PBDEs

PBDEs, or polybrominated diphenyl ethers, are a class of brominated flame retardants used to reduce the flammability of plastics, foams, textiles, and electronic equipment. They consist of two phenyl rings connected by an ether linkage, with varying numbers and patterns of bromine substitutions. Commercial formulations include penta-, octa-, and deca-BDE, among other mixtures. PBDEs are highly persistent in the environment and are lipophilic, tending to accumulate in fatty tissues of wildlife and humans. They can be transported long distances and have been detected in air, dust, sediments, wildlife, and human blood and breast milk.

Exposure occurs mainly through ingestion of contaminated food, inhalation of indoor dust, and, for infants, via breast milk. Health concerns include potential neurodevelopmental effects in children, endocrine disruption, and thyroid hormone disruption, though findings vary by congener and exposure level. Risk assessments reflect ongoing uncertainty and the need to consider mixture effects.

Due to persistence and bioaccumulation, many PBDEs have been subject to regulatory action. Penta- and octa-BDE mixtures have been phased out or banned in several regions, and deca-BDE has been restricted or limited in use in some jurisdictions. The Stockholm Convention on Persistent Organic Pollutants has addressed certain PBDE congeners with controls and monitoring. As a result, industry has shifted toward alternative flame retardants, including non-halogenated or phosphorus-based compounds, though comprehensive assessments of alternatives are ongoing.

Analytical and environmental research continues to track trends in PBDE levels in humans and wildlife and to understand transformation products formed through degradation.