Impact/Purpose:

The objective of the proposed Hazardous Substance Research Center/South and Southwest (HSRC/S&SW) is to provide basic and applied research, technology transfer and community outreach that address hazardous substance problems, especially the engineering management of contaminated sediments and other problems of special interest to communities within EPA Regions 4 and 6. Due to past and present toxic releases, these regions face serious hazardous substance problems and yet contain a significant fraction of the wetlands and inland waters found in the United States. The mission of the Center is to be a primary provider of the tools and process knowledge required to resolve problems posing the greatest risks to people and the environment.

Description:

The specific activities within the Center-supported research program are detailed in separate reports that are included herein. An updated list of all Center publications is also attached. Specific projects conducted by the Center included

• Contaminant Release During Removal and Resuspension, Mason B. Tomson, Louis J. Thibodeaux, and Amy T. Kan, with Rice University, TX and Louisiana State University, Baton Rouge, LA.
• Bioavailability of desorption-resistant contaminants, Danny D. Reible and John W. Fleeger , University of Texas and Louisiana State University
• Phytoremediation in wetlands and confined disposal facilities (CDFs), Dr. John H. Pardue, Dr. William Moe, Louisiana State University
• In-situ Containment and Treatment: Engineering Cap Integrity and Reactivity, Joseph B. Hughes, Kalliat T Valsaraj, Georgia Institute of Technology and Louisiana State University
• Structure-Performance Relationship for Bentonite-Cement Composite as a Material for in-situ capping of contaminated underwater sediments, Mark R. Wiesner, Rice University
• In-Situ Containment and Treatment: Engineering Cap Integrity and Reactivity, Billy L. Edge, Texas A&M University

“Contaminant Release During Removal and Resuspension” focused on the metals release from sediments resuspended as a result of dredging or storm events. More than 99% of the AVS is oxidized in 6 days of aeration. It is clear that the resuspension of anoxic sediment in oxic waters not only induces heavy metal release to the aqueous phase, but alters their binding form in the sediment as well. Zn, Pb, Ni, Co, and Cd transformation from strongly bonded species (oxidic, cabonatic, sulfidic) to more weakly bonded species (exchangeable) would increase the mobility and bioavailability of these metals in the aquatic environment. Over extended periods of dredging, the change in binding forms of the solid phase is likely a bigger concern than that in the solution phase. A new bioavailability test for heavy metals was developed and the test was used to determine the bioavailability of Anacostia sediment during resuspension. As shown in the previous results, the aqueous phase heavy metal can be readsorbed onto the newly formed ferric oxyhydroxides. Therefore, a conventional test, e.g. DRET, will not be adequate to measure the bioavailability of heavy metal during dredging. The proposed test allows for the resin to be in direct contact with the sediment and therefore a better assay to quantify the bioavailability of heavy metal.

“Bioavailability of desorption-resistant contaminants” was designed to evaluate the bioavailability of the desorption-resistant fraction of hydrophobic organic contaminants using uptake and accumulation in tubificid oligochaetes. The results of the experimental program support the view that measurements or predictions of porewater concentrations can predict steady state uptake of partitioning hydrophobic organic contaminants such as PAHs and PCBs in tubificid oligochaetes. That is, measures of physicochemical availability can be used directly to predict bioavailability. This was observed regardless of whether contaminant exposure was primarily by absorption from porewater (as with less hydrophobic compounds such as phenanthrene) or by absorption from ingested sediment (as with more hydrophobic compounds such as pyrene or benzo[a]pyrene). The kinetics of uptake were much different in the two scenarios but the steady state accumulation was still governed by measurements of porewater concentrations. It is postulated that organisms cannot accumulate more contaminants than predicted by thermodynamic equilibrium with porewater regardless of route of exposure. In summary, the effects of partitioning organic compounds on at least the benthic organisms studied are not correlated with bulk sediment concentration because desorption resistance and limited availability. This suggests that regulatory standards based upon porewater concentrations would be more indicative of potential exposure and uptake in these organisms.
“Phytoremediation in wetlands and confined disposal facilities (CDFs)” was designed to develop a scientific basis for a plant-based remedial approach for sediments contaminated with chlorinated organic compounds. The objectives of the proposed study were to:

• Define the biodegradation potential of chlorobenzenes and chlorinated solvents by quantifying biogeochemical conditions in the rhizosphere. Key conditions include the specific detrital decomposition products (organic acids and hydrogen) and microbial populations that develop on and adjacent to the plant root.
• Define other potential fate mechanisms: plant uptake and volatilization by studying the dynamics of plant uptake of chlorobenzenes in wetland sediments.

Two hypotheses were supported by the research

• By vegetating sediment contaminated with chlorinated organic compounds, below ground root matter will serve as source of H2, overcoming redox potential limitations in sediments
• Reductive dechlorination is enhanced in vegetated sediments because the root surface serves as a location of enhanced activities of dehalorespiring and other degrading microbial populations

The research is expected to provide support for the wetland management of refractory chlorinated contaminants in sediments (e.g. in confined disposal facilities).

“In-situ Containment and Treatment: Engineering Cap Integrity and Reactivity” was designed to evaluate the effects and potential of biologically active caps. The purpose of reactive caps is to remove contaminants from the aqueous phase during transport through the cap, theoretically eliminating break through into the overlying water. Thus, unlike a traditional sand cap, they can be applied at sites subject to advective flow. To date, the development of reactive caps has focused on physicochemical methods of contaminant removal such as abiotic reactions or sorption. One limitation of such physicochemical reactive caps is that they are subject to fouling (abiotic and biological), which can reduce reactivity with time. A second limitation of physicochemical reactive caps is that they inherently possess a finite capacity for reaction/sorption, creating the need to replenishment of the reactive/sequestering material over time to maintain reactivity. The development of a reactive cap that can continuously treat mobile contaminants would eliminate the risk of contaminant break through due to loss of reactivity, decrease the possibility of contaminant resuspension during maintenance operations, and potentially lower treatment costs. The emplacement of microorganisms capable of contaminant biotransformation within a cap provides an opportunity to meet this need. The project focused on the evaluation of transport, reactivity and fate of chlorinated solvents, for example, as in a contaminated groundwater plume intersecting a river bottom. The work showed that a cap can be an effective biological reactor although delivery of appropriate nutrients or amendments to maintain the reactivity at high rates may not be feasible. The work also examined the effects of gas generation as a byproduct of biological activity and the implications of gas migration for contaminant release. The results showed that very high gas generation rates would generally be required for significant contaminant migration.

The final two projects, “Structure-Performance Relationship for Bentonite-Cement Composite as a Material for in-situ capping of contaminated underwater sediments” and “In-Situ Containment and Treatment: Engineering Cap Integrity and Reactivity”, examined the stability of a conventional cap under extreme storm event forcing and technologies for stabilizing a cap with a bentonite cement. A two-dimensional (2D) parallel model of hydrodynamic and sediment transport coupled with a wave model was used to study cap stability. A two-dimensional hydrodynamic model is used to calculate the water circulation within the bay. The hydrodynamic model is based on the two-dimensional (2D) parallel version of Advanced Circulation ((P)ADCIRC) Hydrodynamic Model (Luettich and Westerink, 2002), with extended Sediment Transport module. The sediment transport module in ADCIRC applies suspended sediment transport for both cohesive and non-cohesive type of sediment. An example application of the extended ADCIRC2D Transport coupled to SWAN was assessed in an actual estuary, Matagorda Bay, Texas and used to evaluate stability of a conventional sand cap during a major storm event, that of Hurricane Carla (1961). Although the Bay was largely depositional, the model was capable of predicting erosion up to 30 cm in isolated areas, potentially compromising an unarmored cap in those areas.
“Structure-Performance Relationship for Bentonite-Cement Composite as a Material for in-situ capping of contaminated underwater sediments” The objective of this work was to create sediment caps, tailored for strength and semi-permeable properties, from bentonite/cement composites. Carious cap microstructures were created by controlling post-depositional chemical processes in a cap. By judiciously choosing cement/bentonite and liquid /solid ratios of the composite, desired transport and mechanical properties of the reactive barrier may be attained. Controllable permeability and the capacity of cementitious materials to bind heavy metals make such barriers especially attractive. Bentonite/cement composite was proposed as a new capping material for the isolation of contaminated sediments. By controlling post-depositional chemical processes in a forming composite it is possible to arrive at different cap microstructures leading to different mechanical and transport characteristics of the capping layer. Cement fraction and the extent of hydration of the composite appear to be the most important factors determining the overall performance of the cap.
In addition, the research program has seen application at a number of sites. The Center has attracted outside research funds to:

• Conduct a demonstration program on active capping in the Anacostia River, Washington DC
• Evaluate the fate and transport of mercury in contaminated sediments with specific application to Pompton Lake, NJ
• Evaluate the feasibility of capping very soft, NAPL containing sediments with specific application to a site in Lake Charles, LA
• Evaluate organoclay as an active capping media for the control of NAPL contaminants in support of the Oregon DEQ’s efforts to remediate the McCormick and Baxter Creosotes Site in Portland, OR
• Evaluate biodegradation in sediment caps in Onondaga Lake, Syracuse, NY
• Conduct an Advanced Research Workshop supported by the North Atlantic Treaty Organization held in May 2005 on the Assessment and Remediation of Contaminated Sediments.

These programs are in addition to the a variety of projects attracted by individual investigators in the Center that build upon the research products of the Center but are administratively monitored outside of the Center. Many of the investigators within the Center are also routinely asked to apply their expertise to provide advice on remedy evaluation and selection at a variety of contaminated sediments sites. In this capacity, we generally provide advice for the lead party which may be the responsible party or federal or state regulators. A partial list of specific sites where Center personnel have been asked to provide insight and support over the past year include

• Neponset River, Boston, MA
• Onondaga Lake, Syracuse NY
• Welch Creek, Martin County NC
• Grasse River, Massena NY
• Fox River, Green Bay WI
• Hudson River, Hastings NY
• Thea Foss Waterway, Tacoma WA

The research program is complimented by a technology transfer and outreach effort focused nationally on contaminated sediments and their management but regionally with respect to the broad range of hazardous substance issues that impact communities in the south and southwest. The technology transfer efforts disseminate the research advances of the Center via both print and electronic media. An up-to-date summary of the Center, including reports and other broader interest publications, can be found at http://www.hsrc-ssw.org/ . The outreach efforts focus on providing environmentally troubled communities in the region technical assistance to enable them to better understand and participate in decisions being made about their hazardous substance problems. The outreach activities are driven by local concerns which often include visible problems in the air and soil and rarely driven by relatively low visibility sediment problems. The outreach programs have benefited 22 communities iin Region 4 and 19 in Region 6 over the period of the grant. The outreach programs include both the Technical Outreach Services to Communities (TOSC) (described separately herein) and a Technical Assistance for Brownfields (TAB) program (detailed in a separate report). Our TAB program was significantly expanded in this funding year by receipt of a grant to support direct assistance to communities as well as research activities that seek to guide Brownfields response efforts that extend beyond a single community.

URLs/Downloads:

reible.html

2002 Progress Report

2004 Progress Report

Final Progress Report

2003 Progress Report

Record Details:

Record Type:PROJECT( ABSTRACT )

Start Date:10/01/2001

Completion Date:09/30/2006

Record ID: 54018

Show Additional Record Data

Related Organizations:

Role :OWNER

Organization Name :GEORGIA INSTITUTE OF TECHNOLOGY

Organization Name :HSRC (2001) - SOUTH AND SOUTHWEST

Mailing Address :225 North Ave

Citation :Atlanta

State :GA

Zip Code :30332



Role :OWNER

Organization Name :TEXAS A & M UNIVERSITY

Organization Name :HSRC (2001) - SOUTH AND SOUTHWEST

Citation :College Station

State :TX

Zip Code :77843



Role :OWNER

Organization Name :RICE UNIVERSITY

Organization Name :HSRC (2001) - SOUTH AND SOUTHWEST

Mailing Address :6100 S Main

Citation :Houston

State :TX

Zip Code :77005



Role :OWNER

Organization Name :LOUISIANA STATE UNIVERSITY - BATON ROUGE

Organization Name :HSRC (2001) - SOUTH AND SOUTHWEST

Mailing Address :Louisiana State University

Citation :Baton Rouge

State :LA

Zip Code :70803

Project Information:

Approach :

The Center will consist of Louisiana State University, as lead institution, Georgia Institute of Technology, Rice University, and Texas A&M University. The core institutions will be assisted in these endeavors by personnel from Southern University and Howard University. In addition, in recognition of the importance of a local perspective in successful community outreach efforts, we have established partnering agreements with a wide variety of universities and organizations throughout the south and southwest regions. The broad range of expertise available to the research and outreach teams will insure our ability to be truly community and problem driven.

The research themes of the Center include 1) assessing the physical, chemical and biological availability of contaminants in sediments, 2) evaluating and enhancing biotransformation processes in sediments, and, 3) improving the science of risk management for contaminated sediments. The overriding objective is to improve the effectiveness of remedial approaches by seeking to understand and minimize contaminant release and exposure. Toward this end, four research projects have been identified, subject to review and approval of a Scientific Advisory Committee. These projects seek to 1) evaluate the bioavailability of desorption resistant contaminants, 2) develop improved approaches for in-situ containment and treatment, 3) assess contaminant losses during removal and episodic storm events, and, 4) evaluate phytoremediation for remediation in wetlands and confined disposal facilities (CDFs).

The research program will be complimented by a technology transfer and outreach effort focused nationally on contaminated sediments and their management but regionally with respect to the broad range of hazardous substances issues that impact communities in the south and southwest. The technology transfer efforts will disseminate the research advances of the Center v

Cost :$5,550,000.00

Project IDs:

ID Code :R828773

Project type :Center