Researchers find big drop in flame retardant levels in women
09/29/2013 12:00 AM
09/28/2013 11:21 PM
The rate of flame retardant chemicals in the blood of pregnant women has dropped precipitously between 2008 and 2011, a new study reveals.
University of California, San Francisco, researchers found a 65 percent decline in the average levels of polybrominated diphenyl ethers, or PBDEs, in pregnant women’s bloodstreams between 2008 and 2011 – and is the first such study to show a drop in PBDEs in California women tested for the chemicals. In 2008, the Environmental Science & Technology journal reported that Californians had double the amount of toxic flame retardants in their blood as the national average.
The UCSF study is part of a statewide chemical biomonitoring effort. Flame-retardant chemicals in the bodies of Californians also are being studied in the Central Valley in a joint effort between researchers at UC Berkeley and Kaiser Permanente. In that study, researchers seek to measure flame retardant levels in 300 men, women and children. That study is one-third complete, and its results have yet to be published.
In the UCSF study, 25 women in 2008-09 and 36 women in 2011-12 were studied. Nearly half of the women hailed from the Central Valley. All women were in the second trimesters of their pregnancy and were tested at a clinic at San Francisco General Hospital. All of the women were there to terminate a pregnancy.
All women tested from in 2008-09 had five different categories of PBDEs measured in their her blood. By 2011-2012, only one of the five PBDEs was present in every woman tested.
The presence of those chemicals stems from the state seeking to do a public good in 1970, when it mandated the use of flame-retardant chemicals in the manufacture of furniture and other products.
As a result, a slew of flame-retardant chemicals began appearing in polyurethane foam inserted inside couches and love seats, and in carpeting sold in the state. Not long after that, high levels of PBDEs were found in California women.
Myrto Petreas, who co-authored the research paper and is chief of environmental chemistry at the state Department of Toxic Substance Control, said the decline might be the result of the statewide ban on PBDEs that began in 2004, and a voluntary national phaseout that followed.
The statewide ban itself might not be the reason PBDE rates declined in the study. PBDE is considered a persistent legacy chemical, especially in homes. It is assumed that furniture foam treated with the flame retardant does not get replaced frequently. Because of that fact, Petreas finds the decline puzzling.
“I was surprised with the drop. I had expected that it would have taken much longer,” Patreas said. “We all tend to keep our furniture – so we’re wondering what has changed.
“Other chemicals, like pesticides and dioxins – these are only found in what you eat. Most of us eat the same things, so we all have similar levels of those. But with PBDEs, some people have seriously high levels, and we can’t explain why.”
Petreas sees the decline as the latest example of how successful biomonitoring of chemicals has become in California. The state’s biomonitoring program began in 2006 and is focused on measuring the presence of chemicals in the human body and tracking changes in those levels in the state’s population. That information, in turn, has been used to inform public health policy.
“The drop in PBDEs shows that if something is restricted or banned, it does have an effect,” Petreas said. “And it shows the power and the importance of biomonitoring to demonstrate how those levels change over time.”
One of the UCSF study’s authors, Tracy Woodruff, believes it is only through biomonitoring that it can be established what chemical phaseouts accomplish in a population. She likens the current biomonitoring of flame-retardant chemicals to the phasing out of leaded gasoline in 1983. After that, the Centers for Disease Control and Prevention reported a steep drop in the levels of lead in in the blood of Americans between 1976 and 1980.
“One of the things that is so amazing about the UCSF study is that we’re seeing the same type of relationship where we ban a certain class of flame retardant and when we measure them – not to look at the effect of the regulation – we see this side effect,” Woodruff said.
The phaseout of PBDEs in California also has created a situation in which new flame-retardant chemicals are being used in foam products in furniture and carpeting. Some of those new chemicals have the potential of being just as troublesome and persistent as the banned flame retardants, said Ami Zota, lead researcher of the UCSF study and assistant professor at the George Washington University School of Public Health.
One of the newer flame retardants is known as Firemaster 550 and has not been widely studied. The chemical is one of the more popular replacements for phased-out PBDE chemicals.
A recent study at Duke University found that Firemaster 550 acts as an endocrine disruptor and weight-gain trigger in laboratory rats. That study was the first to establish that Firemaster 550 component chemicals had effects on lab animals.
“Scientists are concerned that these chemicals are starting to show up when we do not know what their potential for adverse health effects will be on the population,” Zota said.
She believes that the flame retardants in general do not protect the public good in the ways intended, since they do not prevent fires. The retardants’ presence in California stem from the state’s flammability standard – named Technical Bulletin 117 (TB 117) – which mandates that foam furniture withstand a 12-second exposure to a small open flame.
That standard is under review because of the evidence pointing to the problems with flame-retardant chemicals – which include neurological development issues in children.
An alternative to TB 117 involves doing away with the 12-second open-flame test in favor of a “smolder-only” test. That standard would be much easier for manufacturers to meet and would not require the addition of flame-retardant chemicals. The chemical industry is opposed to revising TB 117.
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