The EPA recently announced a list of chemicals to be reviewed. On the list: flame retardants or PBDEs. Scientists say these chemicals, used to reduce the flammability of upholstery and carpeting, accumulate in our bodies. Host Jeff Young talks with Dr. Julie Herbstman of Columbia University about a new study that indicates PBDEs may affect the intelligence of young children.
YOUNG: From the Jennifer and Ted Stanley Studios in Somerville, Massachusetts, this is Living on Earth. I’m Jeff Young. It’s an encore edition this week, we’ll hear some of our favorite stories from the past year—think of it as recycling.
The Environmental Protection Agency head Lisa Jackson has put improving chemical safety near the top of her agenda. And among the chemicals of concern are the flame-retardants known as PBDEs. These brominated chemicals in those flame-retardants raise red flags for health researchers. In the journal Environmental Health Perspectives scientists report a link between PBDEs in the blood and reduced IQ in young children.
Julie Herbstman, from the Columbia University Center for Children's Environmental Health in New York helped write the study, which tested pregnant women and their babies.
HERBSTMAN: Well, we measured PBDEs in the umbilical cord blood of about 329 non-smoking, healthy women who are living in New York, and then we follow the kids over time and monitor their neurodevelopment using some standard tests and see how the kids are doing as they grow.
YOUNG: So, you’re able to keep track of them as they’re growing up; what did you find out?
HERBSTMAN: Yeah, well we have very dedicated study participants, who allow us to keep contacting them over time. And we found that kids who had the highest levels of PBDEs in their umbilical cord blood scored on average lower on these neurodevelopmental tests at multiple time points.
YOUNG: How big a difference did you find?
HERBSTMAN: You know the different neurodevelopmental tests have different scales. At four years the tests measure something like IQ, and what we found was that there were about five points difference. So, the kids with the highest exposure scored on average about five points lower than the kids with the lower prenatal exposures.
And this is similar in a scale of what we’ve seen for lead. We know that no exposures are safe, but these small changes might have meaningful differences, especially for the kids, who have, you know, low baseline scores to begin with.
YOUNG: Are the differences in IQ because of the chemical exposure or can we know that?
HERBSTMAN: We’ve adjusted for lots of other things that we know effect children’s development and IQ. We’ve looked at environmental tobacco smoke, mothers’ IQ, material hardships and other social stressors, breastfeeding, and we found that even after we’ve adjusted statistically for all of these other factors, we still see associations between PBDEs.
YOUNG: So, it’s a likely suspect?
HERBSTMAN: It’s a likely suspect.
YOUNG: How do these flame retardant chemicals – these PBDEs – get into us anyway?
HERBSTMAN: The primary route of exposure is thought to be dietary, and for infants this would include breast milk. But, more recently people have been thinking that it could also involve the ingestion of dust that contains PBDEs, and especially for infants and toddlers who are on the ground a lot and put their hands in their mouths a lot this could be a very important source in addition to breast milk.
YOUNG: You know as a parent of two small children I got to say losing IQ points that sounds very worrisome. But I also understand that this is a preliminary study – how concerned should we be here?
HERBSTMAN: Yeah, so this is really the first study of its kind in North America. The levels in North America are just much higher than they are in Europe or in Asia, so this is the first study of its kind and we’re really waiting to see if these results are replicated in other populations.
YOUNG: I guess a part of the irony with this is the reason we use these chemicals is partly motivated by improving child safety. I mean there was a good reason to want to make a child’s mattress less likely to go up in flames.
HERBSTMAN: It’s true, it’s true. It’s really important to have good fire safety, but there are alternatives we could be using that are chemical-free solutions like using less flammable materials, or changing product designs that would make them more fire-resistant, or we could be using less toxic chemicals.
YOUNG: So, EPA is taking a closer look at this general group of chemicals, these PBDEs. I understand some of them are already in the process of being phased out – what’s the status of these things?
HERBSTMAN: Yeah, some have been phased out through a voluntary cooperation between industry groups and EPA. Recently, EPA has listed these chemicals as ‘chemicals of concern’ and that means that they’ll require more testing in some states like California, Hawaii, New York have banned the manufacture, use, or sale of these compounds.
YOUNG: In the meantime, is there a way consumers can minimize exposure?
HERBSTMAN: Yes, that’s not really part of our research, but other groups like the Environmental Working Group have come up with some suggestions that include like looking at foam items because these compounds are used – these chemicals are used – in foam and textiles. So, you could take a look at your car seats or mattress pads to make sure that anything with a ripped cover or appears to be breaking down is not in use anymore.
They also suggest vacuuming with a special filter that would be more effective at removing the dust. But, I should say though these are probably good first steps, but these suggestions haven’t been validated yet, so probably preventive policies might be more effective at reducing overall exposure.
YOUNG: Epidemiologist Julie Herbstman at Columbia University’s Mailman School of Public Health. Thank you.
HERBSTMAN: Thanks so much for your interest in our work.
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