Environmental Science
Third Runner-up: On the trail of hidden dangers
“Hexabromocyclododecanes (HBCDs) in the Environment and Humans: A Review” by Adrian Covaci and Stefan Voorspoels, University of Antwerp; Andreas C. Gerecke, Martin Kohler, and Norbert V. Heeb, Swiss Federal Laboratories for Materials Testing and Research (Empa); Robin J. Law and Collin R. Allchin, Centre for Environment, Fisheries and Aquaculture Science (U.K.); and Heather Leslie and Jacob de Boer, Netherlands Institute for Fisheries Research, 2006, 40 (12), 3679–3688.
Adrian Covaci and colleagues knew that ES&T wanted all the juicy details—the story behind the story—when their article was chosen as one of ES&T’s top papers. In a deft maneuver to elude hungry reporters, coauthor Andreas Gerecke claimed, “It was just ordinary research.”
The facts tell a different story.
Led by Covaci at the University of Antwerp (Belgium), an international team of scientists has been studying hexabromocyclododecanes (HBCDs), a group of brominated flame retardants widely used in Europe and common in such hidden places as building insulation, electrical housings, and polystyrene foams. Their ES&T paper turned the spotlight on these lesser-known cousins of polybrominated diphenyl ethers (PBDEs) that may cause similar health and environmental problems.
Gerecke says that reviewing the literature was like much of the usual labor of science—painstaking and filled with “endless Excel sheets”—but in the end, he adds, this hard work revealed some surprises.
The team pulled together research from across the life span of HBCDs, following their trail from chemical makeup to environmental release, then tracking their whereabouts in wildlife and humans, and finally investigating their modus operandi.
Covaci, originally from Romania, began studying HBCDs in 2000 after coming to Belgium for doctoral studies. At the time, only a few research groups were examining the compounds. That seeming lack of interest was not by chance; with 16 possible isomers, the contaminants are notoriously difficult to analyze. Another Swiss member of the team, Norbert Heeb of EMPA, made such research more feasible by developing an analytical technique that used liquid chromatography/mass spectrometry.
In different corners of Europe, researchers started piecing together bits of a puzzle over the last decade. Gerecke, Heeb, and Martin Kohler studied the stereochemistry of HBCDs. Robin Law, Collin Allchin, Heather Leslie, and Jacob de Boer traced the chemicals through food webs, and data started streaming in from other labs. Meanwhile, Covaci and Stefan Voorspoels published results in ES&T showing that the compounds behaved much like PBDEs in fish tissues. ES&T highlighted the topic in a feature article later that year.
In response to the feature story, the Hexabromocyclododecane Industry Working Group, which is composed of HBCD producers and users, wrote a letter to ES&T. The group took issue with the characterization of HBCDs as persistent organic pollutants (POPs) and said that the available scientific literature did not support that conclusion.
The letter helped spur Covaci and many of the feature article’s authors to write the review, which they say was needed to clarify and compile what is known about HBCDs. “We wanted to stress in this review that HBCDs are POPs-like compounds; they’re toxic, they accumulate, they’re persistent, and they undergo long-range transport,” Covaci says.
Covaci says he also hoped to inform the European risk assessment for HBCDs, which has been ongoing since 1997. “I had thought that maybe having a review would give it a boost,” he says. Although the assessment is still not complete, Covaci doesn’t seem discouraged. No matter what, he says, “we still have a lot to clarify and learn.”
