Final Report: Effect of Natural Dynamic Changes on Pollutant-Sediment InteractionEPA Grant Number: R825513C015
Subproject: this is subproject number 015 , 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: Effect of Natural Dynamic Changes on Pollutant-Sediment Interaction
Investigators: Tomson, Mason B. , Kan, Amy T.
Institution: Rice University
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
The overall objective of this research was to determine whether irreversible adsorption and desorption occur in natural sediments and dredge materials as a mechanism which needs to be considered in cleanup. When the idea was proposed there was considerable skepticism about the existence of such a process in real practical sediments and dredge materials. Therefore the first year was used for proof-of-concept and review purposes.
After considerable trial and error, modeling and testing with different sediments, solution conditions, separation protocols and hydrocarbon selection a base experiment was developed which demonstrated the feature of hysteresis that was proposed might exist (Fu, et al, 1994). Essentially, a base experiment consisted of adding a sediment to solution at about 1:10 (wt:vol) ratio and adding, e.g., C-14 labeled naphthalene to initiate adsorption. Then after a day the solution was poured off and desorption initiated by adding fresh solution without naphthalene. The desorption process was repeated many times.
During these experiments, adsorption was observed to conform to expected hydrophobic-based KOW/KOC ratios. The desorption path, however, was quite hysteretic, i.e. irreversible
Several compounds and conditions were tested and details of the desorption process were studied, including mass balance and extraction methodologies (Kan, et al., 1994). Many other factors were studied, such as adsorption and desorption time from minutes to months, several different compounds, varying OC content, and mass balance details. Numerous commonly used mechanisms of slow release, etc., were used to try to explain the observed hysteresis and none were found able to account for the reported experimental observations.
As a related issue, the general approach of calculating partitioning and solubility called "Universal Functional-Group Activity Coefficient (UNIFAC)" was obtained from John Prausnitz at Berkeley and tested. It was found that if a few corrections were made to the aromatic chlorine interaction terms that a much larger group of compounds of common interest to this research and general environmental work could be included. These corrections were made, coordinated with Prausnitz and published (Kan and Tomson, 1995). This work was co-sponsored by the Gas Research Institute division of Environmental Health and Safety as it relates to the fate of PCBs in gas pipelines.
In an attempt to elucidate the mechanism(s) of irreversible adsorption and desorption, M. Hunter developed a true surrogate model system as part of her Ph.D. thesis (1996). This system is composed of non-porous anatase (TiO2) particles coated with an anionic surfactant. It was found that the fraction of OC added to the anatase in the form of surfactant could be adjusted to within virtually any limits by multiple adsorption steps. Surprisingly, this adsorbed surfactant was not readily desorbed and the multiple layers would resist multiple desorption steps. This is suggestive of Langmuir-Blodgett multiple layer adsorption onto glass slides, etc.. These observations and discussion have been accepted for publication in Envi. Sci. and Tech. (Hunter, et al, 1996).
This model surrogate system was used to further investigate the process of irreversible adsorption and desorption. The majority of the work with this system was done either with 2,2',6,6'-tetrachlorobiphenyl (a PCB isomer) or with naphthalene. It was found that when the desorption process was continued via many more desorption steps that this constant level was much lower than predicted by normal partitioning theories. Desorption time was varied from minutes to months with no effect beyond an hour or two. A second aspect was investigated with this model system, that of capacity. Multiple adsorption steps with more PCB were done in a attempt to "swamp" or saturate the irreversible or low solubility compartment. Results of these several hundred experiments are contained in a paper submitted to Envi. Sci. and Technology (Kan, et al., 1996).
The nature of the irreversible, or low solubility, compartment was further studied using Lula sediment and naphthalene. With the Lula sediment it was found that there existed a well defined size of this irreversible compartment at about 10 g-Naph/g-sediment. This constant compartment size was found whether the adsorption was done in one, two, or several adsorption steps. After the irreversible compartment was "filled" additional adsorption of naphthalene was found to be completely reversible with a common adsorption and desorption isotherm, as expected from KOC relations. Also, during these studies, the fraction of the adsorbed naphthalene that ended in the irreversible compartment appeared to be about constant, at around 30-50% or the amount that was expected to adsorb. In any adsorption step the reversible portion could be modeled by a standard isotherm.
From all of these studies a reasonable consistent ad hoc model was proposed wherein adsorption takes place on the OC of the sediment and then a small portion of the OC rearranges to entrap a portion of the adsorbed hydrocarbon. This entrapped portion would be in a more stable thermodynamic environment and thereby desorb at a lower concentration. Even though this mechanism is reasonable, there is no evidence that it is correct nor of the key parameter that cause the effect. Also, the presently funded research group at Rice is doing testing with sediments samples that have been contaminated in the field for years and directly determining whether there exists a desorption compartment that has the properties observed in the laboratory.
Journal Articles on this Report : 6 Displayed | Download in RIS Format
|Other subproject views:||All 27 publications||7 publications in selected types||All 6 journal articles|
|Other center views:||All 392 publications||154 publications in selected types||All 106 journal articles|
||Fu GM, Kan AT, Tomson M. Adsorption and desorption hysteresis of PAHs in surface sediment. Environmental Toxicology and Chemistry 1994;13(10):1559-1567||
||Kan AT, Fu GM, Tomson MB. Adsorption/desorption hysteresis in organic pollutant and soil/sediment interaction. Environmental Science & Technology 1994;28(5):859-867.||
||Kan AT, Oddo JE, Tomson MB. Formation of two calcium diethylenetriaminepentakis (methylene phosphonic acid) precipitates and their physical chemical properties. Langmuir 1994;10:1450-1455.||
||Kan AT, Tomson MB. UNIFAC prediction of aqueous and nonaqueous solubilities of chemicals with environmental interest. Environmental Science & Technology 1996;30(4):1369-1376.||
||Kan AT, Hunter MA, Fu G, Tomson MB. Effectiveness of chemically enhanced solubilization of hydrocarbons. SPE Production & Facilities 1997;12(3):153-158.||
||Tomson MB, Kan AT, Oddo JE. Acid/base and metal complex solution chemistry of the polyphosphonate, DTPMP versus temperature and ionic strength. Langmuir 1994;10:1442-1449.||
Supplemental Keywords: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, modeling, chemical contaminants, contaminated soil, marine sediments, remediation, chemical kinetics, hydrology, pollutant - sediment interaction, currents, technology transfer, aquifer fate and treatment, technical outreach
Progress and Final Reports:Original Abstract
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