Digestive Solubilization of Sediment-Sorbed Contaminants: A Comparison of In Vitro and In Vivo ProcessesEPA Grant Number: R825353
Title: Digestive Solubilization of Sediment-Sorbed Contaminants: A Comparison of In Vitro and In Vivo Processes
Investigators: Weston, Donald P. , Mayer, Larry M. , Penry, Deborah L.
Institution: University of California - Berkeley , University of Maine
EPA Project Officer: Hahn, Intaek
Project Period: December 1, 1996 through November 30, 1999
Project Amount: $374,945
RFA: Exploratory Research - Environmental Biology (1996) RFA Text | Recipients Lists
Research Category: Biology/Life Sciences , Ecosystems
Description:The goal of the proposed work is to confirm and expand upon early work, and contrast in vitro digestive fluid solubilization with in vivo digestive processes, bioavailability and bioaccumulation. The in vitro technique allows the researchers to answer mechanistic questions by manipulating sediment or digestive fluid characteristics in ways that would not be possible in vivo, but first there is a need to establish that in vitro solubilization provides meaningful information in the context of the whole animal's accumulation of sediment-sorbed contaminants. Included within this objective are contrasts between the novel digestive fluid solubilization approach and more traditional means of measuring bioavailability such as absorption (assimilation) efficiency, uptake clearance rates and steady state body burdens. The researchers then intend to expand the research to examine its generality to multiple species and varied substrate types.
As in vitro digestive fluid solubilization is investigated, the researchers would like to use the technique to better understand the mechanisms of bioaccumulation of contaminants from ingested sediments. They are interested in the properties of digestive fluid that promote solubilization of contaminants. They hope to understand why, when incubated with digestive fluid, some sediments desorb far more contaminants than others. They intend to establish for which contaminants digestive processes are important to bioaccumulation, and for which uptake from the dissolved aqueous phase predominates. The researchers would ultimately like to incorporate digestive absorption into their approach, which currently emphasizes only solubilization in digestive fluid. Finally, they hope to establish the relationship between the fraction of contaminant bioavailable to that organism and the fraction solubilized by digestive fluid.
The researchers are developing digestive fluid solubilization as a tool to better understand the processes of bioavailability and bioaccumulation of sediment-sorbed contaminants. Virtually any environmental assessment effort in which there is a need to manage contaminated sediments, and for which assessing bioavailability is critical, could ultimately benefit if we are able to better understand the processes that makes sediment-associated contaminants bioavailable.