Evaluation of Placement and Effectiveness of Sediment Caps

EPA Grant Number: R825513C009
Subproject: this is subproject number 009 , established and managed by the Center Director under grant R825513
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - South and Southwest HSRC
Center Director: Reible, Danny D.
Title: Evaluation of Placement and Effectiveness of Sediment Caps
Investigators: Reible, Danny D. , Thibodeaux, Louis J. , Valsaraj, Kalliat T.
Institution: Louisiana State University - Baton Rouge
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 1995 through January 1, 1997
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Hazardous Substance Research Centers , Land and Waste Management


The project had the overall objective of evaluating and overcoming certain potential limitations of capping in the areas of cap placement technologies and long-term cap containment effectiveness. The specific objectives are outlined below.

Cap Placement Technology
The objectives of this portion of the effort was improved guidance on the selection of cap placement technologies and model tools for the evaluation of contaminant losses that occur during cap placement and during subsequent cap consolidation. Cap placement techniques evaluated include point dumping from the water surface, application with a diffuser near the sediment-water interface, and sediment broadcasting. The need for and the effectiveness of geotextile placement prior to cap placement was also assessed. Post-placement consolidation and the resulting contaminant losses were also evaluated and compared to laboratory consolidation measurements and the predictions of mathematical models.

Long-Term Containment by a Cap
The objective of this portion of the effort was to evaluate loss of containment caused by advection and random penetrations or localized cap failures. Potentially important advective processes include porewater expression during consolidation, groundwater seepage, and gas migration.


The laboratory experiments were used to evaluate the mobility of several contaminants in physical models of capping systems. The research for this project employs primarily Baton Rouge area freshwater sediments inoculated with pyrene, phenanthrene, and dibenzofuran. Inoculated sediments are necessary to control contaminant fluxes within detectable ranges and generally provide a conservative estimate of cap containment in that contaminant mobility is likely enhanced by the required sediment processing. The inoculated compounds exhibited a range of hydrophobicities and mobilities (log octanol-water partition coefficients were 5, 4.5 and 4, respectively). Recognizing that differences in contaminant mobility are often noted between aged and freshly contaminated sediments, experiments were conducted with field contaminated sediments. Rouge River, Michigan sediments were acquired to evaluate these effects. The sediment contained significant levels of various PAHs including pyrene, and phenanthrene at levels similar to our inoculated sediments. The sediment also had oil and grease content of about 4% which could significantly effect the mobility of the contaminants.

Due to the slow time scale of migration through a cap, model development and validation was limited to experiments with sediments inoculated with toluene. This much less hydrophobic compound allowed migration rates that were sufficiently fast to allow experiments over a period of weeks to month to get measurable movement of the contaminant.

Cap Placement Technology
A bench scale laboratory facility with sediment surface area of 1.7 m2 was constructed to evaluate cap placement techniques and the mechanisms and rates of contaminant loss from the underlying sediments during placement. Cap placement was via near bottom placement, near-surface release and mechanically.

Long-Term Containment by a Cap
Containment losses by advective processes and localized cap failures were evaluated in bench scale laboratory experiments using the facility mentioned above. Laboratory experiments were used to develop criteria which identify significant losses from possible penetrations of the cap and to test and extend models of this process.

Publications and Presentations:

Publications have been submitted on this subproject: View all 16 publications for this subprojectView all 392 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 2 journal articles for this subprojectView all 106 journal articles for this center

Supplemental Keywords:

transport processes, contaminant modeling, and contaminant flux., RFA, Scientific Discipline, Geographic Area, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Chemical Engineering, Contaminated Sediments, Environmental Chemistry, Fate & Transport, Analytical Chemistry, Hazardous Waste, Ecology and Ecosystems, Hazardous, Environmental Engineering, EPA Region, region 4, fate and transport, environmental technology, sediment treatment, hazardous waste management, hazardous waste treatment, risk assessment, contaminated marine sediment, soil and groundwater remediation, sediment caps, biodegradation, contaminated sediment, PAH, chemical contaminants, contaminated soil, chemical kinetics, furans, marine sediments, remediation, biotransformation, control technologies, extraction of metals, technology transfer, leaching, contaminant transport models, heavy metals, bioremediation, CERCLA

Progress and Final Reports:

  • 1995
  • Final Report

  • Main Center Abstract and Reports:

    R825513    HSRC (1989) - South and Southwest HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825513C001 Sediment Resuspension and Contaminant Transport in an Estuary.
    R825513C002 Contaminant Transport Across Cohesive Sediment Interfaces.
    R825513C003 Mobilization and Fate of Inorganic Contaminant due to Resuspension of Cohesive Sediment.
    R825513C004 Source Identification, Transformation, and Transport Processes of N-, O- and S- Containing Organic Chemicals in Wetland and Upland Sediments.
    R825513C005 Mobility and Transport of Radium from Sediment and Waste Pits.
    R825513C006 Anaerobic Biodegradation of 2,4,6-Trinitrotoluene and Other Nitroaromatic Compounds by Clostridium Acetobutylicum.
    R825513C007 Investigation on the Fate and Biotransformation of Hexachlorobutadiene and Chlorobenzenes in a Sediment-Water Estuarine System
    R825513C008 An Investigation of Chemical Transport from Contaminated Sediments through Porous Containment Structures
    R825513C009 Evaluation of Placement and Effectiveness of Sediment Caps
    R825513C010 Coupled Biological and Physicochemical Bed-Sediment Processes
    R825513C011 Pollutant Fluxes to Aquatic Systems via Coupled Biological and Physicochemical Bed-Sediment Processes
    R825513C012 Controls on Metals Partitioning in Contaminated Sediments
    R825513C013 Phytoremediation of TNT Contaminated Soil and Groundwaters
    R825513C014 Sediment-Based Remediation of Hazardous Substances at a Contaminated Military Base
    R825513C015 Effect of Natural Dynamic Changes on Pollutant-Sediment Interaction
    R825513C016 Desorption of Nonpolar Organic Pollutants from Historically Contaminated Sediments and Dredged Materials
    R825513C017 Modeling Air Emissions of Organic Compounds from Contaminated Sediments and Dredged Materials title change in last year to "Long-term Release of Pollutants from Contaminated Sediment Dredged Material"
    R825513C018 Development of an Integrated Optic Interferometer for In-Situ Monitoring of Volatile Hydrocarbons
    R825513C019 Bioremediation of Contaminated Sediments and Dredged Material
    R825513C020 Bioremediation of Sediments Contaminated with Polyaromatic Hydrocarbons
    R825513C021 Role of Particles in Mobilizing Hazardous Chemicals in Urban Runoff
    R825513C022 Particle Transport and Deposit Morphology at the Sediment/Water Interface
    R825513C023 Uptake of Metal Ions from Aqueous Solutions by Sediments
    R825513C024 Bioavailability of Desorption Resistant Hydrocarbons in Sediment-Water Systems.
    R825513C025 Interactive Roles of Microbial and Spartina Populations in Mercury Methylation Processes in Bioremediation of Contaminated Sediments in Salt-Marsh Systems
    R825513C026 Evaluation of Physical-Chemical Methods for Rapid Assessment of the Bioavailability of Moderately Polar Compounds in Sediments
    R825513C027 Freshwater Bioturbators in Riverine Sediments as Enhancers of Contaminant Release
    R825513C028 Characterization of Laguna Madre Contaminated Sediments.
    R825513C029 The Role of Competitive Adsorption of Suspended Sediments in Determining Partitioning and Colloidal Stability.
    R825513C030 Remediation of TNT-Contaminated Soil by Cyanobacterial Mat.
    R825513C031 Experimental and Detailed Mathematical Modeling of Diffusion of Contaminants in Fluids
    R825513C033 Application of Biotechnology in Bioremediation of Contaminated Sediments
    R825513C034 Characterization of PAH's Degrading Bacteria in Coastal Sediments
    R825513C035 Dynamic Aspects of Metal Speciation in the Miami River Sediments in Relation to Particle Size Distribution of Chemical Heterogeneity