POWRE: A Population Approach to Modeling Contaminant Bioaccumulation

Tulane University, New Orleans LA

Investigators

Abstract

0074934 Watanabe The objective of this research project is to evaluate the feasibility of a Bayesian approach to understanding and quantifying the impact of population variability on the biological fate of environmental contaminants. In past studies of contaminant bioaccumulation, emphasis has been placed on the average concentration expected for a population of organisms, using average biological and environmental input values to model the process, and the goodness-of-fit is determined based on the average measured concentrations. In this study a Markov chain Monte Carlo technique will be used in conjunction with a food-web bioaccumulation model of hydrophobic organic contaminants (HOCs). Organism lipid fractions are important in the study of HOC bioaccumulation, yet there is relatively little data published with respect to these input parameters in aquatic organisms. This project investigates the impact that lipid fraction variability has on the bioaccumulation of HOCs in an aquatic food web. A spotted gar food-web bioaccumulation model will be used to demonstrate this approach. In support of the modeling effort, data will be gathered on lipid fractions in crayfish and concentrations of several polycyclic aromatic hydrocarbons in sediment, water and crayfish tissue. Field sampling and sample analysis will involve collaborations between researchers at Xavier University and Tulane University. Successful completion of this project will contribute to the scientific knowledge base on the naturally occurring variability in crayfish lipid fractions. Future studies of contaminant bioacumulation will benefit by being able to include prior knowledge of input parameter variability in estimates of organism concentrations. Broader impacts include development of an active collaboration between Tulane and Xavier researchers through which the participation of members from underrepresented groups in science and engineering can be increased, improved understanding of the biological fate of HOCs in crayfish and its dependence on organism lipid fraction and improved methods for estimation of ecological risk, thereby providing a stronger foundation for environmental decision making. ***