Papers published in the journal, Environmental Science & Technology, 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, which humans can inhale.

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 household 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: “Many people have assumed that volatilization is the main process responsible for flame retardants escaping into indoor environments. ” Now researchers have taken a new approach by trying to pinpoint where the bromine is actually located in the dust. Taken together, these papers represent a significant step forward for researchers interested in how people and animals take up flame retardants.

Webster and his team analyzed house and automobile dust samples with extremely high levels of BDE-209, the main component of a flame retardant mixture widely used in TVs and other electronics sold in the U. S. The second study analyzed dust samples from a wider array of sources, including hotels, restaurants, hospitals, and day care centers. Both groups observed many bromine-rich fragments that were unevenly distributed within the dust samples

When the concentrations of PBDEs in some of the fragments were analyzed, it was discovered that the particles also contained bromine from additional sources. This suggests the presence of other brominated retardants. Wear and tear can easily explain how automotive upholstery and curtains fragment; why plastic breaks down is less obvious. An authority on dust explains it this way: “Plastics... tend to degrade just by drying out. ” Changes in atmospheric humidity will also cause plastic[s] to deteriorate, with different plastics having different rates of decay.

These two papers suggest that people can be exposed to very high concentrations of brominated flame retardants via plastic and fibre fragments. The new findings merit further study because people’s ability to bioaccumulate PBDE retardants has been amply documented. Animal research has linked PBDEs to a number of health effects and has shown that deca-BDE is readily bioavailable in dust.

Betts, K. CSI-style tools offer clues about flame retardants in dust. Environ. Sci. Technol. (web), March 18, 2009
Suzuki, G et al. Existence State of Bromine as an Indicator of the Source of Brominated Flame Retardants in Indoor Dust, Environ. Sci. Technol., 2009, 43 (5), pp 1437–1442