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

Waterways Experiment Station
Vicksburg, Mississippi
October 29, 1996

To begin the meeting, a request for volunteers to discuss and share their experiences with the remediation of contaminated sediments. Below are the perspectives from Industry, the Navy, and EPA.

Brad Cushing, Applied Environmental Management, Inc., Malvern, PA:

• Brad is a consultant (Applied Environmental Management, Inc., Malvern, Pa) for General Electric (GE) and other companies.
• Involved in review of sediment remediation efforts— to identify how effective, difficult, and expensive the approaches were. The review focused on who has done it and what they did. Information on this type of data is difficult to obtain; this review was pulled from a variety of sediment cleanups.
  • Triana/Tennessee River: DDT—diverted stream and revegetated.
  • James River: no action—contamination diffuse, and opted for natural recovery. Action level has been met in the interim.
  • Sangamo-Weston, SC: a model predicted meeting Food and Drug Administration (FDA) action levels in 12 years by natural attenuation—this option followed.
• Despite widespread “publicity,” there are only about a dozen sites at which sediments have been remediated or a decision not to remediate has been made, for example:

• About 40 sites total in the U.S. Of these, 23 are being tracked; the following is a summary of those under action.
  • Alcoa site—1-acre hot spot, dredged material taken to onsite landfill, water discharged back into the Grasse River. Rocks had to be decontaminated and sent to landfill. Continue to monitor for environmental benefit.
  • Sheboygan site—15 hot spots, about 5 million yd³ by a bucket excavator on barge. Continue to monitor for environmental benefit.
  • Ruck Pond site—1000-ft stretch, Cedar Creek, drained pond, removed sediment to bedrock, PCBs, 95-99 percent removal was the target. No sampling done after work completed. Mercury Marine was the potential responsible party (PRP).
  • New Bedford Harbor site—Aerovox and Conell-Dublier were the PRPs. Estimated more than 1 million yd³ with concentrations of 1 ppm or more of PCBs. Agreed to use a dredge approach to remove a 45-acre hot spot. Moved contaminated sediment to another point to hold while awaiting treatment technology. Originally wanted to incinerate material but public objection stopped this. Found that the water treatment facility was the rate limiting step. The dredging operation could use 24 hours of treatment capacity after 6 hours of dredging.
  • GM Messina site—St. Lawrence, 10 million yd³ rocks and 15 million yd³ sediment. Used excavator. Rocks cleaned and put back. Used sheet piling to isolate area since silt curtains failed the first time. Divided area into 6 quadrants, remediated one at a time; put sediments and water on site for treatment. Could not get to 1 ppm target level, even after repeated effort. Decided to use 3 ppm target, average. Areas where 25 ppm found on average, allowed capping.
  • Waukegan Harbor site—10 acres on Lake Michigan; no verification of effort. Dredge to sand layer should get 90 percent of materials. Capped at the end of effort.
  • Black River site—2 hot spots, 60 million yd³, landfilled.
  • Marathon Battery site—tidal estuary; dredged 10 million yd³, 67 million yd³ from another part.
  • Bayou Bonfouca site—dredged and water discharged back to estuary. Specially designed bucket; $115 million spent on remediation.
• Conclusions:
  1. Costs probably do not include treatment.
  2. No clear dredge-type preference.
  3. Debris and rocks can be problematic for certain dredging types.
  4. Seven of the sites could use nearby PRP site as a beach head for sediment staging.
  5. Great variability in target levels; emphasizes importance of assessment.
  6. Target cleanup levels were not achieved at 3 of the 9 sites; difficult to achieve good cleanup levels with dredging.
  7. Many of the sites did not use any confirmatory sampling after dredging.

Victoria Kirtay, Space and Naval Warfare Systems Command (SPAWAR):

• Main focus on San Diego Bay.
• Overview of Naval Research and Development (NRAD) research areas.
• Developed Trace Metal Analyzer for field work.
• Map sediment contaminants, contaminant budgets.
• Database development for SDB - good study site.

Karen Miller, Naval Facilities Engineering Services Center (NFESC):

• Environmental Security Technology Certification Program (ESTCP) - emphasis on full scale demonstrations at Department of Defense (DoD) sites. Agencies encouraged to partner with private industry. Mentioned partnering/funding mechanisms under Navy’s programs.
• Topics of interest include both sediment and soil technologies that can be applied to sediments.
• National hydrocarbon test location which is used for scale testing.
• Wetlands and other areas can be used for demonstration projects.

Dennis Timberlake, U.S. EPA National Risk Management Research Laboratory (NRMRL):

• Described EPA/NRMRL efforts. Recently obtained $1 million for in-house research on sediments—in situ treatment, treatment within a disposal facility, ex situ treatment of sediments, part of larger group now called Ecosystem Restoration. SITE program on the Calumet River.
• Question to the audience: Should NRMRL focus discussions on a certain category of contamination (e.g., PAHs, PCBs, planar PCB/dioxin, metals [H, Cd, Pb versus Ni, Cu, Zn], pesticides)? High- versus low-level contamination? Confined Disposal Facility (CDF) versus real in situ?

The participants broke into three subgroups during the meeting. The subgroups focused on assessment, in situ treatment, and in situ capping. Below are each of the group’s general discussions

Assessment Subgroup

Participants:David Hohreiter, BBL, Inc.; Jim Leather, Navy Research and Development Center; David Moore, WES; Doug Gunnison, WES; Ralph Stahl, DuPont

General Discussion Concerning Issues Previously Identified (see Appendix A):

• Include microbial community structure and function to the biology component.
• Hinge on assessment endpoint - examples given had no indication of what the endpoint driving the action was.
• Some of the assessment tools lead you to a clean up level that is not achievable.
• We should work towards goals that are achievable, risk-based.
• Could we develop a framework that could have general applicability for approaching assessment at all sites?
• Should consider what we do with sediments placed on land and how the assessment would change given this disposal option.
• What are the criteria for deciding when the natural remediation option is best?
• Transport of material is another consideration when active remediation occurs.
• How do we assess the impact of any movement of the compound, even at very low levels? Could we use this as a flag of effect?
• Framework may be too loose; need a more defined process. Regional differences in values also may force inconsistencies in approaches.
• Natural attenuation does not mean “do nothing.” You may need to monitor the site and other aspects. For that reason it may not always be the cheapest alternative. A framework would have to be flexible enough for looking at the various remedies.

1. How do we define assessment for the purposes of this RTDF Team?

• We will use the human and ecological risk assessment paradigms in our approach. Assessment includes evaluating the hazard, stress, and exposure resulting from sediment associated contaminants. Input information includes, but is not limited to, toxicity, transport, and the ability of the sediment (biotic and abiotic) to naturally attenuate the contaminants.

2. General Capabilities/Interests - What We Could Bring to the Table:

• Navy Research and Development (NRAD) Center can explore bringing a current or future marine base remediation and closure (BRAC) site, sediment chemistry and biological testing, screening capabilities, and eco-risk modeling. Could overlay some additional assessment efforts on top of one that is currently underway in a RI/FS or similar effort.
• Waterways Experiment Station (WES) could apply new techniques that are being developed internally to a site, including chronic sublethal effects testing; understanding population level impacts through population models.
  • Couple population models that, with field studies and data, could use existing contaminant database to view the contaminant under study.
  • Have a project to develop biomarkers for dioxin exposure.
  • Apply microbial community structure and function analyses for impacts on biogeochemical cycles and the ability of the community to degrade (catabolic ability) the compound, sorption/desorption of contaminants to sediments.
  • Leverage project on natural attenuation. Use microbial processes to help understand natural attenuation; develop trophic transfer models.
• DuPont can bring ability to conduct toxicity testing of freshwater sediments and learnings from soil remediation research.
• BBL has good background information on PCBs in freshwater systems (Sheboygan, GM, Ruck Pond, Housatonic work done for several PRPs). Data not easily released due to regulatory constraints.
  • Understand options for remediation including active remediation and natural attenuation.
  • Interest in risk assessment and all aspects of what occurs during the remediation, including risk management, etc.
  • Would like to provide a checklist or approach to the entire remediation project.
  • Would be capable of talking to clients and see if data are releasable.
• Principles for using measurement tools.
  • bioassays
  • chemistry
  • models—fate, population
• Need a reference site and that will be used to make comparisons as to whether there has or has not been an effect. Population models may be used in conjunction with sediment toxicity testing; can be a better assessment tool than making arbitrary comparisons to reference sites.

General Efforts If We Had a Site to Work On:

• Use a tiered approach.

1. Problem Formulation

• Establish assessment endpoints including receptors.
• Obtain preliminary understanding of the contaminants of concern.
• Understand risk management options, goals, etc. - could eliminate certain remediation options which will also narrow the scope of the effort.
• Consider potential reference site(s).
• Develop site conceptual model - includes ecological and human receptors.
  Understand pathways, human and ecological exposure.
  Understanding the system under study.
  Obtain background and historical information - sediment chemistry.
  Distribution of contaminants - horizontal and vertical.
  Understand fate of material - actively being degraded or not by system

2. Analysis

• Establish sampling plan, data collection and analysis - tiered approach. Consider grid with some statistical discussion.
• Screen for both exposure and effect.

3. Pre-Post Remediation Actions

• Sampling to determine level of removal, pre remediation, post remediation (on site and where it goes). Monitoring plan for post remediation. Restoration plans.

Put forward Items

• Who else should we contact? Have we contacted the right people?
  • May be some leveraging opportunities with Coastal Wetland Protection and Restoration Act (CWPRA) group.
  • Simian Hahn - Navy - Philadelphia, Pa
  • Randy Wentsel - Army - Aberdeen, Md
  • Other Corps Districts

In Situ Treatment Subgroup

• After some discussion, Karen Miller (NFESC) and Dennis Timberlake (EPA/NRMRL) indicated willingness to assume some greater roles as leaders of this group.
• Dick Jensen (DuPont): More successful RTDF Teams have identified limited number of topics to focus on and perhaps this team could do the same, such as selecting sites to demonstrate several remediation approaches and perhaps sites that will be focus.
• Karen explained that the Navy has facilities and access to sites.
• Contaminants of greatest interest, according to several participants.
  • Lead and PAH from shooting ranges are major issues as well as chlorinated solvents.
  • Highly chlorinated organics seem to be an important problem; resistant to degradation.
  • Karen noted that Heavy end PAHs do not seem very amenable to degradation. cited work in Houston Ship Channel regarding biodegradation of PAHs.
  • DuPont is more focused on metals than on organics.
• Possible emphasis on treatment within a Confined Disposal Facility (CDF).
  • Karen stated that Canadians seem to be moving ahead in this area. Found example of chemical (nutrient) application in sediment treatment.
  • Waterways Experiment Station (WES): Focused more on CDF, because dredging is primary focus, not an alternative.
  • Dick noted that the Dutch have been bringing dredged material into disposal facilities and performing electrolysis to remove metals from sediments. Louisiana State University (LSU) and Massachusetts Institute of Technology (MIT) are centers for electrokinetic research. Also doing a lot of soil washing; fines from soil washing are much like sediments. Electrokinetics better for adsorbed lead rather than particulate lead. Also potentially good for relatively soluble organic compounds because of bulk water movement.
  • How to optimize design and operation of CDF for treatment was discussed.
  • Idea of designing sediment treatment facility for long-term (e.g., 5-year) treatment followed by removal. Allowing site to be an ongoing site for disposal and subsequent treatment.
  • Dredge disposal options are 20 years old and need to be modernized. Turning CDFs into treatment CDFs is a logical direction. Driving forces, i.e., U.S. Army Corps of Engineers, need economical disposal options.
• Dick stated that he wanted to remain open to ex situ treatment. DuPont has operations pending on 0.5 million yd³. Desire remediation technologies that are big, slow, and cheap.
• Focus on slow treatment of materials as contaminants desorb from sediments. Do not have to worry about material that is so tightly bound as to be unavailable for treatment. Need to focus on public awareness of “slow is better” types of problems. Need scavenging types of approaches to deal with recalcitrant chemicals. DuPont produces pellets of NOMEX polymer, porous substrate good for bacterial breakdown. Stabilization well accepted for metals; for organics, the level of comfort decreases. What techniques could be used to supplement control for escapees?
• Dave Mount (EPA/ORD) presented the possibility of enhancing sulfide production.
  • Dick noted RTDF’s In-place Inactivation and Natural Ecological Restoration Technologies (IINERT) Soil-Metals Team is looking at phosphate binding for lead.
• Dick presented the possibility of introducing materials while sediment is in the pipeline, e.g., adding zero-valent iron as part of the lay-up. May dechlorinate PCBs very slowly, though reaction rate may not be very important in the big picture.
• Karen noted that bioremediation of PAHs is possible theme.
  • PAH bioremediation: 2- and 3-rings doing well; higher rings not doing well. Uncertainties about availability. Anaerobic degradation looks like may have some promise, but there is controversy over technologies.
  • Oxygen transfer: Critical for land-based aerobic degradation. Dredge material seems to have high oxygen demand. Only way identified is to spread over large area, allow to vegetate and convert to soil, establishing an aerobic zone.
• What about phytoremediation?
  • Scott Cunningham stated that DuPont is champion for phytoextraction of metals. Dick Lees is active in phytoremediation. Kathy Banks at Kansas State University is also active.
  • Karen noted that Kathy Banks is going out to Port Hueneme to do phytoremediation studies. Could build additional cells to evaluate other technologies (e.g., PAH- contaminated sediments).
  • Karen (NFESC), WES, and DuPont are looking at small (50-foot) plots. DuPont is interested in providing consulting expertise.
  • Estuarine sediments are high in sulphur; need remediation to make dredge material into suitable soil. Usually takes years, but could be accelerated.
  • Any approach that brings sediments above the water has a need for good vegetation management.
• Should not forget about in situ stabilization; although off-the-shelf technologies are probably not available.
• Constructed wetlands: DuPont is member of IINERT RTDF Team which is involved in this area. Possibility of using constructed wetlands to treat hydraulically pumped material into CDFs.
  • Transfer of information: Probably potential for a lot between dredge material management and constructed wetlands areas.
• Geotextile bags: Designed to retain dredged material and release water. Possibility of adding a sorbent component to enhance effectiveness of bags relative to contaminants.
• Dick stated that it is difficult for any technology to cost compete with “no action.” Maybe we should be evaluating whether doing nothing is adequate.
  • Enhancing natural process may be an appropriate focus for the groups. For example, Hamilton Harbor evaluated chemical fertilization for enhanced biodegradation in Canada.
• Dennis noted that NRMRL has individuals interested in almost all contaminants and technologies. Possibility of a “cook off” with set of standard sediments.
• Possibility of issuing an Request for Proposals (RFP) for innovative approaches.
  • Dennis stated that the innovative technologies portion of EPA’s Superfund Innovative Technology Evaluation (SITE) program encourages proposers to develop bench-scale ideas to pilot stage.
  • Canadians have had similar solicitation, but projects that went to pilot scale were more traditional approaches. Perhaps an indication of how many effective and innovative technologies are available.
  • Perhaps define 2 or 3 areas that will be a focus for the groups; then broadcast a solicitation in those areas, i.e., re-recruit.
• Finally, several approaches were identified that the group could possibly focus on:
  1. Electrokinetics
  2. Phytoremediation
  3. Introduction of chemical additives into CDFs to initiate or enhance degradation reactions

Capping Subgroup

In Situ Containment/Capping

• Strategy in support of containment as a viable option.
• Enhanced cap design.
• Improved predictive/design tools.
• Field verification of capping effectiveness.

Strategy in Support of Containment

• Define possible objectives for in situ capping.
• Technical basis for why capping works.
• Lack of technical basis for why capping would not work.
• Proper perspective with other events, residual options.
• Economic advantages of capping with specific examples.
• Possible design for mitigation/enhancement.
• All options evaluated on a consistent technical basis.
• Risk-based assessments.

Enhanced Cap Design

• Smart cap design.
• Innovative features.
• Self-maintaining caps.
• Features for long-term containment capacity.
• Self-monitoring caps.
• Ancillary features to enhance integrity.
• Cap features for environmental enhancement/habitat value.

Improved Predictive/Design Tools

• Placement techniques to avoid re-suspension/displacement.
• Improved consolidation prediction.
• Improved tools for evaluation of flux (advective and diffusive).

Field Verification of Capping Effectiveness

• Controlled field site.
• Verification of physical integrity.
• Protection from extreme events.
• Precise layering.
• Conventional data collection methods.
• Smart cap features for data collection.
• Multi-year timeframe.

Appendix A

Assessment Issues - Group Input on July 31, 1996

• Developing risk-based goals, cleanup measures.
• Developing cleanup goals, numbers, and approach.
• Assessment tiers, triggers.
• Understanding impacts and benefits to the environment, ecological costs of “active” remediation. Acute, longer-term, recovery, endangered species.
• Still lots of data gaps in our understanding risks, benefits.
• How do we define success? (know that the assessment reflects actual conditions and that there is or is not risk, and/or the remediation has improved the situation)
• Mechanism of chemical sequestation.
• Decisional matrix, weight of evidence (how do we weigh the individual bits of data? Is one more important than another?)
• How do we define risk?
• Test methods?
• Interpretation of test data - guidance. Separate bioaccumulation from toxicity. Interpretation may be influenced by the decision that is needed. Also influence of physical characteristics of site.
• Find little site-specific toxicity data. How to use site-specific toxicity data, need guidance and protocols.
• How do we factor in multiple contaminants into the risk assessment, or risk management decision?
• How do we handle multiple sources of contaminants? Non point sources?
• How do we determine actual cause of toxicity? Conduct a TIE or other test?
• After remediation of a particular contaminant we expose another - how do we handle that?
• Scale-up of lab effects to field situation? Extrapolation?
• Extrapolation of EqP to higher level impacts - food chain analysis.
• Identification of appropriate exposure unit for ecological effects - harbor or other unit?
• How do we define acceptable risk - no benchmark for ecological.
• How do we use mitigation options vs on-site remedial actions? Better communication about options with scientists in regulatory and private sectors.
• What is an appropriate reference sediment?
• Keep it simple - the assessment...but still need to understand cause where possible.
• Problem where assessment was not tied well to remediation.
• Communication gap between R&D community in EPA and Program Offices.
• Role of public perception driving remediation - for or against the action. How can this be handled? Improve communication with non-technical community.
• Develop “user-friendly” communication tools for risk management, showing costs, benefits, etc. that are understandable.
• Models for understanding recovery time.
• Potential for other endpoints to be used in sediment assessments (genotoxocity in Environment Canada).

Assessment Sub-Team

I. Common approaches previously used in sediment bioassessment

1. The Sediment Quality Triad
   
   
   
2. Effects based approach
   Toxicity—Biology—Decision
3. Numerical criteria approach
   AET, ER-L, ER-M, EPA, States

II. The EPA Framework for Ecological Risk Assessment