Final Report: Mobilization and Fate of Inorganic Contaminant due to Resuspension of Cohesive Sediment.

EPA Grant Number: R825513C003
Subproject: this is subproject number 003 , 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: Mobilization and Fate of Inorganic Contaminant due to Resuspension of Cohesive Sediment.
Investigators: Amirtharajah, A. , Tiller, C. L. , Sturm, T. W.
Institution: Georgia Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 1995 through January 1, 1998
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


This research was done to improve current methodology for prediction of contaminant movement as a result of episodic storm events in order to better assess risks to aquatic life and human exposure and to recommend appropriate remedial action. The following specific objectives were proposed:

  1. Generalize cohesive-sediment erosion relationship developed in earlier funded research in both flume and column studies using contaminated field sediments from the S&SW Region.
  2. Evaluate the release of contaminants associated with sediments due to changes in water chemistry under simulated dredging operations.
  3. Evaluate the mobilization of heavy-metal contaminants associated with resuspended sediments and the potential for enhanced release of the heavy metals into the aqueous phase.
  4. Incorporate the erosion relationship and the contaminant mobilization/release information into a numerical model of transport of sediments contaminated by heavy metals and the release of these metals into solution.
  5. Assess the contribution of storm-related episodic events on sediment transport and heavy metal mobilization in the field.
  6. Apply numerical algorithms of sediment resuspension and contaminant mobilization in a field study and compare numerical results with field data.

Summary/Accomplishments (Outputs/Outcomes):

The contaminant studies can be divided into 3 different subtasks; 1) batch studies, 2) column and flume studies, and 3) field studies. The subtasks are described below.

Batch Studies
The immobilization and release of copper, cadmium, and barium were studied in batch reactor systems. These investigations covered a range of sediment types, from laboratory-produced clay suspensions that have varying organic matter content to sediment samples acquired from uncontaminated field sites to sediment samples acquired from contaminated field sites.

For the uncontaminated natural sediment samples, well-mixed batch reactor experiments were conducted to determine the equilibrium extent of adsorption of copper, cadmium, and barium as a function of pH, ionic strength, DOC, and calcium concentration. In addition, similar experiments were conducted using laboratory-produced suspensions of kaolinite clay that was pre-coated with varying amounts of soil humics from the Suwanee river. Effects of varying solution chemistry on the release of metals from contaminated sediments were investigated in parallel fashion. One of the applications of these results was to provide baseline information for the development of models of contaminant release during sediment resuspension in the flume experiments and in the field.

Column and Flume Studies
Column studies with contaminated clays were conducted to determine the release of contaminants under fluidized conditions. Sediments from a field site (Etowah River sediments) were used for experiments with downflow filtration attachment on glass beads followed by detachment at varying upflow conditions under fixed and fluidized beds. In addition to the mass of particles detached, measurements were made of the contaminants released such as the heavy metals. The experimental protocol for the experiments were well established during earlier work. The emphasis in this study was to measure the contaminants released with colloidal-sized particles. The experiments were completed at the ionic strength and pH conditions which are typically experienced in the field. The second series of column experiments used the sediment itself in a fixed-bed configuration and determined the release of particles and contaminants at varying flow conditions.

The flume studies were conducted in the recirculating mode with both contaminated and uncontaminated sediments. The resuspension of the sediment was measured under time-varying conditions for the heavy metals in both the dissolved and adsorbed phases. The results obtained in the column and flume experiments were related to the batch studies on the rate and extent of desorption of the contaminants.

Field Studies
Field studies were done to test the sediment resuspension and barium mobilization models developed in the batch and flume studies. An existing numerical model was modified with respect to the sediment resuspension function and barium mobilization relationships as applied to the field data. The resuspension relationship developed in the flume studies of the actual field sediment and the adsorption relationship determined in the batch studies were used in the numerical model.

Rheology studies indicate that measurements of yield stress show some promise for predicting sediment bed stability. However, the time scale of the measurements is very important, and the results tend to be measures of the bulk rheologic properties of the sediment sample. Nevertheless, yield stress measurements showed similarity to critical shear stress measurements in the flume as the pH of the sediment suspension was changed.

Numerical modeling of a highly unsteady river flow due to hydropower pulses was successfully applied to field data from the Etowah River. A fine sediment transport model was developed with emphasis on the source term of the advection-diffusion equation. The resuspension portion of the source term was based on flume studies of erosion of the river sediment. A numerical stability analysis was performed to improve the numerical model. The numerical predictions of unsteady sediment concentration due to resuspension by the hydropower wave compared well with measured data.

The batch studies have provided specific information on sorption and release behavior of copper on kaolinite and release of barium from the Etowah River sediment. The results show that water chemistry parameters such as pH, ionic strength and organic matter play a major role in the surface chemistry of particulate matter and the sorption/retention of trace metals on the particulate matter.

The results of the research have further demonstrated the significant impact that types of particle-particle interactions in cohesive sediments can have on their rates of erosion. Theoretical calculations of interparticle forces have successfully predicted the types of particle interactions to be expected under given conditions of pH and organic matter and hence can be used to explain the experimental erosion and detachment behavior observed in cohesive sediments. Of even more significance for future research is that the microscopic force calculations provide a theoretical basis for predication critical shear stresses and hence ultimately, erosion relationships.

Summary of Results:

  • Established quantitative relationship for interaction between colloidal particles in sediment beds, confirmed in flume and column tests
  • Determined that principal parameters are hydrophobic and hydration forces at the microscopic level, advancing traditional DLVO Model for particle-particle stability
  • Established behavior and kaolinite behavior in stream and modeled contaminant transport

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 12 publications 4 publications in selected types All 3 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 Dennett KE, Sturm TW, Amirtharajah A, Mahmood T. Effects of adsorbed natural organic matter on the erosion of kaolinite sediments. Water Environment Research 1998;70(3):268-275. R825513C003 (Final)
  • Abstract: Ingenta-Abstract
  • Journal Article Mahmood T, Amirtharajah A, Sturm TW, Dennett KE. A micromechanics approach for attachment and detachment of asymmetric colloidal particles. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2001;177(2-3):99-110. R825513C003 (Final)
  • Full-text: PSU-Full Text PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Ravisangar V, Dennett KE, Sturm TW, Amirtharajah A. Effect of sediment pH on resuspension of kaolinite sediments. Journal of Environmental Engineering 2001;127(6):531-538. R825513C003 (Final)
  • Abstract: ASCE-Abstract
  • Supplemental Keywords:

    interparticle forces, dredging, and storm events., 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, sediment resuspension, chemical contaminants, contaminated soil, bioremediation of soils, marine sediments, remediation, chemical kinetics, hydrology, biotransformation, flume studies, currents, anaerobic biotransformation, extraction of metals, technology transfer, heavy metals, bioremediation, aquifer fate and treatment, technical outreach

    Progress and Final Reports:

    Original Abstract
  • 1995
  • 1996

  • 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