Whenever I write about toxic flame retardants known as polybrominated diphenyl ethers, or PBDEs, I become more convinced that we have a problem, mainly because these chemicals do not tend to break down in the environment.
Evidence indicates they are being washed into streams and tend to accumulate throughout the food web, although the trend may be slowing or even declining in Washington state, which has banned most forms of PBDEs. (Review the Water Ways entry from April 2, with links to other information sources.)
OK, so they’re a concern. But are they really harmful?
Ongoing studies have linked the chemicals to neurological and developmental problems in mice and rats, which could have implications for humans as well as other mammals.
But an important new laboratory study, by researchers with the Canadian Wildlife Service, may be the first to link the chemical to reproductive problems in birds — and at concentrations actually found in the environment.
The researchers reported that the chemicals caused thinner egg shells for American kestrels, a predatory bird that has been declining in numbers in the eastern U.S. and Canada. Furthermore, egg laying was delayed for females fed the chemicals versus those that did not get it.
The levels that caused reduced egg viability have been found not only in wild kestrels but in herring gulls and peregrine falcons as well. I would think this would be a concern for all our predatory birds, if not other species as well.
Karen Kidd and Wendy Hessler discuss these findings in the latest issue of Environmental Health News. Guess what the magazine titled their article: “Are flame retardants the next DDT?”
That refers, of course, to the chemical Dichloro-Diphenyl-Trichloroethan. Before it was banned, DDT became linked to thinning eggshells in eagle nests. DDT failed to break down readily in the environment, contaminating the entire food chain and playing a major role in the creation of the Endangered Species Act.
