Office of Solid Waste and EPA-542-R-13-001
Emergency Response January 2013
(5102G) www.epa.gov/tio
www.clu-in.org/optimization
Optimization Review
Groveland Wells Numbers 1 and 2 Superfund Site
Town of Groveland, Essex County, Massachusetts
SDMS Doc ID 530604
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OPTIMIZATION REVIEW
GROVELAND WELLS NUMBERS 1 AND 2 SUPERFUND SITE
TOWN OF GROVELAND, ESSEX COUNTY, MASSACHUSETTS
Report of the Optimization Review
Site Visit Conducted at the Groveland Wells Numbers 1 and 2 Superfund Site on
February 29, 2012
FINAL REPORT
January 7, 2013
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EXECUTIVE SUMMARY
Optimization Background
U.S. Environmental Protection Agency's definition of optimization is as follows
"Efforts at any phase of the removal or remedial response to identify and implement specific actions that
improve the effectiveness and cost-efficiency of that phase. Such actions may also improve the remedy's
protectiveness and long-term implementation which may facilitate progress towards site completion. To
identify these opportunities, regions may use a systematic site review by a team of independent technical
experts, apply techniques or principles from Green Remediation or Triad, or apply other approaches to
identify opportunities for greater efficiency and effectiveness. " '
An optimization review considers the goals of the remedy, available site data, conceptual site model
(CSM), remedy performance, protectiveness, cost-effectiveness and closure strategy. A strong interest in
sustainability has also developed in the private sector and within Federal, State and Municipal
governments. Consistent with this interest, optimization now routinely considers green remediation and
environmental footprint reduction during optimization reviews. An optimization review includes
reviewing site documents, interviewing site stakeholders, potentially visiting the site for one day and
compiling a report that includes recommendations in the following categories:
• Protectiveness
• Cost-effectiveness
• Technical improvement
• Site closure
• Environmental footprint reduction
The recommendations are intended to help the site team identify opportunities for improvements in these
areas. In many cases, further analysis of a recommendation, beyond that provided in this report, may be
needed prior to implementation of the recommendation. Note that the recommendations are based on an
independent review, and represent the opinions of the optimization review team. These recommendations
do not constitute requirements for future action, but rather are provided for consideration by the Region
and other site stakeholders. Also note that while the recommendations may provide some details to
consider during implementation, the recommendations are not meant to replace other, more
comprehensive, planning documents such as work plans, sampling plans and quality assurance project
plans (QAPP).
Site-Specific Background
The Groveland Wells Nos. 1 and 2 Superfund Site is located within the Town of Groveland, Essex
County, Massachusetts within the watershed of the Merrimack River. The site consists of two operable
units (OU):
1 U.S. Environmental Protection Agency (EPA). 2012 Memorandum: Transmittal of the National Strategy to Expand
Superfund Optimization Practices from Site Assessment to Site Completion. From: James E. Woolford, Director
Office of Superfund Remediation and Technology Innovation. To: Superfund National Policy Managers (Regions 1
- 10). Office of Solid Waste and Emergency Response (OSWER) 9200.3-75. September 28, 2012.
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• Source Control operable unit (OU 2), which is limited to the original release area and the
immediately surrounding property; and
• Management of Migration operable unit (OU 1), which encompasses an approximately 850-acre
study area including the aquifer that recharges the Groveland Municipal Well Stations Nos. 1 and
2, which were impacted by site contaminants.
OU2 is located at 64 Washington Street and is commonly referred to as the "Valley property" or
"Valley/GRC property" because the contaminants of concern were released from the former Valley
Manufactured Products Company (Valley), located on property owned and formerly operated by the
Groveland Resources Corporation (GRC). Valley and GRC both formerly operated metals and plastic
parts manufacturing businesses in a building on the property. The building was abandoned when the
owner and operator went bankrupt. Both GRC and Valley are Responsible Parties (RPs). Chlorinated
solvents and cutting oils were released at the property on numerous occasions in prior years, including
surface releases, leakage from underground storage tanks (UST) and discharges to subsurface disposal
systems located at the Valley facility. Previous subsurface studies determined that the releases from
Valley caused the contamination of groundwater extracted by the Town of Groveland's public water
supply wells Nos. 1 and 2.
Summary of Conceptual Site Model
The Valley property overlies the shoulder of a local bedrock high that is overlain by approximately 30
feet (ft) of unsaturated overburden and 10 ft of saturated overburden. Releases of trichloroethene (TCE) at
the Valley property caused soil and groundwater concentrations indicative of the presence of non-aqueous
phase liquid (NAPL) in unsaturated zone and the thin saturated overburden in the southeastern portion of
the Valley property. Due to the relatively thin saturated zone of contamination in the source area and
mixing with regional groundwater flow, concentrations of TCE approximately 500 ft downgradient of the
source area were approximately a half order of magnitude lower (6,600 micrograms per liter (ng/L) at
extraction well EW-S5 compared to 40,000 ng/L at extraction well EW-S2) prior to operation of the
current pump and treat (P&T) operation.
During approximately 10 years of P&T operation the TCE concentrations in groundwater in the source
area P&T wells (EW-S1, EW-S2, and EW-S3) remained orders of magnitude above the maximum
contaminant levels (MCL), suggesting a continuing source of groundwater contamination. By contrast,
TCE concentrations in groundwater at the next set of downgradient P&T wells (EW-S4 and EW-S5)
decreased by a factor of approximately 30 within 2 years and were near or below MCLs within 8 years.
Due to a relatively steep hydraulic gradient (approximately 0.06 ft per ft) between the source area and
P&T wells EW-S4/EW-S5, and a high hydraulic conductivity, the groundwater flow velocity is relatively
fast, and TCE concentrations in this area change over the course of a few months as a result of remedial
activities.
The recently implemented in situ thermal treatment (ISTT) remedy in the source area removed the
majority of mass and has reduced TCE concentrations in soil and groundwater near the source area
accordingly. However, TCE concentrations in confirmation soil samples are nearly 2 orders of magnitude
higher than the site-specific soil cleanup standard for TCE, and suggest that contamination is still present
in vadose zone soil that has the potential to result in TCE groundwater contamination at concentrations
orders of magnitude above MCLs. The August 2011 TCE concentration of 78 ng/L in monitoring well
RW-05 (based on the most recent round of sampling at that location available to the optimization review
team), further suggests the potential that a source of groundwater contamination remains in this area. It is
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unclear, however, whether these observed soil and groundwater concentrations are isolated and of
insufficient mass to serve as the source for an extensive TCE plume above MCLs, or whether they merit
further attention.
Summary of Findings or Conceptual Model Highlights
The following findings are some of the key findings discussed in Sections 4.0 and 5.0 of the report:
• Due to 10 years of P&T operation, the plume extent has been significantly reduced to the source
area and the 500 ft of aquifer immediately downgradient of the source area.
• Due to ISTT operation, the majority of source area contamination has been removed and the TCE
concentrations in groundwater have been substantially reduced.
• Although the TCE concentrations in confirmation soil samples CSB-10 and CSB-12 were above
the soil clean up level established for the site, these results may be isolated and of insufficient
mass to serve as the source for an extensive TCE plume above MCLs (see Sections 4.1 and 4.2.1
for detailed discussion).
• Based on data from newly installed bedrock monitoring wells and monitoring of existing bedrock
monitoring and extraction wells, NAPL did not appear to enter bedrock. Furthermore,
remediation of the overburden with ISTT has significantly reduced dissolved TCE concentrations
in bedrock groundwater.
Summary of Recommendations
Recommendations are provided to improve remedy effectiveness and assist with accelerating site closure.
Recommendations to reduce costs and for technical improvement were not provided given the focus on
site closure. The recommendations in these areas are as follows:
Improving effectiveness - The optimization review team recommends continued operation of specific
extraction wells (EW-S1 through EW-S4) and treatment with the existing system for up to 1 year.
Currently EW-S4 is operating and wells EW-S1 through EW-S3 will be re-started in the near future now
that temperatures have mostly recovered from the effects of ISTT remediation. Operation of other
extraction wells is not recommended. The optimization review team recommends more frequent (i.e.,
monthly) sampling and analysis of groundwater from select wells in and downgradient of the source area,
for up to 1 year, to improve the understanding of site conditions following the ISTT remedy. As P&T
operation is currently planned, the recommended P&T for up to 1 year does not impact estimated costs for
the next year. The more frequent monitoring will add approximately $20,000 in cost. However, these
recommendations are intended to provide data that will shorten the time frame for active remediation and
ultimately result in net cost savings, as described in the following paragraph. An alternative approach that
does not include operation of extraction wells EW-S1 through EW-S3, and a discussion of the advantages
and disadvantages of that alternative approach, is presented in Section 6.1.2.
Reducing cost - The optimization review team has not provided specific recommendations for reducing
costs for operating the P&T system in its current form (for example, treatment plant upgrades) because
continued P&T operation for more than one year (at most) is considered unlikely. However, the
recommendations described above (i.e., extraction for up to 1 year with monthly monitoring) are
anticipated to result in one of several potential outcomes that will lower long-term costs relative to the
in
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current P&T system. Possible outcomes and associated estimates for potential costs savings include:
• A likely potential outcome is that P&T operation at this site will be terminated within 1 year (and
perhaps much less than 1 year). If that occurs, the current cost of $345,600 per year would likely
be reduced to approximately $65,000 per year (for project management and groundwater
monitoring). Thus, cost would be reduced by approximately $280,000 per year for this scenario
versus the current P&T system.
• Another potential outcome is that P&T extraction can be limited to source area wells EW-S1
through EW-S3 within 1 year, and the lower overall system flow rate would allow for a simpler
treatment approach. The current cost of $345,600 per year would likely be reduced to
approximately $115,000 per year (for project management, extraction/treatment, and groundwater
monitoring). Thus, cost would be reduced by approximately $230,000 per year for this scenario
versus the current P&T system. It is expected that treatment plant modifications for this scenario
would require up-front costs of approximately $50,000, with payback achieved in much less than
1 year.
• Another potential outcome is that additional source area remediation (likely to consist of
excavation and disposal) may be required in a targeted area to allow for the complete shutdown of
P&T operations. Based on the size of the targeted area, the up-front costs might range from less
than $100,000 to $500,000 or more. These up-front costs would be offset by annual savings of
approximately $280,000 per year that would result from complete termination of P&T operations
(as discussed above). Thus, the payback period might range from less than 1 year to as much as
several years for this scenario.
For these potential outcomes, the current treatment system would not be operated in its current form for
more than 1 year (and perhaps much less than 1 year). Therefore, the optimization review team
recommends that any currently planned upgrades to the P&T system be delayed if at all possible. Any
such upgrades that can ultimately be avoided, by delaying the upgrades until the treatment plant is
eliminated, would result in additional costs savings (not quantified by the optimization review team).
Technical improvement - None provided.
Site closure - The optimization review team recommends that the site team develop P&T shutdown
criteria for the remaining extraction wells and consider remedial options for the source area if P&T
shutdown criteria will not be met in the near future. A decision framework in the form of a flowchart has
been provided (see Figure 6-1) to illustrate how decisions on terminating the P&T activities and or
conducting additional investigation and remediation of the source area can be made based on data
collected over the next year (in conjunction with the P&T shutdown criteria).
Green remediation - Given the focus on site closure (i.e., the expectation that the current P&T system
will only operate for a short period of time), no opportunities for footprint reduction regarding the current
P&T system (for example, treatment plant upgrades) were contemplated. However, to the extent P&T
operations are terminated or significantly scaled back within 1 year or less, remedy footprints will be
reduced accordingly. The actual footprint reductions will depend on which of the potential outcomes on
the decision flowchart actually occurs (i.e., similar to the potential cost savings).
IV
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NOTICE
Work described herein including preparation of this report was performed by Tetra Tech for the U.S.
Environmental Protection Agency under Work Assignment 2-58 of EPA contract EP-W-07-078 with
Tetra Tech EM, Inc., Chicago, Illinois. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
v
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PREFACE
This report was prepared as part of a national strategy to expand Superfund optimization from remedial
investigation to site completion implemented by the United States Environmental Protection Agency
(EPA) Office of Superfund Remediation and Technology Innovation (OSRTI)2. The project contacts are
as follows:
Organization
Key Contact
Contact Information
EPA Office of Superfund
Remediation and Technology
Innovation
(OSRTI)
Kathy Yager
EPA
Technology Innovation and Field Services
Division (TIFSD)
11 Technology Drive (ECA/OEME)
North Chelmsford, MA 01863
yager.kathleen@epa.gov
phone:617-918-8362
Tetra Tech EM, Inc.
(Contractor to EPA)
Jody Edwards, P.O.
Tetra Tech EM Inc.
1881 Campus Commons Drive, Suite 200
Reston,VA20191
jody.edwards@tetratech.com
phone: 802-288-9485
Tetra Tech GEO
(Subcontractor to Tetra Tech EM,
Inc.)
Doug Sutton, PhD,
P.E.
Tetra Tech GEO
2 Paragon Way
Freehold, NJ 07728
doug.sutton@tetratech.com
phone: 732-409-0344
U.S. Environmental Protection Agency (EPA). 2012. Memorandum: Transmittal of the National Strategy to Expand Superfund
Optimization Practices from Site Assessment to Site Completion. From: James. E. Woolford, Director Office of Superfund
Remediation and Technology Innovation. To: Superfund National Policy Managers (Regions 1 - 10). Office of Solid Waste and
Emergency Response (OSWER) 9200.3-75. September 28,2012.
VI
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LIST OF ACRONYMS
(ig/kg micrograms per kilogram
(ig/L micrograms per liter
(ig/m3 micrograms per cubic meter
ARARs applicable or relevant and appropriate requirements
AWQC Ambient Water Quality Criteria
bgs below ground surface
BMP best management practice
CERCLA Comprehensive Environmental Response, Compensation, and Liability
Act
cis-1,2-DCE cis-1,2-dichloroethene
COC chemical of concern
COPC chemical of potential concern
CSM conceptual site model
DPT direct-push technology
EPA United States Environmental Protection Agency
ERH electrical resistance heating
ESD Explanation of Significant Difference
FEMA Federal Emergency Management Agency
foe fraction of organic carbon
FS feasibility study
ft feet
ft2 feet squared
ft3 cubic feet
GAC granular activated carbon
GETS groundwater extraction and treatment system
gpm gallons per minute
GRC Groveland Resources Corporation
GWTF groundwater treatment facility
HP Horsepower
HRSC high-resolution site characterization
Hz Hertz
ISCO In situ chemical oxidation
ISTT In situ thermal treatment
K hydraulic conductivity
Kd partitioning coefficient
Koc organic carbon partitioning coefficient
kW kilowatt
kWh kilowatt hours
L/kg liters per kilogram
L/mg liters per milligram
LTM long term monitoring
vn
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MassDEP
MCL
mg/kg
mg/L
MOM
MW
NAPL
NPL
OSRTI
OSWER
OU
P&T
PDB
PCE
PID
PRP
PVC
QA
QA/QC
QAPP
RA
RAO
RI
ROD
RSE
SC
SVE
TCE
UST
UVOx
VFD
VI
VOC
Massachusetts Department of Environmental Protection
maximum contaminant limit
milligrams per kilogram
milligrams per liter
Management of Migration
monitoring well
non-aqueous phase liquid
National Priorities List
Office of Superfund Remediation and Technology Innovation
Office of Solid Waste and Emergency Response
operable unit
pump and treat
passive diffusion bag
tetrachloroethylene (perchloroethylene)
photoionization detector
Potentially Responsible Party
polyvinyl chloride
quality assurance
quality assurance/quality control
Quality Assurance Project Plan
Remedial Action
remedial action objective
remedial investigation
Record of Decision
remedial system evaluation
source control
soil vapor extraction
Trichloroethylene
underground storage tank
ultraviolet oxidation
variable frequency drive
vapor intrusion
volatile organic compound
Vlll
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TABLE OF CONTENTS
EXECUTIVE SUMMARY i
NOTICE v
PREFACE vi
LIST OF ACRONYMS vii
TABLE OF CONTENTS ix
1.0 INTRODUCTION 1
1.1 PURPOSE 1
1.2 TEAM COMPOSITION 2
1.3 DOCUMENTS REVIEWED 3
1.4 QUALITY ASSURANCE 3
1.5 PERSONS CONTACTED 4
2.0 SITE BACKGROUND 5
2.1 LOCATION 5
2.2 SITE HISTORY 5
2.2.1 HISTORIC LAND USE AND OPERATIONS 5
2.2.2 CHRONOLOGY OF ENFORCEMENT AND REMEDIAL ACTIVITIES 6
2.3 POTENTIAL HUMAN AND ECOLOGICAL RECEPTORS 8
2.4 EXISTING DATA AND INFORMATION 8
2.4.1 SOURCES OF CONTAMINATION 9
2.4.2 GEOLOGY SETTING AND HYDROGEOLOGY 9
2.4.3 GROUNDWATER CONTAMINATION 10
2.4.4 SOIL CONTAMINATION 10
2.4.5 SEDIMENT AND SURFACE WATER CONTAMINATION 11
3.0 DESCRIPTION OF PLANNED OR EXISTING REMEDIES 12
3.1 REMEDY AND REMEDY COMPONENTS 12
3.1.1 FORMER SVE SYSTEM 12
3.1.2 P&T SYSTEM 12
3.1.3 ISTT REMEDIATION IN THE SOURCE AREA 14
3.2 RAOs AND STANDARDS 14
3.2.1 REMEDIAL ACTION OBJECTIVES FOR GROUNDWATER 15
3.2.2 CLEANUP STANDARDS FOR GROUNDWATER AND SOIL 15
3.2.3 STANDARDS FOR TREATMENT PLANT 18
3.3 PERFORMANCE MONITORING PROGRAMS 19
4.0 CONCEPTUAL SITE MODEL 21
4.1 CSM OVERVIEW 21
4.2 CSM DETAILS AND EXPLANATION 22
4.2.1 POTENTIAL IMPACT OF SOIL CONTAMINATION ON GROUNDWATER 22
4.2.2 DATA GAPS 23
4.3 IMPLICATIONS FOR REMEDIAL STRATEGY 23
IX
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5.0 FINDINGS 24
5.1 SOURCES 24
5.2 GROUNDWATER 24
5.2.1 PLUME DELINEATION 24
5.2.2 PLUME CAPTURE 24
5.2.3 GROUNDWATER CONTAMINANT CONCENTRATIONS 24
5.3 SEDIMENT 24
5.4 TREATMENT SYSTEM COMPONENT PERFORMANCE 25
5.4.1 P&T SYSTEM 25
5.4.2 ISTT 25
5.5 REGULATORY COMPLIANCE 25
5.6 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL COSTS 26
5.7 APPROXIMATE ENVIRONMENTAL FOOTPRINT ASSOCIATED WITH REMEDY 26
5.7.1 ENERGY, AIR EMISSIONS AND GREENHOUSE GASES 26
5.7.2 WATER RESOURCES 27
5.7.3 MATERIALS USAGE AND WASTE DISPOSAL 27
5.7.4 LAND AND ECOSYSTEMS 27
5.8 SAFETY RECORD 27
6.0 RECOMMENDATIONS 28
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 30
6.1.1 CONTINUE P&T OPERATION (EW-S1 TO EW-S4), WITH MONTHLY MONITORING
OF SELECT WELLS, FOR UP To ONE YEAR 30
6.1.2 ALTERNATIVE APPROACH - Do NOT OPERATE EW-S 1 TO EW-S3 DURING
INITIAL MONITORING PERIOD 31
6.2 RECOMMENDATIONS TO REDUCE COSTS 31
6.2.1 ESTIMATED COST SAVINGS FOR POTENTIAL SCENARIOS 31
6.2.2 DELAY TREATMENT PLANT UPGRADES 32
6.3 RECOMMENDATIONS FOR TECHNICAL IMPROVEMENT 32
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT 32
6.4.1 DEVELOP SHUTDOWN CRITERIA FOR EW-S 1 THROUGH EW-S4 32
6.4.2 CONSIDER ADDITIONAL REMEDIAL OPTIONS FOR THE SOURCE AREA 34
6.4.3 POTENTIAL LONG-TERM OPTIONS FOR EW-S4 35
6.5 RECOMMENDATIONS RELATED TO GREEN REMEDIATION 36
6.6 SUGGESTED APPROACH TO IMPLEMENTING RECOMMENDATIONS 36
List of Figures
Figure 6-1 Flow Chart Illustrating Suggested Decision Framework
List of Tables
Table 6-1 Cost Summary Table
Table 6-2 Summary of Effects on Environmental Footprint
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Attachments
Attachment A: Figures from Existing Site Reports
XI
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1.0 INTRODUCTION
1.1 PURPOSE
During fiscal years 2000 and 2001 independent site optimization reviews called Remediation System
Evaluations (RSEs) were conducted at 20 operating Fund-lead pump and treat (P&T) sites (i.e., those sites
with P&T systems funded and managed by Superfund and the States). Due to the opportunities for system
optimization that arose from those RSEs, the U.S. Environmental Protection Agency Office of Superfund
Remediation and Technology Innovation (OSRTI) has incorporated RSEs into a larger post-construction
complete strategy for Fund-lead remedies as documented in OSWER Directive No. 9283.1-25, Action
Plan for Ground Water Remedy Optimization. Concurrently, the EPA developed and applied the Triad
Approach to optimize site characterization and development of a conceptual site model (CSM). The EPA
has since expanded the definition of optimization to encompass investigation stage optimization using
Triad Approach best management practices (BMP), optimization during design, and RSEs. The EPA's
working definition of optimization is as follows:
"Efforts at any phase of the removal or remedial response to identify and implement specific actions that
improve the effectiveness and cost-efficiency of that phase. Such actions may also improve the remedy's
protectiveness and long-term implementation which may facilitate progress towards site completion. To
identify these opportunities, regions may use a systematic site review by a team of independent technical
experts, apply techniques or principles from Green Remediation or Triad, or apply other approaches to
identify opportunities for greater efficiency and effectiveness. " '
As stated in the definition, optimization refers to a "systematic site review," indicating that the site as a
whole is often considered in the review. Optimization can be applied to a specific aspect of the remedy
(for example, focus on long-term monitoring [LTM] optimization or focus on one particular operable unit
[OU]), but other site or remedy components are still considered to the degree that they affect the focus of
the optimization. An optimization review considers the goals of the remedy, available site data, CSM,
remedy performance, protectiveness, cost-effectiveness and closure strategy. A strong interest in
sustainability has also developed in the private sector and within Federal, State and Municipal
governments. Consistent with this interest, OSRTI has developed a Green Remediation Primer
(http://cluin.org/greenremediation/). and now routinely considers green remediation and environmental
footprint reduction during optimization reviews.
The optimization review includes reviewing site documents, potentially visiting the site for one day and
compiling this report, which includes recommendations in the following categories:
• Protectiveness
• Cost-effectiveness
• Technical improvement
• Site closure
• Environmental footprint reduction
U.S. Environmental Protection Agency (EPA). 2012. Memorandum: Transmittal of the National Strategy to Expand Superfund
Optimization Practices from Site Assessment to Site Completion. From: James. E. Woolford, Director Office of Superfund
Remediation and Technology Innovation. To: Superfund National Policy Managers (Regions 1 - 10). Office of Solid Waste and
Emergency Response (OSWER) 9200.3-75. September 28,2012.
1
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The recommendations are intended to help the site team identify opportunities for improvements in these
areas. In many cases, further analysis of a recommendation, beyond that provided in this report, may be
needed prior to implementation of the recommendation. Note that the recommendations are based on an
independent evaluation, and represent the opinions of the optimization review team. These
recommendations do not constitute requirements for future action, but rather are provided for
consideration by the Region and other site stakeholders. Also note that while the recommendations may
provide some details to consider during implementation, the recommendations are not meant to replace
other, more comprehensive, planning documents such as work plans, sampling plans, and quality
assurance project plans (QAPP).
The national optimization strategy includes a system for tracking consideration and implementation of the
optimization review recommendations and includes a provision for follow-up technical assistance from
the optimization review team as mutually agreed upon by the site management team and EPA OSRTI.
The Groveland Wells Nos. 1 and 2 Superfund Site consists of two operable units:
• Source Control (SC) operable unit (OU2), which is limited to the original release area and the
immediately surrounding property; and
• Management of Migration (MOM) operable unit (OU 1), which encompasses an approximate
850-acre area constituting the aquifer that recharges the Groveland Municipal Well Stations Nos.
1 and 2, which were impacted by site contaminants.
OU 2 is commonly referred to as the "Valley Property" or the "Valley/GRC site" because the
contaminants of concern were released from the former Valley Manufactured Products Company, located
at 64 Washington Street on property owned by Groveland Resources Corporation (GRC). The site
remedial activities are currently managed and funded by the Massachusetts Department of Environmental
Protection (MassDEP). EPA Region 1 nominated the site for an optimization review on behalf of the
MassDEP to optimize the remedy after EPA's completion of in situ thermal treatment (ISTT) in the
source area using electrical resistance heating (ERH). This optimization review focuses primarily on site
conditions following ISTT implementation.
1.2 TEAM COMPOSITION
The optimization review team consisted of the following individuals:
Name
Rob Greenwald
Peter Rich
Doug Sutton
Affiliation
Tetra Tech GEO
Tetra Tech GEO
Tetra Tech GEO
Phone
732-409-0344
410-990-4607
732-409-0344
Email
Rob . Greenwald@tetratech.com
Peter.Rich@tetratech.com
Doug. Sutton@tetratech.com
Kathy Yager, Ed Gilbert, and Gary Newhart from EPA OSRTI also attended the site visit.
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1.3 DOCUMENTS REVIEWED
The following documents were reviewed in support of the optimization review.
• Field Sampling Plan - QAPP (Nobis - February 2012)
• Monthly Site Visit Report for May 2011 (Nobis - June 13, 2011)
• Remedial Action Report for the Operable Unit 2 Remedial Action (Nobis - September 20, 2011)
• April 2011 through December 2001 Monthly Operations Reports (Nobis - June 2011 through
January 2012)
• Draft 2010 Data Evaluation Report (Nobis - May 18, 2011)
• Laboratory data reports and data management spreadsheets for 2011 groundwater monitoring data
• Second Five-Year Review Report (EPA Region 1 - June 2010)
• April 24, 2008 Letter from MassDEP to Thomas Cusick, Jr., Groveland Water Department
regarding Groveland Well No. 1.
• November 26, 2007 Memorandum from Metcalf & Eddy AECOM to Derrick Golden, EPA
Region 1 Regarding the Proposed Pumping Rate Increase at Station No. 1
• Explanation of Significant Differences, OU2 (EPA Region 1 - September 2007)
• Data Evaluation Report for Remedial Action, Spring 2003 Monitoring Round (Metcalf & Eddy,
2003)
• Supplemental Management of Migration Remedial Investigation Report (NUS Corporation -
February 1991)
• Explanation of Significant Differences, OU1 (EPA Region 1 - November 15, 1996)
• Explanation of Significant Differences, OU2 (EPA Region 1 - November 15, 1996)
• Record of Decision, OU1 (USEPA Region 1 - September 30, 1991)
• Supplemental Remedial Investigation (NUS Corporation - 1991)
• Record of Decision, OU2 (USEPA Region 1 - September 30, 1988)
• Remedial Investigation (Environmental Research & Technology, Inc. - June 1985)
1.4 QUALITY ASSURANCE
This optimization review utilizes existing environmental data to interpret the CSM, evaluate remedy
performance and make recommendations to improve the remedy. The quality of the existing data is
evaluated by the optimization review team prior to using the data for these purposes. The evaluation for
data quality includes a brief review of how the data were collected and managed (where practical, the site
QAPP is considered), the consistency of the data with other site data and the use of the data in the
optimization review. Data that are of suspect quality are either not used as part of the optimization review
or are used with the quality concerns noted. Where appropriate, this report provides recommendations to
improve data quality.
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1.5 PERSONS CONTACTED
A site visit was conducted on February 29, 2012. In addition to the optimization review team and EPA
OSRTI personnel, the following persons were present for the site visit:
Name
Janet Waldron
Derrick Golden
Paul Craffey
Kimberly White
Steve Mahoney
Diane Baxter
Frank Ricciardi
Brian Farmer
Jim Vurgaropulos
Affiliation
MassDEP
EPA Region 1
MassDEP
EPA Region 1
MassDEP
Nobis
Weston & Sampson Services
Weston & Sampson Services
Weston & Sampson Services
Email Address
Janet.waldron@state .ma.us
Golden.derrick@epa.gov
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2.0 SITE BACKGROUND
2.1 LOCATION
The Groveland Wells Nos. 1 and 2 Superfund Site is located in the Town of Groveland (Town), Essex
County, Massachusetts. The site contains nearly 850 acres, mostly located in the southwestern part of the
Town of Groveland. The Site Source Area (the Valley property) is located in the southwest portion of the
site. The site is bounded to the west by Washington Street and the former Haverhill Municipal Landfill, to
the south by Salem Street, to the east by School Street and to the north by the Merrimack River. The
Haverhill Municipal Landfill originally was part of the Groveland Wells Site but it has since been
separately listed on the National Priorities List (NPL) and is no longer part of the site. Figure 1 from the
Second Five-Year Review (EPA Region 1 - June 2010) illustrates the site boundaries and key features
(see Attachment A for this figure).
2.2 SITE HISTORY
2.2.1 HISTORIC LAND USE AND OPERATIONS
According to the Second Five-Year Review (EPA Region 1 - June 2010), the Valley property (located on
Washington Street in the southwestern portion of the site) was used for metal and plastic parts
manufacturing from 1963 until 2001. The original building, in which the Valley Manufactured Products
Company was housed, was constructed on the property around 1900. Prior to 1963 the building housed
agricultural and textile operations. In 1963, GRC leased the property and began on-site manufacturing of
screw machine products. GRC reportedly purchased the property in 1966. Valley Manufactured Products
Company acquired GRC's on-site operations in August 1979; however, GRC retained property
ownership.
A former 400 square-foot wooden shed, reportedly connected to the south end of the Valley
Manufactured Product Company building, was used to store virgin trichloroethene (TCE), "Solvosol" (an
unspecified solvent), and cutting oils. Waste cutting oils and solvents were also stored in the wooden
shed. The exact location of the shed has not been verified.
In 1972 and 1973, GRC reportedly installed six underground storage tanks (USTs) ranging in size from
700 to 3,000 gallons for storage of cutting oils, solvents and mineral spirits in the southern portion of the
Valley property. Cutting oils were pumped from the USTs into distribution piping running throughout the
machining areas of the facility. Recovered oils were recirculated through the system. Waste oils were
reportedly disposed of off-site. During October 1983, pressure testing of the USTs was conducted. The
USTs exhibited some initial pressure loss that was attributed to leakage occurring at the couplings on the
tank vent lines.
On-site processes included machining, degreasing and finishing of metal parts. The machining process
used cutting oils and lubricants. After machining, metal parts were cleaned (degreased) in a hydrocarbon
solvent vapor degreaser and then spun dry. TCE was used in the vapor degreasing operation from 1963 to
1979. Methylene chloride was used from 1979 to 1983. Solvosol and other solvents were also used. In
1984, Valley discontinued the use of solvents and replaced them with detergent degreasers.
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If parts required additional cleaning, they were then immersed in either an alkaline cleaning solution
(containing caustic soda) or an acid solution ("Brite Dip" process, containing nitric acid). Once cleaned,
the parts were rinsed and excess rinse water was discharged to a Brite Dip subsurface disposal system.
Several subsurface disposal systems were used on the property. Approximate locations of these storage
tanks and subsurface disposal systems are shown on Figure 4 of the Second Five-Year Review (EPA
Region 1 - June 2010), which is provided in Attachment A.
2.2.2
CHRONOLOGY OF ENFORCEMENT AND REMEDIAL ACTIVITIES
According to the Second Five-Year Review (EPA Region 1 - June 2010), in June and October 1979,
groundwater in two Town drinking water supply wells, Groveland Wells Nos. 1 and 2, was determined to
be impacted with TCE. The wells were taken off-line and the Town imposed water rationing. Later in
1979 the Town developed another drinking water well, Station No. 3, in a different aquifer. In 1982, the
EPA determined that the groundwater contamination at the site constituted a threat to public health and
the environment and placed the site on the NPL in December of that year. Groveland Well No. 1 was
eventually returned to service in 1987 with treatment via granular activated carbon (GAC). The
requirement for GAC treatment at the well was removed in 1994 based on non-detectable concentrations
of TCE since 1989. The following table provides a brief timeline of operational, enforcement and
remedial activities from 1982 through 2011 (derived from Table 1 of Second Five-Year Review (EPA
Region 1-June 2010)).
Date
May 1963
May 1963
1965
November 1966
1973
May 1979
August 1979
September 1979
October 1979
December 1982
1985
August 1986
1986
1987
September 1987
Late 1987 -
Early 1988
April 1988
July 1988
August 1988
September 1988
February 1991
Event
GRC leases property at 64 Washington Street in Groveland to house a metal
products manufacturing plant
GRC begins operation of metal products manufacturing
Groveland municipal well Station No. 1 is put into operation
GRC purchases property at 64 Washington Street in Groveland
Groveland municipal well Station No. 2 is put into operation
TCE detected in Station No. 1; well is shut down
Valley Manufactured Products Company acquires GRC's manufacturing operations
TCE detected in Station No. 2 Groveland municipal well Station No. 3 is put into
operation
Station No. 2 permanently shut down
Groveland Wells Site placed on the National Priorities List
Management of Migration (MOM) Remedial Investigation (RI) for the Groveland
Wells Site completed
MOM Feasibility Study (FS) for the Groveland Wells Site completed
MassDEP amendment to 1984 consent order requiring Valley/GRC to construct a
groundwater interceptor treatment unit north of Mill Pond
Installation of GAC treatment system and reactivation of Station No. 1
EPA issues consent order to Valley and GRC to conduct a Supplemental RI
Pilot study of soil vapor vacuum extraction system (SVE) at Valley site
Installation of Mill Pond Groundwater Extraction/Treatment System by
Valley/GRC
Final Phase 1 Supplemental RI Report completed by Valley/GRC subcontractor
Supplemental FS for the Valley Site completed by EPA subcontractors
Source Control (OU2) Record of Decision (ROD) for the Valley site signed
Supplemental MOM RI Report completed by EPA subcontractor
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Date
July 1991
September 1991
March 1992
May 1992
June 1992
August 1992
August 1992
October 1992
November 1992
December 1992
January 1993
May 1994
June 1994
Spring 1994
January 1995
Spring 1995
March 1996
August 1996
September 1996
April 1997
December 1997
May 1998
October 1998
April 1999
April 2000
May 2000
July/August 2000
September 2000
March 2001
Event
Supplemental MOM Feasibility Study completed by EPA subcontractor
MOM (OU1) ROD is signed
EPA issues Administrative Order to Valley/GRC to remediate soil and
groundwater at the Valley Site (i.e., the Source Control OU, OU2)
EPA issues Administrative Order to Valley/GRC to remediate groundwater
contamination that had migrated beyond the Valley Site (i.e., the part of the plume
defined as the MOM OU, OU1)
Valley/GRC informs EPA that they cannot comply with the Administrative Order
to remediate the MOM OU
EPA issues a Notice of Failure to Comply to Valley/GRC, for failure to initiate
work to remediate the MOM Operable Unit
EPA approves the SVE and groundwater treatment system design for the Valley
Site
Valley/GRC informs EPA that they cannot continue to comply with the
Administrative Order for remediation of the Source Control OU
EPA issues a Notice of Failure to Comply to Valley/GRC for failure to continue
remedial work at the Source Control OU
EPA visits Valley Site and learns that the SVE system had in fact been constructed
and was in operation
EPA issues a Second Notice of Failure to Comply to Valley/GRC for failure to
submit monthly progress reports on the SVE system
GAC treatment system at Station No. 1 is taken offline by the town, with approval
from MassDEP, because TCE contamination had not been detected in the influent
water since 1989
Valley/GRC begins routine submission of monthly progress reports to EPA
EPA subcontractor installs an extraction well and conducts hydrogeological tests at
the Valley Site for EPA
EPA approves the 100% design for the MOM OU groundwater extraction and
treatment system (GETS or P&T system)
Budget constraints cause EPA to put construction of the MOM facility on hold
EPA conducts sampling of 22 monitoring wells and determines that the plume has
decreased in extent
EPA issues Explanations of Significant Differences (ESD) for both the Source
Control and MOM OUs, modifying the remedies to treat groundwater from both
OUs in a combined facility
EPA subcontractor submits a 100% design for the combined facility
EPA approves final design
EPA receives funding for remedial action
EPA sends bid documents to qualified bidders
Remedial action subcontract awarded
Mobilization and site clearing begin
GETS (P&T system) is determined to be substantially complete. New system starts
up and Mill Pond system is shut down.
Routine operation and maintenance of the GETS (P&T system) begins
All construction punch list items are completed and final inspection is conducted
Operational and Functional Completion Report and certification are submitted to
EPA by the remedial action subcontractor
Operational and Functional Completion Report and certification are submitted to
EPA, revised to address MassDEP comments
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Date
April 2002
September 2002
April 2004
June 2005
2006
August 2006
September 2006
September 2007
January 2008
April 2009
October 2009
March 20 10
August 20 10 to
February 20 11
June 20 11
Event
SVE system is shut down and abandoned by potentially responsible parties (PRPs)
An RSE report is completed for the site
EPA initiates source area re-evaluation
First Five-Year review is completed
EPA performs chemical oxidation pilot study as part of the Source Area Re-
Evaluation
EPA removes 6 USTs and the Brite Dip system leaching field from Valley
property
EPA Source Area Re-Evaluation is completed. The report recommends using
thermal treatment technologies to treat residual contamination in the source area.
EPA issues an ESD outlining the enhancement of the existing SVE system with a
thermal treatment system. The ESD was also written to address the recalculation of
the soil clean up levels that were originally specified in the 1988 Source Area
ROD.
EPA and Valley/GRC enter into a consent decree stating Valley/GRC will pay the
government 100% of the net sale or net lease proceeds from the property
Construction of the enhanced OU2 Source Control Remedial Action begins with
site clearing and surveying
The subcontract for the OU2 SC Remedial Action ISTT system is awarded
Construction of the ISTT system begins
ISTT remediation of Source Area
Transfer of OU-1 remedy from EPA to MassDEP approximately 10 years after the
remedy was considered Operation and Functional (consistent with State -Superfund
Contract between MassDEP and EPA)
Immediately prior to the ISTT test, startup of the vapor and liquid extraction systems occurred on August
9, 2010. The ISTT system began operation on August 17, 2010. The ISTT extraction system was shut
down on February 24, 2011 and several events of confirmation monitoring of groundwater were
subsequently conducted (March 2011, August 2011, and September 2011).
2.3 POTENTIAL HUMAN AND ECOLOGICAL RECEPTORS
The review of risk assessments and toxicity factors in the Second Five-Year Review (EPA Region 1 -
June 2010) indicate that exposure to contaminated groundwater is the primary potential pathway for
human exposure to site-related contamination. Human risks associated with other potential exposure
pathways (including vapor intrusion (VI)) and ecological risks were determined to be sufficiently low to
be protective of human health and the environment either due to low levels of contamination or
incomplete exposure pathways.
2.4 EXISTING DATA AND INFORMATION
This section is based on data available from existing site documents. Interpretations included in this
section are generally those presented in the documents from which information was obtained. The
optimization review team's interpretation of this information is presented in Sections 4.0 and 5.0.
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2.4.1 SOURCES OF CONTAMINATION
According to the Second Five-Year Review (EPA Region 1 - June 2010), the primary contaminant
released at the Valley property was TCE. In 1973, 500 gallons of TCE were reportedly released to the soil
underneath the concrete slab from an UST. A total of 3,000 gallons of TCE is estimated to have been
discharged to the environment from several surface and subsurface sources, including the loading dock
drainage system, the Brite-Dip disposal system, the USTs and by routine operations practices.
The source area (OU2) addressed by ISTT in 2011, along with baseline TCE soil concentrations sampled
in 2009, are depicted on Figures 4-1 through 4-3 of the ERH Remedial Action Report (Nobis - September
20, 2011), which are provided in Attachment A. As depicted in these figures, the maximum TCE
concentrations in soil were 20,000 ng/kg, 7,400 ng/kg and 8,700 ng/kg for the 0 to 11 ft, 11 to 26 ft, and
26 to 45 ft intervals below ground surface (bgs). Concentrations of TCE in groundwater in the same area
during the 2009 baseline sampling event were as high as 96,000 ng/L, as depicted on Figure 4-4 of the
ERH Remedial Action Report (Nobis - September 20, 2011), which is provided in Attachment A. Source
area concentrations and mass were historically higher, but the concentrations noted above are
representative of the source area at the time of this review.
2.4.2 GEOLOGY SETTING AND HYDROGEOLOGY
According to the Supplemental RI (NUS Corporation - 1991), the site lies within a shallow, north-
trending bedrock valley that has been partially filled with the glacial sediments. This small valley
intersects with the Merrimack River valley along the northern edge of the site. According to the Second
Five-Year Review (EPA Region 1 - June 2010), the site is located within the Johnson Creek drainage
basin. Johnson Creek originates south of the site and flows in a northerly direction through Mill Pond,
located approximately 450 ft east of the Valley property. Argilla Brook, located to the east of Mill Pond,
flows northwest through the site and discharges to Johnson Creek. Brindle Brook is a small tributary to
Johnson Creek that flows northwestward through the southeast corner of the site area, eventually joining
with Johnson Creek near Center Street. There are limited wetland areas at the site, located mostly next to
Mill Pond, Argilla Brook, Johnson Creek, Brindle Brook and isolated areas east of Johnson Creek. A
portion of the site lies within the 100-year floodplain delineated by the Federal Emergency Management
Agency (FEMA).
Topographic relief within the valley is generally low, with most of the prominent relief due to past surface
mining of sand and gravel deposits within the valley. The overall topography in the area is controlled by
bedrock surface elevations with higher ground surface elevations south, west and east of the site being a
function of higher bedrock surface elevations in these areas.
Based on Figure 6-2 of the Draft 2010 Data Evaluation Report (Nobis Engineering - 2010), which
provides a cross-section of the geology from north to south, site geology consists of unconsolidated
overburden sediments consisting predominantly of glacial drift deposits overlying bedrock. These
deposits include both stratified and non-stratified (till) drift deposits. Along Johnson Creek and Argilla
Brook, minor amounts of alluvium are present. There is a general increase in glacial drift thickness and a
decrease in bedrock surface elevation from the valley margins to the center of the valley and from south
to north through the site. Near Groveland Municipal Well Station No. 1 there is approximately 98 ft of
glacial drift. The bedrock beneath the overburden is a phyllite (a fine-grained foliated metamorphic rock).
The Supplemental RI (NUS Corportation -1991) states that, according to Environmental Research &
Technology, Inc. (ERT 1985), the strike of this bedrock unit is to the northeast, with an average dip of 56
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degrees to the northwest. The foliation of the phyllite also reportedly dips to the north-northwest at an
angle of approximately 40 degrees.
Groundwater is encountered in both the glacial drift deposits and bedrock at the Groveland Wells Site.
The stratified glacial drift deposits form an important aquifer in the areas where a substantial thickness of
these deposits exists. Groveland Municipal wells at Stations No. 1 and 2 are located in the glacial drift
aquifer. Bedrock is moderately permeable at shallow depths, due to its highly fractured nature. At greater
depths, the frequency of fracturing and resulting permeability of the bedrock is unknown.
2.4.3 GROUNDWATER CONTAMINATION
Volatile organic compounds (VOCs) (primarily TCE) were detected in groundwater on the Valley
property. Prior to remediation, concentrations as high as 150,000 (ig/L of TCE and 7,900 (ig/L of 1,2-
DCE were reported in groundwater samples collected from wells bordering the Valley property. Similarly
high concentrations of TCE and other chlorinated VOCs were detected in groundwater under the portion
of the Valley property known as the Material Storage Area, which was constructed in 1980. Both spent
and unused cutting oils and solvents had been stored in drums and USTs in this area. Inorganic analytes
were also detected in groundwater under the Material Storage Area slab, including: arsenic at 230 (ig/L,
chromium at 70 (ig/L, copper at 1,100 (ig/L and lead at 130 (ig/L. A free oil phase was also observed in
some groundwater samples.
The RIs revealed that a large groundwater contaminant plume of primarily TCE and 1,2-DCE extended
from the Valley property approximately 3,900 ft northward, along the path of Johnson Creek,
downgradient past Station No. 2. The plume width in 1991 was approximately 350 ft in the Valley/Mill
Pond area and roughly 1,000 ft wide where it encompassed Station No. 2. The contamination resulted in
the need to provide GAC treatment for water from Groveland Well Station No. 1, while Station No. 2 was
completely shut down. Concentrations as high as 50,000 (ig/L TCE were reported near the Valley
property, while concentrations near the Town wells were generally less than 100 (ig/L, but above the
MCL of 5 (ig/L. Several inorganics were also detected in site groundwater at concentrations exceeding
MCLs, but it was also noted that concentrations of some inorganics in samples from wells upgradient of
the site also exceeded MCLs.
Remedial activities have greatly reduced the concentrations and extent of contaminants in groundwater.
The recent Field Sampling Plan - QAPP (Nobis, 2012) states that "based on the long term groundwater
monitoring and recent ISTT confirmation sampling conducted at the site, the contaminants of concern are
generally limited to TCE and cis-l,2-DCE in site soil and groundwater located within the source area
(Valley Manufacturing property) and in groundwater within the downgradient plume." Recent TCE
concentrations in the overburden (Fall 2010) are illustrated on Figure 4 from the Field Sampling Plan -
QAPP (Nobis, 2012). The greatly diminished extent of the overall VOC plume is depicted on Figure 2-1
of the ERH Remedial Action Report (Nobis - September 20, 2011), which is provided in Attachment A.
Figure 7 from the Second Five-Year Review (EPA Region 1 - 2010), which is provided in Attachment A,
depicts the concentrations of TCE in bedrock wells in 2009, prior to the ISTT remedy.
A detailed discussion regarding the substantial concentration reductions provided by the recent ISTT
remediation in the source area is presented in Section 4.1.
2.4.4 SOIL CONTAMINATION
Contaminated soil requiring remediation was limited to the soils addressed by the Source Control OU.
Surface soil at the Valley property was not found to be contaminated, but subsurface soil was found to be
10
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contaminated with VOCs, primarily TCE and methylene chloride, with lower concentrations of other
chlorinated VOCs such as 1,1,1-trichloroethane, tetrachloroethene (PCE), and 1,2-trans-dichloroethene.
TCE is the primary contaminant of concern (COC) in soil at the Valley property.
The highest levels of subsurface soil contamination were found in the southernmost portion of the Valley
property within 10 ft of the solvent storage tank. Analysis of subsurface soil gas samples collected from
an area under the Valley building prior to remediation detected total VOC concentrations as high as 1,300
parts per million (ppm), indicating that additional subsurface soil contamination was likely to be present
under the portion of the building that was constructed in 1974.
As stated earlier, the baseline TCE soil concentrations sampled in 2009, prior to the ISTT remediation,
are depicted on Figures 4-1 through 4-3 of the ERH Remedial Action Report (Nobis - September 20,
2011), which is provided in Attachment A. As depicted on these figures, the maximum TCE
concentrations in soil were 20,000 ng/kg, 7,400 ng/kg and 8,700 ng/kg for the 0 to 11 ft, 11 to 26 ft, and
26 to 45 ft intervals below ground surface (bgs).
The recent ISTT remediation has eliminated the majority of soil contamination. A detailed discussion
regarding the substantial concentration reductions provided by the recent ISTT remediation in the source
area is presented in Section 4.1.
2.4.5 SEDIMENT AND SURFACE WATER CONTAMINATION
The Second Five-Year Review (EPA Region 1 - June 2010) states that the RIs determined that sediment
and surface water contamination were low level and sporadic. Detections of VOCs in surface water were
below Ambient Water Quality Criteria (AWQC) and the EPA determined that the low level of sporadic
contamination in sediment presented minimal risk to human health and the environment.
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3.0 DESCRIPTION OF PLANNED OR EXISTING REMEDIES
This section is based on information available from existing site documents. Interpretations included in
this section are generally those presented in the documents from which the information was obtained. The
optimization review team's interpretation of this information and evaluation of remedy components are
presented in Sections 4.0 and 5.0.
3.1 REMEDY AND REMEDY COMPONENTS
This section describes the following remedy components:
• Former SVE system
• P&T system
• ISTT remediation in the source area
3.1.1 FORMER SVE SYSTEM
An SVE system in the source area was constructed and began operations in 1992. The SVE system was
operated and maintained by Valley's contractor from approximately December 1992 through April 2002.
Historical data for the SVE system indicated that only a nominal amount of TCE was removed and the
system was minimally effective in reaching soil clean up goals throughout the site. Additionally, there
was a pilot test of in situ chemical oxidation (ISCO) using potassium permanganate as part of a 2006
Source Area Re-evaluation, but ISCO was minimally effective due to the heterogeneity of the subsurface
soils and the potential presence of NAPL. The previous SVE system and ISCO pilot tests are not a focus
of this optimization evaluation, and are not discussed further.
3.1.2 P&T SYSTEM
The P&T system has consisted of a network of up to 10 extraction wells located as shown on Figure 2 of
the Field Sampling Plan - QAPP (Nobis - February 2012), which is provided in Attachment A. Only 4
of the 10 extraction wells were operating at the time of the site visit:
• The three source area extraction wells (EW-S1 through EW-S3) were shut down for the ISTT
remediation in the source area, and are planned to be re-started when groundwater temperature
declines below 100 degrees F.
• Three of the extractions wells (EW-M2, G-l, and G-2) have been shut down due to low VOC
concentrations.
The table below summarizes the design rate and typical extraction rates for each well.
12
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Well
Design Extraction Rate
(gallons per minute)
Typical Observed Extraction Rates
(gallons per minute)
Source Area Wells
EW-S1
EW-S2
EW-S3
2
2
2
3*
0.4*
0.5*
South of Mill Pond
EW-S4
EW-S5
5
2
40
1
North of Mill Pond
EW-M1
EW-M2
EW-M3
G-l
G-2
35
35
2
20
20
30
Off since August 2008
0.6
Off since 2002
Off since 2002
*Not operating at the time of the site visit. These wells had been turned off during the ISTT remediation of the
source area and are scheduled to be re-activated once temperatures in groundwater decline to less than 100 degrees
F.
Double-walled underground pipelines with leak detection transport the extracted groundwater from the
extraction wells to the Groundwater Treatment Facility (GWTF) for treatment. The GWTF is located
behind the Valley building on property owned by the Archdiocese of Boston. All unit operations are
contained in the same building, including:
• Pretreatment consisting of equalization, clarification and filtration to remove suspended solids
(grit and precipitated metals, primarily iron). Hydrogen peroxide (2 ppm) is added into the 8,000
gallon equalization tank. There are two 3 horsepower (HP) pumps to move water from the
equalization tank (one used at a time) to the incline plate clarifier. These pumps have variable
frequency drives (VFDs) set to approximately 35% (33 Hz). Sludge is generated via an incline
plane clarifier (no polymer addition needed), and moved to a thickener approximately once per
week using one of two parallel double diaphragm sludge pumps. Sludge is disposed of off-site
approximately once per 5 years as non-hazardous solid waste. Two 15 HP pumps (one used at a
time) then move water through the sand filters, which consist of three US Filter multimedia filters
arranged in parallel (each filter has a capacity of 75 gpm). These pumps have VFDs and operate
at approximately 34 Hz. The sand filters are backwashed approximately once every 2 weeks with
a cycle lasting approximately 20 minutes, so the backwash pump (one of two 20 HP pumps
operating at approximately 43 Hz) is used very infrequently.
• After sand filtration, the water is treated to destroy VOCs via ultraviolet oxidation (UVOx) with
hydrogen peroxide (6 ppm) as oxidant. The water passes from the sand filter to the UVOx system
with no additional pump required. Only one of the four UVOx lamps (30 kW) operates at a time
(lasts approximately 3,000 hours).
• Catalytic activated carbon adsorption is used for destruction of residual hydrogen peroxide, to
prevent effluent toxicity. The catalytic carbon unit contains 3,000 pounds of carbon and is rated
for approximately 150 gpm.
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• Process water from the catalytic carbon unit flows to a 5,600 gallon effluent tank, followed by
discharged via gravity through an underground pipeline that emerges at an outfall constructed on
the western shore of Mill Pond.
• Vapor phase carbon adsorption is used for treating off-gases from various tanks. Two 1,000
pound vapor phase GAC units are aligned in series to treat VOC-laden air from the head space of
the influent, filter feed and decant tanks as well as the clarifier.
Total hydrogen peroxide use (for influent and UVOx) is approximately 2 gallons per day of a 20 percent
solution.
3.1.3 ISTT REMEDIATION IN THE SOURCE AREA
The goal of the ISTT was to reduce the contaminant concentrations in source area soils and overburden
groundwater to below their respective cleanup goals. An alternative performance endpoint was to
terminate before attainment of the cleanup goals if the contaminant removal rate diminished to the point
where continued operation of the ISTT system was not cost effective, i.e., the point of diminishing
returns. Performance objectives were to achieve (1) a minimum temperature in the vadose zone (0-25 ft)
of 90 degrees C and (2) a minimum temperature in the saturated zone (25-45 ft) of approximately 100
degrees C. Performance metrics included (1) 85percent of the temperature sensors in the vadose zone
reach 90 degrees C, (2) 85 percent of the temperature sensors in the saturated zone reach about 100
degrees C, and (3) 100 percent of all temperature sensors reach 60 degrees C.
Nobis contracted TerraTherm, Inc. to design, construct, and operate the ISTT system, which consisted of
four areas with treatment depths ranging from 10 to 45 ft. The total treatment zone was approximately
14,830 square ft with a volume of 17,450 cubic yards (see Figure 3-1 of the ERH Remedial Action
Report, which is provided in Attachment A. The ISTT system included 40 standard electrode wells, 24
mini-electrode wells, 29 shallow SVE wells, 15 multi-phase extraction wells, 16 temperature sensor wells
and 12 temperature, pressure and vacuum sensor wells. In total, 143 electrodes were installed.
Construction of the ISTT Source Control remedy began in April 2009, with site clearing and a
geophysical survey of the treatment area. In July and August of 2009, site preparation continued with the
abandonment of all polyvinyl chloride (PVC) monitoring wells and replacement of a subset of the original
wells with stainless steel monitoring wells that would be used for baseline and confirmation monitoring of
groundwater. Baseline sampling of Source Area soil and groundwater was also performed in summer
2009 to assist in ISTT design and establish baseline conditions. In March 2010, construction of the ISTT
system was initiated. Startup of the vapor and liquid extraction systems was on August 9, 2010 and the
ISTT system was commissioned on August 17, 2010. The ISTT extraction system was shut down on
February 24, 2011. From August 9, 2010 to February 24, 2011 (192 days of operation), the total volume
of liquid removed by ISTT was 2,244,363 gallons. The total amount of energy used during ISTT
operations was approximately 3,639,520 kilowatt hours (kWh).
3.2 RAOs AND STANDARDS
This section provides a summary of remedial action objectives (RAOs) for groundwater, cleanup
standards for groundwater and soil and treatment standards for the GWTF.
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3.2.1 REMEDIAL ACTION OBJECTIVES FOR GROUND WATER
The Second Five-Year Review (EPA Region 1 - 2010) summarizes the RAOs for Source Control OU2 as
follows:
• Prevent ingestion of groundwater contaminated in excess of relevant and appropriate drinking
water standards or, in their absence, an excess cancer risk level of 10"6, for each carcinogenic
compound. Also, to prevent ingestion of groundwater contaminated in excess of a total excess
cancer risk level for all carcinogenic compounds of 10"4 to 10"7;
• Prevent ingestion of groundwater contaminated in excess of relevant and appropriate drinking
water standards for each non-carcinogenic compound and a total hazard index greater than unity
for all non-carcinogenic compounds;
• Prevent migration of contaminants in soils and groundwater that would result in groundwater
contamination in excess of relevant and appropriate drinking water standards and surface water
contamination in excess of relevant and appropriate AWQC for the protection of aquatic life; and
• Remediate inorganic contamination to the extent that such remediation is incidental to organics
remediation and to evaluate attainment of the applicable or relevant and appropriate requirements
(ARARs) of federal and state environmental regulations.
The Second Five-Year Review (EPA Region 1 - 2010) summarizes the RAOs for MOM OU1 as follows:
• To prevent ingestion of groundwater contamination in excess of relevant and appropriate drinking
water standards or, in their absence, an excess cancer risk level of 10"6 for each carcinogenic
compound. Also, to prevent ingestion of groundwater contaminated in excess of a total excess
cancer risk level for all carcinogenic compounds of 10"4 to 10"6.
• To prevent ingestion of groundwater contaminated in excess of relevant and appropriate drinking
water standards for each non-carcinogenic compound and a total hazard index greater than unity
for non-carcinogenic compounds having the same target endpoint of toxicity.
• To restore the groundwater aquifer to relevant and appropriate drinking water standards or, in
their absence, the more stringent of an excess cancer risk of 10"6 for each carcinogenic compound
or a hazard quotient of unity for each non-carcinogenic compound. Also, restore the aquifer to the
more stringent of (1) a total cumulative excess cancer risk of 10"4 to 10"6 and/or (2) a total
cumulative hazard index not to exceed an acceptable range for noncarcinogenic compounds
having the same target endpoint of toxicity.
3.2.2 CLEANUP STANDARDS FOR GROUNDWATER AND SOIL
The current standards for groundwater contaminants of potential concern that were listed in the MOM OU
ROD are listed in the table below, which is based on Attachment 3 -Table 1 of the Second Five-Year
Review (EPA Region 1-2010).
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Contaminants of
Potential Concern Listed
in the MOM OU ROD
Federal Safe Drinking
Water Act
(SDWA)Standards
MCL
(mg/L)
MCLG
(mg/L)
Massachusetts
Drinking
Water
Standards
(mg/L)
Massachusetts
Drinking
Water
Guidelines
(mg/L)
RCRA
MCL
(mg/L)
Organic Compounds
Acetone
Benzene
Chlorobenzene
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis-l,2-Dichloroethene
trans- 1,2-Dichloroethene
Methylene chloride
Tetrachloroethene
Toluene
1,1,1 -Trichloroethane
Trichloroethene
Vinyl chloride
—
0.005
0.1
~
0.005
0.007
0.07
0.1
0.005
0.005
1
0.2
0.005
0.002
—
0
0.1
~
0
0.007
0.07
0.1
0
0
1
0.2
0
0
—
0.005
0.1
~
0.005
0.007
0.07
0.1
0.005
0.005
1
0.2
0.005
0.002
6.3
—
—
0.07
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Inorganic Compounds
Arsenic
Barium
Berylium
Cadmium
Chromium (total)
Mercury (inorganic)
Selenium
Silver
Vanadium
0.01
2
0.004
0.005
0.1
0.002
0.05
0.1
—
0
2
0.004
0.005
0.1
0.002
0.05
0.1
—
0.01
2
0.004
0.005
0.1
0.002
0.05
0.1
—
—
—
—
—
—
—
—
—
—
0.05
0.01
0.05
0.002
Other Analytes Detected in Groundwater
Antimony
Lead
Nickel
0.006
'P'p*
~
0.006
0
~
0.006
'P'p*
~
—
~
0.1
—
0.05
~
* TT: Treatment technique. Lead and copper are regulated by a treatment technique that requires systems to control
the corrosiveness of their water. If more than 10 percent of tap water samples exceed the action level, water
systems must take additional steps. The action level for copper is 1.3 milligrams per liter (mg/L) and for lead is
0.015 mg/L.
MCLG = maximum contaminant level goal
RCRA = Resource Conservation and Recovery Act
16
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A summary of groundwater cleanup levels for VOCs is provided in Table 2 of the recent Field Sampling
Plan - QAPP (Nobis - 2012) as follows:
Compound
Trichloroethene
1 , 1 -Dichloroethene
Trans- 1 ,2 -Dichloroethene
Cis- 1 ,2-Dichloroethene
Methylene Chloride
Tetrachloroethene
1,1,1 -Trichloroethane
Toluene
Vinyl Chloride
Groundwater Cleanup Level
(HS/L)
5
7
100
70
5
5
200
1,000
2
As summarized in Table 2 of the recent Field Sampling Plan - QAPP (Nobis, 2012); /Jg/L - micrograms/liter.
The Second Five-Year Review (EPA Region 1 - 2010) provides the following discussion regarding
cleanup standards for subsurface soil in the source area:
"Soil cleanup levels were developed in the Source Control ROD to be protective of the potential
leaching of organic compounds to groundwater based on 1988 default soil/water equilibrium
partitioning assumptions. The 2005 Five-Year Review determined that the ROD soil cleanup levels
were overly protective of both direct contact and leaching to groundwater using a comparison to
Region 9 residential PRGs (EPA, 2004b) and to generic Soil Screening Levels (EPA, 2002b)
protective of contaminant migration to groundwater (using the EPA recommended dilution
attenuation factor of 20). Therefore, a re-evaluation of the soil cleanup levels was recommended.
The 2007 BSD established new soil clean-up goals based on recalculation using site-specific soil
characteristics. The new levels were also developed based on the following guidance: Soil Screening
Guidance: User's Guide, April 1996, OSWER Directive 9355.4-23 and the Supplemental Guidance
for Developing Soil Screening Levels for Superfund sites, August 2001, OSWER Directive 9355.4-
24. These recalculated site-specific soil cleanup levels are protective of groundwater (MCLs), direct
contact exposures (i.e., the incidental ingestion, dermal contact and inhalation of dust released from
the soil), and for the subsurface vapor intrusion pathway (i.e., the inhalation of contaminated air)."
The table below summarizes the cleanup standards for soil as per the 2007 BSD.
Compound
Trichloroethene
Vinyl Chloride
Methylene Chloride
Tetrachloroethene
1 , 1 -Dichloroethene
Trans- 1 ,2-Dichloroethene
Toluene
1,1,1 -Trichloroethane
Cis- 1 ,2 -Dichloroethene
2007 ESD Cleanup Level for Soil
(Hg/kg)
77
11
22
56
45
626
22,753
1,388
418
Summarized from Second Five-Year Review, which references the 2007 Explanation of Significant Differences
(ESD); ug/kg = microgram/kilogram.
17
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3.2.3
STANDARDS FOR TREATMENT PLANT
Effluent from the GWTF discharged to Mill Pond is expected to meet "Average Monthly Surface
Water/Mill Pond Discharge Limits (|ig/L)". The effluent discharge limits in the following table were
included in spreadsheets provided to the optimization review team. The specific source of these limits is
not identified, but it is the understanding of the optimization review team that these limits were calculated
by the EPA based on assumptions of turnover in Mill Pond.
Parameter
Volatile Organic Compounds
Vinyl Chloride
1 , 1 -Dichloroethene
Acetone
2-Butanone
Methylene Chloride
1,2-Dichloroethene (total)
1 , 1 -Dichloroethene
1,1,1 -Trichloroethane
Benzene
Trichloroethene
Toluene
Carbon Tetrachloride
1,1, 2 -Trichloroethane
Tetrachloroethene
Chlorobenzene
Metals
Silver
Arsenic
Barium
Beryllium
Cadmium
Chromium (total)
Iron
Mercury
Manganese
Nickel
Lead
Antimony
Selenium
Vanadium
Zinc
Daily
Maximum Discharge Limit
(Hg/L)
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
0.9
Not Listed
Not Listed
Not Listed
2.3
41
Not Listed
Not Listed
Not Listed
355
34
Not Listed
Not Listed
Not Listed
Not Listed
Average
Monthly Discharge
Limit
(Hg/L)
2,816
17.2
Not Listed
Not Listed
8,600
172
Not Listed
500
381
434
2,500
Not Listed
Not Listed
47.7
112,600
Not Listed
0.75
5,400
10
2.0
27
Not Listed
0.273
Not Listed
39
1.3
23,000
12
Not Listed
Not Listed
ug/kg = microgram/kilogram; ug/L = microgram/liter.
18
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Of particular note is the low average monthly discharge limit for arsenic of 0.75 (ig/L. Arsenic is not
currently considered a COC at the site; rather it is a natural constituent of site soil and ground water.
However, because it is present in GWTF influent above the discharge limit of 0.75 (ig/L (influent
concentration for arsenic is typically on the order of < 5 (ig/L to > 20 (ig/L depending on which extraction
wells are operating) the water must be treated for arsenic prior to discharging it to Mill Pond. It is likely
that no treatment for arsenic would be otherwise be required (i.e., if TCE remediation was considered
complete or if treated water was recharged to groundwater).
The optimization review team did not notice specific discharge standards for vapors from the vapor GAC
units referenced in site documents. The site team indicated after the site visit that the discharge "standard"
is the MassDEP Policy "Off-Gas Treatment of Point-Source Remedial Air Emissions", and that the
discharge from the vapor GAC units was modeled and met the 95 percent reduction requirement.
3.3 PERFORMANCE MONITORING PROGRAMS
This section discussed routine sampling conducted as part of the remedy. Non-routine sampling, such as
the soil sampling associated with the ISTT remedy in the source area, is not discussed in this section.
Groundwater Monitoring Wells
The Field Sampling Plan - QAPP (Nobis - February 2012) indicates that long-term groundwater
monitoring events have been routinely conducted in the spring and fall on a semi-annual basis since 1998.
Typically, the sampling events have consisted of a smaller spring event (high water table) and a
comprehensive fall event (lower water table). The document states that VOC concentrations have
historically been higher during the fall, such that comprehensive monitoring events are most appropriately
conducted in the fall.
According to Table 3 of the Field Sampling Plan - QAPP (Nobis - February 2012), future groundwater
monitoring is anticipated to include the following number of wells:
• Fall events
o 13 wells in the downgradient plume area (two shallow overburden, six overburden, five
bedrock)
o 16 wells in the source area (11 overburden, five bedrock)
• Spring Events
o 10 wells in the downgradient plume area (two shallow overburden, four overburden, four
bedrock)
o 12 wells in the source area (eight overburden, four bedrock)
There are also quality assurance/quality control (QA/QC) samples (blanks/duplicates). Water level events
are conducted semiannually, and include wells across the site as well as from monitoring points at the
north and south ends of Mill Pond.
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Many of the source area wells that were historically sampled for groundwater LTM were removed prior to
the OU2 ISTT remedial action because they were constructed of PVC and would have been damaged
during ISTT operations. Those historical source area wells have been replaced with 13 new stainless steel
monitoring wells that will be sampled in the future. This recent sampling plan has eliminated the
following monitoring wells in the downgradient plume area from the monitoring program due to a long
period of non-detect or very low concentrations of TCE and cis-l,2-DCE during historical sampling
events:
• Overburden wells ERT-11, ERT-13, ERT-16 and ME-1OD
• Bedrock wells DEQE-13D, 109 and NUS-4A
Wells are generally sampled with passive diffusion bag (PDB) technology. The PDBs are allowed to
equilibrate with the aquifer for approximately 21 days prior to retrieval for analysis. Three of the new
source area wells will initially be sampled with low-flow techniques until the temperature declines from
the ISTT remediation (but are expected to be sampled with PDBs in the future). Analysis is for VOCs
using EPA Method 8260B. The first time PDBs are used to sample a monitoring well, several PDBs are
deployed spanning the well screen. Four samplers are used in wells with 10 ft screens; eight samplers
where screens are 20 ft. Data from the initial event are evaluated to determine the sampling depth for
future sampling events.
Groundwater Extraction Wells
Nine of the extraction wells are sampled quarterly, as part of the GWTF operations and maintenance
(O&M) activities (well G-l was eliminated from the sampling program in 2002), with analysis for VOCs
and metals.
GWTF
The influent and effluent from the GWTF are monitored on a monthly basis for VOCs and metals to
confirm that effluent discharge limits are not exceeded and to observe contaminant removal efficiencies.
An in-line VOC analyzer for groundwater effluent was removed in early 2011 (such units are typically
difficult to maintain and provide limited benefit).
Since the effluent from the GWTF is discharged to surface water, it is tested for acute and chronic toxicity
on a quarterly basis. Toxicity testing includes 48-hour whole effluent screening tests with Ceriodaphnia
dubia and juvenile fathead minnow (Pimephales promelas). The survival of both test species is measured
during the test, as well as the growth of the fathead minnow and the reproduction of Ceriodaphnia.
VOC concentrations at three points along the vapor GAC units (influent, between the two units, and
effluent) are measured quarterly. The optimization review team assumes these measurements are
conducted with a photoionization detector (PID).
Surface Water
No surface water sampling is currently conducted. Surface water samples were previously collected from
Mill Pond in the spring of 2000, prior to GWTF startup, and again during the spring of 2001, 2002, and
2003. Samples were analyzed for VOCs and metals. The purpose of the sampling was to monitor the
impact of the GWTF discharge on Mill Pond. Results showed no significant difference in the level of
contaminants or change in water quality in Mill Pond following startup of the GWTF or after 3 years of
operation. Surface water sampling was discontinued in 2004 because the treatment plant discharge had no
adverse effects during the first 3 years of operation.
20
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4.0 CONCEPTUAL SITE MODEL
This section discusses the optimization review team's interpretation of existing characterization and
remedy operation data and site visit observations to explain how historic events and site characteristics
have led to current conditions. This CSM may differ from that described in other site documents. CSM
elements discussed are based on data obtained from EPA Region 1 and discussed in the preceding
sections of this report. This section is intended to include interpretation of the CSM only. It is not
intended to provide findings related to remedy performance or recommendations for improvement.
Review findings and recommendations are provided in Sections 5.0 and 6.0, respectively.
4.1 CSM OVERVIEW
The Valley property is located on the shoulder of a local topographic and bedrock high that is overlain by
approximately 40 ft of unconsolidated overburden sediments, approximately 30 ft of which is unsaturated
and 10 ft of which is saturated. TCE releases at the Valley property caused soil and groundwater
concentrations indicative of the presence of NAPL in unsaturated zone and the thin saturated overburden
on the southeastern portion of the Valley property. Due to the relatively thin saturated zone of
contamination in the source area and mixing with regional groundwater flow, concentrations of TCE in
groundwater approximately 500 ft downgradient of the source area were approximately a half order of
magnitude lower (6,600 ng/L at EW-S5 compared to 40,000 ng/L at EW-S2) prior to any P&T operation.
During approximately 10 years of P&T operation, the TCE concentrations in the source area P&T wells
(EW-S1 through EW-S3) remained high, suggesting a continuing source of groundwater contamination.
By contrast, TCE concentrations at the next set of downgradient wells (EW-S4 and EW-S5) decreased by
a factor of approximately 30 within 2 years, indicating a significant degree of capture provided by the
source area P&T wells. Due to a relatively steep hydraulic gradient (approximately 0.06 ft per ft) between
the source area and EW-S4/EW-S5, and a high hydraulic conductivity (a value of approximately 50 ft per
day is representative based on values provided in RI reports), the groundwater flow velocity is relatively
fast, and TCE concentrations in this area change relatively quickly as a result of remedial activities.
Despite historic TCE concentrations initially as high as 6,600 ng/L in EW-S5 prior to pumping, TCE
concentrations decreased below the MCL permanently after approximately 8 years of operation. TCE
concentrations in EW-S4 also decreased substantially, but never declined below the MCL, indicating the
source area wells provided a high degree of source control but not full source control. Monitoring data for
the wells downgradient of EW-S4 and EW-S5 suggest that EW-S4 and EW-S5 (and the upgradient source
area extraction wells) have provided sufficient plume capture to allow downgradient areas to achieve the
MCL for TCE. Extraction wells downgradient of EW-S4 and EW-S5 have contributed to capturing the
portion of the plume that had migrated past EW-S4 and EW-S5 prior to P&T system operation.
The recent ISTT remedy in the source area removed the majority of mass and has reduced TCE
concentrations in soil and groundwater near the source area accordingly. However, the confirmation soil
sample analyses from CSB-10 (5,600 ng/kg of TCE between 23 and 25 ft bgs) and CSB-13 (7,000 ng/kg
of TCE between 3 to 5 ft bgs) are nearly 2 orders of magnitude higher than the site-specific soil cleanup
standard of 77 ug/kg for TCE, and suggest that contamination is still present in vadose zone soil and has
the potential to result in TCE groundwater contamination orders of magnitude above MCLs. The August
21
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2011 TCE concentration of 78 (ig/L in groundwater from well RW-05 (the latest round of sampling at that
location available to the optimization review team), which is located very close to well CSB-10, further
suggests the potential that a source of groundwater contamination remains in this area. It is unclear,
however, if these observed soil and groundwater concentrations are isolated and of insufficient mass to
serve as the source for an extensive TCE plume above MCLs, or if they merit further attention. Resuming
operation of EW-S1, EW-S2, and EW-S3 and sampling them while they operate should provide a
representative concentration of TCE in the source area. Based on the TCE concentration at well TW-31
(located just downgradient of the three source area P&T extraction well locations) sampled following the
ISTT remedy, it appears that a limited amount of TCE may have escaped the ISTT zone during
remediation. A minor temporary increase in the TCE concentration at EW-S4 (further downgradient from
TW-31) might be expected over the next several months. Plume maps from the ERH Remedial Action
Report (Nobis - September 20, 2011) depicting soil and groundwater TCE contamination from the
baseline (2009) event and three events subsequent to the ISTT remedy are provided in Attachment A.
Concentrations of cis-l,2-DCE in groundwater are generally more than two orders of magnitude lower
than the TCE concentrations, suggesting limited or no TCE degradation. Sampling for 1,4-dioxane was
conducted at the site in 2003; 1,4-dioxane was not detected at a detection limit of 1.0 ng/L.
Site hydrogeology and water quality data suggest to the optimization review team that very little of the
water extracted by the Town well comes from the site, and that the majority of the water extracted by the
well in the stratified drift dilutes the contaminated water such that the blended concentration of TCE is
not detectable. For example,TCE concentrations as high as 45,000 ug/L were detected in 1984 at the north
end of Mill Pond and concentrations in the Town wells were as high as 118 ug/L, suggesting an
approximate dilution factor of almost 400. As concentrations at the north end of Mill Pond decreased due
to remedy operation, TCE concentrations at the Town well decreased below detection limits and TCE
concentrations in most monitoring wells decreased to below the MCL. In the nine sampling events from
September 2007 through Fall 2011, the maximum detected TCE concentration north of Mill Pond has
been below 10 ug/L; and below the MCL in four of the nine sampling events. Additionally, TCE
concentrations at EW-S4 (south of Mill Pond) are also in the range of 10 ug/L or less except for a
potential upcoming pulse of dissolved contamination associated with migration when EW-S1 through
EW-S3 were not operating during the ISTT remedy. Using an approximate TCE concentration of 10 ug/L
in the vicinity of Mill Pond, the approximate dilution factor of 400 and a reasonable factor of safety, the
optimization review team would expect TCE to remain below detection limits in groundwater samples
collected from the Town well.
Based on these observations, the optimization review team suggests that the focus of site remediation be
on the remaining TCE contamination in the source area and between the source area and EW-S4.
4.2 CSM DETAILS AND EXPLANATION
This section provides and additional details and further explanation of key CSM-related review
observations.
4.2.1 POTENTIAL IMPACT OF SOIL CONTAMINATION ON GROUNDWATER
The partitioning coefficient (Kd) governs the equilibrium concentration between soil and groundwater that
are in direct contact, as follows:
Concentration in Soil (mg/kg) = Kd (L/kg) x Concentration in Groundwater (mg/L)
22
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The partitioning coefficient is the product of the organic carbon partitioning coefficient (Koc) and the
fraction of organic carbon in the soil (foc) (i.e, Kd = Koc xfoc). According to the EPA Soil Screening
Guidance (http://www.epa.gov/superfund/health/conmedia/soil/). the Koc for TCE is approximately 100
liters per milligram (L/mg). The/^c is not known, but might be between 0.001 and 0.003. Kd is therefore
approximately 1 liter per kilogram (L/kg) to 3 L/kg. Therefore, for remaining TCE soil concentration of
7,000 ng/kg (7 mg/kg) at CSB-13, TCE concentrations for groundwater in direct contact with that soil
could be as high as 23 mg/L to 70 mg/L. This is not the concentration that would be expected in
groundwater underlying the contaminated unsaturated soil because some degree of attenuation or dilution
would be expected. However, it becomes evident that groundwater that comes in contact with this soil or
infiltrating water that passes through this soil could result in TCE groundwater concentrations well above
the MCL.
4.2.2 DATA GAPS
The primary data gaps are the extent, magnitude and distribution of contamination remaining in the
source area and the potential for that TCE to migrate downgradient and ultimately impact groundwater at
concentrations above the MCL, including groundwater in bedrock in, and immediately downgradient of,
the source area. Wells RW-07B and RW-10B were installed in bedrock in the source area but not in the
vicinity of the highest source area concentrations. Remedy extraction wells EW-S1 through EW-S3
extract from both the overburden and bedrock, and EW-S4 extracts groundwater from the bedrock
approximately 500 ft downgradient of the source area. Because the ISTT remedy significantly reduced the
level of contamination in the overburden (but did not directly address bedrock), continued sampling of the
bedrock wells will indicate if high levels of contamination are present in groundwater in the source area
bedrock. Sampling to date of the source area monitoring and extraction wells subsequent to the ISTT
remedy suggests that TCE is present in bedrock groundwater at concentrations above MCLs between the
source area and EW-S4, but not at concentrations that would merit further investigation or targeted
remediation of bedrock. Sampling during continued extraction well operation will provide more
information about the nature of contamination in this area.
4.3 IMPLICATIONS FOR REMEDIAL STRATEGY
Despite the success of the ISTT remediation with respect to TCE concentration reductions in both soil and
groundwater in the source area, soil analytical results from confirmation soil borings (CSB-10 and CSB-
13) indicate that some residual contamination remains in the unsaturated overburden. Given this finding,
additional source area remediation efforts (if any) would need to target portions of the unsaturated zone
and possibly portions of the saturated zone. Continued source area P&T efforts would not speed progress
to restoring groundwater in the source area below MCLs. It would, however, help control groundwater
impacts that would otherwise migrate from the source area.
Data from continued groundwater monitoring in and downgradient of the source area may or may not
suggest that the remaining source area contamination merits additional remediation or continued
extraction. Clear criteria should be developed for discontinuing operation of individual extraction wells to
prevent operation of a system after it is no longer providing a meaningful benefit for plume control or
aquifer restoration.
23
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5.0 FINDINGS
This section presents the observations and interpretations of the optimization review team. These are not
intended to imply a deficiency in the work of the system designers, system operators or site managers, but
rather are offered as constructive suggestions in the best interest of the EPA and the public. These
observations have the benefit of being formulated based upon operational data unavailable to the original
designers. Furthermore, it is likely that site conditions and general knowledge of groundwater remediation
have changed over time.
5.1 SOURCES
Please refer to Section 4.1 for a discussion regarding the remaining source of contamination and
associated data gaps.
5.2 GROUNDWATER
5.2.1 PLUME DELINEATION
The area of the TCE plume with concentrations currently exceeding the MCL is primarily located at and
upgradient of EW-S4, including the source area. Other areas historically impacted by the TCE plume now
have TCE concentrations below the MCL. Plume maps illustrating recent TCE concentrations in
groundwater, in both the overburden and the bedrock, are discussed in Section 2.4.3. Although TCE was
present above over 100 ng/L downgradient of Mill Pond as recently as 2001, TCE has not been detected
in the Town wells since 1989, indicating that the TCE present in groundwater extracted by the Town
wells is significantly diluted by the high rate of groundwater extraction from the stratified drift.
5.2.2 PLUME CAPTURE
Please refer to Section 4.0 for a discussion regarding plume capture.
5.2.3 GROUNDWATER CONTAMINANT CONCENTRATIONS
Please refer to Sections 2.4.3 and 4.1 for a discussion regarding groundwater contamination
concentrations.
5.3 SEDIMENT
Sediment is not a primary media of concern at this site.
24
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5.4 TREATMENT SYSTEM COMPONENT PERFORMANCE
5.4.1 P&T SYSTEM
The P&T system has continued to perform as designed for the past 10 years and has been successful at
reducing the extent of the TCE plume, such that the area where TCE in groundwater exceeds MCLs is
limited to the source area and the area immediately downgradient of the source area. Given the remedial
progress made at the site (particularly resulting from the ISTT remediation in the source area), it is
unlikely that the treatment system will continue to operate in its current form for more than 1 or 2 years.
If longer term operation of the system is expected, the optimization review team would suggest significant
modifications to the P&T system. Therefore, further discussion of individual components of the current
system is not included herein. Potential options for a future P&T system, if needed, are discussed in
Section 6.4.2.
5.4.2 ISTT
About 80 percent of the vadose zone temperature sensors and about 50 percent of the saturated zone
temperature sensors achieved the target performance temperature goals, but 100 percent of the sensor
locations exceeded the minimum temperature goal of 60 degrees C. Consequently, performance
objectives were partially met. In general, temperatures within two of the ISTT areas (C and D) remained
below the target temperature until the system was modified with the introduction of steam-enhanced
heating in December 2010.
Confirmation soil sampling was performed in April 2011 and confirmation groundwater sampling was
performed in March, May and August 2011. Based on the results of these sampling events, the following
conclusions may be made: (1) considerable contaminant mass and concentration reduction was achieved
and (2) isolated areas of elevated TCE concentrations remain in the vadose zone. TCE concentrations in
groundwater remain above the MCL at 8 of 16 monitored locations measured in the last round of
confirmation sampling, with a maximum concentration of 78 (ig/L at well RW-5. Additional sampling is
likely needed to evaluate the full extent of contaminant rebound given the potentially increasing TCE
concentration trend at RW-05.
5.5 REGULATORY COMPLIANCE
No significant regulatory compliance issues were identified during the optimization review. The Second
Five-Year Review (EPA Region 1 - 2010) states that a small amount of contaminated groundwater by-
passing the source area extraction wells does not affect the protectiveness of the remedy because the
groundwater in the area is not being used for household or potable purposes and is not adversely affecting
environmental receptors. With respect to effluent from the P&T system, the Second Five-Year Review
(EPA Region 1-2010) states that there have been minor exceedences of the metals surface water
discharge limits in a small fraction of GWTF effluent samples (five arsenic, five lead, and two mercury
exceedences in 169 samples), but toxicity testing showed no adverse effects on the ecological receptors.
25
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5.6 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL
COSTS
The site team provided approximate O&M costs for a period from late 2011 to early 2012. The table
below summarizes these O&M costs pro-rated for an annual period, which sum to approximately
$345,600 per year.
Cost Category
Project Management
O&M Labor
Materials
Process Analytical
Groundwater Sampling and Analysis
Other Routine Costs
Non-Routine Costs
Utilities - Electric
Utilities - Gas
Total Costs
Estimated Annual Cost
$46,500
$122,000
$1,600
$45,000
$40,000
$3,800
$10,800
$75,000
$900
$345,600
The electric utilities cost is estimated is based on approximate annual electrical usage of 500,000 kWh
and an assumed electricity rate of approximately $0.15 per kWh. The gas utilities cost is estimated based
on approximate gas usage of 600 therms (building heat) and an assumed cost of approximately $1.50 per
therm.
These estimated annual O&M costs (less than $350,000 per year) are substantially lower than costs
reported in the Second Five-Year Review (EPA Region 1 - 2010), which pertain to the period when the
site was operated by the EPA. In the 5-year period from 2005 to 2009, the annual O&M costs ranged
from $717,000 to $854,000.
5.7 APPROXIMATE ENVIRONMENTAL FOOTPRINT ASSOCIATED WITH REMEDY
The following subsections describe the environmental footprint of the site remedies, considering the five
core elements of green remediation defined by the EPA (www.cluin.org/greenremediation).
5.7.1
ENERGY, AIR EMISSIONS AND GREENHOUSE GASES
The energy and air emissions footprints for the P&T remedy are dominated by the electricity usage for the
P&T remedy. Approximately 500,000 kWh of electricity is used per year, and more than 50 percent of
that use is the one 30kW UV lamp that continues to operate. Another 15 to 20 percent is for pumping
water from extraction wells or through the treatment plant. The remainder of the electricity usage is likely
associated with building lighting and ventilation and miscellaneous loads. Based on parameters provided
in the EPA document Methodology for Understanding and Reducing a Project's Environmental Footprint
(February 2012), the optimization review team estimates that the hydrogen peroxide, GAC use, waste
disposal, personnel transportation and materials transportation each likely contribute less than 1 percent of
the energy footprint and, therefore, are also likely small contributors to the air emissions footprints. The
natural gas used for heating the building likely contributes slightly more than Ipercent to the energy
footprint. In the future, efforts to reduce footprints for this core element would focus on reducing
electricity use.
26
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For comparison, the ISTT remedy used over 3.6 million kWh of electricity, representing the equivalent of
approximately 7 years of P&T operation.
5.7.2 WATER RESOURCES
The primary use of water associated with the remedy is the extraction, treatment and discharge of
impacted groundwater to Mill Pond. The extraction and discharge of groundwater does not likely
significantly alter the water resources in the area given that the extracted groundwater would likely have
discharged to the stream/pond system under natural conditions.
5.7.3 MATERIALS USAGE AND WASTE DISPOSAL
The primary materials usage is hydrogen peroxide and catalytic carbon materials use. Specific quantities
were not discussed but are anticipated to represent less than 5,000 pounds of refined materials per year.
Note that for this calculation, the water portion of the 20 percent hydrogen peroxide solution is not
included.
Waste disposal is primarily limited to iron sludge from the metals removal system. Disposal of
approximately 10 cubic yards of solids is required approximately once every 5 years.
5.7.4 LAND AND ECOSYSTEMS
The operating groundwater remedy does not disturb land and ecosystems. The space occupied by the
treatment plants may eventually be redeveloped and returned to beneficial use once the remedy is
complete.
5.8 SAFETY RECORD
The site team did not report any safety concerns or incidents.
27
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6.0 RECOMMENDATIONS
Several recommendations are provided in this section related to remedy effectiveness, cost control,
technical improvement and site closure strategy. Note that while the recommendations provide some
details to consider during implementation, the recommendations are not meant to replace other, more
comprehensive, planning documents such as work plans, sampling plans and QAPPs.
Cost estimates provided herein have levels of certainty comparable to those typically prepared for
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) FS reports (-30%
/ +50%), and these cost estimates have been prepared in a manner generally consistent with EPA 540-R-
00-002, A Guide to Developing and Documenting Cost Estimates During the Feasibility Study, July,
2000. The costs presented do not include potential costs associated with community or public relations
activities that may be conducted prior to field activities. The costs of these recommendations are
summarized in Tables 6-1. Table 6-2 summarizes potential effects of the recommendations on the
environmental footprint of the remedy.
The recommendations described below are inter-related, and an overall decision framework in the form of
a flowchart is illustrated on Figure 6-1 to illustrate those interrelationships. The flowchart begins with a
limited period of P&T operation that includes operation of extraction wells EW-S1 through EW-S3 plus
EW-4 (see Section 6.1.1), and potential outcomes are identified as "A" through "D" on Figure 6-1. An
alternative approach that does not include operation of extraction wells EW-S1 through EW-S3, and a
discussion of the advantages and disadvantages of that alternative approach, is presented in Section 6.1.2.
28
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Figure 6-1. Flow Chart Illustrating Suggested Decision Framework
For Up to One Year
• Operate EW-S1 to EW-S4
• Do not operate other EWs
• Increase monitoringto monthly at
selected locations
Establish shut-down criteriafor EW-Si to EW-S3 and for EW-S4:
Concentrations at extraction well(s) are below MCLs
- or-
Concentrations at extraction wells aredeclining and
concentrations upgradient are also declin ing
- or-
Concentrations at extraction wells are below threshold
concentrations thatthe site team establishes for performing
active remediation, based on acceptable risk to potential
receptors (i.e., risk-based criteria) and/or based on historical
dilution factors between extraction wells andm-onitoring
locations further downgradient
This would be an unexpected result re-
visitconceptual site model
Attempt to optimize current treatment
plantsincecontinued P&T operation
would be required
Shut-down criteria
met at EW-S4?
Perform direct push investigation
to delineate area targeted for
potential additional remediation
(likelyexcavation and disposal)
Shut-down criteria
met at EW-S1, EW-S2
andEW-S3 andsource
area concentrations
(RW-05) not
increasing?
Estimate cost of remediatingthe
targeted source area?
Feasible to remediate
remaining source?
Eliminate P&T
Continue monitoring
Reduces annual O&Mto
~$65,OOO/yr
Continue extraction at
EW-SI to EW-S3
Implement simplified
treatment system
Continue monitoring
Reduces annual O&M
to~$115,OOO/yr
Remediate remaining
source
Eliminate P&T
Continue monitoring
Up-front costs will be offset
by reduced O&M costs,
paybackperiod like!y<2 yrs
29
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6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS
6.1.1 CONTINUE P&T OPERATION (EW-S1 TO EW-S4), WITH MONTHLY MONITORING
OF SELECT WELLS, FOR UP To ONE YEAR
The optimization review team recommends continued operation of specific extraction wells (EW-S1
through EW-S4) and treatment with the existing system for up to 1 year while the system extracts limited
contaminant mass that may have migrated from the source area during the ISTT remedy and while the site
team establishes shutdown criteria for EW-S1 through EW-S4 (see Section 6.4.1). Currently EW-S4 is
operating and EW-S1 through EW-S3 will be re-started in the near future now that groundwater
temperatures have mostly recovered from the ISTT remediation. Operation of the other extraction wells is
not recommended. Extraction wells EW-M2, Gl, and G2 have already been turned off, and TCE
concentrations at EW-S5, EW-M1, and EW-M3 are sufficiently low that pumping is providing no
meaningful mass removal or plume control.
The optimization review team recommends more frequent (i.e., monthly) sampling of select wells in and
downgradient of the source area, for up to 1 year, to improve the understanding of site conditions between
the source area and EW-S4 following the ISTT remedy. The relatively fast groundwater flow velocity
between the source area and EW-S4 and the relatively short distance between the source area and EW-S4
suggests that meaningful changes in contaminant concentrations can occur on a monthly basis. The
optimization review team recommends monthly monitoring of the following wells for VOCs on an
interim basis (up to 1 year):
• RW-05
• EW-S1
• EW-S2
• EW-S3
• TW-31
• TW-12
• TW-24
• EW-S4
• EW-S5
P&T operation is currently planned, so the recommended P&T operation for up to 1 year would not
impact currently estimated costs for the next year. The more frequent monitoring that is recommended
will add cost of approximately $20,000, including deployment of the PDBs, laboratory analysis of field
and QA samples and data management. However, this recommendation is intended to provide data that
will shorten the time frame for active remediation and ultimately result in net cost savings, as described
below (see Section 6.2). The additional cost for increased monitoring frequency will be smaller if
meaningful trends are observed in less than 12 months.
Although sampling the selected wells on a monthly basis for 1 year is more expensive than sampling them
quarterly (for extraction wells) or semi-annually (for monitoring wells) for 1 year as currently planned,
the optimization review team believes that meaningful trends will become apparent in this area over the
course of months under monthly sampling, whereas it might take several years to discern the trends with
the current quarterly and semi-annual sampling. Given that these trends will be critical in determining a
remedial path forward and may play a significant role in permanently discontinuing P&T operation (a key
objective in the site exit strategy), the optimization review team believes that the additional cost is
merited.
30
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The interim monthly sampling should continue for 1 year or less if meaningful trends are identified and
can be used for decision making. If meaningful trends are not established after 1 year of monthly
sampling, then the current monitoring frequency of quarterly for extraction wells and semi-annually for
monitoring wells should resume. Section 6.4 discusses how the data from this monitoring can be used to
make decisions regarding the remedy that will improve the opportunities for eliminating active
remediation in the long-term.
6.1.2 ALTERNATIVE APPROACH - Do NOT OPERATE EW-S1 TO EW-S3 DURING
INITIAL MONITORING PERIOD
With respect to the recommendation described in Section 6.1.1, the site team could consider an alternative
approach in which extraction wells EW-S1 through EW-S3 are not returned to operating status during the
initial monitoring period. EW-S4 would continue to operate, and the GTWF would still be needed. This
approach might entirely eliminate the re-start of those three extraction wells if the shutdown criteria for
EW-S1 through EW-S3 and EW-S4 can all be met, resulting in Outcome "A" on Figure 6-1. However,
there is additional risk in pursuing this alternative because there is a possibility that the shutdown
criterion for EW-S4 (see Section 6.4.1) might not be met in the absence of extraction at EW-S1 through
EW-S3. If that occurred, it would eliminate the potential to achieve outcomes "A", "B" or "C" on Figure
6-1 in the short-term (i.e., it would delay potential elimination or substantial streamlining of the current
GWTF), and would complicate subsequent decisions. The decision framework illustrated on Figure 6-1
allows for a more straightforward decision-making process.
6.2 RECOMMENDATIONS TO REDUCE COSTS
6.2.1 ESTIMATED COST SAVINGS FOR POTENTIAL SCENARIOS
The optimization review team has not provided specific recommendations to reduce costs for operating
the P&T system in its current form (for example, treatment plant upgrades) because continued P&T
operation for more than 1 year (at most) is considered unlikely. However, the recommendations described
in Section 6.1 (i.e., extraction for up to 1 year with monthly monitoring) are expected to result in one of
several potential outcomes (labels "A", "B", and "C" on Figure 6-1) that will have much lower long-term
costs relative to the current P&T system. Possible outcomes and associated estimates for potential costs
savings include the following:
• Outcome "A " on Figure 6-1. A likely potential outcome is that P&T operations at this site will
be terminated within 1 year (and perhaps much less than 1 year). If that occurs, the current cost of
$345,600 per year would likely be reduced to approximately $65,000 per year (assuming $25,000
per year for project management and $40,000 per year groundwater monitoring). Thus, cost
would be reduced by approximately $280,000 per year for this scenario versus the current P&T
system.
• Outcome "B " on Figure 6-1. Another potential outcome is that P&T extraction can be limited to
source area wells EW-S1 through EW-S3 within 1 year, and the associated flow rate would allow
for a simpler treatment approach. The current cost of $345,600 per year would likely be reduced
to approximately $115,000 per year (assuming $65,000 per year for the scenario with no P&T
described above, plus an additional $50,000 per year associated with management and operation
of a smaller P&T system as detailed in Section 6.4.2). Thus, cost would be reduced by
approximately $230,000 per year for this scenario versus the current P&T system. It is expected
that treatment plant modifications for this scenario would require up-front costs of approximately
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$50,000, with payback achieved in much less than 1 year.
• Outcome "C " on Figure 6-1. Another potential outcome is that additional source area
remediation (likely to consist of excavation and disposal) may be required in a targeted area to
enable the complete shutdown of P&T operations. Based on the size of the targeted area, the up-
front costs might range from less than $100,000 to $500,000 or more, as discussed in Section
6.4.2. These up-front costs would be offset by annual savings of approximately $280,000 per
year that would result from complete termination of P&T operations (as discussed in Outcome
"A" above). Thus, the payback period might range from less than 1 year to as much as several
years for this scenario.
• Outcome "D " on Figure 6-1. An unexpected outcome would be that downgradient extraction
well EW-S4 needs to continue operating because the remaining source area is sufficiently strong
and the capture provided by EW-S1 through EW-S3 is not sufficient. If this outcome occurs after
the first year, it would then be appropriate to re-visit the CSM, and to optimize the current GWTF
since continued P&T operation would be required.
6.2.2 DELAY TREATMENT PLANT UPGRADES
For the likely outcomes described in Section 6.2.1, the current treatment system would not be operated in
its current form for more than 1 year (and perhaps much less than 1 year). Therefore, the optimization
review team recommends that any currently planned upgrades to the P&T system be delayed if at all
possible. Any such upgrades that can ultimately be avoided, by delaying the upgrades until the treatment
plant is eliminated, would result in additional costs savings (not quantified by the optimization review
team).
6.3 RECOMMENDATIONS FOR TECHNICAL IMPROVEMENT
No recommendations are provided for technical improvement.
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT
The monthly sampling of select wells (described in Section 6.1) will provide critical information for
evaluating remedy effectiveness and determining an appropriate path to site closure in a timely manner. A
suggested decision framework in the form of a flowchart (Figure 6-1) illustrates how decisions on
terminating the P&T activities and or conducting additional investigation and remediation of the source
area can be made based on data collected over the next year in conjunction with shutdown criteria.
Recommendations associated with this suggested decision framework are provided below.
6.4.1 DEVELOP SHUTDOWN CRITERIA FOR EW-S1 THROUGH EW-S4
The optimization review team recommends that the EPA and MassDEP collectively determine
appropriate shutdown criteria for the remaining extraction wells. Different parties may have different
perspectives on appropriate shutdown criteria for operating extraction wells. Two potential perspectives
are provided below for consideration. Other perspectives might also be considered.
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• One perspective is to select MCLs as the shutdown criteria for operating extraction wells. This
perspective is based on the premise that active remediation with a selected remedy is appropriate
until cleanup criteria are met. This perspective provides relative certainty that the contaminant
concentrations downgradient of the extraction wells will remain below MCLs in the absence of
continued pumping. This perspective also has the benefit of being consistent with the most
conservative interpretations of policy.
• A second perspective is to select some value above MCLs as the shutdown criteria for extraction
wells (in conjunction with continued monitoring) if risks to receptors are adequately low and or
estimates of attenuation indicate that concentrations will be acceptably low (for example, below
MCLs) within a specified distance from the area that remains above MCLs. This perspective is
premised on recognition of the high cost and resource use of continued extraction and the limited
benefit of extracting low level concentrations, as illustrated by the following three key attributes:
o For settings such as this site, continued extraction of low level concentrations contributes
little to plume stability because of the dilution, dispersion and attenuation of low level
concentrations that would occur over a short distance from the extraction wells, even in
the absence of pumping.
o Extraction of low level concentrations involves low levels of mass removal.
o Extraction at this site (even at EW-S1 through EW-S3) occurs downgradient of a source
and does not meaningfully decrease the time frame for source reduction.
Adopting this perspective, however, involves establishing the definition of "low level
concentrations" and "short distances" downgradient of extraction wells. An evaluation of
contaminant transport coupled with regulatory interpretation could be used to establish these
definitions. One approach might be to use historically observed attenuation factors from the
period before active remediation. For example, prior to remedy pumping, groundwater TCE
concentrations in the source area of 40,000 (ig/L (for example, EW-S2 from April 2000) resulted
in groundwater TCE concentrations of 6,600 (ig/L immediately upgradient of Mill Pond (for
example, EW-S5 from April 2000). This translates to an attenuation factor of approximately 6.
The groundwater TCE concentration downgradient of Mill Pond (EW-M1) during the same time
frame was 870 (ig/L. This translates to an attenuation factor of over 7 for TCE in groundwater
between the upgradient and downgradient edges of Mill Pond. Using these attenuation factors, a
TCE concentration of 30 (ig/L in the source area would result in a TCE concentration of 5 (ig/L at
EW-S4 under non-pumping conditions and a concentration below 1 (ig/L at EW-M1.
Additionally, extraction of 30 (ig/L at 3 gpm by EW-S1 through EW-S3 would remove
approximately 0.4 pounds of TCE per year that would otherwise attenuate before reaching EW-
S4. Based on this analysis, one option might be to discontinue pumping from EW-S1 through
EW-S3 when TCE concentrations in these wells are no higher than 30 (ig/L. Applying the same
logic, a TCE concentration at EW-S4 of 35 (ig/L would attenuate to 5 (ig/L before reaching the
location of EW-M1. Therefore, an alternate option would be to discontinue pumping from EW-S4
when the TCE concentration at this well is approximately 35 (ig/L.
• Another potential approach is to consider shutting down the source area extraction wells (EW-S 1
through EW-S3) if the extraction wells have groundwater concentrations above the MCLs, but
monitoring indicates declining concentrations over time at these extraction wells, and the
concentrations at the extraction wells are sufficiently low that it is unlikely that terminating
33
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extraction will cause increases in concentrations further downgradient that would be high enough
to be of concern.
The monthly sampling suggested in Section 6.1 should help the site team better understand the changes in
concentration as contamination migrates from the source area toward Mill Pond. Given a hydraulic
gradient of approximately 0.06 ft per ft, a hydraulic conductivity of approximately 50 ft per day, an
assumed effective porosity of 0.25, and minimal retardation, the contaminant transport velocity in the area
is approximately 10 ft per day. For the distance of approximately 500 ft between the source area and EW-
S4, observable changes in TCE concentrations (if any) resulting from the re-start of EW-S1 through EW-
SSwill likely be apparent within 2 to 3 months.
A potential approach for addressing these shutdown criteria is indicated on Figure 6-1. However,
determining the shutdown criteria for the extraction wells is not solely a technical decision, thus the
optimization review team cannot provide more specific recommendations or opinions. If there is concern
or uncertainty about selecting shutdown criteria, the EPA and MassDEP may decide to devise a
contingency plan that allows extraction well operation to resume after shutdown if concentrations at pre-
determined monitoring points increase above a pre-determined action level. The optimization review team
believes that the primary effort involved in implementing this recommendation involves meetings
between the EPA and MassDEP. Limited contractor support for these meetings might cost up to $10,000.
6.4.2 CONSIDER ADDITIONAL REMEDIAL OPTIONS FOR THE SOURCE AREA
The confirmation soil sampling from CSB-10 (5,600 ng/kg between 23 and 25 ft bgs) and CSB-13 (7,000
Hg/kg between 3 to 5 ft bgs) suggests that contamination is still present in vadose zone soil that has the
potential to result in TCE groundwater contamination orders of magnitude above MCLs. The August
2011 TCE concentration of 78 (ig/L in RW-05, further suggests the potential that a source of groundwater
contamination remains in this area. It is unclear, however, if these observed soil and groundwater
concentrations are isolated and of insufficient mass to serve as a source for an extensive TCE plume
above MCLs, or if they merit further attention. The monthly sampling suggested in Section 6.1, in
conjunction with the re-start of extraction at EW-S1 through EW-S3, should help the site team evaluate
the significance of this remaining contamination. Sampling of RW-05, which is co-located with the
observed vadose zone contamination, might help identify maximum source area concentrations, but this
well might be relatively isolated. Sampling of EW-S Ithrough EW-S3 while they operate as extraction
wells should provide a representative concentration of TCE that would otherwise migrate from the source
area under current conditions (i.e., subsequent to the mass reduction provided by the ISTT remediation).
If the TCE concentrations at RW-05, EW-S1, EW-S2, and EW-S3collectively indicate that continued
extraction is needed (for example, concentrations at the extraction wells are higher than the shutdown
criteria established according to the recommendation provided above and or TCE concentrations at RW-
05 show an increasing trend), the optimization review team suggests conducting a direct-push technology
(DPT)-based high-resolution investigation of the approximately 50-ft by 50-ft area around CSB-10, CSB-
13 and RW-05 to collect soil samples for determining the extent of vadose zone contamination. This
investigation is only recommended if the interim monthly monitoring coupled with the re-start of EW-S 1
through EW-S3 (suggested above) indicates that the source area extraction wells need to continue
operation in the long-term. Otherwise, this investigation would not be performed. If this investigation is
performed, collecting soil samples via DPT at 10-ft grid spacing and at 3 depth intervals would provide a
high degree of resolution of the source extent and magnitude. The optimization review team estimates that
this high-resolution site characterization (HRSC) type approach might cost on the order of $40,000 for
planning, field work, laboratory analysis and limited reporting. The site team could alternatively opt for a
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mobile laboratory and a dynamic work strategy if such an approach can be performed more cost
effectively.
The results of the HRSC investigation (if needed) should give the site team a thorough understanding of
the extent of residual contamination. The site team could then evaluate if a second attempt at source
removal (i.e., polishing) is appropriate or if continued containment by operating EW-S1, through EW-S3
is preferred. The method of treatment of the groundwater extracted from EW-S1 through EW-S3 would
be dependent on the status of EW-S4. If EW-S4 continues to operate, the costs noted in Section 5.6 of this
report would likely be expected. However, if EW-S4 is no longer operating, the total extraction rate
requiring treatment would be approximately 3 gpm. The extracted water from EW-S1 through EW-S3
could then be treated by small GAC vessels, and because these wells are located several hundred feet
from Mill Pond, the treated water could be then reinjected into the subsurface immediately downgradient
of the extraction wells. Treatment for arsenic should not be required in that case. This would result in a
much less costly system with minimal operator attention required (discussed below).
The cost of remediating the vadose zone contamination would be highly dependent on the volume to be
treated and the distribution of the contamination. Because ISTT with vapor extraction has already been
implemented in the area, the optimization team would not suggest use of an SVE system. The most
appropriate option might be excavation with off-site disposal, since ISCO was previously pilot tested and
was reportedly not very effective. Assuming an estimated maximum volume of 2,800 cubic yards that
might merit remediation (50 ft by 50 ft in area and 30 ft deep) and an estimated cost of $200 per cubic
yard, remediation costs might range as high as $560,000. However, if the HRSC investigation refined the
volume meriting remediation, the costs would be reduced. For instance, an area of 30 ft by 20 ft and 20 ft
deep (i.e., approximately 450 cubic yards) might require less than $100,000 to remediate.
If groundwater extraction from EW-S1 through EW-S3 were to occur in the absence of extraction from
EW-S4, approximately $50,000 in up-front costs might be required to furnish and install bag filters, two
500-lb GAC units, install a small infiltration gallery and modify controls as appropriate. The bag filters
and GAC units would be located after the current metals removal system so that some of the dissolved
iron in the extracted water can be removed prior to GAC treatment. The multi-media pressure filters,
UVOx, and catalytic GAC in the current system would be bypassed. The additional costs for operating the
simplified treatment system (i.e., above and beyond the management and monitoring costs for a
"monitoring only" remedy) would be under $50,000 per year assuming the following:
• $20,000 per year for one 4-hour system check per week, plus occasional longer visits for
additional maintenance;
• $6,500 per year for electrical power (assume 5 kW) to utilized parts of the building;
• Under $2,000 for quarterly sampling of the influent, mid-GAC, and effluent;
• $12,000 per year for additional project management, technical support, and minimal reporting;
and
• Under $10,000 per year for miscellaneous project needs.
There is too much uncertainty at present to evaluate either option in more detail. Depending on the results
from the monthly monitoring recommended in Section 6.1, additional remediation may not even be
appropriate.
6.4.3 POTENTIAL LONG-TERM OPTIONS FOR EW-S4
The optimization review team does not anticipate long-term pumping from EW-S4 because TCE
concentrations were low prior to the ISTT remedy, and should decrease below MCLs now that the ISTT
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remedy has been implemented and EW-S1 through EW-S3 can control the large majority of any
remaining contamination once they are operating. If contamination at EW-S4 remains significantly above
MCLs for more than 12 months after operation of EW-S1 through EW-S3 begins, then the CSM will need
to be revisited. The optimization review team would suggest focusing on controlling plume migration at
the source area where flow rates are low and groundwater extraction is several hundred feet from Mill
Pond. This would allow the GWTF to be simplified as discussed in the previous section.
Other options for the GWTF would be to replace the multimedia filters with bag filters and to replace the
UVOx system with GAC or air stripping. The capital costs of making these changes would likely exceed
$100,000. Given the improving conditions at the site and the likelihood that EW-S4 can be taken offline
in a few years or less, it is unclear if there would be complete payback before shutdown of EW-S4 occurs.
6.5 RECOMMENDATIONS RELATED TO GREEN REMEDIATION
Given the focus on site closure (i.e., the expectation that the current P&T system will only operate for a
short amount of time), no opportunities for footprint reduction regarding the current P&T system (for
example, treatment plant upgrades) were contemplated. However, to the extent P&T operations are
terminated or significantly scaled back within a year or less (which is likely based on the discussion
above), remedy footprints will be reduced accordingly. The actual footprint reductions will depend on
which of the potential outcomes on the decision flowchart presented on Figure 6-1 actually occurs (i.e.,
similar to the potential cost savings).
6.6 SUGGESTED APPROACH TO IMPLEMENTING RECOMMENDATIONS
The optimization team recommends implementing the recommendations in Section 6.1 and Section 6.4.1.
The subsequent recommendations in Section 6.4 would be contingent on the results of those activities, as
per the suggested decision framework on Figure 6-1. Cost information for the recommendations is
provided in Table 6-1, and potential impacts on environmental footprints from the recommendations are
provided in Table 6-2.
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Table 6-1. Cost Summary Table
Recommendation
6.1.1 CONTINUE P&T
OPERATION (EW-1 TO EW-
4), WITH MONTHLY
MONITORING OF SELECT
WELLS, FOR UP TO ONE
YEAR
6.1.2 ALTERNATIVE
APPROACH - DO NOT
OPERATE EW-S1 TO EW-S3
DURING INITIAL
MONITORING PERIOD
6.2.1 ESTIMATED COST
SAVINGS FOR POTENTIAL
SCENARIOS**
6.2.2 DELAY
TREATMENT PLANT
UPGRADES
6.4.1 DEVELOP
SHUTDOWN CRITERIA
FOR EW-S1THROUGH EW-
S4
6.4.2 CONSIDER
REMEDIAL OPTIONS FOR
THE SOURCE AREA
6.4.3 POTENTIAL LONG-
TERM OPTIONS OF
CONTINUED EXTRACTION
AT EW-S4 IS NEEDED
Category
Effectiveness
Effectiveness
Cost
Reduction
Cost
Reduction
Site Closure
Site Closure
Site Closure
Additional Capital
Cost
$20,000*
Change in Annual
Cost
$0
Change in Life-
Cycle Cost
(10 yrs, 3%
discount rate)
$20,000*
Not quantified, but would save some short-term cost if
implemented as an alternative to recommendation 6.1.1 (but
would also increase risk of not achieving shutdown criteria at
EW-S4, which could increase long-term cost)
Outcome "A"
$0
Outcome "B"
$50,000
Outcome "C"
***
Outcome "A"
$(280,000)
Outcome "B"
$(230,000)
Outcome "C"
$(280,000)
Outcome "A"
$(2,380,000)
Outcome "B"
$(1,905,000)
Outcome "C"
***
Not quantified
$10,000
$0
$10,000
Costs subject to uncertainty. Refer to report text Section 6.4.2.
No estimates of costs or cost savings.
*This is the additional cost for the more frequent monitoring at selected wells, The P&T operation is currently
planned, so the recommended P&T for up to 1 year does not impact estimated costs for that year.
** For recommendation 6.1.2, the 10-year period is assumed to start after the current P&T operations for up to 1
year that are inherent in recommendation 6.1.1.
***Up-front costs likely to be on the order of $100,000 to $500,000, with payback from annual savings within a few
years.
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Table 6-2. Summary of Effects on Environmental Footprint
Recommendation
Effect on Environmental Footprint
6.1.1 CONTINUE P&T OPERATION (EW-S1 to EW-
S4), WITH MONTHLY MONITORING OF SELECT
WELLS, FOR UP TO 1 YEAR
Implementation of this recommendation is expected
to directly increase the environmental footprint of
the in all green remediation categories (due to
increased monitoring). However, monitoring with
PDBs has a relatively low footprint, and the
information gathered from implementing this
recommendation should facilitate faster shutdown
or modification of the P&T system, which would
substantially reduce or eliminate the long-term
environmental footprint.
6.1.2 ALTERNATIVE APPROACH - DO NOT
OPERATE EW-S1 TO EW-S3 DURING INITIAL
MONITORING PERIOD
By eliminating extraction at EW-S1 through EW-S3
for up to 1 year, some reduction in the
environmental footprint might be achieved (i.e., due
to less electricity use). However, this alternative
would also increase risk of not achieving shutdown
criteria at EW-S4, which could increase the
environmental footprint in the long-term.
6.2.1 ESTIMATED COST SAVINGS FOR
POTENTIAL SCENARIOS**
To the extent P&T operations are terminated or
significantly scaled back within 1 year or less
(which is likely) remedy footprints will be reduced
accordingly. The actual footprint reductions will
depend on which of the potential outcomes on the
decision flowchart presented on Figure 6-1 actually
occurs (i.e., similar to the potential cost savings).
6.2.2 DELAY TREATMENT PLANT UPGRADES
To the extent improvements to the GWTF can be
avoided, there will be reductions in the
transportation of materials, equipment, and
personnel required for implementing those
upgrades.
6.4.1 DEVELOP SHUTDOWN CRITERIA FOR EW-
S1THROUGHEW-S4
There is no meaningful environmental footprint
associated with this recommendation, but
developing the criteria will help avoid the
environmental footprint of potentially unnecessary
future P&T system operation.
6.4.2 CONSIDER REMEDIAL OPTIONS FOR THE
SOURCE AREA
If deemed appropriate, targeted aggressive
remediation of remaining source material would
likely result in a higher environmental footprint in
the short term, but would likely reduce the overall
footprint of the remedy by reducing the time frame
or eliminating the need for P&T operation.
If P&T system operation continues but the system is
modified, the environmental footprint would be
substantially reduced both due to the type of
treatment provided and the smaller volume of water
requiring treatment.
6.4.3 POTENTIAL LONG-TERM OPTIONS OF
CONTINUED EXTRACTION AT EW-S4 IS NEEDED
The options discussed in this recommendation
would result in an overall reduction in the
environmental footprint.
-------
ATTACHMENT A
-------
^g^rJ !'•:
:
3C
iUiJ Groveland Station No. 1
Si W
Groveland Station No. 2
Site Boundary (OU 1)
IK
-:A p"- !K 1'--7 <^
:
Valley Manufactured Jp..- South
Products/Groveland Resources W Groveland
I
GROVELAND WELLS SITE
GROVELAND, MA
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978)683-0891
www.nobisengineering.com
-------
S3
SOURCE: COM. 1SW
Nobis Engijtieeruig, Inc.
585 Middlesex Street
Lowell. MA 01851
Tel (878) 883-OB91
Pal (878) 863-0866
TTWW. aobi s eaginccring, com
FIGURE 4
VALLEY/GRC BUILDING DETAILS
GROVEUWD WELLS
GROVELAND, MASSACHUSETTS
PROJECT NO. 80053 DATE:
MAY 2010
-------
Boring
Location
AD-01
AD-02
AD-02
AD-04
E-01
E-02
E-02
E-03
E-10
E-21
E-21
E-34
E-34
E-35
E^2
E^3
E^6
E^7
E^8
E^9
E-53
E-54
E-54
E-56
E-60
E-61
E-61
E-62
E-62
E-63
E-65
E-65
RW-01
RW-03
RW-05
RW-06
RW-08
RW-10
T-16
T-16
Start
Depth
9
7
9
8
0
7
10
9
9
6
9
7
9
10
9
9
4)
4J
s|
0
e|
0
1
9
5
1
5
10
5
8
3
5
9
8
1
3
6
9
8
8
10
End
Depth
10
8
10
9
1
8
11
10
10
7
10
8
10
11
10
10
s|
5
4
1
?|
1
2|
10
6
2
6
11
6
9
4|
7
10
9 1
2
4
7
10
9
9
11
TCE
1800
210
2 J
5 U
6 U
7 U
56 J
8 U
1200 U
8
3 J
5 U
5 U
5 U
2 J
4600
20000 D
2800
47
8
140
540
26
5 U
5 J
6
250 U
5 U
18
5 U
4 J
0 J
0 J
82
940
11000
3 J
2 BJ
6 U
150
14
Sample
Date
7/29/2009
7/29/2009
7/29/2009
7/30/2009
4/6/2010
3/30/2010
3/30/2010
3/4/2010
3/22/2010
3/4/2010
3/4/2010
3/4/2010
3/4/2010
3/9/2010
3/25/2010
3/17/2010
4/2/2010
4/12/2010
3/29/2010
3/25/2010
3/25/2010
4/7/2010
3/29/2010
3/29/2010
3/31/2010
3/31/2010
3/31/2010
3/31/2010
3/16/2010
3/16/2010
3/16/2010
3/3/2010
3/3/2010
8/4/2009
8/4/2009
8/5/2009
8/3/2009
8/6/2009
8/6/2009
3/22/2010
3/22/2010
•— — - — ____
—
— _
Legend
TCE RESULTS
0-11 ft bgs (|jg/kg)
O <77
O 77 - 500
• >500
Multiple samples collected
within Figure depth range.
Thermal Treatment Area
GR°UNDWATER To
62 WA^.I^TME
Notes:
1. The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
D - Concentration is reported from a dilution of the sample.
B - Analyte detected in labroratory blank.
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
BASELINE TRICHLOROETHENE RESULTS
IN SOIL-0-11 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Boring
Location
AD-01
AD-01
AD-02
AD-03
AD-03
AD-03
AD-04
AD-04
E-10
E-10
E-12
E-12
E-18
E-23
E-26
E-26
E-26
E-27
E-43
E-44
E-44
E-46
E-46
E-49
E-53
E-57
RW-02
RW-02
RW-04
RW-05
IRW-06
RW-07
RW-08
RW-09
Start
Depth
13
19
13
11
13
19
13
17
11
13
14
19
18
19
15
20
25
16
18
11
12
15
25
18
12
11
14
18
18
23
18
18
14
14
End
Depth
14
20
14
12
14
20
14
18
12
14
15
20
19
20
16
21
26
17
19
12
13
16
26
19
13
12
15
19
20
24
19
19
15
15
TCE
6 U
11
1 J
5 U
5 U
5 U
6 U
5 U
350 U
120
6 U
1400
155 J
5 U
5 J
160
38
1900
1700
410
140 J
10
360
62
6
5 U
3 BJ
9 B
6 U
7400
52
6 U
220 B
5 U
Sample
Date
7/29/2009
7/29/2009
7/29/2009
7/29/2009
7/29/2009
7/29/2009
7/30/2009
7/30/2009
8/5/2009
8/5/2009
7/30/2009
8/5/2009
8/3/2009
8/6/2009
8/4/2009
3/16/2010
3/16/2010
3/23/2010
3/17/2010
3/17/2010
3/16/2010
3/22/2010
3/22/2010
3/23/2010
3/29/2010
3/29/2010
3/8/2010
4/13/2010
4/2/2010
4/12/2010
4/12/2010
4/7/2010
3/25/2010
3/30/2010
"~~-— — .
"
Legend
TCE RESULTS
11-26 ft bgs
O <77
O 77 - 500
• >500
Multiple samples collected
within Figure depth range.
Thermal Treatment Area
Note:
1. The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
B - Analyte detected in labroratory blank.
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 4-2
BASELINE TRICHLOROETHENE RESULTS
IN SOIL- 11-26 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
•
:
8/4/2009
8/4/2009
8/4/2009
7/30/2009
3/2/2010
3/2/2010
8/5/2009
8/3/2009
8/4/2009
8/6/2009
3/16/2010
3/17/2010
3/30/2010
3/8/2010
4/6/2010
4/13/2010
4/2/2010
4/12/2010
3/5/2010
3/2/2010
Legend
TCE RESULTS
26-45 ft bgs
• <77
O 77 - 500
• >500
Multiple samples collected
within Figure depth range.
Thermal Treatment Area
Notes:
1. The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
B - Analyte detected in labroratory blank.
0 20 40
^
Feet
1 inch = 40 feet
80
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
BASELINE TRICHLOROETHENE RESULTS
IN SOIL - 26-45 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Well
Location
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-11A
TW-15
TW-18
TW-19
TW-23
TW-26
TW-30
TW-31
TW-33
TW-40
TW-42
TW-43
TW-44D
TW-47
TW-48
TW-9
IOC
Results
(M9/I)
5 U
15
11000 D
290 D
11000 D
5 U
83
52
4 J
10
390 D
1 J
5JB
43 B
10 B
78 B
300 B
38 B
1 JB
9 B
2 JB
5 U
96000 DB
18000 DB
1200 DB
8 B
150 B
380 B
Sample
Date
8/25/2009
8/25/2009
8/26/2009
8/24/2009
8/26/2009
8/25/2009
8/25/2009
8/26/2009
8/25/2009
8/26/2009
8/26/2009
8/26/2009
6/30/2009
6/29/2009
6/30/2009
6/30/2009
6/30/2009
6/30/2009
7/1/2009
6/30/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
6/29/2009
6/30/2009
;
Legend
TCE RESULTS (pg/l)
^ <5
-^ 5-200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for TCE in groundwater is 5 u§/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
D - Concentration is reported from a dilution of the sample.
B - Analyte detected in labroratory blank.
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 4-4
BASELINE TRICHLOROETHENE
RESULTS IN GROUNDWATER
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
E
oti
O
o
CL
OT
O
CL
-------
Horizontal Scale:
1" = 60'
Vertical Scale
1" = 60'
-a
x
"
Q
W
O
3
"5
Q
o
o
00
CD
T3
o
o
A
North
100 -i
50 -
o-
-50-
'•:-:'.:.:'Sand & Gra I •.'.':.••''•'•••/
A'
South
i- 100
- 50
-100-1
Notes
1. Location of Cross Section A-A' shown on Figures 3-1.
2. The groundwater samples collected from ERT-09 was paired with a field duplicate;
the posted value is an average.
3. Monitoring well and extraction well data collected in Fall 2010.
4. All concentrations in |jg/L.
5. EW-M1 was not operating on the day water level data was collected.
6. TCE - Trichloroethylene
7. NS - Not Sampled
- 0
- -50
I--100
Legend
Isoconcentration
Approximate Groundwater Elevation October 28, 2010
Well screened interval with TCE concentration depicted.
ISTT Treatment Area
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA
(978) 683-0891
www.nobisengineering.com
FIGURE 6-2
CROSS-SECTION A - A' &
TCE ISOCONTOURS-FALL 2010
GROVE LAND WELLS
GROVELAND, MASSACHUSETTS
PREPARED BY: AR
PROJECT NO. 80012
CHECKED BY: DL
DATE: JANUARY 2011
-------
...
•
^
'
-
•.
•
-
.
•
Notes
1. The current limits of Mill Pond are typically smaller than depicted, and are subject
to seasonal fluctuations.
2. TCE concentrations represent data collected during Fall 2010 sampling events.
3. NS is Not Sampled.
4. Values with a "U" (i.e. O.SU) indicate that TCE was not- detected, at or above the concentration shown.
5. Source area "RW" wells not included in OU1 Fall 2010 monitoring. Values shown for source area "RW
series wells were obtained from ISTT Remedial Action routine monitoring data (October 2010).
The maximum TCE concentration observed during October 2010 ISTT Remedial Action
Routine monitoring was 470 pg/L.
108
GROUNDWATER EXTRACTION AND TREATMENT FACILITY
WASHINGTON ST.
Legend
DEQE-8
0.3
EW-M1
6.4
Overburden Monitoring Well with _ EW-M3
TCE Concentration ug/L (Fall 2010) (' "25
Overburden Extraction Well with ^ 108
TCE Concentration ug/L (Fall 2010) - '
Bedrock Extraction Well with
TCE Concentration ug/L (Fall 2010)
Bedrock Monitoring Well with
TCE Concentration ug/L (Fall 2010)
APPROXIMATE SCALE
240 120 0 240
Feet
INSET SCALE
Estimated Extent of Overburden TCE Concentrations
Exeeding MCL in Fall 2010
50 25 0
50
Feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 4
OVERBURDEN TCE PLUME
FALL 2010
GROVE LAND WELLS
GROVELAND. MASSACHUSETTS
PREPARED BY: AR
PROJECT NO. 81015
CHECKED BY: DB
DATE: 12/21/2011
-------
ERT-16
ERT-13 ^
ERT-11
DEQE-6
TDEQE 4-2
EW-M3
®
EW-M2
G2f iME-IOD* "
'EW-M1-. «.
"DEQE13D
Pond
DEQE-7
EW-S5®
104
WASHINGTON STREET
Groundwater
Treatment Facility
Valley Manufacturing
Building
\\
SEE INSET .
Legend
DEQE-8
EW-M1
•
1
I
3- Overburden Monitoring Well
5 Management of Mitigation Extraction Well
Extent of TCE Overburden Plume < 5 ug/L
Prior to System Startup in 2000
^ Extent of TCE Overburden Plume> 5 ug/L in 2006
^ Extent of TCE Overburden Plume < 5 ug/L in 2010
APPROXIMATE SCALE
190 95 0 190
Feet
INSET SCALE
Notes:
1. Aerial photograph provided by MassGIS.
50 25 0
50
Feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 2-1
INSET
OVERBURDEN GROUNDWATER
TRICHLOROETHENE PLUME
2000, 2006, AND 2010
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: LS
DATE: 8/18/2011
-------
Notes
1. The current limits at Mill Pond are typically smaller than depicted, and are subject
to seasonal fluctuations
2. TCE concentrations shown are for (he moat recent sapHng data available: Fall 2009
for all extraction wells and all monitoring wells located outside the Source Area:
Summer 2009 (or all monitoring welts located within trie Source Area ("RW wells).
ERT-9
2.8
EW-M3
16
Legend
Existing Bedrock Monitoring Well
» Used in 2009 Monitor ing with TCE
Concaniration (pg/L)
Existing Extraction Well
' with TCE conentratlon (p^L)
APPROXIMATE SCALE
175 87.5 0
175
JPeet
NobA Ej>gi[iiHiflng. tnc
(9/3) 6KMO1
FIGURE 7
BEDROCK GROUNDWATER
TCE CONCENTRATIONS - FALL 2009
GROVELAND WELLS
GROVELAND, MASSACHUSETTS
PREPARED BY AR
PROJECT NO. 80053
CHECKED BY DL
-------
•
' :
'
>
' :
-
•
GROVELAND WELL
STATION #1
JOHNSON
CREEK
FAC L TY D SCHARGE LOCAT ON
GROVELAND WELL
STATION #2
(INACTIVE)
GROUNDWATER TREATMENT FACILITY
VALLEY MANUFACTURING BUILDING
WASHINGTON ST
Legend
® Existing Extraction Well
• Public Water Supply Well
Notes
1. The current limits of Mill Pond are typically smaller than depicted,
and are subject to seasonal fluctuations.
APPROXIMATE SCALE
0 115 230
460
Feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA
(978) 683-0891
www.nobisengineering.com
FIGURE 2
OPERABLE UNIT 1 SITE PLAN
GROVE LAND WELLS
GROVELAND, MASSACHUSETTS
PREPARED BY: AR
PROJECT NO. 81015
CHECKED BY: DB
DATE: 12/21/2011
-------
In Situ Treatment Zones
| | ISTT Area A, 0 to 45 feet below ground surface (8,460 ft2)
| | ISTT Area B, 0 to 25 feet below ground surface (910 ft2)
| | ISTT Area C, 0 to 10 feet below ground surface (2,950 ft2)
| | ISTT Area D, 0 to 10 feet below ground surface (2,370 ft2)
20 40
80
Feet
1 inch = 60 feet
Notes:
1. Aerial photograph provided by MassGIS
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
IN SITU THERMAL TREATMENT AREAS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: LS
DATE: 8/18/2011
-------
Well
Location
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
TW-9
TW-11A
TW-15
TW-18
TW-19
TW-23
TW-26
TW-30
TW-31
TW-33
TWMO
TWM2
TWM3
TW^t4D
TWM7
TWM8
CIS-1,2-DCE
Results (fjg/l)
5 U
3 J
260 DJ
57
325 DJ
5 U
37
5 J
5 U
3 J
160
5 U
5 U
340
5 U
1~7|
2 J
20
160
8
5 U
5 U
5 U
5 U
1000 U
170
200 D
1 J
120
Sample
Date
8/25/2009
8/25/2009
8/26/2009
8/24/2009
8/26/2009
8/25/2009
8/25/2009
8/26/2009
8/25/2009
8/26/2009
8/26/2009
8/26/2009
6/30/2009
6/30/2009
6/30/2009
6/29/2009
6/30/2009
6/30/2009
6/30/2009
6/30/2009
7/1/2009
6/30/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
7/1/2009
6/29/2009
Legend
CIS 1,2DCERESULTS(Mg/l)
$- <70
^ 70 - 200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for CIS 1,2 DCE in groundwater is 70 ug/kg.
2. Qualifiers: Q
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
D - Concentration is reported from a dilution of the sample.
20 40
Z_
Feet
1 inch = 40 feet
80
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 4-5
BASELINE CIS-1,2-DICHLOROETHENE
RESULTS IN GROUNDWATER
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Well
Location
EW-S3
MPE-01
MPE-03
MPE-14
MPE-21
RW-01
RW-02
RW-05
RW-07
RW-07B
RW-08
RW-09
RW-10B
TW-31
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/9/2010
8/16/2010
8/16/2010
TCE RESULTS (\igl\)
•fy <5
^ 5-200
+ >200
O Not Sampled
ISTT Area A Boundary
Notes:
1. The site cleanup goal for TCE in groundwater is 5 ug/kg.
2. Qualifiers:
J - Quantisation is estimated as it is below the sample-specific
detection limit.
D - Concentration is reported from a dilution of the sample.
0 20 40
Z_
Feet
1 inch = 40 feet
80
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
ISTT OPERATIONS
TRICHLOROETHENE RESULTS
IN GROUNDWATER - AUGUST 2010
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
EW-S3
MPE-01
MPE-03
MPE-14
MPE-21
RW-01
RW-02
RW-05
RW-07
RW-07B
RW-08
RW-09
RW-10B
TW-31
6
40
10
10
32
5 U
5 U
250
14
5 U
5 U
5 U
5 U
1 J
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/16/2010
8/9/2010
8/16/2010
8/16/2010
Legend
CIS-1,2-DCE RESULTS (\igl\)
-^ <70
^ 70-200
+ >200
O Not Sampled
ISTT Area A Boundary
Notes:
1. The site cleanup goal for CIS 1,2 DCE in groundwater is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
0 20 40
80
_
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 6-2
ISTT OPERATIONS
CIS-1,2-DICHLOROETHENE
RESULTS IN GROUNDWATER - AUGUST 2010
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
62
^ATER
— -_
Well TCE Results Sample
Location (M9/I)
1
MPE-02
MPE-03
MPE-08
MPE-09
MPE-14
1
MPE-15
MPE-17
MPE-18
MPE-21
MPE-22
RW-01
RW-02
RW-03 1
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10B
TW-31
Date
5U 1/25/2011
5U 1/25/2011
20 1/25/2011
7 1/25/2011
5U 1/25/2011
26 1/25/2011
19 1/25/2011
5U 1/25/2011
4J 1/25/2011
8 1/25/2011
5U 1/25/2011
5U 1/25/2011
80 1/25/2011
3J 1/25/2011
15 1/25/2011
1 J 1/25/2011
1 J 1/25/2011
5U 1/25/2011
2J 1/25/2011
12 1/25/2011
5U 1/25/2011
1 J 1/25/2011
^— ^
—
Legend
TCE RESULTS (pg/l)
^ < 5
^ 5-200
^ >200
O Not Sampled
110 CENTER
STREET
_^X RW-70B
Jt=J4
MPE-09 -(j)- MPE-08/
V
^oa
-^M/
MPE-18 I r
„* * «
108
^ Of
ISTT Area A Boundary
Notes:
1. The site cleanup goal for TCE in groundwater is 5 u§/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 6-3
ISTT OPERATIONS
TRICHLOROETHENE RESULTS
IN GROUNDWATER - JANUARY 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
62
^ATER
— - —
Well CIS-1.2-DCE Sample
Location Results (|jg/l) Date
MPE-02
MPE-03
MPE-08
MPE-09
MPE-14
MPE-15
MPE-17
MPE-18
MPE-21
MPE-22
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10B
TW-31
5U 1/25/2011
1 J 1/25/2011
8 1/25/2011
2J 1/25/2011
5U 1/25/2011
8 1/25/2011
13 1/25/2011
5U 1/25/2011
3J 1/25/2011
2J 1/25/2011
5U 1/25/2011
5U 1/25/2011
88 1/25/2011
2J 1/25/2011
4J 1/25/2011
1 J 1/25/2011
5U 1/25/2011
5U 1/25/2011
5U 1/25/2011
1 J 1/25/2011
5U 1/25/2011
5U 1/25/2011
-,
Legend
CIS-1,2 DCE RESULTS
4- <70
-^ 70 - 200
4- >200
O Not Sampled
-^X RW-10B
Jt=J4
' MPE-09 -(j>- MPE-0 *
h
^W-05
^ Of
STREET
ISST Area A Boundary
Notes:
1. The site cleanup goal for CIS 1,2 DCE in groundwater is 70 U§/K§-
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sample-specific
detection limit.
0 20 40
Z
Feet
1 inch = 40 feet
80
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 6-4
ISTT OPERATIONS
CIS-1,2-DICHLOROETHENE RESULTS
IN GROUNDWATER - JANUARY 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JMH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Boring
Location
CSB-01
CSB-03
CSB-08
CSB-09
CSB-10
CSB-12
CSB-12
CSB-06
CSB-07
CSB-13
CSB-11
CSB-16
CSB-14
CSB-15
Sample
Date
4/5/2011
4/5/2011
4/6/2011
4/6/2011
4/6/2011
4/6/2011
4/6/2011
4/8/2011
4/7/2011
4/7/2011
4/12/2011
4/12/2011
4/11/2011
4/8/2011
FIGURE 7-3
TCE RESULTS
0-11 ft BGS
• <77
O 77 - 500
• >500
O 290 - 330 U
Multiple samples collected
within Figure depth range
Thermal Treatment Area
Notes:
1. The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the sampling-specific
detection limit.
0 20 40
it
Feet
1 inch = 40 feet
80
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION SOIL SAMPLING
TRICHLOROETHENE - 0-11 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
^^^™
Boring
Location
CSB-02
CSB-03
CSB-04
CSB-04
CSB-05
CSB-06
CSB-07
CSB-07
CSB-08
CSB-08
CSB-09
CSB-10
CSB-11
CSB-13
CSB-14
CSB-15
CSB-16
Start
Depth
14
19
11
15
13
10
io|
16
20
24
15
23
11
15
1l|
17
11
End
Depth
16
21
13
17
15
12
12J
18
22
26
17
25
13
17
ia|
19
13
TCE
(M9/kg)
6 U
400 U
310 U
255 U
220 U
6 U
6 U
5 U
400 U
250 U
330 U
5600
2 U
290 U
7 U
390 U
6 U
Sample
Date
4/4/201 1
4/5/201 1
4/12/2011
4/12/2011
4/11/2011
4/8/201 1
4/7/201 1
4/7/201 1
4/6/201 1
4/7/201 1
4/6/201 1
4/6/201 1
4/12/2011
4/7/201 1
4/11/2011
4/8/201 1
4/12/2011
Legend
TCE RESULTS
11-26ftbgs(Lig/kg)
O <77
O 77 - 500
• >500
O 220 - 400 U
Multiple samples collected
within Figure depth range.
Thermal Treatment Area
Notes:
1. The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit
0 20 40
80
Feet
1 inch = 40 feet
Nbbis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 7-4
CONFIRMATION SOIL SAMPLING
TRICHLOROETHENE - 11-26 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
Boring
Location
CSB-01
CSB-01
CSB-02
CSB-02
CSB-03
CSB-04
CSB-05
CSB-05
CSB-09
CSB-10
CSB-13
CSB-14
CSB-15
Start End TCE
Depth Depth (|jg/kg)
27
33
28
38
33
29
27
39
27
39
41
31
37
29
35
30
40
35
31
29
41
29
41
42
33
39
5 U
1 J
1 J
5 U
1 J
340 U
6 U
5 U
5 U
4 J
300 U
4 U
5 U
Sample
Date
4/5/201 1
4/5/201 1
4/4/201 1
4/4/201 1
4/5/201 1
4/12/2011
4/11/2011
4/12/2011
4/6/201 1
4/7/201 1
4/7/201 1
4/11/2011
4/8/201 1
Legend
TCE RESULTS
26-45 ft bgs
• <77
O 77 - 500
• >500
O 300 - 340 U
Multiple samples collected
within Figure depth range.
Thermal Treatment Area
Notes:
1 . The site cleanup goal for TCE in vadose zone soil is 77 ug/kg.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the
sample-specific detection limit.
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION SOIL SAMPLING
TRICHLOROETHENE - 26-45 FT BGS
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
110 CENTER
^ *^^>
RW-07B, .
^ RW-07
Well
Location
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
3/23/2011
3/21/2011
3/22/2011
3/21/2011
3/23/2011
3/22/2011
3/21/2011
3/23/2011
3/21/2011
3/22/2011
3/22/2011
3/22/2011
3/23/2011
3/23/2011
3/23/2011
3/23/2011
108 CENTER
RW-10B
TW-31
TW-40
TW-47
TCE RESULTS (Lig/l)
•fy <5
-$- 5-200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for TCE in groundwater is 5 ug/l.
2. Qualifiers:
U - Not detected above the sample-specific detection limit.
J - Quantisation is estimated as it is below the
sample-specific detection limit.
0 20 40
80
Feet
1 inch = 40 feet
Nbbis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 1
TRICHLOROETHENE RESULTS
MARCH 21-23, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
Well
Location
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
TW-40
TW-47
CIS-1,2-DCE
Results (|jg/L)
17
5 U
2 J
3 J
9[
19
5 U
13
5 U
1 J
9
5 U
5 U
5 J
5 U
5 U
Sample
Date
3/23/2011
3/21/2011
3/22/2011
3/21/2011
3/23/2011
3/22/2011
3/21/2011
3/23/2011
3/21/2011
3/22/2011
3/22/2011
3/22/2011
3/23/2011
3/23/2011
3/23/2011
3/23/2011
•
Legend
CIS 1,2 DCE RESULTS
4- <70
-^ 70-200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for CIS 1,2 DCE in groundwater is 70 ug/l.
2. Qualifiers:
U - Not detected above the sample-specific detection limit
J - Quantisation is estimated as it is below the sample-specific
detection limit.
0 20 40
3E_
Feet
1 inch = 40 feet
80
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 1
CIS-1,2-DICHLOROETHENE RESULTS
MARCH 21-23, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
TCE Results
(M9/L)
15
5 U
5 U
Sample
Date
5/3/2011
5/3/2011
5/2/2011
5/4/2011
5/4/2011
5/3/2011
5/3/2011
5/4/2011
5/3/2011
5/4/2011
5/2/2011
5/3/2011
5/3/2011
5/2/2011
5/2/2011
5/3/2011
Well
Location
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
MPE-061
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
T\AMO
T\AM7
Legend
TCE RESULTS
fT\ j r-
^r^ — ^
-^ 5-200
+ >200
ISTT Area A Boundary
1. Well MPE-06 was used as a substitute for RW-07
during the Confirmation Groundwater Sampling Event No. 2 only.
2. The site cleanup goal for TCE in groundwater is 5 ug/l.
3. Qualifiers:
U - Not detected above the sample-specific detection limit
J - Quantisation is estimated as it is below the sample-specific
detection limit
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 7-8
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 2
TRICHLOROETHENE RESULTS
MAY 2-4, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: August 2011
-------
Well CIS-1.2-DCE
Location Results (|jg/L)
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
MPE-06
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
TW-40
TW-47
5/3/2011
5/3/2011
5/2/2011
5/4/2011
5/4/2011
5/3/2011
5/3/2011
5/4/2011
5/3/2011
5/4/2011
5/2/2011
5/3/2011
5/3/2011
5/2/2011
5/2/2011
5/3/2011
FIGURE 7-9
CIS 1,2DCE RESULTS
+ <70
-^ 70-200
+ >200
ISTT Area A Boundary
Well MPE-06 was used as a substitute for RW-07
during the second confirmation sampling event only.
2. The site cleanup goal for CIS 1,2 DCE in groundwater is 70 ug/l.
3. Qualifiers:
U - Not detected above the sample-specific detection limit
J - Quantisation is estimated as it is below the sample-specific
detection limit
0 20 40
80
_
Feet
1 inch = 40 feet
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 2
CIS-1,2-DICHLOROETHENE RESULTS
MAY 2-4, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Well
Location
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
TW-40
TW-47
TCE Results
(M9/L)
38
5 U
5 U
Sample
Date
8/3/2011
8/3/2011
8/2/2011
8/3/2011
8/3/2011
8/2/2011
8/2/2011
8/1/2011
8/1/2011
8/2/2011
8/2/2011
8/1/2011
8/1/2011
8/4/2011
8/2/2011
8/4/2011
FIGURE 7-10
TCE RESULTS (Mg/l)
+ <5
-^ 5-200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for TCE in groundwater is 5 ug/l.
2. Qualifiers:
U - Not detected above the sample-specific detection limit
J - Quantisation is estimated as it is below the sample-specific
detection limit
0 20 40
80
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 3
TRICHLOROETHENE RESULTS
AUGUST 1 -4, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
-------
Well
Location
EW-S3
RW-01
RW-02
RW-03
RW-04
RW-05
RW-06
RW-07
RW-07B
RW-08
RW-09
RW-10
RW-10B
TW-31
1\N-40
TW^7
CIS-1,2-DCE
Results (|jg/L)
17
5 U
5 U
11
14
78
5 J
9
5 U
5 U
5 U
2 J
5 U
4 J
5 U
5 U
Sample
Date
8/3/201 1
8/3/201 1
8/2/201 1
8/3/201 1
8/3/201 1
8/2/201 1
8/2/201 1
8/1/2011
8/1/2011
8/2/201 1
8/2/201 1
8/1/2011
8/1/2011
8/4/201 1
8/2/201 1
8/4/201 1
— _
Legend
CIS 1,2DCE RESULTS
+ <70
-^ 70-200
+ >200
ISTT Area A Boundary
Notes:
1. The site cleanup goal for CIS 1,2 DCE in groundwater is 70 ug/l.
2. Qualifiers:
U - Not detected above the sample-specific detection limit
J - Quantisation is estimated as it is below the sample-specific
detection limit
0 20 40
80
_
Feet
1 inch = 40 feet
Nobis
Engineering a Sustainable Future
Nobis Engineering, Inc.
585 Middlesex Street
Lowell, MA 01851
(978) 683-0891
www.nobisengineering.com
FIGURE 7-11
CONFIRMATION GROUNDWATER SAMPLING EVENT NO. 3
CIS-1,2-DICHLOROETHENE RESULTS
AUGUST 1 -4, 2011
GROVELAND WELLS SUPERFUND SITE
GROVELAND, MASSACHUSETTS
PREPARED BY: JH
PROJECT NO. 80037
CHECKED BY: DB
DATE: September 2011
------- |