Final Report: Bioavailability, Complex Mixtures, and In-Situ Bioremediation of Organic Contaminants

EPA Grant Number: R825415
Title: Bioavailability, Complex Mixtures, and In-Situ Bioremediation of Organic Contaminants
Investigators: Brusseau, Mark , Miller-Maier, Raina M.
Institution: University of Arizona
EPA Project Officer: Lasat, Mitch
Project Period: November 1, 1996 through October 31, 1999
Project Amount: $487,377
RFA: DOE/EPA/NSF/ONR Joint Program on Bioremediation (1996) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The overall goal of this project was to enhance the understanding of the impact of bioavailability and related factors on the biodegradation and in situ bioremediation of organic contaminants in subsurface systems. The specific objectives that have been addressed include: (1) develop methods for in situ measurement of microbial activity in soil; (2) investigate the effects of residence time, cell transport, and microbial lag on bioavailability and biodegradation of organic compounds; (3) investigate the influence of bacterial population heterogeneity on bioavailability of organic compounds; (4) evaluate the use of biosurfactants for enhancing bioavailability and biodegradation of organic compounds; and (5) develop and evaluate mathematical models capable of simulating biodegradation and transport in complex systems.

Summary/Accomplishments (Outputs/Outcomes):

In Situ Measurement of Microbial Activity in Soil

Local Scale?Two methods have been developed that allow in situ measurements of microbial activities/distribution in soil systems at the local (e.g., column) scale (Objective 1). The first method involves a luminescence detection system that couples a genetically engineered bioluminescent report organism and fiber optic technology that can be used to monitor microbial activity under dynamic conditions. The second method involves an agar lift-DNA/DNA hybridization technique for use in visualizing the spatial distribution of bacteria on soil surfaces. These methods have been used to correlate microbial activity with the magnitude and rate of biodegradation measured during miscible-displacement transport experiments. For example, these methods were used to investigate the impact of substrate residence time and initial concentration, microbial lag, and population growth on the bioavailability and biodegradation of model hydrocarbons (Objective 2). These methods should prove useful for characterizing the coupled nature of biodegradation, microbial dynamics, and solute transport.

Field Scale?Evaluating the feasibility of using intrinsic or accelerated in situ bioremediation for a specific site requires a determination of the in situ biodegradation potential of the target contaminants in the contaminated zone. Additionally, the design and performance-evaluation of in situ bioremediation programs requires quantitative information concerning the magnitude and rate of expected and actual biodegradation. As has been widely discussed, it is often difficult to accurately determine the potential for biodegradation and bioremediation of a specific contaminant at a specific field site. It is even more difficult to quantify the magnitude and rate of biodegradation of the contaminant. Existing methods for characterizing biodegradation potential include laboratory experiments using soil samples collected from the field and field monitoring of temporal and spatial changes in concentrations of parameters associated with biodegradation, such as CO2, O2, intermediary metabolites, and the substrate (contaminant) itself. Both of these approaches have associated constraints that limit their robustness. In addition, the initial mass of contaminant released into the subsurface is not known at most sites. Thus, it is not possible to conduct a mass balance, which makes it difficult to quantify the magnitude and rate of biodegradation. An alternative approach for characterizing biodegradation potential involves the use of biogeochemically reactive tracers (biotracers), such as electron acceptors or surrogate organic compounds. A biotracer method has been developed based on the use of surrogate organic compounds. The biotracer test can be used to: (1) evaluate the general biodegradation potential associated with the zone of interest; (2) evaluate the biodegradation potential for a specific contaminant; and (3) evaluate the response of the system to perturbations. This method has been tested at two field sites, and results have been obtained that suggest the method can be used successfully to characterize the in situ biodegradation potential of a contaminated site.

Additional Activities

In addition to the extensive work discussed above, several other aspects related to bioavailability and biodegradation of organic compounds in soil systems have been examined. For example, the influence of immiscible organic liquid phases on the bioavailability and biodegradation of model polyaromatic hydrocarbons, and the impact of biosurfactant addition have been examined. In addition, mathematical models designed to simulate biodegradation and transport of contaminants in complex systems have been developed and tested. For example, the capabilities to simulate microbial growth and decay; lag effects; nonlinear, rate-limited sorption/desorption; and biodegradation activity of multiple microbial species have been implemented.

A recent focus of this research has been the behavior of microbial communities that contain multiple populations capable of degrading the target substrate. In an initial set of column experiments using phenanthrene and an unamended field sole, unique and complex biodegradation and transport behavior for phenanthrene was observed. Analysis of effluent and soil samples using ERIC and 16S-rDNA PCR methods indicated that 24 species capable of degrading phenanthrene were present in the soil system. The results of initial analyses suggest that the heterogeneous population experienced succession, inter-species competition, and perhaps gene-transfer during the 6-month experiment. These results will serve as the basis for future proposed research.


Journal Articles on this Report : 6 Displayed | Download in RIS Format

Other project views: All 17 publications 6 publications in selected types All 6 journal articles
Type Citation Project Document Sources
Journal Article Brusseau ML, Xie LH, Li L. Biodegradation during contaminant transport in porous media: 1. Mathematical analysis of controlling factors. Journal of Contaminant Hydrology 1999;37(3-4):269-293. R825415 (1999)
R825415 (Final)
not available
Journal Article Jordan FL, Maier RM. Development of an agar lift-DNA/DNA hybridization technique for use in visualization of the spatial distribution of eubacteria on soil surfaces. Journal of Microbiological Methods 1999;38(1-2):107-117. R825415 (1999)
R825415 (Final)
not available
Journal Article Li L, Yolcubal I, Sandrin S, Hu MQ, Brusseau ML. Biodegradation during contaminant transport in porous media: 3. Apparent condition-dependency of growth-related coefficients. Journal of Contaminant Hydrology 2001;50(3-4):209-223. R825415 (Final)
not available
Journal Article Sandrin SK, Jordan FL, Maier RM, Brusseau ML. Biodegradation during contaminant transport in porous media: 4. Impact of microbial lag and bacterial cell growth. Journal of Contaminant Hydrology 2001;50(3-4):225-242. R825415 (Final)
not available
Journal Article Sandrin SK, Brusseau ML, Piatt JJ, Blanford WJ, Nelson NT, Bodour AA. Spatial variablity of in situ microbial activity: Biotracer tests. Ground Water 2004;42(3):374-383. R825415 (Final)
not available
Journal Article Yolcubal I, Pierce SA, Maier RM, Brusseau ML. Biodegradation during contaminant transport in porous media: V. The influence of growth and cell elution on microbial distribution. Journal of Environmental Quality 2002;31(6):1824-1830. R825415 (Final)
not available

Supplemental Keywords:

groundwater, soil, biodegradation, bioavailability, chemical transport, risk assessment, chemicals, solvents, NAPL, remediation, cleanup, hydrology, measurement methods,, RFA, Scientific Discipline, Toxics, Geographic Area, Waste, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Ecology, Remediation, Environmental Chemistry, Chemistry, HAPS, State, chemical mixtures, Bioremediation, Biology, Engineering, complex mixtures, fate and transport, microbiology, hydrocarbon, biodegradation, Hill Air Force Base, adsorption, chemical transport, subsurface systems, mass transfer, sorption contact time, hazardous waste cleanup, in situ bioremediation, Arizona (AZ), chemical releases, biosurfactant specifity, vadose zone, bacterial degradation, groundwater

Progress and Final Reports:

Original Abstract
  • 1997
  • 1998 Progress Report