Pillows, vehicle seats key sources of flame retardants.

Nov 24, 2009

Imm P, L Knobeloch, C Buelow and HA Anderson. 2009. Household exposures to polybrominated diphenyl ethers (PBDEs) in a Wisconsin cohort. Environmental Health Perspectives doi: 10.1289/ehp.0900839.

Pillows and vehicle seats may be important household contributors to flame retardant exposure in humans.

Researchers have tracked the most significant sources of human exposure to one type of flame retardant chemicals – polybrominated dipheylethers (PBDEs) – by using a new kind of portable x-ray analyzer that can detect bromine levels in household items.

Topping the list were sleeping pillows and vehicle seat cushions whose bromine levels were significantly associated with PBDE levels measured in the participants' blood. Bromine levels ranged dramatically from product to product and house to house, even among similar pieces of furniture or electronics.

PBDEs are used to reduce the flammability and burning rate of a number of consumer products including furniture, electronics and textiles. PBDEs are widespread throughout the environment, contaminating food, household dust and air. Studies have also detected the flame retardants in wildlife and humans around the world.

Exposure to PBDEs is of concern as animal studies suggest they may impact neurodevelopment. Human studies also reported links with testosterone and thyroid hormone levels.

While recent research suggests that exposure to PBDEs occurs primarily indoors, the household items that contribute most to exposure had not been identified before the publication of this study.

Wisconsin researchers reported that individuals who sleep on pillows that have a high PBDE concentration, as estimated based on their bromine content, had increased blood PBDE levels. Owning a vehicle whose seats had a high bromine content was also associated with higher PBDE exposure.

The PBDE content of household items however varied widely and depended on the materials used in their manufacture. Researchers for instance found that the mean bromine levels was substantially higher in pillows made of polyurethane foam (3,646 parts per million) compared with those made of polyester fibers (107 parts per million) or feathers (6 parts per million).

In addition, vehicle seats made of cloth upholstery had bromine levels that were almost 25 times higher than those made of leather. Items with the highest bromine content were computers and televisions with averages of about 30,000 and 95,000 parts per million, respectively.

These results were obtained after measuring the blood concentration of PBDEs in 29 men and 15 women. The bromine concentration of household items was determined using a portable device using X-ray fluorescence. Researchers also measured the concentration of PBDEs in household dust but, contrary to previous studies, found no association with PBDE blood concentrations. Though this research provides new information regarding the potential sources of PBDE exposure, larger studies evaluating a greater number of products will be needed to fully assess this question.