vvEPA
E PA/600/R-18/103
GROUNDWATER TECHNICAL
SUPPORT CENTER (GWTSC)
ANNUAL REPORT
Fiscal Year 2016 (FY16)
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Acknowledgements
The Groundwater Technical Support Center (GWTSC) would like to acknowledge the contributions from ORD
scientists for their efforts in support of the GWTSC's mission. The GWTSC extends a thank you to our numerous clients
in the Office of Science Policy, Office of Land and Emergency Management, Office of Superfund Remediation and
Technology Innovation, and the EPA Regions, particularly the Superfund Technology Liaisons (STLs), the On Scene
Coordinators (OSCs) and their management for their support. The GWTSC would also like to recognize the exemplary
support provided by its contractor, CSS-Dynamac, and their subcontractors and consultants. Finally the GWTSC
extends special thanks to everyone that provides document reviews, responds to technical request phone calls, and
provides all other manners of assistance.
Cover photo: Installation of vadose zone sampling devices at Corvallis, Oregon field site.
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Abstract
GWTSC
Groundwater
Technical Support Center
The Groundwater Technical Support Center (GWTSC) is part of
the Groundwater, Watershed, and Ecosystem Restoration Division
(GWERD), which is based in the Robert S. Kerr Environmental Research
Center in Ada, Oklahoma. The GWERD is a research division of EPA's
National Risk Management Research Laboratory (NRMRL). The GWTSC
is one of an interlinked group of specialized Technical Support Centers
that were established under the Technical Support Project (TSP). The GWTSC provides technical support on issues
related to groundwater. Specifically, the GWTSC provides technical support to EPA and State regulators for issues
and problems related to:
1. Subsurface contamination (contaminants in groundwater, soils and sediments).
2. Cross-media transfer (movement of contaminants from the subsurface to other media such as surface water
or air).
3. Restoration of impacted ecosystems.
The GWTSC works with Remedial Project Managers (RPMs) and other decision makers to solve specific problems at
Superfund, RCRA (Resource Conservation and Recovery Act), Brownfields sites, and ecosystem restoration sites.
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Table of Contents
Acknowledgements i
Abstract ii
Introduction 1
The GWTSC Mission: What Does the GWTSC Do? 2
Implementing the GWTSC Mission 2
The GWTSC Team 3
GWTSC Technical Support Avenues 4
GWTSC Technical Support Concentration Areas 4
Subsurface Contamination 4
Cross-media Transfer 5
Ecosystem Restoration 5
Center for Subsurface Modeling Support 6
Contact Information for Requesting Technical Support 8
Technical Support Activity Examples 9
Bioremediation 9
Chem Central Superfund Site 9
Williams Air Force Base 10
In Situ Chemical Oxidation (ISCO) 11
General Electric 220 South Dawson Street Facility 11
Picayune Wood Treating Site 12
Modeling, Screening 13
McCormick and Baxter Superfund Site 13
Shepley's Hill-Ft. Devens Superfund Site, No. 6 14
Center for Subsurface Modeling Support 15
Groundwater Discharge to Bay St. Louis 15
Thermal Treatment 16
Lonsdale Bleachery Site 16
T H Agriculture & Nutrition L.L.C. (THAN) Site 17
Monitored Natural Attenuation (MNA) 18
Kirtland Air Force Base 18
General Motors Components Holdings Site 19
Permeable Reactive Barriers (PRB) 20
Eckles Road Site 20
GWTSC Technical Transfer Special Projects 21
Occurrence and Prevalence of 1,1 DCE as a Breakdown Product of TCE 21
Sustainable and Healthy Communities (SHC) Project 3.61 -Contaminated Sites
Progress and Future Directions 22
GWTSC Technical Support by the Numbers 24
Contaminants at GWTSC-Supported Sites 25
Remedies at GWTSC-Supported Sites 26
Technical Support Memoranda/Activities 27
FY'16 Highlights for Technical Support 28
About the Groundwater, Watershed, and Ecosystem Restoration Division (GWERD) 47
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Introduction
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(The GWTSC Mission: What Does the GWTSC Do?
GWTSC Focus Areas:
Subsurface contamination
Cross-media transfer of
contaminants
Ecosystem restoration
Feedback/
Applied
Science/Field
Implementation
The Technical Support
Project knowledge cycle
drives the GWTSC mission.
GWTSC provides technical support to EPA and State regulators for issues and problems
related to:
• subsurface contamination (contaminants in groundwater, soils and sediments),
• cross-media transfer (contaminant fluxes from groundwater to other media such
as surface water or air), and
• ecosystem restoration issues.
As part of the TSP, the GWTSC utilizes the TSP knowledge cycle to organize
support efforts focused on three main components:
1. Interpreting and applying ORD research to agency decisions:
providing expert technical support personnel skilled at understanding and
communicating the state of the science to Agency decision-makers so the EPA's
program offices have in-house access to technical expertise and research results.
2. Moving research results to field applications:
developing user friendly approaches and channels for providing the current
scientific understanding and consensus best practices to managers and field
implementation personnel to guide field decision-making and practical application.
3. Analyzing results of field activities to orient and guide research:
continually evaluating the results of applying state of the art ORD research to field
activities so that ORD researchers have real time feedback on field applications of
their research.
Implementing the GWTSC Mission
GWTSC partners with EPA Program and Regional staff and other decision makers to
provide technical assistance for characterization and remediation issues for CERCLA,
RCRA, Brownfields, Concentrated Animal Feeding Operations (CAFOs), and ecosystem
restoration.
The following three fundamental remediation and restoration functions are supported
by GWTSC expertise and guidance:
Planning and Implementing Site Investigation and Remediation:
• site characterization
• remedial investigations
• feasibility studies
• identification and selection of remedial alternatives
• remedy performance monitoring
Choosing and Applying Conceptual and Mathematical Models:
• identifying appropriate environmental modeling software and modeling
implementation approaches
• critical evaluation of site-specific modeling efforts
Assessing and Implementing New and Innovative Technologies:
Oversight assistance and technical support of new/innovative technologies for
treatment of contaminated soils/groundwater, and restoration of sensitive ecosystems
• design
• testing
• pilot and full-scale implementation
• performance evaluation
Technical Assistance for:
CERCLA
RCRA
Brownfields
CAFOs
Ecosystem Restoration
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The GWTSCTeam
GWERD's Technical Assistance and Technology Transfer Branch (TATTB) provides the
core members of the GWTSC technical support team. Other branches of GWERD
(including the Subsurface Processes and Protection Branch (SPPB), the Watershed,
Ecosystem, and Subsurface Research Branch (WESRB) and field support staff from the
Technical Assistance and Technology Transfer Branch (TATTB)) supply expertise as
needed.
CSS, the technical support contractor for GWTSC, provides specialized expertise to
address technical support questions and conduct field operations, and also provides
access to additional expertise via subcontractors, consultants, and academia.
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GWTSC Technical Expertise
Hydrogeologists
Geochemists
Ecologists
Microbiologists
Environmental Engineers
Mathematical Modelers
Geographical Information Systems (GIS) Specialists
Organic Chemists
Inorganic Chemists
Analytical Chemists
Technical Writing and Training Specialists
The Center for Subsurface Modeling Support (CSMoS, a modeling-focused component
of the GWTSC), provides support for environmentally-related subsurface modeling
applications, as well as support for some publicly available groundwater models (a
list of these models is found below). GWERD modeling specialists and contractors are
available to provide support.
EPA hydrologist measuring groundwater
elevation in a monitoring well.
EPA soil scientist measuring zeta potential and
electrophoretic mobility of colloids and nanoparticles
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GWTSC Technical Support Avenues
Site-specific technical
guidance:
Formal or informal
interactive approaches
related to specific
CERCLA, RCRA,
Brownfields, or
ecosystem restoration
sites
GWTSC provides technical support through:
Site-Specific Technical Guidance
• Site activity review memoranda
• Conference calls
• Email
• Site visits and meetings
Technical Transfer
• Training, including workshops, demonstrations, conferences, and expert panels
• Publications, such as issue papers, fact sheets, and technical guidance documents
Technical transfer:
Training and
publications related to
specific subsurface or
ecosystem restoration
issues
GWTSC Technical Support Concentration Areas
Subsurface Contamination
GWTSC/GWERD is the EPA technical support and research leader for subsurface
processes, characterization, remediation and monitoring.
GWTSC/GWERD areas of expertise
for contaminants in groundwater, soils
and sediments include:
Contaminant sources
Plume behavior
Transport and fate of contaminants
Subsurface geology and stratigraphy
Subsurface geochemistry
Subsurface microorganism
populations and processes
Groundwater model suitability
and application
Sampling and analysis tools
Bench and pilot studies, and
scaleup
Performance monitoring
Holistic/sustainable approaches
GWERD field personnel collecting water samples.
GWTSC/GWERD has produced almost 150 EPA publications related to technical
guidance and understanding of subsurface contamination and modeling issues, plus
many more journal articles, books, etc. Some of the latest publications are listed under
the Scientific and Technical Publications heading found at the end of this Annual
Report. Many more publications can be accessed at the EPA National Library Catalog
webpage for searching the various EPA libraries, including the GWERD library in
Ada, OK. (https://www.epa.gov/nscep)
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Cross-media Transfer
Cross-media Contaminant Transfer from Groundwater to Surface Water
Cross-media transfer refers to movement of contaminants from groundwater and
subsurface media to surface water or air. GWTSC cross-media transfer expertise
includes vapor intrusion (VI) issues, which relate to transfer of contaminants from
groundwater to subsurface air, and then movement of the contaminants into
structures. For instance, movement of chlorinated solvents or their degradation
products from shallow
groundwater into buildings is
a common issue at many sites
where chlorinated solvents are
found in shallow groundwater
under or near buildings.
Also, GWTSC provides support
and guidance for dealing with
transfer of contaminants from
groundwater to surface water
such as lakes, streams, and salt
water bodies.
Commercial/Industrial
Residential
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Ecosystem Restoration
Ecological restoration has
been defined as "return of
an ecosystem to a close
approximation of its condition
prior to disturbance." The
GWTSC provides support
for restoration of impacted
ecosystems such as riparian
zones and streams, and
wetlands to enhance
their health, integrity and
sustainability.
Restoration of a 3,000-foot stretch of Big Spring Run in West Lampeter Township, PA.
In FY'16, Dr. Richard Wilkin, a GWERD
environmental geochemist, provided assistance
to Project Manager Jannine Jennings regarding
methods to understand the geochemical
processes that are important for control of
phosphorus movement along downgradient
flow pathways towards the Portneuf River at the
Eastern Michaud Flats Superfund Site.
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Center for Subsurface Modeling Support (CSMoS)
The Center for Subsurface Modeling Support (CSMoS), an integral part of GWTSC,
promotes and supports the use of public domain groundwater and vadose zone
modeling software for understanding and evaluating subsurface processes,
characterization, and remediation, in addition to providing a website with links for
downloading supported models and associated documentation such as manuals and
case studies, CSMoS takes technical support questions from the general public as well
as from government agencies, and provides direct technical support to EPA and State
decision makers for applications of the subsurface models.
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CSMoS models currently available can be downloaded at the EPA Methods, Models,
Tools, and Databases for Water Research webpage under the Models tab.
(https://www.epa.gov/water-research/methods-models-tools-and-databases-water-research)
The most commonly downloaded models include the simple screening models
Biochlor, Bioscreen, REMFuel, Bioplume III, FOOTPRINT, REMChlor, and OWL.These
models are easy and straightforward to use for anyone with a basic knowledge of
subsurface processes and hydrogeology.
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Description of Models Distributed by CSMoS
Model Name
Model Name and Version
CSMoS
Center for Subsurface
Modeling Support
Model Description
2DFATMIC
2DFATMIC 1.0
2-D subsurface flow/transport
3-D subsurface flow/transport
3DFATMIC
3DFATMIC 1.0
1-D Domenico screening model
BIOCHLOR
BIOCHLOR 2.2
BIOPLUME
BIOPLUME II 1.1
2-D USGS MOC transport
BIOPLUME
BIOPLUME III 1.0
2-D USGS MOC transport with Windows GUI
BIOSCREEN
BIOSCREEN 1.4
3-D Domenico transport
CHEMFLO
CHEMFLO 1.3
1-D vadose zone numerical transport
CZAEM
Capture Zone Analytic
Element Model
Estimates Capture Zones
FOOTPRINT
FOOTPRINT 1.0
2-D transport of BTEX and ethanol
GEOEAS
GEOEAS 1.2.1
Geostatistical analysis
GEO PACK
GEO PACK 1.0.e
Geostatistical analysis
HSSM-DOS
HSSM-DOS 1.1
Multiphase LNAPL flow/transport
HSSM-SPN
HSSM en Espanol 1.2.e
Multiphase LNAPL flow/transport (Spanish version)
HSSM-WIN
HSSM-Windows 1.2.e
Multiphase LNAPL flow/transport
MDFL MAN
MODFLOW Manuals
MODFLOW practice problems
MO FAT
MO FAT 2.0.a
2-D multiphase transport
MT3D
MT3D 1.11
3-D numerical transport
OWL
OWL 1.2
Monitoring well locator
PESTAN
PESTAN 4.0
Simulate leaching of pesticides
REMChlor
REMChlor 1.0
Simulate transient plume remediation
REMFuel
REMFuel 1.0
Simulates the transient effects of groundwater source and plume
remediation for fuel hydrocarbons
RETC
RETC 1.1
Estimate soil model parameters
RITZ
RITZ 2.12
Simulate vadose zone transport
STF
Soil Transport and Fate
Database 2.0
Database of behavior of organic and inorganic chemicals in soil
UTCHEM-PC
UTCHEM-PC 9.0
3-D multiphase flow/transport
UTCHEM-
UNIX
UTCHEM-UNIX
3-D multiphase flow/transport
VIRULO
Virulo 1.0
Probabilistic virus leaching model
VLEACH
VLEACH 2.2.a
1-D vadose zone leaching model
WhAEM
WhaEM
Analytical element capture zone model
WhAEM 2000
WhAEM2000 3.2
Analytical element capture zone model
WHPA
WHPA2.2
Finite-difference capture zone model
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Contact Information for Requesting
David Burden, Ph.D.
Director, GroundwaterTechriical Support Center (GWTSC)
burden.david@epa.gov (580)436-8606
Mary Gonsoulin, Ph.D.
Chief, Technical Assistance and Technology Transfer Branch (TATTB)
gonsouiin.mary@epa.gov (580)436-8616
How to Request Technical Support
Define the specific questions you need answered. "Does the Enhanced
Bioremediation Work Plan call for measuring the appropriate geochemical
parameters?" is a good, specific question. "What does GWTSC think about the
Enhanced Bioremediation Work Plan?" is difficult to answer, and the answer
may not narrow it down to the answers you really need. Provide questions that
help GWTSC experts focus on those specific issues that are important to you for
your site.
Second, gather the site documents needed to help GWTSC understand the
hydrogeology, contaminants, plumes, and geochemistry/microbiology at the
site. Site characterization data, monitoring reports, work plans, site maps and
cross sections are almost always needed. Electronic copies are best except for
large maps. Spreadsheets of monitoring data (i.e., in addition to tables in PDF
format) are often helpful to ailow GWTSC experts to slice and dice the data for
analysis.
Finally, contact David Burden by phone, email, or through the ORD TSC
Share Point site (https://usepa.sharepoint.eom/sites/ORD_Work/ETSC/_
layouts/15/start.aspx#/default.aspx) to initiate a technical support request.
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Technical Support Activity Examples
Bioremediation
in FY'16, GWTSC provided technical support to 13 sites where
bioremediation is used or proposed.
Chem Central Superfund Site
Dr. David Burden (GWTSC Director) and Dr. Daniel Pope advised
EPA Project Manager Pamela Molitor on a proposed shutdown
of an extraction well at the Chem Central Superfund Site in
Wyoming, Ml. Contaminants in Site groundwater include benzene,
toluene, ethyl benzene, and xylenes (BTEX), trichloroethene
(TCE), 1,2-dichloroethene (1,2-DCE), and vinyl chloride (VC).
Remedial approaches for the Site include a plume containment
system (extraction of groundwater from purge wells), and natural
attenuation.
The Site remediation management team wanted to shut down
one of the purge wells located at the toe of the plume, as not
contributing materially to remediation progress. In general, GWTSC
concurred with the rationale presented for shutting down the purge
well. However, because the groundwater extraction system is a
major factor in determining the mix of contaminants, geochemistry,
and contaminant concentrations found along the plume, as well
as groundwater and contaminant flow paths, GWTSC indicated
that any changes (such as the proposed shutdown of the purge
well) should be approached with caution. GWTSC recommended
that shutdown of the purge well be accompanied with continued
detailed monitoring to ensure that any trends in the contaminant
mix, contaminant concentrations, geochemistry, and groundwater
flow can be quickly detected. Also, GWTSC recommended that the
purge well be kept in operational condition in case restart is needed
to maintain plume control.
FY'l 6 Technical Support for Bioremediation
Remedies
1. Caldwell Trucking
2. Chem Central Superfund Site
3. DuPont Pompton Lakes Works, No. 7
4. Former Solutia Inc. - J.F. Queeny Plant
Site
5. Hunter's Point Naval Shipyard, No. 6
6. Kenosha Engine Plant
7. Kirtland Air Force Base
8. Maryland Sand, Gravel and Stone
9. Quanta Resources Corporation
Superfund Site
10. Savage Well Municipal Water Supply
Superfund Site, No. 8
11. South Municipal Water Supply
12. T.H. Agricultural & Nutrition, LLC
13. Williams AFB, No. 8
Google Maps (2017) provides an aerial view of the Chem Central site.
Site Background:
The 2-acre Chem Central
site is located in Wyoming,
Michigan. Since 1957,
Chem Central has
distributed industrial
chemicals from the site.
Between 1957 and 1962,
hazardous wastes entered
the ground at the facility
through a construction
flaw in a pipe used to
transfer liquids between
rail cars and bulk storage
tanks. The leak resulted
in soil and groundwater
contamination. Following
cleanup, operation and
maintenance activities are
ongoing.
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Williams Air Force Base Site
Site Background:
The former Williams AFB
is located in Maricopa
County and lies within
the boundaries of the City
of Mesa, AZ. The former
Williams AFB was a flight-
training base that was first
activated in 1941. ST012 is
the location of the former
Liquid Fuels Storage Area
where fuel storage and
distribution operations
involving aboveground
and underground
tanks and lines were
conducted from 1941
until the fuel storage and
distribution system was
decommissioned in 1991.
Equipment and structures
relating to the fuel
storage and transmission
operations with ST012
have been removed.
Soil and groundwater at
ST012 have been affected
by releases of fuels from
the historic operations.
Williams AFB was placed
on the EPA National
Priorities List in 1989.
The base officially closed
in 1993. The Air Force
transferred the property
(including ST012) to the
Phoenix-Mesa Gateway
Airport Authority in 2008.
Dr. Eva Davis (GWERD) reviewed the Draft Addendum #2, Remedial Design and Remedial
Action Work Plan for Operable Unit 2, Revised Groundwater Remedy, Site STO12, for
Carolyn D'Almedia, EPA RPM. The Williams Air Force Base site has groundwater
contamination with jet fuel-based light non-aqueous phase liquid (LNAPL) and
dissolved contaminants including benzene. Enhanced bioremediation (EBR) and MNA
is proposed to remediate LNAPL and dissolved contaminants remaining following
steam enhanced extraction of LNAPL.
Aerial view of the Williams Air Force Base Site.
GWTSC conclusions and recommendations included:
• The Addendum does not demonstrate that the planned EBR can meet the goals
of achieving conditions that would allow natural attenuation to reach soil cleanup
criteria in the remedial timeframe.
• The design of the EBR system in Addendum #2 is only conceptual in nature,
A complete design must include, at a minimum, the following information:
-Terminal electron acceptor (TEA) injection rates, time for injections to occur,
injection/extraction ratios, predicted travel time of sulfate to extraction points,
criteria to convert to recirculation system if desired TEA distribution is
not achieved
- Weir tank to be used, size; design of particle filtration and granular activated
carbon systems, controls/interlocks of these systems
- Which injection wells will receive TEA solution via direct pumping, which require
portable mixing tanks, size of mixing tank
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In Situ Chemical Oxidation (ISCO)
In FY'16, GWTSC provided technical support to 10 sites where ISCO is used or
proposed.
In ISCO deployment, a chemical oxidant is introduced into the subsurface
to transform groundwater or soil contaminants into less harmful chemical
components. Among the oxidants used are sodium and potassium
permanganate (NaMn04, KMn04), hydrogen peroxide (H202), and sodium
persulfate (Na2S208).
General Electric 220 South Dawson Street Facility
Google Maps (2017) provides a photo of the General Electric 220 South
Dawson Street Facility.
FY'16 Technical Support for ISCO
Remedies
1. Arkwood Superfund Site, No. 5
2. Atlantic Fleet Weapons Training
Area -Viques, Puerto Rico
3. Eckles Road Site
4. Former Solutia Inc.-J.F. Queeny
Plant Site
5. General Chemical Corporation
6. General Electric 220 South
Dawson Street Facility
7. Kenosha Engine Plant
8. Letterkenny Army Depot
9. Picayune Wood Treating Site
10. Sonford Products Site
Site Background
The former General Electric Aircraft Engines Facility was located at 220 South Dawson Street, Seattle, Washington. GE
occupied the premises from 1949 to 1997, with the manufacture and repair of aircraft engine parts from 1959 to 1994.
During that time, hazardous substances were spilled or leaked from sumps and tanks, and entered underlying soils
and groundwater. The main site contaminants include solvents trichloroethylene (TCE), tetrachloroethylene (PCE),
and 1,1,1 - trichloroethane (1,1,1 -TCA), as well as fuels and oils.
Some or all of these contaminants are found in the indoor air, soil, and groundwater beneath the 220 South Dawson
Street building.The contaminants have also migrated in the groundwater to the west at least as far as Utah Avenue
South. Some TCE in the soils and groundwater below the 220 South Dawson Street building changed to a gas and
moved upwards through the soil, into the building workspaces.
Vacated by GE in 1997, the building is now occupied by another tenant.
Dr. Scott Huling (GWERD) reviewed the Persulfate in-Situ Chemical Oxidation Bench Test
Report for Dean Yasuda , EPA Project Manager for the site, where persulfate is being
evaluated forTCE remediation.
GWTSC conclusions and recommendations included:
• The large volume, low concentration reagent injection design is preferred to the
small volume, high concentration design.
• Injecting low oxidant volume will likely result in inadequate oxidant distribution
and post-injection dispersal within the radius of influence, insufficient oxidant
contact and oxidant loading, and incomplete treatment.
Image of persulfate ion,
released to public domain by
authors Jynto and Ben Mills
via Wikimedia Commons.
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Site Background:
The Picayune Wood Treating
site is located in Picayune,
Mississippi, it includes
the area where various
timber and lumber-related
operations took place from
the early 1900s to 1999.
EPA placed the site on
the National Priorities List
(NPL) in 2004 because of
contaminated groundwater,
soil and sediment resulting
from facility operations.
GWERD/GWTSC ISCO
guidance documents:
Ko, S., S.G. Huling, and B. Pivetz.
2012. Ground Water Sample
Preservation atln-Situ Chemical
Oxidation Sites - Recommended
Guidelines. Ground Water Issue
Paper. Office of Research and
Development.
Huling, S.G., S, Ko, and B.
Pivetz. 2011. Groundwater
Sampling at ISCO Sites: Binary
Mixtures of Volatile Organic
Compounds and Persulfate.
Ground Water Monitoring &
Remediation. Spring 2011,
31 (2):72-79.
Huling, S.G., and B.E. Pivetz.
2006. In-Situ Chemical
Oxidation. Engineering Issue
Paper. Office of Research
and Development, U.S.
Environmental Protection
Agency. EPA/600/R-06/072.
Picayune Wood Treating Site
Dr. Scott Huling (GWERD) reviewed the Draft Groundwater 100 Percent Optimized
Groundwater Design Report for Michael Taylor, EPA RPM. ISCO deployed in a
recirculating reagent injection system was proposed to remedy contamination from
wood treating operations.
GWTSC conclusions and recommendations included:
• Sodium or potassium permanganate are recommended oxidants for site
remediation, based on oxidant demand, bench scale study results, oxidant
persistence in the subsurface, water chemistry, and oxidant delivery options.
• Groundwater recovery wells located close to the contaminant containment cell
(a slurry wall) may cause a groundwater gradient to be established so that
contaminants could be moved from within the containment cell to outside
the ceil. The system should be designed so that an inward gradient is maintained
at all times in the containment cell.
• The proposed recirculation system may encounter problems with required
treatment of the extracted groundwater before reinjection, and with plugging
of the injection wells with particulates.
• Recirculation systems move groundwater and reagents through the most
permeable portions of the subsurface, which is not necessarily where the
contaminants are located.
• Direct emplacement of the ISCO reagents should be strongly considered in
preference to a recirculation system.
Stocksttll
Vatspar
Treating
SOUTH SlOf
iLEWENT^fly SCHOOL
Site Boundary Drainage Ditch — Mill Creek Public Access
Picayune Wood Treating Site (Image courtesy of Mississippi Department of
Environmental Quality.)
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Modeling, Screening
FY'16 Technical Support
for Groundwater Flow and
Contaminant Transport Modeling
1. Bailly Generating Station
2. Chem-Dyne Superfund Site, No. 6
3. Cyprus Tohono Mine Superfund
Site, No. 2
4. Eastern Michaud Flats, FMC OU,
No. 4
5. Frontier Fertilizer SF Site
6. Los Alamos National Lab, No. 4
7. Maryland Sand, Gravel and Stone
8. McCormick & Baxter SF Site
9. Picillo Farms Superfund Site, No. 8
10. RACER Moraine - Former GM
Engine & Assembly Plants, No. 2
11. US Steel - Minntac Site
Assessment
12. Yerington Mine Site, No. 8
13. Shepley's Hill-Ft. Devens
Superfund Site, No. 6
Modeling of groundwater flow and contaminant transport is necessary for
careful characterization of most groundwater contamination sites, and for
evaluation and implementation of remedies. For FY'16, GWTSC provided
detailed comments on modeling efforts for 13 sites.
McCormick and Baxter SF Site
Dr. Randall Ross (GWERD) and Dr. Milovan Beljin (CSS) provided EPA Project
Manager Patricia Bowlin with an analysis of the Final Groundwater Modeling
Report. Specific questions considered in the analysis include whether the
groundwater model assumptions were valid and whether the values of the
model input parameters were reasonable.
GWTSC conclusions and recommendations included:
• The groundwater model for the site is relatively simple and due to the
lack of data, it is not rigorously calibrated.
• The horizontal and vertical discretization of the model domain is
sufficiently fine considering the available data and the purpose of the
model.
• MODFLOW and MT3DMS are the appropriate codes for the processes
being simulated.
• The steady-state flow conditions are acceptable considering the lack
of data for a transient simulation.
• Considering the objectives of the model, the model can serve as a
useful management tool.
Retorts • Main
Wood Processing
Area
Treated Wood
Storage Areas
Oily Waste Pond Area
60ft a
lOOftB
150 ftc
200 ft n
250 ft e
Sources of Contamination at
McCormick & Baxter Superfund Site.
(Image from EPA Region 9 fact sheet
"McCormick & Baxter Superfund Site.")
Legend
I v Movement of
~ ^ graundwatervNAPI.
contamination
A Aquifer ZcatKs
(depth shown in feet
below ground surface
¦ DKAPL
tcniamirunicfl
~ Contamination
O Groundwater flow
Site Background:
The McCormick and Baxter Creosoting
Company, Portland Plant, Superfund
Site is located adjacent to the Willamette
River in Portland, Oregon and addresses
contamination of soil, groundwater, and
river sediments stemming from creosoting
operations between 1944 and October
1991. The site lies between a bluff and the
river and consists of 43 acres of land and
over 15 acres of river sediments. The site
is bordered by industrial properties along
the river and by a residential areas on
the bluff. A Burlington Northern Railroad
spur crosses the western portion of the
property, and a Union Pacific Railroad
crosses the northeastern portion of the
site below the bluff. The site consists
of three operable units for addressing
contamination: one each for soil,
groundwater, and river sediments.
13
-------
Site Background:
The former Fort Devens Army
Base is located 35 miles west
of Boston in the towns of
Ayer, Shirley, Lancaster and
Harvard, Massachusetts. The
base was active until it closed
in 1996 under the Defense
Base Realignment and
Closure Act of 1990. Wastes
generated by the facility have
contaminated soil, sediment
and groundwater at the
site. Long-term cleanup and
monitoring are ongoing.
Shepley's Hill-Ft. Devens Superfund Site, No. 6
Dr. Milovan Beljin (CSS), Dr. Randall Ross and Steve Acree (GWERD) reviewed
the Shepley's Hill Groundwater Model Revision Summary and Preliminary Results
Memorandum for the Shepley's Hill -Ft. Devens Superfund Site, No. 6.
GWTSC conclusions and recommendations included:
• The current groundwater flow model represents a significant improvement
over previous modeling efforts. However, the groundwater flow model
appears to lack the necessary accuracy to satisfy the stated objective of
evaluating the performance of the existing groundwater capture system.
• The clustering of residuals may be an indication of a systematic bias in the
model. In this case, the clustering of negative residuals downgradient of the
landfill and positive residuals throughout the landfill is an indication that the
conceptual site model, as applied to the flow model, may need to be
revisited.
• The memorandum did not evaluate the degree to which the model
represents observed hydraulic gradients. The magnitude and sometimes
the direction of simulated hydraulic gradients appear to differ from observed
gradients in several locations, including the areas beneath the landfill, near
Red Cove, and in parts of the North Impact Area.
BOSTON
5HL-23/:
SML-20
phase
.' 1986
• (SHEPLEY'S HILL LANDFILL). ' • . '
5HL-19
Hig
~ *
SHM-93-01A ^
PHASE
W- .' iv—a
1991
. " PHASE III
¦ 1989
Mu-92-04
32«-M-0«k
.m t-32>*-S2H>2
Shepley s Hill Landfill.
(Images from www.epa.gov/supeiiund/devens.)
14
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MISSISSIPPI
Subsurface Modeling Support (CSMoS)
CSMoS is a subunit of GWTSC dedicated to providing basic technical support (related
to availability, installation and use of the models) for a set of free modeling software
packages provided or linked through the CSMoS website. These models are listed
in the CSMoS model table (Description of Models Distributed by CSMoS) under the
Center for Subsurface Modeling Support (CSMoS) section heading above. Most of the
technical support requests are by email through the CSMoS website. In FY'16, CSMoS
provided technical support for 30 inquiries.
Groundwater Discharge to Bay St. Louis
Bay Saint Louis map generated by USGS - The National Map.
Bay Saint Louis bridge. (Photo courtesy of U.S. Department of
Transportation, Federal Highway Administration.)
GWTSC provided support for determining approaches for assessment of a PCE and
TCE groundwater contaminant plume moving toward Bay St. Louis. It is expected
that the plume will eventually discharge into the Bay, so it was desired to evaluate
how the plume will discharge into the Bay (the area of the discharge, the maximum
concentrations of PCE and TCE expected, and how the PCE and TCE would be
expected to be dispersed by dilution and Bay currents).
GWTSC conclusions and recommendations included:
• MODFLOW is an industry standard numerical model for this type of application.
MODFLOW can be set up as steady state or transient; the transient modeling
approach could be used to incorporate modeling of changing conditions such as
seasonal effects or tidal influences.
• Chemical transport models, such as MT3D or RT3D, can be coupled with
MODFLOW to allow for modeling of contaminant movement, including reactive
transport (RT3D). Since the PCE/TCE-specific degradation/sorption parameters are
well-known, MT3D would be useful for modeling their movement.
• In addition, dilution/attenuation of chemical concentrations to the nearby
drainage feature can be used to estimate groundwater discharge. Surface water
models such as SMS can incorporate the discharge rate/concentration
information from the groundwater flow model and can be used to estimate
movement of the discharge in the surface water body.
15
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FY'16 Technical Support
for Thermal Treatment
Remedies
1. Beede Waste Oil
Superfund Site, No. 6
2. Cleburn Street Well SF
Site
3. Diaz Chemical
Corporation
Superfund Site
4. Former Solutia Inc.-
J.F. Queeny Plant Site
5. Hunter's Point Naval
Shipyard, No. 6
6. Lonsdale Bleachery
Site
7. Paducah Gaseous
Diffusion Plant
Thermal Treatment
In FY'16, GWTSC provided technical support to 11 sites where thermal treatment is
used or proposed.
Lonsdale Bleachery Site
Dr. Eva Davis evaluated the use of in situ thermal remediation at the Lonsdale
Bleachery Site in Lincoln, Rhode Island, for Sherry Banks, the EPA On-Scene
Coordinator (OSC). The site is contaminated with Bunker C fuel oil, and oil and/or an
oily sheen is discharged to the adjacent Blackstone River at times of low river flow.
GWTSC conclusions and recommendations included:
• Short term groundwater pump tests should be
conducted to obtain estimates of the
hydraulic conductivity of the soils at the site,
which can be used to determine the required
pumping rates for establishing an inward
gradient.
• Bench scale tests should be conducted on the
oil to determine its viscosity as a function
of temperature, the percent volatiles as
a function of temperature, and the treatment
temperature and time required to remove
enough of the more volatile compounds to
render the remaining oil free of sheen-causing
compounds.
Skimming oil from water, Lonsdale
Bleachery Site.
Because the site is adjacent to the Blackstone River, and only separated from the
river by an historic retaining wall, steam enhanced extraction (SEE) and electrical
resistance heating (ERH) are not appropriate for the site. Injected steam may
'daylight'at the retaining wall if SEE were used, and stray current may reach the
river if ERH were to be used.
The oil contaminated Blackstone River
sediments are not amenable to thermal
remediation of any type. Water
flowing through the sediments would carry
the applied heat to the river and downgradient.
Additional characterization be completed to
determine the aerial extent of the oil;
Laser Induced Fluorescence (LIF) or the TarGost
tool may be an economical means of obtaining
the required data.
Boom collecting oil on the river, Lonsdale
Bleachery Site.
8. Savage Well
Municipal Water
Supply Superfund
Site, No. 8
9. South Municipal
Water Supply
10. T.H. Agriculture &
Nutrition, LLC
(THAN) Site
11. Williams AFB, No. 8
Site Background:
The Lonsdale Bleachery Site is the location of a former textile mill abutting the Blackstone River in Lincoln, Rhode Island. In 2004, a
petroleum odor and sheen were observed downstream on the Blackstone River, prompting an emergency response conducted by
the Rhode Island Department of Environmental Management. The former Lonsdale Bleachery was found to be the source of the
sheen. At the request of Rl DEM, EPA mobilized to the Site to conduct oil spill response activities pursuant to an OPA 90 Project Plan.
These cleanup activities focused on identifying and removing the source(s) of the oil release to the Blackstone River. These activities
were completed in the spring of 2007.
Oil continues to seep into the river, particularly during periods of low water levels, from the base of a granite block retaining wall in
the former fuel storage and boiler area of the mill. A Site Investigation is underway to determine the nature and extent of the seeps.
16
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T.H. Agriculture & Nutrition, LLC (THAN) Site
Dr. Eva Davis reviewed the Supplemental LNAPL Work Plan for the T.H. Agriculture
& Nutrition, LLC (THAN) Site in Albany, Georgia, for Marcia O'Neal, EPA RPM. The
Supplemental Work Plan describes proposed field work to fill data gaps in the
characterization of the THAN site by obtaining additional Rapid Optical Screening Tool
(ROST) data to determine the extent of LNAPL.
GWTSC conclusions and recommendations included:
• Proposed locations for additional ROST borings appear to be appropriate; however,
it is not clear that the work plan includes all of the step-out locations that are likely
to be needed in order to fully define the extent of the contamination.
• More step-out locations may be needed depending on the results of some of the
proposed borings.
• The ROST borings will be limited in depth to the weathered limestone, but
it is not clear that vertical contaminant migration is limited by the competent
limestone bedrock. Deeper borings are required to determine the vertical extent
of contamination.
• In addition to the proposed hydrolysis experiments at 85°C, it is also recommended
that soil samples be heated to 100°C for a week to determine the removal
efficiency for all compounds at this temperature. If this experiment does not
demonstrate adequate removal of the contaminants, additional experiments can
be undertaken at higher temperatures, such as 150°C, to determine the
temperature required to meet the soil cleanup criteria for this site.
EPA "Cleanups In
My Community
Map" marks
location of THAN
site.
Site Background:
The 7-acreT H Agriculture &
Nutrition Company (THAN)
facility is located in Albany,
Georgia. From the mid-1950s
until 1967, the site was used
by other companies for the
storage and formulation of
pesticides. Typical activities
for formulating pesticides
included preparation of dry
and liquid formulations, and
blending pesticides with
solvents. THAN purchased the
site in 1967 and continued
pesticide formulation
operations until 1978.The
site was used by THAN as
a storage and distribution
center until 1982. EPA placed
the site on the National
Priorities List (NPL) in 1989
because of contaminated
ground water, sediment and
soil resulting from facility
operations.
GEORG A
Google Maps (2017) provides a street-side view of the T.H. Agriculture & Nutrition, LLC (THAN) Site.
17
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FY'16 Technical Support
for Monitored Natural
Attenuation Remedies
1. Chem Central
Superfund Site
2. DuPont Pompton
Lakes Works, No. 7
3. East Mount Zion
Landfili
4. Former England Air
Force Base, No. 2
5. Frontier Fertilizer
6. General Motors
Components Holdings
7. Kirtland Air Force
Base
8. PuchackWellfield
Superfund Site, No. 2
9. RACER Moraine -
Former GM Engine &
Assembly Plants, No. 2
10. Savage Weil
Municipal Water
Supply Superfund
Site, No. 8
11. South Municipal
Water Supply
12. Williams AFB, No. 8
Site Background:
The Bulk Fuels Facility is
located in the northwestern
portion of Kirtland Air Force
Base (AFB) in Albuquerque,
New Mexico.The Facility and
associated infrastructure
operated from 1953 until
1999. During this time, the
fueling area was separated
into a tank holding area
where bulk shipments of
fuel were received and a
fuel loading area where
individual fuel trucks were
filled. Kirtland AFB removed
the facility from service in
1999 due to discovery of
underground leakage.
Monitored Natural Attenuation (MNA)
In FY'16, GWTSC provided technical support to 12 sites where MNA is used or
proposed.
Kirtland Air Force Base
Dr. David Burden (GWTSC), Dr. John Wilson (CSS) and Dr. Daniel Pope (CSS) provided
technical support for characterization and remediation of a groundwater plume at
the Kirtland Air Force Base (AFB) in Albuquerque, NM. Releases of aviation fuels have
produced a plume of ethylene dibromide (EDB) in groundwater on portions of Kirtland
AFB and the city of Albuquerque. To evaluate the impact of the EDB plume on water
supply wells in the area, EPA Region 6 built a three dimensional transport and fate
model, but the model did not include any contribution from biodegradation of EDB in
groundwater or abiotic reactions of EDB in groundwater.
GWTSC conclusions and recommendations included:
• Observations made on releases of leaded motor gasoline can be used to evaluate
the EDB plume at Kirtland AFB.
• Rate constants for anaerobic biodegradation of EDB in laboratory studies and
field studies can explain the apparent attenuation of EDB in a segment of the
plume between the most downgradient well in the LNAPL area and the next
set of wells farther downgradient in the plume, in this segment of the plume, fuel
hydrocarbons are available to support production of hydrogen and acetate, which
are needed by the bacteria that degrade EDB.
• Rate constants for aerobic biodegradation of EDB in laboratory studies and field
studies are not consistent with the limited attenuation in concentrations of EDB
further downgradient of the LNAPL area. Aerobic biodegradation does not explain
attenuation of EDB in the plume at Kirtland AFB.
• Due to the groundwater temperature in the aquifer, rate constants for neutral
hydrolysis of EDB are relatively large. Neutral hydrolysis may bring concentration
of EDB in the plume to the Maximum Contaminant Level (MCL) before the plume
reaches a receptor well.
• Consider the contribution of
anaerobic biodegradation.
Run computer simulations
of the impact of EDB to
receptor wells that use the
highest concentration of EDB
in the monitoring wells that
are downgradient of the
LNAPL area, as opposed to
simulations that use the
highest concentrations
in the LNAPL source area.
• Consider the contribution
of neutral hydrolysis. Add a
rate constant for neutral
hydrolysis to the computer
simulations.
18
Frame from Kirtland Fuel Plume Conceptual Site Model
Animation, New Mexico Environment Department.
(https://www.youtube.com/watch?v=pitrlcbYGdo&feature=youtu.be)
-------
General Motors Components Holdings Site
Site Background:
The site was industrially
developed in 1946.
Historically, operations at
the site have involved the
manufacture of automotive,
aircraft, and diesel engine
components. Production
activity included chrome and
cadmium plating.
Originally known as the
Diesel Equipment Division of
General Motors, the facility
has, through the years, been
a part of the Rochester
Products Division, AC
Rochester Division, and the
Energy & Chassis Division of
Delphi.
Currently it is one of
four plants that make up
the GMCH consolidated
subsidiary of General
Motors and encompasses
approximately 96 acres with
1.8 million square feet of
building space. Operations
include metal grinding,
machining, plating, and
washing.
Delphi Automotive Systems,
LLC signed a Voluntary
Corrective Action Agreement
with EPA on September 17,
2002.
Dr. David Burden (GWTSC) and Dr. Daniel Pope (CSS) reviewed the Final Revised
Corrective Measures Proposal for the General Motors Components Holdings Site,
Wyoming, Ml, for Donald Heller, EPA RPM. Site groundwater is contaminated with TCE;
daughter products cis-1,2-dichloroethene (cis-DCE) and VC; BTEX; polynuclear aromatic
hydrocarbons (PAHs); and other contaminants.
GWTSC conclusions and recommendations included:
• The Final Revised Corrective Measures Proposal indicates "Site data indicate
that downgradient migration of chlorinated solvents north of the Site is being
held in check by processes of natural attenuation (adsorption and
biodegradation) which continually act to remove groundwater contaminant
mass." Therefore, natural attenuation processes are relied on to control and
remediate the off-Site plume; such reliance is effectively implementation
of an MNA remedy.
• Geochemical data to show what attenuation processes might be important
in contaminant attenuation have not been provided. Groundwater geochemical
data suitable for evaluation and performance monitoring of a MNA remedy should
be acquired and presented in reports to allow for evaluation of Site remedial and
monitoring activities.
• Given that contamination is still present on-Site, and moving off-Site to maintain
the contaminant plume, it is apparent that source control measures (i.e., removal)
have not been effective for stopping off-Site migration of contaminants. In
addition, the groundwater extraction system appears to be ineffective in
controlling off-Site migration of contaminants.
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surface water
plan and Google Maps-providi
aerial view.
19
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FY'16 Technical
Support for
Permeable Reactive
Barrier Remedies
1. ATI Wah Chang
Facility
2. Eckles Road Site
3. Grenada
Manufacturing
4. Savage Well
Municipal Water
Supply Superfund
Site, No. 8
5. South Municipal
Water Supply
Site Background:
GM is the past and/
or present owner/
operator of the site. The
property encompasses
approximately 120 acres
on the western edge
of Livonia Ml. The GM
Delphi Chassis Division
manufactured bumpers,
coils and leaf springs, and
struts at the property from
1953 -2000. The facility
was demolished in 2000-
2001, leaving concrete
floor slabs, a security fence
along the perimeter, and
a groundwater collection/
treatment operations
building in the southwest
corner.
Corrective measures
include installation of a
French drain collection
system, treatment system
and barrier wall to control
off-site migration of
chromium and nickel-
impacted groundwater,
and an in-situ treatment
system of TCE-impacted
groundwater,
Permeable Reactive Barriers (PRB)
In FY'16, GWTSC provided technical support to five sites where PRBs are in use.
Eckles Road Site
Dr. Richard Wilkin reviewed the Area 7ISCR Pilot Study Summary Report for the Eckles
Road Site in Livonia, Michigan, for Greg Rudloff, EPA RPM. Remediation at the site is
focusing on reduction of groundwater concentrations of chromium and nickel. In-situ
chemical reduction of chromium and nickel by sodium dithionite injections is planned,
along with installation of a zero valent iron (ZVI) permeable barrier for polishing
groundwater after in-situ reduction,
GWTSC conclusions and recommendations included:
• Generally, the proposed in-situ reduction approach is favorable for coupling with
a ZVI permeable barrier, because the excess reducing reagents, which would have
a negative impact on the PRB, are expected to be consumed before encountering
the PRB.
• A complete evaluation of the likely groundwater composition that would
encounter the PRB should be performed before selecting the design buffer
distance between reductant injections and the PRB.
Google Maps (2017) provides art aerial view of the Eckles Road Site.
construction
20
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GWTSC Technical Transfer Special Projects
Occurrence and Prevalence of 1,1 DCE as a Breakdown Product of TCE
Problem: 1,1 -DCE can be a product of abiotic degradation of 1,1,1 -TCA, but may also
be a breakdown product of trichloroethene (TCE).
Question: At any given site, how can it be determined whether any 1,1-DCE present is
a product ofTCE degradation, or 1,1,1-TCA degradation?
Solution: GWTSC carefully evaluated the literature discussions of the provenance of
1,1 -DCE, and came to the following conclusions.
There are three important fates of 1,1,1-TCA: (1) it can undergo a biological reductive
dehalogenation to produce 1,1 -dichloroethane (1,1 -DCA), (2) it can undergo a
biological elimination reaction to produce vinyl chloride, and (3) it can undergo an
abiotic elimination reaction to produce 1,1-DCE.
There are two relevant fates for TCE: (1) it can undergo the reductive dehalogenation
reaction to produce all three DCE isomers, or (2) it can undergo an abiotic elimination
reaction to produce chloroacetylene. Because 1,1-DCA cannot be formed from TCE, it
is indicative of the former presence of 1,1,1-TCA.
The figure below below compares the ratios of concentrations of 1,1 -DCE and c/'s-DCE
in groundwater that (1) contained TCE but no indication of the presence or former
presence of 1,1,1 -TCA to the ratio in water that (2) contained detectable concentrations
of 1,1,1 -TCA or its reductive dechlorination product 1,1 -DCA.
If 1,1,1-TCA or 1,1-DCA were present, there was on average higher relative
concentrations of 1,1-DCE to cis-DCE compared to the case where 1,1,1-TCA and 1,1-
DCA are not detected. However, there is considerable overlap in the distribution of
the two ratios. Significant concentrations of 1,1-DCE were produced in water where
TCE was the only likely precursor. In some cases, the ratio of 1,1-DCE to c/'s-DCE
approached unity, even in the absence of detectable concentrations of 1,1,1-TCA and
1,1 -DCA. Therefore, it can be concluded that the presence of 1,1 -DCE at significant
concentrations relative to c/'s-DCE cannot be taken as conclusive evidence of 1,1,1-TCA
being the parent compound of the 1,1-DCE.
100000
10000
1000
100
0.1
• 1,1,1-TCA or 1,1-DCA detected
01,1,1-TCA or 1,1-DCA not detected
/
Concentrations of 1,1-DCE
compared to cis-DCE in
groundwater.
Oo
•o0
QX>
oo °o%
8
°0 OCD*5
0.1
10 100 1000 10000 100000
cte-DCE (ng/L)
21
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Sustainable and
Healthy Communities
(SHC) Program
Research
SHC develops user-
friendly knowledge,
data, and tools to
help all communities
and stakeholders
to make optimal
economic, societal,
and environmental
decisions.
Sustainable and Healthy Communities (SHC) Project 3.61 - Contaminated Sites
Progress and Future Directions
Problem: Focusing EPA research on key points of the Sustainable and Healthy
Communities (SHC) research program.
Question: How can the SHC research program provide the knowledge, data, and tools
that communities must have to meet current needs in sustainable ways, so that current
and future generations will be able to meet their needs in economically viable, socially
just, and healthful ways?
Sustainable and
Healthy Communities
STRATEGIC RESEARCH ACTION PLAN
2016-2019
of Contaminated Sites;
Materials Management
Sustainable & Healthy Communities Research Program
rramttosdpUnary Inie^raton
wejh*, Euajrtte*** *t»l Idff
SYSTEMS APPROACH to ACHIEVING SUSTAIN ABILITY
Total Resource Impacts & Outcomes (TRIO) Applied to Decisions
Affecting Communities
Solution: The SHC research program constructs Research Action Plans (RAPs) for
each of the SHC program goals. Each project consists of interrelated tasks; each task is
composed of a set of research efforts. The Sustainable and Healthy Communities (SHC)
Project 3.61-Contaminated Sites Progress and Future Directions document provides a
concise discussion, with examples, of SHC research and other efforts such as technical
support carried out under:
Task 2: Contaminated Groundwater Research
Task 3: Contaminated Sediments Research
Task4: Vapor Intrusion Research
ORD research on contaminated groundwater addresses known or anticipated
knowledge gaps related to the characterization and restoration of contaminated
groundwater resources. Research in Task 2 concentrates on the following focus areas:
• High Resolution Characterization: Improve application and interpretation of
high resolution groundwater characterization technologies such as modeling and
geophysical tools.
• Inorganic Groundwater Contaminants: Research on inorganic groundwater
contaminants and associated inorganic contaminant remediation technologies.
• Geophysics for Groundwater Characterization: Advance the educated and
effective adoption of geophysical technology to manage contaminated
groundwater.
• Flux Based Site Management: Characterize contaminant flux and mass discharge,
as well as groundwater flux (i.e., groundwater velocity) across a specific chosen
area in the subsurface.
22
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• Back Diffusion: Understand the role that diffusion of contaminants from low
permeability zones back into the groundwater (back diffusion) plays in plume
persistence, essential for effective and protective cleanup of contaminated sites.
• In Situ Chemical Oxidation: Develop and evaluate updated approaches for use of
ISCO for groundwater treatment technologies and strategies.
• Emulsified Zerovalent Iron: Summarize a source zone treatment study of dense
non-aqueous phase liquid contaminants at a contaminated site using emulsified
zerovalent iron.
• Organic Constituent Leaching Methodologies: Understand the ability of organic
contaminants to leach from waste material and to transport into groundwater.
SHC has designated six focus areas for Task 3 Contaminated Sediments Research.
• Passive sampling: Improve the analytical technology and develop guidance on
how to use the resulting data within the Superfund decision-making process.
• Bioaccumulation: Understand the linkages between contaminant concentrations
in sediment and fish tissue concentrations.
• Remedy effectiveness: Evaluate the effectiveness of sediment remediation
alternatives and associated impacts for meeting Remedial Action Objectives at
Superfund sites.
• Source identification: Develop methods, metrics, and approaches to identify,
track, and apportion contaminant sources.
• Restoration effectiveness: Develop long-term assessment methods, metrics,
and guidance to characterize, monitor, and maintain habitat restoration following
remediation and restoration actions.
• Measuring toxicity: Revise EPA's Methods for Measuring the Toxicity and
Bioaccumulation of Sediment-associated Contaminants with Freshwater
Invertebrates.
Focus areas for Task 4: Vapor Intrusion include:
• Vapor pathways: Understand distribution and movement of volatile contaminants
from groundwater through soil to soil surface/subslab, and into a
residence/building.
• VI Characterization: Evaluate short-duration screening to induce maximum vapor
intrusion.
• Mitigation systems: evaluate effectiveness of mitigation systems to reduce or
eliminate vapor intrusion.
• Sampling materials: Determine influence of tubing type used to collect soil gas
samples.
• Sampling probe/well installation: Determine time required to reach dynamic
concentrational gas equilibrium after installation has been completed.
• Timing of sampling events: evaluate use of simple, inexpensive, and rapid
measurement devices to predict when peak vapor concentrations will occur.
23
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GWTSC Technical Support by the
Sources of
technical supports
requests
Rl(9)
Directly
EPA Headquarters;
EPA Regional Offices;
states/state
environmental agencies;
US Territories;
foreign countries
CSMoS website
environmental consultants;
individual federal, state, or
municipality
personnel/regulators;
academics; students
Long-term Remediation
Process for
SF/RCRA/Other Sites
. Characterization
G "4
... Remedy Selection
w
T Remedy
5 Implementation
C Performance
"4 & Monitoring
Long-term
GWTSC Support
CSMoS(30)"
f Requests:
EPA Regions & CSMoS
EPA Headquarters & EPA
Regional Offices are the
primary sources of
technical support .
\ requests. /
R10(4)
R9(6)
R8(l) R7(3)
R6(6)
0R(1) PA(2) AR(1) AZ(1)
0H(1) % \ I / CA(
NY(3)
DE(1)
NV(1)
NM(3),
NJ(5)
f Requests:
States
GWTSC receives more
technical support requests
from states with
historically large industrial
bases due to the higher
number of Superfund and
RCRA sites in those states. .
*Requests through CSMoS charted
separately from Regions/States. CSMoS
requests may or may not be directly
related to Region/State. CSMoS requests
are often from individuals, not federal or
state regulators.
**GWF: Groundwater Forum.
NH(5)
NE(1)
MT^ MS(3) MO(l)
MN(1
24
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Contaminants at GWTSC-Supported Sites
Others
(14%)
Pesticides (2%)
PCBs {2%)n
Radwaste (2%)*»J
PCP/Creosote/MGP J
PAHs
Less Common
Wood treating wastes
[containing pentachlorophenol
(PCP) or creosote]
Manufactured gas plant
wastes [tars, oils, cinders, coke
and ash]
Radioactive materials
[such as uranium]
Polychlorinated Biphenyls
[PCBs]
Pesticides
[Including DDT;
1,2-dibromoethane;
1,2-dichloropropane;
1,2,3-trichloropropane;
l,2-dibromo-3-chloropropane]
' Most Common ^
Chlorinated solvents;
hydrocarbons (BTEX & other
fuel hydrocarbons);
metals/metalloids (including
arsenic, lead, mercury); and
k various PAHs) /
Metals
(20%)
Least Common ("Others")
l,2-dibromo-3-chloropropane
1,2-dibromoethane
1,2-dichloropropane
1,2,3-trichloropropane
1,4-dichlorobenzene
1,4-dioxane
acetone
acid mine drainage
bis(2-ch!oroethyl)ether
bis(2-ethylhexyl)phthalate
boron
brine
carbon tetrachloride
chlorobenzene
dioxins
fu rans
n,n-diethylaniline
p-chlorobenzotrifluoride
phosphate
Royal demolition explosive (RDX)
sulfate
tetrahydrofuran
Chlorinated Solvents
(27%)
Hydrocarbons
(17%)
For many of these "Other"
contaminants, minimal field
experience data is available
on environmental transport
and fate.
GWTSC undertakes detailed
investigation of the
literature to determine
environmental transport
properties, susceptibility to
biotic and abiotic
degradation, interactions
with other contaminants,
appropriate sampling and
analysis techniques, etc., in
order to properly evaluate
characterization,
remediation, and monitoring
approaches.
-------
Remedies at GWTSC-Supported
Permeable Reactive SVE/Air
Barriers and Barrier Sparging
Walls (6%) (2%)
MNA
(16%)
Thermal (14%)
Bioremediation
(18%)
K *
Most Site
Remedy Plans
are multi-
component
* 5*
^ * v
Coordination
of multiple
remedial
approaches
can be
complex
Pump &
Treat (30%)
Remedies may
be applied
simultaneously
ISCO
(14%)
or sequentially.
Technical support must consider
the effectiveness and efficiency of each individual remedy
AND
how the remedial approaches applied at the site interact and
affect each other as site management progresses from initial
remedy implementation to final remedial efforts and site closure.
EXAMPLE
Initial remediation efforts:
1. Thermal for source removal and control
2. Pump & Treat for plume control and
capture
3. Enhanced Bioremediation for treatment
of main body of groundwater plume
Final remediation and polishing:
1. Monitored Natural Attenuation
Potential Issues/Interactions:
1. High temperatures of thermal treatment
affect subsurface microbial activity
2. P&T affects distribution of natural
electron acceptors distribution of
bioremediation agents
3. Bioremediation enhancement changes
geochemistry which affects MNA
processes
26
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ical Support Memoranda/Activities
FY16 Technical Support Memoranda and Related Activities
by Region and FY Quarter
Technical
Support
Request
GWTSC Responses
• Review Memoranda
• Conference Calls
• emails
• Meetings
• Site Visits
f I <8 J? is n 2 ' -x
5 3 § g
M Uj in
Fourth Quarter
/ Third Quarter
y Second Quarter
First Quarter
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
NAtfQNAi. RISK
-------
FY16 Highlights for TechmsaiKUHKOjtt
Technical Assistance Region IX: On October 22,2015, Dr. Eva Davis (GWERD) provided
technical review comments to RPM Lily Lee on the "Draft NAPL Treatment Pilot Study
Completion Report for Installation Restoration Site 03, Former Oily Waste Ponds,
Parcel E, Hunters Point Naval Shipyard, San Francisco, California." The objective for
the in situ thermal remediation (ISTR) treatability study was to evaluate the ability
and cost-effectiveness of ISTR to extract and treat all mobile nonaqueous phase
liquid (NAPL) within the target treatment zone (TTZ), which is consistent with the first
remedial action objective (RAO) for the site. The second RAO for the site is to prevent
or minimize the discharge of groundwater with total petroleum hydrocarbon (TPH)
concentrations greater than 1,400 pg/l into the Bay. While the first RAO was largely
met by the ISTR pilot study, the second RAO was not, as the TPH concentration in all
heated wells increased by as much as two orders of magnitude. In order to meet the
second RAO, greater reductions in soil TPH are needed than can likely be accomplished
using a hot water flood as was performed in this treatability study. In light of this,
consideration should be given to not specifying which thermal technology is to be
used for the full scale remediation, but allowing all of the thermal vendors to bid
based on what they believe their technology can achieve at this site, as compared to
the site RAOs. The Report states that dense nonaqueous phase liquid (DNAPL) was
not detected on the site until summer 2013, while the ISTR pilot system was being
installed. Tables show that DNAPL was detected in five of the twelve wells that were
probed after the ISTR pilot. The presence of DNAPL over approximately the entire
northwestern portion of the IR-03 site is a significant change to the original Conceptual
Site Model, which assumed only the presence of LNAPL. The implications of the
presence of widespread DNAPL for the CSM and planned full scale remediation should
be discussed.
Technical Assistance Region X: On October 23,2015, Dr. Richard Wilkin (GWERD)
provided technical review comments to RPM Jannine Jennings and Bernie Zavala,
Hydrogeologist, on the "Work Plan for Additional Groundwater Geochemistry
Studies Phosphoric Acid Plant Area, Simplot OU, Eastern Michaud Flats Superfund
Site, Pocatello, Idaho,"dated October 2015.The comments focus on the proposed
investigation of geochemical conditions in groundwater in the Phosphoric Acid Plant
(PAP) area of the J.R. Simplot Don Plant located near Pocatello, Idaho. The Work Plan
includes components of groundwater sampling and analysis, mineral collection and
analysis, and geochemical modeling. A key outcome of the proposed work is to be able
to prevent future mineral fouling of extraction pumps and maximize water withdrawal
of the Dense Aqueous Phase Liquid (DAPL). It is recommended that anion samples be
filtered prior to analysis because the concentration data will be used as input data for
aqueous speciation modeling. It is also recommended that Barium be added to the list
of metals for analysis. It is proposed that X-ray Diffraction (XRD) analysis will be used as
the primary method to identify mineral precipitates. This choice of analytical method
is appropriate. However, it is suggested that other techniques be considered for
characterizing the mineral precipitates. Geochemical modeling will be conducted with
the Geochemist's Workbench software package. It is possible that the solids that form
in the site groundwater will not be well represented in some geochemical databases
and this could potentially complicate modeling applications. It is recommended that
"Flash Diagrams" be developed. Such diagrams show mineral masses that precipitate,
as well as solution saturation states, when two fluids are mixed in varying proportions.
It is suggested that different ion activity models be examined.
28
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Technical Assistance Region I: On November 3,2015, Dr. Randall Ross (GWERD) and Dr.
Robert Ford (LRPCD) provided RPM Carol Keating information on slug tests performed
in wells located within and downgradient of the Shepley's Hill Landfill at Fort Devens
in Devens, Massachusetts. The majority of the tests were performed during August
and October 2015. At locations where the hydraulic conductivity of aquifer materials
was estimated to be greater than 50 ft/d, the tests were conducted using procedure
RSKSOP-256.This procedure is based on recommendations derived from Butler (1997).
The procedure utilizes air pressure and vacuum to initiate instantaneous changes
in hydraulic head within the well, combined with high frequency monitoring of the
aquifer response using data loggers and pressure transducers. At locations where the
hydraulic conductivity of aquifer materials was estimated to be less than 50 ft/d, the
tests were conducted either using the pneumatic techniques of procedure RSKSOP-256
or solid PVC slugs as specified in procedure RSKSOP-260. The aquifer response
data were analyzed using the methods of Bouwer and Rice (1976) or, in the case of
underdamped/oscillatory responses, Springer and Gelhar (1991). The estimates of
hydraulic conductivity derived from these analyses significantly enhance the coverage
available to support the ongoing groundwater flow model refinement.
Technical Assistance Region X: On November 6,2015, Dr. Scott Huling (GWERD)
provided technical review comments to Dean Yasuda, Washington State Department of
Ecology, on the"Persulfate In-Situ Chemical Oxidation Bench Test Report, GE 220 South
Dawson St. Facility."Two injection designs were presented. Based on a critical review
of this document in context with the bench study report, it is recommended that
the large volume, low concentration design is preferred relative to the small volume,
high concentration design. Overall, injecting low oxidant volume will likely result
in inadequate oxidant distribution and post-injection dispersal within the radius of
influence, insufficient oxidant contact and oxidant loading, and incomplete treatment.
It is recommended that the data and method used to calculate oxidant demand are
re-evaluated. It was reported that the groundwater was spiked with a TCE saturated
solution to a target concentration of 1 mg/L. But it appears theTCE amended to the
system was the only source of TCE in the test reactors and that the soil did not appear
to be contaminated. In the Report, it is evident that the CVOCs were oxidized mostly
within 2 days, but up to 5-7 days. In the field, the TCE will be partitioned between
the aquifer solids and the aqueous phase, where a much greater fraction is generally
measured in the solid phase media. Chemical oxidation under this condition must
target both the aqueous and solid phaseTCE. Consequently,TCE oxidation will be
more challenging as it involves TCE mass transfer between these phases. The main
purpose for identifying this issue is that the mass transfer processes will likely limit
ISCO efficiency and require longer oxidation periods and multiple oxidant injections
than what occurred in the bench scale testing. Although 10-30 g/L persulfate sounds
reasonable, the field conditions will present greater ISCO challenges than what were
encountered in the bench study.
Technical Assistance Region III: On December 2,2015, Dr. Dominic DiGiulio (CSS),
under the direction of Dr. David Burden (GWERD), provided a technical review of the
Bioventing System at the Maryland Sand, Gravel, and Stone Site, Elkton, Maryland,
for RPM Debra Rossi. A review of the closure framework, monitoring protocols, and
sampling (soil-gas and ground-water) has been conducted. As a result of this review,
a series of recommendations were provided. It is recommended that the existing
United States Environmental Protection Agency (EPA) bioventing design framework,
with modification for site-specific conditions, be utilized. Other recommendations
include installation of vapor probe clusters, leak-testing during soil-gas sampling,
and documentation of field methodology. Also, flux measurement at the surface
29
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or VOC monitoring in vapor probes near the surface could be used to ensure that
biodegradation is the major mass loss mechanism of remedial activities. A conservative
tracer (e.g., helium or a fluorocarbon) could be introduced in injection wells to
evaluate VOC reduction as a result of dispersion. Consideration should be given
to supplementing remedial design with gas sparging and dual vapor extraction
(DVE). Gas sparging and DVE (vacuum enhanced hydraulic gradient) would improve
dewatering and enable vapor capture.
Technical Assistance Region IX: On December 10,2015, Dr. Randall Ross (GWERD)
and Dr. Milovan Beljin (CSS) provided technical review comments to RPM Patricia
Bowlin on the Final Groundwater Modeling Report, McCormick and Baxter Superfund
Site, Stockton, California.The groundwater model for the McCormackand Baxter
Superfund is relatively simple and due to the lack of data, it is not rigorously calibrated.
The"telescopic"approach with the regional and local scale models is reasonable.
The horizontal and vertical discretization of the model domain is sufficiently fine
considering the available data and the purpose of the model. MODFLOW and MT3DMS
are the appropriate codes for the processes being simulated. The steady-state flow
conditions are acceptable considering the lack of data for a transient simulation.
Some of the model assumptions are not well explained in the Report, especially the
boundary conditions. Considering the objectives of the model, the model can serve as
a useful management tool. The model deficiencies were recognized in the Report and
should be addressed in the future model updates.
Technical Assistance Region IX: On December 10,2015, Dr. Randall Ross (GWERD) and
Dr. Milovan Beljin (CSS) provided technical review comments to RPM Bonnie Arthur
on the Memorandum titled Frontier Fertilizer Groundwater Model Capture Zone
and Alternative Analysis, prepared by CH2M HILL, dated November 11,2015, for the
Frontier Fertilizer Superfund Site, Davis, California.The existing groundwater model
for the Site was used to evaluate the current extraction system. It was determined
that the current extraction system does not hydraulically contain the northern portion
of the target zone (volume) and the southern portion is only partially contained. The
report concludes that all three proposed modifications to the extraction system would
capture the bulk of the target volume. Because each alternative capture zone differs,
other factors have to be considered (e.g., the total extraction rates, the flushing rates,
etc.). Relying on a single well pumping rate increase seems to be the least attractive
option. Additionally, considering the uncertainties regarding the pumping rates of
new well installations, it appears that the most appropriate option is a combination
of an existing A-1 zone well and five new S-2 zone wells (one in the neighborhood).
Specific questions considered in this review are whether the assumptions are valid
and whether the report conclusions are reasonable. Considering the objectives of the
project, the existing groundwater model can serve as a useful management tool. The
use of particle tracking to evaluate capture zones as described in the Methodology
section is an acceptable approach.
Technical Assistance Region IX: On December 10,2015, Mr. Steven Acree (GWERD),
Dr. Robert Ford (LRPCD), and Dr. Barbara Butler (LRPCD), provided technical review
comments to RPM David Seter on the Background Groundwater Quality Assessment-
Revision 2,Yerington Mine Site,Yerington, Nevada. The document provides estimates
of the potential extent of mine-impacted groundwater using multiple lines of
evidence. In general, the use of these multiple lines of evidence and multiple analytes/
measures appears to be robust and appropriate given the complexity of this site. It is
-------
noted that these lines of evidence generally provide similar outcomes which increases
confidence in the approach. Spatial locations, sulfur isotopes and vertical hydraulic
gradients were used as the basis to propose twenty monitor wells for inclusion in a
chemical dataset for evaluation of concentration ranges representative of background
water sources. Vertical hydraulic gradients measured during the current monitoring
program reflect recent conditions and may not be representative of historical
conditions for which hydrologic data are not available. It is recommended that the
alternate 95/95 upper tolerance limits (UTL) calculated using the Group 3 datasets be
applied to evaluate the extent of impacted groundwater. It is also recommended that
the extent of mine-impacted groundwater be estimated for all zones.
Technical Assistance Region III: On December 15,2015, Dr. Daniel Pope (CSS), under
the direction of Dr. David Burden (GWERD), provided a technical review of the site
information for the East Mount Zion Landfill located in Springettsbury Township,
Pennsylvania, to RPM Mitch Cron.The manganese plume(s) boundaries, three-
dimensional configuration, and behavior, are poorly understood, due to limited
monitoring data, and complex Site conditions. Therefore, it was concluded that it
is problematic, with the existing data, to make an accurate assessment of whether
groundwater manganese concentrations are likely to meet remediation standards in
a reasonable timeframe, based on the MNA remedy in place. More characterization
would likely be very helpful for improving predictions of future plume behavior;
however, given the Site complexities, uncertainty would still be high for predicting
future plume behavior. Also, it is recommended that the proposed additional
monitoring wells be installed along the longitudinal axis of the manganese plume.
EPA technical guidance for MNA, including EPA 1999, and EPA 2007, should be used to
guide future characterization and monitoring. EPA 2007 provides detailed technical
guidance on site characterization and monitoring for inorganic contaminants, and on
statistical and modeling approaches to analyzing the data.
Technical Assistance Region V: On December 15,2015, Dr. Daniel Pope (CSS), under the
direction of Dr. David Burden (GWERD), provided a technical review of site documents
to evaluate a proposed shut down of Purge Well 4 (PW4) at the Chem Central
Superfund Site (Site) in Wyoming, Michigan. There are numerous contaminants in Site
groundwater. Remedial approaches for the Site include the Groundwater Management
System (GWMS), and natural attenuation of groundwater contaminants. In general,
the proposed approach PW-4 shutdown and monitoring approach discussed in the
Memo is reasonable. However, the Site is complex, with varying hydrogeological
conditions, biological processes, contaminants, and remedial activities.The Memo
mentions intrinsic (natural) attenuation capacity, and indicates that such attenuation is
contributing to the apparent decrease in contaminant concentrations along the plume.
While natural attenuation is doubtless contributing to contaminant concentration
decreases along the plume, the effect of natural attenuation processes would be
expected to vary significantly depending on the particular mix of contaminants,
geochemistry, and contaminant concentrations found along the plume. The GWMS is a
major factor in determining the mix of contaminants, geochemistry, and contaminant
concentrations found along the plume, as well as groundwater and contaminant flow
paths. As the Memo discussion indicates, changes in the GWMS can cause dramatic
changes in the contaminants present, and therefore would have strong potential for
changing the effects and efficacy of natural attenuation processes. Therefore, any
changes in the GWMS should be approached with caution.
31
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Technical Assistance Region II: On January 7,2016, Dr. Daniel Pope (CSS), under the
direction of Dr. David Burden (GWERD), provided technical review comments to
RPM Diane Salkie on the enhanced bioremediation pilot study plan for the Caldwell
Trucking Superfund Site (Site) located in Fairfield, New Jersey. The proposed Pilot
Testing Study includes extraction of groundwater from injection and monitoring wells
in the proposed treatment zone, addition of sodium lactate and other materials to
this extracted groundwater, and re-injection of the amended groundwater into the
bioremediation treatment zone. It appears from the groundwater geochemistry in
the proposed treatment zone that bioremediation of dissolved TCE in the treatment
zone could be usefully enhanced by the proposed biostimulation, and possibly by
bioaugmentation.The Performance Goals and Objectives for the Pilot Testing Study in
the treatment zone and downgradient of the treatment zone seem feasible. However,
due to reagent distribution problems in such difficult hydrogeological conditions it is
likely that treatment will be significantly non-uniform throughout the treatment zone
and downgradient. In general, use of pump-assisted injection can help in increasing
the aquifer uptake of reagents and the distribution range of reagents. However, in the
proposed treatment zone geology it is difficult to predict how groundwater flow paths
and contaminant mobility might be affected.
Technical Assistance Region IV: On January 11,2016, Dr. Scott Huling (GWERD)
provided a technical review of site documents (a memo report and a response memo).
It was reported in the memo report that"the system has significantly decreased the
mobile NAPL thickness and product thickness has achieved asymptotic conditions." It
was noted that during the time period when the last light non-aqueous phase liquids
(LNAPL) interface measurements were made, zone 2/3 LNAPL recovery wells were
in operation. LNAPL thicknesses in wells can rebound resulting in a new equilibrium
of product thickness after extraction wells are turned off. Consequently, the LNAPL
thickness measured in zone 1 -3 wells will likely increase upon the termination of
NAPL recovery operations. It was unclear to what extent the volume of NAPL recovery
had diminished, and whether other factors are involved in the decline of product
thicknesses in wells undergoing active groundwater pumping. It was recommended to
continue the OU-1 /Phase 1 (MPE System) for an additional operation period, that the
overall design of the NAPL recovery system be re-evaluated to assess product recovery
and possible enhancement, that product thicknesses be re-measured, and that future
decisions involving the transition from LNAPL recovery to ISCO deployment take
into consideration the updated LNAPL product thicknesses and projections in LNAPL
volume.
Technical Assistance Region IX: On January 12, 2016, Mr. Steven Acree (GWERD) and Dr.
Robert Ford (LRPCD) provided technical review comments to RPM David Seter on the
Draft Initial Screening of Remedial Alternatives, Yerington Mine Site,Yerington, Nevada.
The document states that the plume of mine-impacted groundwater is stable based on
evaluations of changes in the estimated volume of contaminated groundwater, sulfate/
uranium masses, and chemical center of mass through time. It is recommended that
this assessment be supplemented by evaluations of well-specific temporal trends in
the concentrations of site-related chemicals. The document uses a simple analytical
approach to support the contention that groundwater restoration is impracticable.
It is recommended that more detailed analyses be considered to provide additional
perspective. Note that the general response actions for off-site groundwater did not
include containment. It is recommended that this response action be reconsidered
following a more detailed assessment of plume stability. Tables in the document,
32
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which describe response actions, technologies, and assessments of effectiveness and
implementability, may serve as an initial basis for discussions in the feasibility study.
However, much additional discussion, and the results of supporting analyses will be
needed to fully support remedial decisions and the technical opinions expressed in this
document.
Technical Assistance Region V: On January 14,2016, Dr. Daniel Pope (CSS), under the
direction of Dr. David Burden (GWERD), provided technical review comments to RPM
Kyle Rogers on the Proposed Pilot Test for the Kenosha Engine Plant Site, Kenosha,
Wisconsin. The review is a general assessment of the extent and magnitude of the
scopes of work (SOW) for proposed pilot tests of enhanced reductive dechlorination
(ERD) and in situ chemical oxidation (ISCO) at the Site.The conclusions that field pilot
studies are needed for design of a full-scale implementation of ISCO and ERD, and that
bioaugmentation would be appropriate during the ERD pilot study, are appropriate.
In general, the Work Plan and the SOWs appear to be well thought out, thorough, and
detailed. The monitoring plans are appropriate, though it would be useful to consider
some flexibility in the dates of sampling events so sampling dates could be adjusted
if needed. However, the extent and magnitude of the pilot study could probably be
reduced without significantly reducing the usefulness of the resulting data for design
of the full-scale effort. Such an approach could reduce the investment of resources
necessary to determine if ERD is a viable candidate for full-scale remediation at the
Site.The ISCO pilot study design is not specifically considered in these comments. The
general design of the ISCO pilot study in terms of injection points and monitoring
points is similar to that of the ERD pilot study, so it appears there may be potential to
reduce the scope of the ISCO pilot study as well.
Technical Assistance Region IX: On January 26,2016, Dr. Eva Davis (GWERD), provided
technical review comments to RPM Carolyn D'Almedia on the Draft Addendum #2
to the Remedial Design and Remedial Action Work Plan for Operable Unit 2 for the
Revised Groundwater Remedy for Site ST012 at the Former Williams Air Force Base in
Mesa, Arizona. In theory it would appear that the Addendum is an update of Section
3.5 of the Final Remedial Design/Remedial Action Work Plan (RD/RAWP). Comparing
Section 3.5 of the Final RD/RAWP to Addendum #2, it appears that prior plans for
active EBR have been scaled back. In addition, the operation of a recirculation system,
which had been expected to operate for 1.5 to 3 years during EBR, was reduced and
recirculation will be employed only "if necessary". None of these changes from the
approved Final RD/RAWP are explained in the Addendum, none of them would appear
to be justified based on the small decrease in the modeled area believed to contain
LNAPL, and all of them - especially when taken together - would appear to severely
reduce the amount of enhancement to natural biodegradation that is being planned.
Addendum #2 presents a confusing array of estimates of LNAPL mass in the subsurface.
Pre-SEE LNAPL contours were developed for the site using a three dimensional model
which interpolated a surface between the contours. Interpolated contours from a
three dimensional model should not be substituted for actual field characterization of
the extent of LNAPL in the soil and dissolved in the groundwater. This characterization
must be completed before finalizing plans for the EBR, to ensure that all areas of
remaining contamination are treated. The design of the EBR system in Addendum #2 is
only conceptual in nature. A complete design must include additional information.
33
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Technical Assistance Region IX: On February 1,2016, Mr. Steven Acree (GWERD),
Dr. Robert Ford (LRPCD), and Dr. Barbara Butler (LRPCD), provided technical review
comments to RPM David Seter on the Background Groundwater Quality Assessment-
Revision 2-Addendum,Yerington Mine Site,Yerington, Nevada. As a part of continuing
technical support, the extent of mine-impacted groundwater north of the mine site
has been estimated using available data, including lines of evidence presented in the
Background Groundwater Quality Assessment-Revision 2. The review indicates that
the extent of mine-impacted groundwater may be somewhat broader northwest and
northeast of the site than displayed in Figure 7-1 of the referenced report.
Technical Assistance Region IV: On February 8,2016, Dr. Scott Huling (GWERD)
provided a technical review of site documents for the Sonford Products Site
(Flowood, Mississippi) to RPM Neema Atashi. Dr. Huling reported that the solubility of
pentachlorophenol (PCP) is pH dependent and correlated well with results presented
in the in situ chemical oxidation (ISCO) treatability study report. A significant change in
the PCP concentration occurred as a result of ISCO base activation conditions, and pH
dependency of PCP chemical oxidation under base activated conditions was projected.
This concept was extended to field conditions where the pH may remain basic for
an extended period of time resulting in the potential for enhanced PCP solubility
and transport in groundwater. It was recommended that enhanced transport of PCP
in groundwater be evaluated and that a contingency plan be prepared, if needed.
Elevated concentrations of persulfate were present in the soil slurry reactors when ISCO
testing terminated. Unless the persulfate was neutralized, the oxidant residual would
likely impact water quality samples yielding false negative results. Results suggested
that soil samples used in the study were not representative of the LNAPL conditions
in the field. Since PCP has partitioned into the LNAPL, the oxidant dosage required to
achieve PCP mass reduction may have been underestimated. It was recommended
that a round of post-pumping LNAPL thicknesses be measured in the product recovery
wells to assess rebound. Anticipating that the updated LNAPL thickness measurements
reveal significant LNAPL volume, it was recommended that LNAPL recovery be
continued prior to the deployment of ISCO activities.
Technical Assistance Region IV: On February 10, 2016, Dr. Eva Davis (GWERD), provided
technical review comments to RPM Julie Corkran on the Treatability Study (TS) Report
for the C-400 Interim Remedial Action Phase lib Steam Injection Treatability Study
at Paducah Gaseous Diffusion Plant, Paducah, Kentucky dated December 2015. In
general, the Report accurately documents the results of the field scale steam injection
that was carried out from April to June, 2015. However, there are concerns about the
modeling that was performed, the conceptual design of the full scale steam injection
system, and the estimated costs. Based on discussion in theTS Report, it appears that
only one three dimensional (3D) simulation of the full scale system was performed. If
this is the case, it is not clear how the design can be confirmed to be optimum.The
3D modeling effort reported also does not include a sensitivity analysis. It should
be explained in detail why it is believed that extending the treatment area to the
south will maximize contaminant removal, and what in the soil boring logs indicates
that the southernmost extent of the suspected treatment area is near Tennessee
Avenue. If additional contamination outside of the originally proposed treatment
area was found during the installation of wells for theTS, or if it is commonly found
that past delineations of contaminant extent were faulty, then perhaps additional
characterization should be undertaken surrounding the entire treatment area to
determine the appropriate treatment area.
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Technical Assistance Region III: On February 10,2016, Dr. Scott Huling (GWERD)
provided technical review comments to RPM Susanne Haug on the January 2016
60% Conceptual Design for In-Situ Chemical Oxidation of Groundwater at the SE Area
Operable Unit 3A 11, and 6, Letterkenny Army Depot, Chambersburg, Pennsylvania.
It is clear that many of the oxidant transport issues associated with the proposed
in-situ chemical oxidation (ISCO) remedy have been recognized in the 60% design
report.There remains some uncertainty in the approach used to assess oxidant fate
and transport and in the projections of oxidant concentrations that may emerge in
Rowe Run. It was reported that the objective is to keep the permanganate (Mn04~)
concentration from exceeding 0.5 -1 mg/L because there are unacceptable effects to
algae at potassium permanganate (KMn04) concentrations as low as 0.5 mg/L, and
to crustaceans and fish at concentrations less than 1 mg/L. Regulatory clarification
is needed as to whether these impacts are documented to occur at 0.5-1 mg/L,
or whether these effects occur below these levels, and whether there is an EPA
established regulatory threshold value for Mn04~ that must be met. In general, it is
recommended that either the impact of the Mn04~ concentrations are better defined,
and/or that EPA regulatory requirements for Mn04~ in aquatic systems be determined
that reflect ecotoxicological impacts. Once the Mn04~ objective is established,
performance goals in upgradient locations (i.e., monitoring wells) can be developed.
Technical Assistance Region VI: On February 16,2016, Dr. Milovan Beljin (CSS) and Dr.
Randall Ross (GWERD), provided technical review comments to RPM Richard Mayer
on the Measures Work Plan (WP) for Chromium Plume Control, Los Alamos National
Laboratory, Los Alamos County, New Mexico. Groundwater modeling discussions and
results presented in the WP appendix include numerous uncertainties, which make
it unclear whether the objectives will be fully or partially achieved, especially within
the projected period of three years. Despite these limitations, there are no compelling
reasons why the proposed capture system should not be initiated. Data collected
during the operation of the extraction and injection system will be useful to refine the
current groundwater model. It is recommended that samples be acquired from the
injection wells prior to initiation of injection to enhance the general understanding of
the chromium plume. Any new wells installed to delineate the downgradient extent
of the chromium plume should be monitored regularly to evaluate the effectiveness
of hydraulic capture. The need for regularly scheduled rehabilitation of injection (and
extraction) wells should be assumed. Water levels measured in extraction wells should
not be used to evaluate capture or construct water level elevation maps.
Technical Assistance Region II: On February 22,2016, Dr. Eva Davis (GWERD), provided
technical review comments to RPM John DiMartino on the Diaz Chemical Corporation
Superfund Site Operable Unit 2 Draft Design Analysis Report and Draft Performance
of Work Statement for In Situ Thermal Remediation, dated December 2015. Careful
consideration must be given to selecting the area in which the Phase 1 or pilot
study remediation will be carried out. A location surrounded on all sides by highly
contaminated soils - as is currently proposed - is not recommended for the first phase
of treatment. After reviewing the soils data, it is recommended the first phase of
treatment be carried out in an area in the northwest corner of the proposed treatment
area. Lengthy specifications containing minute details sometimes obscure the very
important information which is very specific to this project. Critical information specific
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to this project must be included in the contract document. It should be kept in mind
that the thermal vendors are small businesses that specialize in thermal remediation
work. The contract with the thermal vendor should be limited as much as possible
to that necessary for thermal remediation, and a separate contract with a general
contractor should be used for some of the ancillary work.
Technical Assistance Region II: On February 26,2016, Dr. Bruce Pivetz (CSS), under the
direction of Mr. Steven Acree (GWERD), provided technical review comments to RPM
Clifford Ng on the 2014 Annual Groundwater Report and 2014/2015 Quarterly Reports,
DuPont/Chemours Pompton Lakes Works, Pompton Lakes, New Jersey. This review did
not reveal any obvious issues regarding the operation of the groundwater extraction
and treatment system. The addition of piezometers in 2014 provides a more realistic
potentiometric surface depiction, as the potentiometric surface maps no longer have
to rely on groundwater elevations made in the extraction wells adjacent to these
piezometers. Even though the November 2014 and later potentiometric surface maps
do not show as great of an impact of the extraction wells as depicted on earlier maps,
there appears to be a significant degree of hydraulic control near the southern plant
boundary. The effects of the system are particularly evident in the shallow zone where
the extraction/infiltration system has the greatest impact.
Technical Assistance Region II: On March 5,2016, Dr. Richard Wilkin (GWERD) provided
technical review comments to RPM Ray Klimcsak on the "Remedial Investigation (Rl)
Report for United States Avenue Burn Site Gibbsboro, Camden County, New Jersey,
Administrative Order Index No. II CERCLA-02-99-2035." It is noted in the Rl that arsenic
and lead concentrations in soil were determined using a handheld XRF analyzer.
There is a well-known interference issue when measuring the concentration of these
elements using XRF techniques. It is important to point out the interference issue in
the Rl and state how it was handled. It is suggested that in addition to the analysis
of Kd values, as presented in the Rl, additional discussion be added regarding the
solution chemistry apparent in the regions where lead and arsenic are present to
elucidate the most important controls on groundwater concentrations. It is stated
that arsenic and lead are essentially immobile in groundwater.The site data do largely
support that regions with elevated lead and arsenic concentrations are restricted
spatially and that groundwater migration is slow. It is recommended that some effort
go into understanding the processes which limit the migration of lead and arsenic,
i.e., the natural attenuation pathways. It is noted that high concentrations of iron
and manganese in some locations are not likely the result of natural processes. The
discussion goes on to note that the higher concentrations of iron and manganese
in these restricted locations are a consequence of somewhat reducing conditions.
Further development of this idea is suggested. It is also recommended that plume
maps be developed for some of the key groundwater contaminants, such as arsenic,
lead, and benzene.
Technical Assistance Region V: On March 9, 2016, Dr. Richard Wilkin (GWERD) provided
technical review comments to RPM Greg Rudloff on the "Area 1 ISCR Pilot Study
Summary Report, Eckles Road Site, Livonia, Michigan." The 2015 pilot study follows
up on a laboratory treatability study and previous field pilot studies in 2010 and
2013. It is anticipated that a full-scale application of the dithionite/sulfide treatment
will be conducted at the site. In addition, a downgradient permeable reactive barrier
is being considered as a polishing step for the treatment of hexavalent chromium
and nickel. Electrical Conductivity (EC) borings were appropriately used, and the
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EC response was very good at most locations. It is recommended that the EC probe
be checked with standard electrical conductivity standards. It was noted that the
bromide tracer test failed due to high concentrations of other anions. It may be
possible to use other techniques, such as flow injection analysis, for bromide analysis
in subsequent implementations. For example, consider using flow injection analysis
over ion chromatography for bromide quantitation. A number of factors are introduced
regarding the performance of ZVI and how the in-situ treatment could potentially
interact with ZVI. However, other key groundwater parameters that influence ZVI
behavior are not discussed. Generally, the proposed in-situ reduction approach is
favorable for coupling with ZVI treatment because excess oxidants, which have a
negative impact on ZVI performance and longevity, are consumed. It is suggested that
before selecting a buffer distance a more complete evaluation be performed of the
likely groundwater composition that will potentially interact with ZVI, with subsequent
consideration of potential changes in reactivity and hydraulic conductivity in a ZVI
system.
Technical Assistance NRMRL/WSWRD: On February 8,2016, Dr. Michelle Simon, NRMRL/
Water Supply Water Resources Division, Urban Watershed Branch Chief, requested
technical support from Dr. Junqi Huang (GWERD) to provide a technical review of
Storm Water Management Model Reference Manual Volume III - Water Quality. It
is reported in the manual that a complete user guide for utilizing a storm water
management simulator is given. Besides the inheritance for all, a very useful and
powerful feature of the previous version, the model enhanced the LID (Low Impact
Development) package that is used to model the water quality processes associated
with LID practices. It was concluded that the reference manual would be quite helpful
for the practitioners working in the storm water management area. Discussions about
the model theory base, model parameters estimation, model algorithms, model inputs
and output were provided. No major revisions were suggested.
Technical Assistance Region I: On March 18,2016, Dr. Eva Davis (GWERD) provided
technical review comments to RPM Jim Brown on the Electrical Resistance Heating
Remedial Action Work Plan and Project Operations Plan for the South Municipal Well
Superfund Site located in Peterborough, New Hampshire, dated February 2016. Much
of this document pertains to the construction of the in situ thermal remediation
system, which was completed in 2015. Comments focus on the plans for operation
and monitoring of the system. A schedule including all milestones for the operational
phase of the thermal remediation should be provided in the Work Plan. This schedule
will allow evaluation of the progress of the remediation relative to the design, and will
help to ensure that sampling is performed on schedule and that the agencies receive
the data in a timely manner. Also, the Work Plan should include a detailed voltage
monitoring plan describing special precautions that will be taken for the areas which
will remain accessible to the public throughout the remediation.The Health and Safety
Plan discusses action levels for volatile organic compounds (VOCs) in the breathing
zone. The action levels used here should be consistent with those used in the fugitive
emissions monitoring plan. Also, it is recommended that the Work Plan include
additional details of how the developed framework should be applied at this site.
Technical Assistance Region VI: On March 28,2016, Dr. Scott Huling (GWERD) provided
technical review comments to RPM Stephen Tzhone on "Arkwood, Inc., Superfund
Site EPA Comments on Draft Supplemental Groundwater Tracing Summary Report
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dated March 2015 McKesson Corporation Response-To-Comments". Previously,
water was continuously injected near the sinkhole area of the contaminated site
over a 7 year period, and ceased in 2012. The objective of the injected water was
to enhance groundwater remediation. Historically, and currently, the hydraulic and
contaminant transport conceptual model proposed in the Report indicate that all of
the contaminated groundwater leaving the site is captured at the New Cricket Spring
(NCS). However, based on the results of a critical analysis involving a simplified water
budget for the site, the proposed conceptual model and the assumption that capture
has been achieved do not appear to be valid. In various reports and correspondence
regarding tracer tests conducted between the sinkhole and NCS, several mechanisms
and processes are proposed that may be responsible for the lack of dye recovery.
However, the possibility that NCS does not achieve complete capture of the tracer in
the groundwater leaving the site is not acknowledged. The record of decision for the
Arkwood site was issued in 1991 at a time when non-aqueous phase liquids (NAPL)
sites were poorly understood and site characterization and remedial activities were
generally lacking to address sites contaminated with NAPLs. Although excavation of
contaminated soil was part of the soil remedy at the Arkwood site, it is probable that
NAPL migrated beyond the depth of excavation prior to excavation activities. The dye
tracer test conducted in 1991, and water table elevations suggest that a groundwater
divide likely exists at the site and that there are at least two directions of groundwater
contaminant transport. It is recommended that additional groundwater monitoring
wells are placed in appropriate locations and screened over appropriate intervals to
assess the fate and transport of contaminants in the groundwater leaving the site.
Technical Assistance Region I: On April 18,2016, Dr. Milovan Beljin (CSS), Dr. Randall
Ross and Mr. Steven Acree (GWERD) provided technical review comments to RPM Carol
Keating on the Shepley's Hill Groundwater Model Revision Summary and Preliminary
Results Memorandum, Fort Devens Site, MA. The current groundwater flow model
represents a significant improvement over previous modeling efforts. However, the
groundwater flow model appears to lack the necessary accuracy to satisfy the stated
objective of evaluating the performance of the existing groundwater capture system.
Generally, it is desirable to have an even distribution of positive and negative residual
values that plot along a diagonal line. However, it is not desirable for the residuals
to cluster. The clustering of residuals may be an indication of a systematic bias in the
model. The consequence of the bias is that the simulated hydraulic gradient is lower
than the actual gradient. The magnitude and sometimes the direction of simulated
hydraulic gradients appear to differ from observed gradients in several locations. This is
reflected in the maps of residuals produced by the model during various stress periods
and limits the reliability of the model for the purpose of evaluating remediation
system performance. Once the residual bias issues are addressed and the model better
simulates observed conditions, additional particle tracking should be performed
using a higher vertical and horizontal density of particles per layer to better define the
capture zone.
Technical Assistance Region III: On April 29, 2016, Dr. Dominic DiGiulio (CSS), under the
direction of Dr. David Burden (GWERD), provided technical review comments to RPM
Debra Rossi on the response to comments of the Bioventing System at the Maryland
Sand, Gravel, and Stone Site located in Elkton, MD. Pressure or vacuum checks on
above ground fittings used for soil-gas sampling should be considered. There should
also be periodic leak tests to verify the absence of leakage down boreholes during soil-
gas sampling. Consideration should be given for the use of water table suppression
combined with dual vapor extraction and air sparging in the event of failure to meet
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remedial objectives associated with substrate addition. They should also consider the
use of direct-push soil-gas sampling techniques to enable vertical profiling of volatile
organic compound, oxygen, and carbon dioxide concentrations during bioventing
system shut down. Using a tracer during respiration testing to quantify the effect of
dispersion on respiration testing results is also recommended. Finally, they should
consider the use of a relative-humidity filter for operation of the photoionization
detector and submittal of results of checks with calibration standards in reports
submitted to EPA.
Technical Assistance Region II: On April 29,2016, Dr. Scott Huling (GWERD) provided
technical review comments to RPM Denise Zeno on the document entitled,"Draft
Solid Waste Management Unit 20 Pilot Study Sampling and Analysis Plan Atlantic
Fleet Weapons Training Area - Vieques,"Vieques, Puerto Rico. It was reported that
the hollow-stem auger drilling method would be used in the unconsolidated soil/
weathered bedrock and air rotary drilling method would be used in the saprolite or
fractured bedrock to the appropriate depth. It appears that groundwater samples will
be analyzed, and that the aquifer samples will be used in the NOD tests. Currently, it
is assumed that the entire interval is contaminated, which may be correct. However, it
may be possible that only discrete intervals are contaminated and that identification of
these intervals could be used to refine the conceptual site model. It is recommended
that the aquifer material brought to the surface during the installation of the injection
and monitoring wells be sampled and analyzed over discrete intervals for CVOCs.
This data and information can provide more definitive information, and the priority of
ISCO and treatment performance monitoring activities could be focused over smaller
intervals, resulting in significant cost savings. It was reported that a preliminary tracer
and ISCO pilot study would be conducted in IW-01. This information would then be
used to guide the remainder of the pilot study. It is also recommended that the report
be revised with discussion of the porosity associated with the various media reported
in the figures where oxidant may be injected including saprolite, bedrock, saprock, and
granodiorite.
Technical Assistance Region I: On May 4,2016, Dr. Eva Davis (GWERD) provided
technical review comments to RPM Cheryl Sprague on the Phase 1 Thermal
Remediation Action/Demonstration of Compliance Report for the Beede Waste Oil
Superfund Site located in Plaistow, New Hampshire. In general, the Report documents
the construction, operation, and achievement of the Performance Standards for this
portion of the site-wide remedy. However, additional details on operational problems
that were encountered during the operations and their solutions would help to make
this report a stand-alone document that details the Phase 1 remedy. Also, the lessons
learned during the Phase 1 implementation should be documented in this report.
The difficulties encountered during the Phase I implementation, which included
nonaqueous phase liquid (NAPL) separation, sludge formation and separation,
and meeting discharge criteria for arsenic and bromate, were all successfully met.
The solutions to the problems encountered should be documented in detail to be
incorporated into the Phase II design and operational strategy, as it is likely that many
of the same conditions will be encountered in the Phase II treatment area. As already
some changes in key technical personnel have occurred, it is prudent to document
in detail the knowledge gained during Phase I before more changes occur and
information is lost or forgotten.
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Technical Assistance Region II: On May 16,2016, Dr. Richard Wilkin (GWERD) provided
technical review comments to RPM Richard Ho on the"HCAA Bench-scale Testing
Report, Quanta Resources Corporation Superfund Site, Operable Unit 1, Edgewater,
NJ" dated February 2016. The report presents and reviews results of extensive field and
lab studies conducted to meet requirements in the Record of Decision (ROD) which
dictates that leachability of arsenic be reduced by 90% in subsurface soils and aquifer
solids within the high-concentration arsenic area (HCAA). Previous studies concluded
that enhanced sulfate reduction could be an effective approach for stabilizing arsenic
in the solid phase, and evaluations were undertaken to identify specific chemical
amendments and dosing requirements to meet the remedial objective of 90% or
greater reduction of arsenic leachability Based on geochemical modeling and Phase 1
laboratory microcosm tests, it was determined that a combination of lactate and iron
injections could be used to meet the ROD criterion. However, during scaled-up Phase
2 testing with approximately 4-times the soil mass of Phase 1 tests, it was discovered
that after 6 weeks of aging, arsenic concentrations in native sand and fill microcosms
were increasing rather than decreasing as expected. Attempts were made to redose
the microcosms to reverse the arsenic release, but the test results were considered to
be inadequate for reaching the objectives specified in the ROD.
Technical Assistance Region I: On May 16,2016, Dr. Bruce Pivetz (CSS), under the
direction of Mr. Steven Acree (GWERD), provided technical review comments to
RPM Karen Lumino on the compliance monitoring reports (CMRs) for the Pine Street
Canal Site, Burlington, VT, discussing results of monitoring activities performed
during Fall 2014, Spring 2015, and Fall 2015, were reviewed. The focus of the review
was to evaluate whether or not the data in the CMRs support a conclusion that the
vertical barrier (VB) is performing as intended. In general, the remedial strategy
envisioned with the installation of the VB appears to be relatively effective, and the
VB is performing as intended. The modification (i.e., diversion) of contaminated
groundwater flow due to the VB may be expected to lead to some (ideally, temporary)
increases in contaminant concentrations as the groundwater flows around and over
the VB. The trends in dissolved benzene and naphthalene that have been observed
in some wells have been adequately explained, and relates them to the presumed/
desired impact of the VB. These trends need to be interpreted in view of the remedial
strategy behind the installation of the VB. It is recommended that monitoring be
continued, especially at the southern end of the VB. If decreasing trends in dissolved
contaminants downgradient of the VB are not observed over the next few compliance
monitoring periods, the groundwater flow conditions at the southern end of the VB
may need to be re-examined.
Technical Assistance Region I: On June 22, 2016, Dr. Scott Huling (GWERD) provided
technical review comments to Rodene Lamkin, Massachusetts Department of
Environmental Protection, on the "Draft Phase III Remedial Action Plan, General
Chemical Corporation, 133-135 Leland Street, Framingham, Massachusetts."The use
of persulfate was proposed for in-situ chemical oxidation applications.Treatability
studies will be needed, if not already conducted, to better assess the overall feasibility
of this technology. Also, the impact of the residual from using sodium persulfate,
should be evaluated prior to the use of this oxidant at each of the areas of concern.
Specifically, the sulfate residual will elute from the injection zone in the groundwater
and may impact downgradient areas. Additionally, the use of permanganate ISCO,
in conjunction with bioremediation should be considered further. For example,
under some contaminant conditions, some CVOCs could be oxidized by Mn04", and
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subsequently followed by biodegradation to target compounds such as 1,4-dioxane.
A similar approach was proposed using persulfate. A potential advantage of this
approach is that the Mn04~ residuals are generally immobile and are projected to have
less impact than S042- residuals on downgradient areas.
Technical Assistance Region VII: On June 27,2016, Dr. Eva Davis provided technical
review comments to RPM David Wennerstrom on the Cleburn Street Well Superfund
Site Operable Unit 2 Draft Design Analysis Report for In-Situ Thermal Remediation,
and the Draft Performance Work Statement for In-Situ Thermal Remediation (ISTR). In
general, the PWS is well written and inclusive of the information required to effectively
bid the project. However, the objectives of the in situ thermal remediation are not
clearly defined. It should be determined whether the soil criteria or diminishing returns
criteria are used as the termination criteria. It does not appear that the area with
significant tetrachloroethene (PCE) concentrations in soil and/or groundwater has been
fully defined. One way to handle the lack of full delineation of the contaminated zone
above cleanup levels is to combine final characterization efforts with the installation
of the well field for the thermal remediation system. Additionally, data should be
provided on the concentrations of and distribution of the contaminants within the
thermal treatment area. To efficiently desorb and volatilize these contaminants, 88°C is
not an appropriate minimum temperature for the remediation. The target temperature
should be the boiling point of water, which will be dependent on the local pressure.
Technical Assistance Region II: On July 5,2016, Mr. Steven Acree (GWERD) provided
technical review comments to RPM Clifford Ng on the Implementation Work Plan-
Hydraulic Surcharging Pilot Study, Chemours Company, Pompton Lakes Works,
Pompton Lakes, NJ. In general, it appears that the revised plan reflects changes
proposed in response to previous reviews and adequately addresses previous
comments. It is recommended that the pilot study proceed.
Technical Assistance Region III: On July 8,2016, Dr. Richard Wilkin (GWERD) provided
technical review comments to RPM Debra Rossi on the "Assessment of Data to Suggest
Potential Source of Dissolved Manganese in the Upper Potomac Aquifer, Delaware
Sand and Gravel Superfund Site, New Castle, Delaware." Further evaluation of the
flow discrepancy is warranted; placement of additional wells may be necessary to
better interpret hydraulic and concentration gradients. As noted in the memo, the
degradation of organic compounds is likely the root cause in mobilizing manganese
in groundwater. Another approach involving evaluation of the major ion chemistry
and anions, was considered for identifying potential source areas. When future
samples are collected, consider determining major ions and cations; also consider
collecting bromide concentrations, as bromide can serve as a useful tracer. Preliminary
geochemical modeling was performed to evaluate potential controls on manganese
concentrations after it has been mobilized. This type of modeling could be useful
in making predictions about the behavior of Mn in regions downgradient from the
source.
Technical Assistance Region II: On July 21,2016, Dr. Bruce Pivetz (CSS), under the
direction of Mr. Steven Acree (GWERD), provided technical review comments to RPM
Clifford Ng on the Draft Onsite Groundwater Interim Remedial Measures (IRM) Design
Testing Work Plan, Chemours Pompton Lakes Works, Pompton Lakes, NJ. The work
plan is a concise description of design testing of in-situ chemical oxidation. The work
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plan appears to be well-written, accurate in technical aspects, and this review concurs
with the substantive aspects of the plan. It is recommended that the parameters and
calculations used to estimate the radius of influence be provided as a response to this
review, to aid in reviews of the design testing. It appears that the process monitoring
wells will not be able to collect samples individually from the unsaturated or saturated
zones, however, it is recommended that the rationale be provided for not monitoring
the individual injection zones. It is also recommended that additional soil samples be
collected from each zone, and from the treatment areas for the Soil Oxidant Demand
testing. It appears that preparation of additional oxidant solution within the mix tank
will be needed even as the oxidant solution is being injected. And it is recommended
that samples be taken from the mix tank at intervals throughout each day to verify the
oxidant concentrations that are being injected.
Technical Assistance Region I: On July 22, 2016, Dr. Eva Davis (GWERD) provided
technical review comments to the Massachusetts Department of Environmental
Protection on the "Draft Phase III Remedial Action Plan (RAP) for General Chemical
Corporation (GCC), located in Framingham, Massachusetts, dated February 15,
2016."The review focused on thermal remediation aspects of the RAP. According to
Frascari et al. (2015), aerobic cometabolism processes have not been widely used for
bioremediation of chlorinated volatile organic compounds (CVOCs). Frascari et al.
(2015) also report that when the growth substrate for aerobic cometabolism is injected
via air sparging (AS), a portion of the CVOCs will be stripped from the groundwater
by the air and discharged to the atmosphere rather than degraded. In order to avoid
discharge of the CVOCs to the atmosphere, soil vapor extraction (SVE) would need
to be incorporated into the design of the bioremediation system. Due to the very
high solubility of 1,4-dioxane in water, it may not be treated sufficiently by AS. The
proposed bioremediation may not be able to eliminate or mitigate the discharge of
contaminants to the aqueduct, the drainage ditch, and Course Brook, and thus may
not achieve a Temporary Solution. The water and VOC vapors generated by thermal
remediation would rapidly condense once outside of the heated zone, thus the
possibility of vapors impacting adjacent properties are minimal. This is in contrast to
a SVE/AS system, where VOC vapors would be carried with the injected air, and could
travel much greater distances.
Technical Assistance Region IV: On July 25, 2016, Dr. Scott Huling (GWERD) provided
technical review comments to RPM Michael Taylor, and William Osteen, Region 4
Superfund Division, on the "Draft Groundwater 100 Percent Optimized Groundwater
Design Report Rev 01, Picayune Wood Treating Site, Picayune, MS March 2016," and
related documents. There are multiple cases where recovery wells are located on the
exterior and adjacent to the containment cell. This may result in a condition where the
hydraulic gradient favors the transport of contaminants from inside the containment
cell to the exterior. It was recommended to consider an emplacement method of
oxidant delivery rather than the use of a recirculation system to deliver the oxidant. A
decision to use an oxidant recirculation system should be heavily scrutinized due to
the significant capital, and operation and maintenance costs that accrue with oxidant
recirculation systems. Design and operation of an oxidant recirculation system requires
the careful integration of the in-situ chemical oxidation operations, hydrogeology,
conceptual site model, and the above-ground treatment train. It was recommended
that this aspect of the remedial activities design and deployment be re-evaluated
before the design be considered further. It was also recommended that sodium or
potassium permanganate be selected as the oxidant to be injected and was based
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on several criteria including oxidant demand, treatment performance at bench scale,
uncertainties involving other oxidants, cost, persistence in the subsurface, water
chemistry, and delivery options.
Technical Assistance Region X: On August 2,2016, Dr. Richard Wilkin (GWERD)
provided technical review comments to RPM Jannine Jennings and Bernie Zavala,
Region 10, on the"Additional Groundwater Geochemistry Studies Phosphoric Acid
Plant Area, Simplot OU, Eastern Michaud Flats Superfund Site, Pocatello, Idaho" (dated
June 2016). In Section 4, it is recommended that the specific ion activity model be
included in the text. The results of mineral saturation state calculations are highly
dependent on the model used to estimate activity coefficients. Examination of the
modeling outputs indicates that some of the modeled groundwater compositions
had poor charge balance. It was noted that the inability to achieve stable readouts
of geochemical parameters during well purging caused an inaccurate assessment of
the geochemical stratigraphy in groundwater. It should be expected that instrument
drift will be encountered when pumping a stratified water column. It is clear from
the mineralogical testing and groundwater chemistry that pump fouling was caused
by precipitation of gypsum and/or a poorly crystalline aluminous iron phosphate
mineral.There may be the possibility that gypsum scale could be prevented by
adding EDTA to the wells. It is stated that gypsum saturation depends more on the pH
than sulfate activity. The pH of the groundwater was in all cases above the bisulfate/
sulfate boundary; therefore, in this pH range it would appear that gypsum solubility
is independent of pH. Also, it would seem that calcium concentrations are quite
important in determining the saturation state with respect to gypsum, more so than
pH.
Technical Assistance Region I: On August 11,2016, Dr. Eva Davis (GWERD) provided
technical review comments to Sherry Banks, OSC, Region 1, on the Evaluation of In
Situ Thermal Remediation for the Lonsdale Bleachery Site, Lincoln, Rhode Island.The
site is contaminated with a heavy fuel oil that has been classified as Bunker C fuel oil
from historical operations at the site. Due to the proximity of the site to the Blackstone
River, oil and/or an oily sheen is discharged to the River at times of low river flow.
The objective of the remedial activities that have been - or are to be - taken at this
site are to eliminate this oil and sheen discharge to the Blackstone River. Due to the
fact that the site is adjacent to a surface water body, separated from the River by an
historic retaining wall, steam enhanced extraction and electrical resistance heating
are not appropriate for the site. The oil contaminated Blackstone River sediments are
not amenable to thermal remediation of any type. There are uncertainties associated
with this proposed remediation that would affect the effectiveness of the remediation
and the costs. It is recommended that additional characterization be completed to
determine the aerial extent of the oil, and that short term groundwater pump tests
be conducted to obtain estimates of the hydraulic conductivity of the soils at the site.
It is also recommended that bench scale tests be conducted on the oil to determine
its viscosity as a function of temperature, the percent volatiles as a function of
temperature, and the treatment temperature and time required to remove enough
of the more volatile compounds to render the remaining oil free of sheen-causing
compounds.
Technical Assistance Region IV: On August 15,2016, Dr. Eva Davis (GWERD) provided
technical review comments to RPM Marcia O'Neal on the Supplemental LNAPL Work
Plan forT H Agriculture & Nutrition L.L.C. (THAN), located in Albany, Georgia, and dated
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July 2016. The Supplemental Work Plan describes proposed field work to fill data gaps
in the characterization of the site by obtaining additional Rapid Optical Screening Tool
(ROST) data to determine the extent of light non-aqueous phase liquid (LNAPL). The
proposed locations for additional ROST borings appear to be appropriate, however,
it is not clear that the work plan includes all of the step out locations that are likely to
be needed in order to fully define the extent of the contamination. In addition, more
step out locations may be needed depending on the results of some of the proposed
borings, and the work plan should allow for these borings to be completed. Also, the
ROST borings will be limited in depth to the weathered limestone, but it is not clear
that vertical contaminant migration is limited by the competent limestone bedrock.
Deeper borings are required to determine the vertical extent of contamination.
Technical Assistance Region VI: On August 17,2016, Dr. John T. Wilson (CSS), under the
direction of Dr. David Burden (GWERD), provided technical review comments to Noel
Bennett, RCRA Corrective Action on the Draft Second Five Year-Review - Volume 1, for
the Former England Air Force Base, Alexandria, LA. The former England Air Force Base
(AFB) is located a few miles west of Alexandria, Louisiana. Contamination from releases
of chlorinated solvents has impacted the underlying Red River Alluvial Aquifer. The
Five-Year Review covers 49 separate Solid Waste Management Units (SWMUs). Ten of
the SWMUs have achieved a status of No Further Action (NFA). Seven of the SWMUs
have been remediated, and the U.S. Air Force is in the process of applying for a status
of NFA for these sites. At 32 SWMUs, risk associated with the remaining contamination
is managed through Land Use Controls administered by the U.S. Air Force. This review
focused on two of the SWMUs with groundwater contamination where monitored
natural attenuation (MNA) is part of the remedy. The interpretations of site data
and conclusions provided in the Five-Year Review are technically sound and are in
conformance with the expectations for monitored natural attenuation as provided by
U.S. EPA. It is recommended that the U.S. Air Force apply an approach developed by the
U.S. EPA Office of Research and Development to evaluate the performance of MNA as a
remedy. The approach should be applied in this review cycle and in subsequent review
cycles. It is also recommended that a date be established when SWMU 41 is required to
attain the cleanup goals.
Technical Assistance Region VI: On August 25,2016, Dr. Scott Huling (GWERD) provided
technical review comments to RPM Stephen Tzhone on the "Fourth Five Year Review
Report for the Arkwood, Inc., Superfund Site, Boone County, AR (August 15,2016)."
Based on the technical review of the 4th Five Year Review (FYR), and several other site-
related documents, there are two technical issues that impact long term protectiveness
and the recommended actions in the 4th FYR regarding the groundwater remedy. The
first issue is whether or not New Cricket Spring (NCS) captures all the contaminated
groundwater on the West side of the site. The second issue is whether contaminated
groundwater is discharged along the North and East sides of the site. To summarize,
strong evidence exists that contaminated groundwater bypasses NCS, yet there
are no downgradient or side-gradient groundwater monitoring wells to validate
the assumption proposed by the responsible parties that NCS achieves full capture
of the PCP contaminated groundwater. There is strong evidence to support that
contaminated groundwater discharges from the North and East sides of the site.
Yet there are no downgradient or side-gradient groundwater monitoring wells to
validate the assumption proposed by the responsible parties that this groundwater is
eventually captured by NCS. Given these two major data gaps, it is doubtful that the
groundwater remedy is protective.
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Technical Assistance Region IX: On September 6,2016, Dr. Richard Wilkin (GWERD)
provided technical review comments to Superfund Project Manager Holly Hadlock
on the"Hexavalent Chromium Summary Report for the Laboratory for Energy-
related Health Research/Old Campus Landfill Superfund Site University of California,
Davis" dated July 15,2016. The report provides good discussion of recent studies
on the natural occurrence of hexavalent chromium in areas containing ultramafic
source materials, the role of Mn-oxides in oxidizing Cr(lll) and mobilizing Cr(VI), and
observed positive correlations between nitrate and Cr(VI) in groundwater throughout
California and the western Sacramento Valley. The report is dismissive of on-site waste
disposal for the source of Cr(VI); potential waste sources should be more thoroughly
evaluated in the absence of historical records of use and disposal of chromic acid.
Recommendations were provided for evaluating site background concentrations
for hexavalent chromium; graphical representation of chromium concentration
distributions on cumulative frequency diagrams can be used to analyze site data in
relation to available data from nearby locations. Data collection activities should
be initiated to support the site conceptual model, for example, to identify if Mn(ll) is
mobile in the vadose zone, to determine if Mn is present in groundwater in HSU-1, and
to support the proposed connection between Mn oxidation and Cr(VI) production.
TECHNICAL SUPPORT VIDEO CONFERENCE
Parris Island Marine Corp Recruit Depot, Site 45
Technical Assistance Region 4: On April 21,2015, Dr. Scott Huling (GWERD) provided a
presentation to the EPA Region 4 remedial project manager, Lila Llamas, and staff from
the US Navy, US Marine Corp, South Carolina Department of Health and Environmental
Control,TetraTech Inc., and EnSafe Inc. The presentation was a summary of in-situ
chemical oxidation (ISCO) research activities at the Parris Island Marine Corp Recruit
Depot, Site 45 (Beaufort, SC). Site characterization activities included pre- and post-
oxidation collection and analysis of soil cores, and installation of micro-wells and pre-
and post-oxidation groundwater sample collection and analysis. The ISCO pilot scale
demonstration study involved three rounds of sodium permanganate oxidant injection
utilizing various injection methods (direct push injection, injection well, direct-push
injection well). A low cost, mobile, injection system was designed, built, and deployed,
and oxidant injections occurred over a 10 month period in a PCE source area where
numerous subsurface and surface utility impediments were present.The oxidant
injection design involved heavy oxidant loading (mass, volume), and the injection
strategy included short vertical injection intervals, narrow ROI's, low injection pressure,
top-down/outside-in injection to minimize the role of heterogeneities and to achieve
greater probability of oxidant delivery to targeted zones. While significant destruction
of CVOCs was achieved, post-pilot study oxidant injection was recommended to
further achieve treatment objectives.
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Scientific and Technical PublicatiSs
Huang, Junqi. (GWERD), John A. Christ (Dept. of Civil and Environmental Engineering,
US Air Force Academy, Colorado), Mark N. Goltz (Air Force Institute of Technology
(AFIT), Wright-Patterson AFB, Ohio), and Avery H. Demond (University of Michigan,
Ann Arbor, Ml). (2015). Modeling NAPL dissolution from pendular rings in idealized
porous media, Water Resources Research, 51, doi:10.1002/201.5WR016924.
Burden, David S. (GWERD). 2015. Ground Water Technical Support Center (GWTSC)
Annual Report Fiscal Year 2014 (FY14). EPA 600/R-15/237.
Burden, David S. (GWERD), John L. McKernan (LRPCD, Felicia Barnett (Region 4). 2015.
Research Summary EPA Technical Support Centers (TSC): FY14 Lessons Learned.
EPA 600/S-15/239, September 2015, Innovative Research for a Sustainable Future.
Faulkner, Barton R. (GWERD), Leibowitz, Scott. G. (NHEERL, Western Ecology Division),
Canfield, Timothy. J., Groves, Justin. F. (GWERD). 2015. Quantifying groundwater
dependency of riparian surface hydrologic features using the exit gradient.
Hydrological Processes, doi: 10.1002/hyp.10766.
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About the Groundwater, Watershed, and
Ecosystem Restoration Division (GWERD)
The Groundwater, Watershed, arid Ecosystem Restoration Division (GWERD), led by
Division Director Dr. Richard Lovvrance, pursues areas of investigation that are part of
the Office of Research and Development's (ORD) Strategic Plan and the mission of the
National Risk Management Research Laboratory. GWERD is EPA's center of expertise for
investigation of the soil and subsurface environment and ecosystem restoration.
GWERD conducts research and engages in technical assistance and technology transfer
on the chemical, physical, and biological structure and processes of the subsurface
environment, the biogeochemical interactions in that environment, and alterations to
other environmental media.To carry out its mission, the division is divided into three
branches: Subsurface Processes and Protection Branch; Watershed, Ecosystem, and
Subsurface Research Branch; and Technical Assistance and Technology Transfer Branch.
In addition, GWERD's Science Research Council oversees and guides the scientific
focus of the division and is supported by individual research teams and principal
investigators who provide direction for approved projects and specific efforts.
A broad range of expertise and scientific disciplines are represented at GWERD,
with professionals who are microbiologists, chemists, hydrologists, ecologists,
environmental scientists, geochemists, soil scientists, chemical and environmental
engineers, and modelers.
The Robert S. Kerr Environmental
Research Center (above, circa 1966
and at right, circa 2016) houses
the Groundwater, Watershed, and
Ecosystem Restoration Division.
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