Polybrominated diphenyl ethers (PBDEs)

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants, first produced commercially in the 1970s. PBDE production constitutes 25 percent of all flame retardant production. Polybrominated diphenyl ethers (PBDEs) are structurally similar to known human toxicants polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), dioxins and furans. These classes of chemicals have similar mechanisms of toxicity in animal and human studies. Additionally, PBDEs persist and bioaccumulate in humans and animals. In 2000, production of decaBDE constituted 80 percent of total global PBDE production.

Both pentaBDE and octaBDE were no longer produced in the U.S. as of 2004. In 2009, the same two chemicals, pentaBDE and octaBDE, were listed as persistent organic pollutants (POPs) under the Stockholm Convention. The same year, three manufacturers of decaBDE agreed to stop producing the chemical within three years. (However, a major substitute for decaBDE is decabrominated diphenylethane (DBDPE), which is similar in structure, persistence, and bioaccumulation.) Even with the phaseout of their manufacture and use in new products, PBDEs continue to persist in existing furniture, household dust, animals, humans, and sewage sludge. According to the Centers for Disease Control, "since PBDEs are not chemically bound to the flame-retarded material, they can enter the environment from volatization, leaching, or degradation of PBDE-containing products." PBDEs have been found in sewage sludge in concentrations as high as 33mg/kg.

2010 Tests of San Francisco Sewage Sludge Find PBDEs, Triclosan
On August 10, 2010, the Food Rights Network announced in a news release that "Independent tests of sewage sludge-derived compost from the Synagro CVC plant -- distributed free to gardeners since 2007 by the San Francisco Public Utilities Commission in their "organic biosolids compost" giveaway program -- have found appreciable concentrations of contaminants with endocrine-disruptive properties. The independent tests were conducted for the Food Rights Networkby Dr. Robert C. Hale of the Virginia Institute of Marine Sciences."

In an August 6, 2010, letter reporting on his findings to the Food Rights Network Robert Hale wrote: "A sewage sludge-derived compost from the Synagro CVC plant, distributed by the San Francisco Public Utilities Commission in their "compost give away" program, was analyzed for synthetic pollutants.  Several classes of emerging contaminants with endocrine disruptive properties were detected in appreciable concentrations, including polybrominated diphenyl ether (PBDE) flame retardants, nonylphenols (NPs) detergent breakdown products and the antibacterial agent triclosan." PDFs are attached here of the letter and the data:

Human Exposure
While the Centers for Disease Control points its finger at dietary sources of PBDEs, the Silent Spring Institute published a paper in 2008 claiming that house dust is a more significant source of contamination than diet. PBDEs have been measured (and found to bioaccumulate) in fish. Mothers pass their PBDE loads to their infants through breastfeeding, as PBDEs are found in breastmilk. Tests of Americans in 2003-2004 found levels of BDE-47 (a tetraBDE present in commercial pentaBDEs) in nearly all participants and several other PBDEs in greater than 60 percent of participants.

Toxicity
In animal studies, "PBDEs alter development of the brain and reproductive system and disrupt thyroid hormones." However, despite their widespread use, the health effects of PBDEs on humans are not yet well understood. Studies of PBDEs on mice show developmental neurotoxicity. Other studies point to the possibility that PBDEs are endocrine disruptors. Chemist Arlene Blum concurs with suspicions that PBDEs interfere with thyroid hormones as the chemicals are structurally similar. She fears that PBDEs contributed to the illness and death of her cat, Midnight, who tested extremely high for PBDEs. According to her: "When tested in animals, fire retardant chemicals, even at very low doses, can cause endocrine disruption, thyroid disorders, cancer, and developmental, reproductive, and neurological problems such as learning impairment and attention deficit disorder. Ongoing studies are beginning to show a connection between these chemicals and autism in children."

PBDEs in California
Technical Bulletin 117 (TB117) is "a unique California flammability standard that requires polyurethane foam to withstand exposure to a small open flame for twelve seconds." It was first implemented in 1975. Until 2004, manufacturers met this requirement with penta-brominated diphenyl ether (pentaBDE), a PBDE. In 1999, North America accounted for 98% of global pentaBDE usage, largely because of TB117. California banned PentaBDE in 2003, but toxic flame retardants continue to be used. A study by the Silent Spring Institute found that Californians have double the amount of pentaBDEs in their blood compared to the national average.

PBDEs Banned in the Stockholm Convention
In its fourth meeting, May 4-8, 2009, the Conference of Parties, decided to add several PBDEs to the Annex A of the Stockholm Convention, a list of persistent organic pollutants (POPs) to be phased out internationally. These chemicals are: tetrabromodiphenyl ether (tetraBDE) and pentabromodiphenyl ether (pentaBDE), which are the main components of commercial pentabromodiphenyl ether, and hexabromodiphenyl ether (hexaBDE) and heptabromodiphenyl ether (heptaBDE), which are the main components of commercial octabromodiphenyl ether (octaBDE).

Related SourceWatch articles

 * Biosolids
 * Sewage sludge
 * Food Rights Network
 * Flame Retardants
 * Brominated Flame Retardants

External resources

 * Green Science Policy Institute
 * Seth D. Newsome, June-Soo Park, Bill W. Henry, Arthur Holden, Marilyn L. Fogel, Janet Linthicum, Vivian Chu, and Kim Hooper, "Polybrominated Diphenyl Ether (PBDE) Levels in Peregrine Falcon (Falco peregrinus) Eggs from California Correlate with Diet and Human Population Density", Environmental Science & Technology, June 11, 2010.
 * Melissa Rose, Deborah H. Bennett, Åke Bergman, Britta Fngstrm, Isaac N. Pessah, and Irva Hertz-Picciotto, "PBDEs in 2−5 Year-Old Children from California and Associations with Diet and Indoor Environment", Environmental Science & Technology, March 2, 2010.
 * Linda S. Birnbaum and Daniele F. Staskal, "Brominated Flame Retardants: Cause for Concern?", Environmental Health Perspectives, January 1, 2004

External articles

 * Marla Cone, California's poor, Mexican American kids highly exposed to flame retardants, Environmental Health News, April 20, 2011.
 * Arlene Blum, "Flame retardants, policy, and public health: past and present," 4th International Conference on the History of Occupational and Environmental Health, June 2010
 * Arlene Blum and Linda Birnbaum, "Halogenated Flame Retardants in Consumer Products: Do the Fire Safety Benefits Justify the Health and Environmental Risks?," 5th International Symposium on Brominated Flame Retardants, April 201
 * Arlene Blum, "Killer Couch Chemicals," Huffington Post, August 16, 2007
 * Lisa Stiffler, "They Are Everywhere, They Accumulate and They Spread; Lawmakers Considering Strongest Ban Ever in U.S. PBDEs: Chemical Flame Retardants Pose Threat to Humans, Environment," The Seattle Post-Intelligencer, March 28, 2007.
 * Arlene Blum, "Chemical Burns," New York Times, November 19, 2006
 * Marla Cone, "Californians have world's highest levels of flame retardants", Environmental Health News, October 1, 2008.