SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
SEDIMENTS REMEDIATION ACTION TEAM MEETING

Crowne Plaza Cincinnati
Cincinnati, Ohio
May 8, 2000

WELCOME AND OPENING REMARKS
Richard Jensen, DuPont Corporate Remediation

Richard Jensen, co-chair of the Remediation Technologies Development Forum (RTDF) Sediments Remediation Action Team, opened the meeting by welcoming participants. (Attachment A lists the meeting attendees.) Jensen gave an overview of the agenda items for this meeting. He also added something to the scheduled agenda items: a videotape he had brought that described a field demonstration of the AquaBlok™ technology.


WORK BEING PERFORMED BY EPA'S CINCINNATI LABORATORY

Natural Attenuation Field Study Project
Richard Brenner, National Risk Management Research Laboratory (NRMRL), U.S. Environmental Protection Agency (EPA)

Richard Brenner described a cooperative program between EPA and Battelle that was created to study the recovery of contaminated sediments through natural attenuation. The Battelle work assignment leader, Dr. Victor Magar, attended the meeting and made himself available to answer questions.

Overview of Natural Attenuation Processes

Before Brenner discussed the cooperative program, he provided background information about natural attenuation processes. Four mechanisms contribute to natural attenuation: (1) natural capping through sedimentation, (2) anaerobic dechlorination, (3) aerobic and anaerobic biodegradation, and (4) sorption to particles to reduce bioavailability. Dechlorination of polychlorinated biphenyls (PCBs) reduces the number of chlorines, which in turn reduces toxicity. Polyaromatic hydrocarbon (PAH) biodegradation preferentially reduces the lower-weight PAHs, reducing overall PAH mass in the process. Scientists once thought that biodegradation was the largest contributor to natural attenuation. However, biodegradation is a very slow process, and is only a minor contributor to reduction in contaminant mass and concentration. Scientists now believe that natural attenuation is most applicable at sites where sedimentation has created natural caps. A natural cap keeps contaminants from migrating to the water column as long as it is not disturbed; the cap reduces contact between the contaminated sediment and water, diffusion and advection in the vertical direction, and bioturbation.

Program Objectives and Background Information on Field Sites

Brenner discussed the cooperative program's objectives. The program's first objective, he said, is to develop a sampling and analysis protocol that (1) determines contaminant concentration as a function of depth, and (2) statistically correlates depth with age. No protocol of this type existed prior to this effort. The second program objective is to test this protocol in the field. Studies have been initiated at two sites:

• The Lake Hartwell site. Brenner said that this is a Superfund site located in South Carolina. A capacitor manufacturing plant, which operated for 23 years from the 1950s to the 1970s, was located along a creek that contributes to Lake Hartwell. This plant released an estimated 400,000 tons of PCB-contaminated material to the sediments in the creek and Lake Hartwell. Natural attenuation was selected to remediate sediment contamination. The plant also released contaminants to the soil, but soil remediation has been completed. There are several dams in the creek upstream of the lake. These dams collect sand, which the operators periodically flush into the creek. This sand settles on the creek bed before it reaches the lake.

• The Eagle Harbor site. This site is a marine sediment site in Puget Sound near Seattle, Washington. The site was placed on the National Priorities List in 1987; it is contaminated with PAHs that were released by a creosote plant. The plant ceased operations in the mid-1980s, after approximately 85 years of active use. The terrestrial source of the PAHs has not been remediated, but remediation is planned for summer 2000. Some sediment capping has been completed in portions of the site.

Description of the Protocol and Field Activities

As noted above, EPA and Battelle developed a sampling and analysis protocol. It explains how to (1) determine contaminant concentration as a function of depth, and (2) statistically correlate depth with age. They designed the protocol to examine contaminant reduction over time by examining how contaminant concentrations differ at different depths. Because of the preferential reduction of lower-weight PAHs, EPA and Battelle hypothesized that a reduction in the relative proportion of lower-weight PAHs with depth would indicate that natural attenuation was occurring. Magar said that they measured relative proportion because more PAHs were deposited in the 1970s and early 1980s, meaning that the total PAH concentration was higher at lower depths. Deposition declined in the 1990s as remediation occurred and, as a result, the total PAH concentration was lower near the surface. At the Eagle Harbor site, reduction in relative proportion of PCBs with more chlorines would indicate that dechlorination was occurring. Brenner said that sample collection was complete at the test sites and samples were being analyzed. Preliminary data support their hypothesis.

At each site, sediment and surface water samples were collected at 10 locations. At each sampling location, investigators collected three co-located sediment cores, each of which was 40 to 80 centimeters (cm) long. Each core was extruded to 5 and 10 cm long segments for analysis. Segment lengths were based on the sediment mass needed for each analyses. Investigators did not homogenize the sediments from each core before analysis. Each segment represented deposition over a 2- to 4-year period, so each core represented deposition over a 20- to 50-year period. Deposition rates ranged from 0.5 to 2 cm per year. One 5 cm long segment was analyzed for the target contaminant (either PCBs or PAHs), a second 5 cm long core was analyzed for lead²¹⁰ (Pb-210) and cesium¹³⁷ (Cs-137), and one 10 cm long core was used in partitioning studies to assess bioavailability.

An audience member asked if smearing in the cores could confound results. Magar replied that there was no visual evidence of smearing. Compaction was a greater concern. They were able to determine that compaction occurred, but they could not determine if the compaction occurred uniformly in the core or if it was concentrated in one segment of the core.

EPA and Battelle used Pb-210 and Cs-137 analyses to age-date the sediment because these isotopes (1) are ubiquitous in the environment, (2) have a relatively constant flux rate, (3) are naturally occurring or are the result of atmospheric fallout from nuclear testing, and (4) have long half lives (20 to 30 years). Brenner said the laboratory is now sending results from the Pb-210 and Cs-137 tests.

Because rates of contaminant diffusion to the water column may be controlled by desorption, partitioning studies are now being conducted. These studies involve adding contaminated sediment to clean water; six different levels of contaminant concentration are being studied.

An audience member asked about the cost of each analysis. Magar answered that the PCB analysis cost $250 per sample and the age-dating was $200 per sample. The cost of the partitioning studies could not be estimated.

At the Lake Hartwell site, samples were collected along transects established for an earlier investigation. Investigators used a depth meter to find the point along each transect with the greatest water depth and slowest flow rate; they assumed that sediment deposition would be greatest at this point. At the Eagle Harbor site, EPA and Battelle collected sediment cores west and south of the existing caps. Sampling was completed in late March 2000, and analyses are being conducted now.

Preliminary Program Results

At the Lake Hartwell site, PCBs have been detected at levels up to 100,000 parts per billion (ppb). Most of the PCBs are in the silts. For each core, Brenner said, investigators expected to see PCB concentration versus depth as a bell-shaped curve. The samples collected in the upper portions of the study area contain sand and silt layers (from sand flushed from upstream dams). Samples collected near Lake Hartwell contain only silt. The sand affected analyses and study results. The curves for the samples with sand were interrupted, because PCBs were not found, or were found at low concentrations, in the sand. A bell-shaped curve was seen in the cores composed only of silt. At the surface, PCB concentrations were low, indicating natural capping with clean sediments. Below the surface, PCB concentrations were at their highest during the peak manufacturing years, declining at lower depths. Age-dating results are not complete, but preliminary data show that PCB concentrations peaked between 1980 and 1982. Magar said the manufacturing plant closed in 1978, meaning that some lag effect had occurred; they are still investigating this. An audience member asked if Brenner and Magar had conducted congener profiles. Magar said that they are conducting profiles for 107 congeners. Preliminary results have shown patterns for several congeners and indicate that some dechlorination is occurring.

At the Eagle Harbor site, preliminary results show that PAH profiles are consistent with creosote contamination and that there is a relative reduction in the lower-weight PAHs with depth. Magar said that age-dating analysis is ongoing, so depth cannot be correlated with age yet. Preliminary results show that natural attenuation is occurring, but no attempt has been made to determine what processes (biological, physical, or chemical) are contributing to this natural attenuation. An audience member asked if seeps could transport contamination in the subsurface sediments to the surface. Magar answered that samples collected west of the cap were not impacted by seeps. PAH contamination was from continuous deposition of contaminated sediments. Samples collected south of the cap, however, were likely impacted by seeps. This will affect how results are interpreted.

Closing Remarks

Brenner said that additional chemical analyses, partitioning studies, and data evaluation are ongoing at the program's two field sites. Studies at these sites are scheduled to end on September 30, 2000. A report summarizing results will be prepared before that time. Brenner said that EPA and Battelle hope to write several papers summarizing their findings. In addition, they hope to continue this program at up to five more sites, one of which is located in the New York Harbor. The decision to move forth with additional field activities will be dictated by funding availability.

The Superfund Innovative Technology Evaluation (SITE) Program
Annette Gatchett, NRMRL, EPA

Annette Gatchett manages and operates EPA's SITE program. She described the program and explained how it operates. (Gatchett's presentation materials are included as Attachment B.) The SITE program was formed 13 years ago. Although its operation has changed significantly in the past 3 or 4 years, the program's main goal--to test and verify innovative treatment technologies for hazardous waste--has remained the same. Instead of EPA seeking technologies, however, the program has moved toward a market-driven approach in which site owners contact EPA for assistance. The SITE program also evolved to emphasize lower-cost technologies and priority environmental areas. The program aims to build stronger partnerships with other federal, state, and private organizations; to continue evaluating low-cost technologies; and to address more difficult contamination problems.

To date, the SITE program has completed 110 field demonstrations and 39 monitoring demonstrations. According to analysis of data from Records of Decision (ROD) documents, an average of 66% savings per site has been achieved. A survey of participating vendors reported a 20% to 75% increase in revenue, with 44 vendors holding approximately 3,000 remediation contracts. EPA also estimated that the SITE program has saved $2.1 billion since its inception. Gatchett said this number was calculated by evaluating RODs that selected innovative technologies, comparing the cost of the innovative technology to the cost of the standard technology, extrapolating savings, and subtracting the SITE program operation costs. Gatchett presented a graph displaying cost savings by technology type. Of the technologies, she said, phytoremediation, bioremediation, passive barriers, and in-situ oxidative and thermal techniques hold the greatest promise for cost savings.

The SITE program always uses one of two methods to select technologies for evaluation: annual solicitation or fast-track requests. The annual solicitation begins each fall. A selection team reviews applications and picks six to eight technologies for demonstration. Gatchett said that the selection team is now picking technologies for 2000. Fast-track requests come from EPA regions that contact the SITE program about sites that must be remediated quickly. If a site is in one of the priority areas, the SITE program conducts an independent review and selects the site for a technology demonstration. When applying to the SITE program, vendors and site owners may propose a site and an innovative technology together. Site owners may also present just the site, in which case EPA works with them to identify innovative technologies. More than one technology can be demonstrated at a site. Once the sites and technologies are selected, the SITE program designs test plans, conducts field work, analyzes data, and writes reports. If the demonstration is successful, the innovative technology may be selected for remediation.

The selection team is composed of members from the Interstate Technology and Regulatory Cooperation (ITRC) Work Group, the Department of Defense's (DOD's) Environmental Security Technology Certification Program (ESTCP), the Department of Energy (DOE), the EPA Office of Research and Development (ORD), EPA regional staff, and EPA Program Offices. ITRC is a work group composed of representatives from approximately 27 states. DOD's ESTCP is similar to the SITE program; Gatchett is a member of the ESTCP selection team. Gatchett said that she considers the EPA regional staff and EPA Program Offices to be the SITE program's primary clients. In addition to selecting technologies for demonstration, this team annually reviews and develops the list of priority areas.

The cost of a field demonstration is shared between the SITE program, the site owner, and the technology vendor. The SITE program funds the test plan, the sampling and analytical program, and report writing, which costs an average of $500,000 per field demonstration. The site owner is responsible for all infrastructure (roads, utilities, etc.), for residual waste disposal, and for holding a visitor's day to educate the public about the site and its remediation. The vendor is responsible for all their equipment and its operation and maintenance. The SITE program does not fund equipment in order to maintain third party credibility, which is the foundation of the program.

In the past, the SITE program selected emphasis areas based on types of contaminants. The selection committee revised the emphasis areas for the fall 2001 application to focus on categories of sites, such as manufactured gas plants, wood treatment sites, or brownfields. Past applications addressing types of contaminants usually proposed demonstration projects at these types of sites. Over time, the SITE program has selected an increasing number of in situ technologies for demonstration, because in situ technologies can be less expensive and may be needed to address more complex site contamination problems.

Gatchett discussed dense non-aqueous phase liquids (DNAPL) and sediment remediation as areas of future research. At Cape Canaveral, the SITE program, in cooperation with the National Aeronautics and Space Administration (NASA), DOD, DOE, and ITRC, was conducting a demonstration of one oxidative and two thermal technologies for treating DNAPL. In 1996, the SITE program received some applications involving sediment treatment technologies. They rejected these applications, because the sites only had limited site characterization data.

Since its inception, the SITE program has demonstrated three treatment and two monitoring technologies for sediments. The technology demonstrations, completed in 1988, 1991, and 1992, evaluated sediment washing or solvent extraction techniques. The two monitoring demonstrations, completed in 1999, evaluated a split-core sampler and the Russian peat borer. Two sediment treatment technology demonstration projects are scheduled to commence in late summer 2000: the minergy glass furnace technology and the cement-lock technology. The glass furnace technology uses vitrification to create a glass-like tile that can be sold for reuse. The Cement-Lock Technology is a thermo-chemical process that produces construction-grade cement that can be utilized for manufacturing concrete. Audience members discussed the potential for contaminants to leach from the end products. Gatchett said that the SITE program would evaluate leachability. An audience member said the thermal treatment would destroy the organic contaminants, so leaching would only be a concern for the inorganic contaminants. Gatchett said that the SITE program also plans to evaluate (1) the AquaBlok™ technology, and (2) a confined-disposal facility technology. AquaBlok™ is a capping technology; it may be demonstrated on mercury-contaminated sediments at a site in Alabama. The confined-disposal facilities technology has been tentatively picked for demonstration during the current selection process. This technology uses phytoremediation and biostabilization to address PCB, PAH, and metal contamination.

Gatchett said that the SITE program has produced a three-volume document of technology profiles that summarize demonstration results. People can order documents or get more information by contacting the Center for Environmental Research Information (1-800-490-9198 or 513-569-7566) or the National Technical Information Service (1-800-553-6487 or 703-605-6000).More information about the program can be found on the Internet at http://www.epa.gov/ORD/SITE or http://www.epa.gov/ETV; information about the program's laboratories can be found at http://www.epa.gov/ORD/NRMRL/lrpcd and http://www.epa.gov/ada/.

Jensen asked if the SITE program required regional approval for a demonstration project. Gatchett answered that the program always obtained regional agreement and that, in many cases, the regions submitted applications in conjunction with site owners.

Gatchett mentioned that the SITE program has been discussing potential demonstration projects at Pearl Harbor. Pearl Harbor has many types of sites and contamination and it has been very well characterized. The SITE program has not yet been able to demonstrate any remediation technologies there, because the Navy is still developing the remediation goals and sediment contamination sources are still present and active.

An audience member asked if the SITE program had a goal for the number of new sites or technologies selected each year. Gatchett answered that six sites were tentatively selected in 2000 and that the fast-track process usually adds four more.

POTENTIAL FIELD DEMONSTRATION PROJECTS

Paleta Potential Capping Site
Sabine Apitz, Space and Naval Warfare Systems Center

Sabine Apitz said that she is working with a group of Action Team members to identify a demonstration that can be used to evaluate sediment capping technologies. (Apitz's presentation materials are included as Attachment C.) She provided an update of activities that have occurred since the last Action Team meeting in San Diego in January 2000. At the last meeting, she discussed the Seaplane Lagoon site in California as a possible demonstration site. This site was selected because it was well characterized and comprehensive site data were available. If this site had been chosen, the demonstration would have established a grid system over the contaminated areas. To test different capping technologies, investigators would have installed them at different points in the grid. The Navy project officer, however, said that this demonstration project could not be conducted because of the remediation and site transfer schedule. As a result, Apitz said, the Action Team members submitted a proposal to ESTCP for a sediment capping demonstration project, with Paleta Creek presented as a potential study.

Paleta Creek is located within a Navy station near San Diego. The Navy and regional agencies are interested in remediating this site because it is designated as a toxic hot spot under the Bay Protection and Toxic Hot Spots program. The site is designated this way because of PAH, chlordane, and total chemistry concerns. Overall, site contaminants include PAHs, pesticides, and metals at moderate levels, below concentrations found at sites on the East Coast. The site is subject to shipyard activities, but the contaminant signature indicates that the primary source is urban runoff. Because it is a shipyard, there is dredging in the channels and near piers, but dredging does not occur in the shallow areas where contaminant hot spots are located.

Paleta Creek has been the target of extensive past, current, and future investigations. Apitz provided a brief summary of these studies. The laboratory where she worked used samples from Paleta Creek to study anaerobic biodegradation. A member of her laboratory conducted a study of benthic flux, bioaccumulation, sediment characterization, hydrodynamics, and sediment treatability at Paleta Creek. Most of the data from this study are unpublished. Apitz said that the Navy and regulatory agencies were discussing a multi-investigator study to examine natural attenuation processes at Paleta Creek. Because the site is a designated toxic hot spot, the Navy, the Port District, and the City of San Diego are conducting an investigation that first examined historical site data and then sampled to fill data gaps. The historical data review examined upland sources, because there was concern that upland sources were still contributing to site contamination. Jensen asked if the site was big enough for both the proposed natural attenuation studies and a capping demonstration. Apitz replied that this question has not been answered.

Apitz presented data for metal contamination at the site. Elevated zinc, copper, lead, and chromium have been detected; some of these increase in concentration with depth. Jensen noted that the data did not indicate that sedimentation was occurring. Apitz agreed. Because the site is an active shipyard, there is resuspension, deposition, and mixing of the sediments. PAH contamination distribution is very heterogeneous, indicating mixing and disturbance. Recorded PAH concentrations are moderate, with the highest reported concentration at 80 parts per million (ppm). Preferential accumulation of the higher-weight PAHs indicates weathering and some natural attenuation. PAH input to the San Diego Bay, however, has decreased over time, so data must be analyzed to distinguish between decreases caused by reduced input and decreases caused by natural attenuation. (In many cases, the input contamination has already been weathered; therefore, this analysis will be difficult.) In addition to the metals and PAHs, some PCB contamination is present, with concentrations of approximately 300 ppb. There is a distinctive Aroclor-209 signature. Aroclor-209, a component of a waxy casting material used until the 1970s, was introduced by industrial sources.

An audience member asked if there are plans to address ongoing sources, such as runoff, before installing caps. Apitz answered that historical data will be studied to confirm that the area should receive significant attention and to identify sources before remediating. Initial data indicate that runoff is the contamination source, but there is also political pressure to study the site.

Apitz said that she is waiting to hear if funding for the proposed project has been approved. She is not committed to using Paleta Creek as a demonstration site, and Seaplane Lagoon has not been wholly discounted. If funded, she will seek another possible demonstration site with higher contamination levels than at Paleta Creek.

One audience member suggested that Pearl Harbor might be a good demonstration site. Apitz said she had been involved in demonstrating some sampling and characterization technologies at Pearl Harbor. She agreed that this would be a good demonstration site: it is well characterized and there are many different types of sites and contaminants that need to be addressed. A copy of the ESTCP proposal has been sent to the Pearl Harbor project officers, and Apitz is pursuing connections at that site. Apitz has reviewed site data and has found that Pearl Harbor's mix of sources and contamination is complex; therefore, she believes that containment and in situ management are the best treatment options.

Gatchett said the SITE program is also pursuing Pearl Harbor as a demonstration site. The ongoing source makes it difficult to conduct demonstrations at Pearl Harbor. A possible solution would be installing barriers to keep contaminants from entering the source area during remediation. Remediation goals have not been established, which presents another problem. Gatchett mentioned that there is one area of DDT contamination at Pearl Harbor that has no ongoing source and could serve as the first site for demonstration projects.

One audience member asked how the RTDF could help or coordinate efforts to conduct field demonstrations of sediment remediation technologies. Gatchett responded that members of the ESTCP and SITE programs participated in the selection teams for both programs and were able to coordinate DOD and EPA efforts. RTDF members could provide technical review of test plans, present sites for technology demonstrations, or establish partnerships with agencies. Jensen said that a capping demonstration site must meet certain criteria: there must be no ongoing sources, some natural attenuation should be occurring, and the region must agree with the proposed project.

SEDIMENT REMEDIATION TECHNOLOGIES

Manufactured Soil and Phytoremediation Technologies
Charles Lee, U.S. Army Corps of Engineers (USACE), Engineer Research and Development Center (formerly the Waterways Experiment Station)

Each year, USACE dredges approximately 300 million cubic yards of materials. One of USACE's biggest concerns is determining where to use or dispose of this dredge material--both clean and contaminated. USACE has sponsored and funded a number of programs to address this concern, including the Dredge Material Research Program, Long-Term Effects of Dredging program, Dredging Operations Technical Support program, Dredging Operations Environmental Research (DOER) program, and Dredging Research Program. Charles Lee described a research project that he has been involved with. Under one of USACE's research programs, he is testing manufactured soil and phytoremediation technologies to determine whether they can convert dredge material into reusable soil.

Dredge Material Reuse Research

In his attempt to find ways to convert dredge material into reusable soil, Lee established a Cooperative Research and Development Agreement (CRADA) with a private company. This company has created a manufactured topsoil by blending clean dredge material with cellulose (yard waste, saw dust, or paper) and biosolids (reconditioned sewage or animal wastes). Lee said that these materials must be blended in certain proportions to ensure that a viable topsoil is created; thus the private company has developed blending techniques and assessment methods. These have been shared with Lee.

In an effort to create a reusable soil from contaminated dredge material, Lee and his co-worker Richard Price are conducting manufactured soil and phytoremediation studies with contaminated dredge materials. They use the soil blending techniques provided by the private company to blend contaminated dredge material with cellulose and biosolids. Assessment methods are used to determine if the blended material is a viable manufactured soil for plant growth. Once a viable soil is created, phytoremediation is applied to remediate the contamination. (Lee said that phytoremediation can be used to contain, concentrate, or degrade contaminants. Containment applications use plants to prevent erosion and contaminant migration. Applications that concentrate contaminants use hyperaccumulator plants to uptake contaminants, mainly metals; the plants can be harvested and the metals reclaimed, removing them from the site. Other plants can be used to degrade organic contaminants from a site; USACE has studied degradation of PAHs, PCBs, dioxins, TNT, and RDX.) Apitz asked how deep the phytoremediation occurred. Lee answered that the phytoremediation occurred to the root depth. He thought USACE could remediate the surface layer, remove that layer for reuse, and then remediate the underlying soil. Another audience member asked how phytoremediation plants are selected. Lee answered that plants are selected based on contamination type, site characteristics, and personal preference. Native plants are preferred. Lee favors creating the manufactured soil, conducting phytoremediation using the most efficient plant, and then introducing native species as phytoremediation is completed.

Lee said that the manufactured soil technology can be used to apply phytoremediation at sites whose conditions make it difficult to grow plants. Lee said that USACE could apply this process to military training areas, demolition areas, or ordnance impact areas. He noted that, if contaminated materials are being used, the manufactured soil should have limited reuse until phytoremediation remediates the material.

Ongoing Manufactured Soil Projects

Lee described the Hamlet City Lake site in North Carolina; USACE's first manufactured soil and phytoremediation project has been established at this site. He said that dredge materials from the lake were contaminated with PAHs and total petroleum hydrocarbons (TPH) that came from a former railroad. Past locomotive cleaning practices released oil and grease to the lake. USACE dredged the lake and placed the contaminated material in a confined disposal facility. Lee conducted plant bioassays using manufactured soil to examine phytoremediation options. He blended the contaminated dredge material with manure to create a soil that supported plant growth. After six months of plant growth, TPH in the manufactured soil that contained 50% dredge material and 50% manure was reduced by 70% to 75%. Analysis of the effluent from the confined disposal area, however, detected copper. To treat the copper, USACE manufactured a wetland soil. Wetland plants were carefully selected to create a reducing environment that would cause the copper to sorb to the wetland soil. (An oxidizing environment would allow the copper to remain in solution.) Lee said that USACE was also investigating constructed wetlands as a way to remove organic contaminants, metals, nitrogen, and phosphorous from waters. Constructed wetlands could be used to treat agricultural runoff, landfill leachate, acid mine drainage, and industrial waste water.

Lee also discussed a study that is being performed on sediments from New York Harbor. These sediments, he said, contain multiple contaminants, as well as salt from the saline environment. Lee's project involved blending dredge materials from the harbor to create a manufactured soil for phytoremediation. The dredge materials were blended with yard wastes and animal biosolids at different ratios, and screening studies were conducted to identify a viable mixture. For the screening tests, the materials were blended and a rye grass was planted immediately. There was no interim treatment. The screening tests indicated that salt was the limiting factor for soil viability. Once a viable blend was found, the manufactured soil was spread over field test beds and three phytoremediation techniques (containment, concentration, and degradation) were tested. The field test beds, which were 6 foot square plots, were equipped with drainage and leachate systems. They were monitored over a 15-month period. Lee presented data for fluoranthene to show how the dredged material was impacted by treatment. Fluoranthene was present at approximately 30 ppm in the dredge material. After blending, that concentration dropped to 12 ppm, and after 15 months of phytoremediation the concentration was less than 1 ppm. However, similar degradation of PCBs and dioxins was not seen. An audience member mentioned that Alcoa, Inc., completed a phytoremediation demonstration for PCBs in sludges. The project lasted six or seven years and found PCB reduction in the soil and leachate. Data from this study were not published. Jensen asked if Lee had calculated how much time or space would be needed to apply this technology on a larger scale. Lee said he had not done this calculation, since the intent of the study was to determine if the technology was feasible. Preliminary data indicated that the technology was feasible and that possible application included landfill covers, acid mine lands, or brownfield sites.

Lee said that he is also involved in a project that involves treating dredge material generated by the New York City Parks Department. This is the largest manufactured soil and phytoremediation project to date. The Parks Department would like to reclaim 50,000 cubic yards of sediments that they dredged from freshwater streams and ponds for reuse as topsoil. The sediment, however, contains PAH contamination (up to 1 ppm) and low levels of lead. Lee said that the treatment effort would involve blending the dredge material with yard waste from park operations and animal manure from mounted police. The blended material would be applied to an unused park area for a one-year phytoremediation program. The blending would reduce lead to the remediation goal of 38 ppm and phosphorus would be added to bind the lead.

At Pearl Harbor, Lee was asked to apply the same manufactured soil and phytoremediation process that was applied to the New York Harbor sediments. Pearl Harbor sediments, like those from New York Harbor, are in a saline environment. Lee said that the sediments are a fine silt and are contaminated with PAHs. These sediments have been blended with a cellulose (yard waste, wood, and shredded paper) and a biosolid (swine manure). Screening tests were conducted.

Proposed Manufactured Soil Projects

Lee said that a site in Milwaukee, Wisconsin, has dredge materials--contaminated with PAHs and lead--that have already been blended with wood chips to create biopiles. Lee said that he proposes applying the manufactured soil and phytoremediation technology at this site. The lead remediation goal is 30 ppm. Lee's proposed study would investigate an extraction process and mustard plants to remove the lead. It would also assess phosphate immobilization and other treatment options to address the lead. (The immobilization technology will be tested because USACE is considering making immobilization the preferred treatment option for lead.) In addition, he said, earthworm bioassays would be conducted to assess toxicity. Jensen asked if the phytoremediation technology and the immobilization technology would be used sequentially to treat the lead. Lee replied that these technologies will be applied to two separate test plots. He plans to study what measures would be needed to assess the phytoremediation technology. (Leachate collection is one possibility.)

There is also a proposal in process under USACE's CRADA to remove 800,000 cubic yards of dredge material from a confined disposal facility each year for the next 10 years until the facility is empty. This proposal would create a commercially reusable soil. There is another proposal in process to place manufactured soil at a 3-acre landfill demonstration site. Lee said that the manufactured soil and phytoremediation process has been successful for PAHs, but application to other contaminants still needs study.

Comments

Dennis Timberlake asked if Lee knew what happens to contaminants once they enter plants. He asked whether they are destroyed, volatilized, or accumulated in the plant material. An audience member said that PAH phytoremediation studies found that soil microbes, not the plants, were biodegrading the contaminants. The plants provided a habitable environment for the microorganisms. Danny Reible said that TNT phytoremediation studies found that TNT was degraded in the plants, but very little detoxification occurred. Phytoremediation processes were not as well understood for other contaminants.

Some plant enzymes remain active even after plants are destroyed. Jensen asked if Lee had considered conducting studies using plant mixtures applied to soils. Lee said he had reviewed proposals to grind plants into the soil, as well as proposals to turn them into a slurry before applying them to soil. Lee believed these were interesting ideas, but felt growing the plants on the soil would be easier.

AquaBlok™ Demonstration Capping Project Videotape
Produced by 2000 AquaBlok, Ltd.

Jensen played the AquaBlok™ Demonstration Capping Project videotape. John Hull introduced the videotape and answered questions. AquaBlok™ is a manufactured capping material composed of rock and bentonite. When hydrated, the bentonite expands to create a sealed sediment cap. The AquaBlok™ material has low permeability and is resistant to erosion. Hull said that AquaBlok™ could be used as a remediation tool by itself or in conjunction with other technologies.

The video program described an AquaBlok™ demonstration project that was conducted in September 1999 in the Ottawa River. The Ottawa River is a highly industrialized river that flows into Lake Erie. Historical practices contaminated the river sediments with PCBs. The demonstration project was conducted to assess three AquaBlok™ application methods: shore-based and barge conveyer systems, shore-based draglines, and a helicopter. Approximately 500 tons of AquaBlok™ were placed over a 2.5- to 3-acre area of sediment contamination. The 1.5 to 2.5 inches of AquaBlok™ distributed over the demonstration area expanded to a depth of 4 to 6 inches after hydration. The field demonstration found that each of these methods successfully provided uniform cap material application. More information about AquaBlok™ is available at http://www.aquablokinfo.com.

Apitz asked how investigators determined that the AquaBlok™ had been placed on top of the sediment and had not mixed with it. Hull said they collected core samples and could see a distinct boundary between the AquaBlok™ and the sediment.

Finkelstein asked if any pre- and post-application benthic community studies were conducted. Hull said that the Department of Fish and Wildlife requested benthic community studies, and that the Ohio Environmental Protection Agency (OEPA) completed a benthic community study before the AquaBlok™ application. The report has not been finalized, but will be available at the Lake Erie Commission Web site. Overall, OEPA found that the site was sterile. There are plans to conduct a followup study in 2001. Hull said they cannot predict if an improvement will be seen, because a nearby Superfund site may still be contributing contamination to the Ottawa River. Hull said that the goal of the demonstration was to assess application methods, not necessarily provide permanent remediation.

Finkelstein asked how deep the water at a site must be for the barge application method to be used. Hull said that the water must be at least 5 feet deep.

In response to a question about site monitoring, Hull said that monthly visual inspections are conducted at the site. These inspections indicate that the AquaBlok™ was still in place after the winter and spring runoff. A cross-section study is planned for fall 2000.

An audience member asked what produced the dust seen in the videotape during application. Hull said the dust was from the soft limestone rock used in the AquaBlok™.

Another audience member asked how the AquaBlok™ material applied above the water line was hydrated. Hull said capillary action hydrated those areas, but that the AquaBlok™ would not fully expand until it was submerged. Studies also found that if the AquaBlok™ was applied too quickly, it would not fully hydrate because it would seal itself.

One audience member asked if AquaBlok™ is resistant to bioturbation. Hull said that no bioturbation studies have been completed. People using AquaBlok™ should apply a thick enough layer to address the bioturbation zone. AquaBlok™ is a pliable material and will seal itself after being disturbed. At a site in Alaska where AquaBlok™ was applied, revegetation occurred and the AquaBlok™ resealed around the plant stems. Another audience member suggested that armoring could be used in conjunction with the AquaBlok™ to prevent bioturbation.

An audience member asked what stream velocities an AquaBlok™ cap can withstand. The Ottawa River has a 100-year flow velocity of 4.8 feet per second for approximately 1 hour. Flume tests of similar AquaBlok™ compositions withstood water velocities of 6 feet per second for 50 hours with an approximately 10% product loss. In comparison, a sand or silt cap would erode at flow velocities of 1 to 2 feet per second. Armoring could be applied to reduce erosion.

When asked if any bioassays had been conducted to determine if organisms would inhabit the AquaBlok™ material, Hull said no bioassays had been completed but that they are planned. AquaBlok™ has been applied at a site in Alaska, he said, where concerns have been expressed about duck, eagle, and whale mortality. No baseline studies were conducted at this site, but cores were collected one year after the AquaBlok™ application; some red worms were detected.

NATURAL RECOVERY SUBGROUP
John Davis, The Dow Chemical Company

John Davis spoke to the Action Team to garner interest in developing a Natural Recovery Subgroup, which would be similar to the Assessment Subgroup. (Davis's presentation materials are included as Attachment D.) The new Subgroup's objective would be to write white papers summarizing the Action Team's experience with the technical issues related to natural recovery. Davis proposed beginning this task by gathering interested parties in conference calls. These calls would begin with a technical review of several papers issued by the Sediment Management Work Group (SMWG). SMWG is an ad hoc group open to people from industry and government who are responsible for managing contaminated sediments. The group was formed in 1998 and is dedicated to using sound science and risk-based evaluation of contaminated sediment management options.

SMWG contracted with a number of people to write technical papers addressing sediment management issues. Three of the papers written by SMWG addressed natural recovery, either directly or indirectly. These papers were (1) The Role of Natural Attenuation/Recovery Processes in Managing Contaminated Sediments, (2) Using Natural Processes to Define Exposure from Sediments, and (3) Sediment Stability at Contaminated Sediment Sites. At the last Action Team meeting in San Diego in January 2000, Jensen suggested that the Action Team conduct a technical review of the SMWG papers.

Davis said he would coordinate the logistics of identifying willing participants for the Subgroup. Davis will schedule conference calls, beginning in May 2000, to begin the technical review of three SMWG papers on natural recovery. During these calls, the group will conduct a critical review of the papers, identify technical gaps and weaknesses, and provide suggestions for addressing or filling these gaps. Initially, reviews will be written for the SMWG and the paper authors. In the more distant future, the Subgroup will write white papers like those written by the Assessment Subgroup, discussing issues identified during the review of the SMWG papers.

Davis requested that any volunteer Subgroup members contact him.

Ken Finkelstein asked for clarification about SMWG's membership. Davis replied that SMWG is composed mostly of site owners, such as DOD or private parties, with sediment contamination issues. This is a group for potentially responsible parties, not regulatory agencies.

An audience member asked about Davis's long-term objectives for the papers produced by the Subgroup. Davis said the papers will not be guidance documents. They will address technical issues associated with natural recovery. The papers will discuss available remediation approaches, identify successful or unsuccessful methods, describe points to consider, detail current approaches, and compare sampling methods.

Timberlake said there will be political sensitivities to consider if an Action Team subgroup provides comments to SMWG. Members of SMWG met with EPA to discuss these papers prior to publication. Comments provided to SMWG may be misinterpreted. Davis said the reviews are not meant simply to criticize the SMWG papers. Rather, the technical review will serve as a springboard to identify areas for the RTDF by identifying data gaps, questions to answer, and issues to address. For example, Davis noted that the papers did not discuss the biological aspects of natural attenuation. The Subgroup could address this topic.

PROMISING TECHNOLOGIES
Richard Jensen, DuPont Corporate Remediation

Jensen discussed two types of sampling probes that are being used by Sam Kounaves at Tufts University and George Luther at the University of Delaware. (Jensen's presentation materials are included as Attachment E.) Jensen said that Kounaves, who spoke during the January 1999 Action Team meeting, has conducted studies using an electrochemical probe. (Most of his studies have focused on ground-water contamination.) Jensen said that this probe can test for 30 metals, including copper, cadmium, lead, and mercury. Jensen encouraged Kounaves to study sediment porewater using this probe.

Jensen said that Luther is developing deployment equipment and using the Lander probe. The deployment equipment is a heavy, open box with a device in the middle to hold several probes. This box is dropped over the side of a boat to the water body floor. The device that holds the probes can be maneuvered to allow for very precise sediment analysis. The Lander probe consists of a gold wire flame-sealed in a glass tube. The probe has a 0.25-millimeter resolution. Luther has used this probe to assess undersea blow holes; he deployed the probe at Sandy Hook in Delaware to measure oxygen, manganese, iron, sulfur, and pH. A summary of the Sandy Hook study was published in the December 1999 issue of Environmental Science & Technology. The probe can also test for mercury using a two-step process. Luther's research focus has been natural environments, not contaminated ones.

PROPOSED FORMAT FOR NEW MEETINGS
Richard Jensen, DuPont Corporate Remediation

Since September 1998, Jensen said, the Action Team has held five general meetings, including the May 2000 meeting. During these meetings, he said, presentations have been given on a wide variety of topics. He proposed changing the format for future Action Team meeting so that each is devoted to covering just one topic. (Jensen's presentation materials are included as Attachment F.) (He proposed the following as potential topics: in situ electrochemical methods, confined disposal facilities as reactors, accounting for sediments in the total maximum daily load, groundwater/sediment interactions, and in situ treatment approaches.) Jensen said that the meetings could follow a workshop format, where several short presentations would be given and then a brainstorming session would be held. A summary of each meeting, Jensen said, could be posted at RTDF's Internet site and published in the RTDF Update.

Jensen noted that the Action Team's Assessment Subgroup is already planning to meet in September 2000. He suggested holding a one-day Action Team workshop on electrochemical probes in conjunction with this meeting. He said that the meeting could begin with an introduction and an objective statement. This could be followed by three or four 30- to 45-minute lectures. (Kounaves and Luther could be asked to speak during this time. Then, a 2-hour brainstorming session could be held, followed by a 1-hour session focusing on developing a collaborative plan.

Jensen asked if audience members thought that the proposed meeting format was a good idea. Audience members agreed that having longer discussions about a single topic was a good idea. They also agreed that inviting speakers from beyond the Action Team membership could broaden their interactions with other scientists. (One audience member, however, cautioned against inviting speakers who are seeking funding.) Action Team members agreed to test the proposed format at the next meeting. One audience member suggested that Jensen send Action Team members a survey to identify the main topic of interest for a workshop. Jensen agreed to send a list of possible workshop topics to Action Team members.

Before closing on this discussion, one audience member expressed some reservations about the new format, noting that the initial meeting format was selected so that Action Team members could search for topics of interest. If the meetings become workshops, they will serve as educational forums instead. The attendee thought that the Action Team should assess their needs and purpose before deciding to abandon the current meeting format.

Attachment A: Final Attendee List

RTDF Sediments Remediation
Action Team Meeting

Crowne Plaza Cincinnati
Cincinnati, Ohio
May 8, 2000

Attachments B through F

Attachment B: The Superfund Innovative Technology Evaluation (SITE) Program (Annette Gatchett)

Attachment C: Paleta Potential Capping Site (Sabine Apitz)

Attachment D: Natural Recovery Subgroup (John Davis)

Attachment E: Promising Technologies (Richard Jensen)

Attachment F: Proposed Format for New Meetings (Richard Jensen)