Another Flame Retardant Found in Household Dust
[Rachel's Introduction: More than a million pounds of Dechlorane Plus are released into products each year. The chemical's structure is similar to that of organochlorine pesticides such as heptachlor, chlordane, aldrin, and mirex, all of which have been either banned or restricted in the U.S. Now it has been found in household dust.]
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By Kellyn Betts

Researchers in Canada have found that the flame retardant Dechlorane Plus accumulates in residential dust.

New research published in ES&T (DOI: 10.1021/es071716y) documents for the first time that a persistent and bioaccumulative flame retardant known as Dechlorane Plus can be found in household dust.

Jiping Zhu of Health Canada and his colleagues say their research suggests that more information is needed on the compound's toxicity, how it degrades in the environment, and whether it is present in people.

Dechlorane Plus is manufactured by OxyChem, and the U.S. EPA lists it as a high-production-volume compound, a designation for compounds manufactured in volumes of more than 1 million pounds annually. The chemical's structure is similar to that of organochlorine pesticides such as heptachlor, chlordane, aldrin, and mirex, all of which have been either banned or restricted in the U.S.

Very few data are publicly available on Dechlorane Plus's toxicity. At the behest of EPA, OxyChem is currently conducting toxicology tests to collect more information about the compound's environmental, reproductive, and developmental effects. "Based on all the information we have seen, we believe that Dechlorane Plus is a safe and effective product," says Richard S. Kline, the company's vice president of communications and public affairs.

Dechlorane Plus is not included on Environment Canada's priority list because quantitative structure-activity relationship data indicate that the compound is not likely to be very bioaccumulative, says Derek Muir, a senior research scientist with Environment Canada. However, the first evidence that Dechlorane Plus persists in the environment and can bioaccumulate in fish was published in 2006 (Environ. Sci. Technol. 2006, 40 (4), 1184-1189). More research is needed to investigate whether the compound biomagnifies in aquatic and terrestrial food webs, Muir says.

Zhu credits the 2006 paper with inspiring his team to look for the compound in household dust. He and his colleagues began by analyzing 69 archived samples collected in 2002 and 2003 from homes in Ottawa. They confirmed that Dechlorane Plus continues to be present in dust by testing additional samples collected this year.

The data suggest that unlike the levels of the compound in the outdoor environment, which have been decreasing since the 1980s, the levels in indoor environments do not appear to be declining, points out Tom Harner, a research scientist with Environment Canada.

In addition, the 2003 sample set included one outlier harboring Dechlorane Plus concentrations 2 orders of magnitude greater than the median. This is significant, the authors emphasize, because children can take up much higher concentrations of compounds from dust per unit of body weight than adults.

Dechlorane Plus is used primarily in cables and wires, according to Kline. Zhu and his colleagues say that they were unable to determine the source of the compound in any of the tested samples.

"It is unclear what the health implications are, due to poor toxicology data, but that in some ways increases the concern. How many more of these kinds of things are we going to find and then spend years or decades investigating?" asks Tom Webster of the Boston University School of Public Health's department of environmental health, whose group investigates exposure to flame retardants in dust. "That may be a good employment scenario for environmental scientists but sounds like bad policy to me."

Copyright 2007 American Chemical Society