Contamination of the environment by commercial and industrial chemicals is an undesirable byproduct of modern society. A new group of pollutants that have emerged in recent years are the brominated flame retardants, and in particular the polybrominated diphenyl ethers (PBDEs). Our paper was one of the first to report significant, widespread environmental PBDE contamination in the U.S., namely the contamination of Lake Michigan salmonids. Lake Michigan salmonids have long been recognized as a sentinel for societal chemical contamination. As awareness and concern over PBDE contamination in the U.S. has grown, numerous papers on PBDEs have been published since publication of our paper. Many of these papers have referenced our work.

While PBDEs have been observed in environmental samples in Europe and Asia for a number of years, their presence in North America at high concentrations has only recently been recognized. Our work showed that PBDEs have reached the upper trophic levels of a major North American freshwater system. Our work also shows similarities between contamination of the environment by PBDEs and by PCBs, a more thoroughly researched environmental pollutant.

In the early 1990s colleagues at the Wisconsin Laboratory of Hygiene (Wisconsin's State Public Health Laboratory) began noticing chromatographic peaks in fish samples from the Great Lakes. Although tentatively identified as brominated compounds, their status could not be confirmed because analytical standards were not available for PBDEs. Through some fortuitous events, we became acquainted with Professor Åke Bergman at Stockholm University. Professor Bergman, a leader in the PBDE field in Europe, was synthesizing PBDE congeners for use as analytical standards in his own research. When Professor Bergman's doctoral student came to study in our laboratory at the University of Wisconsin-Madison for several months on an American Chemical Society fellowship, Professor Bergman sent some of his analytical standards with him. Armed with the proper standards, we began an organized study of the levels of PBDEs in Lake Michigan salmon. Because much past research at our laboratory has focused on the fate and transport of PCBs in the Great Lakes, it was natural to compare levels of PBDEs with PCBs.

  Could you summarize the significance of your paper in layman's terms?

Polybrominated Diphenyl Ethers are used as flame retardants in many commonly used materials such as polyurethane foam, plastics and textiles. PBDEs are mixed with, rather than bonded to, the materials they protect. Thus, PBDEs continually migrate from the protected material into the environment. PBDEs are now found in many environmental compartments, such as air, water and wastewater sludge. As use of brominated flame retardants continues, levels in the environment will likely become higher. Toxicological evidence is growing indicating that PBDEs can invoke toxic responses in many organisms. Consequently, our research shows that a new group of potentially toxic chemicals is moving beyond their intended use and into the environment, where their impact could be similar to that of PCBs if their use is unrestrained.