SHANGHAI – Scientists at the East China University here say printed circuit boards in landfills and electronic waste recycling sites are a “significant emission source” of brominated flame retardants (BFRs).

The scientists studied the leaching of five heavy metals and two BFRs from waste PCBs. Copper and lead were the most “leachable” heavy metals, and penta-bromodiphenyl ether (penta-BDE) was prevalent in the extracts.

High levels of dissolved organic matter were said to raise the leaching rates of the flame retardants.