Grantee Research Project Results

Bioturbation and Bioavailability of Residual, Desorption-Resistant Contaminants

EPA Grant Number: R828773C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R828773
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (2001) - South and Southwest HSRC
Center Director: Reible, Danny D.
Title: Bioturbation and Bioavailability of Residual, Desorption-Resistant Contaminants
Investigators: Reible, Danny D. , Pardue, J. , Fleeger, J. W.
Institution: Louisiana State University - Baton Rouge , Rice University
EPA Project Officer: Aja, Hayley
Project Period: October 1, 2001 through September 30, 2006 (Extended to September 30, 2007)
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (2001) Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The overall objective of the proposed research is to evaluate the dynamics of uptake and availability of desorption-resistant contaminants to tubificid oligochaetes and the corresponding consequences to control and regulation of contaminated sediments. Physicochemical measurements suggest that some contaminants are slow or limited in their release from the sorbed state. Evaluation of the influence of these physicochemical limitations to biological availability, however, has generally been limited to microbial degradation processes which often display an asymptotic approach to a persistent residual level. A much more intense biological challenge is presented by tubificid oligochaetes that often dominate disturbed, polluted environments and which feed and burrow in the sediments and which serve as food to higher organisms. Work to-date both in our laboratories and elsewhere has demonstrated that these organisms process sediments in large quantities, enhance contaminant release from bed sediments, and can absorb and metabolize polynuclear aromatic hydrocarbons (PAH) by digestive processes from ingested sediment. These organisms can access and assimilate desorption-resistant contaminants but the rate and extent is uncertain as is the relationship to physicochemical measurements. Preliminary measurements suggest that the rate of uptake is enhanced by the metabolic processes of tubificid oligochaetes but that the ultimate extent of uptake is determined solely by equilibrium factors. It is this hypothesis that will be tested in the proposed research.

Approach:

The focus will be on polynuclear aromatic hydrocarbons, nonpolar hydrophobic organic compounds that are important contaminants in the sediment environment and for which the most is known as to desorption-resistance. The dynamics of uptake and fate of desorption-resistant contaminants in tubificid oligochaetes will be measured and compared to the rates and extent of contaminant release by strictly physicochemical processes. Small microcosms that have been used extensively in our laboratories will be employed. The microcosms allow a complete contaminant material balance to be collected, including assessment of organism ingestion, uptake and egestion. Both cumulative measurements and single gut passage measurements will be used to indicate contaminant fate. In addition, fecal material will be evaluated by both physicochemical means and by microbial challenges to assess the influence of digestive processing on contaminant availability.

Expected Results:

The research is expected to relate physicochemical desorption resistance to biological availability in a class of organisms important to contaminated sediments. It is expected that the results will allow improved models of uptake to these organisms to be developed, ultimately improving the ability to predict food web uptake since these organisms reside at the base of benthic food webs. Ultimately, the research is expected to assist in answering questions as to required cleanup levels and the persistence of desorption resistant contaminants.

Publications and Presentations:

Publications have been submitted on this subproject: View all 36 publications for this subproject | View all 279 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 9 journal articles for this subproject | View all 63 journal articles for this center

Supplemental Keywords:

Bioturbation, sequestration, natural recovery., RFA, Scientific Discipline, Waste, Water, Contaminated Sediments, Environmental Chemistry, Microbiology, Environmental Microbiology, Hazardous Waste, Bioremediation, Hazardous, degradation, microbial degradation, bioavailability, biodegradation, contaminated sediment, turbificid oligochaetes, contaminated soil, PAH, contaminants in soil, bioremediation of soils, natural recovery, desorption-resistant contamination, biochemistry, phytoremediation, bioturbation

Progress and Final Reports:

Main Center Abstract and Reports:

R828773 HSRC (2001) - 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).
R828773C001 Bioturbation and Bioavailability of Residual, Desorption-Resistant Contaminants
R828773C002 In-Situ Containment and Treatment of Contaminated Sediments: Engineering Cap Integrity and Reactivity
R828773C003 Phytoremediation in Wetlands and CDFs
R828773C004 Contaminant Release During Removal and Resuspension
R828773C005 HSRC Technology Transfer, Training, and Outreach

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