Endocrine Disruptors VI: PBDEs in Dust

July 15, 2009
By Kathryn Au

Household products are coming under increasing scrutiny as scientists examine the health effects of commonly found chemicals. One such chemical may be found in dust. Polybrominated diphenyl ethers, or PBDEs for short, are a type of chemical compound that contain many bromine atoms. They are used as a flame retardant so that household products don’t burn so easily. PBDEs make homes safer by preventing fire. When foams or plastics containing PBDEs get heated at high temperatures, bromine atoms break off to quell the fire. PBDEs can be found in foam products like mattresses cushions, plastic products like computers and other electronics, wire and cable insulation, and adhesives. Some polyurethane products can be made of up to 30% PBDEs by weight. Unfortunately, PBDEs can break off from these products over time, getting into the air as dust.

People are becoming more concerned over the health effects of PBDEs. PBDEs are related to polychlorinated biphenyls (PCBs), a type of chemical fluid also used for many of the same uses as PBDEs. No more PCBs could be made in the US after the 1970s because of their high toxicity and potential to cause cancer.

Few studies have been done to show health effects of PBDEs on humans, but numerous studies on laboratory animals give us reason to worry. PBDEs are endocrine disruptors—that is, they act like hormones and interfere with our bodies’ ability to control hormone levels. PBDEs, in particular, disrupt thyroid hormones, which regulate metabolism. Small doses of it affect attention, learning, memory, and behavior in laboratory animals [1]. At high doses in young animals they can impair brain development, and in adult animals they can damage reproductive organs or cause tumors [2]. Exposure of cats to PBDEs is related to hyperthyroidism, or an overactive thyroid[3]. Scientists are now trying to test whether PBDEs can be linked with infertility, obesity, autism, hyperactivity, and birth defects [3].

The danger with PBDEs is that they persist in our environment and bioaccumulate. In other words, they do not break down or degrade easily, and they build up in the bodies of animals higher up in the food chain. They have been found in animals, human blood, and even human breast milk. Mothers can pass PBDEs onto fetuses in the womb or babies through breastfeeding. Children also receive a higher exposure to PBDEs because they are more likely to breathe or eat PBDE dust by playing on the floor or putting hands and toys in their mouth.

Americans have higher levels of PBDEs in their blood compared to Europeans, with concentrations highest in the West, especially California. Californians may have twice as much of it in their blood, and ten times as much of it in their houses, than people in the Northeast [4]. This may be due to California’s strict fire safety laws. While such laws increase the safety of homes by protecting against fires, they may put residents at greater health risks due to the higher amount of PBDEs in their homes. This could be of special concern to the Native community because California has the largest Native American population—over 600,000—of any state, according to the 2000 U.S. Census.

In light of concerns over the health effects of PBDEs, many states are considering or have already carried out bans on several types of PBDEs. In 2004 many major electronics companies agreed to phase out two of three major PBDEs (Octa and Penta) in their products. Environmental health groups are pushing for a ban on the third type, Deca, which can degrade into the other forms and be toxic. All three PBDEs are currently banned in Europe.

At the household level, there are a few ways to reduce exposure to PBDEs.

• Use a vacuum with a high-efficiency particulate air (HEPA) filter, which gets rid of 99.9% of dust particles.
• Be careful when handling carpets with foam underneath, and vacuum after handling.
• Avoid being near furniture with crumbling or decaying foam.
• Remove furniture with any exposed foam, or cover the holes with a sturdy cloth.
• Do not reupholster (put new coverings on) old furniture in a house with children or pregnant women.
• Use naturally flame-resistant products like wool and cotton.