Polybrominated diphenyl ethers in an advanced wastewater treatment plant. Part 2: Potential effects on a unique aquatic system

Concentrations of the mono- through deca-substituted polybrominated diphenyl ether (PBDE) flame retardants were determined in the aqueous effluent from a tertiary-level wastewater treatment plant (WWTP) that uses post-filtration ultraviolet light disinfection. The WWTP is located in a semi-arid region of British Columbia. Subsequent limnological modeling of receiving waters examined the potential long-term effects of various PBDE-loading scenarios on this unique aquatic system. Over the three decades from 2002 to 2031, total PBDE concentrations in the water column and in suspended and surficial sediments are expected to increase to >120 pg·L^–1 and ~1 ng·g^–1 wet weight, respectively. Following implementation of a hypothetic halt on PBDE releases into the aquatic system, individual PBDE congener concentrations in the water column and sediments declined by <35% over the ensuing 17-year modeling period after the ban, illustrating the potential long-term problem arising from continued PBDE inputs into aquatic systems worldwide. The results also suggest that PBDEs represent one of the single largest halogenated aromatic loadings to Canadian lakes, rivers, and streams from wastewaters, and their worldwide use continues to increase exponentially. Key words: polybrominated diphenyl ethers (PBDEs), flame retardants, municipal wastewater treatment effluent, contaminant fluxes, limnologic modeling.