PBDE's are chemical compounds that are used to make flame retardants. They can be found in almost anything that carries an electrical current or is flammable. They're in, for example, your TV, your computer, your cellphone, your car, your toaster and your sofa.
PBDE stands for polybrominated diphenyl ether – a compound which contains bromine atoms. PBDE's come in different forms, depending on the number and location of the bromine atoms. There are 209 possible variations. Often in the U.S. PBDE's are marketed with trade names such as DE-60F or Saytex 102E (among others). Variations of the polybrominated diphenyl ethers (PBDE's) include:
- pentabrominated diphenyl ethers (pentaBDE's);
- octabrominated diphenyl (octaBDE)
- and decabrominated diphenyl ethers (decaBDE's).
Penta and Octa BDE's are on the way out worldwide (are actually no longer produced in the US), but the chemical industry is waging a fierce fight to retain the use of the third major PBDE compound, Deca, which is the most widely used of the PBDE's – about 50 million pounds a year in the U.S. alone.
PBDEs are released into the environment during manufacturing operations, when products containing these chemicals degrade, or when the products containing the PBDE's are disposed.
WHY SHOULD I BE CONCERNED?
THE SHORT ANSWER:
PBDE's are everywhere, they accumulate and they spread. And they're really not good for us.
THE LONGER ANSWER:
Demand for flame retardants is up: The average "escape time" that a person has to get out of a burning home has dropped from 17 minutes in 1975 to only 3 minutes today, according to a study by Underwriters Laboratories released in October 2007. The reason for this is that plastics, from which so much of our consumer products are made, are made from oil, which is actually an accelerant in fires. And synthetic fabrics (according to the UL study) produce hotter fires and more toxic smoke than natural fiber furnishings. The higher fire load of consumer products and home decorations has effectively made home fires so dangerous that fire alarms sounding will often not provide adequate time for occupants to escape. The flame retardants for plastics therefore have become more critical than ever before. Increasingly stringent fire codes and flammability requirements, especially in building materials and consumer products, are driving demand for flame retardants steadily higher.
PBDE use has increased 40% from 1992 to 2003, and is forecast to grow by at least 3% per year from 2011; they are ubiquitous in consumer products.
Food is the major source of exposure for many contaminants, including DDT and PCBs. But food doesn't seem to be the culprit in this case: Since PBDEs are used as additive flame-retardants and do not bind chemically to the polymers, they leach from the surface of the product and easily reach the environment. In fact, Environmental Working Group calculations show that dust is likely to be a more important PBDE exposure route for children than food, as PBDEs migrate from furniture and electronics into house dust.
And they don't stay put: Sit down on a foam cushion and you're releasing countless, invisible PBDE particles. When the TV gets hot, still more escape and land in the dust in our homes. They rinse off our clothes in the laundry and run down the shower drain, winding up in sewage that's applied to farm fields as fertilizer.
And what about all that plastic in the ocean gyres or in landfills? It is slowly leaching PBDE's.
These chemicals have characteristics that make them intrinsically hazardous to humans and other animals: they are stable (persistent), they are fat seeking and they have the potential to act as endocrine disruptors. What is meant by these sorta innocuous sounding terms:
- persistent: they bioaccumulate, or build up, in fish and cats and Orcas and foxes – and people. Our bodies cannot get rid of these contaminates, so our levels just increase over time. We eat PBDEs when they contaminate our food, particularly meat and dairy products. They latch on to dust and other particles, so we breathe them in, or ingest them when dust settles on food or when children stuff their fingers into their mouths. Scientists look for PBDEs in breast milk because the chemicals stick to fat. In 1999, Swedish researchers reported that PBDE levels in women's breast milk had increased 60-fold between 1972 and 1997.
- Graph from NRDC1
- Similar dramatic increases were documented in California harbor seals, ringed seals from the Arctic, gull eggs from the Great Lakes and human blood from Norway.
- Graph: Ikonomou, MG et al, "Exponential Increases of the Brominated Flame Retardants, Polybrominated Diphenyl Ethers, in the Canadian Arctic from 1981 to 2000", Environmental Science and Technology 36: 1886-1892.
PBDE pollution has been found essentially everywhere scientists have looked: in the tissues of whales, seals, birds and bird eggs, moose, reindeer, mussels, eels, and fish; in human breast milk, hair, fat and blood; in hot dogs and hamburgers and the cheese we put on them; in twenty different countries and remote areas such as the North Sea, the Baltic Sea and the Arctic Ocean, on top of mountains and under the sea.2
- fat seeking: this causes them to magnify up the food chain, increasing in concentration at each successively higher level. Once PBDE's are released into the environment, they invariably find their way into humans, including pregnant women, where they pass to the developing fetus in utero or through the breast milk to the nursing infant. As evidence of fetal exposure, the infant at birth has levels of PBDE's that are up to 25% of maternal levels. And researchers have found that children's PBDE levels are about 2.8 times higher than their mothers.3 Research in animals shows that exposure to brominated fire retardants in-utero or during infancy leads to more significant harm than exposure during adulthood, and much lower levels of PBDEs are needed to cause harm to infants and children than to adults.
- endocrine disruptors: Many of the known health effects of PBDEs are thought to stem from their ability to disrupt the body's thyroid hormone balance, which plays an essential role in brain development. Laboratory animals showed deficits in learning and memory with exposure to PBDE's. Studies of mice showed that a single exposure to PBDEs caused permanent behavioral aberrations that worsened as the mice got older. One study, for instance, found that women whose levels of T4 (a PBDE) measured in the lowest 10 percent of the population during the first trimester of pregnancy were more than 2.5 times as likely to have a child with an IQ of less than 85 (in the lowest 20 percent of the range of IQs) and five times as likely to have a child with an IQ of less than 70, meeting the diagnosis of "mild retardation."4
- In addition to their effects on thyroid hormones and neurological development, PBDEs have been linked to a gamut of other health impacts in laboratory animals, from subtle to dramatic. In-utero exposures have been associated with serious harm to the fetus, including limb malformation, enlarged hearts, bent ribs, delayed bone hardening, and lower weight gain. The malformations of the fetus were consistently seen at levels much lower than doses harmful to the mouse mothers.5
- Only one commercial PBDE mixture has been tested for its ability to cause cancer, in a single study more than 15 years ago. High doses of Deca given to rats and mice caused liver, thyroid and pancreas tumors.
What does all of that mean, exactly?
Personal choices can make a difference. Buying furniture, fabric, cell phones or computers made without PBDEs is definitely a vote for a non-toxic future. You can help your kids with your buying habits, and by modeling social action for environmental change - by campaigning for a non-toxic future, the kind of future where mother's milk will regain its purity.