Final Report: Coupled Biological and Physicochemical Bed-Sediment Processes

EPA Grant Number: R825513C010
Subproject: this is subproject number 010 , 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: Coupled Biological and Physicochemical Bed-Sediment Processes
Investigators: Reible, Danny D. , Thibodeaux, Louis J. , Fleeger, J. W.
Institution: Louisiana State University - Baton Rouge
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 1992 through January 1, 1995
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


To evaluate the coupled effects of physicochemical and biological processes on contaminant transport from sediments. The focus was on bioturbation of oligochaete worms.

Summary/Accomplishments (Outputs/Outcomes):

Two sediment-dwelling tubificid oligochaete species (Tubifex tubifex and Limnodrilus hoffmeisteri) were chosen for study because they act as sediment destabilizing bioturbators (conveyor-belt feeders that ingest bulk quantities of sediment) by bringing sediment from depth, up to 3-4 cm, to the surface as a by-product of their feeding activities.

The organisms were placed in experimental microcosms and the flux from the sediment monitored as a function of time. The experimental chambers consist of a small plexiglass chambers, 15cm x 5 cm x 4.5 cm. The sediment (with or without bioturbators) is loaded into the chamber and water flowed over the top at rates of 500 ml/h. The effluent is collected at selected time intervals and the concentration of the contaminant determined using an HPLC. The flux of contaminant to the water thereby determined. The incurrent water is an artificial pond water (0.5 mN NaCl, 0.2mM NaHCO3, 0.05 mM KCl, 0.4 mM CaCl2). The sediment used is a native Louisiana sediment contaminated with polyaromatic hydrocarbons in the laboratory.

Worms were introduced into a contaminant-inoculated sediment in specially designed laboratory microcosms. The flux of contaminants to the water column by molecular diffusion (and other physicochemical transport processes) in control microcosms was contrasted with that due to sediment processing associated with tubificid-induced bioturbation. Organism density and oxygen effects on the flux of three hydrophobic model contaminants (viz pyrene, phenanthrene and dibenzofuran) from a local sediment (Bayou Manchac, LA) were investigated. Oxygen content influenced worm behavior; under oxic conditions worms burrowed deep within the sediment, whereas under hypoxic conditions worms spent more time a the sediment-water interface and defecated on the sediment surface. We concurrently measured defecation rates as an indication of worm activity and found that the lower levels of contamination used as tracers did not effect activity rates. However, defecation rates increased from 1-2 mg of sediment per day at the start to 3-4 mg per day on the 17th day of the experiment, indicating worm acclimation and growth. Contaminant flux increased by a factor of four in high-density treatments and by a smaller factor in low-density treatments relative to control sediments without organisms. Effective particle-based mass transfer coefficients associated with bioturbation by these organisms was of the order of 1 cm/yr. Hypoxia greatly increased the rate of flux due to increased mixing associated with surface defecation. In separate experiments designed to look at contrasting effect on sediment stability, a slightly decreased flux was observed in the presence of a sediment-stabilizing mucous.

Analysis revealed that the experimental biodifussion constant has a proportional square root dependency on the biomass density in the sediment (see Figure below). The figure below represents the measured biodiffussion constants obtained using the model plotted against biomass density. A number of different species is represented in this figure and includes both our results as well as some of the other more reliable measurements from other groups, most notably Matisoff (1982). It should be noted that our values agree well with other reported values, and that it shows an approximate square root dependency on the density. The organisms represent both marine and freshwater organisms. Given the variety of data sources, the effective biodiffusion coefficients correlate remarkably well with biomass density. Our data suggest that after 10 years flux from bioturbated sediment would be about 370 times greater than the flux from a non-bioturbated sediment if all other active processes are negligible.

Image 1

Summary of Results:

  • Developed an experimental apparatus capable of assessing contaminant flux induced by bioturbation
  • Measured bioturbation related mass transfer coefficients as a function of organism density
  • Developed defecation rate as an indicator of toxicity for tubificid oligochaete

  • Journal Articles on this Report : 2 Displayed | Download in RIS Format

    Other subproject views: All 13 publications 3 publications in selected types All 2 journal articles
    Other center views: All 392 publications 154 publications in selected types All 106 journal articles
    Type Citation Sub Project Document Sources
    Journal Article Lotufo GR, Fleeger JW. Toxicity of sediment-associated pyrene and phenanthrene to Limnodrilus hoffmeisteri (Oligochaeta: Tubificidae). Environmental Toxicology and Chemistry 1996;15(9):1508-1516. R825513C010 (Final)
    not available
    Journal Article Valsaraj KT, Thibodeaux LJ, Reible DD. A quasi-steady state pollutant flux methodology for determining sediment quality criteria. Environmental Toxicology and Chemistry 1997;16(3):391-396. R825513C010 (Final)
    R825513C017 (Final)
    not available

    Supplemental Keywords:

    bioturbation, contaminated sediments, and fate and transport., RFA, Scientific Discipline, 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, environmental technology, sediment treatment, hazardous waste management, hazardous waste treatment, risk assessment, fate and transport, contaminated marine sediment, soil and groundwater remediation, biodegradation, contaminated sediment, kinetics, chemical contaminants, contaminated soil, bioremediation of soils, oligochaete worms, marine sediments, remediation, chemical kinetics, hydrology, biotransformation, currents, anaerobic biotransformation, extraction of metals, bioturbation, technology transfer, heavy metals, bioremediation, aquifer fate and treatment, technical outreach

    Progress and Final Reports:

    Original Abstract
  • 1992
  • 1993

  • 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