Grantee Research Project Results
Final Report: Development of Relevant Ecological Screening Criteria (RESC) for Petroleum Hydrocarbon-Contaminated Exploration and Production Sites
EPA Grant Number: R827015C011Subproject: this is subproject number 011 , 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: Center for the Study of Metals in the Environment
Center Director: Allen, Herbert E.
Title: Development of Relevant Ecological Screening Criteria (RESC) for Petroleum Hydrocarbon-Contaminated Exploration and Production Sites
Investigators: Lanno, Roman , Cross, Anne , Focht, Will
Institution: Oklahoma State University
EPA Project Officer: Aja, Hayley
Project Period: July 1, 2000 through June 30, 2001 (Extended to December 31, 2001)
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
Faced with the task of assessing cleanup options based on ecological risk-based criteria at thousands of small upstream sites, oil and gas producers are in need of a streamlined rationale for assessing ecotoxicological risk at these sites. The development of a risk based corrective action (RBCA) approach for the protection of ecological resources provides a mechanism for generic, as well as site-specific, approaches to ecological risk assessment (ASTM 2000). Within the RBCA framework, a provision exists whereby cleanup levels can be established on a site-specific basis, based upon sound scientific data for individual sites. This is appealing to the regulated community, since existing generic soil quality guidelines (SQGs) are extremely conservative in order to account for the heterogeneous nature of soil composition and chemical distribution.
The proposed study accepts the inevitability of the application of EU3CA-style decision- making in the remediation of petroleum-contaminated sites. However, it seeks to address two deficiencies of ecological risk-based decision making for petroleum-contaminated sites: 1) lack of a Relevant Ecological Screening Criterion (RESC) for petroleum- contaminated soils, and 2) reliance on the use of generic chemical criteria based on total, not bioavailable, chemical levels. The goal of our study was to develop a test data set for screening petroleum-contaminated sites that included the responses of an array of soil macroinvertebrates, plants, and microorganisms as effects assessment endpoints and measures of bioavailable petroleum hydrocarbon (BPH) and total petroleum hydrocarbon (TPH) as exposure measures. Together these measures would be used in the development of RESC for petroleum hydrocarbons in soil. Ideally, these RESC would be linked to an assessment endpoint of native tall grass prairie plant biodiversity and biomass, but this is unrealistic given the temporal and financial constraints of the funding period. The research was designed as a baseline study conducted in the laboratory using soils contaminated with crude oil in the field. The lack of a RESC for petroleum hydrocarbons in soils was addressed by conducting toxicity tests with field-contaminated soils using alternative test organisms (e.g., enchytraeids, Collembola, prairie plant species) as well as standard test organisms (e.g., earthworm, lettuce). Petroleum exposure was determined by measuring hydrocarbon exposure both as total petroleum hydrocarbon (TPH) and as bioavailable petroleum hydrocarbon (BPH) determined using solid-phase microextraction (SPME) fibers. Our thinking was that, although the results may appear to be limited in application to prairie ecosystems, by measuring bioavailable hydrocarbons and relating that to responses of a number of test species, it would be possible to transcend the restrictions of different soil types and apply these methods to assessing petrochemical contamination in different soils (e.g., hayfields, agricultural areas).
Specific objectives of the proposed research include:
1) Conduct soil toxicity tests with organisms for which no codified toxicity
tests are available (e.g., enchytraeids, collembola), as well as standard soil
test organisms (e.g., earthworms, plants), in field soils contaminated at different
levels with crude oil. The results of this objective will expand the database
available for conducting ecological risk assessments of contaminated soils.
2) Compare the toxicity of different levels of hydrocarbon in soil using both
total petroleum hydrocarbon (TPH) and bioavailable hydrocarbon (SPME extraction)
as measures of exposure.
3) Using the results of the previous two objectives, develop RESC for petrochemical-contaminated
sites on the Nature Conservancys Tallgrass Prairie Preserve (TPP), Pawhuska,
OK, for a number of relevant ecological receptors including soil invertebrates,
plants, and soil microbes. RESC will be estimated from no observed effect concentrations
("NOECs") or EC5 values for the test endpoints such as growth, reproduction,
or N-mineralization.
Summary/Accomplishments (Outputs/Outcomes):
TPH concentrations in contaminated soils ranged from 1,278 (ES1) to 13,250 (7Nl) mg/kg oil in soil. Bioavailable petroleum hydrocarbon levels (BPH) ranged from 83 µg hydrocarbon/kg soil in prairie reference soil to 3,620 µg/kg in sample 9N1. BPH measurements were highly variable, possibly due to the small soil mass (0.5 g) used in their determination. Earthworm survival was 100% in all contaminated and reference soils for the duration of the 28-day reproduction test. No significant difference in cocoon production was observed between earthworms in control (tilled prairie soil) or artificial soil and earthworms in all TPH-contaminated soils. However, a significant decrease in cocoon production with increased TPH concentration was observed when the reference soil (untilled prairie soil) was used in the regression analysis (p<0.001, R2 = 0.7844). Tests performed with Folsomia candida showed a significant reduction in juvenile production in all TPP treatments compared to the prairie reference soil, except for sample 6N1, where numbers of juveniles were similar. Due to low juvenile production, tests with Enchytraeus albidus did not meet validity criteria. No significant effect of treatment on the survival of Enchytraeus albidus was observed. Germination for lettuce (Lactuca sativa) and mustard (Brassica rapa) was >60% and >88%, respectively, but no treatment effect was observed. A significant increase in above ground biomass and stem height (day 14) was observed in mustard seedlings grown in soil ES1 compared to all other treatments. However, no treatment effect on mustard seedling stem height on day 28 or on lettuce seedling height was observed. Germination for Big Bluestem and Little Bluestem were both below 5% and germination of Maxmilian Sunflower was unsuccessful. Microbial analysis of soil samples collected over a two-year period at the sites contaminated by the crude oil spill in 1999 showed that numbers of aerobic heterotrophic bacteria varied little from site to site or seasonally and the number of naphthalene-degrading bacteria was generally considerably greater in the contaminated sites than in the uncontaminated sites, suggesting the microbial bioavailability of some hydrocarbons throughout the two-year period. Amplified bacterial PCR products separated by denaturing gradient gel electrophoresis (DGGE) were used to compare bacterial species diversity between sites and suggest decreased bacterial diversity in areas Contaminated by crude oil. No clear trend was evident in the amount of N-mineralized when comparing contaminated and uncontaminated sites. In total, 13 endpoints from seven different soil macroorganism tests and four microbial measurements were examined in this study. A generic RESC to be used in Tier 1 evaluations of diverse sites was not derived from these results because this study yielded only one toxic dose-response curve (earthworm cocoon production) despite the numerous species and toxicological endpoints tested. The TPH concentration corresponding to the EC50 derived from the earthworm reproduction data was 2118 mg/kg. In absence of any other data in this study, we recommend this soil TPH concentration as the Site Specific Ecological Criterion (SSEC) for the Tallgrass Prairie Preserve. An SSEC is a site-specific evaluation criterion based on an on-site risk assessment, rather than a generic RESC.
Conclusions:
- The ecological risk posed by the petroleum contamination at this site is minimal, despite the fact that some areas have greater than 13,000 mg TPH/kg soil. This level of contamination is higher than most effects levels reported in the literature. This reinforces the assertion that TPH is not a reliable measure of ecotoxicity. Furthermore TPH concentrations are not generalizable as thresholds for remedial action due to differences in crude oil composition and differential weathering patterns among chemical species within the crude.
- This study demonstrates that remediation efforts can quickly reduce soil toxicity to sub-lethal levels.
- Using native species for ecotoxicological assessments greatly improves ecological relevance of the tests. However, the difficulties of working with species about which little is known may make such tests impractical in many instances.
- Similarly, the use of native, in situ contaminated soils (field contaminated vs. laboratory spiked or amended) increases ecological relevance but can introduce significant limitations to the construction of dose response curves. A combined approach that uses both spiked and in situ contamination levels is recommended when using field soils.
- The development of a standard measure of bioavailability (e.g., bioavailable petroleum hydrocarbon, BPH) could circumvent the problems of working with native soils and native species by moving the measure of exposure (toxicity) from the environmental concentration to the potentially delivered dose. However, BPH levels were low throughout this study and did not assist in defining dose-response curves.
- This study confirmed earthworms, in particular the endpoint of cocoon production, as the most sensitive ecological receptor used to date in ecotoxicological assessments of petroleum-contaminated soils.
- Reduced performance of test organisms due to physical characteristics of the reference (prairie tilled) and control soil (artificial soil) were observed. Comparison of treatments to these soils requires careful qualification and interpretation, as results may suggest greater sensitivity of test organisms and produce overly conservative RESC values.
- Apparent hormetic effects were observed in tests with some organisms and methods need to be developed for the inclusion of such a response in the development of RESCS.
Journal Articles:
No journal articles submitted with this report: View all 5 publications for this subprojectSupplemental Keywords:
RFA, Scientific Discipline, Waste, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, RESEARCH, Bioavailability, Midwest, Contaminated Sediments, Remediation, State, Chemistry, Analytical Chemistry, Monitoring/Modeling, Monitoring, Bioremediation, Biology, Engineering, Environmental Engineering, petroleum, degradation, risk assessment, ecological screening, oil biodegradation, contaminated sediment, dose response, Tallgrass Prairie Perserve, Pawhuska, OK, microbes, chemical contaminants, soils, oil spills, toxicity, bioremediation of soils, soil, hydrocarbons, oil removal, environmental stressors, environmental toxicant, measurement, microorganism, sampling, refinery sites, Oklahoma (OK), toxicsProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R827015 Center for the Study of Metals in the Environment 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