Toxic chemicals once used in flame retardants have been measured at the highest levels ever recorded in pregnant women, according to a study published by researchers from the University of California, San Francisco, Wednesday. The women are from Northern and Central California.
The chemicals are associated with lower IQs and attention deficit disorders in children. “Exposure to flame retardants that occur during early life can have long-lasting effects on the way that the fetal brain develops,” said Dr. Ami Zota with the UCSF Program on Reproductive Health and the Environment. Zota co-authored the study in the journal Environmental Science and Technology.
The scientists found polybrominated diphenyl ethers, also known as PBDEs, at unprecedented levels in 25 women in the second trimesters of their pregnancies. PBDEs have been banned in California since 2004.
Before 2004, the chemicals were commonly used in flame retardants to treat the polyurethane foam found in couches, chairs, and other household products, including baby products. Since the 1970s, California has required upholstered furniture that uses such foam to meet strict flammability requirements.
But the PBDEs were not chemically bound to the foam; as a result, they scattered throughout indoor environments, where they could be inhaled through dust. Because furniture is typically used for many years and the chemicals don't quickly degrade, PBDEs are still present throughout the state.
“Californians, just by living and doing what they normally do, have exposures that are two to five times higher than other U.S. populations and 10 to 100 times higher than populations in Asia and Europe,” Zota said.
PBDEs are among 23 chemicals banned under the Stockholm Convention on Persistent Organic Pollutants, a United Nations treaty, which more than 150 countries, but not the U.S., have signed.
The UCSF study, though small, found an association between the elevated PBDE levels and thyroid hormone disruption. In adults, thyroid hormones regulate metabolism, but in fetuses and young children, they play a key role in brain development.
During the first 12 weeks of pregnancy, fetuses haven’t yet begun to make their own thyroid hormones, making them dependent on their mother’s hormones.
Thyroid disruption during fetal development can lead to reduced IQ, attention deficit disorders and sensory processing problems, Zota said. It can also increase the risk of pregnancy complications.
Women who develop thyroid problems during pregnancy are at increased risk for thyroid and cardiovascular disease later in the life.
“There have been many hundreds of animal studies showing that these flame retardants that are at high levels in our furniture and baby products cause thyroid, endocrine, reproductive and neurological problems,” said Arlene Blum, a visiting scholar in chemistry at University of California, Berkeley, and executive director of the Green Science Policy Institute. “It’s sad but not surprising that we’re seeing the same effects in humans.”
In recent years, state Sen. Mark Leno has introduced legislation to eliminate or change the flammability standard, but the Legislature has repeatedly rejected the bills.
The 25 women in the UCSF study were low-income, which may put them at increased risk of exposure. “When you look at a population of people who have limited incomes, they probably aren’t buying a new couch every year,” said Dr. Sarah Janssen, a senior scientist for the Natural Resources Defense Council. Exposures from furniture may be greater if the fabric or foam gets old and deteriorates.
There are steps families can take to minimize their exposure to toxic chemicals at home, but some, like buying special air filters, are expensive. The cheapest thing to do is to wash your hands frequently so you don't ingest dust when you eat. For more information on how to protect yourself, click here.