High levels of toxic PBDE found in pregnant California women
A study released Wednesday found the highest levels ever reported among pregnant women worldwide of toxic polybrominated diphenyl ethers (PBDEs), flame retardant chemicals largely banned in California in 2004.
The UC San Francisco research team tested 25 second-trimester pregnant women from Northern and Central California seeking care in San Francisco in 2008 and 2009 and found they had high levels of the chemicals in their blood, putting their babies at risk, according to the study published in Wednesday's Environmental Science and Technology journal.
Researchers believe the women's high PBDE levels were due to California’s strict flammability regulations enacted in the 1970s, which led manufacturers to add flame retardants to a wide variety of products, from electronics to furniture.
PBDEs may be toxic to the liver, thyroid and nerve development, according to the EPA.
We spoke with Ami Zota, a postdoctoral fellow at UCSF's Program on Reproductive Health and the Environment and lead author of the study, about what the findings mean and what can be done.
A: The average levels of PBDE chemicals are the highest reported to date among pregnant women worldwide. This was surprising, given that most PBDEs have been banned in California since 2004.
Q: Where are these flame-retardant chemicals coming from?
A: A couple of things. PBDEs since the mid-'70s have been added to many products we use in our everyday environments — couches, carpet padding, electronics — computers, TVs — a range of products. They’re also added to crib mattresses, children’s car seats, most products that have polyurethane foam in them have PBDEs in them, or now they have a replacement flame retardant.
Q: So are pregnant women getting exposed to these chemicals because when they're getting ready to have a baby they buy used cribs and car seats?
Q: How are they getting in the food supply?
A: They end up in the air in manufacturing. You throw stuff away and it ends up in a landfill. They’ve been found in polar bears and even house cats.
Q: So why study pregnant women?
A: There’s a wealth of research that shows these chemicals interfere with development and can lead to lower IQs later on.
Q: How sure are you that these chemicals can harm pregnant mothers and their babies?
A: Obviously things like brain development and IQ we consider multifactorial — there are many things contributing to how a child will grow and develop. We can’t say with certainty that at this level this effect will happen. We can say there have been studies done in places like New York where the levels were much lower than here where they did see relationships between PBDE and neurodevelopmental outcomes such as reduced IQ. We studied these factors because it’s an area where we can potentially intervene and eliminate it.
Q: How would we eliminate it?
A: We’re still replacing these chemicals with other chemicals that in many cases are structurally similar and have not been thoroughly tested. That was part of the problem — we did not thoroughly test these chemicals before we started to use them in the marketplace. Ultimately the goal is to go toward an approach where we’re thoroughly evaluating chemicals, particularly their effects on vulnerable populations such as pregnant women and developing children. What this shows is with these chemicals, even once they’re banned, you can’t get rid of them.
Q: Why are the levels of these chemicals higher in California women?
A: Californians are among the most highly polluted people in the world with flame retardants.
Q: More than people in developing countries like China and India?
A: Well, I must say, we have to look at where they’ve actually been measured. In my study, I summarized all the studies of pregnant women to date of PBDEs. There’s about 20. They included China, Japan, Sweden, Spain, Korea and various parts of the U.S. The levels in pregnant California women were 10 to 100 times higher than pregnant women in Europe and Asia, about two to three times higher than pregnant women in other parts of the U.S.
Q: Why would the levels be higher in California than other parts of the U.S.?
A: Technical bulletin 117, a unique flammability standard, unique to California. The standard does not require the use of chemicals, but what it does say is that furniture sold in California must be able to withstand an open flame for 12 seconds. The cheapest way to meet the standard is to use these flame retardants. And this standard was enacted in the 1970s.
Q: So it’s in stuff that’s still around?
A: Yes. The high levels are likely a result of California’s unique flammability standard.
Q: Are minority and low-income California residents disproportionately exposed to these chemicals?
A: The communities with the highest levels overall are low-income communities in California such as Oakland, Richmond and Salinas, all in Northern and Central California, mostly because those are the areas that have been studied.
This is an area that warrants further research. More of these chemicals may be released in older, secondhand furniture. The other thought is that secondhand furniture may be made differently, with cheaper chemicals and different barriers [to release]. The other thing we think is low-income housing quality may make exposure worse, like the ventilation.
Q: Do certain minority communities face more exposure?
A: Most of our study population was born in the U.S. What we’ve seen is if people are born outside of the U.S., like in Mexico, and migrate to the U.S., their exposures are already lower. The theory is Mexico used less of these chemicals, so an immigrant’s exposure in Mexico was lower than when they were in California. These chemicals stay in your blood for quite some time, for several years, even when you move.
Q: So what can low-income pregnant women do to prevent exposure?
A: This is a really difficult situation because often lower-income expecting mothers don’t have the resources to go out and buy a new couch or fancy furniture. If you have furniture that’s ripped or the foam is exposed, patch your furniture so there’s no exposed foam. The chemicals are in the food supply and accumulate in animal fat, so we can also eat lower on the food chain.
Q: What can the rest of us do to prevent exposure?
A: That’s a tough question. It requires a combination of individual and group behavior. Pregnant women can dust and wet mop their home, wash their hands frequently, try to avoid products made from foam. Ultimately, it’s very hard to avoid our exposures to these products because they’re so widespread. We need policy measures. There have been efforts to modify this technical bulletin 117. It’s never been shown to be effective to reduce fire-related injury or death, and there are other approaches to fire safety including fire-safe cigarette and building codes.
-- Molly Hennessy-Fiske
Photo: Ami Zota, a postdoctoral fellow at UCSF's Program on Reproductive Health and the Environment and lead author of a study released Wednesday that found the highest levels ever reported among pregnant women worldwide of toxic polybrominated diphenyl ethers (PBDEs), flame retardant chemicals largely banned in California in 2004. Credit: Ami Zota.