The Basics of Polybrominated Diphenyl Ethers (PBDEs)

Adapted from Manchester-Neesvig et al. 2001. Environmental Science and Technology 35:1072-1077

Some PBDE pages at www.ProtectingOurHealth.org:
Single low-dose of PBDE causes ADHD and low sperm count
PBDEs shown to be developmental neurotoxicants in mice
BDE-99 disrupts brain growth spurt in mice
PBDE levels increasing rapidly
High PBDE levels in California and Indiana
PBDEs are potent thyroid disruptors

Recent press about PBDEs.
For much more click here

 

PBDEs are added to materials to decrease the likelihood and intensity of fire in a wide variety of products, including vehicles, furniture, textiles, carpets, building materials, electronic circuit boards and cases... just about anywhere that plastics are used.

Some of the most common plastics to which PBDEs are added are high-impact polystyrene, polyurethane foam, wire and cable insulation, and electrical and electronic connectors. PBDEs can constitute quite a large percentage of the final product... up to 30%.

PBDEs work because they decompose at high temperature and liberate bromine atoms, which are effective at slowing and stopping the basic chemical reactions that drive oxygen-dependent fires.

PBDEs are mixed with polymers as plastics are being made. Because they do not bind chemically with the plastic, they leach continuously out of the final product. Thus given the ubiquity of plastic in the modern world, it is not surprising that PBDEs are being found in the environment.

 

 
graph from NRDC		  
  PBDEs now contaminate human milk. Swedish research reveals that contamination levels in breast milk have increased more than 50-fold over the period 1972 to 1997 (Meironyté et al. 1998). PBDEs are also found in human fatty tissue and in human blood serum.  

Roughly 50,000 metric tons of PBDEs are produced annually world-wide, with 40% of their use in North America.

Because PBDEs are both lipophilic (they concentrate in lipids, or fats) and extremely resistent to physical, chemical or biological degradation, they are highly persistent and bioaccumulative... classic POPs although not yet included in the Stockholm Convention on Persistent Organic Pollutants.

PBDEs are chemical similarity to dioxins and PCBs, although far less studied from a toxicological perspective. What is clear is that they are potent thyroid disruptors, 7x more powerful than human thyroxine at binding with human transthyretin.