Two new papers published in ES&T provide the first evidence that computers, TVs, and other electronic products, as well as textiles, can slowly degrade over time to produce tiny plastic fragments containing relatively high concentrations of bromine. The work is significant because it sheds light on the mystery of how brominated flame retardants get into indoor dust, where humans can be exposed to them.
Over the past few years, scientists have amassed data confirming that the brominated flame retardants used in plastic and fabric consumer goods are found in the air and dust in people’s homes, workplaces, and automobiles. At least seven retardants have been documented in indoor air and dust from North America, Europe, and Asia. Researchers have definitively linked the levels of one widely used class of retardants, PBDEs, in homes’ dust with PBDE concentrations found in the residents’ breast milk.
Until now, however, no one has been able to explain exactly how the retardants migrate out of the products they are intended to protect and into the dust, says Tom Webster of Boston University’s School of Public Health, lead author of one new ES&T paper (DOI 10.1021/es803139w). “Many people have assumed that volatilization is the main process” responsible for flame retardants escaping into indoor environments, Webster says.
In their work, Webster and Go Suzuki of Ehime University’s Center for Marine Environmental Studies (Japan) and colleagues take a new approach by trying to pinpoint where the bromine is actually located in the dust, says Cynthia de Wit of Stockholm University’s Department of Applied Environmental Science. Taken together, the papers represent “a significant step forward“ for researchers interested in how peopleand animalstake up flame retardants, she says.
Webster and his team jokingly call this their CSI paper, in reference to the popular American television show, CSI: Crime Scene Investigation, because they used some of the investigative tools found in police laboratories. Using scanning electron microscopy, Fourier transform infrared microspectrophotometry, and energy-dispersive X-ray analysis, they analyzed house and automobile dust samples with extremely high levels of BDE-209 (260−2600 micrograms per gram of dust) from the U.S. and the U.K. BDE-209 is the main component of the deca-BDE flame retardant mixture, a PBDE formulation widely used in TVs and other electronics sold in the U.S. BDE-209 was ideal for this research because it is highly nonvolatile, Webster says.
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