SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
IINERT SOIL-METALS ACTION TEAM
CONFERENCE CALL

2:00 p.m.–3:00 p.m.
July 20, 1998

On Monday, July 20, 1998, the following members of the IINERT Soil-Metals Action Team met in a conference call:

Bill Berti, DuPont Life Sciences (Co-chair)
Mark Doolan, United States Environmental Protection Agency (U.S. EPA)
Dean Hesterberg, North Carolina State University (NCSU)
Gary Pierzynski, Kansas State University (KSU)

Also present was Audrey Wagenaar of Eastern Research Group, Inc. (ERG).

SAMPLE COLLECTED FROM KANSAS ARMY AMMUNITION PLANT AT PARSONS

Bill Berti inquired about the progress Andrea Austin had made regarding shipping soil samples from the Kansas Army Ammunition Plant to Jim Ryan. Gary Pierzynski stated that he had spoken with her and that, although she had screened the soil and put it into a barrel, there had been problems with shipping the barrel and she had been forced to remove the soil from the barrel and run it through the mill rather than ship it. Berti inquired if the shipping problem had been associated with cost and indicated that he had given Austin his credit card number to cover the cost of the shipping. Pierzynski stated that he thought the problem with the shipping lay more with the classification of the soil (i.e., hazardous waste) than with cost.

UPDATE ON ACTIVITIES AT THE JOPLIN TEST SITE

Berti noted that he and Sally Brown had collected samples from the Joplin field site at the end of May. Berti indicated that these soil samples had been digested and that total elemental analysis had been conducted at his laboratory (DuPont) but that he had not yet had a chance to summarize the results. Berti also sent some soil subsamples to Dr. John Drexler at the University of Colorado, who will conduct the in vitro test that has been developed by the Solubility Bioavailability Research Consortium (SBRC) on these samples. Berti stated that some of the plant samples had been digested by Brown’s laboratory (U.S. Department of Agriculture), but he is not sure how much progress she has made with these samples as she could not attend today’s meeting.

Pierzynski asked Doolan what his thoughts were about making a decision about Joplin. Doolan replied that he does not want to make that decision based on the single soil sample that was fed to swine. Doolan had hoped that the SBRC in vitro method would be validated so he could sample 20 to 30 areas on the site to determine the variability in bioavailability across the site. Doolan has delayed the decision, waiting for the SBRC in vitro method validation. Doolan spoke with Dave Mosby (Missouri Department of Natural Resources) this morning about collecting some additional soil samples from the mined area, and doing another dosing study to confirm the results of the earlier study, if the SBRC in vitro method is not validated.

Doolan stated that he had received data from Black and Beach and that he needed to determine the number of homes in the mined area of the site that have soil lead levels between 600 and 800 ppm. The lead cleanup criteria at the site has dropped from 800 ppm to 600 ppm due to a higher bioavailability of lead (40 percent versus 30 percent) than was originally assumed. A participant asked what the 600 ppm cleanup criteria was based on, as the default in the IUBK model would be 400 ppm. Doolan replied that they had changed several parameters, not only bioavailability, as the result of a demographic survey and site specific data. In response to another participant’s question about how this cleanup criteria was being received by another EPA office, Doolan replied that while most people found the proposed lead cleanup level (600 ppm) to be acceptable, a few ultraconservatives wanted unrealistic cleanup levels of 100 ppm. Berti asked if residential areas would be sampled.

TREATMENT INCORPORATION TECHNIQUES

Berti asked Doolan if Mike Ruby had contacted him regarding the incorporation of amendments, particularly phosphorus, used at the Joplin site. Doolan replied that had not heard from Ruby yet. Berti stated that Ruby may have tried to call Mosby instead. Berti said that he thought the work that was being conducted at Trail Ridge, British Columbia, by a contractor, Lane Tickanen, who attended the IINERT meeting in Las Vegas. Berti indicated that Mosby had thought that there was more than one contractor involved and that Tickanen was involved in the research and development at the site. Berti asked the other participants if they knew anything else about the site. Doolan replied that he knew that bioavailability experiments were being conducted at the site. Berti then asked Doolan if he knew whether multiple contractors were involved and, if so, whether Exponent was among them. Doolan replied that he did not know but that he had a quarterly report he had not reviewed recently. Doolan had heard that they were having little success at the site. A participant asked if duplication was a problem. Doolan responded that it was and that the site was much like Joplin in that less reduction than was expected was observed. He did not know any specifics, however.

TOXICOLOGY EXCELLENCE FOR RISK ASSESSMENT GROUP REVIEW (TERA REVIEW)

Berti stated that a group of toxicologists, the Toxicology Excellence for Risk Assessment (TERA) Group, reviewed the SBRC in vitro, glycine-based gastric test and that the results were posted on their Web site at http://www.tera.org/news/april27s.htm. Berti offered to send the summary to interested participants, because it is quite long. Berti indicated that the primary recommendation was that more information about characterization of test soils, such as pH, particle size, catio exchange capacity, and mineralogy of the non-lead containing fraction is needed.

Doolan asked if the team members identified any areas of the test that could be improved. Berti indicated that the TERA group commented on six different questions and referred participants to the summary review. Doolan then inquired if the TERA group had only examined the method.

Berti referred the participants to the part of the TERA summary where the panel was divided about whether the SBRC test was valid for lead and indicated that a better understanding of the in vivo data for arsenic was necessary before proceeding with this method.

A participant indicated that the SBRC is planning to meet on August 11 and will discuss the TERA review and the current status of the in vitro method validation. Pierzynski indicated that people are moving ahead using the latest version of the method because it correlates well with lead bioavailability measured using the swine model. He also indicated that adjustments can be made as the knowledge base develops.

Doolan referred the participants to a study by Blanchar and Yang, which did not correlate with the in vivo swine model. Pierzynski stated that this study used treated samples, that have not reached a steady state, thereby causing different results in swine than expected. Doolan commented that the in vitro studies showed a 90 percent reduction of lead in treated samples compared to a 30 percent reduction in the swine studies.

Doolan indicated that EPA is also trying to validate the SBRC method. Doolan stated that Drexler had made several toxicity characteristic leaching procedure (TCLP) extractors and had sent them to the laboratories used by EPA. Doolan stated that the first round of samples has gone to the laboratory and been analyzed. The second group of samples is being analyzed. Kim Brown of EPA’s Office of Research and Development (ORD) laboratory in Las Vegas has analyzed the first set of samples using the SBRC in vitro method and is waiting for more samples from Drexler. A total of 20 to 30 samples will be analyzed by the SBRC in vitro method within the next few months at the three separate laboratories; using 20 to 30 samples. Doolan indicated that the arrangements after completion of the analysis were unclear and said he thought that the results would be sent back to Drexler, who would write a report to be released by the end of the year. Doolan is interested to know whether the ORD research staff felt that the results from the SBRC in vitro method and the swine studies were correlated.

David Drake in Doolan’s office has already collected about 100 samples from the Cherokee County site in Kansas and has sent them to Ken Brown in Las Vegas. Ken Brown ran such standard tests as total metals and other soil characterizations on all these different samples. Ken Brown had intended to conduct the in vitro method on all the samples to determine the variability across Cherokee County. Doolan indicated that there was an agreement between EPA Region 7 and the ORD Las Vegas laboratory to conduct these analyses on all the mine sites in EPA Region 7. Doolan indicated that EPA Region 7 is also planning to collect samples in Jasper County and the Big River site on the eastern side of the state and perhaps at several other sites to determine the variability in the bioavailability at all the mine sites in EPA Region 7.

Pierzynski asked Doolan if he knew what is required to prove that in vitro tests are acceptable. Doolan responded that even if the three labs show good agreement with each other, agreement will still need to be demonstrated between the overall results from the three labs and the swine dosing studies. Hesterberg stated that he thought that the correlation was good at the moment. Doolan countered that the experts in EPA Region 8 who have examined the available data feel that the results do not correlate that well. A year ago, when Ruby or Drexler presented all this data, the experts scrutinized the data and it became apparent that some outlying data had been rejected. The data set was so small that EPA included the outlying data and repeated the analysis. Dr. Chris Weis of EPA Region 8 had found that the data did not correlate very well, but there is still some discrepancy about this issue.

Pierzynski asked the participants if they knew other options to in vitro testing. There are two other options—use the default Pb-bioavailability or conduct an animal study.

PHOSPHORIC ACID

Doolan indicated that EPA Region 7 was not having the success it had hoped for at the Jasper County (Joplin, Missouri) site, and he was wondering if vendors like Severnson may have more effective agents than phosphoric acid. Severnson had been the only vendor to come to the site to date and demonstrate its products. Doolan would like to encourage other vendors to do the same.

Doolan indicated that his most recent in vivo swine studies using iron-rich soil from Berti and Brown’s plots at Joplin indicated that this soil had a higher bioavailability than the untreated control. A report on the study has not yet been released, but Doolan is very concerned about why the addition of iron would raise the bioavailability. He asked the other participants if they had ideas about what may be occurring at this site. Blanchar had suggested that the iron may have decreased the pH of the soil, causing acid conditions. Hesterberg suggested that iron reduction may be taking place and suggested using alumina as a sorbent. Another participant thought that if the increased bioavailability was due to a redox effect, such an effect would not be expected for aluminum. This participant was also concerned that high aluminum levels could be toxic to plants if the soil pH was below five.

Doolan provided some information about a mine waste project Dave Mosby is working on in the Joplin, Missouri area. This project is examining revegetation issues using different kinds of compost to establish plants in mine waste materials. Mosby added phosphoric acid to the plots to determine its effect on the mine waste. Mosby installed some minipiezometers to collect ground water downstream of his treatment plots. Mosby found that after the addition of phosphoric acid the concentration of metals in the ground water increased significantly. Mosby determined that the phosphoric acid reacted well with the top 2 to 3 inches of the mine waste but that hydrogen ions passed through the mine waste, dissolved out of the metals, and transported the metals to the ground water. Mosby now has some serious reservations about using phosphoric acid in soils that do not have high organic contents, such as mine wastes. Pierzynski asked how deep the ground water was in the area and Doolan replied that it was shallow, about 2 to 3 feet deep in most places.

MISCELLANEOUS

Doolan indicated that he would like to determine how much the bioavailability changes across the whole Midwest. Because bioavailability significantly affects cleanup levels, Doolan would like to assess how bioavailability changes in different geological settings and, more specifically, across each site. Doolan provided the example of the Big River site, in which the IUBK model indicates that the concentrations of lead found in residential yards should cause 25 to 30 percent of the population to have blood lead levels exceeding 10 mg/deciliter. Instead, only 17 percent of the population shows elevated blood lead levels. Because the sample size of children tested was large, Doolan thinks that the bioavailability of the soil is affecting the blood lead levels.

Berti asked the participants if they had seen the research section of the latest copy of Environmental Science and Technology (July 1, 1998 edition) in which there is an article about lead exposure. Another article of interest in the same issue pertains to the use of “dryer lint” to measure lead exposure. The group indicated that this technique may better reflect occupational lead exposure rather than environmental exposure. The second article is only available on the Web version of the magazine. Berti will fax a copy of the article to Doolan.

Pierzynski indicated that he is going to attend an international soil science meeting in France and thought that it might be a good place to solicit vendors for the Joplin (Jasper County, Missouri) project.

NEXT CONFERENCE CALL

The participants agreed that future conference calls will be held on the second or third Wednesday of each month. The next conference call is scheduled for August 19, 1998, between 2:00 and 3:00 Eastern Daylight Time.