U.S. EPA Bioavailability Workshop

AGENDA

Day 1: April 15
8:00 – 8:30     Keynote Address: Science Policy: Implementation of the Guidance and Impact on Cleanup Decisions. Larry Reed, U.S. EPA

8:30 – 8:45     Introduction

    Panel 1. Topic: In Vivo and In Vitro Assessment of Bioavailability of Soil Lead

    Questions and Issues for the Panel:

How well do in vivo models of lead bioavailability (e.g., swine bioassay) predict relative bioavailability of lead in children?
How well do in vitro bioaccessibility assays reliably predict results of in vivo relative bioavailability of soil lead in vivo models?
Are the soil samples that have been evaluated using the above assays adequately representative of the types of soils/lead species that can reasonably occur at sites? What would be a representative sample of soil types?
How can the in vivo or in vitro assays be improved to reduce uncertainty in predictions for lead?

Panel will be composed of speakers from Panel 1 and will be chaired by Gerry Henningsen, H&H Scientific Services click here for a summary of Mr. Henningsen's introductory comments

8:45 – 9:15     Presentation 1: Measuring bioavailability of soil lead in swine: Results of studies conducted by EPA Region 8. Bill Brattin, Syracuse Research Corporation  click here for abstract

9:15 – 9:45     Presentation 2: Bioassays: Past and future. John Drexler, University of Colorado  click here for abstract

9:45 – 10:00     BREAK

10:00 – 10:30     Presentation 3: Application of an in vitro extraction test to estimate lead bioavailability from soil: Lessons learned. Mike Ruby, Exponent  click here for abstract

10:30 – 11:00     Presentation 4: Assessing the oral bioavailability of lead in soil in humans. Mark Maddaloni, U.S. EPA  click here for abstract

11:00 – Noon     Questions/Comments from Audience

Noon – 1:00     LUNCH

1:00 – 1:15     Introduction

    Panel 2. Topic: Validation and Quality Assurance of Predictive Models of Metals Bioavailability

    Questions and Issues for the Panel:

What are the intended uses of the results of in vitro bioavailability models and what confidence is needed to support their application?
How should the validity of a predictive in vitro model for bioavailability be assessed?
What would constitute an adequate validation of an assay for site bioavailability of a metal?
In assessing the bioavailability of metals at a site where there are some in vitro and some in vivo split sample comparisons, what information will be needed to extrapolate from areas beyond those with split samples (if such comparisons can be made at all)?

Panel will be composed of speakers from Panel 2 and will be chaired by Larry Zaragoza, U.S. EPA

1:15 – 1:45     Presentation 1: Assessing model validation and quality management concerns in the review of predictive models of metals bioavailability. Larry Zaragoza, U.S. EPA   click here for abstract

1:45 – 2:15     Presentation 2: Estimating the oral bioavailability of As in soil. Mark Barnett, Dept. of Civil Engineering, Auburn University

2:15 – 2:30     BREAK

2:30 – 3:00     Presentation 3: What can we tell from a validated assay vs. one that has not been validated? Roz Schoof, Integral Consulting

3:00 – 4:00     Questions/Comments from Audience

4:00               Adjourn

Day 2: April 16

8:00 – 8:15     Introduction

    Panel 3. Topic: Characterization of Site Bioavailability of Metals (current focus is for site characterization of risk)

    Questions and Issues for the Panel:

How would sample locations and number for bioavailability estimation be determined to adequately capture or assess intra- and inter-exposure unit variability?
How should data from in vitro and/or in vivo bioavailability assays for metals be applied in human health risk assessment at contaminated sites?
How would one characterize a site with respect to factors that influence bioavailability (e.g., can we rank the intrinsic properties of the sample that influence bioavailablity)?
What are key areas for future research (uncertainty)?
How would this information be used in characterizing risk?

Panel will be composed of speakers from Panel 3 and will be chaired by Jeff van Ee, U.S. EPA

8:15 – 8:45     Presentation 1: In vitro determinations of arsenic bioavailability: Case study of application at a Midwest site. Teresa Bowers, Gradient Corporation  click here for abstract

8:45 – 9:15     Presentation 2: Benefits and limitations of EMPA techniques for metal speciation: The current best method. John Drexler, University of Colorado   click here for abstract

9:15 – 9:30     BREAK

9:30 – 10:00     Presentation 3: Soil lead bioavailability. Jim Ryan, U.S. EPA  click here for abstract

10:00 – 10:45     Questions/Comments from Audience

10:45 – 11:30     Summary Comments from Chairs of Panels 1, 2, and 3

11:30 – 12:30     LUNCH

12:30 – 12:45     Introduction

    Panel 4. Topic: Bioavailability White Paper for the Metals Framework

    Questions and Issues for the Panel:

What bioavailability methods or tools should be addressed in the Framework?
Have in vitro methods been developed to an appropriate degree to be discussed in the Framework?
What bioavailability issues should be stressed for human health risk assessment?
What bioavailability issues should be stressed for ecological risk assessment?

Panel will be composed of all speakers from Panels 1, 2, and 3 and will be chaired by Randy Wentsel, U.S. EPA

12:45 – 1:15     Presentation 1: Metals assessment framework. Randy Wentsel, U.S. EPA  click here for abstract

1:15 – 1:45     Presentation 2: Metals assessment issue paper: Bioavailability and bioaccumulation. Roman Lanno, Ohio State University  click here for abstract

1:45 – 2:45     Questions/Comments from Audience

3:00                  Adjourn