A new state study suggests the amount of flame retardants found in the breast milk of Northern California women declined significantly over about a decade, possibly as a result of a 2003 state ban on the toxic chemicals.
The results announced Wednesday by the California Department of Toxic Substances Control found that the amount of polybrominated diphenyl ethers or PBDEs, found in the breast milk of one group of first-time mothers was 39 percent less than the amount found in a larger sample of previously studied first-time mothers.
Researchers examined 66 women recruited for observation at the Women’s Health and Birth Center in Santa Rosa between 2009 and 2012. The study compared the results to PBDE levels found in a group of 82 first-time mothers from a previous department study conducted in 24 California communities between 2003 and 2005.
A 2003 state bill banned the use of PBDEs in products sold in California, prompting a dozen other states to adopt their own bans. Until then, the chemical had been commonly used in clothing, carpeting and furniture foam.
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“This study shows that regulatory and public health intervention works,” said department director Barbara Lee. “The new findings underscore the importance of biomonitoring studies, and highlight the concrete benefits of product reformulation.”
Studies show exposure to PBDEs can impair hormonal function and the neural development of young children.
The chemicals were used in furniture foam after the state adopted a flammability standard in 1975 that required all foam and other products to withstand 12-second exposure to an open flame. California was the first state to adopt the standard, prompting furniture makers to use flame retardants in products sold nationwide.
Regulators later found that flame retardants were being released into the environment as household dust. Exposure to that dust, in turn, can lead to the retardants accumulating in people’s bodies.
PBDEs remain persistent in homes statewide, especially with the average lifetime of furniture stretching to 30 years. A 2008 study published in Environmental Science & Technology found that Californians had double the amount of toxic flame retardants in their blood compared to the national average.
A 2013 University of California, San Francisco, study found a 65 percent drop in the average levels of PBDEs in pregnant women's bloodstreams between 2008 and 2011.
Despite the declines, the newest study found that vulnerable populations, such as pregnant women and children, continue to be exposed to PBDEs. The study also found that, despite declining levels, all breastfed babies were exposed to PBDEs, with 30 percent of those exposed to high levels.