SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM

SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
PHYTOREMEDIATION ACTION TEAM
TOTAL PETROLEUM HYDROCARBON IN SOIL SUBGROUP MEETING

Omni Austin Hotel Southpark
Austin, Texas
September 10, 2001

INTRODUCTION/STATEMENT OF GOALS

Steve Rock, one of the co-chairs of the Remediation Technologies Development Forum's (RTDF's) Phytoremediation Action Team, welcomed meeting attendees (see Attachment A) to the Total Petroleum Hydrocarbon (TPH) in Soil Subgroup meeting. He said that phytoremediation is "coming of age," noting that several consulting firms are using the technology and more than 80 universities are conducting phytoremediation projects. The TPH in Soil Subgroup has created a field study program to evaluate how effectively plants degrade petroleum hydrocarbons. During this meeting, Rock said, the program's progress would be discussed, and suggestions would be collected on how to improve data collection and analysis. Meeting participants opened the meeting by indicating what they hoped would be accomplished within the next five years:

Achieve more widespread use of the technology and use it to close Superfund sites.
Provide accurate estimates regarding how long it will take to achieve cleanup goals.
Obtain and disseminate data that will give potential users confidence that plant technologies work.
Prove that phytoremediation can be used to address recalcitrant compounds.
Prove that phytoremediation can be used across a wide variety of applications.
Prove that phytoremediation can be useful even in locations that have short growing seasons.
Show that phytoremediation can improve ecological conditions and create new habitat.
Identify and standardize analytical procedures for monitoring the success of phytoremediation.
Understand the chemical processes underlying phytoremedial mechanisms.
Use modeling tools to predict phytoremediation's performance and optimize the likelihood of success.
Develop guidance to help regulators determine whether plants are appropriate to use at a given site.⁽¹⁾
Obtain regulatory and community acceptance of the technology.

Lucinda Jackson advised reviewing this list at future meetings to determine whether progress has been made toward achieving these goals.

SECOND ANNUAL REPORT OF THE SUBGROUP'S COOPERATIVE FIELD TRIALS

Peter Kulakow, Kansas State University

Peter Kulakow provided background on the protocol, experimental design, sampling plan, and analytical methods that are being used under the Subgroup's field study program. He also presented a summary of the data that have been collected so far from five of the Subgroup's 13 sites. His presentation is included as Attachment B. The Subgroup's goal, Kulakow explained, is to show that contaminants degrade more quickly in vegetated plots than they do in unvegetated controls. Preliminary results suggest that this indeed may be the case at three of the five sites, though the results are not statistically significant at all of the sites. It is still too early, Kulakow said, to make any definitive conclusions about the results.

LABORATORY REPORT/INTERPRETATION OF ANALYTICAL DATA TO TRACK CHANGES AND ASSESS CONTAMINANT DEGRADABILITY

Henry Camp, Arthur D. Little Laboratory (ADL)

Henry Camp said that ADL plans to analyze about 500 to 600 samples under the Subgroup's field study program. (ADL is not the only laboratory performing analyses; a standard sample is being used to ensure that methods used across different laboratories yield comparable results.) Camp presented information about analytical challenges that have been encountered, presented data that have been collected from some of the Subgroup's sites, and discussed some of the different types of ratios that can be used to evaluate parameters. His presentation is included as Attachment C. His main points included the following: (1) degradation of TPH occurs slowly and subtly, (2) monitoring activities must be conducted over a long period, (3) contaminant variance is often a complicating factor, (4) chromatograms can be used to determine whether a contaminant mixture is becoming more or less toxic as it degrades, and (5) a number of different analytical methods can be used to assess phytoremediation's impact upon a site. Expanding upon the latter, Camp noted that evaluation designs may need to be site-specific to truly determine what is occurring at an individual site.

MATHEMATICAL MODELING OF PHYTOREMEDIATION

Greg Thoma, University of Arkansas

Greg Thoma presented information about a root growth model that is being developed at the University of Arkansas. Ideally, he said, the model will become a useful screening tool that will allow consultants to estimate how much time will be required for phytoremediation to reduce contaminant concentrations below cleanup standards. Thoma's presentation is included as Attachment D.

SITE SUMMARIES--TRIALS, TRIBULATIONS, TRIUMPHS, AND AMUSING MISHAPS

As noted above, the TPH in Soil Subgroup has created a field study program to evaluate how effectively plants degrade petroleum hydrocarbons. Meeting attendees provided updates on sites participating in the program. In addition, they also provided detailed information about lessons that have been learned.

Description/Update	Lessons Learned
Site A Site A is old; contaminants in the top soil layer were highly weathered before the phytoremediation project was initiated. Plants were established at Site A in December 1998. Growth has been robust; more biomass has been generated here than at any other Subgroup site. Roots have grown in shallow areas (0 to 6"), but have not penetrated significantly into deeper areas (6-12"). Time zero (T₀), time one (T₁), and time two (T₂) soil samples have all been collected and analyzed. The results fail to show that phytoremediation is exerting influence at the site. Time three (T₃) soil samples have been collected, but have not been analyzed yet. If the T₃ results prove to be more encouraging, the demonstration project may continue for another year. Plant tissue samples were also collected during the T₃ event. These will be assessed to determine whether hydrocarbon uptake has occurred. The final solution at Site A may involve covering the site with clean soil and installing a vegetation cap. If the T₃ plant tissue samples do not reveal significant hydrocarbon uptake, this will make it easier to obtain regulatory acceptance for the cap.	Managers should identify cleanup goals before project initiation. Foxes and burrowing animals (e.g., gophers) can confound sampling efforts. Roots may not be able to extend to deep layers if soil compaction cuts off oxygen diffusion or makes the ground too hard for roots to break through. Phytoremediation may not be overly effective against highly weathered materials. No significant contamination reduction has occurred in Site A's top soil. This is making site managers question whether phytoremediation will be effective in materials that are highly weathered. Positive results observed in the laboratory may be difficult to replicate in a field setting. More than three years of data may be needed to assess phytoremediation's efficacy.
Site B This site has three layers: a clay layer is at the bottom, glacial till lies on top of the clay, and refinery wastes are in the top layer. (The depth of the clay layer is not constant throughout the site; thus some samples have clay embedded in them, while others do not. This complicates the sampling process.) The site is surrounded by a wooded area; site managers hope to return the contaminated area to a forested environment. Phytoremediation is part of the closure plan.	Managers should identify the best planting schedule for each site. Trees were planted twice at Site B. Survival rates for the first planting event were low. This may have been because the trees were planted so late in the year. Pest control should be incorporated into management plans. Project managers should find out whether pesticides and herbicides can be used at a site. If not, creative pest control (e.g., BT) must be identified. Project managers should talk with regulators and stakeholders before initiating a project.
Sites C, D, and E: No update was provided for Sites C, D, or E.
Site F This site is a former manufactured gas plant (MGP). T_0, T₁, and T₂ soil samples have been collected. Results suggest that degradation rates differ across vegetated and unvegetated plots in a statistically significant fashion. T₃ samples will be collected in October 2001. The site owner might extend the project for four more years. The site is planted with seven different poplar/willow cultivars. The trees are planted on 1 foot centers. Site managers think they will thin out naturally. Some consideration is being given to copacing the trees.	It may be useful to till a site before establishing plants upon it. This will help make the soil less compacted.
Site G Contaminants at Site G are highly degradable. T₀ and T₁soil samples have been evaluated. The results indicate a statistically significant reduction in contaminant concentrations between vegetated and unvegetated plots.	Risk-based standards are effective tools. Site G is located in a state that uses risk-based cleanup standards. Contaminant concentrations have fallen below these standards after one year of phytoremediation activity.
Site H (see Attachment E) This site is contaminated with fuel oils, gasoline, kerosene, and diesel fuel. Vegetated plots have been established in the most contaminated portions of the site. In addition, the remainder of the site has been covered with the "RTDF mix" seeds. Sampling results are not yet available.
Site I (see Attachment E) A phytoremediation demonstration project has been established in a former fire training area. Site managers hope to convert Site I to a light industrial area with green spaces. Phytoremediation is being used to accomplish this goal. Sampling results are not yet available.	All site managers need to understand goals and procedures for site management. Communication breakdown occurred at this site. As a result, the site was accidentally tilled.
Site J Site J came into existence when an employee spilled 20,000 gallons of crude oil onto it. Some tilling was performed to homogenize the site. Even so, significant variation exists throughout the site. T_0, T₁, and T₂ soil samples have been collected, and preliminary results are available on the first two sample sets. The results suggest an encouraging trend. T₃ samples will be collected in March 2002. Microbial analyses are also being conducted.	Creative solutions must be used to address variability problems. The "buried bag" technique is being used to address variability at this site.
Site K This site is an MGP site. Plots have been established to evaluate phytoremediation, natural attenuation, bioslurry, and landfarming. An aquifer spring feeds the site. Thus, water-loving trees (i.e., poplars) have been used in the phytoremediation demonstration project. The trees, planted on 3-foot centers, were installed as 8-foot whips in May 1999. Drip irrigation was provided the first year, but was discontinued after that time. The trees are now 30 feet tall.	Site characterization should be extensive enough to allow investigators to obtain an understanding of a site's soil variability and set up appropriate site design. Toxicity and microbial analyses may help elucidate phytoremediation's impact. Soil samples at Site K have not provided meaningful results. Thus, investigators are using earthworm bioassays and most probable number (MPN) counts to assess phytoremediation. Cyanide may be present in buried fire brick. It would be useful to test for cyanide at MGP sites. (The contaminant may leach out and kill vegetation.)
Sites L and M Plants have not yet been established at these sites, but activities are scheduled to get underway very soon.

OPEN DISCUSSION

Rock mediated an open discussion session, and asked participants to comment on the following:

The Cost of Phytoremediation

Meeting attendees agreed that it is important to distribute information about how much phytoremediation technologies cost. Site owners will want to know two things:

How much does a pilot test cost?
How much will full-scale implementation cost?

Subgroup members hope to answer the first question. Toward this end, they are tracking the costs of their own demonstration projects. Steve Geiger questioned whether the costs calculated for the 13 Subgroup sites will really provide an accurate estimate. Site conditions vary dramatically, he noted; thus, the costs associated with each site may range greatly. Also, the site managers associated with each site may not be capturing their costs in a consistent manner. For example, while one site manager might include in-kind services in their startup costs, another might not. Geiger encouraged Subgroup members to be as consistent as possible. He also recommended including explanatory text to accompany the cost data; this text could explain how costs were calculated and summarize the main cost drivers for each site.

Kulakow said that most of the Subgroup members have already sent him information about costs incurred during the first year of the Subgroup field study program. In fact, this data, along with some text, is included in the most recent version of the annual report. Jackson suggested making some modifications to the text. As stated, she said, it implies that the cost per unit associated with the Subgroup's demonstration projects can be used as a proxy for that which would be incurred during a full-scale effort. She did not think this was accurate, noting that the cost per unit for demonstration projects will be disproportionately high; if someone were to conduct the project on a full-scale, she noted, they would not be expected to include as many replicates and to collect as many analytical samples. Other meeting attendees agreed with Jackson's point. Thus, they recommended making it clear that the cost per unit associated with demonstration projects does not correlate directly with the costs associated with full-scale projects.

Preliminary Conclusions--What Information Can Be Elucidated from the Field Trials?

Rock asked attendees to comment on the results that have been collected from the Subgroup demonstration sites thus far. He offered one observation: it appears that phytoremediation achieves results that are similar to those obtained through landfarming. Fiedler was not sure that Rock's preliminary conclusion could be supported. She noted that no biodegradation has been observed yet at some of the Subgroup sites (e.g., Site A). Kulakow said that firm conclusions cannot be made yet. At this point, too few data points have been collected.

How Should "Success" Be Measured?

Rock asked attendees to discuss methods that can be used to determine whether phytoremediation has been successful. For example, is it best to simply compare contaminant concentrations at the start and end of the project? If so, how much of a decrease is needed in order to label a project a "success"? Attendees suggested the following methods:

Compare final contaminant concentrations with cleanup standards. Geiger said that it would be useful to look up state cleanup standards for each of the sites that are included in the Subgroup field demonstration project. In addition, risk-based screening levels can be calculated using the TPH Criteria Working Group (TPHCWG) method.
Compare final contaminant concentrations with a "bioavailability" standard. Geiger provided a brief explanation of the bioavailability concept. There is growing evidence, he said, that some level of contamination can exist in the environment without harming ecological and human receptors. (See Assessing the Bioavailability of Organic Chemicals in Soil for Use in Human Health Risk Assessment at www.nepi.org.) Geiger said that sequestered contaminants are not bioavailable, and that a variety of factors, such as soil organic matter, nanoporosity, and wetting/drying cycles, impact sequestration rates. It would be interesting to find out, he said, whether phytoremediation accelerates sequestration rates by impacting these factors. Some scientists suggest that a site is "clean" if all bioavailable components have been removed and only non-biodegradable forms of a contaminant remain. At one site, where this approach was taken, remediation costs decreased by $2.5 to $4.0 million dollars because the cleanup level considered acceptable under the "bioavailability standard" was not as stringent as that specified under prescribed regulatory standards. (See: Stroo et al., 2000. Environmentally Acceptable Endpoints for PAHs at a Manufactured Gas Plant Site. ES&T 34 (18) 3831-3836.) Geiger asked whether attendees were interested in researching bioavailability at the Subgroup demonstration sites. They expressed strong enthusiasm. David Tsao knew of some Russian scientists who might be available to perform a study. Kulakow said that he has already written a proposal that asked for funds to perform bioavailability studies at the RTDF TPH in Soil Subgroup sites. Attendees agreed that Kulakow's text might serve as a good foundation for new proposals.

Before closing on the topic of "success," Fielder made an important point: phytoremediation's success should not be measured solely on its ability to reduce contaminants. Plants also provide significant additional benefits, such as erosion control and habitat restoration.

ACTION ITEMS

Subgroup members will review the annual report. Meeting attendees will submit comments to Kulakow by October 30, 2001. (Not all Subgroup members currently have a copy of the annual report. Kulakow agreed to send copies to Duane Wolf, Chris Nowak, Kathy Banks, Marcos Alvarez, and Phil Sayre. He will also call Evelyn Drake to find out how many copies she needs.) Attendees are specifically encouraged to comment on the following:
-- The most appropriate methods (e.g., measuring percent change of contaminant concentrations, analyzing chromatogram patterns, transforming data, evaluating biomarkers, or examining weathering ratios) for analyzing the Subgroup's data sets.

-- The portions of the text that address costs (i.e., Section 5.1, Table 5.1, and Table 5.2). Subgroup members should indicate whether cost categories are missing, and think about strategies that can be used to estimate full-scale costs.
Efforts will be made to update the RTDF Web site. Fiedler will collaborate with EMS to keep the RTDF Web site up-to-date. Fiedler noted that the annual report provides a list of useful phytoremediation references. She advised posting the reference list on the RTDF Web site, and adding links to existing reports. She asked attendees to review the list of references and to let Kulakow (kulakow@ksu.edu) or ERG (chartnet@erg.com) know if additional references should be added.

The Subgroup's Cooperative Research and Development Agreements (CRADAs) will be renewed if necessary. CRADAs have been established between EPA and site owners/managers participating in the Subgroup's field demonstration project. Some meeting attendees asked whether the CRADAs will expire before the Subgroup's work is complete. Rock will look up the expiration dates for all of the CRADAs. If they are due to expire, Rock said, the CRADAs can easily be renewed.
Subgroup members will review their 1st-year cost data. Kulakow said that most Subgroup members have already sent him information on the costs incurred during the first year of their demonstration projects. Geiger asked all Subgroup members to review the data they reported for initial startup costs, expressing concern that startup costs are underestimated at some sites. This would be the case, for example, if someone failed to list their own time or some other type of in-kind service as a cost.
Subgroup members will submit 2nd-year cost data. Kulakow asked Subgroup members to submit information on costs incurred during the second year of their phytoremediation demonstration projects. Tom Spriggs asked for a copy of the cost spreadsheet. Kulakow agreed to send it to him.
Subgroup members will determine whether resources are available for bioavailability studies. Kulakow agreed to send his "bioavailability proposal" to Rock and Tsao. This will be tweaked and then submitted to Argonne National Laboratories to determine whether Russian scientists are available to work on a bioavailability study.
Attendees will send Thoma feedback and data. Thoma said that his root growth model is still in development; thus, any suggested improvements would be greatly appreciated at this point. Rock asked Subgroup members to send Thoma the data that have been collected from Subgroup sites on root growth, density, and length.
ERG agreed to set up the next Subgroup conference call for October 30, 2001.

Attachment A: Attendee List
RTDF Phytoremediation of Organics
Total Petroleum Hydrocarbons (TPH) in Soil

Action Team Meeting

Omni Austin Hotel Southpark
Austin, Texas
September 10, 2001

Henry Camp
Principal
Arthur D. Little
25 Acorn Park
Cambridge, MA 02140
617-498-5339
Fax: 617-498-7296
E-mail: camp.henry@adlittle.com

Ross del Rosario
Remedial Project Manager
U.S. Environmental Protection Agency
77 West Jackson Boulevard (SR-6J)
Chicago, IL 60604
312-886-6195
Fax: 312-886-4071
E-mail: delrosario.rosauro@epa.gov

Richard Farrell
Research Scientist
Department of Soil Science
University of Saskatchawan
51 Campus Drive
Saskatoon, Saskatchawan
Canada
306-966-2772
Fax: 306-966-6881
farrell@sask.usask.ca

Linda Fiedler
Technology Innovation Office
U.S. Environmental Protection Agency
Ariel Rios Building (5102G)
1200 Pennsylvania Avenue
Washington, DC 20460
703-603-7194
Fax: 703-603-9135
E-mail: fiedler.linda@epa.gov

Steve Geiger
Senior Environmental Scientist
RETEC
2111 Wilson Boulevard - Suite 700
Arlington, VA 22201
703-351-5086
Fax: 703-351-9292
E-mail: sgeiger@thermoretec.com

Kate Grimberg
Environmental Engineer
Environmental Resources Management
17187 North Laurel Park Drive
Suite 235
Livonia, MI 48152
734-542-0740
Fax: 734-542-0734
E-mail: katherine_grimberg@erm.com

Victor Hauser
Principal Engineer
Center for Science and Technology
Mitretek Systems
13526 George Road - Suite 200
San Antonio, TX 78230
210-479-0479
E-mail: vhauser@mitretek.org

Lucinda Jackson
Senior Environmental Scientist
Chevron Corporation
100 Chevron Way
P.O. Box 1627
Richmond, VA 94802-0627
510-242-1047
Fax: 510-242-5577
E-mail: luaj@chevron.com

Joe King
District Manager
Camino Real Environmental Centers
P.O. Box 580
Sunland Park, NM 88063
505-589-9440
Fax: 505-589-2427
E-mail: halabu@aol.com

Peter Kulakow
Kansas State University
913-532-7239
Fax: 785-532-6094
E-mail: kulakow@ksu.edu

Timothy Looper
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-487-2860
E-mail: looper.timothy@epa.gov

Scott Potter
Principal Engineer
Arcadis Geraghty & Miller, Inc.
1131 Benfield Boulevard - Suite A
Millersville, MD 21108
410-987-0032
Fax: 410-987-4392
E-mail: spotter@arcadis-us.com

Steve Rock
Environmental Engineer
National Risk Management
Research Laboratory
U.S. Environmental Protection Agency
5995 Center Hill Avenue
Cincinnati, OH 45224
513-569-7149
Fax: 513-569-7879
E-mail: rock.steven@epamail.epa.gov

Tom Spriggs
Environmental Engineer
CH2M Hill
4350 West Cypress Street - Suite 600
Tampa, FL 33607
813-874-6522
Fax 873-874-3056

Greg Thoma
Associate Professor of Chemical Engineering
University of Arkansas
3202 BEC
Fayetteville, AR
501-575-7374
Fax: 501-575-7926
gthoma@uark.edu

Rick Tomlinson
Program Director
ITRC
444 N. Capitol Street
Washington, D.C. 20001
202-624-3669
Fax: 202-624-3666
RickT@sso.org

Rafael Vazquez
Environmental Engineer
Air Force Center for
Environmental Excellence
3207 North Road
Brooks AFB, TX 78235-5363
210-536-1431
Fax: 210-536-4330
E-mail: rafael.vazquez@hqafcee.brooks.af.mil

Paul White
Research Specialist
Department of Crop, Soil, & Environmental Science
University of Arkansas
Plant Science Building 115
Fayetteville, AR 72701
501-575-5739
Fax: 501-575-7465
E-mail: pmwhite@uark.edu

Logistical and Technical Support Provided by:

Christine Hartnett
Conference Manager/Technical Writer
Eastern Research Group, Inc.
5608 Parkcrest Drive - Suite 100
Austin, TX 78731-4947
512-407-1829
Fax: 512-419-0089
E-mail: chartnet@erg.com

Carolyn Perroni
Senior Project Manager
Environmental Management
Support, Inc.
8601 Georgia Avenue - Suite 500
Silver Spring, MD 20910
301-589-5318
Fax: 301-589-8487
E-mail: cperroni@emsus.com

Laurie Stamatatos
Conference Coordinator
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421
781-674-7320
Fax: 781-674-2906
E-mail: lstamata@erg.com

Attachments B through E

Attachment B: Second Annual Report of the RTDF TPH Subgroup Cooperative Field Trials

Attachment C: Laboratory Report/Interpretation of Analytical Data To Track Changes and Assess Contaminant Degradability

Attachment D: Mathematical Modeling of Phytoremediation

Attachment E: RTDF Site Updates: Site H and Site I

1. Progress has been made on this front. See Phytoremediation Decision Tree at http://www.itrcweb.org/phyto_1.pdf.