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Tl
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/A newsletter about soil, sediment, and ground-water characterization and remediation technologies
Issue 29
77?/'s /'ssMe o/Techno logy News and Trends highlights strategies and tools for characterizing
or monitoring remediation of sites with contaminated sediment and surface water bodies.
Addressing these sites often relies upon dynamic workplans that involve more efficient, cost-
effective, and practical methods for field work.
New Sampler Minimizes Disturbance During Sediment Collection
The U.S. EPA Office of Research and
Development (ORD) National Exposure
Research Laboratory (NERL) has developed
an innovative tool known as the
undisturbed surface sediment (USS)
sampler. The instrument is designed to
collect the upper 15 cm (6 in) of sediment in
layers as thin as 1 cm for laboratory
analysis. Recent field applications
demonstrate that the sampler can collect
thin layers of newly deposited sediment
without mixing surface and subsurface
layers, a problem commonly associated with
conventional sampling methods.
The USS sampler consists of a support
stand, core sampling device, and ballast
system (Figure 1). During deployment, the
sampler is lowered from a boat to the
sediment surface, where the support stand
is placed approximately 1 ft from target
sediment to minimize surface/sediment
interference. Within the core sampling
device, a top-and-clamp block secures a 4-
in-diameter core tube as it slides down and
up during sample collection. A nose piece
mounted at the lower end of the core tube
releases a core catcher that seals the tube
as it is withdrawn from sediment.
The sampler's ballast system contains a lift
shaft, lift shackle, and weight spindle
holding up to five 10-lb weights. Using
direct pressure or pounding (raising and
dropping weights over the shaft end), the
core sampling device is directed to the
target depth for tube penetration. A
hydraulic piston then extrudes the retrieved
core into a slicer block where the core is
immobilized. When the block contains the
desired sediment thickness ranging from 1
to 15 cm, the slicer blade is pulled
horizontally to isolate the sample within the
block's upper collection chamber for
subsequent processing.
Following laboratory and field tests, a
modified prototype of the sampler was
evaluated last summer at the U.S. Navy's
Space and Naval Warfare (SPAWAR)
Command Systems Center in San Diego, CA.
Studies were conducted in two well-
characterized sites at the mouths of Chollas
and Paleta Creeks near Point Loma. Sediment
at both sites contains aluminum and iron in
concentrations averaging 14,877 and 20,537
mg/kg, respectively, and low levels of
arsenic, chromium, copper, lead, mercury, and
zinc. Individual samples were collected as
close together as possible to minimize local
sediment variation.
The evaluation included performance
comparison against a conventional Ponar
grab sampler. The USS sampler was used to
sample three successive sediment layers (0-
3 cm, 3-6 cm, and 6-9 cm), while the Ponar
sampler was used to collect collocated
samples of only the upper (0-3 cm) layer.
Samples were analyzed at an offsite
laboratory for total organic carbon (TOC)
content, particle-size distribution, and
concentrations of heavy metals.
[continued on page 2]
March 2007
Contents
New Sampler
Minimizes Disturbance
During Sediment
Collection page 1
Combined Benthic
Test Determines Metal
and Organic Flux Rates
in Marine Sediment page 2
ELISAAddedto
Rapid Screening
Characterization
Toolbox
page3
Integrated Pore-Water
and Geophysical
Investigations
Streamline
Characterization of
Ground-Water
Discharges to
Surface Water
pageS
CLU-IN Resources
The U.S. EPA's CLU-IN web
site offers a range of information
regarding characterization,
monitoring, and remediation of
sediment-contaminated sites.
Visit http://cluin.org/char1 .cfm
to access a number of re-
sources including guidance on
reducing risk at sediment sites
and references on capping,
dredging, and monitored natural
recovery.
[continued on page 6]
Recycled/Recyclable
Printed with Soy/Canola Ink on paper that
contains at least 50% recycled fiber
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[continued from page 1]
Mean TOC concentrations in the Ponar-
collected upper layer were 60,520 and
45,240 mg/kg at the Chollas and Paleta
Creek sites, respectively. Mean TOC
concentrations in samples collected by
the USS sampler were significantly lower,
at 35,780 and 28,720 mg/kg, respectively.
The difference suggests that a higher
mollusk-shell content in the Ponar
samples, which can capture sediment
below the target interval, led to inclusion
of inorganic carbon upon shell
dissolution. USS sampler-derived data
also indicated that TOC concentrations
at Paleta Creek slightly decreased with
depth, to concentrations of 27,540 and
26,440 mg/kg in the 3 -6 and 6-9 cm layers,
respectively.
Heavy metal concentrations consistently
were an average 20% higher in surface
samples collected by the USS sampler than
by the Ponar sampler. For example, an
average lead concentration of 87 mg/kg
was identified at Paleta Creek using the
USS sampler, but Ponar-collected samples
showed a concentration of 73 mg/kg.
Differences may be attributed to
unavoidable dilution of the 0-3 cm layer
with the 3-6 cm layer materials in the
Ponar samples. During typical Ponar
sampling, the sample is placed into a
steel pan where it tends to spread; from
Figure 1. Clear
water above the
core sample held
in a USS sampler
illustrates that
minimal sample
disturbance
occurs during
sample
collection.
there, attempts are made to collect only
the top 3 cm of sediment but mixing easily
occurs.
Particle-size analysis led to similar
conclusions regarding the inability of
Ponar technology to isolate and collect
only the surface layer of sediment. At
Paleta Creek, the mean particle sizes of
USS samples from the 0-3, 3-6, and 6-9 cm
layers were 62, 51, and 93 |lm,
respectively, while the mean particle size
for Ponar upper-layer samples was
slightly higher, at 68 |lm. ORD will issue a
detailed report on this evaluation in early
2007. Results from an earlier field test of
the USS sampler are available in
Collection of Undisturbed Surface
Sediments: Sampler Design and Initial
Evaluation Testing [EPA/600/R-05/076]
online at http://www.epa. gov/nerlesd 1 /cmb/
pdf7USS_Sampler_FINAL_REPORT.pdf.
Contributed by Brian Schumacher, Ph.D.,
NERL (schumacher.brian(q),epa.gov or
702-798-2242), John Zimmerman,
NERL (zimmerman.johnh(a),epa.gov or
702-798-2385), Julia Capri, Eastern
Research Group (Julia. capri(q),erg. com
or 513-791-9405), and V. Elliott
Smith, Ph.D., ASCi Corporation
(esmiths&.comcast.net or
248-342-8744)
Combined Benthic Test Determines Metal and Organic Flux Rates in Marine Sediment
Contaminant flux rates from marine
sediment recently were measured at Bishop
Point in Pearl Harbor, HI, using the benthic
flux sampling device (BFSD) developed by
SPAWAR Systems Center (SSC)/San
Diego. Reductions in field time and costs
were achieved through simultaneous
measurement of both metal and organic
contaminants during 72-hour deployment
of the BFSD. These measurements were
compared to the results of previous Bishop
Point BFSD deployments focusing on
metals versus polycyclic aromatic
hydrocarbons (PAHs) and on different
occasions. Comparison showed very similar
quantitative and qualitative results.
The tests were conducted at the Navy's
Marine Diving and Salvage Unit 1 (MDSU-
1) facility of Bishop Point, near the mouth
of Pearl Harbor, to support ongoing cleanup
of this National Priorities List site. MDSU-1
is located near active industrial and Navy
operations employing numerous surface-
water vessels such as salvage and dive-
boats, research ships, and barges
periodically moved by tugboats. Surface
water in this area is generally clear and
approximately 25 feet deep. Sediment
comprises fine- to medium-grained sand.
The BFSD typically is deployed from a
davit-capable boat from which sampling,
data logging, and control functions
operate automatically according to
preprogrammed parameters. A chamber
within the device traps a volume of water
directly above the sediment/water
interface and automatically collects
[continued on page 3]
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[continued from page 2]
samples at various intervals (Figure 2).
The chamber is a bottomless box,
approximately 40 cm square and 18 cm
tall, with a capacity of approximately 30
liters. A sensor-triggered oxygen
injection system is housed in the BFSD
to sustain ambient dissolved oxygen
concentrations (± 1 mL/L) inside the
chamber.
For the combined contaminant-type
test, one ambient and 11 split samples
were collected from the chamber at
approximate 7-hour sampling intervals
using 100-mL Teflon bottles for metals
and 250-mL amber glass bottles for
PAHs. Collected samples immediately
passed through 40-micron glass-fiber
filters within the BFSD. After the typical
72-hour deployment, sample bottles
were retrieved, packaged, and sent to
an offsite laboratory. Ancillary data
also were collected through use of an
onboard conductivity, temperature, and
depth system. The BFSD was deployed
at a single location over three days, but
earlier applications indicate that a
complete turnaround (including
retrieval, decontamination, reloading,
and deployment) can be accomplished
in a single day.
These analytical results and ancillary
measurements, as well as data from the
earlier metals-only andPAH-only BFSD
deployments, were incorporated into a
time-series analysis that showed flux
rates for metals and PAHs behaved
similarly across both scenarios. Arsenic,
cadmium, lead, nickel, manganese, and
zinc consistently fluxed out of sediment
at rates ranging from 1.3 |lg/m2/day for
cadmium to 1,940 |lg/m2/day for
manganese, while copper fluxed into
sediment at a rate of 71.3 |lg/m2/day.
Slightly higher flux rates for metals were
identified through the combined
deployment than during metals-only testing.
With the exception of phenanthrene, all
measured PAHs fluxed out of the
sediment. The highest PAH flux rate
(19,696 ng/m2/day) was for fluoranthene,
followed by anthracene, acenaphthene,
and naphthalene. High concentrations of
heavier molecular weight PAHs such as
benzo(a)pyrene, benzo(k)flouranthene,
and chrysene also were identified.
Benzo(a)pyrene was detected in samples
collected during the combined testing but not
in the early PAH-only test.
BFSD deployment using this combinedmethod
for metals and organics was estimated to save
more than $ 10,000 and four field days when
compared to the cost of two separate
rounds of deployment. Applications at
Bishop Point and other sediment sites indicate
thatthe BFSD is suitable in aquatic near-
shore environments at depths up to 50
meters. The device may be used
effectively in coastal areas with steep
sediment gradients where pore-water
sampling is difficult. In addition to
evaluating contaminant diffusion, as
typically derived from pore-water
analysis, the device helps to determine
the direction and magnitude of
sediment/water interface gradients.
Final results of the Bishop Point tests,
which were conducted as a demonstration
under the U.S. Department of Defense
Environmental Security Technology
Certification Program, will be available
online this spring at http://www.estcp.org.
Contributed by Brad Davidson, SCC
(bradley.davidson(q)navy.mil or
619-553-2804)
ELISA Added to Rapid Screening Characterization Toolbox
The U.S. EPAandU.S. Army Corps of
Engineers, along with a team of
researchers from Battelle, ENVIRON,
University of Maryland-Baltimore, and
the U.S. Navy, are examining the fate
and transport of hydrophobic
contaminants below capped sediment
at the Wyckoff/Eagle Harbor Superfund
Site in Bainbridge, WA. The study
involves use of an in-field rapid
screening characterization (RSC) tool
known as enzyme-linked immunosorbent
assay (ELISA). Study results show that
ELISA effectively provides field
measurements of target contaminants,
facilitates real-time decisions regarding
sample locations, and reduces the
quantity of samples requiring detailed
and expensive analysis at offsite
laboratories.
[continued on page 4]
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Figure 3. Data correlations indicated
that ELISA RSC techniques could be
used effectively to determine contaminant
concentrations in Eagle Harbor
contaminated sediment and its cap.
[continued from page 3]
PAH compounds are the primary
contaminants of concern (COCs) at this
site due to the use of creosote during
past wood-preservation activities. A
high potential for vertical migration of
dissolved contaminants exists due to
the area's 10-foot tidal fluctuations and
a steep upward hydraulic gradient in
the underlying aquifer. Recent field
work focused on identifying and
measuring in-situ hydrodynamic forces
and contaminant migration in buried
sediment as well as the 3-foot-thick, 13-
acre cap in place since 2001.
60,000
ELISA uses antibodies and enzyme
conjugates to detect and quantify COCs.
In this immunoassay, an enzyme is
linked chemically to a COC molecule to
create a labeled COC reagent, or
conjugate. The COC-antibody or
enzyme-COC-antibody complex
attached to a test surface reflects the
sample's amount of COC. Enzyme on the
test surface catalyzes a color-change
reaction when solution is added to the
test surface, and the amount of color
inversely corresponds to the COC
concentration.
The recent fate and transport study
combined data from an earlier field
conductivity survey with onsite and
offsite chemical data from the sediment
cap and native sediment. The
information helped determine the
potential for vertical PAH migration in
the sediment cap as well as the relative
influences of ground-water upwelling
and tidal fluctuations on contaminant
transport. Conductivity surveys located
areas of potential fresh-water upwelling
into the marine surface water, which in
turn represented the greatest potential
10,000 -
10,000 20,000 30,000 40,000 50,000 60,000
RSC Results
for upward vertical pore-water migration
and indicated optimal locations for
sediment/cap core collection.
Thirteen 3-inch-diameter cores were
collected from the sediment cap and
native sediment within and outside of
ground-water upwelling areas. To
examine the full sediment/cap interface,
each core extended 1-3 feet beyond the
cap. Cap cores were sectioned into 32
intervals above the native sediment/cap
interface, and 2-4 intervals were collected
from native sediment.
ELISA was used to measure total PAH
(TPAH) concentrations in each of the
selected core segments, which helped
avoid costs for offsite laboratory
analysis of samples with non-detects.
Based on ELISA results, 26 core
segments from only 4 cores were selected
for offsite analysis to evaluate 34
individual PAHs, particle size
distribution, and TOC. Comparison of
TPAH concentrations identified from
ELISA RSC and TPAH concentrations
determined through laboratory gas
chromatography/mass spectrometry
methods showed an overall correlation
coefficient of 0.9 (Figure 3). For TPAH
concentrations less than 1 mg/kg, the
correlation coefficient was 0.7.
As a result, RSC data were used to
develop a reliable profile of TPAH
concentrations within the existing
sediment cap, and study costs could
be further reduced by the need for less
offsite laboratory analysis supporting
profile development. The RSC-based
profile will be integrated into ongoing
cap monitoring efforts and evaluation
of the cap's performance. Final results
for this project, which was funded by
the Strategic Environmental Research
and Development Program will be
available online later this year at
http://www.serdp.org.
Contributed by Marc Mills, Ph.D., U.S.
EPA ORD/National Risk Management
Research Laboratory
(mills.marc(a),epa.gov or 513-569-
7322), VictorMagar, Ph.D., ENVIRON
(vmagar&.environcorp.com or
312-731-2419), Bruce Sass, Ph.D.
Battelle (sassb(a)battelle.org or
614-424-6315), and Jim Leather,
SCC dim.leather&navy.mil or
619-553-6240)
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Integrated Pore-Water and Geophysical Investigations Streamline Characterization of
Ground-Water Discharges to Surface Water
The Michigan Department of
Environmental Quality (MDEQ) uses a site
characterization approach relying on
optimal use of sediment pore-water data
to delineate contaminant ground-water
plumes entering surface water bodies. The
approach combines plume delineation data
obtained through simple, miniature
piezometer-based pore-water sampling
with subsequent information collected
through conventional wells and advanced
geophysical techniques. This stepwise
process helps to define both horizontal
and vertical preferential flow pathways,
and subsequently to install additional
permanent wells for monitoring the
ground-water/surface-water interface at
critical locations and depths.
The approach was used last year to
investigate soil and ground-water
contamination at the site of Hoskins
Manufacturing, a former wire-manufacturing
facility in northeast Michigan. Over more
than 30 years, operations waste containing
tetrachloroethene (PCE), hexavalent
chromium (Cr+6), and spent pickling brine
had been released into an unlined lagoon
and smaller source areas. Resulting
seepage contaminated sandy vadose soil
extending to the water table and
contaminated a drinking-water aquifer
prior to its discharge into a nearby cold-
water creek, which ultimately drains into
Lake Huron.
Pushpoint pore-water tools were used to
conduct preliminary sampling beneath the
creek bottom in areas intersecting the
apparent plume. Once the horizontal extent
of the plume was determined, pushpoint
sampling continued over a two-day, high-
density effort to collect samples from
alluvial sediment along the creek and
throughout the floodplain in the vicinity
of the discharge, thus delineating the area
of plume expression. During sampling, field
measurement of water quality parameters
(pH, conductivity, dissolved oxygen,
temperature, and oxidation/reduction
potential) provided useful geochemical
information throughout the contaminant
discharge area. Pore-water tools also were
used to measure associated hydraulic
potential (potentiometric surface
elevation) at the sample locations, and to
help determine the thickness of local
vegetative mat and the extent of a sand/
gravel substrate underlying the study area.
Analytical results from an MDEQ mobile
laboratory indicated that some of the
plume's highest PCE and Cr+6
concentrations were found in the pore-
water samples. Offsite laboratory analysis
confirmed that the highest pore-water PCE
concentration (approximately 500 (Ig/L) and
Cr+6 concentration (7,360 |Ig/L) in valley
sediments were slightly higher than
concentrations in ground water collected
from deep upgradient monitoring wells.
These trends indicated that very little
attenuation of contaminants is occurring
during plume migration. Correlations in
pore-water concentrations of chromium
and chloride also confirmed earlier
indications that Cr+6 travels with the brine.
Overall results indicate that PCE, present
mainly in the upper part of the shallow
aquifer, primarily discharges directly into
the creek bottom or through the vegetative
mat prior to entering the creek. Cr+6 and
brine in the lower part of the shallow
aquifer, however, tend to discharge
through the creek bed or through the
vegetative mat on the creek's far side. Prior
to investigation, potential for contaminant
discharge through the vegetative mat was
considered minimal due to the mat's
anticipated low hydraulic conductivity.
Of the field parameters measured, specific
conductivity provided the best indication
of plume discharge. Increased electrical
conductance due to the brine provided an
easily recognizable marker of Cr+6 in the
floodplain. Areas of lowest temperature
generally contained the highest Cr+6 and
PCE concentrations, suggesting that
temperature may serve as an additional
indicator of ground-water discharge. Data
suggest that a discharge of about 5 L/s of
highly contaminated ground water mixes
with the creek water, resulting in low but
measurable concentrations of these
contaminants in the creek flow.
Once the plume discharge was defined,
several geophysical techniques were
used to characterize the aquifer and
identify preferential ground-water flow
pathways before installing additional
deep monitoring wells. These methods
included "SuperSting" resistivity/induced
polarization, seismic reflection, and
downhole gamma-ray and electromagnetic-
induction logging techniques. Vertical
aquifer sampling was used in concert with
sonic drilling to determine the optimum well
[continued on page 6]
Contact Us
Technology News and Trends
is on the NET!
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Technology News and Trends
welcomes readers' comments
and contributions. Address
correspondence to:
John Quander
Office of Superfund Remediation
and Technology Innovation
(5102P)
U.S. Environmental Protection Agency
Ariel Rios Building
1200 Pennsylvania Ave, NW
Washington, DC 20460
Phone:703-603-7198
Fax:703-603-9135
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Solid Waste and
Emergency Response
(5203P)
EPA 542-N-06-008
March 2007
Issue No. 29
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]
screen elevations, and continuous
coring during this process allowed visual
examination of the aquifer material.
Resulting geological profiles indicated a
complex, 500-foot-thick glacial layer of
fine to coarse sand with interbedded silt
and clay lenses. Using these profiles, six
400-foot monitoring wells were installed
parallel to the 0.7-mile route of plume
migration from the facility.
MDEQ estimates that costs for the entire
pore-water investigation totaled less than
$15,000. Although the project findings
determined that the plume discharges to
the creek and alluvial valley sediment,
additional spatial and vertical delineation
of glacial sediment is required to fully
delineate the upgradient portion of the
plume before remediation planning
begins. Access to the valley bottom with
conventional equipment is difficult.
Consequently, plume movement and
stability will be monitored through the
use of permanent miniature wells to be
installed at shallow depths in the
floodplain discharge area. A
macroinvertebrate investigation also will
be conducted this year to evaluate
contaminant impacts on the aquatic
community.
Contributed by Mark Henry,
MDEQ, (henryma(a),michigan.gov
or 517-335-3390)
CLU-IN Resources
[continued from page 1]
CLU-IN's Measuring and Monitor-
ing for the 21 ^ Century webpage
features a technology focus area
on sediment sampling. Several
sediment samplers are described
along with a summary of typical
conditions under which they are
best suited. The information
provided can help investigators
select a sampler to use.
Visit CLU-IN at http://
www.cluin.org/programs/21 m2/
sediment/.
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques an
technologies. The Agency does not endorse specific technology vendors.
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