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Study Finds Elevated PBDEs in California

By Eddy Ball
November 2008

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Lead author Ami Zota
Lead author Ami Zota (Photo courtesy of Ami Zota)

Investigators funded by an NIEHS Environmental Justice Program grant report high levels of polybrominated diphenyl ethers (PBDEs), ubiquitous compounds used as a fire retardant in furniture, in the house dust and serum of people living in California. Serum levels of the compound penta-BDE in residents of California were twice the national average. House dust levels in California ranged from 4 to 10 times levels found in homes in other parts of the United States - and 200 times levels reported in Germany.

Published online October 1 by Environmental Science and Technology, the study was a collaboration involving researchers at the Silent Spring Institute ( NIEHS, the University of California Berkeley, Brown University and Communities for a Better Environment, a California-based environmental justice group. In addition to NIEHS financial support, which is overseen by NIEHS Program Analyst Liam O'Fallon, the study also received funding from the New York Community Trust.

Animal studies have demonstrated that PBDEs are associated with thyroid hormone disruption and adverse reproductive and neurodevelopmental effects. According to an Environmental Protection Agency review published earlier this year, the primary route of exposure is incidental ingestion and dermal contact with house dust, which raises special concerns about exposures in infants and toddlers.

Although PBDEs have been banned by the European Union and 11 states in the U.S. - and U.S. manufacturers discontinued production of PBDEs in 2004 - the scientists maintain that a substantial exposure reservoir remains in the environment. Older furniture continues to be an important source of exposure, and imported furniture containing PBDEs is still sold in many states. California's levels may be higher, the authors of the study speculate, because of the state's stringent furniture flammability standards adopted more than 30 years ago and the potentially harmful substitutes for PBDEs now in use or proposed.

"Virtually all the penta-BDE produced globally was used to meet this [California] fire standard," explained lead author and Silent Spring Postdoctoral Research Fellow Ami Zota, ScD, "and now these chemicals have been detected in nearly every species across the globe."

The study, led by scientists from the Silent Spring Institute, compared the concentrations in dust collected in 49 California homes with concentrations in dust collected under the same protocol from 120 homes in Massachusetts. The researchers also compared concentrations in their studies to reports by other investigators. The study used data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES) to compare serum levels of PBDEs in residents of California with those in participants living elsewhere in the U.S.

Although the study's authors acknowledged several limitations to the study, they argued that the ubiquity and persistence of the PDBE exposure reservoir should be a lesson for regulators. "These findings suggest the need for more anticipatory assessments of the environmental health impacts of consumer product decisions [about other untested flame retardants] prior to their implementation," they concluded.

The researchers also called on NHANES to reinstate its earlier practice of measuring thyroid hormone so that direct correlations between PBDE and thyroid can be made for humans participating in that large-scale annual survey.

Citation: Zota AR, Rudel RA, Morello-Frosch RA, Brody JG. ( Exit NIEHS 2008. Elevated house dust and serum concentrations of PBDEs in California: Unintended consequences of furniture flammability standards? Environ Sci Technol [Epub ahead of print] doi: 10.1021/es801792z

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