log and arsenic analytical results from OB-7U included in the RI Data Gathering Report Canonie 1992 which was logged by JW Billiard dated 10 October 1989 Based on the boring log the OB-7U soil boring was advanced to 40 ft bgs Soil samples were collected at five discrete two-foot depth intervals 0-2 ft bgs 4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 2

Laboratory Analytical Data

Composite Sampling

Between 1985 and 1986 GZA submitted seven composite soil samples from each of the five soil borings reviewed B-1 B-4 B-5 B-7 and B-12 for metals laboratory analysis Laboratory results are presented in Table I23 (provided as an attachment to this document) of the RI Report for antimony arsenic barium beryllium cadmium chromium copper lead mercury nickel selenium silver thallium zinc and total cyanide Soil samples were submitted to either GZArsquos laboratory in Newton Massachusetts or Eastern Analytical Inc in Concord New Hampshire A duplicate soil samples was submitted from soil boring location B-1 In addition two soil samples were also submitted from soil boring B-7 The report does not specify if the second sample is from a different location however the correlation of the two B-7 soil sample metals analytical results is suggestive of another duplicate sample

Geosyntec compared the laboratory results from the composite soil samples to New Hampshire Department of Environmental Services (NHDES) Soil Remediation Criteria Arsenic was reported in all seven of the composite soil samples where three of the seven composite soil samples exceeded the applicable criterion of 11 milligrams per kilogram (mgkg) The average concentration of arsenic in five composite soil samples (Geosyntec used the average arsenic concentration from the two B-1 and the two B-7 soil samples) is 17 mgkg with concentrations ranging between 80 mgkg (B-7) and 37 mgkg (B-4)

Discrete Sampling

Based on Table 6 of Canonie 1992 soil boring location OB-7U was advanced in 1989 A total of six soil samples were collected from the following depth intervals 0-2 ft bgs 4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs These six soil samples were submitted to a laboratory for arsenic analysis Based on depth interval information provided in Table 6 Geosyntec interprets the soil samples as discrete not composite soil samples

Arsenic was reported in five of the six OB-7U soil samples exceeding the NHDES soil criterion of 11 mgkg However the arsenic results from the soil sample collected from the 0-2 ft bgs depth interval which was reportedly 62 mgkg was not included in our background analysis because based on its depth interval and the fact that the soil sample was collected from adjacent to the baseball field (see Figure 21) it is possible the soil represents fill material not native soil Based on the five Canonie 1992 data intervals interpreted as in situ (4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs) the arsenic concentrations are non-linear where there is no correlation between depth and arsenic concentration (ie it does not increase or decrease with depth) The average concentration of arsenic in the remaining five discrete in situ soil samples is 243 mgkg with concentrations ranging between non-detect (no reporting limit provided) at the 22-24 ft bgs interval to 49 mgkg at the 4-6 ft bgs interval

Lithological Data

After reviewing the boring logs identified by the EPA Geosyntec interprets the first three to five feet material is generally classified as fine sand and silt that may or may not be non-native fill Underlying the possible fill material from approximately 5 ft to between 20 to 70 ft bgs GZA

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 3

identified the underlying unit as native stratified sand and silts where Billiard (Canonie 1992) identified the unit as till Based on the lithological descriptions the sand unit generally fines with depth where gravel is identified as between trace to over 50 of the sand unit In B-1L B-4L B-5R and OB-7U clay is encountered at the base of this unit Weathered bedrock was encountered between approximately 20 ft bgs to 70 ft bgs As Geosyntec previously stated in our 05 December 2011 memorandum till is a stratified mixture comprised predominantly of silt to pebble size particles which is consistent with the in situ material described in the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U)

Conclusions

Based on a 1998 study commissioned by the NHDES to establish background metals concentrations in New Hampshire it was concluded that soils from the southeastern portion of the State of New Hampshire as defined as the area east of Concord to Somersworth may exhibit elevated concentrations of arsenic (SHA 1998) This statement is confirmed by more recent research that has demonstrated that naturally-occurring arsenic concentrations in glacial deposits of the New England Coastal Basin have been documented to be greater than the NHDES standard of 11 mgkg (deLemos et al 2006 Kiemowitz et al 2005 Stollenwork and Colman 2004 Robinson and Ayotte 2007) The observed site-specific native overburden lithology based on the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U) is consistent with the glacial deposits of the New England Coastal Basin Arsenic concentrations from the composited soils samples from these locations ranged from 8 to 37 mgkg and 4 of the 7 composite soil samples that were representative of native soils reported arsenic concentrations that were equal to or greater than the NHDES standard of 11 mgkg Arsenic concentrations from the 7 depth-discrete samples at OB-7U ranged from non-detect to 62 mgkg with 5 of the 6 samples having reported arsenic concentrations greater than or equal to the NHDES standards Also the seven composite soil samples and 8 depth-discrete samples that Geosyntec is interpreting as representative of site-specific native soil arsenic concentrations were consistent with or greater than the concentrations observed in the landfill cover test-pitting conducted on July 6 2011 The range of arsenic concentrations detected in the July 2011 test pit collected by Geosyntec fall within the range of arsenic concentrations reported in site-specific native soils represented by the OB-7U discrete native soil samples ND to 49 mgkg

References

Boudette et al ldquoHigh Levels of Arsenic in the Groundwaters of Southeastern New Hampshire A Geochemical Reconnaissancerdquo United States Department of Interior Geological Survey Open-File Report 85-202 1985

Canonie 1992 ldquoRI Data Gathering Report Somersworth Landfill Somersworth New Hamsphirerdquo May 1992deLemos et al ldquoLandfill-Stimulated Iron Reduction and Arsenic Release at the Coakley Superfund Site (NH)rdquo Environ Sci Technol 2006 40(1) 67-73

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 4

Goldberg-Zoino amp Associates Inc (GZA) and Wehran Engineers and Scientists (Wehran) 1989 ldquoVolume I Remedial Investigation Somersworth New Hampshirerdquo May 1989 Keimowitz et al ldquoNaturally Occurring Arsenic Mobilization at a Landfill in Maine and Implications for Remediationrdquo Applied Geochemistry 20 (2005) 1985-2002

Robinson G R and Ayotte J D 2007 ldquoRock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New Englandrdquo US Department of the Interior US Geological Society Open-File Report 2007-1119

Sanborn Head amp Associates Inc (SHA) 1998 ldquoBackground Metals Concentration Study New Hampshire Soils New Hampshire Department of Environmental Services Concord New Hampshirerdquo File 1571 November 1998

Stollenwerk K G and Coleman J A 2004 ldquoNatural Remediation of Arsenic Contaminated Ground Water Associated with Landfill Leachaterdquo US Department of the Interior US Geological Survey Fact Sheet 2004-3025 May 2004

Attachments

Table 1 Figure 1 Table I23 Attachment 1 ndash Boring Logs

Arsenic in Soils Memo_20120823

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 2

Laboratory Analytical Data

Composite Sampling

Between 1985 and 1986 GZA submitted seven composite soil samples from each of the five soil borings reviewed B-1 B-4 B-5 B-7 and B-12 for metals laboratory analysis Laboratory results are presented in Table I23 (provided as an attachment to this document) of the RI Report for antimony arsenic barium beryllium cadmium chromium copper lead mercury nickel selenium silver thallium zinc and total cyanide Soil samples were submitted to either GZArsquos laboratory in Newton Massachusetts or Eastern Analytical Inc in Concord New Hampshire A duplicate soil samples was submitted from soil boring location B-1 In addition two soil samples were also submitted from soil boring B-7 The report does not specify if the second sample is from a different location however the correlation of the two B-7 soil sample metals analytical results is suggestive of another duplicate sample

Geosyntec compared the laboratory results from the composite soil samples to New Hampshire Department of Environmental Services (NHDES) Soil Remediation Criteria Arsenic was reported in all seven of the composite soil samples where three of the seven composite soil samples exceeded the applicable criterion of 11 milligrams per kilogram (mgkg) The average concentration of arsenic in five composite soil samples (Geosyntec used the average arsenic concentration from the two B-1 and the two B-7 soil samples) is 17 mgkg with concentrations ranging between 80 mgkg (B-7) and 37 mgkg (B-4)

Discrete Sampling

Based on Table 6 of Canonie 1992 soil boring location OB-7U was advanced in 1989 A total of six soil samples were collected from the following depth intervals 0-2 ft bgs 4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs These six soil samples were submitted to a laboratory for arsenic analysis Based on depth interval information provided in Table 6 Geosyntec interprets the soil samples as discrete not composite soil samples

Arsenic was reported in five of the six OB-7U soil samples exceeding the NHDES soil criterion of 11 mgkg However the arsenic results from the soil sample collected from the 0-2 ft bgs depth interval which was reportedly 62 mgkg was not included in our background analysis because based on its depth interval and the fact that the soil sample was collected from adjacent to the baseball field (see Figure 21) it is possible the soil represents fill material not native soil Based on the five Canonie 1992 data intervals interpreted as in situ (4-6 ft bgs 12-14 ft bgs 22-24 ft bgs 30-32 ft bgs and 36-38 ft bgs) the arsenic concentrations are non-linear where there is no correlation between depth and arsenic concentration (ie it does not increase or decrease with depth) The average concentration of arsenic in the remaining five discrete in situ soil samples is 243 mgkg with concentrations ranging between non-detect (no reporting limit provided) at the 22-24 ft bgs interval to 49 mgkg at the 4-6 ft bgs interval

Lithological Data

After reviewing the boring logs identified by the EPA Geosyntec interprets the first three to five feet material is generally classified as fine sand and silt that may or may not be non-native fill Underlying the possible fill material from approximately 5 ft to between 20 to 70 ft bgs GZA

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 3

identified the underlying unit as native stratified sand and silts where Billiard (Canonie 1992) identified the unit as till Based on the lithological descriptions the sand unit generally fines with depth where gravel is identified as between trace to over 50 of the sand unit In B-1L B-4L B-5R and OB-7U clay is encountered at the base of this unit Weathered bedrock was encountered between approximately 20 ft bgs to 70 ft bgs As Geosyntec previously stated in our 05 December 2011 memorandum till is a stratified mixture comprised predominantly of silt to pebble size particles which is consistent with the in situ material described in the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U)

Conclusions

Based on a 1998 study commissioned by the NHDES to establish background metals concentrations in New Hampshire it was concluded that soils from the southeastern portion of the State of New Hampshire as defined as the area east of Concord to Somersworth may exhibit elevated concentrations of arsenic (SHA 1998) This statement is confirmed by more recent research that has demonstrated that naturally-occurring arsenic concentrations in glacial deposits of the New England Coastal Basin have been documented to be greater than the NHDES standard of 11 mgkg (deLemos et al 2006 Kiemowitz et al 2005 Stollenwork and Colman 2004 Robinson and Ayotte 2007) The observed site-specific native overburden lithology based on the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U) is consistent with the glacial deposits of the New England Coastal Basin Arsenic concentrations from the composited soils samples from these locations ranged from 8 to 37 mgkg and 4 of the 7 composite soil samples that were representative of native soils reported arsenic concentrations that were equal to or greater than the NHDES standard of 11 mgkg Arsenic concentrations from the 7 depth-discrete samples at OB-7U ranged from non-detect to 62 mgkg with 5 of the 6 samples having reported arsenic concentrations greater than or equal to the NHDES standards Also the seven composite soil samples and 8 depth-discrete samples that Geosyntec is interpreting as representative of site-specific native soil arsenic concentrations were consistent with or greater than the concentrations observed in the landfill cover test-pitting conducted on July 6 2011 The range of arsenic concentrations detected in the July 2011 test pit collected by Geosyntec fall within the range of arsenic concentrations reported in site-specific native soils represented by the OB-7U discrete native soil samples ND to 49 mgkg

References

Boudette et al ldquoHigh Levels of Arsenic in the Groundwaters of Southeastern New Hampshire A Geochemical Reconnaissancerdquo United States Department of Interior Geological Survey Open-File Report 85-202 1985

Canonie 1992 ldquoRI Data Gathering Report Somersworth Landfill Somersworth New Hamsphirerdquo May 1992deLemos et al ldquoLandfill-Stimulated Iron Reduction and Arsenic Release at the Coakley Superfund Site (NH)rdquo Environ Sci Technol 2006 40(1) 67-73

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 4

Goldberg-Zoino amp Associates Inc (GZA) and Wehran Engineers and Scientists (Wehran) 1989 ldquoVolume I Remedial Investigation Somersworth New Hampshirerdquo May 1989 Keimowitz et al ldquoNaturally Occurring Arsenic Mobilization at a Landfill in Maine and Implications for Remediationrdquo Applied Geochemistry 20 (2005) 1985-2002

Robinson G R and Ayotte J D 2007 ldquoRock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New Englandrdquo US Department of the Interior US Geological Society Open-File Report 2007-1119

Sanborn Head amp Associates Inc (SHA) 1998 ldquoBackground Metals Concentration Study New Hampshire Soils New Hampshire Department of Environmental Services Concord New Hampshirerdquo File 1571 November 1998

Stollenwerk K G and Coleman J A 2004 ldquoNatural Remediation of Arsenic Contaminated Ground Water Associated with Landfill Leachaterdquo US Department of the Interior US Geological Survey Fact Sheet 2004-3025 May 2004

Attachments

Table 1 Figure 1 Table I23 Attachment 1 ndash Boring Logs

Arsenic in Soils Memo_20120823

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 3

identified the underlying unit as native stratified sand and silts where Billiard (Canonie 1992) identified the unit as till Based on the lithological descriptions the sand unit generally fines with depth where gravel is identified as between trace to over 50 of the sand unit In B-1L B-4L B-5R and OB-7U clay is encountered at the base of this unit Weathered bedrock was encountered between approximately 20 ft bgs to 70 ft bgs As Geosyntec previously stated in our 05 December 2011 memorandum till is a stratified mixture comprised predominantly of silt to pebble size particles which is consistent with the in situ material described in the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U)

Conclusions

Based on a 1998 study commissioned by the NHDES to establish background metals concentrations in New Hampshire it was concluded that soils from the southeastern portion of the State of New Hampshire as defined as the area east of Concord to Somersworth may exhibit elevated concentrations of arsenic (SHA 1998) This statement is confirmed by more recent research that has demonstrated that naturally-occurring arsenic concentrations in glacial deposits of the New England Coastal Basin have been documented to be greater than the NHDES standard of 11 mgkg (deLemos et al 2006 Kiemowitz et al 2005 Stollenwork and Colman 2004 Robinson and Ayotte 2007) The observed site-specific native overburden lithology based on the reviewed boring logs (B-1L B-4L B-5R B-7R B-12R and OB-7U) is consistent with the glacial deposits of the New England Coastal Basin Arsenic concentrations from the composited soils samples from these locations ranged from 8 to 37 mgkg and 4 of the 7 composite soil samples that were representative of native soils reported arsenic concentrations that were equal to or greater than the NHDES standard of 11 mgkg Arsenic concentrations from the 7 depth-discrete samples at OB-7U ranged from non-detect to 62 mgkg with 5 of the 6 samples having reported arsenic concentrations greater than or equal to the NHDES standards Also the seven composite soil samples and 8 depth-discrete samples that Geosyntec is interpreting as representative of site-specific native soil arsenic concentrations were consistent with or greater than the concentrations observed in the landfill cover test-pitting conducted on July 6 2011 The range of arsenic concentrations detected in the July 2011 test pit collected by Geosyntec fall within the range of arsenic concentrations reported in site-specific native soils represented by the OB-7U discrete native soil samples ND to 49 mgkg

References

Boudette et al ldquoHigh Levels of Arsenic in the Groundwaters of Southeastern New Hampshire A Geochemical Reconnaissancerdquo United States Department of Interior Geological Survey Open-File Report 85-202 1985

Canonie 1992 ldquoRI Data Gathering Report Somersworth Landfill Somersworth New Hamsphirerdquo May 1992deLemos et al ldquoLandfill-Stimulated Iron Reduction and Arsenic Release at the Coakley Superfund Site (NH)rdquo Environ Sci Technol 2006 40(1) 67-73

Arsenic in Soils Memo_20120823

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 4

Goldberg-Zoino amp Associates Inc (GZA) and Wehran Engineers and Scientists (Wehran) 1989 ldquoVolume I Remedial Investigation Somersworth New Hampshirerdquo May 1989 Keimowitz et al ldquoNaturally Occurring Arsenic Mobilization at a Landfill in Maine and Implications for Remediationrdquo Applied Geochemistry 20 (2005) 1985-2002

Robinson G R and Ayotte J D 2007 ldquoRock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New Englandrdquo US Department of the Interior US Geological Society Open-File Report 2007-1119

Sanborn Head amp Associates Inc (SHA) 1998 ldquoBackground Metals Concentration Study New Hampshire Soils New Hampshire Department of Environmental Services Concord New Hampshirerdquo File 1571 November 1998

Stollenwerk K G and Coleman J A 2004 ldquoNatural Remediation of Arsenic Contaminated Ground Water Associated with Landfill Leachaterdquo US Department of the Interior US Geological Survey Fact Sheet 2004-3025 May 2004

Attachments

Table 1 Figure 1 Table I23 Attachment 1 ndash Boring Logs

Arsenic in Soils Memo_20120823

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

Distribution of Arsenic in Soils at Somersworth Landfill 23 August 2012 Page 4

Goldberg-Zoino amp Associates Inc (GZA) and Wehran Engineers and Scientists (Wehran) 1989 ldquoVolume I Remedial Investigation Somersworth New Hampshirerdquo May 1989 Keimowitz et al ldquoNaturally Occurring Arsenic Mobilization at a Landfill in Maine and Implications for Remediationrdquo Applied Geochemistry 20 (2005) 1985-2002

Robinson G R and Ayotte J D 2007 ldquoRock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New Englandrdquo US Department of the Interior US Geological Society Open-File Report 2007-1119

Sanborn Head amp Associates Inc (SHA) 1998 ldquoBackground Metals Concentration Study New Hampshire Soils New Hampshire Department of Environmental Services Concord New Hampshirerdquo File 1571 November 1998

Stollenwerk K G and Coleman J A 2004 ldquoNatural Remediation of Arsenic Contaminated Ground Water Associated with Landfill Leachaterdquo US Department of the Interior US Geological Survey Fact Sheet 2004-3025 May 2004

Attachments

Table 1 Figure 1 Table I23 Attachment 1 ndash Boring Logs

Arsenic in Soils Memo_20120823

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

Geosyntec Consultants

TABLE 1 ARSENIC CONCENTRATIONS IN HISTORICAL BACKGROUND SOIL SAMPLES

Somersworth Sanitary Landfill Somersworth NH

Location Date Depth (ft bgs) Arsenic

Concentration (mgkg)

Source

B-1 6251985 composite 11 Wehran 1989 Table I23

B-1 (Dup) 6251985 composite 26 Wehran 1989 Table I23

B-4 6141985 composite 37 Wehran 1989 Table I23

B-5 6141985 composite 98 Wehran 1989 Table I23 B-7 6141985 composite 8 Wehran 1989 Table I23

B-7 (Dup) 6141985 composite 84 Wehran 1989 Table I23 B-12 10151986 composite 12 Wehran 1989 Table I23

OB-7U NS 0-2 62 Canonie 1992 Table 6

OB-7U NS 4-6 49 Canonie 1992 Table 6

OB-7U NS 12-14 11 Canonie 1992 Table 6

OB-7U NS 22-24 ND Canonie 1992 Table 6

OB-7U NS 30-32 21 Canonie 1992 Table 6

OB-7U NS 36-38 16 Canonie 1992 Table 6

Acronyms Dup Duplicate Sample

ft bgs feet below ground surface mgkg milligrams per kilogram

ND not detected NS not specified

TR0237A Historical Somersworth As Data_20120528 DRAFT Table 1

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

Brook

Marsh

Peters

B-7L B-7R

B-1L

Pat

h P

P

RJ

Pro

ject

sT

R00

57S

omer

swo

rth

IIS

omer

swo

rthD

atab

aseamp

GIS

GIS

Som

ersw

orth

_Bac

kgro

und

_Me

tals

mxd

Legend

Monitoring Well

Soil Gas Collection Trench

Permeable Cover Installed in 2001 1

B-4L

Fence Line

Property Line

Waste

Surface Water

B-5R B-5U B-5L

OB-7R OB-7U

B-12L B-12R

290 145 0 290 Feet

Background Metal Sampling Locations

Somersworth Landfill Superfund Site Somersworth NH

Figure

July 2012 Guelph 1

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U

• Memo Attachmentspdf
• • Borehole Logspdf
  • • B-1L
    • B-4L
    • B-5R
    • B-5Rb
    • B-7r
    • B-7rb
    • B-7rc
    • B-12r
    • B-12rb
    • OB-7U