Grantee Research Project Results
2000 Progress Report: Using Plants to Remediate Petroleum-Contaminated Soil
EPA Grant Number: R827015C007Subproject: this is subproject number 007 , 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
Investigators: Thoma, Greg , Beyrouty, Craig , Wolf, Duane
Institution: University of Arkansas
EPA Project Officer: Aja, Hayley
Project Period: September 1, 1999 through August 31, 2000 (Extended to June 30, 2001)
Project Period Covered by this Report: September 1, 1999 through August 31, 2000
Project Amount: Refer to main center abstract for funding details.
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
- To conduct greenhouse studies to screen plants for their ability to germinate and grow in weathered crude oil-contaminated soil with or without amendments.
- To survey and collect plant species currently growing on contaminated sites and screen the plants and rhizosphere microorganisms for their ability to enhance biodegradation of petroleum contaminants.
- To conduct an on-site field study to evaluate likely combinations of plants and management systems to enhance phytoremediation of weathered crude oil-contaminated sites.
- To develop a model that can be used to summarize and aid in the interpretation of experimental data collected in both the laboratory and field during the first experimental season.
Progress Summary:
This report covers the period through September 30, 2000 period and summarizes our current IPEC phytoremediation studies that consist of an on-site field project in southern Arkansas, greenhouse studies, and a mathematical modeling project.
Field Study
The field site in El Dorado, AR is located in a bermed area that is the site of an intentional spill by vandals approximately three years ago. The experimental plots consist of four replicates of the following treatments: (1) nonvegetated-nonfertilized control, (2) fescue-ryegrass-alfalfa + fertilizer, and (3) fescue-bermudagrass + 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. On 10-12 July 2000, 6 months after establishment of vegetation at the site, soil and plant samples were collected from the plots. Biological and chemical analyses of the soil sock samples are presented in Tables 1 and 2. The bacterial and fungal numbers were typical for levels of biological populations in crude oil-contaminated soil. There appeared to be an increase in microbial numbers in response to addition of fertilizer and vegetation with fescue + ryegrass having slightly larger populations than the bermudagrass plots (Table 1). Bacteria, fungi, and petroleum degrader numbers were higher in the vegetated, fertilized plots than in the no plant, no fertilizer control plots (Table 1). Addition of fertilizer and lime resulted in the expected increase in levels of plant available P, K, Ca, and Mg (Table 2).
All plant species appeared to be exhibiting adequate plant growth at the July sampling time. Plant samples were collected for shoot biomass (50 x 50 cm area over the soil sock), root biomass, root length, and root surface area. Bermudagrass sprigging in early spring 2000 was successful and the plants were growing well. Perennial cool season grasses were over-seeded and fertilized on 30 September 2000.
Table 1. Bacterial, fungal, and petroleum degrader numbers in crude oil-contaminated soil samples collected 12 July 2000 or 6 months after initiation of the field study in El Dorado, AR.
Treatment |
Bacteria |
Fungi |
Hexadecane |
Fuel Oil #2 |
|
log10 CFU/g dry soil |
log10 MPN/g dry soil |
||
Control No Fertilizer No Vegetation |
6.438 ± 0.080* |
5.107 ± 0.342* |
3.452 ± 0.220* |
3.144 ± 0.681* |
Fescue/Rye + Fertilizer |
7.191 ± 0.157 |
5.582 ± 0.249 |
4.353 ± 0.277 |
3.835 ± 0.939 |
Bermudagrass + Fertilizer |
6.987 ± 0.277 |
5.498 ± 0.445 |
4.073 ± 0.608 |
3.341 ± 0.280 |
All values are a mean of 4 samples ± 1 standard deviation except *, where values are a mean of 3 samples ± 1 standard deviation.
Table 2. Chemical properties of the crude oil contaminated-soil samples collected 12 July 2000 or 6 months after initiation of the field study in El Dorado, AR.
|
|
-------------Mehlich 3 Extractable------------ |
-----Total----- |
|||||
Treatment |
pH |
P |
K |
Ca |
Mg |
Na |
C |
N |
|
(1:1) |
mg/kg |
% |
|||||
Control No Fertilizer No Vegetation |
5.8 |
3.8 |
38.2 |
310.0 |
39.3 |
78.4 |
5.21 |
0.07 |
Fescue/Rye + Fertilizer |
6.0 |
19.2 |
94.3 |
426.5 |
75.6 |
83.6 |
4.74 |
0.08 |
Bermudagrass + Fertilizer |
5.9 |
23.1 |
113.7 |
419.6 |
76.5 |
63.7 |
5.00 |
0.08 |
*Values are the mean of four samples.
The Total Petroleum Hydrocarbon (TPH) and biomarker (hopane) analyses of the soil samples collected at the time of plot establishment (t=0) are presented in Table 3. Similar analyses for the t = 6 months soil samples are currently being conducted with the next soil sampling scheduled for December 2000.
Table 3. Total Petroleum Hydrocarbon (TPH) and biomarker (hopane) levels in the crude oil contaminated-soil samples collected 6 January 1999 at the initiation (t=0) of the field study in El Dorado, AR.
TPH Gravimetric |
TPH GC/FID |
TPH Criteria Working Group Method |
Biomarker Hopane |
|
Aliphatics |
Aromatics |
|||
--------------------------------------------mg/kg------------------------------------------- |
---µg/kg--- |
|||
25,250 ± 2,872* |
9,175 ± 866 |
2,925 ± 723 |
1,525 ± 386 |
1,700 ± 216 |
*Values are the mean ± standard deviation for four samples.
Greenhouse Study
Statistical analyses of the data have been completed for the experiment evaluating the survival and growth of alfalfa, bermudagrass, crabgrass, fescue, and ryegrass in weathered crude oil-contaminated soil amended with papermill sludge, broiler litter, inorganic fertilizer, or hardwood sawdust + inorganic fertilizer. Bermudagrass grown in crude oil-contaminated soil amended with broiler litter produced higher dry shoot biomass than any other plant amendment combination at 179 mg/plant. Ryegrass and crabgrass grown in broiler litter amended soil and crabgrass grown in soil amended with inorganic fertilizer also produced high yields, at 92, 91, and 113 mg/plant, respectively. Root biomass was determined and results showed that ryegrass grown in crude oil-contaminated soil amended with inorganic fertilizer or broiler litter produced significantly higher dry root biomass than alfalfa, bermudagrass, or crabgrass with any soil amendment at 108 and 101 mg/plant, respectively. Ryegrass grown in soil amended with sawdust + inorganic fertilizer, fescue grown in broiler litter amended soil, and crabgrass grown in inorganic fertilizer amended soil also produced high root biomass yields, at 90, 73, and 62 mg/plant, respectively.
Because oil-contaminated soils have different nutrient requirements than conventional agronomic recommendations suggest, a nutrient rate study using warm season plant species was conducted. The plants were recently harvested and data are currently being analyzed. Petroleum degrader populations in the rhizosphere and bulk soil were also determined to evaluate the influence of plant species and nutrient addition. Roots from all treatment combinations will be analyzed for length, radius, and surface area using the Win-Rhizo computer software.
Mathematical Model
Our initial model of phytoremediation consisted of two soil zones, the rhizosphere and the bulk soil. The current version of the model has been extended to include a root zone, six rhizosphere zones (concentric with the root structure and with individual degradation rate constants), a decaying root zone, and a bulk soil zone. The most recent extension of the model is the inclusion of the decaying root zone. This zone is thought to be significant in many situations. Literature models of root turn over have been evaluated and the incorporation of these models as forcing functions into the phytoremediation model is ongoing. A new graduate student has been added to the project, and he is familiarizing himself with the existing model and project in general.
New, time-dependent 3-D fractal models of the root structure have also been developed so that the variability of the rhizosphere volume through time as the roots grow and senesce can be included in the model. These root structural models must still be evaluated against the structure of real grass roots. As indicated above, we are currently using the WinRhizo system to collect this data for comparison. The images of these roots are similar to those in previous summaries, and are not included here.
Future Activities:
Evaluate numerical stability of the mathematical model solution of the 17 differential equations. Analyze field samples for biomass characteristics of shoot and root growth.
Journal Articles:
No journal articles submitted with this report: View all 3 publications for this subprojectSupplemental Keywords:
Arkansas (AR), petroleum, phytoremediation, EPA Region 6, rhizosphere., RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Water, Contaminated Sediments, Remediation, Chemistry, Environmental Microbiology, Microbiology, Hazardous Waste, Bioremediation, Molecular Biology/Genetics, Hazardous, Biology, Environmental Engineering, Engineering, petroleum, hazardous waste treatment, degradation, waste treatment, rhizospheric, petroleum contaminants, contaminated sites, microbial degradation, cleanup, biodegradation, decontamination of soil, petrochemical waste, microflora, microbes, soils, contaminated soil, bioremediation of soils, contaminants in soil, soil, models, hydrocarbons, phytoremediation, soil microbesProgress 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