PARENT SESSION
PW10 - Ecological Risk Assessment
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P834) Using a Multiple-Model Approach and 3-Dimensional Visualization for Perchlorate Risk Assessment.
Albers, Eric*,1, Dixon, Ken1, 1 Texas Tech University, Lubbock, Texas, USA
ABSTRACT- When conducting a site-specific risk assessment it is important to not only accurately determine the risk to target organisms but also be able to convey this information to a wide, often non-scientific, audience including risk managers, regulators, and other decision makers. By combining environmental transport models with an animal movement model and a physiologically based toxicokinetics (PBTK) model that has an embedded effects model, it is possible to arrive at a more accurate determination of risk compared to just a maximum-dose approach. Initial multiple-model simulations have calculated organ concentrations as much as two orders of magnitude lower than those found with the maximum-dose approach. Utilizing 3-dimensional visualization techniques, commonly found in engineering and entertainment, then allows us to present large amounts of data as easily understood simulations. The Longhorn Army Ammunition Plant (LHAAP), in Karnack, TX, was studied for the impacts of perchlorate on thyroid hormone secretion in the channel catfish (Ictalurus punctatus). We compared the PBTK output and hormone secretion rates for the multiple-model approach to that of a single model PBTK using the total maximum environmental concentration and the maximum environmental concentration at each time step as the inhaled dose. The organ concentrations and subsequent impact on hormone secretion of the multiple-model approach were significantly lower than the other approaches. In addition to the standard graphs a 3-dimensional simulation of contaminant concentrations in each organ compartment and the subsequent effect on hormone secretion rates was created using MAYA from AliasWavefront. This end product is more accurate and easier to understand than conventional methodology.
Key words: risk assessment, 3-dimensional visualization, PBTK, perchlorate