SEMIPERMEABLE-MEMBRANE DEVICES CONTAINING MODEL LIPID - A NEW APPROACH TO MONITORING THE BIOAVAILABILITY OF LIPOPHILIC CONTAMINANTS AND ESTIMATING THEIR BIOCONCENTRATION POTENTIAL

Low density "layflat" polyethylene tubing containing thin films of model lipid may simulate the bioconcentration of nonpolar organic contaminants by aquatic organisms. These semipermeable polymeric membrane devices (SPMDs) are shown to hold considerable promise as time-integrated concentrators of nonpolar organics in aquatic environments, and as a method for estimating bioavailability and potential bioconcentration factors for contaminants in organisms. The devices may also help define the relative role of equilibrium partitioning in the bioaccumulation of organic contaminants. The use of purified lipid extracts from aquatic organisms or specific lipids, such as triolein, in SPMDs is made more practical by a complementary analytical development showing the utility of polyethylene film as a membrane for dialyzing nonpolar organic compounds from coextracted lipids. Data are presented on the uptake kinetics and steady state distribution coefficients of aqueous residues of fenvalerate, mirex, 2,2′,5,5′-, and 3,3′,4,4′-tetrachlorobiphenyls when lipids are used in SPMDs. The feasibility of the SPMD approach for in situ monitoring of environmental contaminants is demonstrated by exposing SPMDs to AsanaR (an isomer of fenvalerate) in a littoral enclosure of a small pond. © 1990.