SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
PHYTOREMEDIATION OF ORGANICS ACTION TEAM
TCE IN GROUND WATER SUBGROUP
CONFERENCE CALL

November 10, 1999
1:00 p.m.–2:30 p.m.

On November 10, 1999, the following members of the Remediation Technologies Development Forum’s (RTDF’s) Phytoremediation of Organics Action Team, Trichloroethylene (TCE) in Ground Water Subgroup, met in a conference call:

Linda Fiedler, Environmental Protection Agency (EPA), Technology Innovation Office (TIO)
Milton Gordon, University of Washington
Lee Newman, University of Washington
Keith Rose, EPA
Bob Tossell, GeoSyntec Consultants

Also present was Christine Hartnett of Eastern Research Group, Inc. (ERG).

INTRODUCTION

The TCE in Ground Water Subgroup has decided to refocus its mission statement, to broaden its goals, and to reassign Subgroup leaders. This process was initiated on October 13, 1999, when five Subgroup members met in a conference call. At the end of the call, Subgroup members agreed to hold another conference call in November 1999 to further define their goals and objectives. The proceedings from this second call are summarized below.

MISSION STATEMENT

Conference call participants opened the call by discussing the Subgroup’s mission statement. Working together, they agreed upon:

Conference call participants agreed that this statement is broad enough to encapsulate the Subgroup’s research interests. By using the words "development" and "application," Bob Tossell and Lee Newman noted, the mission statement implies that the Subgroup will pursue activities in the laboratory and in the field. Also, by listing three media of interest, the Subgroup is exhibiting its commitment to evaluating phytoremediation’s efficacy for several applications rather than just one medium. Although the conference call participants wanted to keep the mission statement broad, they did think it was necessary to keep the contaminants of concern narrowed down to some extent. For this reason, they decided to use the phrase "chlorinated solvents" rather than "chlorinated compounds." If the latter had been chosen, Tossell pointed out, projects involving polychlorinated biphenyls (PCBs) would have been included under the Subgroup’s mission statement. Newman said that such projects fall outside the Subgroup’s current scope. Tossell stressed that the mission statement is in draft form and that changes may still be recommended.

SUBGROUP LEADERSHIP—IDENTIFYING CO-CHAIRS AND A STEERING COMMITTEE

Linda Fiedler asked the conference call participants to discuss leadership, pointing out that each RTDF Action Team or Subgroup usually has two co-chairs. Conference call participants decided that the TCE in Ground Water Subgroup will have three co-chairs so that each sector participating in the Subgroup is represented:

• Government. Keith Rose, representing EPA, agreed to serve as a co-chair.

• Industry. Tossell, representing GeoSyntec Consultants, agreed to serve as a co-chair.

• Academia. Milton Gordon said that someone from the University of Washington will serve as a co-chair. He and Newman agreed to talk offline about who will take on this role.

In addition to assigning co-chairs, conference call participants talked about forming a Steering Committee. Tossell noted that the Bioremediation Consortium (another RTDF Action Team) took this tack and found it to be very beneficial. The Consortium’s Steering Committee consists of about seven industry representatives, all of whom are contributing money or in-kind services. Under their direction, training courses have been developed, field studies have been initiated, and papers have been written. Such accomplishments are impressive, Tossell said; the Consortium is an Action Team that should be emulated. Fiedler agreed that the Consortium’s leadership structure serves as a good model, but said that the TCE in Ground Water Subgroup’s Steering Committee will probably differ, at least initially, from that of the Consortium. For example, she said, Subgroup Steering Committee members will be asked to donate time rather than money.

Conference call participants agreed that a Subgroup Steering Committee of about seven to nine people should be formed. Tossell said that he has a list of people in the public and private sectors who might serve as suitable candidates. Newman said that she has also identified some industry representatives who might be interested in participating in the Subgroup’s activities. Tossell encouraged Newman and the other conference call participants to send him the names of potential Subgroup members. After receiving these, Tossell will create a master list and distribute it to Fiedler, Gordon, Newman, and Rose. During the next conference call, Newman said, participants can review the list and start determining who should be invited to participate in the Steering Committee.

Tossell agreed that a Steering Committee should be formed quickly, but suggested drafting a proposal before trying to attract Committee members. This proposal, he said, would provide a brief status report on the state of phytoremediation technologies, list the Subgroup’s mission statement, and identify the key questions that the Subgroup hopes to answer. Conference call participants thought this was an excellent idea, agreeing that the Subgroup’s core objectives should be established before expanding the group. The remainder of the call was then dedicated to defining goals, identifying research needs, and discussing potential Subgroup activities.

GOALS, RESEARCH NEEDS, AND POTENTIAL ACTIVITIES

Conference call participants held a lengthy brainstorming session, tossing out ideas for potential activities and areas of research that the Subgroup could pursue. Two major activities were recommended:

Develop a List of Questions and Design a Field Study Program to Answer Them

Fiedler said that the TPH in Soil Subgroup—another Subgroup within the RTDF Phytoremediation Action Team—has developed a field study program to evaluate phytoremediation’s efficacy in petroleum-contaminated sites. Several sites are participating in the program, she said, and are following a protocol that was drafted by the Subgroup. (Information on this Subgroup’s protocol can be found at http://www.rtdf.org/public/phyto/phytodoc.htm.) Using the TPH in Soil Subgroup as a model, Fiedler said, the TCE in Ground Water Subgroup could develop a field study program to evaluate phytoremediation at sites with chlorinated solvent contamination. If the Subgroup opts to do so, she noted, it will need to (1) identify a list of research questions, and (2) develop a study protocol that is designed to obtain answers to these questions. Conference call participants expressed interest in implementing a field study program and started identifying a list of research questions:

• How effective is phytoremediation? Conference call participants said that phytoremediation is a slow-acting technology. In fact, at some sites, Tossell said, the merits of a phytoremediation system may not be fully apparent for several years. This lag time is troubling to some site owners, Tossell said, because they fear that several years of time and money could be wasted only to find that a technology is not working. To combat this concern, additional information about this innovative technology’s efficacy needs to be generated. Tossell said that determining phytoremediation’s efficacy could be one of the Subgroup’s major goals.

• What role do plants and microbes play in the remedial process? Tossell noted that much work remains to be done before researchers gain a better understanding of the different roles that plants and microbial communities play in phytoremedial processes. Newman agreed with Tossell, noting that the roles may differ from site to site. For example, she said, researchers may find that plants are primarily responsible for chemical degradation at one site, but that the same processes are driven mostly by microbes at a different site.

• How are chemicals degraded and transported, and what is their eventual fate? Conference call participants agreed that little is known about the fate, transport, and degradation of contaminants in phytoremedial systems. Learning more about these processes will allow investigators to answer the following questions: (1) what happens to a solvent when it is in the plant? (2) does the contaminant enter the food chain? (3) is the contaminant converted into a gas and released to the atmosphere? Tossell strongly encouraged the Subgroup to focus their efforts on elucidating degradation pathways, noting that the University of Washington has already initiated some efforts in this area.

• What kind of monitoring needs to be performed? Newman noted that older technologies usually have well-defined monitoring requirements; this allows site owners to predict their monitoring costs with reasonable accuracy. For innovative technologies, like phytoremediation, monitoring requirements are not as well-defined and a regulator’s individual discretion plays a role in determining these requirements; thus, monitoring costs can vary significantly depending on who oversees the site. Some site owners, Newman said, are uncomfortable using phytoremediation because it is so difficult to anticipate monitoring requirements. She suggested that the Subgroup create monitoring requirement guidelines. If these are developed, she said, regulators can refer to them for recommendations and site owners can use them to get an idea of what is expected.

• What analytical methods should be used? Several groups are studying the efficacy of phytoremediation, Newman said, but there is little consistency in the type of analytical methods used. She recommended analyzing available methods to determine which are most effective and efficient. Using this information, she said, the Subgroup could issue a list of recommended methods. Such a list might be very useful to site owners; those who are interested in pursuing phytoremediation can predict remedial costs more accurately if they know what methods they can choose from.

• What protocols should be used for bench-scale studies, pilot studies, and full-scale implementation? Tossell said that it might be useful to develop standardized protocols for bench-scale studies, pilot studies, and full-scale implementation. Having these available, he explained, could be very useful to site managers.

Conference call participants said that they are very interested in implementing some field studies in an attempt to gain answers for the above-listed questions. They talked briefly about finding applicable sites to include in a field studies program. In the short term, Fiedler said, it might be useful to initiate studies at sites that already have phytoremedial systems. (Fiedler said that TIO has prepared a database that lists sites that are currently using phytoremediation to clean up chlorinated solvents.) In the future, however, the Subgroup should consider targeting new sites that have not yet initiated activities. At this point, conference call participants agreed, the Subgroup will focus on developing questions and protocols rather than identifying sites.

Create a Decision Tree

Little guidance is available, Newman said, to help site managers determine if their sites are good candidates for phytoremediation. Managers have expressed a need for modeling programs or pre-screening tools that will allow them to predict the likelihood of phytoremediation’s success. Newman asked Subgroup members if they were interested in developing a pre-screening tool. Conference call participants said that they were, and agreed that the tool should take the form of a decision tree. Tossell agreed to distribute a generic phytoremediation decision tree that he has already created, saying that this might serve as a starting point for the Subgroup to build upon. Fiedler said that the Interstate Technology Regulatory Cooperation Work Group may also be working on a phytoremediation decision tree.

Conference call participants agreed that the decision tree should be set up so that site managers can determine whether phytoremediation has a chance of success by simply plugging in site-specific parameters. Using such an approach will allow them to determine whether phytoremediation is technically feasible at their sites. Technical feasibility, however, is only one factor in determining whether a technology is chosen for a site. Cost also plays a significant role in the decision-making process, Rose stressed, noting that it would be useful to incorporate an economic component into the decision tree. Site managers could then use the tree to help them determine whether the technology is cost-effective compared to other technologies. The decision tree would be particularly useful, Rose said, if certain site-specific parameters could be linked to economic issues. For example, it would be helpful if the Subgroup could identify a threshold point for degradation rates and state that phytoremediation will be cost-competitive with other technologies if a site exhibits a degradation rate higher than the threshold point. Conference call participants thought that this was an interesting idea. Gordon cautioned, however, against setting up the decision tree so that it pits one technology against another in a direct comparison. In some cases, combining phytoremediation with another technology may be more cost-effective than using either technology on its own. Tossell thought this was an excellent point, noting that phytoremediation may break into the marketplace by being advertised as a secondary or tertiary treatment.

NEXT STEPS/ACTION ITEMS

• ERG agreed to set up the next conference call for November 24, 1999, between 1:00 p.m. and 2:30 p.m. (EST).

• Tossell encouraged conference call participants to analyze the mission statement and to feel free to recommend changes.

• Conference call participants agreed to send Tossell the names of people who might be good candidates for the Subgroup’s Steering Committee. Tossell said that he will compile these names into a list and distribute this to Subgroup members before the November 24, 1999, conference call.
  
  
• Fiedler, Gordon, Newman, Rose, and Tossell will review the list of research needs provided in this conference call summary report. During the November 24, 1999, conference call, these five Subgroup members will be asked to go over this list to determine if items should be added or deleted. Then, after distilling or expanding the list, Subgroup members will be asked to choose the issues that are most important to pursue. These issues will be combined with the Subgroup’s mission statement to create a proposal that describes the Subgroup’s future activities and goals.
  
  
• Tossell agreed to send a generic phytoremediation decision tree to the conference call participants.
  
  
• Conference call participants agreed to forward their mailing addresses, phone numbers, fax numbers, and e-mail addresses to ERG.