The Center’s previous research has linked early life exposure to a common class of flame-retardants called PBDEs with attention problems and lower scores on tests of mental and physical development in children. The latest results appear in the journal Emerging Contaminants.
Beginning in the 1970s, manufacturers added PBDEs—persistent brominated flame-retardants—to couches, textiles, electronics and other consumer products to comply with flammability standards. In 2004, they began phasing out PBDEs and started using newer alternative flame-retardants, including TBB and TBPH, which are brominated flame-retardants and components of the commercial mixture Firemaster 550®. Little is known about the health effects of TBB and TBPH in humans, though they have been linked to reduced fertility and endocrine disruption in animal models.
Researchers visited the homes of 25 mother-child pairs enrolled in the CCCEH Sibling-Hermanos birth cohort, which began in 2008. When children were 3 years old, dust was collected from their homes and hand wipes were collected from mother and child; these samples were then analyzed for flame-retardant compounds.
Signaling the widespread persistence of the phased-out PBDEs and the prevalence of their potentially toxic substitutes, investigators found that both PBDEs and the newer brominated flame-retardants, TBB and TBPH, were in 100 percent of house dust samples. On average, levels of TBB and TBPH in house dust were higher than PBDEs. Likewise, PBDEs and TBB were found in 100 percent of hand-wipe samples, and TBB was found in 95 percent of the samples. Paired mother and child hand-wipe concentrations were correlated; however, children typically had higher levels of all flame-retardants on their hands than their mothers.
The study is the first comparison of PBDEs, TBB, and TBPH in house dust and handwipe samples from maternal-child pairs. Results are consistent with other studies which have demonstrated that toddlers tend to have higher exposure to flame-retardants when compared with adults, likely because of the amount of time they spend on the floor.
“The extent to which young children are exposed to these chemicals is cause for concern given the known neurodevelopmental risk of PBDEs and the potential toxicity of their substitutes,” says Whitney Cowell, the study’s first author and a PhD candidate in the Department of Environmental Health Sciences at Columbia’s Mailman School.
“Toddlers are being exposed to replacement flame-retardant chemicals that we know little about,” says senior author Julie Herbstman, associate professor of Environmental Health Sciences. “Future research needs not only to focus on understanding the toxicity of these compounds, but also on how exposure occurs in the home and what behaviors and policies can be used to reduce personal exposure.”
Additional co-authors include Heather Stapleton of the Nicholas School of the Environment at Duke University; Matthew Perzanowski of the Mailman School; and Darrell Holmes, Lehyla Calero, and Catherine Tobon of the Columbia Center for Children’s Environmental Health. The research was supported by the National Institutes of Health (grants ES021806, ES017051, and ES09089) and by the Passport, Forsythia, and Fine Foundations. During preparation of this manuscript, Whitney Cowell was supported by the National Institute of Environmental Health Sciences (grants ES023772, ES007322) and the Environmental Protection Agency (grant FP-91779001).