SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
IN-PLACE INACTIVATION AND NATURAL ECOLOGICAL RESTORATION
TECHNOLOGIES SOIL-METALS ACTION TEAM
CONFERENCE CALL

January 31, 2000
4:00 p.m.-5:00 p.m.

On Monday, January 31, 2000, the following members of the In-Place Inactivation and Natural Ecological Restoration Technologies (IINERT) Soil-Metals Action Team met in a conference call:

Bill Berti, DuPont Central Research and Development (Action Team Co-Chair)
James Ryan, U.S. Environmental Protection Agency (EPA) (Action Team Co-Chair)
Sally Brown, University of Washington
Judith Hallfrisch, United States Department of Agriculture (USDA)
Mike Ruby, Exponent Environmental Group

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

ACTIVITIES RELATED TO THE JOPLIN, MISSOURI, SITE

The conference call participants talked about the Joplin, Missouri, site. They noted that several analyses and studies will be initiated in the near future; data will be generated using plant extraction studies, in vitro analyses, and animal dosing studies. In addition, participants talked about three reports that will be written about the Joplin site in the near future.

Plant Extraction Studies and In Vitro Analyses

Soil samples were collected from the Joplin site in October 1999; Bill Berti and Sally Brown plan to conduct the following analyses on them:

• Simple plant extraction. Berti said that this extraction is being performed to quantify how much contaminant can be absorbed by plants. The analyses will revolve around lead uptake, although some other metals may be evaluated as well. Berti said that samples will be extracted using a salt solution and then filtered. Berti noted that he and Brown have discussed using a 0.01 Molar (M) calcium nitrate solution; this solution will be easy to use and will mimic the soil conditions that surround plant roots. Berti was not sure whether this solution has been used before, but Brown said that she thinks she will be able to find a reference for it. James Ryan asked whether Berti and Brown have considered using a potassium nitrate extraction solution; he said an article in Environmental Science and Technology summarizes how one group measured metal concentrations using a 1.01 M potassium nitrate extract and anode stripping voltametry. Berti said that he had heard of the study, but that he thought it focused on cadmium rather than lead. Nevertheless, he agreed to perform a literature search to determine whether studies have been performed using the potassium nitrate extraction solution to evaluate lead.

• In vitro analysis. Berti and Brown said that physiologically based extraction tests (PBET) will eventually be performed on the soils that were collected in October 1999. This sparked a discussion about which methods and protocols are most appropriate to use for in vitro analyses. Conference call participants recommended using SBRC's protocol, but using a higher pH. The SBRC in vitro protocol that is currently being validated is performed at a pH of 1.5. Brown said that performing the test at pH 1.5 fails to demonstrate treatment effects even though such effects are apparent when the treatments are evaluated by other means, such as through plant analyses or animal dosing studies. Mike Ruby said that better correlation has been observed on treated samples when the in vitro test has been performed at a pH 2.3 or 2.5. Therefore, Berti and Brown agreed to use a higher pH when performing in vitro analyses on the October 1999 soil samples.

Animal Dosing Studies

During a previous conference call, Judith Hallfrisch said, the Action Team decided it would be beneficial to conduct rat dosing and swine dosing studies simultaneously. By feeding the same samples to both animal populations, she explained, investigators will be able to determine whether correlations exist between the swine and rat models. (The samples used in the studies will be collected from Joplin.) Ryan said that he will call Mosby to find out whether the swine study has been scheduled; he will forward Mosby's response to Hallfrisch.

Reports

Conference call participants discussed three reports that Subgroup members plan to write about the Joplin site. These efforts will be lead by:

• Sally Brown. Brown plans to write a manuscript that summarizes plant bioavailability data and in vitro test results. She said that she will complete the manuscript after in vitro analyses are performed on the soil samples collected in October 1999. By waiting for these results, she said, she will be able to include three years' worth of data in the report. She did note, however, that the in vitro tests collected over the three-year period have not all been performed at the same pH; this will need to be made clear in the report.

• David Mosby. Ruby said that Mosby plans to summarize much of the Joplin data in his Master's thesis, noting that Mosby plans to release a draft to EPA and the IINERT Action Team in late January or early February. Berti agreed to call Mosby for an update on the report's status.

• Mike Ruby. Ruby said that Exponent Environmental Group has analyzed soil samples from Joplin using the SBRC protocol at several different pHs (i.e., 1.5, 2.0, 2.3, and 2.5). The soil samples that were analyzed, he explained, were also fed to swine as part of an animal dosing study that was overseen by Dave Mosby and conducted by Stan Casteel at the University of Missouri. Ruby said that the in vitro data have already been distributed to IINERT Action Team members, and that they were forwarded to Mosby so that they could be included in his Master's thesis. Ruby recently learned, however, that Mosby will not be incorporating the data into the thesis report. Therefore, Ruby proposed publishing the data himself; more specifically, he proposed writing a paper that compares the in vitro data against the swine dosing study results. Ryan suggested contacting EPA's Mark Doolan to ask for permission to publish the swine study results. (EPA Region VII funded this study.) Ruby said that he would do so.

Hallfrisch said that USDA has initiated some rat dosing studies that do not involve samples from Joplin. In these studies, she said, pure lead minerals were fed to rats. (Some of the rats were fed lead carbonate; others were fed lead sulfide. Some of the diets included hydroxy appetite, but others did not.) Hallfrisch said that blood, stomach, small intestine, large intestine, and feces samples have been collected and that these are being analyzed. Ryan said that he will run in vitro tests on the samples that USDA used in these studies; he will use the SBRC protocol at a variety of pH levels (1.5, 2.0, and 2.5).

ACTION ITEMS

• Berti and Brown will perform simple plant extraction tests and in vitro analyses on soil samples that were collected from Joplin in October 1999. Before initiating the plant extraction tests, Berti will perform a literature search to determine whether other groups have used potassium nitrate as an extraction solution. Brown said that she thinks that calcium nitrate has been used as an extraction solution in some studies; she agreed to search for a reference for such usage.

• Hallfrisch noted that rat and swine dosing studies are supposed to be held concurrently. Ryan said that he will call Mosby to find out whether the swine study has been scheduled; he will forward Mosby's response to Hallfrisch.

• Conference call participants said that Mosby is summarizing much of the Joplin data in his Master's thesis. Berti agreed to contact Mosby for an update on the report's status.

• Ruby said that he would like to write a paper that compares the data collected from in vitro tests with that collected during a swine dosing study. Because the latter was funded by EPA, Ruby agreed to contact EPA's Mark Doolan to ask for permission to publish the swine study results.