Forth Worth (Tex.) Star-Telegram, January 20, 2007
TOXIC CHEMICALS LINKED TO DUST
[Rachel's introduction: Researchers tested the breast milk of 46 first-time mothers in the Boston area. Though they only obtained dust samples from 11 of the women's homes, they found a statistically significant link between the levels of PBDEs [toxic flame-retardant chemicals] found in the breast milk and in the dust collected in their homes.]
By Scott Streater, Star-Telegram Staff Writer
A new study suggests that people are routinely exposed to potentially harmful chemical flame retardants by ingesting household dust laced with the toxic chemicals, a fact that concerns health researchers who fear that children are at greatest risk.
The study, conducted by researchers at Boston University's School of Public Health, is the first to link the presence in people of the chemical flame retardants to exposure to common dust, which can be inhaled in the air or ingested in food.
And because infants tend to crawl on the floor, where dust accumulates, they are likely exposed to higher levels of the toxic substances, which could place them at risk of developing neurological problems, researchers say.
The flame retardants -- called polybrominated diphenyl ethers, or PBDEs -- have been in widespread use in the United States since the 1970s and are commonly found in carpet padding, television sets, computer wire insulation, mattress stuffing, waterproof jackets and many other products. The chemicals are added to products to help prevent the spread of fire.
But studies have measured the flame retardants in virtually every American tested, at levels that are the highest in the world.
A growing number of researchers suspect that PBDEs can cause reproductive and neurological problems, disrupt hormonal balance and, at high concentrations, increase the risk of cancer.
A Star-Telegram project last year found that chemical flame retardants may be common in local residents' bodies.
What it means
The Boston University study raises further concerns about widespread exposure to polybrominated diphenyl ethers, or PBDEs, and the possible health effects.
What researchers found
Researchers tested the breast milk of 46 first-time mothers in the Boston area. Though they only obtained dust samples from 11 of the women's homes, they found a statistically significant link between the levels of PBDEs found in the breast milk and in the dust collected in their homes.
"I think what our work shows is that the indoor environment is a significant source of exposure to PBDEs," said Tom Webster, an epidemiologist at Boston University who led the study.
How it got there
Webster said researchers aren't certain how the chemical flame retardants get into the environment. He said he suspects that the chemicals may turn into a gas and attach themselves to dust particles as they waft through the air.
A Star-Telegram project last year found the chemical flame retardants in some local residents, too.
Working with Dr. Arnold Schecter, a public-health physician at the University of Texas School of Public Health in Dallas, the Star- Telegram paid to have blood samples from 12 Tarrant County residents analyzed for 83 toxic chemicals, including 15 of the most commonly used PBDEs. The analysis found low levels of 14 of the PBDEs in the study participants.
The Star-Telegram analysis mirrored national studies indicating that most Americans have these chemical flame retardants in their bodies.
Chemical manufacturers maintain that the flame retardants save lives and that there's no definitive link between the PBDEs commonly measured in people and health problems.
But some government and industry leaders are moving to phase them out.
The Legislature in Washington state is moving forward on a bill that would ban the three most commonly used PBDEs. It would be the first state to adopt such legislation, which could receive final approval as early as this month.
U.S. manufacturers have agreed to voluntarily halt production of two of the most toxic brominated flame retardants, but not the one in widespread commercial use today. Many companies that sell products containing PBDEs, including Ford, Dell and IBM, have found alternatives.
The federal Environmental Protection Agency recently unveiled draft risk assessments of four common PBDEs. The draft assessments were conducted by a panel of scientists who are trying to establish a safe level of daily exposure to PBDEs, above which health problems might occur. The safe levels in the draft assessments are very low.
All four PBDEs being studied by the EPA were measured in the Tarrant County residents who participated in the Star-Telegram project.
Should I be worried?
Some researchers fear that people are routinely exposed to PBDE levels near the threshold where the EPA draft assessments suggest that health problems could occur.
That's especially true of children, who crawl and put virtually everything they touch into their mouths, said Heather Stapleton, an environmental chemist at Duke University who has done extensive research on the issue.
Staples compares PBDEs to lead. Many children with lead poisoning were exposed to the toxic metal by ingesting contaminated dust.
"It almost seems like this [PBDEs] could be the next version of lead coming through," she said. "We don't know as much about the toxicity of these compounds as we do of lead. But we definitely find very high levels in indoor dust that are going to be an exposure route for children."
If that's true, and PBDEs are a health concern, that should be enough to persuade regulators to demand alternatives to the PBDEs, Webster said.
"Flame retardants are useful because stopping fires is good," he said. "But we probably want to have ones that are not toxic."
For more information
For an overview of the Boston University study, go to: pubs.acs.org/subscribe/journals/esthag- w/2007/jan/science/kb_pbde.html.
The study will be published in the peer-reviewed journal Environmental Science & Technology.
FACTS ABOUT PBDEs
What are polybrominated diphenyl ethers (PBDEs)?
Synthetic chemicals that help prevent the spread of fire by impeding the chemical reaction that causes it. PBDEs are commonly found in polyurethane foam products, such as the padding in furniture, as well as in textiles, television sets and computers. But they can also be found in food and household dust. They have been measured in the bodies of virtually every American who has been tested.
What are the possible health effects?
The main concern is that PBDEs build up in the body over a long time. Data on how PBDEs affect people are scarce, and no one knows what levels trigger health problems. But animal studies have shown that PBDEs harm the nervous system and alter hormonal functions and the development of reproductive organs. Industry officials say the levels that have been measured in people and in the environment are too low to cause problems.
SOURCES: Bromine Science and Environmental Forum, federal Agency for Toxic Substances and Disease Registry
Copyright 2007 Star-Telegram