Proceedings 2008/012

Review of Potential Impacts of Polybrominated Diphenyl Ethers (PBDEs) in the Aquatic Environment; January 24, 2008

Chairperson: Wayne Fairchild

Summary

On January 24th, 2008 a video conference/teleconference workshop was convened with the purpose of reviewing the research done by DFO on the potential impacts of polybrominated diphenyl ether (PBDE) flame retardants in the aquatic environment. PBDEs are flame retardant chemicals used widely in consumer products such as computers, electronics, automobiles, and textiles. DFO research has reported that PBDE concentrations are increasing rapidly in the aquatic environment, with levels in fish and seals doubling every 3.5 years. The scientific literature reports data that demonstrates that PBDEs are ‘persistent, bioaccumulative and toxic at high concentrations’ in aquatic organisms. A lack of information on aspects of their bioaccumulation and toxicity to various (aquatic) organisms has impaired the ability of risk assessors to evaluate the risks of PBDEs. Environment Canada is presently drafting regulations on the three types of PBDE technical formulations, namely pentaBDE, octaBDE and decaBDE. During the teleconference review, participants conducted a scientific review of the paper. While lack of cause-and-effect evidence for PBDE impacts at the population level was cited as problematic by some reviewers, other participants thought that it would be impossible to show a definitive mechanistic link, given the complex contaminant mixtures found in the environment. However, there was general agreement that more ecotoxicological data are required to accurately assess the risk posed by PBDEs in the aquatic environment.

A ‘weight of evidence’ supports that PBDEs are persistent, bioaccumlative and toxic contaminants at high concentrations, and may pose a risk to aquatic food webs in Canada (i.e., the possibility of harm), and that the situation is worrisome given that recent studies have shown rapidly escalating concentrations in several Canadian aquatic and aquatic-related species. Certainty in this regard would be increased by additional data linking PBDEs at realistic environmental concentrations to adverse effects to fish, and marine mammals and birds and their prey.

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