United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102G)
EPA 542-N-00-001
February 2000
Issue No. 36
V-/EPA
CONTENTS
Field-Scale Testing of a
Composite Particle
Sediment Capping
Technology
Studies Conducted to
Determine Biological
Uptake from
Contaminated
Sediments
Phytoremediation Used
for Mining Sediments
Sediment Management
Work Group Addresses
Strategies
Newsletter on
Contaminated
Sediments Available
pagel
page 2
pages
page 4
page 4
The Applied Technologies
Newsletter for Superfund
Removals & Remedial
Actions & RCRA Corrective
Action
ABOUT THIS ISSUE
This issue highlights ongoing
field and laboratory
demonstrations concerning the
remediation of contaminated
sediments.
TECH TRENDS
Field-Scale Westing of a
Composite Particle
Sediment Capping
Technology
by John Hull, RE., Hull &
Associates, Inc., and Casey
Stephens, City of Toledo/Division of
Environmental Services
In September 1999, the City of Toledo
began conducting a long-term sediment
capping demonstration project on the
Ottawa River, which is a Lake Erie
tributary located in northwestern Ohio.
The project involves field-scale testing of
AquaBlok™, a composite aggregate
material consisting of clay minerals and
aggregate. AquaBlok was applied through
the water column to physically stabilize
and isolate sediments contaminated with
polychlorinated biphenyls (PCBs) and
other contaminants in a particular portion
of the river. The material hydrates and
forms a cohesive, low-permeability, and
erosion-resistant barrier between sediments
and the overlying aquatic ecosystem
(Figure 1). Early field monitoring results
indicate that the composite material was
applied successfully and is isolating PCB-
contaminated sediments effectively.
Three sediment caps of different design
were installed along a 2.5-acre section of
the river: a composite aggregate, exclu-
sively; a basal geogrid component overlain
by composite aggregate; and a geogrid
plus composite aggregate and surficial
stone layer. Target hydrated cap thick-
nesses range from approximately 5-6
inches for the first two cap designs and
approximately 5-8 inches for the design
incorporating a surficial stone layer.
Various installation techniques also were
demonstrated as part of the project.
Following geogrid installation from
workboats, approximately 364, 82, and 15
tons of composite aggregate were installed
using telescoping conveyor, helicopter,
and dragline delivery systems, respec-
tively. An additional 206 tons of
approximately one-inch stone then were
installed by the conveyor and helicopter to
finish construction of the stone-covered
cap. Spatial uniformity of capping
material applications was observed closely
during cap installation to ensure that an
adequate degree of coverage was achieved
through each of the application tech-
niques.
The adequacy of capping-material
applications was determined by collecting
bathymetric survey data at 297 points
along 13 cross-river transects. Post-
capping survey data were compared to
pre-capping data to determine net
elevational increases (estimated cap
thickness) across the project area. Survey
results indicated that good spatial
coverage was achieved and that con-
structed cap thicknesses generally fall
within respective targeted ranges for the
three different cap designs. Paver-bottom
core samples are being collected and
evaluated to more directly document
constructed cap thicknesses across
selected portions of the demonstration
area.
A baseline study of benthic invertebrate
organisms in the demonstration area was
conducted during the summer of 1999. A
follow-up study will be conducted during
the summer of 2000 to determine if
organisms have colonized the encapsu-
lated areas. Since benthic organisms
typically colonize only the upper few
inches of sediment, they should remain
isolated from contaminated sediments.
[continued on page 2]
Recycled/Recyclable
Printed with Soy/Canola Ink on paper that
contains at least 50% recycled fiber
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BEFORE
HYDRATION
[continued from
page 1]
The composite
particle system was
originally developed
in 1994 at the Fort
Richardson
Superfund site in
Alaska to address
waterfowl mortality
from contact with
white phosphorus-
contaminated
wetland sediments.
After a multi-year
testing and observa-
tion period, the use of
AquaBlok was
incorporated into the Fort Richardson
Record of Decision to cap contaminated
sediments in difficult-to-reach marsh areas
that cannot be addressed by other technolo-
gies.
Technical assistance and input at the
inception of the Ottawa River project was
provided by the Ohio EPA, U.S. EPA, and
U.S. Fish & Wildlife Service. The project
was funded in large part through a grant
from the Ohio Lake Erie Protection Fund.
Darin Lockert (Ohio Lake Erie Commis-
sion) may be contacted at 419-245-2778 for
additional information on the Fund. For
further information, contact Casey Stephens
(City of Toledo/Environmental Department)
at 419-936-3757 or
casey.stephens@ci.toledo.oh.us, or John
Hull (Hull & Associates, Inc.) at419-385-
2018 or jhull@hullinc.com.
Studies Conducted to
Determine Biological
Uptake from
Contaminated
Sediments
by Joseph Hughes, Ph.D., and
Mason Tomson, Ph.D., Rice
University/Department of
Environmental Science &
Engineering
Researchers at Rice University, Louisiana
State University, and Southern University at
Baton Rouge are studying the physical,
Figure 1. Composite Aggregate Capping Material
AFTER
HYDRATION/EXPANSION
Composite
Aggregate
I—Capping —I
Material
. Contaminated,
1 Sediment """
Substrate
[not to scale]
V
chemical, and biological mechanisms
governing contaminant release and
biological uptake from contaminated
sediments. Laboratory studies on
sediments from Dickinson Bayou in
Galveston County, TX, confirmed that
desorption-resistant contaminant is
available to degrading microorganisms.
Similar studies have been conducted by
these researchers on sediments from Bayou
Manchac, LA, Utica Harbor, NY, and Lake
Charles, LA. Most significantly, results
indicate that the presence of an inducing
substrate may enhance rates of
mineralization of sorbed contaminants,
whereby endpoints of degradation are
similar regardless of initial contaminant
concentration.
Researchers anticipate that these findings
may help to set soil or sediment quality
limits for regulatory
purposes or to
establish endpoints
(no-action levels)
for remediation
purposes. Findings
suggest that
sediments and soils
presently requiring
treatment could be
left untreated
without increasing
the risk to human
health or local
ecosystems (Figure
2). In addition,
modified clean-up
levels (such as
allowing 10 percent
of the contamination at a site to be left in
place) could reduce remediation costs by
50-75 percent and save several years in
remediation time.
This multi-university applied research
project, which is sponsored by the Southern
Hazardous Substance Research Center
(HSRC), involves studies in three distinct
areas of biological uptake in: (1) bacterial
microbes; (2) bioturbating worms, and (3)
wetland plants. In the bacterial microbe
studies, a naphthalene solution was applied
on the Dickinson Bayou sediments to
prepare two types of contaminated soil:
sediment with desorption-available
naphthalene and sediment with desorption-
resistant naphthalene. The rates of
naphthalene mineralization demonstrated
that despite the low aqueous concentration
of naphthalene used in this study,
biodgradation could be initiated and
sustained. Both high and low levels of
contamination were degraded rapidly to
similar levels by the introduced micro-
organisms. In addition, it was found that
the rate and extent of mineralization of
desorption-resistant naphthalene could be
increased by the addition of naphthalene
vapor.
Studies on bioturbating worms focus on
determining the degree to which the worms
redistribute organic carbon matter, thus
releasing polycyclic aromatic hydrocarbons
(PAHs) into overlying water and helping
aerobic bacteria to biodegrade PAHs
through soil aeration. These types of
[continued on page 3]
Figure 2. Potential Clean-Up Scenarios
S 10,000-
5 •
O o>
•I
as E
"5
OT
0.01
0.0001
0.01
Solution Phase Concentration (mg/L)
Observed by HSRC researchers
Predicted by current theory
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[continued from page 2]
worms are "conveyer-belt" feeders, mixing
soils by feeding at a depth and defecating
on the surface. Bioturbating worms were
introduced into beds containing known
quantities of contaminanted sediments and
constant water flow. The worm Limnodrilus
hoffmeisteri was found to rapidly accumu-
late contaminant at high concentrations,
but its metabolic processes of ingestion and
defecation reduced the overall level of
accumulation.
The third part of the study examines plant
enzyme systems, focusing on the rhizo-
sphere (the area near plant roots where
bacteria are active) and the litter layer
(where recently discarded carbon matter
accumulates). Herbaceous grasses and
woody plants common in wetlands were
introduced to samples containing radionu-
clide-contaminated organic sediment from
a U.S. Department of Defense site. Mea-
surements of contaminants in the soil and
plant roots, shoots, and leaves were taken to
determine how much desorption-resistant
material has been taken up and whether
contaminants are available and biode-
graded in the rhizosphere.
Researchers will continue to monitor
biological uptake studies such as this in
both laboratory and field environments
over the coming year. For additional
information, contact Dr. Joseph Hughes
(Rice University) at 713-348-5903 or
hughes@owlnet.rice.edu, or Dr. Mason
Tomson (Rice University) at 713-348-6048
or mtomson@rice.edu.
Phytoremediation Used
for Mining Sediments
by BradLittlepage, U.S. Bureau of
Reclamation, andDuane Johnson,
Ph.D., Colorado State University
Plot testing of phytoremediation in the
Leadville Mine Drainage Tunnel (LMDT)
at the Leadville Mining District receiving
mine drainage from the California Gulch
Superfund site in Colorado is leading to
potential full-scale implementation of the
system in 2001. The pilot project, which
was conducted from June-December 1999,
resulted in removal of 70 percent of the
HSRC Conference to Be Held in May
The Great Plains/Rocky Mountain Hazardous Substance Research Center (HSRC)
will sponsor 2000 Conference on Hazardous Waste Research in Denver, CO, on May
23-25, 2000. Additional information is available on the Internet at http://
www.engg.ksu.edu/HSRC/Conferences.html.
metal contaminants in ground water (with a
pH of 7.2) that presently drains from the
tunnel. The U.S. Bureau of Reclamation
(BOR), Colorado State University (CSU),
Leadville Institute of Science and Technol-
ogy (LIST), and U.S. EPA are cooperating in
this effort.
To initiate the project, BOR, CSU, and LIST
researchers collected and analyzed an array
of plant species native to the Leadville area
and placed them in the pilot hydroponics
system. Plant analysis indicated that
several species contained significant levels
of metals, and in fact, recoverable quantities
of zinc were found in the tissue ofAchillea
sp. In situ pilot testing began with the
installation of a six-foot trough in which
several species (ranging from mosses to
mint and marigolds) were placed. One
month of treatment by plants exposed to
incandescent lights reduced the total metals
content of ground water flowing through
the tunnel pilot system from 6,000 ug/L to
840 ug/L at the point of discharge.
EPA is working with BOR to begin
conducting a treatability study involving
phytoremediation and metal hydroxide
precipitation (the current system) to
remediate surface water at the California
Gulch Superfund site. It is estimated that
300,000 gallons of surface water will
require treatment annually. The
phytoremediation system could reduce the
volumes of mine drainage water (at pH 5.5
or higher) passing through the metal
hydroxide precipitation system, thus
allowing for increased volumes of the pH
1.8 surface water into the current system.
Researchers estimate that phytoremediation
in the tunnel could reduce the current flow
of water to the treatment plant (1,700-2,000
gallons per minute [gpm]) by 600-1,000
gpm. Flow reduction achieved through
phytoremediation would allow the metal
hydroxide system to treat surface waters
with total metals loadings as high as
1,000,000 ug/L. As a result, full-scale
operation of the systems should enable the
facility to meet EPA's national pollutant
discharge elimination system requirements.
The study's large-scale phytoremediation
system uses three plant species selected for
their capability in manganese, zinc, and
cadmium uptake. Plants placed in troughs
throughout the tunnel will be evaluated for
their potential to treat 600-1,000 gpm of
water; the volume of water the troughs are
capable of processing within fifty feet will
serve as a study model. Upon entering the
tunnel, ground water will flow through a
55-gallon heating barrel that will raise the
water temperature from 44°F to 50°F. Water
then will enter three drainage runs, each
containing four 50-foot troughs that will
treat the water consecutively. Each
treatment trough will contain distinct
sections of silica sand, a foam bridge, and a
vegetable-based gel. Mustard (Brassica
juncea), quinoa (Chenopodium quina), and
yarrow (Achillea lanulosa) will be planted
separately in each of three troughs per run,
while the fourth trough will be used for new
experimental species.
Monitoring will include the sampling of
each species, within each medium, at three-
week intervals over 10 collection dates to
determine maximum metal uptake levels.
In addition, discharge water will be
composite-sampled on a daily basis to
determine the impact of each species on
ground-water contaminant concentrations.
Within the 11,300 foot-long tunnel, an
additional 450 feet of accessible space is
available for testing, if needed. Electrical
power for the phytoremediation system
currently is obtained from the water
treatment plant, but a solar system will be
installed for full-scale operations to provide
heat, light, and electricity inside the tunnel.
This technology may be applied in other
remote mining areas requiring remediation.
Project partners anticipate that the LMDT
ultimately will be used for development of
[continued on page 4]
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[continued from page 3]
additional mining technologies, in situ
studies on metals recovery, and genetic
engineering of plants. The Leadville
Institute of Science and Technology (a
local non-profit organization focusing on
technology and economic needs of the
Leadville area) also is working with the
World Bank to develop practical
approaches and cost-effective technologies
such as this in third-world countries. For
additional information, contact Brad
Littlepage (U.S. Bureau of Reclamation) at
719-486-2035 or e-mail blittlepage@
gp.usbr.gov, or Frank Burcik (Water
Treatment and Decontamination
International) at 303-202-9324 or e-mail
wtdifb@juno.com.
Sediment Management
Work Group Addresses
Strategies
In 1998, private industry, trade associa-
tions, and government agencies formed the
Sediment Management Work Group
(SMWG) in an effort to advance risk-based,
scientifically sound approaches for
evaluation of sediment management
decisions. SMWG's primary objectives are
to collect, develop, analyze, and share
information on the effectiveness of sedi-
ment management, technologies, and
approaches. Information products devel-
oped by the SMWG (and available at
www.smwg.org) include a decision tree for
sediment management alternatives, a series
of sediments-related technical papers,
and a database on contaminated
sediments sites. For more information,
contact the Group's Coordinator, Steven
C. Nadeau (Honigman Miller Schwartz
and Cohn) at 313-465-7492 or e-mail
scn@honigman. com.
Newsletter on
Contaminated
Sediments Available
Contaminated Sediments News is
produced by the U.S. EPA's Office of
Water/Office of Science and Technology
(OST) to exchange information on
contaminated sediments. "CSNews"
provides extensive information on EPA
headquarters, regional, and laboratory
activities addressing contaminated
sediments, and updates readers with
announcements concerning related
resources such as training courses, Web
sites, and upcoming events. The
newsletter is available on the Internet at
http://www.epa.gov/OST/pc/csnews/or
by contacting OST at 202-260-9830.
1 Mention of trade
or commercial products does not
constitute
endorsement by
the
U.S.
Environmental Protection Agency.
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102G)
EPA 542-N-00-001
February 2000
Issue No. 36
WENDS
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