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

November 19, 1999
12:00-1:30 p.m.

On November 19, 1999, the following members of the Remediation Technologies Development Forum's (RTDF's) Phytoremediation Action Team, Total Petroleum Hydrocarbon (TPH) in Soil Subgroup, met in a conference call:

Phil Sayre, U.S. Environmental Protection Agency (EPA) (Subgroup Co-Chair)
Kathy Banks, Purdue University
Evelyn Drake, Exxon Research and Engineering
Steve Geiger, ThermoRetec, Inc.
Sam Jackson, State University of New York
Peter Kulakow, Kansas State University (KSU)
Bud Prevatt, Phillips Petroleum Company
C. M. (Mike) Reynolds, U.S. Army Cold Regions
Steve Rock, EPA
Tom Spriggs, Purdue University

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

UPDATE ON FIELD DEMONSTRATION SITES

The TPH in Soil Subgroup has created a field study program to evaluate how effectively plants degrade petroleum hydrocarbons across a range of test sites. Conference call participants provided the following site reports:

Site A

Peter Kulakow said that analytical results are available for Site A's time zero (T₀) and time one (T₁) sampling events.

Site B

Steve Rock said that samples were collected from Site B in April 1999 and October 1999. Preliminary TPH results are available for the April sampling event, but Rock is still waiting to receive the final results. Evelyn Drake said that she will call the Arthur D. Little (ADL) laboratory to find out when these data will be finalized and released.

Sites C, D, and E

Mike Reynolds said that grass is growing at Sites C, D, and E. The sites are fertilized once a year, he said, noting that a delay in growth at Site D may have been caused by overfertilization. At all three sites, Reynolds continued, samples are collected at the beginning and the end of the growing season. (The 1999 growing season has ended. T₁ samples have been collected from Site C. T₂ samples have been collected from Site D. T₂ samples will be collected from Site E after Thanksgiving. Reynolds agreed to send Kulakow a list of the sampling dates for each site.) Reynolds said that Battelle is performing contaminant analyses on the soil samples. Microbial analyses are also being performed; Reynolds and Duane Wolf are conducting plate count and most probable number analyses, and Microbial Insights, Inc., has been asked to perform phospholipid fatty acid analyses.

Site F

Sam Jackson said that willows, poplars, and grasses have been established at Site F. Biomass equations are being developed, he said, so that investigators can determine the aboveground biomass of these plants. Site F's T₁ soil samples were collected on November 16, 1999, and sent out for analysis. In addition, Jackson said, root samples were recently collected and sent to Kulakow. Kulakow explained that Site F consists of two distinct soil layers. The top layer, which is contaminated and about 6 inches in depth, was spread over another contaminated area. The latter has become known as the base layer. In the top layer, Kulakow said, the grasses have developed dense root networks, but the tree roots are not as dense yet. In the base layer, root systems were detected, but the bulk of the roots are historical remnants. (Some plants had been established in the base layer prior to the phytoremediation study. These plants were removed prior to initiating the Subgroup's field study, but some roots were left behind. These are decaying over time.)

Site G

Plants are growing at Site G, Kulakow said, but he was unsure how much growth occurred over the last month because the weather has been warm and dry. Site G's T₀ results have been finalized, he said; (1) average TPH concentrations are about 10,000 mg/kg, and (2) polycyclic aromatic hydrocarbons (PAHs) are present, but at concentrations below soil screening levels.

Site J

Reynolds said that plants have been established at Site J.

Site K

Kathy Banks, Tom Spriggs, and Rock described a phytoremediation study that is taking place at an MGP site. After hearing about the site, call participants agreed that it should be included in the Subgroup's field program and labeled "Site K." A variety of technologies are being tested at this site, Rock said, noting that land farming, bioslurry, biopiles, and phytoremediation are all being evaluated. For each technology, Banks said, nine treatment plots have been established. (Nine control plots have also been established.) Spriggs described the phytoremediation plots, noting that each of the nine plots has a mixture of:

• Poplar trees. Spriggs said that each phytoremediation plot, which is about 24 feet by 24 feet in size, has about 60 hybrid poplars. These trees, which were planted this year, are planted in rows; each row is about 3 feet apart, and the trees within each row are separated by about 3 feet. Such a tight planting schedule is being used, Spriggs explained, because investigators hope to maximize remedial benefits over a short time period. Significant pruning will be conducted next year, however. Spriggs said that the trees were fertilized and irrigated over the last year to make sure they exhibited strong growth. (Banks agreed to forward fertilization rates to Kulakow.) In the years to follow, Spriggs said, investigators will cut back on the amount of irrigation the trees receive. In general, the trees have been healthy, with less than 5 percent dying off. Significant die-off was observed, however, in a corner of one of the plots. Upon further investigation, Spriggs said, bricks and a blue precipitate were discovered in the subsurface under these trees. After reading some papers, he said, investigators determined that cyanide may be leaching from the bricks. (The cyanide could have been absorbed by the bricks when the site was manufacturing gas.) Steve Geiger told Spriggs that ThermoRetec, Inc., has worked on several MGP sites; for one site, the company is conducting a phytoremediation project to remediate cyanide in ground water. Geiger and Spriggs agreed to talk offline about cyanide contamination.

• Grass understory. Banks said that an understory of grass has been planted under the poplar trees. The first grass species planted at the site performed poorly; this may have been because the plants could not prosper under the poplars' shade or because they were unable to withstand the high concentrations of limestone in the site's soil. After realizing that the grass was not prospering, Banks said, investigators planted a perennial mixture. This is growing quite well.

Spriggs and Banks provided a brief description of the site's contaminant profile. Total PAHs are more than 1,000 mg/kg, Banks noted, and about 19 target PAHs have been identified. Banks agreed to send Drake a list of the targets for the PAHs. Some benzene, toluene, ethylbenzene, and xylene (BTEX) may be present at the site, Banks said, but this is not expected to persist in the soil for long durations.

Spriggs said that soil samples were collected from the phytoremediation plots in May 1999 and fall 1999. Samples were collected from three depths: 2 feet, 4 feet, and 6 feet. Within each plot, Spriggs explained, one sample—consisting of a homogenized composite of eight cores—was collected at each depth. Banks said that Battelle is analyzing the samples and that their list of analytes closely matches those at other Subgroup sites. One area in which Site K differs from other Subgroup sites, she said, is that biomarkers are not being evaluated. (Kulakow said that PAHs may be able to serve as biomarkers at Site K.) Banks said that Purdue University is performing detailed microbial characterizations of the soil.

Kulakow asked whether any root growth analysis has been performed at Site K. Banks said that it had not, but that she would be willing to collect some root samples if Subgroup members could describe a nonintrusive way of collecting the samples. Spriggs said that he hopes to excavate a tree near one of the plot boundaries so that he can evaluate rooting characteristics. He would like to determine whether poplar roots are able to branch out beyond the augured holes they are planted in.

Two other studies are being considered at Site K, Banks said, noting that both might be of interest to Subgroup members:

• Using phytoremediation as a polishing tool. Banks said that Purdue University is performing some greenhouse studies to evaluate whether phytoremediation is an effective polishing tool when it is used in a treatment train. Assuming that some positive results are demonstrated, Banks said, a field study might be initiated in the spring of 2000. This would involve taking materials that had not been adequately cleaned up using land farming or biopiles, spreading these materials over a plot, and then seeding the plot with a fast-growing grass.

• Wetland study. Banks noted that there is a wetland located next to Site K. Purdue University might initiate a field study in the wetland, she said, noting that Spriggs is performing some greenhouse studies in relation to this project.

Kulakow agreed to send Banks a site questionnaire. Banks will fill it out and return it to him promptly.

Other Potential Sites

Reynolds described two sites—both outside the United States—that might be good candidates for the Subgroup's field program. Both sites are contaminated with petroleum; jet fuel is prevalent at both, but crude oil is only present at one of the sites.

FACE-TO-FACE MEETING

Rock said that a three-day phytoremediation conference is being planned for early 2000. A variety of topics will be covered during the conference, Rock said, noting that one of the sessions will be allotted to the TPH in Soil Subgroup. Conference call participants expressed enthusiasm for a face-to-face meeting, saying that they will have plenty of data to share at the meeting. Rock said that he would like to hold the meeting in the Northeast in February or March 2000. Conference call participants suggested scheduling it in Philadelphia, Pennsylvania, in March 2000.

ACCOUNTING SYSTEMS—TRACKING COSTS AND PERFORMANCE

Phil Sayre said that Subgroup members have expressed a need for cost-tracking tools. Two potential accounting systems were described during the conference call:

• Geiger's framework. Geiger distributed a cost chart to conference call participants before the call. He said that this one-page chart, which was compiled from the Craney Island project's spreadsheets, could serve as a cost-tracking spreadsheet. On this chart, Geiger explained, costs are split into two categories—capital costs and operational costs—and several subcosts are listed under each heading.

• The Federal Remediation Technology Roundtable's (FRTR's) system. Sayre said that FRTR has provided a framework for conducting cost and performance evaluations. This accounting system can be found in a document entitled Guide to Documenting and Managing Cost and Performance Information for Remediation Projects (http://www.frtr.gov/remedstudies.htm). Sayre said that cost tables are presented in the document; many of the chart's cost categories match those presented in Geiger's framework. Sayre said that FRTR's accounting system has been used to evaluate 140 sites and 29 different technologies. If the Subgroup uses this system, Sayre said, it might be possible to compare phytoremediation to other technologies.

Geiger expressed interest in learning more about FRTR's accounting system. He suggested using it as a template and then modifying it to meet the Subgroup's needs. (Conference call participants recommended tailoring the spreadsheet so that it accounts for the length of time that is required to clean up a site by phytoremediation.) Geiger agreed to work with Kulakow and Sayre to develop a useful cost-tracking tool. This will be presented during the Subgroup's next conference call.

ANNUAL REPORT

Kulakow said that he will summarize the Subgroup's activities in an annual report. Before he can prepare such a report, however, he needs to receive (1) completed site questionnaires from all Subgroup members, and (2) guidance on the type of information that should be presented in the report. Responding to the latter, some conference call participants suggested drafting two reports; one would be available to the public and the other, which would provide much more detailed information and extensive data sets, would be available only to Subgroup members. Kulakow said that this topic will need to be discussed in more detail during the next conference call. Before members meet on the phone again, Kulakow will distribute a draft outline for the annual report.

NEXT CONFERENCE CALL

ERG agreed to set up the next conference call for December 16, 1999, between 12:00 and 1:00 EST. Discussions will focus on the next face-to-face meeting, cost and performance tracking systems, and suggestions for the annual report.

MISCELLANEOUS

Rock asked if anyone is interested in evaluating metals, saying that lead has been detected at one of his sites. Kulakow expressed interest, pointing out that some people have asked whether metals affect microbiological and phytoremedial activities. Banks asked if Rock would allow one of her students to collect samples for microbial analyses. Rock said that he would be amenable to this, but said that he would have to gain the site owners' permission first.

ACTION ITEMS

• Drake said that she will call ADL to find out when Site B's data will be finalized.

• Reynolds agreed to send Kulakow a list of sampling dates for Sites C, D, and E.

• Kulakow agreed to send Banks a site questionnaire. Banks will fill it out and return it to him promptly. She will include information about fertilization rates.

• Geiger and Spriggs agreed to talk offline about cyanide contamination.

• Banks agreed to send Drake a list of the target PAHs that are being evaluated at Site K.

• Geiger agreed to work with Kulakow and Sayre to develop a useful cost-tracking tool. (This will be presented during the Subgroup's next conference call.)

• Before the next conference call, Kulakow agreed to distribute a draft outline for the Subgroup's annual report.

• ERG agreed to set up the next conference call for December 16, 1999, between 12:00 and 1:00 EST.