5
\
Tl
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/A newsletter about soil, sediment, and groundwater characterization and remediation technologies
Issue 52
Z«w mt/e o/Technology News and Trends highlights techniques to enhance site investigations
through advanced data integration and high resolution technology such as membrane interface
probes, electrical resistivity imagery, and compound specific isotope analysis. In addition to
improving the conceptual site model, use of these field and laboratory tools can aid in the
selection of innovative design, construction, and monitoring approaches facilitating increased
use of in situ cleanup remedies.
Revised Characterization Plan Accelerates Petroleum
Brownfield Cleanup and Redevelopment
March 2011
Efforts to better delineate contamination
and accelerate remediation of the former
Fannon Petroleum Services site in
Alexandria, VA, were initiated in the early
2000s as part of a plan to redevelop the site
for residential use. Strategically located
near the Potomac River in "Old Town"
Alexandria, the site had been used as a fuel
depot since the 1880s. Discovery of up to
40 inches of petroleum product in
monitoring wells near the site in the early
1980s prompted a preliminary site
investigation and recovery of oil. Continued
high concentrations of dissolved
contaminants, slow rates of oil recovery, and
the property's high potential for
redevelopment collectively prompted an
effort to better define the nature and extent of
contamination, identify all areas needing
remediation, and characterize the risk
associated with remaining contamination.
Project success is attributed to combined
efforts of the property owner, the Virginia
Department of Environmental Quality (VA
DEQ), and the City to address the site's
environmental and economic issues.
Historical records suggest that 50,000 gallons
of fuel could have been released since 1962
due to poor procedures for handling and
storing materials such as gasoline, diesel,
kerosene, ethanol, and methanol. When the
petroleum product was discovered by utility
maintenance crews working at neighboring
properties in 1982, the high volume of fuel
suggested that the utility work had ruptured
an underground fuel line. After several years
of oil recovery by the site owner, groundwater
monitoring in the early 1990s identified a free-
phase plume extending from the underground
storage tank (UST) and loading rack area. By
the late 1990s, monitoring indicated that the
contaminant plume had migrated to offsite
properties as far as 300 feet from the
suspected source area. An onsite
groundwater pump-and-treat (P&T) system
and soil vapor extraction system began
operating in 2001 to treat subsurface areas
targeted through investigations relying on
conventional sampling techniques.
Groundwater was extracted for treatment at a
rate of approximately 6 gal/hr.
As part of the plan for improved site
characterization and accelerated cleanup, the
VADEQ initiated the Triad approach. Project
planning included development of a
conceptual site model and consensus on
specific investigative methods and tools, with
a focus on using: (1) a membrane interface
probe (MIP) to characterize distribution of
volatile organic compounds (VOCs) in
discrete hydrologic units and soil
stratigraphy at offsite locations; (2) direct-
sensing geophysical tools rather than
groundwater and soil sampling for initial
screening; and (3) a dynamic work strategy to
[continued on page 2]
Contents
Revised Characterization
Plan Accelerates
Petroleum Brownfield
Cleanup and
Redevelopment page 1
ERI Survey Helps
Delineate TCE Plume
and Guide Field
Testing of Innovative
ISCO Candle
Technology page 3
3D-CSIA Forensics
attheFAMULaw
School Site Reveals
Multiple Contaminant
Sources page 4
CLU-IN Resources
Extensive information about
contaminated site character-
ization and monitoring is
available on the U.S. Environ-
mental Protection Agency's
(EPA's) CLU-IN web host.
Topics currently include typical
uses, components, operational
modes, performance specifica-
tions, and verification reports
on 20 analytical, direct-push,
and geophysical tools. Learn
more at: www.cluin.org/
characterization/.
Recyc led/Recycl abl e
Printed wilh Soy/Canola Ink on paper thai
contains at least 50% recycled fiber
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[continued from page 1]
allow real-time decision making that could
identify specific locations for direct-sensing
locations as work proceeded. Onsite areas
of contaminated material were delineated for
excavation and offsite disposal during the
anticipated residential construction.
In early 2006, MIP data mapping began
on the properties and streets adjacent to
and downgradient of the fuel depot. The
use of MIP technology at Fannon
involved a portable controller and a direct-
push rig to advance a probe into the
subsurface for the purpose of heating the
soil, water, and vapor matrix. The heated
VOCs were drawn across a permeable
membrane near the tip of the probe and
carried by an inert purge gas through
small-diameter tubing connected to a
sensor detection system at ground
surface. The detection system consisted
of three direct-sensing tools: a
photoionization detector (PID), a flame
ionization detector (FID), and an electron
capture detector. Along with a portable
gas chromatograph for periodic
confirmatory analysis, these detectors
helped delineate subsurface zones of
petroleum product and specific types of
VOCs. All detection, analytical, and
control equipment was transported in a
standard utility vehicle traveling a few feet
in front of the direct-push rig (Figure 1).
An average of five probes were advanced
daily, each resulting in a continuous,
vertical 30- to 40-foot profile of the
subsurface with more than 20 data points
per foot. Chemical and geological data
from each profile included VOC
concentrations identified through PID and
FID, soil conductivity, and temperature
measurements. Electronic displays of the
profiles and associated three-dimensional
(3 -D) maps were viewed in the field by the
VADEQ, the site owner's environmental
consultant, City staff, and other
stakeholders for better-informed and
faster decisions. MIP data were collected
through a total of 44 probes during a
single mobilization spanning two weeks. The
survey was terminated once the VADEQ and
environmental consultant agreed on the
extent and severity of the offsite plume.
The MIP results generally correlated with
the plume defined by earlier, conventional
methods but identified a previously
unknown offsite lobe of contamination.
Conceptual model refinement indicated a 60-
by 120-foot plume at a depth of 15 feet below
ground surface (bgs). High resolution
mapping of the lobe suggested that the free-
phase plume intersected and then migrated
along the municipal sanitary/storm sewer
system. This area of contamination, which
years of conventional investigation had
failed to identify, accounted for the
significant offsite contamination discovered
during the 1982 utility work. Overall results
indicated that removal of the source area
during residential construction should
prevent further plume migration. MIP
mapping also led to identification of an
alternate location for the remedial system on
a downgradient adjacent property.
Twenty-eight USTs, underground piping,
the terminal loading rack, and
approximately 35,000 tons of petroleum-
contaminated soil subsequently were
excavated and removed from the source
area. The remedial system was concurrently
transferred to its new location, and several
new extraction wells were installed to
supplement existing offsite recovery wells.
Costs for MIP deployment and onsite
detection and analysis equipment for
several weeks of field work totaled
approximately $55,000. In contrast, earlier
site characterizations through conventional
methods in conjunction with many soil and
groundwater sample analyses had cost
hundreds of thousands of dollars and
numerous mobilizations over multiple years
Conventional sample analysis now
indicates that the P&T system is
hydraulically controlling the contaminant
plume and reducing the remaining free-
phase fuel oil and dissolved-phase
groundwater contaminants. The system
will continue operating until the VA
DEQ-approved risk-based cleanup
goals are met.
To date, the P&T systems have treated
over 6 million gallons of petroleum-
contaminated groundwater and removed
over 4,200 pounds of total petroleum
hydrocarbons, 350 pounds of benzene,
toluene, ethene, and xylenes (BTEX), 78
pounds of methyl-tertiary-butyl ether
(MTBE), and 15 pounds of naphthalene.
An estimated 5,000 gallons of fuel oil have
been recovered, and nearly 7,000 pounds
of subsurface petroleum vapors have
been removed.
Remedial actions specified in the
redevelopment plans (per the city's
contaminated land program) included a
vapor intrusion abatement system
comprising an upgraded vapor barrier,
active sub-slab ventilation, and a treatment
unit for groundwater drainage to eliminate
any potential risks of exposure from the
development. Use of MIP also enabled
stakeholders to revise the site's
construction plan to include a depth
[continued on page 3]
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[continued from page 2]
restriction for anticipated structures.
Residential construction began in 2008
and was completed in 2010.
Contributed by Randy Chapman, VA
DEQ (randy.chapman(a)deq.virginia.gov
or 703-583-3816) and Daniel Imig, City
of Alexandria Office of Environmental
Quality (daniel.imig(a),alexandriava.gov
or 703-746-4070)
More About Accelerating Urban Brownfield Cleanup
EPA partnered with the New York City Office of Environmental Remediation to compile
the report, Streamlining Site Cleanup in New York City (EPA 542-R-10-005). The
report presents a plan for using the Triad approach and associated best practives to
characterize sites and optimize remediation of low to moderately contaminated land
while addressing a municipal need to sustainably develop commercial, residential, and
recreational properties. Use of Triad in the New York metropolitan area has shown significant
advantages for brownfields redevelopment programs, including those involving old fill
areas and waterfront property. Access the report from EPA's Brownfields and Land
Revitalization Techno logy Support Center at: www. bro wnfieldstsc. org/.
ERI Survey Helps Delineate TOE Plume and Guide Field Testing of Innovative ISCO Candle Technology
A 1989 investigation by the Nebraska
Department of Environmental Quality
(NDEQ) found a high concentration (37,000
Hg/L) of trichloroethene (TCE) and other
VOCs in shallow groundwater near a closed
cell of a former municipal landfill in Cozad,
NE. Using funds from an NDEQ landfill
closure grant, the City conducted numerous
site investigations and installed several
remedial measures. By 2008, however, annual
groundwater monitoring indicated that the
average TCE concentration in groundwater
remained elevated at 688 ug/L. WithNDEQ's
and the City's concurrence, the University
of Nebraska-Lincoln (UNL) began an effort
in 2009 to investigate new tools for
subsurface characterization and field test an
alternative remedial technology. Project
funding was provided to UNL by the U.S.
Congress and administered by EPA through
a cooperative agreement.
The City of Cozad had owned and operated
the landfill until 1987, when the facility was
closed due to noncompliance with the State's
new regulations on small municipal landfills.
The site's unlined 400- by 40-foot waste cell
extends 20 feet bgs and is capped with a thin
layer of clay soil. Approximately 5 feet of
silty clay separates the bottom of the cell
from 3 5 feet of alluvial sand, which overlies
the Ogallala member of the High Plains
Aquifer. The City's early site investigation
included installing 19 groundwater
monitoring wells to depths of 8-170 feet bgs.
As of 2008, groundwater modeling estimated
a VOC plume about 600 feet long, 125 feet
wide, and 20 feet deep. Limited success of
the remedial attempts, which included a dual-
phase extraction well system, poplar trees to
induce phytoremediation, and several
volatilization ponds, was attributed to low
permeability of the aquifer and insufficient
characterization of the contaminant plume.
The subsequent UNL investigation used
electrical resistivity imaging (ERI) to
characterize the closed cell area. Grid and
boundary lines of the survey were based on
historical TCE groundwater concentrations,
proximity of the highest TCE concentrations
to a targeted (east) portion of the cell, existing
poplars and evaporation ponds, and property
lines representing legal points of compliance.
Over three days in September 2009, images at
more than 7,100 data points were collected
along 22 survey lines.
ERI results identified three distinct
conductivity layers in the substrata, which
corresponded to differences in lithology and
hydraulic conductivities. The ERI maps were
used to guide groundwater sampling via direct
push technology. Soil and groundwater
samples were collected from depths of 5-69
feet bgs at 64 locations. Results of this focused
sampling effort indicated that the vast majority
of contamination was contained in a layer of
low-permeability loess near the water table,
within 20 feet of the ground surface. Not all of
the loess was found to be contaminated, but
essentially all of the contamination was located
in this low permeability layer.
With technical assistance from UNL, the ERI
survey was performed in part by Oklahoma
State University faculty at a discounted
research-based cost of $9,000. Costs for
groundwater sample collection and analysis
(completed primarily by UNL graduate
students) totaled approximately $17,000.
When compared to commercial projects,
NDEQ estimates a significant savings in field
and analytical labor expenses attributable to
the project's academic partners.
Improved understanding of the site's
remedial progress and current extent of
contamination enabled project partners to
explore lower-cost remedial technologies,
particularly in situ chemical oxidation (ISCO).
Conventional ISCO by injecting liquid
oxidants into groundwater was anticipated
to be unsuccessful, due to the low aquifer
conductivity within the target area. Instead,
slow-release potassium permanganate
candles (SRPCs) were selected for use on a
pilot-scale basis. SRPCs consist of granular
potassium permanganate (KMnO4)
embedded in a paraffin wax matrix. Earlier
laboratory SRPC studies by Ohio State
University demonstrated that the KMnO,,
J 4
slowly dissolves and diffuses through the
wax matrix upon contact with water. The
MnO4~ can then react with chlorinated
solvents such as TCE and reduce them to
CO2andCh
UNL researchers developed an in-house
SRPC production process, conducted
bench-scale tests to quantify the SRPC
dissolution rates, and designed an SRPC
system to be applied at the landfill.
[continued on page 4]
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[continued from page 3]
Treatability study results (using core samples
collected from the site) indicated KMnO4
breakthrough across 1.74 cm of soil occurred
within 24 hours for most samples. Laboratory
performance of miniature SRPCs predicted a
lifespan of 7.5 and 16.5 years, respectively.
for two- and three-inch-diameter SRPCs.
based on a predicted MNO4 release rate of 3
grams/day in each treatment well. Additional
trials at UNL included testing the potential
explosion hazard of a full-scale 3 -inch candle.
Failure to explode during cap blasting
supported earlier laboratory findings that the
presence of paraffin wax avoids the explosion
risk posed by dry permanganate.
With technical oversight from NDEQ, a total
of 50 three-inch and 105 two-inch SRPCs were
installed in July 2010; each SRPC was three
feet long. The three-inch SRPCs were inserted
into tailored containers and placed inside 4-
inch-diameter wells installed using direct
push technology on 4-foot centers to a depth
of 22 feet (Figure 2). The two-inch SRPCs
were placed directly into the aquifer at 5-foot
increments through use of hollow direct-push
rods (on 2-foot centers) reaching 22 feet bgs.
Collectively, the candles contained
approximately 1,400 pounds of KMnO4 and
300 pounds of paraffin. Upon oxidant
diffusion, the emplaced materials would
Figure 2. As part oflSCO implementation
at the former Cozad landfill, five 3-foot
KMnO ^paraffin candles were vertically
stacked in a slotted holder and lowered
into each often groundwater wells.
groundwater sampling shows no evidence
of impacts on the deeper Ogallala Aquifer.
essentially create a 20-foot-wide permeable
reactive barrier intersecting the plume portion
with highest TCE concentrations.
Groundwater sampling conducted 85 days
after SRPC installation indicated an 80-85%
reduction of total VOC concentrations in
treatment zone monitoring wells. Sampling
results from one shallow well within the
treatment zone, for example, exhibited a TCE
concentration approaching 400 |J,g/L prior to
SRPC installation and a post-treatment TCE
concentration of approximately 75 |J,g/L.
Detection of MnO4" in a deeper well indicated
diffusion of the slow-releasing oxidant had
started to occur, which supported prediction
that uniform KMnO4 distribution throughout
the target subsurface area could occur in 6-12
months after installation. Currently, the TCE
concentration in the downgradient point of
compliance well is slightly below the 5 |lg/L
federal maximum contaminant level (MCL), and
Pilot study costs for the SRPC installation
total approximately $18,000 to date; this
includes $4,000 for chemicals and $14,000
for installing the monitoring wells and SRPC
wells and renting direct push equipment.
Pending SRPC efficacy inmeetingthe State's
groundwater protection standard for TCE
(below 5 |J,g/L), NDEQ anticipates the City
will oversee the SRPC system after UNL
work is complete. Future evaluation of
whether changes can be made to the existing
remediation systems also is anticipated, to
reduce operation and maintenance costs
while still meeting the cleanup goals within
20 years.
Contributed by Steve Comfort and Mark
Christenson, UNL (scomfort(q)unl. edu or
402-472-1502), Laurie Brunner, NDEQ
(laurie. brunner(a)nebraska. gov or 402-
471-2214), and Kenneth Rapplean, EPA
Region 7 (rapplean.kenneth&.epa.gov
or 913-551-7769)
3D-CSIA Forensics at the FAMU Law School Site Reveals Multiple Contaminant Sources
The Florida Department of Environmental
Protection (FL DEP) recently conducted
a 3-D compound-specific isotope
analysis (3D-CSIA) investigation at the
Florida Agricultural and Mechanical
University (FAMU) Law School site in
downtown Orlando. This 3D-CSIA was
undertaken as part of a multiple lines of
evidence approach to determine potential
sources of groundwater contamination.
Previous FAMU-sponsored groundwater
investigations identified widespread
chlorinated hydrocarbons at concentrations
exceeding Florida Primary Drinking Water
Standards (FPDWS). To better understand
potential sources of these contaminants,
the FL DEP examined isotope ratios of the
three elements (13C/12C, "Cl/^Cl, and 2H/'H)
in the primary contaminants of concern,
tetrachloroethene (PCE), TCE, and cis-1,2-
dichloroethene (cDCE).
Since the isotopic ratios of PCE and TCE vary
depending on the manufacturer, 3D-CSIA can
be used to help differentiate sources of the
chlorinated solvents and determine the
sequence of multiple releases based on a site's
past PCE, TCE, and cDCE usage. The
technique also can help identify, characterize,
and quantify biotic and abiotic transformation
reactions because both biotic and abiotic
degradation processes are associated with
significant isotopic fractionation. Results of
isotope analyses are generally reported as 8
values, e.g., 813C for carbon, 837C1 for chlorine,
and 82H for hydrogen. The 8 symbol
represents a comparison between the ratios
of the different stable isotopes of an
element, such as 13C to 12C, 37C1 to 35C1, and
2H to 'H, and is expressed in parts per
thousand (%o) of an internationally
accepted standard reference concentration.
A 813C of-30%o, for example, indicates that
the ratio of 13C to 12C in the sample is 3%
lower than the standard. A more negative 8
value indicates that a chemical is depleted
in the heavier isotope (13C, 37C1, or 2H).
Biodegradation agents preferentially break
down the lighter isotopes of different
elements, inducing a shift of the residual
[continued on page 5]
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3D Isotope Ratio Signatures and Chlorinated Hydrocarbon Concentrations
Carbon
Chlorine
Hydrogen
Concentration
Potential
Source
Sample
ID
cDCE
(513C)
TCE
(513C)
PCE
(513C)
Former
Dry
Cleaner
DEP-19D
DEP-14D
TCE
(537CI)
PCE
(537CI)
cDCE
(52H)
TCE
(52H)
cDCE TCE PCE
(ppb) (ppb) (ppb)
-28.8
-28.3
2.3
0.8
Other
IS-50'
DEP-9D
-35.8
-34.8
-26.9
-28.8
0.5
0.5
3.3
3.7
Former
Uniform
Rental
MW-1A
MW-1C
MW-1D
-29.9
-27.2
2.5
0.2
0.5
0.2
0.4
Derived Signature Value
Light
Neither
Likely Origin of Compound
Manufactured
Degradation
Table 1. The isotopic ratios of PCE, TCE, and cDCE detected in the wells at the FAMU site suggest multiple releases of
PCE and TCE that are both a result of direct release as well as degradation of PCE.
VOCs detected at concentrations greater
than 10 parts per billion (ppb).
Techniques for collecting and preserving
ground-water samples for 3D-CSIA are
identical to those for VOC analysis using
EPA Method 8620B. In this investigation,
all samples were collected using
standardized techniques and then shipped
to an offsite laboratory. The average cost
for each set of 3D isotopic signatures of
cDCE, TCE, and PCE was $900.
The highest concentrations of PCE
(1,700-24,000 ppb) were detected in the
three wells near the former uniform
rental service (Table 1). The PCE in the
wells have similar 813C and 837C1 ratios,
indicating a major release of PCE from a
single source. The 813C measured in TCE
at MW-1A is indicative of a
manufactured TCE; the significantly
different 837C1 and the very high 82H also
support a manufactured source of TCE
in this well. However, the ratios
measured for TCE in MW-1D indicate
some biodegradation of PCE is
occurring. The lighter 813C, similar 837C1,
and low 82H suggest biodegradation.
[continued on page 6]
[continued from page 4]
compound to a less negative 8 13C value. A
more negative 813C value would suggest a
closer source and more recent release of a
chemical into the environment.
The target investigation area at the
FAMU Law School encompasses
approximately eight city blocks that
include various businesses and
residential complexes. The site is
underlain by about 50 feet of fine- to
medium-grain sand with increasing silt
and clay with depth. The average depth
to the water table is 11 feet bgs. Nearly all
deep groundwater samples collected at
the site were found to contain detectable
levels of chlorinated hydrocarbons, with
many exceeding FPDWS. The highest PCE,
TCE, and cDCE concentrations (Table 1)
were detected in three monitoring wells
located near a former uniform rental service
in the northwestern corner of the study area
(Figure 3). Based on past and current
property uses, other potential sources of
PCE, TCE, and cDCE in the target area
include former dry cleaners, print shops,
and automobile repair shops.
During the winter of 2009, groundwater
samples from seven wells at the FAMU site
were analyzed for both the presence of
chlorinated VOCs and their isotope ratios.
A gas chromatograph coupled with an
isotope-ratio mass spectrometer was used
to determine the isotope ratios for chlorinated
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Solid Waste and
Emergency Response
(5203P)
EPA 542-N-11-001
March 2011
Issue No. 52
United States
Environmental Protection Agency
National Service Center for Environmental Publications
P.O. Box 42419
Cincinnati, OH 45242
Presorted Standard
Postage and Fees Paid
EPA "
Permit No. G-35
Official Business
Penalty for Private Use $300
[continued from page 5]
The cDCE in both wells appears to have
a manufactured origin.
Wells IS-501 and DEP-9D are located even
further downgradient of the former dry
cleaner, but have higher concentrations of
TCE than PCE. The 513C and 537C1 ratios for
PCE in these wells are heavier than for TCE.
suggesting TCE is primarily a product bio tic
transformation. However, the 128%o 82H
in IS-50' indicates the manufactured TCE
may be commingled with a small amount
of TCE that has degraded from PCE.
Wells DEP-19D and DEP-14D, located
downgradient of a former dry cleaner at the
south edge of the site, had similar 813C ratios
for PCE but slightly different 537C1 ratios.
Both matched ratios for manufactured PCE,
potentially indicating the potential use
and release of different PCE formulations
at the former dry cleaner (Table 1).
Costs for 3D-CSIA planning, laboratory
analysis, and data interpretation at the
FAMU site totaled approximately $9,500.
Using this approach, the FL DEP was able
to confirm two hydrocarbon release
sources, as indicated by earlier groundwater
sampling, at the FAMU site. Overall 3D-
CSIA results indicate that the former dry
cleaner and former uniform rental service
were the main contributors to groundwater
contamination. Isotopic data from wells IS-
50' and DEP-9D, however, suggest other
as of yet unidentified sources of
chlorinated hydrocarbons. The FL DEP is
planning remediation of the site as efforts
to delineate other contaminant sources
continues, and anticipates using results of
this study as background information for
future FL DEP investigations.
Contributed by Jeff Newton, Florida
DEP (Jeff.Newton(q),dep.state.fl.us or
850-245-8955), Amber Igoe, TetraTech
(Amber.Igoe(a)tetratech.com or
850-385-9866), and Yi Wang, Ph.D.,
DPRA-ZymaX Forensics Isotope
Laboratory (Yi. Wang(a)zymaxusa.com or
760-781-3338 ext. 43)
Contact Us
Technology News and Trends
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Suggestions for articles may
be submitted to:
JohnQuander
Office of Superfund Remediation
and Technology Innovation
U.S. Environmental Protection Agency
Phone:703-603-7198
quander.iohn@.epa.qov
New Technical Bulletin
EPA's Office of Solid Waste and
Emergency Response recently
issued Best Management Prac-
tices: Use of Systematic Project
Planning Under a Triad Approach
for Site Assessment and Cleanup
(EPA542-F-10-010). Topics include
use of a conceptual site model and
samples of successful systematic
project planning. Access the
bulletin at: www.brownfieldstsc.org/.
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative characterization and treatment
techniques or technologies. The Agency does not endorse specific technology vendors.
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