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u
/A newsletter about soil, sediment, and ground-water characterization and remediation technologies
Issue 40
This issue of Technology News and Trends highlights recent applications of Triad, an inte-
grated site characterization and cleanup strategy that limits decision uncertainty and reduces
project duration and cost. In contrast to using one-time, exclusive steps typical of a linear strat-
egy, Triad approaches conceptual site model development, planning, data review, characteriza-
tion, and remedy implementation as real-time, evolving, iterative procedures. Applications de-
scribed in this issue illustrate how direct sensing tools, field-based analytical methods, innova-
tive sampling design, and data visualization and communication provide high-density, defen-
sible datasets within a range of regulatory frameworks.
Triad Use at Naval Base San Diego Saves an Estimated
Six Years and $3 Million for Site Investigation
The U.S. Naval Facilities Engineering
Command Southwest (NAVFAC SW)
used the Triad approach to collect an
integrated hydrogeologic and chemical
dataset for expediting and optimizing
characterization of a volatile organic
compound (VOC) plume at Naval Base
San Diego (NBSD), CA. The 295-acre
"IR Site 22" was identified in 2003 when
VOC concentrations reaching 100 mg/L
were reported in an upgradient well as
part of a remedial investigation at
"NBSD IR Site 4." As a result, NAVFAC
SW initiated investigative actions to
identify potential sources of VOC
contamination in ground water,
determine whether the source(s) were
caused by Navy activities, and delineate
VOCs in ground water.
IR Site 22 is located approximately three
miles southeast of downtown San Diego,
on the east side of San Diego Bay. The
site comprises reclaimed tidal lands
covered by dredged material, and
encompasses privately owned commercial
and industrial properties in addition to
the NBSD.
IR Site 22 investigations leveraged all three
elements of Triad:
The stakeholder team initiated a system-
atic planning process early in the
project; stakeholders included NAVFAC
SW, the Space and Naval Warfare Sys-
tems Center (SPAWAR), the California
Regional Water Quality Control Board,
and the California Department of Toxic
Substances Control. The team collabo-
rated in developing data quality objec-
tives (DQOs) and the conceptual site
model (CSM), which was used to de-
sign a technical approach. Regulators
visited the site several times during field
work to participate in data interpreta-
tion and decisions to "step out" sam-
pling to additional locations.
Field staff collected real-time in situ
measurements using a site character-
ization and penetrometer system
(SCAPS) truck equipped with onboard
cone penetrometer testing and a mem-
brane interface probe (CPT/MIP) and
a direct sampling ion trap mass spec-
trometer (DSITMS).
Stakeholders collaborated in developing
a dynamic work strategy to allow the
field team to step out dynamically to
meet project-specific DQOs. Web-
based, near-real time communication of
[continued on page 2]
January 2009
Contents
Triad Use at Naval
Base San Diego
Saves an Estimated
Six Years and $3
Million for Site
Investigation page 1
Single Field
Mobilization
Completes Site
Investigation and
Removal Actions page 3
Triad Expedites
Brownfields
Redevelopment
in Fairbanks page 4
Online Resources
The Triad Resource Center
offers technical tools and
documents on systematic
planning, dynamic work
strategies, sample acquisition
and handling, measurement
and data management,
and regulatory acceptance
for Triad applications
(http://www.triadcentral.org/).
This web site also provides
project profiles highlighting
cost and time savings at
specific sites.
Recycled/Recyclable
Printed with Sny'Canola |nt{ en paper thai
contains at least 50% recycled fiber
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Possible Contributor
|_ | IR Site 22 Study Area
| | Naval Base San Diego
PCE in Ground Water
Concentration (ug/L)
High: 1673.28
[continued from page 1]
project data allowed stakeholders to
view daily reports and remain engaged
in the project as the CSM evolved.
The field work was conducted in three
phases. Between each phase, a
systematic planning meeting was held
to present current data and the updated
CSM and to optimize the following
work phase.
Phase I involved a two-week lithologic
and dense non-aqueous phase liquid
(DNAPL) investigation using CPT with
MIP and DITMS to build a detailed
lithologic site model and identify VOC
source area(s). A total of 35 borings
were advanced to depths reaching 58
feet below ground surface (bgs).
Lithologic data from CPT were used to
augment existing information and
expand the CSM. Results indicated three
potential VOC source areas.
Phase II comprised a four-week, site-
wide investigation of ground water.
Using Phase I CPT and MIP data to
optimize locations and screened
intervals, a total of 24 direct-push
temporary ground-water wells were
installed to depths of up to 40 feet bgs.
Each temporary well was constructed
using nominal 3/4-inch PVC casing with
a 10-foot screened interval. Ground-
water samples were collected for 24-
hour-turnaround VOC analysis by a
fixed-base laboratory using U.S. EPA
Method 8260B. Eleven of the wells were
surveyed to determine hydraulic gradient
across the site.
Following evaluation of Phase I and II
results, Phase III was initiated to address
data gaps regarding the extent of
dissolved VOC plumes, include potential
preferential pathways in the refined CSM,
and assess continuity between identified
VOC source areas and VOCs
independently identified in IR Site 4
ground water. This eight-week phase
involved collecting lithologic data from
16 CPT borings, installing 22 additional
temporary wells, and collecting ground-
water samples for laboratory analysis
of VOCs.
The collaborative data revealed two VOC
plumes including tetrachloroethene
(PCE) originating from offsite sources
on private properties (Figure 1). Results
also suggested contaminant migration
favoring a subsurface paleochannel
preferential pathway. In total, the SCAPS
project team collected 2,775 vertical feet
of lithologic data and 790 linear feet of
VOC concentration data representative
of the 295-acre site. The collaborative
dataset included analytical results from
49 ground-water samples.
Triad implementation provided an
expedited high-density dataset and a
refined CSM in near-real time, resulting
in cost avoidance estimated at $3 million
and schedule savings of approximately
six years. The Navy continues to work
with regulatory stakeholders in
developing a remedial strategy for IR
Site 22.
Contributed by Jim Leather, Ph.D.
SPAWAR System Center
(jim.leather(q)navy.mil or 619 -553-
6240) and Karen Collins, Richard
Brady & Associates
(kcollinsCAr brady.net or 858-634-4516)
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Single Field Mobilization Completes Site Investigation and Removal Actions
The Kentucky Research Consortium for
Energy and the Environment (KRCEE)
worked with the U.S. Department of
Energy (DOE) last summer to introduce
new approaches and technologies to the
site cleanup program operating at the
Paducah Gaseous Diffusion Plant
(PGDP) in western Kentucky. A Triad
demonstration was conducted at
PGDP's Area of Concern (AOC) 492
that integrated several real-time
characterization tools into dynamic work
strategies (DWSs) for expediting
characterization and remediation within
one field deployment. Field work focused
on methods to address uranium and
polychlorinated biphenyls (PCBs), two
of the most common soil and sediment
contaminants at PGDP. Those methods
included laser-based gamma "walkover"
surveys (GWS), x-ray fluorescence
(XRF), in situ gamma spectroscopy
(ISGS), PCB immunoassay kits, multi-
increment sampling (MIS), and adaptive
compositing (AC).
The PGDP has operated for more than
50 years and is now the only active
uranium enrichment facility in the United
States. Past operations released
contaminants to ditches that emptied into
neighboring streams, contaminating
sediments. Maintenance activities within
the streams and ditches resulted in
contaminated sediments being placed
on streams banks and adjacent upland
areas including AOC 492. Limited
historical information (three surface
samples) identified uranium and PCB
concentrations of 1,150 and 44 ppm,
respectively, in AOC 492 surface soil.
In the fall of 2007, a group of technical
representatives from EPA Region 4, the
Commonwealth of Kentucky, DOE,
KRCEE, and Argonne National
Laboratory (ANL) collaborated in a
systematic planning session to devise
the initial CSM and form the project's
DWSs. The session yielded default risk-
based, wide-area averaged and hot spot
project criteria of 11 and 99 ppm,
respectively, for uranium and 3.6 and 33
ppm for PCBs. It also identified three
exposure units—based on a teenage
recreational user exposure scenario—
within AOC 492. Based on an
understanding of uranium processing
and past experience, PCBs were
expected to be collocated with uranium
contamination. The field strategy
included three activities deployed in one
field effort: characterizing the level and
extent of soil contamination, excavating
soil with concentrations exceeding
project criteria, and demonstrating post-
excavation that project criteria were
attained for each of the exposure units.
The laser-based GWS for determining the
presence of elevated gamma radiation in
near-surface soil was the first tool to be
deployed. Approximately 24,000 GWS
data points were collected over the
course of three days, providing spatially
dense information (an average of four
measurements per square meter) about the
location of uranium contamination in near-
surface soil. Based on the GWS data, twenty
locations were further sampled and analyzed
by XRF and ISGS. The selected locations
spanned the range of GWS results; the
XRF/ISGS data were used to develop a
relationship between GWS results and
surface soil uranium concentrations. Once
that relationship was established, uranium
hot spots could be identified based on
GWS data (Figure 2), and the layout of
exposure units modified to reflect the
spatial distribution of contamination.
Approximately 13 m3 of soil were
subsequently removed from the uranium
hot spots and placed in an offsite disposal
facility. GWS and in situ XRF readings
verified that the excavation surface complied
with the project hot spot criteria.
MIS and AC sampling techniques were
used jointly with the PCB immunoassay
kits to verify that PCB hot spots did not
exist for the two exposure units
considered most likely impacted by
contamination. MIS uses soil collected
from multiple locations spread
systematically across a decision unit to
form a sample that is more representative
of the average conditions across an area
than any one individual sample location
would be. AC combines samples from
adjacent decision units into composites
before analysis; during the compositing
process, the contributing samples are
split, with one half of the splits archived
for possible later analysis and the other
half used to make the composites. Field
investigation levels are defined as a
function of the number of samples
contributing to the composite and the
original project criteria. If the analytical
results of a composite exceed the field
investigation level, each of the archived
sample splits contributing to the
composite is analyzed. Use of MIS and
AC minimized the number of sample
analyses needed; only 23 were
necessary to verify compliance with hot
spot and area-averaged cleanup criteria
for the entire study area. More than 300
analyses would have been required if
each of the soil increments had been
analyzed individually.
Rigorous data quality control (e.g., use
of calibration standards and control
charts) was developed and implemented
for the project to ensure technically
defensible datasets were obtained from
field analytics. Data quality for the XRF
uranium measurements was comparable
to standard laboratory alpha
spectroscopy data quality, with a
correlation coefficient of 0.99 and
detection limits at background levels.
Each sample analyzed by immunoassay
also was analyzed at an offsite
laboratory for confirmation. In general,
the PCB immunoassay kits compared
favorably with laboratory total PCB
[continued on page 4]
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Figure 2. GWS results identified a
uranium hot spot in surface soil at PGDP
AOC 492.
[continued from page 3]
data, with a correlation coefficient
greater than 0.9.
The field work generated more than
20,000 individual GWS data points,
several hundred XRF measurements,
and almost 400 surface soil increments.
Characterization of AOC 492,
contaminated soil removal, and
verification that project criteria had been
achieved were completed in just 10 days
of field work. The use of MIS and AC
significantly reduced the number of soil
samples requiring analysis, while the
use of field analytics reduced the cost
of each sample analysis. The availability
of real-time data (e.g., XRF, ISGS,
GWS, and PCB immunoassay kit
results) allowed a seamless integration
of characterization, remediation, and
verification sampling. Demonstration
results indicated that use of Triad and a
suite of investigative tools effectively
characterized the soil, identified locations
GWS counts per minute
< 10,000
10,000- 17,000
• > 17,000
15 30
60 Feet
requiring remediation, guided soil
removal, and verified that cleanup criteria
were achieved.
Contributed by Rich Bonczek, DOE-
Portsmouth/Paducah Project Office
(Rich.Bonczek(q),lex. doe, gov or
859-219-4051), Steve Hampson,
KRCEE (502-564-8390 or
skhampson(a)alltel.net), and Robert
Johnson, ANL (rljohnson(q),anl. gov or
630-252-7004)
Triad Expedites Brownfields Redevelopment in Fairbanks
The Fairbanks North Star Borough
(FNSB) used Triad in 2006-2007 to
assess environmental conditions at a
municipal properly along the Chena River
in Fairbanks, AK. FNSB accelerated the
site investigation as part of a brownfields
assessment grant received from the U.S.
EPA in 2005. Low-level contamination
had been identified onsite in past
investigations, but its extent and impact
on future redevelopment had not been
evaluated. FNSB anticipates integrating
the property into a 101-acre "Chena
Riverbend" multi-use project.
The 22-acre area of concern encompasses
the "Old City Landfill," an auto
impoundment where petroleum and
metal contaminants may have been
released, and a municipal snow piling
area potentially contributing polycyclic
aromatic hydrocarbons (PAHs), total
petroleum hydrocarbons, and metals from
melt water. From 1951 until 1965, the
unregulated landfill was used for
municipal debris potentially containing
multiple contaminants of concern (COCs).
The site subsequently was covered with
5-20 feet of clean fill and developed for
recreational use.
The underlying soil consists of alluvial sand
and gravel deposits with interbedded silty
overbank deposits up to 500 feet thick.
Ground water is shallow (8-15 feet bgs)
and generally flows toward the adjacent
river. Limited Phase I investigations in
2005 focused on ground-water and soil
conditions in and below the landfill.
Results indicated PCB and lead
concentrations in soil within the landfill
exceeding regulatory criteria, as well as
slightly elevated manganese and thallium
concentrations in ground water.
The Alaska Department of Environmental
Conservation (ADEC), U.S. EPA Office
of Superfund Remediation and
Technology Innovation, and U.S. Army
Corps of Engineers-Seattle District
assisted FNSB in Triad planning and
implementation, including establishing
and refining the CSM. Key issues
[continued on page 5]
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[continued from page 4]
concerning site development on the
landfill included gas emissions, potential
leachate, and the vertical and horizontal
extent of debris. A high-level decision
flowchart was developed to correlate
release/risk identification to site
redevelopment strategies.
Investigation activities included geophysical
surveys, in situ soil-gas monitoring, test
pit excavation and soil sampling, monitoring
well installation, and ground water
sampling. A detailed flowchart was
established to allow CSM updates in the
field and provide criteria for decisions such
as sampling locations. For example,
preliminary soil-gas sampling plans were
designed on standard 300-foot grids in
accordance with EPA guidance for
investigating landfills (EPA600-R-05-123).
Field decisions allowed for adding sampling
locations within and outside the original
grids and included triggers for additional
sampling supporting future modeling of
vapor pathways. (Initial ambient air
monitoring activity was cancelled due to
ground cover by snow and consequent
reduction in fugitive gas emissions.)
To maximize application of Triad in a real-
time environment, FNSB's contract
mechanism reflected flowchart options on
a unit cost basis to allow for maximum
flexibility during field work. Field
investigations began in October 2007 with
mobilization of drill rigs, excavators, and
a field laboratory. Work started with a one-
week geophysical survey using ground
penetrating radar to confirm the landfill's
areal extent (as determined in Phase I
investigation) and determine the landfill
depth. Survey results confirmed that the
landfill was confined to the western part
of the site (Figure 3) with soil fill and
debris extending 25 feet bgs.
This information was used in real time to
adjust sampling locations for soil-gas and
ground-water sampling. Soil probes were
advanced above the landfill to depths of 7-8
feet, and one soil-gas sample was extracted
from each probe. Hand-held flame
ionization detectors (FIDs) and
photoionization detectors (PIDs) were
used to field screen each sample. Those
showing hits were analyzed for VOCs using
a portable gas chromatograph (GC) housed
in a nearby trailer. Due to slow throughput
of the field GC, some samples were
submitted to a fixed laboratory for VOC
analysis; samples were selected from
locations of low or non-detect PID
readings across the landfill footprint.
Over one week, 94 soil gas samples were
collected, 41 samples were analyzed with
an onsite GC, and 6 samples were
submitted to the offsite laboratory.
Results from the PID screening of soil gas
predicted higher and more extensive VOC
concentrations than the other methods.
PID readings indicated concentrations of
0-165 parts per million by volume (ppmv),
while field GC and fixed laboratory results
indicated only two detections, which were
below 1 ppmv. This difference suggested
presence of volatile compounds with
ionization potentials less than 10.6 EV,
which were not included in other analyses.
The six fixed-laboratory results indicated
that field screening results may not have
quantified soil-gas concentrations. Fixed
laboratory results indicated presence of
benzene and PCE above ADEC draft
screening levels of 3.1 and 8.1 (ig/m3,
respectively. Other compounds such as
trichloroethene and carbon tetrachloride
also exceeded screening levels in at least
one location. PID measurements were
not detected for three of the samples at
these locations due to detection limits
higher than the fixed laboratory's.
Laboratory results also did not agree with
field GC data showing non-detects (with
the exception of one sample) and
generally indicated interference from
non-target hydrocarbons. Although the
methods did not agree with respect to
concentrations, all three methods
indicated VOC presence above screening
levels throughout the landfill. This
information was deemed sufficient for
planning purposes.
Traditional, non-Triad methods were
used to initially investigate the auto
impound and snow piling areas. Six test
pits were excavated and soil sample
results indicated that concentrations of
metals and PAHs in the two areas did
not exceed regulatory criteria, and
additional planned sampling using Triad
methods was unnecessary.
The geophysical survey and soil-gas
sampling results were used to select five
[continued on page 6]
LEGEND
GPR Transect
Soil Borings (SWI)
Monitoring Wells (SWI)
orings (URS)
-------
Solid Waste and
Emergency Response
(5203P)
EPA 542-N-09-001
January 2009
Issue No. 40
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]
monitoring well locations on the landfill
perimeter for evaluation of flow
direction and potential release of
leachate into the river. The wells were
installed with 5-foot screens set at
depths to encompass historical high
and low ground-water levels. Only
arsenic was detected at concentrations
exceeding state regulatory criteria for
ground water in one (downgradient)
well, where concentrations reached 55.2
u.g/L (above the 50 u.g/L ADEC action
level). Remaining COCs were either
below state criteria or not detected in any
of the monitoring wells.
Results indicating VOC and methane
presence prompted collection of soil and
grain-size samples for future air
modeling. Soil-gas FID and PID data
indicated landfill methane concentrations
of 0-8,600 ppmv, while field GC analysis
found concentrations reaching 20,700
ppmv. Findings suggest future onsite
activities need to account for potential
methane concentrations above the lower
explosive limit (50,000 ppmv).
Project results indicated that FNSB could:
> Develop the auto impound and snow
piling areas without restrictions, and
> Employ soil-gas management strategies
such as subslab venting to prevent va-
por intrusion into onsite buildings.
The entire sampling program was
conducted in a single mobilization over
two months at a cost of approximately
$200,000, in contrast to a traditional site
investigation estimated at $300,000 over
five months.
Contributed by Tami Sheehan, FNSB,
(tsheehan(q),co.fairbanks. ak. us or
907-459-1240) and Kym Takasaki, U.S.
Army Corps of Engineers-Seattle District
fkym berly. c. takasaki(a)usace. army, mil
or 206-764-3322)
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welcomes readers' comments
and contributions. Address
correspondence to:
John Quander
Office of Superfund Remediation
and Technology Innovation
(5203P)
U.S. Environmental Protection Agency
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1200 Pennsylvania Ave, NW
Washington, DC 20460
Phone: 703-603-7198
Fax: 703-603-9135
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques and
technologies. The Agency does not endorse specific technology vendors.
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