SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
IINERT SOIL-METALS ACTION TEAM
CONFERENCE CALL
2:00 p.m.–3:00 p.m.
October 14, 1998
On Wednesday, October 14, 1998, the following members of the IINERT Soil-Metals Action Team met in a conference call:
Bill Berti, DuPont Life Sciences (Co-chair)
James Ryan, U.S. Environmental Protection Agency (EPA) (Co-chair)
Rufus Chaney, U.S. Department of Agriculture (USDA)
Mark Doolan, EPA
Andrew Green, International Lead Zinc Research Organization (ILZRO)
Dean Hesterberg, North Carolina State University
Qi Xue, USDA
Also present was Christine Hartnett of Eastern Research Group, Inc. (ERG).
UPDATE ON ACTIVITIES AT THE JOPLIN, MISSOURI, SITE
Compiling Available Data
Bill Berti noted that a small group of RTDF IINERT Action Team members met in Kansas City, Missouri, on October 7, 1998, to discuss the Joplin data. He said a table was generated to compare data collected from animal dosing studies, in vitro tests, and plant studies. Rufus Chaney said the table offered encouraging findings for the 1% phosphoric acid treatment, noting that good agreement was demonstrated across the rat, swine, and in vitro data. Berti said the table does not include data from all of Joplin’s treatment plots. While in vitro and plant data have been collected for nearly all of the treatment plots, only a few of the treatments have been used in animal dosing studies. Berti said the table only includes data for those plots that were used in the animal studies. He recommended creating an additional table that summarizes the data collected from the other treatment plots.
At the October 7, 1998, meeting, Action Team members agreed to send Joplin data to David Mosby. Berti asked conference call participants to send him copies of their data as well, noting that he would help Mosby gather and compile the data.
Collection of Field Samples and a Discussion on Pending Animal Dosing Studies
On October 8, 1998, Berti, Mark Doolan, Qi Xue, Sally Brown, and Mosby traveled to the Joplin site to collect field samples. Berti said plant samples were collected from all of Joplin’s treatment plots, but that soil samples were only collected from a few. Chaney asked whether sufficient soil quantities had been collected to use in USDA’s rat dosing study. Doolan said soil samples were collected from the 0.5% and 1% rototilled phosphoric acid plots, and that a portion of these samples will be sent to Chaney after the University of Missouri processes the samples and removes what it needs for its swine dosing study. Chaney said he hoped to perform dosing studies using soil from a wider variety of treatment plots, including those with compost, iron treatment, hydroxyapatite, and triple super phosphate. He stressed that numerous treatments can be evaluated during rat studies because more soil can be fed to rats than to swine. Doolan reassured Chaney that additional samples could be obtained for the rat dosing study. He said he and Mosby visit the Joplin site on a frequent basis and would be happy to send Chaney additional samples.
Doolan noted that it would probably be best to collect soil samples immediately before initiating the rat study rather than storing them for long periods. He said that some investigators fear that soil properties change if the soils are stored too long. Andrew Green noted that the results of a toxicity bioassay study indicate that the holding time for frozen sediments should not exceed a month. After that time, toxicity evaluations start to fluctuate with the length of storage. (Green noted that the sediments used for the study were stored at 4 degrees Celsius in sealed buckets.) Green agreed to send a copy of this study to Berti, who will disseminate the report to the rest of the conference call participants. Dean Hesterberg said one of his graduate students addressed the sample storage issue in his Master’s thesis. Basically, by storing samples containing heavy metal sulfides under an oxygen scrubber (sodium sulfide solution) at 3 degrees Celsius, the acid-volatile sulfide contents of the samples were maintained at a constant level. Hesterberg said an excerpt from the dissertation report could be distributed to conference call participants if Berti added the following note: From Hansen, P.D. 1997. MS Thesis, North Carolina State University. (Berti already has a copy of the thesis.)
Chaney thanked Doolan for his offer to collect additional samples for USDA’s rat dosing study. Chaney said he is still securing the funds for the study. Ideally, Chaney continued, he plans to use staggered killing times so that numerous treatment plots can be analyzed in a single feeding study. Chaney asked Doolan when the ground at Joplin will become too frozen for sample collection. Doolan said he is optimistic that sufficient soil can be chipped or scraped together at any time of the year. Berti noted that other sampling activities are also planned at Joplin. He said he plans to collect soil and plant samples from the Joplin treatment plots on an annual or biannual basis.
Additional In Vitro and Plant Studies
Berti noted that he and Brown collected soil and plant samples from Joplin in May 1998. At the time, he said, they thought samples had been collected from all of the treatment plots. Berti sieved the soil samples and sent them to John Drexler for in vitro analysis. Brown performed total elemental analyses of the plant samples. Berti said that he has summarized the in vitro soil and plant data in an Excel spreadsheet. While compiling the data, however, he realized that data were missing for four of the Joplin plots. Berti said he collected samples from these plots on the October 8, 1998, site visit. He plans to dry the samples, screen them through a 250-micron sieve, and send them to Drexler for in vitro analysis. Berti said that Brown also plans to send the soil samples collected in September 1997 to Drexler so that the results obtained using her in vitro method can be compared against those generated using Drexler’s protocol.
Spectroscopic Analyses
Hesterberg said he wants to conduct X-ray absorption spectroscopic (XAS) analyses on soil samples from Joplin. Ideally, these analyses will provide information about how lead binds in soils receiving different treatments. Hesterberg noted that some difficulties have been encountered using XAS for lead in soils, but that the intended work will hopefully resolve some of these problems. Hesterberg hopes to evaluate soils from various Joplin treatment plots, and will only need about 2 to 3 grams of representative, sieved sample per plot. Chaney recommended that Hesterberg review Berti’s in vitro data spreadsheet to determine which treatment plots interest him the most. Berti agreed to send Hesterberg a copy of the spreadsheet.
Pending Reports
Berti noted that Brown, Chaney, and Xue released a report in April or May 1998. At the October 7, 1998, meeting, Berti said, Brown agreed to re-release the report after making some changes. Chaney said the changes will make the report more readable and understandable. In the original draft, he explained, it was not clear which samples were being referred to.
PROPOSED USDA STUDY
Chaney said he plans to initiate a study to determine whether mixtures of chicken litter compost and sludge compost effectively inactivate lead in urban soil. For this study, Chaney reported, he may use samples from Joplin and from a site in Baltimore, Maryland, and he plans to use in vitro tests rather than animal dosing studies to evaluate the treatments. He said he has been hesitant to initiate the study because the RTDF Action Team has not endorsed or validated any one particular in vitro method. Berti said it could be years before one method receives wide acceptance. Ryan recommended that Chaney proceed with the study. As long as the same method is employed on all of the samples, Ryan said, Chaney should be able to glean useful information. Chaney said he might use Brown’s in vitro method and noted that he has considered running his tests at a pH of 2.0 to 2.5.
CALCULATING BIOAVAILABILITY
Xue noted that Berti recently distributed an E-mail updating Action Team members about recent activities at Joplin. According to Berti’s E-mail, Xue said, data from the Joplin rat dosing studies indicated a reduction of lead bioavailability of about 55%. Xue asked whether Berti intends to publish this figure. If so, Xue cautioned, the Action Team should make sure that it is calculating bioavailability correctly. He noted that some methodological differences were identified at the October 7, 1998, meeting. While Stan Casteel’s original RBAF proposal recommended calculating bioavailability using a point estimate approach, Xue said, results from a recent “Red Cover” report suggest that Casteel is now using relative slopes to calculate bioavailability. Xue stressed that the Action Team must determine whether one method is more accurate and then agree to use one standard method. Failure to do so, Xue said, could leave the Action Team open to criticism.
Xue, Chaney, and Ryan agreed to review Casteel’s most recent report to make sure they clearly understand how bioavailability was calculated. Following the review, they will contact Casteel and discuss the bioavailability calculation. Once they have clarification, Chaney said, they will report their findings to Berti so that he can incorporate this information into the October 7, 1998, Kansas City, Missouri, meeting summary.
Berti asked how the figures cited in his E-mail would fluctuate if different calculations were used. Under the relative slopes method, Xue said, more reduction would be recorded in some treatments and less would be recorded in others. Berti then asked whether it would be correct to state that the rat dosing studies indicated more than a 50% reduction in bioavailability in the best treatment. Xue thought this statement was accurate.
TESTING OTHER TREATMENTS AT JOPLIN
Berti talked about two potentially useful treatments:
Berti noted that several private consultants and entrepreneurs are developing treatment mixtures that could prove beneficial to the IINERT RTDF Action Team. He asked conference call participants whether Joplin soils should be sent to these individuals for use in laboratory experimentation. Doolan said John Yang has multiple buckets of Joplin soil stored at the University of Missouri. The soil, Doolan explained, was collected during one of the first Joplin sampling efforts. Doolan agreed to contact Yang to ask whether the stored soil had been homogenized, sieved, or air dried.
Conference call participants agreed that Joplin soil samples could be sent to private consulting companies. Ryan and Doolan cautioned, however, that the RTDF Action Team needs to monitor new participants carefully. Ryan said researchers should be told that they need to adhere to the Action Team’s protocols. Additionally, Ryan said, new participants should be given a list of qualified laboratories. Doolan said new participants should be allowed to “play” with the Joplin soil samples as they see fit in their laboratories. To be taken seriously by the RTDF Action Team, however, new participants will need to prove that their treatment works by establishing a field plot at Joplin and performing analyses as dictated by the Action Team. (Eventually, Doolan noted, the Action Team will need to standardize its protocols.) Doolan noted that there are about 30 to 50 empty plots at Joplin that could be used to test additional treatments.
Doolan said that he and Mosby have been approached by Sevenson Environmental Services, Inc. on several occasions. According to Doolan, the company has expressed interest in establishing a plot at Joplin, but is not willing to divulge information about its patented treatment mixture. Doolan asked whether the Action Team wants to welcome new participants if they are unwilling to share information. He said that, from his perspective, little is accomplished if an effective treatment is discovered but cannot be distributed widely. He said the goal of the RTDF is to distribute technologies to many people rather than to simply promote a specific vender. Berti said he was not opposed to allowing vendors to experiment with patented treatment mixtures and noted that other RTDF groups have dealt with this issue. Berti said allowing vendors to participate could be beneficial, but he stressed that the RTDF Action Team should not be expected to subsidize the vendor’s research and development. Berti suggested that vendors should be expected to pay RTDF dues and/or fund their own animal dosing studies. Berti agreed to draft some guidelines for vendor participation.
ILZRO’S REQUEST FOR PROPOSALS (RFP)
Green said that at a workshop in Berkeley, California, in 1997, ILZRO concluded that a literature review needs to be performed on worldwide remediation projects. According to Green, ILZRO has decided that the review should cover previous and current reports as well as published and unpublished projects. Green said that ILZRO plans to hire a contractor to perform the literature review and that a draft RFP has already been prepared and presented to a group of six or seven scientists. The scientists, Green said, recommended formulating a matrix listing the type of data to be collected during the review, and they also compiled a list of recommended parameters and submitted these to Yaco Vangrosveld. Once the matrix is finalized, Green reported, the RFP will be distributed to those contractors who attended ILZRO’s Berkeley meeting as well as other recommended contractors.
ENVIRONMENTAL RESTORATION PROJECT
Berti noted that Doolan, Mosby, and Brown may conduct revegetation projects, including biosolid field studies, near Joplin, Missouri. Berti said the Action Team should start thinking about whether to interface with these restoration projects. He added that much work is being done in this area. Chaney agreed, noting that USDA is participating in a project with Harry Compton and that the University of Washington has initiated several projects under the direction of Brown and Chuck Henry.
COMMUNICATION
To date, Berti noted, he has distributed reports to Action Team members via E-mail attachments. He said he could have these reports posted to a protected area of the RTDF Web site if participants preferred to use the Web site. Conference call participants said they preferred to receive attachments. Chaney reminded participants that draft reports should clearly indicate that they have not been peer reviewed and that they are not meant for widespread distribution. Berti agreed and said reports would only be sent to those Action Team members who receive notification of conference calls.
MISCELLANEOUS
Berti said that the draft summary of the October 7, 1998, meeting will be available soon.
Berti noted that the American Society of Agronomy, the Soil Science Society of America, and the Crop Science Society of America are meeting in Baltimore, Maryland, during the week of October 19, 1998.
Chaney noted that a poultry manure conference is being held in Fayetteville, Tennessee, during the week of October 19, 1998. Doolan expressed interest in this topic and asked for additional information. Chaney agreed to forward a Web site address to Doolan and Mosby.
NEXT CONFERENCE CALL
Berti said the next conference call is scheduled for November 18, 1998.
ACTION ITEMS