Flame Retardants Building Up Within Us

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Flame retardants building up within us
By ANDRÉ PICARD

Tuesday, February 15, 2005 - From Tuesday's Globe and Mail


Those dust bunnies lurking under the bed may not be as innocuous as you think.

New Canadian research shows that household dust is the principal source of exposure to flame retardants, a class of chemicals that has sparked a heated debate among scientists, some of whom believe regular exposure may lead to serious learning and developmental problems.

Toddlers in particular are ingesting significant amounts of polybrominated diphenyl ethers (PBDEs), according to a study to be published in a forthcoming edition of the journal Environmental Science and Technology.

"Dust is the greatest route of exposure to brominated flame retardants," said Miriam Diamond, a professor in the department of geography at the University of Toronto. "It makes a lot of sense. Toddlers are close to the ground, which is where many of those flame retardants are — in carpets, in furniture. The chemicals accumulate in the dust."

In her paper, Dr. Diamond estimates that the average urban Canadian ingests 155 to 1,965 nanograms daily of PBDEs, with the highest levels found in babies but decreasing as people age. (A nanogram is one-billionth of a gram.)

But breast-feeding infants have much higher exposures, from 24 to 28,680 nanograms daily. Earlier research found that flame retardants are commonplace in the breast milk of Canadians but concluded that despite high levels, women should continue to breastfeed because the known benefits outweigh the known risks.

Dr. Diamond said she wondered how pregnant women accumulated these chemicals in their bodies.

She found that household dust is the principal source of exposure for adults, followed by food. (Research commissioned by The Globe and Mail and CTV News found PBDEs in almost all common foods tested.)

Flame retardants are used in the manufacture of a broad range of materials, including foams, textiles and plastics. As a result, most household products, including sofas, carpets, hair dryers, televisions and computers, give off PBDEs.

These invisible chemicals turn into dust that sticks to windows, gathers in small balls under the bed and snuggles in with the lint in the dryer.

A study published last month found PBDEs in the dust of every home tested. The research, done in the Washington area, found concentrations of 780 to 30,100 nanograms of PBDEs per gram of dust. Scientists estimate that as a result, toddlers in these homes ingest 120 to 6,000 nanograms daily.

Erin McAllister, a Vancouver mother of a toddler, heard of PBDEs when she participated in a study of breast milk. Now she has just learned that daughter Jessica, 17 months, probably ingests flame retardants in household dust, as well.

"That's just lovely. Yuck, yuck," she said in disgust. "I feel kind of helpless. I don't want these poisons in my body, but I'm breathing it every day and my children are breathing it and eating it every day."

Barbara Thorpe of Clean Production Action, a Montreal-based consumer group, said that if Canadians were more informed about the levels of PBDEs in their home environments — from dust to food — they would be angry.The problem is, nobody knows the impact on human health.

All the research on PBDEs has been conducted on laboratory animals. When animals are exposed to high levels of PBDEs, they develop memory problems and disruptions to the thyroid hormone.

Some scientists believe that in humans, that could translate into learning disabilities and stunted growth.

Some postulate that the stunning rise in attention-deficit-hyperactivity disorder is due, in part, to children's exposure to flame retardants.

Linda Birnbaum, associate director for the National Health and Environmental Effects Research Laboratory of the U.S. Environmental Protection Agency, said the concerns are justified, even if it is hard to nail down the impact of PBDEs on health.

"These are not chemicals you are going to get a dose of and immediately die. They are chemicals that are present in very low levels in our bodies . . . but they build up. And part of the concern is, they will continue to build up to a level that they will cause problems."Dr. Birnbaum said the EPA is trying to develop standards for safe levels of exposure to PBDEs, but establishing a cut-off is not easy.

For scientists and environmentalists, however, the solution is to aim for the lowest exposure possible by finding alternative forms of flame retardants and making consumers aware of these chemicals' origins and where they accumulate.

Although individuals must wait for governments to regulate PBDEs, they can take a few simple steps to reduce their exposure, beginning with improving ventilation in their homes, getting rid of carpets and vacuuming a little more often.