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

Kansas City, Missouri
May 14­16, 1997

FIELD TRIP TO JOPLIN FIELD STUDY SITE

On May 14, 1997, members of the Remediation Technologies Development Forum (RTDF) In-Place Inactivation and Natural Ecological Restoration Technologies (IINERT) Soil-Metals Action Team visited the Joplin, Missouri, field study site. Mining was conducted at this site until the early 1900s, followed by smelting operations until the 1940s. Primary soil contaminants are lead and zinc, with lead concentrations ranging from 1,000 parts per million (ppm) to 5,000 ppm. The one-acre test site is in an urban area, three to four blocks away from the site of the primary smelter. Field studies at the site are currently being conducted by the U.S. Environmental Protection Agency (EPA), Missouri Department of Natural Resources (MDNR), University of Missouri, and the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS). Studies involve treatment of contaminated soil with various amendments that may reduce the bioavailability of lead in soil. ⁽¹⁾ The various studies underway at this site were described to the entire Action Team during its meeting the following day.

ACTION TEAM MEETING
Dr. Bill Berti (Dupont Central Research and Development)
Dr. Jim Ryan (EPA)

Dr. Berti and Dr. Ryan, the meeting co-chairs, welcomed the group. The attendees introduced themselves and described their interest in in situ soil-metals remediation. A list of attendees appears at the end of this meeting summary. Dr. Berti explained that the RTDF allows government and industry to work together to develop and improve environmental technologies so that hazardous waste cleanup goals are met in a safe and cost-effective manner. He noted that the following points had become apparent over the course of the RTDF process:

• There is a large leap from agreements between organizations in principle to final contractual language.

• No agreement is perfect, but agreements can be productive and successful.

• Programs need resources and a driver.

• Technical and legal discussion must occur on parallel paths.

• Motivating issues are important.

The agenda for the meeting included presentations on:

1. A study to evaluate the potential and quantify the efficacy of phosphoric acid amendment, and to measure the post-treatment bioavailability of lead in soil from the Joplin site, presented by Dr. Bob Blanchar and Dr. John Yang, University of Missouri;
2. A study to determine the bioavailability of lead in contaminated soil from the Joplin site through a juvenile swine model, presented by Dr. Stan Casteel, University of Missouri;
3. A study to determine the relative efficacy of various amendments and application techniques in reducing the levels of bioavailable lead in soil at the Joplin site, presented by Mr. David Mosby, Missouri Department of Natural Resources, and Dr. Sally Brown, U.S. Department of Agriculture, Agricultural Research Service;
4. A study to design, develop, and calibrate an in vitro method of measuring lead bioaccessibility and to study the effects of various parameters on bioaccessibility, presented by Ms. Sarah Jones, University of Colorado, and Mr. Mark Doolan, U.S. EPA Region 7.

RESEARCH AREAS

Dr. Berti presented six hypotheses that are the basis of the Action Team's efforts:

• Soil lead bioavailability to humans can be determined by surrogate relationships among animal models and confirmed through biological, chemical, and physical tests.

• Good correlations exist between soil components (e.g., lead species, non lead-containing components) and soil lead bioavailability. These correlations will determine the short- and long-term stabilities of soil lead components.

• Engineered additions of materials to lead-contaminated soils will induce the formation of less bioavailable lead forms, providing a practical approach to in-place inactivation.

• The research and development of IINERT for soil lead extends to other soil contaminants as well.

• Prior to widespread use of IINERT approaches to remediating soils containing lead, public trust must and can be garnered through careful scientific studies.

• IINERT is compatible with maintaining or improving ecosystem health.

The Action Team broke into three groups to discuss the first three hypotheses, focusing on the research questions to be answered, potential approaches, and resources (e.g., in-kind, funds, patents) required for addressing each hypothesis. The product of these discussions will be incorporated into a document for presentation to the RTDF.

Ms. Carolyn Perroni (Environmental Management Support, Inc.) asked members to inform her about any Web sites that are relevant to the Action Team's activities. Her goal is to develop the Action Team's own RTDF Web page as a resource linked to as many information sources as possible.

⁽¹⁾    Dr. Stan Casteel, University of Missouri, provided the following definitions. Bioavailability is the ability of a compound (e.g., lead) in an oral dose (e.g., food, ingested soil) to be absorbed into the systemic circulation. Absolute bioavailability refers to the fraction of an oral dose that is absorbed into the bloodstream. The absolute bioavailability of lead in food/water is currently considered by EPA to be 50 percent, while the value for lead in ingested soil is considered by EPA to be 30 percent. Relative bioavailability is the ratio of absolute bioavailability of a compound in an oral dose to its absolute bioavailability in a reference dose (e.g., the bioavailability of lead in soil relative to lead in food/water would be 60 percent). Site-specific relative bioavailability values for contaminated soil may differ from these default assumptions and allow enhancement of the risk assessment process.

RTDF IINERT Soil-Metals

Action Team Meeting

Participants

*Speaker