Grantee Research Project Results
2004 Progress Report: Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
EPA Grant Number: R827015C028Subproject: this is subproject number 028 , established and managed by the Center Director under grant R827015
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: IPEC University of Tulsa (TU)
Center Director: Sublette, Kerry L.
Title: Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
Investigators: Thoma, Greg , Wolf, Duane , Reynolds, Robert , Ziegler, Susan
Institution: University of Arkansas
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2003 through August 31, 2006
Project Period Covered by this Report: September 1, 2003 through August 31, 2004
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
Crude oil-contamination of soil often occurs in areas adjacent to wellheads and storage facilities. Phytoremediation is a promising tool that can be used to remediate such sites and uses plants and agronomic techniques to enhance biodegradation of the hydrocarbon compounds. The research objective of this study is to evaluate fertilizer addition and vegetation establishment on phytoremediation of crude oil-contaminated soil. Our current Integrated Petroleum Environmental Consortium (IPEC) phytoremediation studies consist of an onsite field project in southern Arkansas, a laboratory study on microbial ecology, and a mathematical modeling project.
Progress Summary:
Field Study
Materials and Methods. The field site in El Dorado, AR, is located in a bermed crude oil storage/separation facility that was the site of an intentional spill in 1997 by vandals. The experimental plots consist of four replicates of the following treatments: (1) nonvegetated-nonfertilized control; (2) ryegrass (Lolium multiflorum L.) - fescue (Festuca arundinacea Schreb.) + fertilizer; and (3) bermudagrass (Cynodon dactylon (L.) Pers.) - fescue + fertilizer. Each field plot has 12 microplots (> soil socks =) that contain homogenized soil that allow monitoring of the field treatments, on a smaller scale, with less effect of field variability of the contaminant levels.
Sampling of the field site at El Dorado, AR, occurred at 57 months after plot establishment. Data for soil nutrient levels and soil TPH levels are being processed. Analyses for microbial parameters and shoot biomass are complete, and statistical evaluation is underway.
Results and Discussion
For soil samples collected at 57 months, the microbial numbers show that bacterial and fungal numbers were greater in the vegetated-fertilized plots as compared to the control plots (Figure 1). There was no apparent difference between the fescue and Bermuda grass treatments for bacterial or fungal numbers, and numbers were within ranges expected for petroleum-contaminated soils. The number of petroleum-, PAH-, and alkane-degrader microorganisms suggested that levels were not different among the three treatments at the 57-month sampling (Figure 2). Numbers were consistent with previous observations for the plots. Shoot biomass was similar for Bermuda grass and fescue vegetation and indicated that substantial plant growth had occurred (Figure 3).
Figure 1. Bacterial and Fungal Numbers for Soil Samples Collected 57 Months After Plot Establishment at the El Dorado Field Site. The control treatment was not fertilized or vegetated. The fescue and Bermuda grass plots received fertilizer and lime to facilitate plant growth.
Figure 2. Petroleum-, PAH-, and Alkane-Degrader Microbial Numbers for the Three Treatments at the El Dorado Field Site for Samples Collected 57 Months After Plot Establishment
Figure 3. Shoot Biomass Production for the Three Treatments at the El Dorado Field Site for Samples Collected 57 Months After Plot Establishment
Mathematical Model
We have been investigating the behavior of a supporting model for calculation of the root and rhizosphere volume of fractal root systems. This supporting model will be used to help define the relationship between the fractional root volume and the rhizosphere. As the root density increases, there is greater overlap and interaction between the rhizosphere associated with adjacent roots. The current overall model does not completely account for this behavior. We have been testing the code on single segments to determine if the error in the calculation is dependent on the root segment orientation. As shown in Figure 4, over the range of angles allowed for the “slicing plane angle” there is very little correlation to the angle, except for angles approaching 90°. The average error for a computation with an ideal packing of volume elements of 5 per unit root radius is 0.001 percent with a range of -2.7 percent to 3.4 percent. The root mean square error is 0.33 percent (square root of the sum of squared errors). These simulations were performed for a single root segment with length 5 mm and radius of 1 mm. The starting endpoint was chosen from a uniform random distribution of coordinates, which fell inside the volume element centered on the origin. The direction vector was chosen by picking uniform random variates for the x, y, and z directions for the segment. Ten thousand segments were analyzed, and the error reported is the “voxel packing volume” compared to the analytically calculated volume for the segment. The minimum allowable angle is 37.5°.
Microbial
Figure 5 presents results of phospholipid fatty acid (PLFA) analysis from January 2003. There is little variation detected in bulk microbial community among the treatments. Overall, the soil community appears to be dominated by gram negative with some gram positive components, including actinomycetes. The planned 13C-tracer studies will allow us to decipher which components of this overall community are involved in the degradation of certain classes of hydrocarbons. We are continuing collection and analysis of the PLFA data.
Future Activities:
Our initial findings suggest that phytoremediation does reduce contaminant levels through the action of microbial communities associated with the rhizosphere. It is therefore important to develop successful agronomic management strategies that exploit this understanding. Our detailed knowledge, however, of the microbial ecology of the rhizosphere is lacking. We plan to use carbon-13 isotopic labeling of specific contaminants coupled with PLFA analysis to identify specifically which group of microbes are responsible for the degradation. We will continue to investigate the modes of action of a phytoremediation system, while keeping in mind that the ultimate goal of site cleanup remains.
Journal Articles:
No journal articles submitted with this report: View all 6 publications for this subprojectSupplemental Keywords:
rhizosphere, rhizodegradation, species selection, Arkansas, South Central United States,, RFA, Scientific Discipline, Waste, Water, Geographic Area, POLLUTANTS/TOXICS, Contaminated Sediments, Remediation, Chemicals, Chemistry, State, Environmental Microbiology, Hazardous Waste, Bioremediation, Hazardous, Environmental Engineering, degradation, waste treatment, petroleum, contaminated sites, microbial degradation, rhizospheric, petroleum contaminants, biodegradation, decontamination of soil, cleanup, Arkansas, microflora, microbes, soils, contaminated soil, microbial ecology, bioremediation of soils, contaminants in soil, soil, hydrocarbons, models, phytoremediation, soil microbesRelevant Websites:
http://www.rtdf.org Exit
http://ipec.utulsa.edu Exit
Progress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R827015 IPEC University of Tulsa (TU) Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827015C001 Evaluation of Road Base Material Derived from Tank Bottom Sludges
R827015C002 Passive Sampling Devices (PSDs) for Bioavailability Screening of Soils Containing Petrochemicals
R827015C003 Demonstration of a Subsurface Drainage System for the Remediation of Brine-Impacted Soil
R827015C004 Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C005 Microflora Involved in Phytoremediation of Polyaromatic Hydrocarbons
R827015C006 Microbial Treatment of Naturally Occurring Radioactive Material (NORM)
R827015C007 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C008 The Use of Nitrate for the Control of Sulfide Formation in Oklahoma Oil Fields
R827015C009 Surfactant-Enhanced Treatment of Oil-Contaminated Soils and Oil-Based Drill Cuttings
R827015C010 Novel Materials for Facile Separation of Petroleum Products from Aqueous Mixtures Via Magnetic Filtration
R827015C011 Development of Relevant Ecological Screening Criteria (RESC) for Petroleum Hydrocarbon-Contaminated Exploration and Production Sites
R827015C012 Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C013 New Process for Plugging Abandoned Wells
R827015C014 Enhancement of Microbial Sulfate Reduction for the Remediation of Hydrocarbon Contaminated Aquifers - A Laboratory and Field Scale Demonstration
R827015C015 Locating Oil-Water Interfaces in Process Vessels
R827015C016 Remediation of Brine Spills with Hay
R827015C017 Continuation of an Investigation into the Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C018 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C019 Biodegradation of Petroleum Hydrocarbons in Salt-Impacted Soil by Native Halophiles or Halotolerants and Strategies for Enhanced Degradation
R827015C020 Anaerobic Intrinsic Bioremediation of MTBE
R827015C021 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R827015C022 A Continuation: Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C023 Data for Design of Vapor Recovery Units for Crude Oil Stock Tank Emissions
R827015C024 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells
R827015C025 A Continuation of Remediation of Brine Spills with Hay
R827015C026 Identifying the Signature of the Natural Attenuation of MTBE in Goundwater Using Molecular Methods and "Bug Traps"
R827015C027 Identifying the Signature of Natural Attenuation in the Microbial
Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and
"Bug Traps"
R827015C028 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R827015C030 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R827015C031 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R827015C032 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633 Integrated Petroleum Environmental Consortium (IPEC)
R830633C001 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells (Phase II)
R830633C002 A Continuation of Remediation of Brine Spills with Hay
R830633C003 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R830633C004 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R830633C005 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633C006 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R830633C007 Identifying the Signature of the Natural Attenuation in the Microbial Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and “Bug Traps”
R830633C008 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R830633C009 Use of Earthworms to Accelerate the Restoration of Oil and Brine Impacted Sites
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
Main Center: R827015
120 publications for this center
16 journal articles for this center