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

October 9, 1997

Updates

Dave Mosby (Missouri Department of Natural Resources) updated us on the status of the swine dosing study to determine soil-Pb bioavailability of samples treated at the Joplin field research site (JFRS) with 0.5 and 1.0% phosphorus (P). Preliminary data from Stan Casteel (University of Missouri) indicate that the reduction in soil-Pb bioavailability as a result of adding P was not as good as demonstrated with the in vitro test. Additionally, reductions in soil-Pb bioavailability appear somewhat lower than that seen in the laboratory treated soils. These samples were from treatments established at the JFRS in March 1997 and collected from the field in July 1997. There are plans for another round of swine dosing studies on one soil. The discussion now is which of two soil treatments to use: the Fe + P field treatment as first proposed or a 1 to 1.5% P treatment carried out by Bob Blanchar/John Yang (University of Missouri) that has gone through 12 wet/dry cycles at 55⁰C. The latter is the more likely treatment of choice unless someone else is willing to help fund the other soil treatment, too.

Soil questionnaire

We are looking for comments and suggestions to the soil questionnaire that went out recently. It will be sent out to the full IINERT membership, accompanied by a cover letter.

Other Field Sites

Harry Compton (U.S. EPA) suggested a location for another possible field site located in Harriman, Utah, where many square miles of land are contaminated with Pb from a smelter. Average Pb concentrations are alleged to be 0.8%. It is not clear what the primary driver is - probably children's blood-Pb levels, although Harry was unsure of the data. Harry was going to give the soil questionnaire a try, using it to begin gathering more information on this area.

Bioavailability Conference

'Bioavailability - Quantifying the Real Toxicity of Common Soil Contaminants' will be held December 11 and 12, 1997 at the Raddisson Resort in Scottsdale, AZ. Those scheduled to speak include Stan Casteel, Dave Mosby, John Drexler (University of Colorado-Boulder), and Mike Ruby (PTI Environmental Services). For more information check out the web site at <http://www.ibcusa.com/conf/bioavailability/>.

SBRC

Bill Berti (DuPont) talked about some of the work of the Solubility Bioavailability Research Consortium (SBRC). The SBRC is a collaborative effort among academics, consultants, regulators, and the regulated community to develop and validate methods for determining the bioavailability of hazardous substances in contaminated soils. Participants in the SBRC who also have participated in the IINERT RTDF include John Drexler, Mike Ruby, and Bill. In an attempt to determine the most appropriate pH for a simplified in vitro method that uses glycine to buffer the solution, all materials that previously had been dosed to swine were run through the test at two pH values: 1.5 and 2.5. The test worked well for Pb. At pH 1.5 the in vivo to in vitro correlation yielded an r² = 0.88 (n = 14), and at pH 2.5 it yields r² = 0.85 (n = 14). These data indicate that the new method works well for Pb, and possibly slightly better at a pH value of 1.5. The method does not appear to work as well for As as it does for Pb. At pH 1.5 the in vivo to in vitro correlation for arsenic yields an r² = 0.44 (n = 8), and at pH 2.5 it yields an r² = 0.12 (n = 8). However, because there are relatively few arsenic data points, it is difficult to state conclusively whether the test will work for arsenic The plan of the group at this time is to proceed with the formal validation of the test for Pb, while simultaneously collecting arsenic data.

Next conference call . . .

. . . is scheduled for Thursday November 13 from 1:30 to 2:30 eastern standard time.