Reconstructing source polybrominated diphenyl ether congener patterns from semipermeable membrane devices in the...

Semipermeable membrane devices (SPMDs) were placed in the Fraser River near Vancouver, British Columbia, Canada, between August 6 and September 30, 1996. This location is near a large urban and industrial region (population 2,000,000) and is expected to be representative of other large, modern cities. After exposure to the ambient water column, SPMD samples were analyzed for a suite of 36 polybrominated diphenyl ether (PBDE) congeners plus all homologue groups from mono- through hexa-brominated. Observed congener patterns differed significantly from that of the commercial penta- and octa-BDE mixtures. A reconstruction approach was developed based on an aquatic transport model and utilizing published octanol-water partition coefficients, calculated SPMD uptake rates, and predicted water concentrations by using the EcoFate multimedia mass balance aquatic simulation model for the 13 major PBDE congeners. In combination, composite technical mixtures were created by combining commercial penta-BDE mixtures (Bromkal 70-SDE and Great Lakes Chemicals DE-71) with commercial octa-BDE mixtures (Bromkal 79-8DE and Great Lakes Chemicals DE-79) in their relative 2000 North American production volumes. The reconstructed SPMD patterns more closely approximated the composite technical mixtures and suggest that PBDEs in such an industrial region arise primarily from penta- and octa-BDE source mixtures.