EPA 542-R-14-003
April 2014
T1. . p. . Office of Solid Waste and www.epa.gov/superfund/remedytech
United States ^ /^-,m i /**
Environmental Protection Emergency Response (5203P) www.clu-m.org/optimization
Agency
Remedial Design-Stage Optimization
Review Report
Sandy Beach Ground Water Plume Superfund Site
Tarrant County, Texas
EPA Region 6
Prepared for United States
Environmental Protection Agency
Prepared by Tetra Tech, Inc. and GSI Environmental, Inc.
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EXECUTIVE SUMMARY
Optimization Background
U.S. Environmental Protection Agency defines optimization as the following:
"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 some other approaches to identify opportunities for greater efficiency and effectiveness.
Contractors, states, tribes, the public, andPRPs are also encouraged to put forth opportunities for
the Agency to consider. "'
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 EPA
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).
1 U.S. Environmental Protection Agency. 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.
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Site-Specific Background
The Sandy Beach Road Ground Water Plume Superfund Site, CERCLIS ID No. TXN000605649, is
located within incorporated areas of Pelican Bay and Azle, Texas and an unincorporated portion of
Tarrant County, Texas. The site is the location of a former unpermitted landfill where existing ravines
were used to deposit waste and later backfilled. Releases of trichloroethene (TCE) from the landfill
migrated through shallow soil to the underlying Paluxy Aquifer, which is a local source of drinking water.
The former landfill has since been converted to residential property with significant open space. The
source area is currently owned by an innocent owner operator (IOO). The basis for taking action at the
site is the exceedance of drinking water standards in private water wells and in Pelican Bay public water
supply (PWS) wells screened in the Paluxy Aquifer.
In 2004, the Texas Commission on Environmental Quality (TCEQ) reported that PWS wells in Pelican
Bay, as well as private residential wells, were contaminated by TCE at concentrations exceeding the
Maximum Contaminant Level (MCL). TCEQ subsequently investigated area groundwater, with support
from EPA. The affected PWS wells were shut down and filtration units were installed on the affected
private water wells. The site was added to the National Priorities List (NPL) in 2005 and a remedial
investigation (RI) and feasibility study (FS) were finalized in 2011. The Record of Decision (ROD) was
published in 2011. Water supply connections from the City of Azle distribution system have replaced all
of the filtration systems, except for the residences located along Liberty School Road and one residence
located on Sandy Beach Road, to address exposure pathways associated with contaminated water
supplies. In addition to providing clean water for residents, remedies proposed for the site include soil
vapor extraction (SVE), in situ bioremediation (ISB) and groundwater extraction and treatment (pump
and treat; or P&T) remedy components. The site is currently in the remedial design phase.
The optimization review team along with the site project managers and regional consultants conducted a
site visit in April 2013. This site optimization review report includes recommendations based on review
of site documents, finding of the site visit and meeting with EPA remedial project managers (RPM).
Summary of Conceptual Site Model and Key Findings
In site decision documents, the most likely source of contamination to soil and groundwater was
identified as an unpermitted landfill that operated from 1958 to 1971 north of Sandy Beach Road and east
of Mountain View Road. Source identification was accomplished through review of historic aerial photos
and site investigations including a passive soil gas survey and geophysical surveys. Historic records on
the type and quantity of material buried at the site are unavailable. Minimally invasive source
characterization was performed to comply with the wishes of the current IOO.
The optimization review team has identified uncertainties about materials remaining in the source as a
data gap in the CSM. The primary release mechanisms at the landfill is believed to be historic direct
disposal of TCE into the ravines (RI, June 2011), however, the potential presence of intact drums of
chlorinated solvents or other primary sources may be important to the design of the remedial response.
The secondary sources of contamination include affected soils beneath and around the ravines, where
TCE may volatilize or leach to groundwater. Shallow soils consist of a mixture of silty to sand clays,
clayey sands and silty sand. Saturation occurs at a depth below 70-75 feet below ground surface (ft bgs)
in the source area. The precise distribution of TCE in shallow and saturated soils, including its
distribution in soils of varying porosity (for example clays versus sands), is another data gap affecting the
design of the source remedies.
The Paluxy Aquifer is a shallow water table aquifer underlying the former landfill. The Paluxy Aquifer
generally has no more than 25 ft of saturated thickness, eventually discharging to Walnut Creek
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approximately 1A mile downgradient. The Twin Mountains Aquifer is located at a depth over 400 ft bgs
and is separated from the Paluxy Aquifer by the Glen Rose Formation. Unsaturated soil between the Glen
Rose Formation and the Twin Mountains Aquifer indicates that the Paluxy Aquifer is perched on top of
the Glen Rose Formation. Many private and some PWS wells have drawn or continue to draw water from
the affected depths of the Paluxy Aquifer. The Twin Mountains Aquifer is an active source of drinking
water. Groundwater analytical results also indicate that the Twin Mountains Aquifer has been impacted
by TCE in one location through a private well (GW-39) that screens both aquifers; contamination in the
impacted Paluxy Aquifer appears to migrated to the Twin Mountains Aquifer in the area of this well.
Additional data gaps relevant to the proposed remedies include questions surrounding the potential water
quality impact from ISB treatments and the effect of back- or matrix-diffusion from low permeability
deposits on the magnitude and persistence of the dissolved phase plume.
Summary of Recommendations
Recommendations are provided to improve remedy design in the areas of effectiveness and cost
efficiency. The majority of recommendations address data gaps in the CSM. The recommendations in
these areas are as follows:
Improving effectiveness -
Recommendations to improve the effectiveness of the proposed remedy include prioritizing and
sequencing remedial activities. The optimization review team recommends plugging, abandoning and if
necessary, replacing the remaining impacted private water supply wells that may provide human exposure
and migration pathways to lower units.
Installation of the SVE in the source area should be prioritized both as a means of direct source treatment
and control and to address data gaps. The potential for additional sources of TCE (such as buried drums)
can be evaluated during the installation of the SVE system. Typically, extraction wells would be installed
before trenching and piping, but in this case, the optimization review team suggests implementing
trenching and piping in this area first, during which the site team can observe the nature of the debris to
evaluate evidence of residual drums, tanks or other vessels that may contain TCE. If there is evidence of
additional sources, then the site team should proceed with planning for excavation of these potential
sources. The source remedy design process should be flexible and adaptive, in order to incorporate data
gathered during installation of the SVE to optimize placement of remedial components.
The optimization review team recommends characterization of the source area saturated soils during
installation of the SVE wells. The deeper interval SVE wells should be installed through the deep
unsaturated zone and soil samples from various intervals in the saturated zone collected (using sonic
drilling techniques) and analyzed for contaminants. Characterization data should be used to identify areas
of contamination that may provide long-term sources of contaminants to groundwater.
To optimize the efficacy of ISB treatment and identify potential water quality impacts, the optimization
review team recommends performing an additional site ISB pilot test.
After source treatment, plume migration control is the next highest priority. The hydraulic control system
as presented in the Preliminary Design Report (EA 2013) should include a minimum number of wells to
provide hydraulic control of the plume. The optimization review team also recommends appropriate
scaling of the groundwater P&T system by reducing the initial number of extraction wells. However, the
optimization review team recommends increasing the capacity of the groundwater treatment plant up to
150 gallons per minute (gpm), as a contingency in case the extraction system needs to be expanded. If
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full-scale P&T were required due to plume migration, the scaled-up treatment plant would be available to
accommodate the increased treatment volumes. This report also provides recommendations to simplify
the design of the treatment plant to include a liquid granular activated carbon (LGAC) treatment process.
This optimization review report also recommends a groundwater performance monitoring plan to confirm
control of the plume and the performance of aggressive source remediation.
Reducing cost -
Recommendations to prioritize source area remediation and combine additional source area
characterization with implementation of the currently planned SVE system are anticipated to reduce costs
over the lifetime of the project. Additional costs associated with sampling in the source area are estimated
at $100,000; however costs are anticipated to be offset by more efficient remedy design, contaminant
mass removal and a shorter operation life time for the SVE remedy.
Recommendations for appropriate scaling and streamlining of the P&T system are also anticipated to
reduce life-cycle costs. Remedy performance monitoring along with establishing remedy operation exit
(or termination) criteria for each remedy component can help reduce the risk of operating a remedy past
the point of effectiveness.
Technical improvement -
Technical improvements for the proposed remedy are anticipated to result from additional site
characterization (to refine remedy component placement), pilot testing of ISB treatment and remedy
performance monitoring accompanied by continued good data management practices. Prioritizing the
source remedy is anticipated to provide the maximum reduction in residual contaminant mass, improving
the long-term efficacy of the hydraulic control system. Recommendations on the scale and design of the
P&T system should improve the efficacy of plume hydraulic control.
Site closure -
Recommendations that are anticipated to shorten the time to attain cleanup goals include additional source
area characterization during installation of the SVE system, pilot testing the ISB amendments, prioritizing
source area cleanup and implementing remedy performance monitoring.
Green remediation -
No specific recommendations have been provided for environmental footprint reduction. However,
several of the above recommendations have the potential to reduce the remedy footprint by either
streamlining the treatment process or reducing the likelihood of operating a remedy component past the
point of measureable benefit in achieving the associated remedial action objective(s).
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NOTICE AND DISCLAIMER
Work described herein was performed by Tetra Tech for the U.S. Environmental Protection Agency. GSI
Environmental performed work under a subcontract to Tetra Tech. Work conducted by Tetra Tech,
including preparation of this report, was performed under Work Assignment 2-58 of EPA contract EP-W-
07-078 with Tetra Tech Inc., Chicago, Illinois. The report was approved for release as an EPA document,
following the Agency's administrative and expert review process
This optimization review is an independent study funded by the EPA that focuses on protectiveness, cost-
effectiveness, site closure, technical improvements and green remediation. Detailed consideration of EPA
policy was not part of the scope of work for this review. This report does not impose legally binding
requirements, confer legal rights, impose legal obligations, implement any statutory or regulatory
provisions or change or substitute for any statutory or regulatory provisions. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use.
Recommendations are based on an independent evaluation of existing site information, represent the
technical views of the optimization review team and are intended to help the site team identify
opportunities for improvements in the current site remediation strategy. These recommendations do not
constitute requirements for future action; rather, they are provided for consideration by the EPA Region
and other site stakeholders.
While certain recommendations may provide specific details to consider during implementation, these
recommendations are not meant to supersede other, more comprehensive, planning documents such as
work plans, sampling plans and quality assurance project plans (QAPP); nor are they intended to override
applicable or relevant and appropriate requirements (ARARs). Further analysis of recommendations,
including review of EPA policy may be needed prior to implementation.
Sandy Beach Road Ground Water Plume Superfimd Site Remedial Design-Stage Optimization Review Report
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PREFACE
This report was prepared as part of a national strategy to expand Superfund optimization practices from
site assessment to site completion implemented by the United States Environmental Protection Agency
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)
Kirby Biggs
J OO
EPA OSRTI
Technology Innovation and Field
Services Division (TIFSD)
2777 Crystal Drive
Arlington, VA 22202
biggs.kirby(g),epa.gov
phone: 703-823-3081
Tetra Tech
(Contractor to EPA)
Jody Edwards, P.O.
Peter Rich, P.E.
Tetra Tech, Inc.
1881 Campus Commons Drive, Suite 200
Reston,VA 20191
jody.edwardsigitetratech.com
phone: 802-288-9485
Tetra Tech, Inc.
51 Franklin Suite, Suite 400
Annapolis, MD 21401
peter.rich@tetratech.com
phone: 410 990-4607
GSI Environmental
(Contractor to Tetra Tech)
Mindy Vanderford, Ph.D.
GSI Environmental, Inc.
2211 Norfolk, Suite 1000
Houston, TX 77098
mvanderford(g),gsi-net.com
phone: 713-522-6300x186
The national optimization strategy includes a system for tracking consideration and implementation of the
optimization 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.2
2 U.S. Environmental Protection Agency. 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.
Sandy Beach Road Ground Water Plume Superfund Site
Tarrant County, Texas
Remedial Design-Stage Optimization Review Report
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LIST OF ACRONYMS
ARAR Applicable or Relevant and Appropriate Requirement
bgs Below ground surface
CERCLA Comprehensive Environmental Restoration Compensation and Liability Act
CSM Conceptual site model
COC Contaminant of concern
Cis-1,2 DCE c/'s-l,2-Dichloroethene
DPT Direct-push technology
EA EA Engineering, Science and Technology, Inc.
EPA U.S. Environmental Protection Agency
ERT Environmental Response Team
EW Extraction well
FS Feasibility study
ft feet
GAC Granular activated carbon
gpm gallons per minute
GW Groundwater
FฃASP health and safety plan
HQ Headquarters
1C Institutional control
ISB In situ bioremediation
IOO Innocent owner operator
IW Injection well
LGAC Liquid phase granular activated carbon
MCL Maximum Contaminant Level
MW Monitoring well
NPL National Priorities List
O&F Operational and Functional
O&M Operation and Maintenance
ORP Oxidation reduction potential
OSRTI Office of Superfund Remediation and Technology Innovation
PCL Protective concentration levels
P&T Pump and treat
PWS Public water supply
QAPP Quality assurance project plan
RA Remedial Action
RAC Remedial action contractor
RAO Remedial action objective
RD Remedial design
RI Remedial investigation
ROD Record of Decision
RPM Remedial Project Manager
SAP Sampling and analysis plan
SVE Soil vapor extraction
TCE Trichloroethene
TCEQ Texas Commission on Environmental Quality
TIFSD Technology Innovation and Field Services Division
TOC Total organic carbon
Sandy Beach Road Ground Water Plume Superfund Site
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TRRP Texas Risk Reduction Program
(ig/L micrograms per liter
VC Vinyl chloride
VOC Volatile organic compound
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TABLE OF CONTENTS
Section Page
1.0 OBJECTIVES OF OPTIMIZATION REVIEW 1
2.0 OPTIMIZATION REVIEW TEAM 2
2.1 Quality Assurance 2
3.0 REMEDIAL ACTION OBJECTIVES AND PROPOSED REMEDIES 3
3.1 Remedial Action Objectives and Affected Media 3
3.2 Proposed Remedies 6
3.3 Current Exit Strategy 7
4.0 FINDINGS 8
4.1 Data Gaps and Characterization 8
4.2 Remedial Strategy 8
5.0 RECOMMENDATIONS 9
5.1 Recommendations to Eliminate Exposure Pathway and Vertical Migration by
Replacing Specific Private Water Supply Wells 9
5.2 Recommendations for Source Characterization and Treatment 9
5.3 Recommendations for Phased P&T for Plume Migration Control and Aquifer
Restoration, If Needed 11
5.4 Recommendations for Streamlined Groundwater Treatment Plant 12
5.5 Recommendations for Remedy Performance Monitoring 13
5.6 Recommendations for Data Management 15
5.7 Recommendations for Establishing Remedy Operation Exit Criteria 15
5.8 Recommendations for Environmental Footprint Reduction 17
Sandy Beach Road Ground Water Plume Superfimd Site Remedial Design-Stage Optimization Review Report
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TABLES
Table Page
1 Optimization Review Team 2
2 Other Optimization Review Contributors 2
3 Contaminants of Concern and Cleanup Goals 5
4 Affected or Potentially Affected Media on Site 5
5 Remedial Action Objectives as Stated in the Record of Decision 5
6 Remedies Documented in the Record of Decision and Preliminary Design Report 6
7 Identified Data Gaps 8
8 Recommendation Summary 18
FIGURES
1 Site location 1
2 Location of source area 3
3 Distribution of TCE contamination in the Paluxy aquifer 3
4 Geologic cross-section 4
APPENDICES
A References
B Supporting Figures from Existing Documents
C Remedy Performance Monitoring Recommendations
D Monitoring and Remediation Optimization System Analysis Reports
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1.0 OBJECTIVES OF OPTIMIZATION REVIEW
For more than a decade, the Office of Superfund Remediation and Technology Innovation (OSRTI) has
provided technical support to the EPA regional offices through the use of independent (third party)
optimization reviews at Superfund sites. The Sandy Beach Road Ground Water Plume Superfund Site
(Sandy Beach Site) was nominated for an optimization review at the request of the Region 6 remedial
project manager (RPM) in January 2013. The current optimization review of the site is intended to
improve protectiveness, reduce cost and reduce the time required to attain cleanup goals.
The site is located within incorporated areas of
Pelican Bay and Azle, Texas and an unincorporated
portion of Tarrant County, Texas in EPA Region 6
(Figure 1). The site was added to the National
Priorities List (NPL) on September 14, 2005, and
activities under CERCLA have been on-going since
this time. Site Remedial Investigation (RI) (EA
2010a) and Feasibility Study (FS) (EA 201 Ob)
reports were finalized in June and September 2011,
respectively, and a Record of Decision (ROD) (EPA
2011) was signed in September 2011. The site is
currently in the Remedial Design (RD) phase.
To this end, an optimization review team (described
below) was assembled and met with regulatory
stakeholders and consultants in Dallas, Texas and at
the site to review site data, remediation goals,
potential funding and time frames to implement the
remedy. The optimization team also reviewed site
documents. This report summarizes the findings and
recommendations of the optimization review team.
Objectives of this RD-stage optimization review
include:
Figure 1: Site location.
N
Topographk: Map Source:
Adapted from Azle Quadrangle. Tx . 7.5 minute
USGS quadrangle map. 1&55, photoinspected 1S78
1MO 2030 Feซ
Excerpt from Figure 1 of the September 2011 ROD. A full size version
of this figure is provided in Appendix B.
Review of conceptual site model (CSM)
Review of Remedial Action Objectives (RAO)
Review of proposed remedies and associated costs
Provide recommendations for:
o CSM improvements
o Remedy improvements
o Prioritization and sequencing of the remedy components
o Performance monitoring metrics in support of exit criteria for each remedy component
Green remediation is not a primary objective for this optimization review and specific recommendations
for green remediation are not provided. However, several of the remedy optimization recommendations
have the potential to reduce the remedy footprint by either streamlining the treatment process or reducing
the likelihood of operating a remedy component past the point of measureable benefit in achieving the
associated RAO(s).
Sandy Beach Road Ground Water Plume Superfund Site
Tarrant County, Texas
Remedial Design-Stage Optimization Review Report
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2.0 OPTIMIZATION REVIEW TEAM
The remedy design-stage optimization review team consisted of the independent, third-party participants
listed in Table 1. The optimization review team collaborated with representatives of EPA Headquarters
(HQ) (OSRTI and Environmental Response Team [ERT]) and EPA Region 6, the Texas Commission on
Environmental Quality (TCEQ) and representatives of EA Engineering, Science and Technology, Inc.
(EA), the Remedial Action Contractor (RAC) for EPA Region 6.
The independent, third-party optimization review team consisted of the following individuals:
Table 1: Optimization Review Team
Name
Kirby Biggs
Tom Kady
Doug Sutton
Mindy Vanderford
Organization
EPA HQ OSRTI
EPA HQ ERT
Tetra Tech
GSI Environmental, Inc.
Phone
703-299-3438
732-735-5822
732-409-0344
713-522-6300
Email
biggs.kirby@epa.gov
kady.thomas@epa.gov
doug . sutton@tetratech . com
mvanderford@gsi-net.com
The individuals listed in Table 2 also contributed to the optimization review process:
Table 2: Other Optimization Review Contributors
Name
Vincent Malott
Marilyn Czimer Long
Buddy Henderson
Jay Snyder
Stan Wallace
Organization
EPA Region 6
TCEQ
TCEQ
EA
EA
Title/Party
RPM and Region 6
Optimization Liaison
Project Manager
Project Technical Support
RAC Consultant
RAC Consultant
Present for Site
Visit/Site Meeting
Yes
Yes
Yes
Yes
Yes
A site visit followed by a meeting at Region 6 HQ in Dallas, Texas occurred on April 24, 2013.
Documents reviewed during the optimization review process are listed in Appendix A.
2.1 Quality Assurance
This optimization review used existing environmental data to interpret the CSM, evaluate potential future
remedy performance and make recommendations to improve the remedy. The quality of the existing data
was evaluated by the optimization review team before use. The evaluation for data quality included a
brief review of how the data were collected and managed (where practical, the site QAPP was
considered), the consistency of the data with other site data and the use of the data in the optimization
review. Data that were of suspect quality were either not used as part of the optimization review or were
used with the quality concerns noted. Where appropriate, this report provides recommendations to
improve data quality.
Sandy Beach Road Ground Water Plume Superfimd Site
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3.0 REMEDIAL ACTION OBJECTIVES AND PROPOSED REMEDIES
The Sandy Beach site is the location of a former unpermitted landfill. Releases of trichloroethene (TCE)
from the landfill migrated to the shallow Paluxy aquifer, which is a local source of drinking water. The
current CSM is detailed in documents including the ROD (EPA 2011), RI (EA 2010a), FS (EA 201 Ob),
data evaluation summaries and the Preliminary Remedial Design Report (EA 2013) listed in Appendix A.
A summary of the CSM components relevant to remedial design (RD) and remedial action (RA) is
provided below.
3.1 Remedial Action Objectives and Affected Media
RAOs for the site were developed to address contaminants of concern (COCs) associated with the release
of TCE from a former unpermitted landfill that operated from 1958 to 1971 (Figure 2). The former
landfill has since been converted to residential property with significant open space. The source area is
currently owned by an innocent owner operator (IOO). The basis for taking action at the site is the
exceedance of drinking water standards in private water wells and Pelican Bay water supply wells
screened in the Paluxy Aquifer (Figure 3).
Figure 2: Location of source area as indicated by
overlay of passive soil gas sampling and
geophysics. Contamination is co-located with
buried debris on former landfill site that is now a
residence owned by an IOO
Figure 3: Distribution of TCE contamination in the
Paluxy aquifer
Explanation
"
TCE mass from passive
TJTK soil gas survey (nanogran
Soil gas survey point 2.500-10.000
Temporary fcorir>gr*e[l
10.000 - 30.000
! 20.000-35.000
35.000-50.000
Atove 50,000
Explanation
Dgetjrjgai syrcal Tfrfja
WrY-Ot * Monitoring well
GmEL * Private well
Paear9s>12 A Public well
'-1 Temporary boring/well
Mw-}7 Sample Location
--? TCE below reporting I imrt
| | TCE above 5 yg/L
I | TCE above 50 yg/L
365 67 TCE concentration (pgA- >. Depth of sample {ft btoc)
Figure is an excerpt of Figure 13 from the September 2011 ROD.
A full size version of the figure is provided in Appendix B.
Figure is an excerpt of Figure 16 from the September 2011 ROD. A
full size version of the figure is provided in Appendix B.
Sandy Beach Road Ground Water Plume Superfund Site
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Figure 4: Geologic cross-section along primary groundwater flow direction showing Paluxy formation
perched above the low permeability Glen Rose formation, and the underlying Twin Mountains Aquifer
4 -
I
?\ ^ ,".ฃ*ซ
PALUXY FORMATION
SAMJ WITH FOSaiLS AND SHELL *SWQRAVEL, AftUND/WT
OYSTER S*LLS(GRYFHEASP), LGHT YELLOWISH BRttWI TO
HDWKHTALSCALEIN FEET
BROWN TO OLWE YELLOW. SDFT-O STIFF, VERY FINEGRANED
8ILTY OM4D TO QAM) TO (Wrt>3TONC. LIOHT ORAY TO PALI
YELLOW TO VERY PALE BROiVN. \CRY =1NE TO FINE G^AINiD.
U*rORM ORUH QEE. CENE1ALLV NOFl COHEBI\ฃ WITH AFf^a
THAT ARE CEMENTED
TWIN MOUNT/W3 FORMATION
Y RED04SH BROWN, VERY FINE SAMJ. LIOHT GREENISH
SlTSTCNEl CA1CAREOU88ILT8TONF. TOCALWREOUS MNDr SILTSTO*. LIMESTONE ANDMAB, LI8HT(BEEMSH
SHALE GRAY, SOME CmY, MASSIVE TO UMINATED SOF" TO /EKY STIF=, GRADES DOWNWARD IMTO
LM-STDNE. ^6N WTO 3HISLE AM) MAซ- WTH DiPTH LIGHT GWEfcNSH GRAY SOFT TO VERY 1ARD
Figure is an excerpt of Figure 5 from the September 2011 ROD. A full size version of the figure is provided in Appendix B.
Area aquifers include the Paluxy Aquifer and the Twin Mountains Aquifer (Figure 4). The Paluxy
Aquifer is a shallow water table aquifer that ranges from approximately 75 feet (ft) below ground surface
(bgs) near the former unpermitted landfill to approximately 4 ft bgs near Walnut Creek. The Paluxy
Aquifer generally has no more than 25 ft of saturated thickness. The Twin Mountains Aquifer is over 400
ft bgs and is separated from the Paluxy Aquifer by the Glen Rose Formation. Unsaturated soil between
the Glen Rose Formation and the Twin Mountains Aquifer indicate that the Paluxy Aquifer is perched on
top of the Glen Rose Formation. Many private and some municipal water supply wells draw water from
the affected depths of the Paluxy Aquifer. The Twin Mountains Aquifer is another source of drinking
water.
TCE has migrated to the Twin Mountains Aquifer in at least one location through a private well (GW-39),
that screens both aquifers. The impacted Pelican Bay water supply wells have been shut down. A water
supply line was installed in 2006 under a Removal Action to provide municipal water to all but four
residences with impacted wells. Filtration systems were installed and maintained on private water supply
wells. Filtration systems are still currently maintained on the remaining four residential supply wells.
Paluxy Aquifer groundwater continues to be used by residents for irrigation purposes. The TCE plume
continues to migrate with two primary lobes: (1) the western lobe discharges to Walnut Creek and (2) the
eastern lobe migrates past the location of the impacted Pelican Bay water supply wells.
Sandy Beach Road Ground Water Plume Superfund Site
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Table 3 shows Site COCs and cleanup goals based on federal Maximum Contaminant Levels (MCLs).
Table 4 summarizes affected and potentially affected media along with potential exposure/migration
pathways. Table 5 lists RAOs for the source area and downgradient groundwater.
Table 3: Contaminants of Concern and Cleanup Goals
Constituent Name
TCE
c/s-l,2-Dichlroethylene (cis-1,2 DCE)
Affected Media
Paluxy and Twin
Mountains Aquifers
Cleanup Goal
5^g/L
70 Mg/L
Notes: COC = Contaminant of Concern; TCE = trichloroethene; ug/L = micrograms per liter
Table 4: Affected or Potentially Affected Media on Site
Medium
Unsaturated soil
and buried debris
Paluxy Aquifer
Twin Mountains
aquifer
Indoor air
Location
Ground surface to Paluxy
Aquifer water table in
approximate 200 feet by
200 feet source area
25 feet or less of
saturated thickness
starting between 25 and
75 feet below ground
surface
400+ feet below ground
surface
Residences
Composition
Clay, sandy clay
and sand
Sandstone,
mudstone,
limestone and
sand
Sandstone
Potential Exposure / Migration
Pathways
Discharge to shallow
groundwater
Direct exposure by
excavation
Ingestion of water from
Pelican Bay supply wells
Ingestion of water from
private supply wells
Discharge to Twin
Mountains Aquifer through
improperly constructed wells
Discharge to Walnut Creek
Ingestion of water from
Pelican Bay supply wells
Ingestion of water from
Private water supply wells
No risk based on human health risk assessment
described in Record of Decision (EPA 201 1)
Table 5: Remedial Action Objectives as Stated in the Record of Decision
Remedial Action Objective
Exposure
Prevention
Plume Containment
Aquifer Restoration
Source Control
Prevent human exposure to COCs from water supply wells at concentrations
above MCLs or ARARs
Prevent or minimize further migration of COCs in groundwater at concentrations
exceeding the MCLs or ARARs
Restore the groundwater to its expected beneficial uses, wherever practicable, so
that concentrations of COCs are less than the applicable MCLs or ARARs
Prevent or minimize further migration of COCs in the vadose zone soils that
would cause concentrations of COCs in groundwater to exceed MCLs or ARARs
and mitigate potential vapor intrusion
Notes: COC = contaminant of concern; MCL = maximum contaminant level; ARAR = applicable and relevant or appropriate requirement
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3.2 Proposed Remedies
Table 6 lists the remedies in the order presented in the ROD (EPA 2011) or Preliminary Design Report
(EA2013).
The ROD considered in situ bioremediation (ISB) as a potential source area groundwater remedy, but ISB
was not included as a final recommendation in the ROD due to cost concerns. A preliminary ISB pilot test
was performed prior to completion of the ROD with results indicating that ISB could be used to treat
dissolved groundwater contamination. Accordingly, ISB was evaluated with equal consideration to other
remedies as part of the optimization review.
Table 6: Remedies Documented in the Record of Decision and Preliminary Design Report
Remedy
Target Medium
Description
Water supply well
replacement
Drinking water
Plug and abandon impacted private water supply wells
and install new Twin Mountains Aquifer wells for
residences that cannot be served by the municipal water
line.
This component would include plugging and
abandoning water supply well GW-39 (the well that
currently provides a connection between the Paluxy and
Twin Mountains Aquifers).
Pump and treat
system
Paluxy Aquifer
The Preliminary Design Report (EA 2013) describes
treatment with filtration, air stripping with potential off-
gas treatment and effluent polishing with liquid phase
granular activated carbon. Two potential extraction
schemes are provided to contain the TCE plume:
1. Vertical extraction wells
23 extraction wells
109 gpm extraction rate
8 injection wells
2. Horizontal extraction wells
21 horizontal wells
1 vertical well
139 gpm extraction rate
8 injection wells
Soil vapor extraction
Source area soil
Extract contaminated soil vapors with horizontal or
vertical wells and treat off-gas with GAC. Includes
contingency to excavate and remove principal threat
waste from the source area if discovered during the
Remedial Design/Remedial Action data collection and
construction activities.
Institutional controls
Residential
properties and area
groundwater
Restrictive covenants, deed notices and/or other area-
wide restrictions of groundwater use.
Five-Year Reviews
All site media
Reports to document remedy performance and
protect veness.
Notes: GAC = granular activated carbon; gpm = gallons per minute; RD/RA= remedial design/remedial action; TCE = trichloroethene
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3.3 Current Exit Strategy
The ROD (EPA 2011) sets forth short-term expectations that the exposure to contaminated groundwater
will be prevented, that plume migration will be controlled and that source area soil will be remediated
(including excavation and removal of any principal threat wastes). The ROD (EPA 2011) also sets the
long-term expectation that the groundwater remedy will require approximately 30 years to restore the
aquifers. This Fund-lead remedy would be transferred to the State in 10 years after the remedy becomes
Operational and Functional (O&F).
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4.0 FINDINGS
This section presents key findings based on discussions during the optimization review meeting and
document review.
4.1 Data Gaps and Characterization
Several key data gaps and uncertainties in the CSM were identified for the site. Table 7 identifies data
gaps that may influence remedy design.
Table 7: Identified Data Gaps
Medium
Source material
Source area
saturated soils
Groundwater
Groundwater
Data Gap
Potential for additional
sources of TCE (such as
drums) in the buried debris
Unknown distribution and
mass of TCE in source area
saturated soils
Extent and duration of
water quality impacts from
potential in situ
bioremediation remedy
Impacts of matrix diffusion
on time frame for aquifer
restoration
Potential Recommendation
Evaluate presence of drums during SVE installation.
See recommendations in Section 5.1.
Characterize source area saturated soils to determine
if source area remediation is required for saturated
soils. See recommendations in Section 5.2.
Consider potential water quality effects and
mitigation approaches if bioremediation is used for
source area saturated soil remediation. See
recommendations in Section 5.2.
Monitor groundwater concentrations following
comprehensive source area remediation to determine
effect on morphology and migration of downgradient
plume. See recommendations in Section 5.3, 5.4, 5.5
and 5. 7.
Notes: SVE = soil vapor extraction; TCE = trichloroethene
4.2 Remedial Strategy
The optimization review team and site team agreed on a revised strategy for the site that prioritizes
activities as follows:
Eliminate exposure/migration pathways by plugging, abandoning and replacing specific wells.
Remediate the source area with SVE and potentially ISB, and further characterize and remove
principal threat wastes identified during the SVE installation.
Control plume migration through the installation of a streamlined P&T system.
Restore the aquifers through a combination of source remediation, plume migration control and
natural attenuation.
Expand the P&T system for dissolved plume remediation and aquifer restoration only if multiple
years of monitoring (5-year cycles suggested) suggest P&T is needed and capable of restoring the
aquifer in a timely and cost-effective manner.
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5.0 RECOMMENDATIONS
The recommendations provided by the optimization review team address the data gaps identified in
Section 4.1 and are consistent with the remedial strategy outlined in Section 4.2. The presentation of the
recommendations is consistent with the prioritization and sequencing presented in Section 4.2. Additional
recommendations are provided for performance monitoring, data management and development of exit
criteria for each remedy component.
Relative to the ROD (EPA 2011), the recommended strategy raises the priority of source remediation and
emphasizes performance monitoring and timely shutdown of remedy components. Collectively, the
recommendations help address key data gaps and satisfy the RAOs in a cost-efficient manner.
5.1 Recommendations to Eliminate Exposure Pathway and Vertical Migration by Replacing
Specific Private Water Supply Wells
Currently, private water supply wells GW-9, GW-10 and GW-
11 are supplying residents that are not being served by
municipal water. These wells continue to have filtration systems
that are operated by the State. In addition, the site team has
identified private water supply well GW-39 as having a
hydraulic connection between the contaminated Paluxy Aquifer
and the Twin Mountains Aquifer. Well GW-39 is no longer
used for potable purposes but is used for irrigation by the
homeowner; it has not been plugged and abandoned. This
connection is likely the primary preferential pathway for site-
related contamination to reach the Twin Mountains Aquifer, and
TCE has been observed in the Twin Mountains Aquifer
monitoring well downgradient of GW-39.
Recommendation 5.1.1: Plug, Abandon and Replace Water Supply Wells GW-9, GW-10, GW-11 and
GW-39
Benefits of Implementing Section
5.1 Recommendations
Eliminate exposure pathway over
the long term for three residences
not connected to public water
supply.
Prevent vertical migration of
contamination to the Twin
Mountains Aquifer.
The optimization review team supports prioritizing option DW-3 from the ROD; plug, abandon and
replace private water supply wells GW-9, GW-10, and GW-1 Ito eliminate exposure and GW-39 to
prevent plume migration. This remedial response will directly address the RAO to prevent human
exposure to COCs above MCLs and prevent or minimize further migration of COCs to the Twin
Mountains Aquifer. Based on discussions during the optimization review, the optimization review team
estimates that plugging, abandoning and replacing these wells (with Twin Mountain Aquifer wells or
public water supply) would cost approximately $600,000.
5.2
Recommendations for Source Characterization and Treatment
The source area includes contaminated unsaturated soils, and based on the results from the
characterization recommended in Section 4.1, may include contaminated saturated soils. There is also the
potential that as yet unidentified, but suspected, primary sources (such as buried drums) remain in the
source area. Property access restrictions in the area of the former unpermitted landfill require that source
investigations be minimally intrusive.
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Recommendation 5.2.1: Evaluate Potential Additional Sources During SVE System Installation
Benefits of Implementing Section
5.2 Recommendations
Identify if additional sources
are present.
Determine need for remediation
of source area saturated soils
while installing remedy for
unsaturated zone.
Reduce time to closure by
raising priority of source area
remediation.
Provide a means for source area
saturated zone remediation
without affecting water quality
for nearby residences using
groundwater.
Installation of the SVE in the source area should be prioritized
(after recommendations in 5.1.1) to (1) provide direct source
treatment and control and (2) address data gaps. Current access
restrictions prevent intrusive investigation for additional
sources; however, the potential for additional sources of TCE
(such as buried drums) can be evaluated during the installation
of the SVE system. The debris where additional sources may be
present is also the optimal location for several of the SVE wells.
Therefore, drilling and trenching (for extraction piping) will be
required in the debris. Typically, extraction wells would be
installed before trenching and piping, but in this particular case,
the optimization review team suggests that the trenching and
piping in this area occur first. During trenching and piping, the
site team can observe the nature of the debris for evidence of
residual drums, tanks or other vessels that may contain TCE.
Potential worker health and safety risks and risks to machinery
associated with buried debris should be included in the project-
specific health and safety plan.
If there is no evidence of such potential sources, the site team can proceed with drilling the extraction
wells in this area. The drill cuttings can be evaluated to determine the likelihood of an additional source
and/or long-term matrix diffusion from contaminated fine-grained material. Evaluation of source area
soils should include an estimate of residual contaminant mass to assess long-term source strength and
performance of the SVE remedy. If there is evidence of extensive residual or remaining sources, then the
site team should plan for excavation of these potential sources.
Recommendation 5.2.2: Characterize Source Area Saturated Soils
The optimization review team recommends characterization of the source area saturated soils. The site
team states that direct-push technology (DPT) is not an appropriate drilling technique for the Paluxy
Aquifer. Therefore, the optimization review team recommends characterization of the source area
saturated soils during installation of the SVE wells. The deeper interval SVE wells should be installed
through the deep unsaturated zone and soil samples from various intervals in the saturated zone collected
and analyzed for volatile organic compounds (VOCs). Groundwater should also be sampled from these
wells and analyzed for VOCs.
Air rotary drilling, which the site team has historically used at this site will not be appropriate for the soil
VOC investigation. Sonic drilling would be more appropriate for collecting these soil samples and
installing the wells. Sonic drilling would also provide useful soil cores for interpreting the Paluxy Aquifer
stratigraphy. If the site team has concerns about the use of sonic drilling, then the wells can be installed
with air rotary drilling with no soil sampling and analysis. The investigation would then be limited to
groundwater sampling and analysis.
Additional costs above the currently scoped installation of SVE wells, including mobilization of rigs for
sonic drilling and soil and groundwater sampling are anticipated to be in the range of $50,000. The cost
will include modification of sampling and analysis plan (SAP), the health and safety plan (HASP), and
interpretation of sampling results through the creation of detailed cross-sections and maps.
Recommendation 5.2.3: Prioritize Source Area Treatment Above Plume Containment and Aquifer
Restoration
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The optimization review team assigns a high priority to source area characterization and treatment,
because aquifer restoration cannot begin until the source is removed or controlled. The optimization
review team supports the SVE remedy for unsaturated soil and recommends that vertical wells be used for
remediation. Unless otherwise informed by findings during drilling of the SVE wells, shallow SVE wells
should be installed to extract vapors from 5 ft bgs to 15 ft bgs and deeper SVE wells should be installed to
extract vapors from 15 ft bgs to the water table (approximately 75 ft bgs). As described above, the screen
intervals of the deeper wells should be installed to fully screen the Paluxy Aquifer to provide a means of
sampling or injecting reagents into it. The horizontal arrangement of vertical SVE wells and associated
piping depicted in the Preliminary Design Report (EA 2013) is appropriate. One row of the SVE wells
should be installed through the center of the suspected debris field at the center of the source area as
defined by the existing passive soil gas sampling results and the proposed confirmation of no buried
drums in the debris.
Recommendations to combine source area characterization with the currently planned SVE system do not
impose significant additional costs.
Recommendation 5.2.4: Conduct Additional ISB Pilot Test to Evaluate Effectiveness as a Source Area
Remedy and Secondary Impacts to Water Quality
The ISB pilot test conducted by the site team was discontinued too early to determine (1) the extent of
secondary metals impacts such as mobilization of manganese, arsenic, and iron; and (2) TCE degradation
resulting from the reducing conditions imparted by the microbial activity. As a result, the appropriateness
of ISB for source area remediation remains unknown. If the source area saturated zone investigation
suggests the need for targeted remediation of the saturated soils, the potential use of ISB in addition to
SVE can be further evaluated with another pilot test including a longer follow-up monitoring period. If
there are concerns about water quality effects imparted by ISB or other source area remedies from the
pilot test, it may be appropriate to replace private Paluxy Aquifer wells (in addition to those discussed in
Recommendation 5.1.1) near the source area with Twin Mountains Aquifer wells (beyond the range of
municipal water supply lines) so that the supply wells are not adversely affected by an ISB remedy.
The cost of the ISB pilot test using the installed well network described above and testing with a
recirculation cell (pumping groundwater and reinjecting upgradient with ISB amendments added) would
be approximately $50,000.
5.3 Recommendations for Phased P&T for Plume Migration Control and Aquifer Restoration,
If Needed
The plume continues to migrate to Walnut Creek and past the Pelican Bay supply wells where
contamination was first discovered. This section provides recommendations for phased P&T for plume
migration control and aquifer restoration (as needed).
Recommendation 5.3.1: Install P&T System for Focused Hydraulic Containment Only; Include Treatment
Capacity for Full-Scale System for Potential Future Needs as Contingency
After well replacement and source area treatment and characterization, the optimization review team
assigns the next highest priority to plume migration control. The optimization review team concurs with
the approach to use P&T to provide hydraulic control of the plume. A hydraulic control system could be
similar in nature to the system with horizontal extraction wells presented in the Preliminary Design
Report (EA 2013) but would need to include the following extraction locations: EW-13 through EW-15,
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and EW-17 through EW-21. Reinj action could occur at location IW-2, as presented in the Preliminary
Design Report (EA 2013).
Benefits of Implementing Section
5.3 Recommendations
Decrease operating time frame
of P&T system by addressing
source area before installing
P&T system.
Reduce capital costs for P&T
system by focusing on plume
migration control.
Allow opportunity for aquifer
restoration through source
remediation and plume control
and potentially eliminate the
need for the full-scale P&T
system.
Based on extraction rates from previous simulations, the total
extraction rate for this system would be approximately 48 gpm.
Revisiting the groundwater model with this extraction and
injection scenario could help refine the extraction locations,
injection locations and extraction rates. To accommodate future
potential flow contributions, the groundwater treatment plant
should be designed for up to 150 gpm.
Capital costs associated with scale-up of the groundwater
treatment plant are in the range of $50,000 assuming the need
for a larger air stripper model, GAC units, pumps and piping.
Extra volume impacts on operation and maintenance (O&M)
costs for VOC treatment systems are typically relatively low.
Recommendation 5.3.2: Monitor and Evaluate Aquifer
Restoration and Only Implement Full-Scale P&T if Monitoring
Suggests P&T is Needed and Capable of Timely and Cost-
Effective Aquifer Restoration
With aggressive source removal and plume migration control, the next remedial priority would be aquifer
restoration. Progress toward aquifer restoration will begin as soon as the source area is treated because the
contaminant mass input to the plume will be reduced or eliminated. After a successful source area remedy
and several years of monitoring (five year review cycle is recommended - monitoring recommendations
are provided in Appendix C) are completed, the site team should assess if short-term aquifer restoration
has been achieved. If aquifer restoration does not meet anticipated mass reduction goals or the plume
appears to be migrating, the P&T system can be expanded to include additional capacity as described in
the Preliminary Design Report (EA 2013) (a contingency response). The groundwater treatment system
would already be designed to accommodate this additional potential flow. Therefore, only the extraction
and injection systems would need to be expanded. If aquifer restoration occurs in a sufficient time frame
following source area remediation, the extraction and injection systems do not need to be expanded, and
the P&T system can continue to operate as a containment system until plume concentrations have attained
cleanup goals. Remedy performance monitoring recommendations are described in Section 5.5 below.
5.4 Recommendations for Streamlined Groundwater Treatment Plant
Recommendation 5.4.1: Streamline Groundwater Treatment Plant to Include One Treatment Process for
VOCs
The Preliminary Design Report (EA 2013) calls for treatment of
the extracted water with filtration, chemical addition (biocide,
defoamer and scale inhibitor), air stripping with off-gas
treatment and polishing with liquid phase granular activated
carbon (LGAC). The optimization review team believes this
system is overly redundant and recommends simplifying the
treatment system to reduce long-term operation and
maintenance (O&M) costs.
The optimization review team presents two options:
Benefits of Implementing Section
5.4 Recommendations
Reduce operating costs by
streamlining groundwater
treatment system.
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Air stripping only: At an extraction rate of 48 gpm or 150 gpm, the four or six tray air stripper
rated for 500 gpm in the Preliminary Design Report (EA 2013) would be able to provide treated
water with undetectable TCE and cis-1,2 DCE concentrations with a conservative safety factor.
Eliminating the LGAC would save some construction costs. More importantly, it would reduce
O&M costs and issues associated with potential LGAC fouling from scaling caused by aeration
and costs associated with addition of the scale inhibitor. Based on the cost estimates provided in
the Preliminary Design Report (EA 2013), this approach would save approximately $20,000 per
year, but savings may actually be higher if this approach avoids problems with scaling that would
otherwise have occurred.
LGAC only: Another, more cost-effective option, which is favored by the optimization review
team, would be to provide treatment with LGAC only and eliminate the chemical addition and air
stripping. Because the water is not aerated, scaling of treatment plant equipment and the injection
well would be avoided. In addition, vapors from air stripping are not emitted, so off-gas treatment
would not be needed. The optimization review team estimates that an LGAC-only system should
operate for less than $150,000 per year (including project management) if treating 48 gpm and
less than $260,000 per year if treating 150 gpm. These estimated annual O&M costs would
represent savings of more than $250,000 per year relative to the costs identified in the
Preliminary Design Report (EA 2013). Additional cost savings could be realized if breakthrough
of cis-1,2 DCE below 70 (ig/L is acceptable to EPA and LGAC can be changed out based on TCE
breakthrough. The optimization review team would not suggest providing the treated water to
others for direct use if the cis-1,2 DCE (or TCE) is detected in the effluent below MCLs.
Currently, vinyl chloride (VC) is not present at concentrations of concern in the downgradient
plume lobes. The MCL for VC (2 (ig/L) is well below that for cis-1,2 DCE (70 (ig/L), so there
may be a concern that VC above protective concentrations could be generated from cis-1,2 DCE
present below the cleanup goal. Based on current data, however, the geochemical environment of
the aquifer does not favor the formation of VC from cis-1,2 DCE. If VC is generated as a result of
ISB treatment and transported downgradient, then the LGAC only option may not be sufficiently
protective. Releases of cis-1,2 DCE to aerobic surface water and sediments or reinjection in the
largely aerobic aquifer are unlikely to generate VC above MCLs. The optimization review team
does not consider residual cis-1,2 DCE below 70 (ig/L as a potential risk driver in effluent.
5.5 Recommendations for Remedy Performance Monitoring
Recommendation 5.5.1: Implement Remedy Performance Monitoring
The performance monitoring recommendations for each of the
remedies discussed above are provided in Appendix B.
Monitoring and Remediation Optimization System (MAROS)
Analysis Reports supporting remedy performance
recommendations are provided in Appendix C.
Recommended remedy performance metrics by remedy are
presented below. More detailed remedy performance criteria,
including specific data collection and analytical methods, target
concentration reductions and capture zones should be developed during remedy design. Monitoring
results can be compared to exit criteria (Section 5.6) to evaluate the shutdown of particular remedy
components and to help operate or optimize remedy components.
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Benefits of Implementing Section
5.5 Recommendations
Cost-effective monitoring
program and performance
metrics to optimize remedy
operation and shutdown remedy
components in a timely manner.
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SVE - The SVE system should remove source area residual mass and decrease mass discharge to
the Paluxy Aquifer overtime. Potential performance metrics should include the following:
o Mass removed by individual extraction wells and the combined system over time based
on measurements of vapor extraction rate and vapor concentrations. Total mass removed
should be compared to energy and maintenance costs to determine a cost per unit mass
value.
o Groundwater concentrations in source area monitoring wells over time relative to
baseline groundwater concentrations at the same wells. Statistical concentration trends
should be evaluated relative to baseline monitoring results. To this end, a comprehensive
groundwater monitoring event including private supply and monitoring wells is
recommended prior to initiation of source remediation to establish the baseline.
o Groundwater concentrations of VOCs (and metals after ISB treatments ([if
implemented]) in source area monitoring wells over time relative to cleanup goals.
o Mass discharge in groundwater from the source area based on interpreted groundwater
flow and contaminant concentrations in source area monitoring wells.
ISB (if implemented as a remedy amendment) - The ISB remedy, if implemented, should
significantly reduce the TCE concentrations in the source area and reduce mass discharge to the
downgradient dissolved plume to allow aquifer restoration overtime without causing
unacceptable secondary water quality issues. Secondary water quality issues may include
mobilization of metals such as manganese, arsenic, and iron; or production of odors or colors that
may have health or aesthetic impacts at downgradient water supply wells. Potential performance
metrics should include the following:
o Groundwater concentrations of VOCs in source area monitoring wells over time relative
to baseline groundwater concentrations at the same wells. (See recommendation for
baseline groundwater monitoring above).
o Mass discharge in groundwater downgradient from the source area based on interpreted
groundwater flow and contaminant concentrations in monitoring wells.
o Total organic carbon (TOC) concentrations and geochemical indicators such as oxidation
reduction potential (ORP), pH and sulfide relative to target values for attainment of
anaerobic conditions.
o Manganese, iron, arsenic and odor relative to target values for human health and aesthetic
impacts to maintain adequate water quality.
P&T system for hydraulic control - The P&T system for hydraulic control should provide
effective plume capture relative to the target capture zone to prevent continued plume migration.
A lack of capture would suggest the potential need for system upgrades. A decrease in mass
removal rates below target levels at specific locations could help evaluate shutdown of that
extraction component of the system. Potential performance metrics could include the following:
o Water levels and interpreted hydraulic capture zone relative to target capture zone.
o Statistical concentration trends and concentrations relative to cleanup goals in
downgradient performance monitoring wells to evaluate plume capture.
o Mass removal rate relative to mass discharge that would result in unacceptable plume
migration.
o Estimates of total dissolved mass in the plume and statistical trends of dissolved mass.
Aquifer restoration - TCE concentrations throughout the dissolved plume should decrease once
source remediation is implemented. Consequently, the plume area relative to specific target
concentrations should decrease overtime. Potential performance metrics could include the
following:
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o Concentration trends and concentrations relative to cleanup goals.
o Plume area that is above cleanup goals.
o Plume area that is above four times the cleanup goals.
Where concentration trends are monitored, visual analysis (concentration versus time graphs) and
statistical trend tests can be performed for groundwater data and included in Five-Year Reviews. Visual
analysis and trend tests can be performed for relevant monitoring locations with datasets with four or
more sample events. Visual analysis and a non-parametric test for trend, such as the Mann-Kendall test
can be used to track both individual well concentrations and estimates of total dissolved mass and plume
footprint for groundwater response to RAs. Semi-annual to annual sampling will generate datasets of
sufficient size to develop statistically significant trends.
Mass discharge calculations refer to estimates of the mass passing through a plane perpendicular to
groundwater flow. Estimates of mass discharge indicate the mass moving downgradient that may cause
plumes to migrate or persist for extended periods of time. Source treatment should significantly reduce
mass discharge through pre-determined cross-sectional planes perpendicular to groundwater flow. It is
recommended that mass discharge be estimated prior to source treatment, and annually after source
treatment. Significant reductions (>25 percent) in mass discharge should be apparent after source
treatment.
5.6 Recommendations for Data Management
Recommendation 5.6.1: Continue With Current Data Management Practices
Benefits of Implementing Section
5.6 Recommendations
Maintenance of data in a
readily accessible and easy to
use form.
Site data have been collected from over 135 sampling locations
since 2007. The optimization review team recommends
continuing to maintain the site database with particular attention
to accuracy of X and Y (horizontal) and Z (elevation) locational
coordinates of sampling locations, boring logs and well
construction details. Site characterization activities coinciding
with installation of the SVE system will generate data essential
to characterizing the concentration and morphology of the source of TCE. Sustained data management
will enable cumulative data to be used to support future decisions on source treatment and assess how the
plume will behave over the long term.
5.7 Recommendations for Establishing Remedy Operation Exit Criteria
Establishing remedy operation exit criteria, or performance metrics, for each remedy component can help
reduce the risk of operating a remedy past the point of effectiveness. The exit criteria are not related to the
programmatic transition from Long-Term Remedial Action to Operation and Maintenance at a Superfund
financed RA or to a decision to delete a site from the NPL, but rather are remedy-specific
recommendations developed to evaluate the cost/benefit of continued operation of each remedy
component.
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Recommendation 5.7.1: Establish Exit Criteria for Each Remedy Component
Exit criteria for each remedy should be developed by the site
team. The optimization review team provides the following
suggestions by remedy for consideration by the site team. The
performance monitoring recommended in Section 5.4 provides
the necessary information to compare with the exit criteria.
Benefits of Implementing Section
5.7 Recommendations
Criteria to help avoid operating
long-term remedies longer than
necessary.
SVE
o One potential exit criterion for the SVE system (or individual wells within the SVE
system) is a TCE mass removal rate that is small relative to the initial TCE mass removal
rate of the SVE system, such that continued operation of the system will result in
negligible mass removal relative to mass removal at startup.
o Another potential exit criterion for the SVE system can be based on a mass removal rate
relative to the current mass flux from the source area to the dissolved plume. For
example, there is a given flux of TCE mass from the source area to the dissolved plume
that could be represented by the estimated groundwater volume flow rate through the
cross-sectional area from MW-15 to MW-16 and to MW-17 multiplied by the average
TCE concentration from these three wells. A similar cross-sectional area could be
developed from the recommended monitoring wells during system installation. The exit
criterion could be to shut down the SVE system when the mass removal rate from the
SVE system is some multiple of the current mass flux rate through specified cross-
sectional area.
o TCE vapor concentrations may rebound at particular locations after a SVE well is shut
down due to diffusion of mass out of tighter subsurface material. SVE extraction wells
can be operated in pulse mode or on a rotating basis to extract the accumulated vapors.
o Relevant criteria for terminating the SVE system are discussed in the ROD (EPA 2011)
(Section 12.4) and are supported by the optimization review team.
ISB (if implemented as a remedy amendment)
o An exit criterion for a source area saturated zone remedy could be based on TCE
concentrations and mass discharge at MW-15, MW-16 and MW-17 or mass
discharge directly from source area monitoring wells.
o Another potential exit criterion could be a determination that continued source area
remediation is providing no measurable benefit or is causing unacceptable secondary
water quality issues such as exceedance of primary MCLs for arsenic in drinking
water (10 (ig/L) and secondary MCLs for manganese (50 (ig/L) for aesthetic impacts
or Texas Protective Concentration Levels (PCLs) (1.1 mg/L) for protection of human
health. Other aesthetic effects such as color or odor may also trigger reduction or
elimination of ISB treatments. Further action may be warranted to address the scope
and longevity of potential secondary water quality issues.
P&T system for plume control
o The exit criterion for a specific extraction zone within the P&T hydraulic control
remedy could be based on the TCE concentration and mass discharge at that
extraction zone relative to a predetermined threshold below which unacceptable
plume migration will not occur.
Sandy Beach Road Ground Water Plume Superfimd Site Remedial Design-Stage Optimization Review Report
Tarrant County, Texas 16
-------
P&T system for aquifer restoration
o The exit criterion or the criterion for not building the full-scale aquifer restoration
P&T system can be based on observable decreasing concentration trends within the
plume and a decreasing plume footprint over time relative to the expected decreases
that would result from P&T system installation and operation.
Additional study by the site team would be needed to help define reasonable exit criteria for the various
remedy components to help avoid unnecessary operation of these remedies.
5.8 Recommendations for Environmental Footprint Reduction
No specific recommendations have been provided for environmental footprint reduction. However,
several of the above recommendations have the potential to reduce the remedy footprint by either
streamlining the treatment process or reducing the likelihood of operating a remedy component past the
point of measureable benefit in achieving the RAOs.
Sandy Beach Road Ground Water Plume Superfimd Site Remedial Design-Stage Optimization Review Report
Tarrant County, Texas 17
-------
Table 8: Recommendation Summary
Recommendation
5.1.1 Plug, abandon and replace
water supply wells GW-9, GW-10,
GW-llandGW-39
5.2.1 Evaluate potential additional
sources during SVE system
installation
5.2.2 Characterize source area
saturated soils
5.2.3 Prioritize source area
remediation above plume
containment and aquifer restoration
5.2.4 Conduct additional ISB pilot
test to evaluate effectiveness as a
source area remedy and secondary
impacts to water quality
5.3.1 Install P&T system for
focused hydraulic containment
only but include treatment capacity
for full-scale system for potential
future needs
5.3.2 Monitor and evaluate aquifer
restoration and only implement
full-scale P&T if monitoring
suggests P&T is needed and
capable of timely and cost-effective
aquifer restoration
5.4.1 Streamline groundwater
treatment plant to include one
treatment process for VOCs
5.5.1 Implement remedy
performance monitoring
5.6.1 Continue with current data
management practices
5.7.1 Establish exit criteria for
operation of each remedy
component
%
a
H
W
c
"5
o
1
o
y
H
.j
c
i i
1 ^
5 a
it
3
VI
O
0
S -s
c .5
O !-
.- a
C 0
W fe
I
Capital
Cost
$600,000
N/A
$50 000
N/A
$50 000
$50,000
(additional
cost
associated
with scale up
or treatment
system)
N/A
N/A
$100,000
N/A
N/A
Change in
Annual Cost
(See 5. 5.1
Remedy
Performance
Monitoring)
(-$20,000)
Sandy Beach Road Ground Water Plume Superfimd Site
Tarrant County, Texas
18
Remedial Design-Stage Optimization Review Report
-------
APPENDIX A
REFERENCES
-------
APPENDIX A
REFERENCES
EA (2010a). Remedial Investigation, Sandy Beach Road Ground Water Plume Superfund Site. Lewisville,
Texas, EA Engineering for US Environmental Protection Agency Region 6.
EA (201 Ob). Feasibility Study Report, Sandy Beach Road Ground Water Plume Ground Water Plume
Superfund Site. Lewisville, Texas, EA Engineering for US Environmental Protection Agency
Region 6.
EA (2011). Technical Memorandum, qPCR and CSIA Data Evaluation. Lewisville, Texas, EA
Engineering for US Environmental Protection Agency Region 6.
EA (2013). Preliminary Design Report, Lewisville, Texas, EA Engineering, Science and Technology, Inc.
for US Environmental Protection Agency Region 6.
USEPA (2011). Record of Decision Sandy Beach Road Ground Water Plume Superfund Site. Dallas, TX,
U.S. Environmental Protection Agency Region 6.
USEPA (2012). Transmittal of the National Strategy to Expand Superfund Optimization Practices from
Site Assessment to Site Completion. Washington, B.C., U.S. Environmental Protection Agency,
Office of Solid Waste and Emergency Response (OSWER).
Sandy Beach Road Ground Water Plume Superfund Site Remedial Design-Stage Optimization Review Report
Tarrant County, Texas A-l
-------
APPENDIX B
SUPPORTING FIGURES FROM EXISTING DOCUMENTS
-------
3
o
cc
Eagle Mountain Lake
Topographic Map Source:
Adapted from Azle Quadrangle, Jx., 7.5 minute
USGS quadrangle map, 1955, photoinspected 1978
N
0 1000 2000 Feet
EA ENGINEERING,
SCIENCE, AND
TECHNOLOGY
SANDY BEACH ROAD
GROUND WATER PLUME
SUPERFUND SITE
DESIGNED BY
TM
DRAWN BY
CRS
CHECKED BY
DWR
SCALE
1:12,000
Site Location Map
DATE
09/13/2011
TASK ORDER
14342.13
FIGURE
1
-------
SANDY BEACH RD
Explanation
Designation Symbol Type
01 A Soil gas survey point
T1
Temporary boring/well
50
100 Feet
TCE mass from passive
soil gas survey (nanograms)
2,500-10,000
10,000-20,000
^H 20,000-35,000
j^H 35,000-50,000
I Above 50,000
Geophysical subsurface survey
Possible buried ferrous and
non-ferrous material
Low conductivity EM-31 quadrature
mode
Base Map Source:
Aerial photograph provided by Texas orthoimagery program 2008-2009
Notes:
EM - Electromagnetic
TCE = Trichloroethylene
O T3
_ -JJ C
ฃ* IS W TJ
(I "5 ง W
t/> Q. .2 Oi
Oro o > ^
_ C .ฃ ฐ
0 Z I |
(/) (0 C CO
s|l-&
HI > 2 C
(_5 ฃ i- *"
p S- (o (/)
1 o a)
0) z
O
LU
0
a:
LLJ
H
55
CD > ct:
>- Q LJJ
Q Z Q-
z => ;5
< o <0
o
o
z
EQ>:
LJJ Z O
LJJ < O
ZLUQ
ii|
LJJ LJJ ฃj
< O LJJ
LJJ CO I-
LU 00
Q: -<-
^
o
Q:
LJJ
Q
Q:
CO
LU
_l
<
O
CO
DO
Q
LiJ
LU
X
O
>-
DO
a:
a
DO
Q
LU
CO
LU
Q
oo
CM
i^-
oo
O
CM
LJJ I
I- 00
< O
Q
O
o
CM
ฐ
-------
( Pelican Bay 10
Pelican-Bay-06
GW;ik5 GW.16
64
Pelican Bay 7 (North)
Pelican
9553 x --- ^ Pelican Bay 12
MW-03-03 33J02
MW-27 MW-03-04
63 I 10
MW-02-01 MW-01
if v
Camp
iTimfrerlake
^ MW-43
MW-04
600
Explanation
Designation Symbol Type
MW-01 ^ Monitoring well
cw-02 o Private well
Pelican Bay 12 A Public well
T-1 ฎ Temporary boring/well
MW-17 Sample Location
<5 TCE below reporting limit
| TCE above 5 ug/L
] TCE above 50 ug/L
1200 Feet
36567 TCE concentration (|jg/L), Depth of sample (ft btoc)
Symbol color
Green Sampled November 2009
Purple Sampled June 2010
Yellow Sampled September 2010
Blue Sampled October 25, 2010
Red Sampled December 2010
Black Sampled February 2011
Cyar Sampled May 2011
Base Map Source:
Aerial photograph provided by Texas orthoimagery program 2008-2009
Notes:
3 Well not used for contouring purposes
b Well may be screened in Paluxy as well as Twin Mountain
TCE = Trichloroethylene
_C
LU C ,_
O T 0)
I- ฃ !ฑ
c
o -o >.
+= c x
= 3 =
LU
Q ^
CO
>- Q LJJ
Q Z Q-
Z => =>
< O tO
co
O
o
z
EQ>:
LJJ Z O
LJJ < O
ZLJJ~O
ii|
LJJ LJJ jjj
< O LJJ
LJJ CO I-
LU CD
cr: ซ-
^
o
oo
cc c\i
LU i^-
Q 00
on ^f
o "-
^:
CO
LJJ
LJJ
_l
<
O
CO
DO
Q
LJJ
X.
O
LJJ
I
O
>-
DO
fฃ
Q
CD
CO
LJJ
Q
O
CNJ
O
CM
CD
< O
Q
O
O
ฐ
cc:
-------
North
A
7W
'
650
M
. "~~
.
GLEN
ROSE "
.CONTACT
TD
i
-22^~
sc
CL ~T-=-
ML
SAND
^
SC
. SAND
r* ซ*
SILTSTONBSHA
=98'
MW-21
-_^
^
TD=
-E
Tfifl
I
i
h
.
T
M
C
"ซ\M
SM """7^
ML ^
SAND"^]
"CL
sc
^^^^^
'. SAND
. SP
*- 3
S?>
^ Jj*.
_SAND
SILT8TQNE
GLEN ROS
LIMESTONE
TO SHALE
!
'
^
' FORMATION
: -,
E FORMATION
SHALQSILTSTQNE
SILTBTONE
CLAY "P
F(
.8ILT
-I
; SILTSTONE
SHALE MARL
450'
0 SOD 1000 1500 2000 25
LEGEND:
PALUXY FORMATION
i pT 1 SILTY TO SANDY CLAYS. LIGHT GRAY , WHITE, PALE BROWN TO
1 - 1 YELLOWISH BROWN, PALE RED, PLASTIC
1 Mi CLAYEY SILT TO SILTY, GRAY TO PALE BROWN TO REDDISH
!MuaMl BROWN TO OLIVE YELLOW, SOFT TO STIFF, VERY FINE GRAINED
1 1 CLAYEY SAND, PINK TO YELLOWISH RED, BROWN TO LIGHT
1 su 1 REDDISH BROWN, VERY FINE TO FINE GRAINED
SILTY SAND TO SAND TO SANDSTONE, LIGHT GRAY TO PALE
1 1 YELLOW TO VERY PALE BROWN, VERY FINE TO FINE GRAINED,
1 1 UNIFORM GRAIN SIZE, GENERALLY NON-COHESIVE WITH AREAS
THAT ARE CEMENTED
VIN MOUNTAIN
)RMATION
00 30
UNDIFFE
SHELL
HASH
SAND
MW-40
,JMW-1
SAND
iSILT
ฃ
SAND
STONE
-
SILTSTQHE
CLAY
LIMESTONE
TO SHALE
I
3
TD=
4
_
TD
Z
SAND "-"%
&SILT
SAND"
STONE
SJLTBTONE
=65'
1
n
IALE/8ILTCTONE
SILTSTONE
3ILTSTONB
SILTV9HALE
-
Iw
123
tALBSILTBTONE
""> -
_J*A
--
r~ ^
TL>
'-27
ac~~~~
SM ^~
.0. S
^MT^
ซ,;
South
A'
-JWW-28
-_.
-
- ป
^
TD
M\
sc
Jฅ S, SHELL HftSW
S1.TY
SILTSTOHE MIX
ORADATJONAL
- CONTACT ';.
9ILTS
391
TONE
TD=
V-31
ic ^
.ftANOWIl).
FOSSILS
siLTsrollE
-4Q&
TD=
00 3500 4000 4500 5000
RENTIATED
SAND WITH FOSSILS AND SHELL HASH/GRAVEL, ABUNDANT
OYSTER SHELLS (GRYPHEASP). LIGHT YELLOWISH BROWN TO
PALE BROWN, SAND IS FINE GRAINED, LOOSE
TWIN MOUNTAINS FORMATION
SILT
SILTSTONE
SHALE
CLAY
GLEN RC
SILTSTONE
SHALE
LIMESTONE
SILTSTONBSILTY SHALE, CLAY REDDISH BROWN
GRAY SILT AND CLAY
SE FORMATION
CALCAREOUS SILTSTONE TO CALCAREOUS SANE
GRAY, SOME CLAY, MASSIVE TO LAMINATED, SOF
LIMESTONE, THEN INTO SHALE AND MARL WITH E
-44
^t-
- GRADATION INK
SILTSTONE
^ ^_
SILTSTONE
45'
i
i
u
1-
ฃ
b, 1
d,^^^_
.
'
TV\
7WI
i
650
,ซ/Vl
. ป**
i
i
"
ซ
XO
.
5500 6000 6500 7000 7500
WELL SCHEMATIC
etxj^jjj^^j^^^jM ^ ^^IBLD
HORIZONTAL SCALE IN FEET
20 10 0 20
VERTICAL SCALE IN FEET
VERY FINE SAND, LIGHT GREENISH
)Y SILTSTONE, LIMESTONE AND MARL, LIGHT GREENI!
T TO VERY STIFF, GRADES DOWNWARD INTO
IEPTH, LIGHT GREENISH GRAY SOFT TO VERY HARD
SOIL US
CLASSIF
- WELLS
TD=20" WELL n
cs
ICATON
;REEN
IWATER LEVEL
=PTH
Geologic Cross-Section A - A'
SANDY BEACH ROAD
GROUND WATER PLUME
SUPERFUND SITE
B?^JPk EA ENGINEERING,
W^M \ SCIENCE, AND
^HF'VF TECHNOLOGY
FIGURE 1
5 1
TASK ORDER
14342.13
DATE
09/13/2011
SCALE
AS SHOWN
CHECKED BY
TM
DRAWN BY
JRM
DESIGNED BY
TM
/? ^v
ฎ
-------
APPENDIX C
RECOMMENDED GROUNDWATER PERFORMANCE MONITORING
-------
APPENDIX C
RECOMMENDED GROUNDWATER PERFORMANCE MONITORING
Well Name
MW-15
MW-16
MW-17
MW-18
MW-24
MW-38
GW-39
Replacement
GW-01
GW-02
GW-29A
GW-24
GW-12/36
SVE Wells
OB-1
Suggested source
area wells
MW-45
Replacement
wells for GW-09,
GW-10, GW-11
GW-16
GW-19
GW-25
GW-33
MW-11
MW-12
MW-13
MW-14
GW-03 thru
GW-06
MW-07
MW-8R
MW-09
MW-10
MW-20
MW-21
MW-22
MW-23
GW-33
GW-34
Unit
Paluxy
Paluxy
Paluxy
Paluxy
Objective
Evaluate response to
source area
treatment
Delineate source
area north of
treatment zone
Evaluate plume
migration and plume
attenuation
Delineate plume,
monitor plume
migration and
remedial
performance
Parameters &
Frequency*
VOCs quarterly for 2
years during and after
SVE installation,
semi -annually after
SVE treatment
(Metals if ISB remedy
is installed)
VOCs semiannually
while SVE is
operational
VOCs semiannually
after SVE is
operational
VOCs annually
Analyses
Statistical trend
evaluation, mass
discharge
downgradient,
mass removal
versus cost of
remedy
Compare to
cleanup standards
Statistical trend
evaluation, mass
discharge
downgradient
Compare to
cleanup standards,
evaluate trends
where appropriate
Sandy Beach Road Ground Water Plume Superfimd Site
Tarrant County, Texas
C-l
Remedial Design-Stage Optimization Review Report
-------
Well Name
GW-35
GW-37
MW-25 thru
MW-39
MW-41thru
MW-45
MW-01 thru
MW-06 multiple
levels
MW-19
MW-10
MW-39
MW-40
P&T extraction
wells
SVE extraction
wells (vapor)
Unit
Paluxy
Twin
Mountain
Twin
Mountain
Paluxy
Paluxy
vapor
Objective
Delineate plume,
monitor plume
migration and
remedial
performance
Evaluate plume
migration in Twin
Mountain aquifer
Delineate plume in
Twin Mountain
aquifer
Mass removal
Mass removal
Parameters &
Frequency*
VOCs annually
VOCs semiannually
for 2 years after GW-
39 is replaced
VOCs annually
VOCs quarterly
Photoionization
detector monthly and
VOCs quarterly from
key wells for
comparison
Analyses
Compare to
cleanup standards,
evaluate trends
where appropriate
Mass discharge to
tail of plume
Statistical trend
evaluation,
comparison to
cleanup standards
Compare to
cleanup standards
Mass removal rate
Mass removal rate
A comprehensive, monitoring event is recommended prior to initiation of the source area remedies. The
monitoring network can be reduced in both well number and frequency after the 2 year remedy
performance monitoring period. If remedy installation/activation is delayed, annual monitoring is
recommended until active remedies are initiated.
Sandy Beach Road Ground Water Plume Superfimd Site
Tarrant County, Texas
C-2
Remedial Design-Stage Optimization Review Report
-------
APPENDIX D
MONITORING AND REMEDIATION OPTIMIZATION SYSTEM ANALYSIS REPORTS
-------
APPENDIX D
MAROS ANALYSIS REPORTS
Sandy Beach NPL Site Remediation Optimization
Tarrant County, Texas
-------
MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
Time Period: 10/29/2007 to 8/17/2011
Consolidation Period: Yearly
Consolidation Type: Median
Duplicate Consolidation: Average
ND Values: 1/2 Detection Limit
J Flag Values: Actual Value
Well
Source/
Tail
Number
of
Samples
Number
of
Detects
Coefficient
of Variation
Mann-
Kendall
Statistic
Confidence
in Trend
All
Samples
"ND" ?
Concentration
Trend
TRICHLOROETHYLENE (TCE)
GW-01
GW-02
GW-03
GW-09A
GW-10A
GW-11A
GW-16
GW-24
GW-25
GW-29A
GW-33
GW-34
GW-35
GW-37
GW-39
MW-02-01
MW-03-02
MW-07
MW-08R
MW-09
MW-11
MW-12
MW-13
MW-15
MW-16
MW-17
S
s
S
T
T
T
T
T
T
S
T
T
T
T
S
T
T
T
T
T
T
T
T
S
S
S
4
4
4
4
4
4
4
4
3
4
1
4
1
1
2
1
3
3
2
3
2
3
3
3
3
3
4
4
3
4
4
4
4
4
3
4
1
2
1
1
2
1
2
3
2
2
2
3
3
3
3
3
0.30
0.33
0.58
0.17
0.27
0.30
0.55
0.27
0.00
0.41
0.00
0.21
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
-6
0
-4
0
0
-4
2
2
0
0
0
-5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
95.8%
37.5%
83.3%
37.5%
37.5%
83.3%
62.5%
62.5%
0.0%
37.5%
0.0%
89.6%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
D
S
S
S
S
S
NT
NT
N/A
S
N/A
S
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 2
-------
MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
TRICHLOROETHYLENE (TCE)
Number Number
Well
MW-18
MW-19
MW-20
MW-21
MW-22
MW-24
MW-25
MW-27
MW-28
MW-31
MW-38
MW-43
MW-44
MW-45
OB-1
Note: Increasing
Source/
Tail
S
s
T
S
T
S
T
T
T
T
S
T
T
T
S
of
Samples
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
(1); Probably Increasing (PI);
of
Detects
1
2
2
2
1
2
2
2
2
2
2
1
1
1
1
Stable (S);
Applicable (N/A)-Due to insufficient Data (< 4 sampling
Coefficient
of Variation
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Mann-
Kendall
Statistic
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Probably Decreasing (PD);
Confidence
in Trend
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
All
Samples
"ND" ?
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Decreasing (D); No Trend (NT)
Concentration
Trend
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
; Not
events); Source/Tail (S/T)
The Number
of Samples and Number
of Detects shown
above are post-consolidation values.
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 2 of 2
-------
MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
Well: GW-01
Well Type: S
COC: TRICHLOROETHYLENE (TCE)
Time Period: 10/29/2007 to 8/17/2011
Consolidation Period: Yearly
Duplicate Consolidation: Median
Consolidation Type: Average
ND Values: 1/2 Detection Limit
J Flag Values : Actual Value
2.5E-01
.- 2.0E-01
E
~ 1.5E-01 -I
o
1
c 1.0E-01
8
c
O 5.0E-02 -
O.OE+00
Date
y
Mann Kendall S Statistic:
-6
Confidence in Trend:
95.8%
Coefficient of Variation:
0.30
Mann Kendall
Concentration Trend: (See
Note)
D
Data
Note:
(N/A)
Table:
Well
GW-01
GW-01
GW-01
GW-01
Increasing
Well
Type
S
S
S
S
Effective
Date
7/1/2007
7/1/2009
7/1/2010
7/1/2011
Constituent Result (mg/L) Flag
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
(1); Probably Increasing (PI); Stable (S); Probably Decreasing
- Due to insufficient Data
2.1E-01
1.6E-01
1.4E-01
l.OE-01
(PD); Decreasing (D);
Number of
Samples
1
1
1
1
No Trend (NT); Not
Number of
Detects
1
1
1
1
Applicable
(< 4 sampling events); ND = Non-detect
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 1
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MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
Well: GW-02
Well Type: S
COC: TRICHLOROETHYLENE (TCE)
Time Period: 10/29/2007 to 8/17/2011
Consolidation Period: Yearly
Duplicate Consolidation: Median
Consolidation Type: Average
ND Values: 1/2 Detection Limit
J Flag Values : Actual Value
Date
Concentration (mg/L)
A OF m -
i 5F m -
i OF m -
2 IF m -
o OF m -
1 5F m -
1 OF m .
e OF 09 -
n nR-nn .
ป
Mann Kendall S Statistic:
Confidence in Trend:
37.5%
Coefficient of Variation:
0.33
Mann Kendall
Concentration Trend: (See
Note)
Data
Note:
(N/A)
Table:
Well
GW-02
GW-02
GW-02
GW-02
Increasing
Well
Type
S
S
S
S
Effective
Date
7/1/2007
7/1/2009
7/1/2010
7/1/2011
Constituent Result (mg/L) Flag
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
(1); Probably Increasing (PI); Stable (S); Probably Decreasing
- Due to insufficient Data
3.2E-01
3.3E-01
4.1E-01
1.7E-01
(PD); Decreasing (D);
Number of
Samples
1
1
1
1
No Trend (NT); Not
Number of
Detects
1
1
1
1
Applicable
(< 4 sampling events); ND = Non-detect
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 1
-------
MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
Well: GW-03
Well Type: S
COC: TRICHLOROETHYLENE (TCE)
Time Period: 10/29/2007 to 8/17/2011
Consolidation Period: Yearly
Duplicate Consolidation: Median
Consolidation Type: Average
ND Values: 1/2 Detection Limit
J Flag Values : Actual Value
Date
y
y
Concentration (mg/L)
1 9F 09 .
1 OE-02
o OF m -
R OF m -
4 nF m .
n nR-nn .
*
*
4
Mann Kendall S Statistic:
-4
Confidence in Trend:
83.3%
Coefficient of Variation:
0.58
Mann Kendall
Concentration Trend: (See
Note)
Data
Note:
(N/A)
Table:
Well
GW-03
GW-03
GW-03
GW-03
Increasing
Well
Type
S
S
S
S
Effective
Date
7/1/2007
7/1/2009
7/1/2010
7/1/2011
Constituent Result (mg/L) Flag
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
(1); Probably Increasing (PI); Stable (S); Probably Decreasing
- Due to insufficient Data
l.OE-02
1.2E-02
5.3E-03
2.5E-03 ND
Number of
Samples
1
1
1
1
(PD); Decreasing (D); No Trend (NT); Not
Number of
Detects
1
1
1
0
Applicable
(< 4 sampling events); ND = Non-detect
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 1
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MAROS Mann-Kendall Statistics Summary
Project: Sandy Beach
Location: Azel Texas
User Name: MV
State: Texas
Well: GW-29A
Well Type: S
COC: TRICHLOROETHYLENE (TCE)
Time Period: 10/29/2007 to 8/17/2011
Consolidation Period: Yearly
Duplicate Consolidation: Median
Consolidation Type: Average
ND Values: 1/2 Detection Limit
J Flag Values : Actual Value
ion (mg
Concen
Date
y
y
1 OF 01 -
Q OF 09 -
6.0E-02
4 OF n? -
2 OE-02
n DF+nn .
*
*
4
Mann Kendall S Statistic:
Confidence in Trend:
37.5%
Coefficient of Variation:
0.41
Mann Kendall
Concentration Trend: (See
Note)
Data Table:
Well
GW-29A
GW-29A
GW-29A
GW-29A
Note: Increasing
Well
Type
S
S
S
S
Effective
Date
7/1/2007
7/1/2009
7/1/2010
7/1/2011
Constituent Result (mg/L) Flag
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
TRICHLOROETHYLEN
(1); Probably Increasing (PI); Stable (S); Probably Decreasing
(N/A) - Due to insufficient Data
3.8E-02
1.1E-01
8.2E-02
6.4E-02
(PD); Decreasing (D);
Number of
Samples
1
1
1
1
No Trend (NT); Not
Number of
Detects
1
1
1
1
Applicable
(< 4 sampling events); ND = Non-detect
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 1
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MAROS Percent of Mass by Well
Project: Sandy Beach User Name: MV
Location: Azel Texas State: Texas
TRICHLOROETHYLENE (TCE) 8/17/2011 [fb
1 n
i j
1 n
1U
i-
I nfl Hi
Well
GW-01
GW-02
GW-03
GW-09A
GW-10A
GW-11A
GW-16
GW-24
GW-25
GW-29A
GW-33
GW-34
GW-35
GW-37
1 n [
inn ~ n nL_j Ln _ Jn J ~_
^ ^
Area (ft2) Mass (mg) Percent of Mass Percent of Area
7,138.92 124.93 1.79 0.65
10,598.35 315.30 4.53 0.97
25,179.61 11.02 0.16 2.30
30,567.44 294.21 4.23 2.79
49,939.81 166.05 2.38 4.56
39,650.03 194.29 2.79 3.62
25,922.23 190.53 2.74 2.37
62,856.16 648.99 9.32 5.74
52,328.82 9.16 0.13 4.78
2,924.48 32.75 0.47 0.27
56,163.95 14.74 0.21 5.13
8,636.99 3.78 0.05 0.79
5,429.79 6.65 0.10 0.50
36,590.94 259.98 3.73 3.34
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 1 of 2
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MAROS Percent of Mass by Well
Project: Sandy Beach
Location: Azel Texas
Well
GW-39
MW-02-01
MW-03-02
MW-07
MW-08R
MW-09
MW-11
MW-12
MW-13
MW-15
MW-16
MW-17
MW-18
MW-19
MW-20
MW-21
MW-22
MW-24
MW-25
MW-27
MW-28
MW-31
MW-38
MW-43
MW-44
MW-45
OB-1
Area (ft2)
8,124.72
41,766.73
39,951.44
53,209.45
21,036.51
61,886.17
10,059.15
34,436.30
34,048.66
11,140.38
3,591.95
3,969.19
14,043.83
25,415.14
28,951.54
23,541.24
9,635.60
13,284.72
46,962.61
20,908.84
48,724.04
23,640.97
76,836.22
17,178.88
987.77
6,374.07
2,231.26
1,095,864.9
Mass (mg)
366.12
7.31
160.80
242.10
58.90
27.08
35.21
192.84
518.39
54.59
54.06
131.98
6.14
1,334.29
31.92
118.65
4.22
20.57
262.99
150.02
596.87
19.03
268.93
4.63
0.75
5.91
16.82
6,963.5
User Name:
State:
Percent of Mass
5.26
0.10
2.31
3.48
0.85
0.39
0.51
2.77
7.44
0.78
0.78
1.90
0.09
19.16
0.46
1.70
0.06
0.30
3.78
2.15
8.57
0.27
3.86
0.07
0.01
0.08
0.24
100
MV
Texas
Percent of Area
0.74
3.81
3.65
4.86
1.92
5.65
0.92
3.14
3.11
1.02
0.33
0.36
1.28
2.32
2.64
2.15
0.88
1.21
4.29
1.91
4.45
2.16
7.01
1.57
0.09
0.58
0.20
100 [fl]
MAROS Version 3.0
Release 352, September 2012
Saturday, June 22, 2013
Page 2 of 2
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