SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM SEDIMENTS REMEDIATION ACTION TEAM MEETING
National Oceanic and Atmospheric Administration
Building 9, Conference Room A & B
Sand Point, Seattle, Washington
January 24-25, 2001
WELCOME AND OPENING REMARKS
John Davis, The Dow Chemical Company
John Davis opened the meeting by welcoming participants. (Attachment
A lists the meeting attendees.) He said the objective of the meeting was
to identify potential new collaborative programs for Remediation Technologies
Development Forum (RTDF) subgroups to initiate in the area of monitored natural
recovery (MNR) of sediments. After a series of presentations on different aspects
of natural recovery, Davis said, the group would hold a roundtable discussion
to brainstorm on ways to move this clean up option forward.
OVERVIEW OF MONITORED NATURAL RECOVERY
John Davis, The Dow Chemical Company
Davis defined MNR as a remedial option that relies on natural
environmental processes to permanently reduce the risk of contaminated sediments.
(His presentation materials are included as Attachment
B.) These natural processes include sediment
deposition or burial, chemical and biological reactions, contaminant dispersion,
and irreversible adsorption. MNR is different from "no further action" because
it requires monitoring, assessment, and modeling.
Davis emphasized that researchers
need to obtain a thorough understanding of the natural processes that affect
the fate, mobility, and availability of contaminants. If these processes are
understood, MNR could be used more often to manage contaminated sediments. Davis
provided examples of physical, chemical, and biological processes that, as part
of MNR, reduce the mobility of sediments and limit the flux of contaminants
out of sediment. Physical processes are dependent on hydraulic characteristics
that limit resuspension and transport of sediments and minimize contaminant
mobility. Chemical binding processes, Davis said, limit contaminant bioavailability
by causing contaminants to adhere to organic fractions of sediment. Biological
processes that impact a contaminant's fate include bioturbation and microbial
activity.
Factors that reduce the effectiveness
of MNR, Davis said, include ongoing contamination, insufficient deposition of
clean sediments, high-energy environments in which sediments are constantly
resuspended or transported, low organic content of sediments (which prevents
binding of some hydrophobic compounds), and microbial processes that transform
contaminants into a more soluble or bioavailable form. Because of these factors,
MNR as a long-term remedial solution might not be appropriate for every site.
Davis said that some Sediments Remediation
Action Team members worked together to create a paper on MNR. This paper lists
a series of tools that can be used to measure sediment contamination, measure
contaminant transport, and quantify natural recovery mechanisms. Davis noted
that there is a need to identify accurate and relevant indicators of the effectiveness
of MNR, and to quantify the rates, trends, and permanence of natural recovery
mechanisms. He suggested using measurements of physical transport, contaminant
weathering, and ecosystem impacts or recovery.
Davis said that models strive to
explain past history and predict future performance. Models should be used to
assess MNR and can examine sedimentation rates, contaminant sources, sediment
transport, and bioaccumulation. Davis stressed, however, that modeling should
never take the place of measurement if the latter is possible.
Math models can be used to describe
and predict sediment transport and build upon more basic models: for example,
hydraulic models that describe flows and associated stresses. Conceptual models
can be used to conduct exposure pathway analyses and identify relevant ecological
receptors. Conceptual models completely describe a site, including contaminant
source areas and the physical, chemical, and biological processes affecting
contaminant transport.
Lastly, Davis said that he believed that the current process for applying monitored natural attenuation in ground water could be used as an overall framework for implementing MNR in sediments. The steps could include the following:
EVALUATION OF TOOLS FOR NATURAL RECOVERY
OF SEDIMENTS: FIELD STUDIES
Victor Magar, Battelle Memorial
Institute
Victor Magar discussed the results of a field
study at Lake Hartwell in South Carolina that examined natural capping and weathering
processes. (His presentation materials are unavailable at this time.)
The U.S. Environmental Protection Agency (EPA) requested the study to identify
a snapshot evaluation technique for determining how natural recovery is working
at a site. A snapshot approach has value because it can characterize natural
recovery more quickly than other methods. The method used at this site took
about a year to complete, including the quality assurance plan, sampling, analysis,
and report.
Lake Hartwell is a reservoir that has been contaminated
by a single source of polychlorinated biphenyls (PCBs). The PCBs emitted by
the source included variants 1016, 1242, and 1254. The public and the entity
responsible for the contamination both identified MNR as the preferred remedial
choice.
For MNR to work effectively, Magar said, there
needs to be net deposition, in which clean sediments are being deposited on
top of contaminated sediments to produce a natural cap. This natural capping
requires source control, and should be considered the primary protective measure.
Weathering processes can reduce risk further.
The study examined the history of PCB deposition
and dechlorination at Lake Hartwell as a way to measure the extent of natural
capping and weathering processes, respectively. To examine these processes,
Magar used a snapshot evaluation technique that involved coring sediments. This
technique allows researchers to trace the history of contamination and natural
recovery processes at a site by viewing and analyzing vertical profiles of sediment.
In this study, Magar collected 10 sediment cores throughout the lake and divided
each core in 5-centimeter increments from the sediment-water interface to the
bottom of the core. Then, Magar analyzed each increment for PCBs, lead-210,
and cesium-237. PCBs were separated out into 107 congeners. The analyses of
lead-210 and cesium-237 helped date the sediments.
Magar discussed the results of the study. With
regard to the history of PCB deposition, he pointed out that, in one of the
cores, the highest PCB concentrations were strongly associated with silt layers
and the upper sand layers had very low concentrations (e.g., less than
1 milligram per kilogram, or mg/kg). At Lake Hartwell, where the regulatory
PCB limits are 1 mg/kg, there is a good barrier of about 70 centimeters of sand
that provides a natural cap. In another core, Magar was able to trace the entire
history of PCB contamination in the lake. At the bottom of the core were very
low concentrations. PCB concentrations increased gradually from the bottom of
the core through the middle, which correlated with increased PCB releases from
the plant. From the middle of the core to the top, steady decreases in PCB concentrations
were found, which correlated with the closing of the PCB source in the 1970s.
Using sediment age-dating analysis, Magar determined
the sediment accumulation rates for different areas of the lake. He found the
average rate at the surface to be about 5 centimeters per year. Using the sediment
accumulation rates, Magar estimated how much time it would take to reach various
regulatory goals for Lake Hartwell, including the goal of the site's record
of decision (1 mg/kg for PCBs in surficial sediment) and the mean site-specific
sediment quality criteria developed by EPA in 1984 (0.4 mg/kg). He estimated
it would take 1 to 5 years for enough sediment deposition to reach the 1 mg/kg
goal and 2 to 10 years to reach the 0.4 mg/kg goal.
To investigate the history of PCB dechlorination,
Magar compared the levels of chlorination and PCB characteristics between a
surface sediment sample and a deeper sample. By determining the amounts of different
PCB congeners in the different sediment samples, he found that dechlorination
was higher in the deeper sample. Specifically, there were more PCB congeners
with only one, two, or three chlorines in the deeper sample; in the surface
sample, PCB congeners tended to have four or five chlorines. In addition, the
PCBs in the deeper sample had more chlorines in the -ortho positions rather
than the -meta and -para positions. These dechlorination characteristics indicate
that the deeper sediments were becoming less toxic over time. Magar also showed
that these characteristics were not unique to these two samples. (Answering
a question posed by the audience, Magar said that he was not sure if dechlorination
would ever occur at the surface.)
Magar also described another PCB dechlorination
analysis--polytopic vector analysis--that identified PCB end members and measured
their concentrations in the sediment. Using polytopic vector analysis, Magar
identified three end members: a mixture of PCBs 1248 and 1254, the dechlorination
byproduct of PCB 1248, and an intermediate product between the first and second
end members. End member one was found in highest concentration in the surface
sediment and decreased with depth; the second and third end members increased
with depth. This follows the pattern found in the first dechlorination analysis:
PCBs are becoming less chlorinated, and therefore less toxic, over time.
The snapshot method cost $250,000 to complete.
Magar believed it was successful. He noted, however, that this assessment would
need to be integrated with modeling and studies of the benthic zone to determine
fish recovery rates and future risk of resuspension of sediments.
USING NATURAL PROCESSES TO DEFINE EXPOSURE
FROM SEDIMENTS
Danny Reible, Louisiana State
University
Danny Reible began his presentation by stating
that one should conduct a site-specific analysis of natural processes before
selecting a management option. (His presentation materials are included
as Attachment C.)
This is because natural processes always influence the attenuation or accessibility
of contaminants in sediments; depending on the site, different natural processes
will have more of an impact than others.
The amount of risk, Reible said, depends on actual
or potential contaminant exposure in the biologically active zone of sediments.
Fish and higher animals can be exposed directly to contaminants released by
resuspended sediments or from the bed sediment to the overlying water, and from
incidental ingestion of bed sediments. They can also be exposed indirectly by
eating other animals or plants that live in the contaminated sediment.
Reible said that natural processes have the greatest
influence on risk in areas targeted for MNR or in situ management,
in areas outside the zone of active remediation, and in areas where residual
contamination remains after active remediation has taken place. These natural
processes include sediment movement, bioturbation due to the normal life-cycle
activities of benthic organisms, surface- and ground-water interactions, and
gas seepage through the sediment. The relative importance of particular processes
depends on the type of aquatic environment (e.g., lacustrine versus
estuarine).
To characterize these processes, Reible said, a number of measurements can be used:
These measurements
can be interpreted directly or through a model. Researchers can use a model
to predict future results and assess the sensitivity of the system to different
factors. This type of information cannot be obtained directly from measurements.
Reible said that sediment environments can be
understood as either dynamic or stable. In a dynamic environment, contaminants
are strongly associated with solids; therefore, contaminant dynamics are defined
by sediment dynamics. Natural processes in dynamic environments should be appreciated.
Some seemingly stable environments are actually dynamic. For example, although
historically contaminated sediments are often associated with net depositional
environments, it is important to realize that the sediment environment may have
been dynamic in the past due to the removal of dams or the effect of capping.
Capping can change the equilibrium surface of the bed and its depositional character,
which can create a scouring situation. Stable environments can also become dynamic
due to episodic erosional events.
Reible noted one exception about dynamic environments:
when, in such environments, contaminants are released to the overlying water
column, contaminants may not be as strongly associated with particulate matter,
due to the lower concentration of solids.
In stable sediment environments, particle movement does not control contaminant movement. Instead, the natural processes that affect contaminant movement are:
In most stable sediment environments (at least
those with large benthic communities), bioturbation largely controls contaminant
movement and fate in the upper layers of the sediment. Bioturbation increases
sediment cycling to the surface, pore water irrigation of sediments, and oxygen
transport to the sediments (which increases microbial degradation of contaminants).
Reible said that researchers have developed measurements and models to determine the bioavailability of contaminants such as metals and hydrophobic organic contaminants (HOCs), but more work is needed in this area. In addition, Reible listed a number of other research areas that need to be explored to obtain a better understanding of natural processes and how they affect risk. These research needs are summarized in the following table:
| Research Area | Specific Needs |
|---|---|
| Assessing Sediment Processes | There are critical problems of spatial and temporal variability--the current models make crude
assumptions about variation of sediment and water quality.
There is a need to characterize incoming sediment loads. |
| Assessing Contaminant Processes | Research is needed on hydrophobic contaminant release from sediments by mechanisms other
than particle release.
|
| Metals Release and Availability | How do we apply research tools to the field?
|
| HOC Release and Availability | Is desorption of HOC bimodal, or is it linear and reversible?
|
| Biological Processes and Effects | Researchers need to better understand diagenesis and its relation to metals speciation.
|
| Ecological Risk Modeling | Researchers need to expand risk assessments to entire ecosystem--almost all assessments are
based on individual-level endpoints, which is insufficient except for endangered species.
|
NEW
APPROACHES TO STUDYING SEDIMENT TRANSPORT
Patrick McLaren, GeoSea Consulting,
Ltd.
Patrick McLaren described his sediment transport
analysis (STA) technique, which can be used to explain how a site's environment
is working and inform decisions about that site. (His presentation materials
are included as Attachment
D.) For example, by defining transport pathways
for contaminants at a site, STA can show the areas in which monitoring would
be most useful. However, McLaren said, STA does not give the rates or amounts
of sediment deposition, so it cannot show, for example, whether natural capping
would be fast enough to serve as an effective remedial action.
STA can be used to determine the net sediment
transport pathways in any sedimentary environment. These pathways determine
the dynamic behavior of the bottom sediments (e.g., net erosion, net
accretion, or dynamic equilibrium), which in turn can help predict contaminant
dynamics. Net erosion means more particles are leaving than coming in, resulting
in rapid contaminant dispersal down the transport pathway. Net accretion, on
the other hand, creates a buildup of contaminants along the transport pathway,
making it difficult to determine the contaminant source. In dynamic equilibrium,
there is an equal probability of a particle leaving or arriving to the sediment
bed. STA can pinpoint areas of total deposition, which often are "hot spots"
of contamination.
To carry out STA, McLaren said, one must understand
the complete grain size distributions of bottom sediments. One obtains these
data by collecting samples over the area of interest in a regular grid. The
data are then interpreted using techniques supported by McLaren's theory paper
(see http://www.geosea.ca). Generally, the technique involves finding subtle
but statistically significant changes in grain size distributions that follow
the rules of transport. The results of an STA are usually mapped.
McLaren explained how he used STA to help the
U.S. Navy decide whether to remediate Dyes Inlet in Puget Sound, Washington.
By completing an STA for the site, he was able to determine that present "hot
spots" were not moving anywhere, incoming sediments were arriving from far away
and might be contaminated, and contamination levels throughout the inlet were
about equal. As a result, the stakeholders agreed that remediation could only
be implemented after the toxicity of depositing sediments decreased.
In another example (from Victoria Harbor, British
Columbia), McLaren showed how STA can be used to divide a site into separate
transport environments. As a result of this STA, he determined that contaminants
from offshore sewage outfalls were not affecting the coast or harbor, and that
each of the basins inside the harbor would likely contain a "hot spot" showing
unique contaminant characteristics. This information helped the owners of the
site choose effective remediation options and monitoring locations.
McLaren also discussed the results of an STA he
completed for the Anacostia River in Washington, D.C. He used the STA to determine
the types of sediment in the river and their dynamic behavior, and to predict
"hot spots."
McLaren explained the main advantages of STA:
ROLE OF MODELING IN ASSESSING NATURAL
RECOVERY
Mike Erickson and Greg Peterson,
Limno-Tech, Inc.
Mike Erickson first presented an overview of natural
recovery, then spoke about the role of modeling in assessing natural recovery.
(His presentation materials are included as Attachment
E.) Risk-based assessments, he said, are used
to determine the benefit of using natural recovery as a remedial option. These
assessments can have many objectives, including examining ongoing loading and
its effects on observed recovery rates and determining the potential for recontamination
from active remediation efforts. Risk-based assessments might not be needed
at sites that only have small, localized "hot spots," but are very important
for sites with broad-scale low-level contamination that would require long remediation
times.
Modeling is often used to complete risk-based assessments. Models can:
The time factor influences the comparison of natural
recovery's benefits to active remediation's benefits. For this comparison to
be realistic, the models should have realistic assumptions built in, such as
the long implementation times and costs for remediating large sites. Erickson
illustrated this point with a graph that demonstrated that, as a remedial target
is approached, uncertainty increases about whether active remediation will provide
enough benefits. For sites with long implementation times, natural recovery
can achieve comparable results to active remediation.
Erickson provided some background on models and their broader uses. Models can be used to:
Two types of models are commonly used to assess
natural recovery: fate and transport models and bed stability models. Fate and
transport models combine the effects of natural processes, contaminant loadings,
and loading trends to reproduce observed trends. For example, when there have
been significant declines in loads at a site and there is a need to predict
future processes based on loading trends observed in the past, a fate and transport
model can superimpose contaminant loading trends on trends due to natural processes.
This type of model can determine the importance of loading. After using fate
and transport models to drive exposure calculations for a long-term risk assessment,
one can apply stand-alone stability models and use them to address the question
of permanence. Erickson provided some examples of stability calculations that
determined the possibility of significant wind scour and flood-induced scour
at two sites.
Models try to integrate all active-layer natural
processes: resuspension, deposition, partitioning between the water column and
surface sediment or the pore water and sediment particles, dissolved-phase mass
transfer of contaminants in pore water, ground-water seepage infiltration, particle
mixing, contaminant decay and net burial, or scour.
Models need to be calibrated to the observed natural
recovery rates at a site. A model's ability to predict future contaminant declines
depends on how well it is calibrated. Once models are calibrated and include
accepted values for process coefficients based on the existing body of literature,
the models can be used to separate out the impacts of particular contributing
factors, such as burial. Models cannot predict rates without site-specific data:
they are highly sensitive to coefficients that are hard to measure, even within
a site.
Simple models can be used to determine contaminant
declines arising from individual or multiple natural processes such as burial
in depositional zones, contaminant decay, groundwater infiltration, pore water
mass transfer, and resuspension/deposition. Such a model includes a simple rate
calculation: characteristic velocity divided by mixed depth.
State-of-the-art model frameworks currently being
used to evaluate remedial alternatives typically include hydrodynamic and sediment
transport models linked to contaminant fate models and bioaccumulation models,
which are calibrated to observed site behavior.
Erickson stressed the importance of developing
a model that meets the needs of all stakeholders. He advised breaking down a
model into separate components and reaching agreement on the data needed for
each component. He also said that a model can only address the particular questions
for which it is designed.
Erickson also noted an important concern with
the design of monitoring programs. Site monitoring should consider the significant
additional value that can be added to measurements of contaminant concentrations
by spending the small additional effort to collect basic environmental information
and conventional monitoring parameters. When designing data collection programs,
it is important to consider the range of likely uses of the data and to recognize
opportunities to leverage project resources by ensuring necessary data are collected
early on. These additional data will often determine the utility of an expensive
contaminant monitoring data set to be used for basic system analysis, such as
transport calculations.
He said that current modeling development needs for the use of models in evaluating natural recovery include:
THE ROLE OF ECOLOGICAL MODELING IN ASSESSING
NATURAL RECOVERY OF SEDIMENTS
Rob Pastorok, Exponent Environmental
Group
Rob Pastorok opened his presentation by defining ecological models: they assess risks posed to particular populations (e.g., fish or benthic invertebrates) by looking at the interactions between different species and abiotic processes. (His presentation materials are included as Attachment F.) To accomplish this, the models support the definition of recovery targets and can be used to interpret monitoring data. Specifically, the models can be used to:
Pastorok said that ecological endpoints are used
to monitor natural recovery. Endpoints should be measurable and understandable
to scientists, environmental managers, and lay people. The selection of these
endpoints depends not only on the ecological structure and dynamics of benthic
communities (e.g., macroinvertebrates, fish, aquatic vegetation) but
also on non-ecological issues such as statistics, stakeholder interest, and
regulatory policy. Three commonly used ecological endpoints are population abundance,
the distribution of organisms in space and time, and species richness (a measure
of the number of taxa, or types of organisms present). When direct measurements
are not possible, an ecological model can be used to extrapolate the effects
on these endpoints. Such a model uses toxicity tests and empirical relationships
between the measurements and endpoints. Using scientific, political, and economic
criteria, Pastorok has determined that endpoints at the population and metapopulation
levels were most tractable and ecologically relevant.
Ecological models are not just exposure models,
Pastorok said, noting that they can also be used to track the abundance and
persistence of particular species within a community as a result of species
interactions such as predation or competition. There are four types of ecological
models: population models, ecosystem models, landscape models, and toxicity
extrapolations.
When defining recovery targets at the population
level, the mean and variance of each recovery endpoint needs to be defined,
the targets must be similar to the reference area, and the temporal and spatial
dynamics of the system must be considered. Pastorok gave a number of examples
that emphasized the importance of natural variability in biological systems.
To analyze monitoring data using ecological models,
Pastorok said, researchers need univariate or multivariate statistical analyses
to evaluate trends and determine if recovery targets have been met. Indices
and ratios should be avoided, since they might lead to statistical artifacts.
Ecological models range from simple to complex.
Pastorok cited a 1997 study by Kolak et al. that used the logistic
model, a simple population growth model, as the basis for determining the recovery
rate of the burrowing mayfly (Hexgenia) in Lake Erie. Pastorok also
cited more complex models. Generally, as the trophic level (i.e., predators
versus prey) increases, the complexity of the ecological model increases
as well. Ecosystem models representing food webs and abiotic processes might
be made up of several types of models--again, with more complex models at higher
trophic levels.
Pastorok listed his conclusions on the status of ecological models:
Pastorok assured audience members that the literature
contains data that define growth rates for different species, as well as other
factors (like predation levels) that affect population size. When necessary,
he said, the data can be obtained in the field rather quickly and used to compare
remedial alternatives, at least on a relative scale. Steve Ells emphasized that
models of complex ecosystems should be used to direct sampling programs that
assess natural recovery. Dick Jensen asked if there were any acceptable methods
for manipulating ecosystems to achieve natural recovery goals more quickly.
The group discussed particle broadcasting and seeding benthic communities as
potential methods, but Ells reminded the group of the danger of introducing
invasive species (e.g., zebra mussels) and the question of whether
the change in the ecosystem is a sustainable one.
DISCUSSION AND BRAINSTORMING SESSION
John Davis asked the group to brainstorm on how
the RTDF could move the science of natural recovery forward. To initiate the
discussion, Davis summarized the presentations and reviewed the main questions
that were discussed in each presentation.
Evaluation of Tools for Natural Recovery,
Victor Magar
Magar, in his study, tried to determine the type of data collection that could provide a snapshot of the effect of natural processes on contaminants over time. After his presentation, a number of questions were asked, including:
Davis suggested reviewing Jensen's capping proposal
for the Anacostia River to determine whether research on natural recovery assessment
could be incorporated into the proposal. Dick Jensen, Paul Mudroch, and Victor
Magar volunteered to work with Davis to investigate a possible MNR field project
at the site.
New Approaches to Studying Sediment Transport,
Patrick McLaren
After Davis summarized the main points from McLaren's
presentation, Clay Patmont mentioned that natural recovery projects are ongoing
in Puget Sound. At some of these sites, as much as 30 years of monitoring data
have been collected to track contaminants in sediment and biota. No one has
analyzed the data yet because the information is scattered among various agencies
and individuals. Patmont thought the RTDF could help evaluate the data and assess
the effectiveness of natural recovery at some of these sites. The RTDF would
be a good group for this analysis: it can be considered unbiased, with both
industry and government interests represented. This type of assessment would
have great value in helping others to make decisions about the use of natural
recovery. Patmont suggested confining the evaluation to sites that have gone
through a regulatory-approved process since data collected from these sites
would be quality assured and peer reviewed.
Magar pointed out that the RTDF could also make
use of monitoring data from other Puget Sound sites where natural recovery was
not the chosen remedial option. For example, if someone monitored benthic community
recovery at a cap site, that data would still be valuable.
Steve Ells mentioned that a similar project is
ongoing under Superfund; data are being generated in a form that might be useful
to the group.
As a result of the discussion, Mike Swindoll,
John Davis, Steve Ells, Ralph Stahl, Paul Mudroch, Victor Magar, Steven Brown,
and Greg Peterson agreed to work with Patmont on reviewing contaminated sediments
natural recovery projects.
Role of Modeling in Assessing Natural Recovery,
Michael Erickson
After looking at multiple sites, Davis noted,
Limno-Tech, Inc., concluded that the half-life for PCBs ranged from between
5 and 15 years across the board. Erickson confirmed this, but noted that the
half-lives cited are for PCBs in surficial sediment. Magar noted that PCBs buried
deeper in the sediment might disappear more slowly via dechlorination processes.
Davis said that another important point was expressed
during Erickson's presentation: investigators whoare
conducting monitoring must be aware of the types of data needed to support modeling
efforts.
Erickson agreed to work with Davis on a paper on
the role of ecological modeling and data needs for evaluating natural recovery
of sediments.
Using Natural Recovery to Define Exposure
from Sediments
Davis noted that Reible brought up two interesting questions during his presentation:
In addition, noted Davis, Reible listed many research
needs (see page 6). Davis asked Reible to help the group set priorities for
the research needs.
With regard to metal release and availability,
Reible said, the main obstacle is being able to predict and use a model. Steve
Ells said the source of these problems has to do with surface interaction, and
that a model should not have to rely on kinetics to make accurate predictions.
Instead, Ells believed that with a better understanding of surface interaction,
along with inorganic-organic and biological interactions, metal release and
availability could be described in a pseudo-equilibrium way.
To help get at the question of metal release and
availability, Reible said, metal concentrations in pore water must be measured
and redox effects on metal migration must be understood. For example, Reible
said, if erosion or dredging causes sediments to be resuspended, researchers
will need to know how much metal will change its state to a more bioavailable
form and become introduced into the pore water. In other words, will the sediment
resettle before having a chance to release metals to the overlying water? Currently,
there is no way to measure these redox effects. Reible pointed out that the
redox question has not been answered yet for any type of contaminant. He concluded
that a conceptual model needs to be developed for chemical fluxes at the sediment
interface before research needs for metals can be prioritized.
With regard to HOC release and availability, Reible
said, it is recognized that a significant fraction of HOCs do not desorb to
the extent or rate expected. The implication of this fact on uptake and biota
effects is not known, Reible said, but he felt RTDF should be aware of it. In
terms of prioritizing research needs, Reible said it is most important to determine
how much HOC moves around by pore water processes and to study the importance
of HOC accumulation at bubble interfaces in areas of gas generation.
As for efforts to model sediment processes, Reible
said, it is most important to develop new models based on first principles (perhaps
using laboratory measurements to create them). Current contaminant transport
models use one coefficient to lump together a variety of sediment migration
processes. Reible said this was problematic since these models: (1) do not account
for individual mechanisms, and (2) assume constancy in the rate of particular
processes such as bioturbation. To resolve this, Reible suggested developing
a conceptual model of the natural processes that cause contaminant migration
even without sediment movement. This model could make use of high-resolution
cores and could incorporate various modules that describe individual mechanisms
separately. Erickson noted that they are working on a model like this, but a
significant issue is the problem of seasonal variability in contaminant transfer.
He believed this is an important area to research in further detail.
ACTION ITEMS
RTDF
Sediment Remediation Action Team
Meeting
National
Oceanic & Atmospheric Administration (NOAA)
Building 9, Conference Room A & B
Sand Point, Seattle, Washington
January 24-25, 2001
Final Attendee List
Ben Baker
Remediation Leader
The Dow Chemical Company
Ashman Center
9008 Building - 4520 East Ashman
Midland, MI 48674
517-636-0787
Fax: 517-636-1364
E-mail: bbaker@dow.com
Bill Batchelor
Professor
Civil Engineering
Texas A&M University
3136 TAMU
College Station, TX 77843-3136
409-845-1304
Fax: 409-862-1542
E-mail: bill-batchelor@tamu.edu
Gary Bigham
Exponent Environmental Group
15375 Southeast 30th Place - Suite 250
Bellevue, WA 98007
425-643-9803
Fax: 425-643-9827
E-mail: bighamg@exponent.com
Steven Brown
Senior Scientist
Toxicology
Rohm and Haas Company
727 Norristown Road
P.O. Box 904
Spring House, PA 19477
215-639-5323
Fax: 215-619-1621
E-mail: rahssb@rohmhaas.com
Shari Brown
Environmental Manager
Weyerhaeuser
P.O. Box 9777 (CH 1L28)
Federal Way, WA 98063-9777
253-924-2729
Fax: 253-924-2013
E-mail: shari.brown@weyerhaeuser.com
Michael Buchman
National Oceanic & Atmospheric Administration
7600 Sandpoint Way, NE
Seattle, WA 98115
206-526-6340
Fax: 206-526-6865
E-mail: mfb@hazmat.noaa.gov
Scott Cieniawski
Environmental Engineer
Great Lakes National Program Office
U.S. Environmental Protection Agency
77 West Jackson Boulevard (G-17J)
Chicago, IL 60604
312-353-9184
Fax: 312-353-2018
E-mail: cieniawski.scott@epa.gov
Catherine Creber
Remediation Leader
Dow Chemical
1425 Vidal Street, S - Building 116
Sarnia, Ontario N7T 8C6
Canada
519-339-5004
Fax: 519-339-3912
E-mail: ccreber@dow.com
John Davis
Research Leader
The Dow Chemical Company
Building 1803
Midland, MI 48674
517-636-8887
Fax: 517-638-9863
E-mail: jwdavis@dow.com
Nicholas Di Nardo
Remedial Project Manager
Federal Facilities Branch
Hazardous Waste Management Division
U.S. Environmental Protection Agency
1650 Arch Street (3HS50)
Philadelphia, PA 19103-2029
215-814-3365
Fax: 215-814-3051
E-mail: dinardo.nicholas@epa.gov
Steve Ells
Sediment Team Leader
Office of Emergency & Remedial Response
U.S. Environmental Protection Agency
Ariel Rios Building (5204G)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
703-603-8822
Fax: 703-603-9100
E-mail: ells.steve@epa.gov
Michael Erickson
Senior Project Engineer
Limno-Tech, Inc.
501 Avis Drive - Suite 1
Ann Arbor, MI 48109
734-332-1200
Fax: 734-332-1212
E-mail: merickson@limno.com
Kenneth Finkelstein
Environmental Scientist
National Oceanic & Atmospheric Administration
c/o EPA Office of Site Remediation & Restoration
J.F.K. Federal Building (HI0)
1 Congress Street - Suite 1100
Boston, MA 02114-2023
617-908-1499
Fax: 617-918-1291
E-mail: ken.finkelstein@noaa.gov
Clifford Firstenberg
Firstenberg Consulting LLC
16 Ensigne Spence
Williamsburg, VA 23185
757-258-7720
Fax: 757-258-7721
E-mail: clifford.firstenberg@verizon.net
Katherine Fogarty
Senior Environmental Scientist
Menzie-Cura & Associates, Inc.
One Courthouse Lane - Suite 2
Chelmsford, MA 01824
978-322-2815
Fax: 978-453-7260
E-mail: kafogart@menziecura.com
Skip Fox
Project Manager
Boeing Environmental Affairs
P.O. Box 3707 - Mail Stop 7A-WW
Seattle, WA 98124-2207
425-865-6465
Fax: 425-865-6608
E-mail: skip.fox@boeing.com
Gayle Garman
Environmental Scientist
Coastal Protection & Restoration Division
National Oceanic & Atmospheric Administration
7600 Sand Point Way, NE
Seattle, WA 98115
206-526-4542
Fax: 206-526-6865
E-mail: gayle.garman@noaa.gov
Todd Gophs
National Oceanic & Atmospheric Administration
77 West Jackson Boulevard (SR-GJ)
Chicago, IL 60604
312-886-7527
E-mail: crc5@hazmat.noaa.gov
Nancy Grosso
Principal
DuPont Corporate Remediation
Barley Mill Plaza - Building 27 (2358)
Wilmington, DE 19880-0027
302-992-6783
Fax: 302-892-7637
E-mail: nancy.r.grosso@usa.dupont.com
Simeon Hahn
Coastal Resource Coordinator
National Oceanic & Atmospheric Administration
1650 Arch Street
Philadelphia, PA 19103
215-814-5419
Fax: 215-814-3015
E-mail: simeon-hahn-crc3@hazmat.noaa.gov
David Hohreiter
Senior Scientist
Blasland, Bouck & Lee, Inc.
6723 Towpath Road
P.O. Box 66
Syracuse, NY 13214
315-446-9120
Fax: 315-446-7485
E-mail: dh@bbl-inc.com
Robert Hoke
Senior Research Ecotoxicologist
Haskell Laboratory Division
DuPont Haskell Lab
1090 Elkton Road
P.O. Box 50
Newark, DE 19714
302-451-4566
Fax: 302-366-5003
E-mail: robert.a.hoke@usa.dupont.com
Joe Iovenitti
Vice President
Weiss Associates
5801 Christie Avenue - Suite 600
Emeryville, CA 94608
510-450-6141
Fax: 510-547-5043
E-mail: jli@weiss.com
Richard Jensen
Research Fellow
DuPont Corporate Remediation
Experimental Station 304
Wilmington, DE 19880
302-695-4685
Fax: 302-695-4414
E-mail: richard.h.jensen@usa.dupont.com
Michael Johns
Windward Environmental
200 West Mercer - Suite 401
Seattle, WA 98119
206-577-1280
Fax: 206-217-0089
E-mail: mikej@windwardenv.com
Robert Johnston
Scientist
Marine Environmental Support Office
U.S. Navy, Space and Naval Warfare Systems Command
4228 Fir Drive (D3621)
Brewerton, WA 98310
360-475-6988
Fax: 360-475-6901
E-mail: johnson@nosc.mil
Victoria Kirtay
Remediation Research Laboratory
Environmental Sciences
Space and Naval Warfare Systems Center San Diego
53475 Strothe Road - Room 267D Code 361
San Diego, CA 92152
619-553-1395
Fax: 619-553-8773
E-mail: kirtay@spawar.navy.mil
Ed Long
Marine Biologist
17631 83rd Avenue, SE
Snohomish, WA 98296
E-mail: elongwa@earthlink.net
Terry Lyons
Environmental Engineer
Office of Research & Development
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive (MS 489)
Cincinnati, OH 45247
513-569-7589
Fax: 513-569-7676
E-mail: terry.lyons@epa.gov
E. Erin Mack
Visiting Research Scientist
Dupont Central Research & Development
Glasgow Business Community 300
P.O. Box 6101
Newark, DE 19714-6101
302-366-6704
Fax: 302-366-6607
E-mail: elizabeth-e.mack@usa.dupont.com
Kelly Madalinski
Environmental Engineer
Technology Innovation Office
Office of Emergency & Remedial Response
U.S. Environmental Protection Agency
Ariel Rios Building (5102G)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
703-603-9901
Fax: 703-603-9135
E-mail: madalinski.kelly@epamail.epa.gov
Victor Magar
Senior Research Scientist
Battelle Memorial Institute
505 King Avenue - Room 10-1-27
Columbus, OH 43201-2693
614-424-4604
Fax: 614-424-3667
E-mail: magarv@battelle.org
Lawrence McCrone
Managing Scientist
Exponent
15375 Southeast 30th Place - Suite 250
Bellevue, WA 98007
425-519-8743
Fax: 425-643-9827
E-mail: mccronel@exponent.com
Patrick McLaren
President
GeoSea Consulting, Ltd.
789 Saunders Lane
Brentwood Bay, British Columbia V8M 1C5
Canada
250-652-1334
Fax: 250-652-1334
E-mail: patrick@geosea.ca
Karen Miller
Environmental Engineer
Restoration Development Branch
Environmental Restoration Division
Naval Facilities Engineering Services Center
1100 23rd Avenue (411)
Port Hueneme, CA 93043-4370
805-982-1010
Fax: 805-982-4304
E-mail: millerkd@nfesc.navy.mil
Paul Mudroch
Senior Environmental Officer
Environment Canada
49 Camelot Drive
Nepean, Ontario K1A 0H3
Canada
613-952-8677
Fax: 613-952-8995
E-mail: paul.mudroch@ec.gc.ca
Tommy Myers
Environmental Engineer
Environmental Restoration Branch
Waterways Experiment Station
U.S. Army Corps of Engineers
3909 Halls Ferry Road (CEERD-EP-E)
Vicksburg, MS 39180-6199
601-634-3939
Fax: 601-634-3833
E-mail: myerst@es1.wes.army.mil
Rob Pastorok
Exponent Environmental Group,
15375 Southeast 30th Place - Suite 250
Bellevue, WA 98007
425-643-9803
Fax: 425-643-9827
E-mail: pastorokr@exponent.com
Clay Patmont
Partner
Anchor Environmental, LLC
1411 Fourth Avenue - Suite 1210
Seattle, WA 98101
206-287-9130
Fax: 206-287-3131
E-mail: cpatmont@anchorenv.com
Greg Peterson
Vice President
Limno-Tech, Inc.
501 Avis Drive
Ann Arbor, MI 48108
734-332-1200
Fax: 734-332-1212
E-mail: gpeterson@limno.com
David Rabbe
President
Chemical Land Holdings
Two Tower Center Boulevard - 10th Floor
East Brunswick, NJ 08816
732-246-5848
Fax: 732-246-5858
E-mail: davermxs@aol.com
Danny Reible
Director and Professor of Chemical Engineering
Hazardous Substance Research Center
Louisiana State University
3221 CEBA
Baton Rouge, LA 70803
225-388-3070
Fax: 504-388-5043
E-mail: reible@che.lsu.edu
Cornell Rosiu
Environmental Scientist
U.S. Environmental Protection Agency
1 Congress Street - Suite 1100 (HB5)
Boston, MA 02114-2023
617-918-1345
Fax: 617-918-1291
E-mail: rosiu.cornell@epa.gov
Richard Sheets
President
Sheet & Sons Environmental Associates
7865 Northeast Bay Road, W
Bainbridge Island, WA 98110
800-546-5022
Fax: 206-842-9014
E-mail: soils@soils-sti.com
Merton (Mel) Skaggs
Principal
In Depth Environmental Associates
P.O. Box 92653
Southlake, TX 76092
817-741-4332
Fax: 817-741-4333
E-mail: mmsnsl@aol.com
Ralph Stahl
Senior Consulting Associate
DuPont Corporate Remediation
Barley Mill Plaza #27
Route 141 and Lancaster Pike
Wilmington, DE 19805
302-892-1369
Fax: 302-892-7641
E-mail: ralph.g.stahl-jr@usa.dupont.com
Robert Stamnes
Engineer
U.S. Environmental Protection Agency
1200 6th Avenue (OEA-095)
Seattle, WA 98101
206-553-1512
Fax: 206-553-0119
E-mail: stamnes.robert@epa.gov
Jeff Stern
Sediment Management Program Manager
King County Department of Natural Resources
201 South Jackson Street (KSC-NR-0503)
Seattle, WA 98104-3855
206-263-6447
Fax: 206-684-1741
E-mail: jeff.stern@metrokc.gov
Mike Swindoll
Environmental Scientist
Toxicology & Environmental Sciences Division
ExxonMobil Biomedical Sciences, Inc.
1545 Route 22 East
P.O. Box 971
Annandale, NJ 08801-0971
908-730-1006
Fax: 908-730-1199
E-mail: mswindo@erenj.com
Mark Terril
Manager, Site Remediation
PPG Industries, Inc.
4325 Rosana Drive - Building C
P.O. Box 2009
Allison Park, PA 15101
412-492-5532
Fax: 412-492-5377
E-mail: terril@ppg.com
Neil Thompson
Environmental Engineer
U.S. Environmental Protection Agency
1200 Sixth Avenue (ECL-113)
Seattle, WA 98101
206-553-7177
Fax: 206-553-0124
E-mail: thompson.neil@epa.gov
Ernest Watkins
Environmental Protection Specialist
Region 5/7 Accelerated Response Center
Office of Emergency and Remedial Response
U.S. Environmental Protection Agency
401 M Street, SW (5202G)
Washington, DC 20460
703-603-9011
Fax: 703-603-9132
E-mail: watkins.ernie@epa.gov
J. Kenneth Wittle
Vice President
Electro-Petroleum, Inc.
996 Old Eagle School Road - Suite 1118
Wayne, PA 19087
610-687-9070
Fax: 610-964-8570
E-mail: kwittle@aol.com
Jack Word
Principal
MEC Analytical Systems
152 Sunset View Lane
Sequim, WA 98382
360-582-1758
Fax: 360-582-1679
E-mail: word@mecanalytical.com
RTDF/Logistical and Technical Support Provided by:
Christine Hartnett
Conference Manager
Eastern Research Group, Inc.
5608 Parkcrest Drive - Suite 100
Austin, TX 78731-4947
512-407-1829
Fax: 512-419-0089
E-mail: chartnet@erg.com
Carolyn Perroni
Senior Project Manager
Environmental Management Support, Inc.
8601 Georgia Avenue - Suite 500
Silver Spring, MD 20910
301-589-5318
Fax: 301-589-8487
E-mail: carolyn.perroni@emsus.com
Laurie Stamatatos
Conference Assistant
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3136
781-674-7320
Fax: 781-674-2906
E-mail: lstamata@erg.com
Chipper Whalan
Conference Coordinator
Eastern Research Group, Inc.
2200 Wilson Boulevard - Suite 400
Arlington, VA 22201
703-841-0500
Fax: 703-841-1440
E-mail: ewhalan@erg.com
Attachments B through F
Attachment
B: Overview
of Monitored Natural Recovery (John Davis)
Attachment
C: Using Natural Processes to Define Exposure from Sediments (Danny Reible)
Attachment
D: New Approaches to Studying Sediment Transport (Patrick McLaren)
Attachment
E: Role of Modeling in Assessing Natural Recovery (Mike Erickson and Greg Peterson)
Attachment
F: The Role of Ecological Modeling in Assessing Natural Recovery of Sediments
(Rob Pastorok)