SUMMARY OF THE REMEDIATION TECHNOLOGIESDEVELOPMENT FORUM
PHYTOREMEDIATION OF ORGANICS ACTION TEAM
VEGETATIVE CAP SUBGROUP
CONFERENCE CALL

                   June 26, 1997
                      11:00 a.m. to 12:30 p.m.

On June 26, 1997, members of the Phytoremediation of Organics Action Team, Vegetative Cap Subgroup, met in a conference call. The following members were present:

Tom Wong, Union Carbide Corporation (Subgroup Co-chair)
Steven Rock, EPA/NRMRL (Subgroup Co-chair)
Victoria Van Cappellen, NewFields, Inc.
Lucinda Jackson, Chevron
Phil Sayre, EPA/TIO
Bruce Pivetz, ManTech Environmental Research Services Corporation
Christina Negri, Argonne National Laboratory

Also present was Ben Carlisle of Eastern Research Group, Inc. (ERG).

ADMINISTRATIVE ISSUES

Subgroup leader Tom Wong opened the conference call by asking participants if they approve of the idea of posting conference call minutes on the Remediation Technologies Development Forum (RTDF) homepage. The participants agreed that minutes should be posted. Several Subgroup members stated that they had experienced difficulties accessing the RTDF homepage (www.rtdf.org), which is temporarily out-of-order. The homepage can currently be reached at an alternative address: http://clu-in.com/rtdf/rtdf.htm.

Wong requested that ERG e-mail copies of conference call minutes to all participants and to people on the Vegetative Cap Subgroup mailing list. Wong also asked that ERG send out early confirmation of each upcoming conference call.

REVIEW OF MAY 30 CONFERENCE CALL

Wong quickly read through the minutes of the May 30 conference call. The Subgroup then went on to discuss several items listed in the minutes under "Proposed Action."

Finding Appropriate Sites

Steve Rock said he had heard from Greg Harvey of the U.S. Air Force that there are "a thousand Air Force sites that have TCE contamination at appropriate depths." Rock said he had also heard that there are hundreds of sites in the western U.S. that would be appropriate for vegetative caps.

Rock said that EPA Region 9 received a proposal from the Desert Research Institute (Pacific Northwest Laboratory) to do a study on vegetative covers. Rock is working with personnel from the Institute to merge their proposal with an EPA proposal of his own, and together they have begun looking for a "good" study and a number of appropriate sites. The Institute has done a lot of research, Rock said, and several states (California, Nevada, Utah, New Mexico, and Arizona) have already agreed to waive their regulations to allow such a study to occur, though none so far have committed funding. The Institute has several sites in mind, and the Air Force may have other sites. Rock's EPA proposal lists 20 potential sites west of the Mississippi, most of which are municipal waste sites.

Rock also said that he has discovered a tree planter in Iowa--Lou Licht, of Ecolotree--who has installed vegetative cap systems at eight sites, ranging from Oregon to Baltimore to Slovenia. The caps cover lined landfills, and Ecolotree is monitoring the systems to see how much leachate they collect. Rock said that Licht is more interested in remediative caps that capture leachate rather than in water-balance cover.

Bruce Pivetz noted that there are quite a few proposed sites in the western U.S. Pivetz asked about sites in the more humid east and southeast, and whether the Subgroup is interested in validating caps in all climactic conditions. Rock said that he's interested in seeing vegetative caps everywhere, though they may be an easier sell in regions where there's less rainfall. Vegetative caps will work in areas that receive 15" or less rainfall per year, though some people feel that 36" of rain per year may be beyond what a vegetative cap can control. Wong pointed out a topic for possible research: Is a vegetative cap suitable in all climates?

Christina Negri spoke about an Argonne study that may produce data indirectly related to Wong's question. EPA has asked a forest preserve near Chicago to remove all the trees growing over an existing landfill, Negri said; EPA apparently fears that the trees' roots may puncture the landfill's clay cap, creating problems with the leachate. The preserve would prefer not to remove the trees (for landscaping and recreational reasons), and thus asked Argonne to study what's happening with the root systems. Argonne is currently surveying the trees and vegetation at the site. The company will be removing some roots to determine whether they have punctured the clay cap, and will also check water balance to see if the vegetation is taking up too much water (thus reducing leachate production).

Wong spoke about Union Carbide's site in Texas City--a one-acre impoundment that has never been capped. Volunteer vegetation (including many trees) started growing at the site roughly 20 years ago, Wong said. Union Carbide is now finding that, within the upper 3 to 4 feet of material (where the trees are growing), the sludge has converted to a soil-like material, which is odorless from a chemical standpoint, though it does contain high concentrations of PAHs. Below 4 feet, however, the sludge is at roughly the same consistency as it was when discharged: it gives off a strong chemical odor, and still contains both volatile organics and PAHs. Wong said that Union Carbide has seen a "marked transformation" where vegetation is growing directly within the sludge. He said that the company believes that the trees have degraded the contaminants to a point where a safe soil cap now overlies the sludge. If the company created some drainage and provided a path for surface runoff, the trees would probably uptake all moisture that enters the basin (minus runoff). This impoundment now has a volunteer vegetative cap.

How to Bring Other Organizations into the Subgroup

Wong said that he contacted the Texas Natural Resources Conservation Commission and invited them to participate in the Subgroup. The Commission didn't have time to participate in this conference call, and Wong doesn't know whether or not it is interested.

Wong said he also contacted Scott Huling of EPA's Oklahoma office. Huling couldn't participate in the conference call, and asked Pivetz to sit in. Pivetz stated that Huling is interested in vegetative caps, and that both he and Huling plan to be active within the Subgroup.

Wong asked if anyone had a contact within the Interstate Testing and Regulatory Commission (ITRC). Rock said that he had spoken with the ITRC recently. The ITRC is doing a little phytoremediation work on metals uptake, Rock said, but hasn't yet gotten into organics or vegetative capping. Rock said that he would call his contacts to see if they would be willing to participate.

Phil Sayre asked Victoria Van Cappellen if she has run into anyone in Georgia who is interested in phytoremediation in general, or vegetative caps in particular. Sayre said he knows some people who work for the Georgia Department of Natural Resources; he may be able to get them involved with the subgroup, but doesn't know whether they're interested in phytoremediation. Van Cappellen said that she knows one person looking into the Brownfields issue in Atlanta; she'll check with that person.

Wong asked if there would be any benefit in involving personnel from other EPA regions. Rock stated that Rafael Casanova from Texas is getting very interested in vegetative caps and would probably participate in conversations. Rock also mentioned Rebecca Jamison, from EPA Region 9, and Steve Dwyer, a researcher from the Sandia Lab, who is doing a side-by-side cap analysis in New Mexico. Rock expressed concern that the group may have too many participants from the regulatory side and could use more participants from industry.

Wong said that personnel from Unocal are in the process of installing a vegetative cap; he'll contact them and attempt to stir up interest.

HELP Model

Wong discussed a paper, "Water Movement Through Soil Vegetative Landfill Covers," by Victor Hauser and Maurice Shaw, which was presented at the 1994 meeting of The American Society of Agricultural Engineers, in Kansas City, Missouri. The paper uses an Erosion Productivity Impact Calculator (EPIC) model to estimate how much water will infiltrate through sludge. Wong has the paper and will send copies to all who participated in the conference call.

The subgroup then discussed the HELP Model. Like the EPIC model, the HELP model is useful for calculating water filtration through vegetative caps. Wong said he's wondering whether it would be beneficial to improve the model so that it compensates for vegetation that has a higher leaf-area index. Rock said that such a modification would be extremely useful. The HELP model begins to fail when the leaf-area-index (LAI) gets to the range of 3 or 4. One of the things the Subgroup needs to do, Wong said, is modify the model to provide a reasonable evaluation of the vegetative cap. The model should allow for tall grasses with longer root systems and for trees. With regard to the EPIC model, the feedback Wong has received is that it is much more complex and more difficult to use than the HELP model. Wong doesn't believe the Subgroup should scrap the EPIC model, but he does think that efforts should be focused on HELP, especially since it is the standard for evaluating caps. Wong stated that modifying the HELP Model should perhaps be one of the Subgroup's long-term goals--something to factor into whatever research or technical development work the Subgroup undertakes.

EXISTING DATA

During the May 8 conference call, the subgroup had agreed to leverage its existing knowledge by gathering and interpreting available data from other sources. Wong asked where these data are. Are there any good data available? Participants offered the following responses:

• Rock said that he completed a literature search on the topics of landfill caps and covers. Rock found six or seven references to Steve Dwyer's work, and little else. A search on the topic of vegetative caps turned up nothing.

• Sayre said that a student at the TIO is also gathering existing literature on vegetative caps, and is struggling mightily. The student may come up with something that the group can use.

• Wong said that Union Carbide has experienced similar difficulties; the paper by Hauser and Shaw is one of the few sources of information the company has found. The company is in the process of gathering information at its one-acre site; a fair amount of data have been collected, and Wong hopes that the company will publish something later this year.

• Jackson mentioned a Chevron site in Richmond, California, that provides a good comparison of the effects of vegetation. Vegetation has been growing over half the site for 5 or 6 years, while the other half has been left bare. Company researchers have noticed an effect similar to the one Wong described, wherein the soil underneath the vegetation, once contaminated with petroleum, actually looks like topsoil again. Meanwhile, the soil on the other half of the site continues to look black and oily. Chevron hasn't done any monitoring of contaminant depths, though Jackson feels that the site could provide useful data.

• Wong spoke of a site in New York that the University of Texas's Ray Loehr has examined, where a hauler had dumped a known quantity of a known type of waste into a pit. Researchers have been monitoring the plume from the site for intrinsic remediation. Unfortunately, they now have removed the source, though it might be possible to review the data the researchers collected if there is any worthwhile information.

• Pivetz mentioned several studies done by Ray Loehr that contain at least a small amount of information on vegetation. Pivetz will look through the studies and try to make the information available.

SITE INVESTIGATION: FUNDING AND SCOPING FIELD INVESTIGATION/TESTING

Wong asked Sayre and Rock to describe how work is typically funded at RTDF field sites. Sayre said that RTDF studies are funded in a variety of ways. Of all the Action Teams, Sayre said, the most structured is probably the Bioremediation Consortium, which is headed by Dow Chemical, DuPont, and other companies. Sayre believes that members of this Consortium signed a 5-year contract, agreeing to contribute a certain amount of money and manpower. Other Action Teams typically do the best they can to raise money.

Sayre also mentioned Cooperative Research and Development Agreements (CRADAs) as mechanisms that often bind federal agencies to industry partners so that resources can be exchanged and ideas protected. EPA and the Air Force have signed CRADAs within the Bioremediation Consortium. Consortium members are also bound by a web of contracts--both with each other and with private consultants who work for the Consortium. And DOE gives money to the Consortium through a contract with the Consortium.

Rock said that EPA's Office of Research and Development has begun to use an internal grant program where EPA personnel can write proposals to obtain several available pots of money. The Ecosystem Restoration program has funds, and each Region has a certain amount of discretionary money. Rock said that EPA Region 9 has earmarked some money for vegetative cap studies, and he plans to talk to other Regions to see if they'd like to participate. Once the Vegetative Cap Subgroup has put together a proposal that RTDF is willing to support, he'll start asking around. Rock would like to have a proposal ready by the end of the fiscal year in September.

Sayre said that Greg Harvey should be alerted that the subgroup plans to prepare a proposal, since he "often has success finding available money."

Wong asked Sayre if the Subgroup needs to formalize some type of an agreement or commitment between members. Sayre said that it's up to the members: if the Subgroup can pull off a project without a formal agreement, then all the better. Quite often, Sayre said, projects become formalized because confidential information needs to be protected, or because of patent agreements. Also, grant proposals tend to formalize relationships automatically: someone offers a site, others offer funding, others offer manpower, and so on. What matters is that contributors make a commitment, and that all parties pull their weight within the group.

Sayre recommended that Wong speak with Dale Ellis of DuPont, a member of the Bioremediation Consortium, or Dave Major of Beak International.

Wong recommended that, during the next conference call, Subgroup members plan the major issues of the vegetative cap study proposal--sites to include, information that must be gathered, and so on--then start working towards some kind of formal commitment from participants. Rock stated that a CRADA can be an effective way to secure a variety of resources for a project.

WRAP UP

Wong said that he will structure an agenda for the upcoming conference call so that the Subgroup can formalize its direction and work towards preparing a proposal. The next conference call will take place on Thursday, July 24, from 11:00 a.m. to 12:30 p.m. (EST). A second conference call is tentatively scheduled for Thursday, August 14, from 11:00 a.m. to 12:30 p.m. (EST). These calls will be used to finalize a vegetative cap study proposal so funding can be investigated. There will be time for one additional conference call, if necessary, to prepare the proposal if it cannot be completed on August 14.