In an attempt to quantify the concentration of flame retardant chemicals ingested by and present on humans, researchers from The Columbia Center for Children’s Environmental Health conducted analyses of 25 homes of mothers and their children in two boroughs in New York City.
The study also included researchers thoroughly wiping down the hands of the mothers and their corresponding children to determine the concentration.
Until 2013, manufacturers coated furniture and other household products with polybrominated diphenyl ethers and brominated flame retardant chemicals in order to meet fire safety standards that were implemented in the 1970s. The study mentions that the specific chemicals were not needed in order to adhere to fire safety standards. However, without their inclusion, it would have been difficult to meet the requirements without the addition of other flame retardant chemicals.
After 2013, the federal government banned polybrominated diphenyl ethers due to its significantly high levels of toxicity to humans. Fire safety standards also weakened when the “open-flame test” was abolished in favor of the “smolder test,” which involves dropping a lit cigarette on an item of furniture to see how quickly it catches on fire. A chemical mixture called Firemaster 550 was added to the furniture during the manufacturing process instead of being chemically bound to it. This, in turn, caused some of the flame retardant particles to fuse with dust particles.
Mothers and children living in Manhattan and the Bronx were tested from 2012 to 2013, the last year before the chemicals were banned from use in the flame retardant industry. Researchers collected dust and hand wipe samples during this sample period of time.
In order to proceed with the project, the researchers set up a unit called the Siblings-Hermanos birth cohort and invited mothers ranging in age from 27 to 44 to participate. All the mothers invited were previously enrolled in the CCCEH “Mothers and Newborns Study.”
Young children were expected to have higher traces of concentrations of harmful flame retardant chemicals than adults on their hands, because they tend to stay on the floor more. They are also likelier to ingest related chemicals due to the higher chance that their hands would make contact with their mouths during play.
Children who were approximately 3 years of age were tested, along with the mothers from 25 apartments in the two boroughs. This was conducted via a home visit permitted by consenting mothers. During the home visit, a field technician vacuumed the surface area of the living space for dust. After vacuuming, the technicians wiped down the hands of the mothers and their children. The hand wipe procedure was only conducted in 11 of the 25 households due to resource constraints.
After the sample collection, the researchers interviewed the participants to account for factors such as cleaning patterns, living conditions, maternal age, marital status, race and ethnicity, smoking status and type of floor covering. Additionally, the researchers noted the season in which the samples were obtained.
The demographics of the mothers who were interviewed in the studied skewed 40 percent African American and 60 percent Dominican. The study writes, “We detected no significant differences in household or lifestyle characteristics between the 11 households with and the 14 households without handwipe samples except that women were more likely to be employed in households where handwipes were collected.”
The results displayed that two flame retardant chemicals were consistently found in the dust samples from all of the houses that were tested. After hand wipe analysis, flame retardant chemicals were found in all of the samples. Certain chemicals like TBPH and TBB—additives in the Firemaster 550—were found in the hand wipes. TBB was found in all samples except one.
The measured concentration of polybrominated diphenyl ethers was much higher in the hand wipe samples from the children than in the samples from their corresponding mothers. The study posits that this is due to a difference in age-specific behaviors, such as children being more likely to crawl on the floor.
The results matched most of the predictions made prior to the analyses, except for the fact that hand wipe samples taken from females saw higher concentrations of the chemicals than samples taken from males.
At the end of the study, the researchers explain that while they found traces of certain chemicals on the hand wipe and dust samples, they did not account for other classes of flame retardants that may have also been used to replace polybrominated diphenyl ethers.
This indicates that the data may not be quantified accurately and may in fact provide underestimating information for the total exposure to flame retardants for mothers and children living in New York City.