Schecter, A, M Pavuk, O Päpke, JJ Ryan, L Birnbaum and R Rosen 2003. Polybrominated diphenyl ethers (PBDEs) in U.S. mothers’ milk. Environmental Health Perspectives doi:10.1289/ehp.6466 (available at http://dx.doi.org/).

Background on PBDEs

Schecter et al. report they find comparatively high levels of PBDEs in breast milk from mothers in Texas. The levels measured are comparable to those found by other recent US studies in breast fat and maternal and cord serum. They are up to 100 times higher than recent measurements of PBDEs in European breast milk.

While a definitive answer for the high levels in the US compared to Europe awaits further systematic study, it most likely relates to differences in the use of brominated flame retardants in various consumer products, combined with recent European moves to decrease exposures.

Policy makers have recently begun to consider reductions in PBDE exposures in the US. As of August 2003, only the State of California has taken concrete steps.

What did they do? Schecter et al. obtained breast milk from volunteers at two health centers in Texas (Austin and Dallas). Samples were then shipped to two World Health Organization-certified laboratories in Canada and Germany for analysis of PBDE levels. In all, measurements of 13 different PBDE congeners were obtained from 47 individuals, few if any of whom were exposed occupationally.

What did they find? This first-ever study of PBDE levels in American's breast milk finds extremely elevated levels of PBDEs compared to European levels.

As seen in the graph to the right, the 10 women (21% of those sampled) had PBDE concentrations above 100 ppb, with the highest milk level at 419 ppb. Fifteen women (32% of sample) had levels over 50 ppb. The scientists found no relationship between PBDE levels and the age of the woman measured, nor did they observe any racial differences in PBDE concentrations.

As shown in the graph to the left, the Texas measurements made by Schecter et al. were dramatically higher than those reported in recent studies from Europe, and somewhat higher than recent data from Canada. Levels in Canada appear to have risen over the past decade. Graphs adapted from Schecter et al.

What does it mean? This study of 47 Texas women adds to the growing body of scientific evidence demonstrating high levels of PBDEs in Americans at levels 10 to 100 times that seen in Europe. It is the first study undertaken of PBDEs in breast milk in the US.

The sources of exposure responsible for these high PBDE body burdens are uncertain. PBDEs are widely used in a variety of consumer products and can be found in food, household dust and sewage sludge, among many places. Swedish levels appear to be declining following implentation of a ban. Coincidentally, the week that Schecter et al.'s study appeared online (8 August 2003), California's Governor signed a law banning some PBDEs in California.

The main concern about PBDEs is their ability to disrupt thryoid function, and thus interfere with proper brain development, at least as indicated by experiments with laboratory animals and cells in culture. No published epidemiological studies have examined the impact of PBDEs on people. Yet over the same time period that PBDE body burdens have been increasing dramatically Americans, we have also witnessed apparent increases in the frequency of a number of neurobehavioral abnormalities in people, including autism and attention deficit hyperactivity disorder. Surely this coincidence warrants investigation.