My pal Joplin is a canine lint trap. Dust and dirt and bits of fluff leap at her from sidewalk and sofa as though her cushy black coat were exerting an irresistible gravitational pull. I don’t mind a little dirt, myself, but Joplin does. She plops herself down to apply that prehensile pink paint roller tongue to all of her coat within reach, and then she licks her little doggy wrists and squeegees her face with them. I hate to see it. All this hygiene might have made sense in pre-industrial days, but dust just ain’t what it used to be.
Environmental health experts learned in the 1980s that house dust can be a significant source of exposure to hazardous pollutants such as lead and pesticides, especially for dogs, cats and human toddlers, mouthy denizens of the indoor dust zone.Now it turns out that relatively new toxic synthetic compounds widely used in consumer products are blowing around in your dust bunnies, too—among them, flame-retardants called polybrominated diphenyl ethers, or PBDEs, and stain, water and grease repellants called perfluorochemicals, or PFCs.
These latter chemicals, the PFCs, are better known by their trademarked names—Teflon® and Gore-Tex®, to name two. Flame-retardant PBDEs are more anonymous but equally ubiquitous in the household. They are commonly used in foam cushions, synthetic fabrics, and in the plastic housing of electric and electronic equipment such as coffeemakers and laptops. PBDEs can make up as much as 30 percent by weight of your stereo or television’s plastic housing, according to a 2005 article in the journal Environmental Science and Technology.
Both types of chemicals get into house dust in more or less the same ways. When the television or nonstick pan heats up, the compounds volatilize and then settle on surfaces, and as treated foam and fabrics degrade, flame-retardant and stain-repellant particles crumble into your dust. Not just into your dust but also into your dog, new research shows. Earlier this year, toxicologists at the Environmental Working Group, a Washington, D.C.– based nonprofit, collected blood samples from 20 pet dogs and 37 pet cats. The researchers pooled dog samples into one batch and cat samples into another and found high levels of PBDEs and PFCs in both.
What are the health effects of these indoor pollutants? “We’re really just starting to generate data,” says Linda Birnbaum, of the EPA’s Experimental Toxicology Division in Raleigh, N.C., and an expert in indoor exposures to PBDE. “But we know that flame-retardant PBDEs have been linked to developmental, reproductive and neurological defects in lab animals; poor immune function in marine mammals; thyroid and liver tumors in rodents; and low sperm counts and poor sperm quality in humans. One study found an association between high PBDE levels in women and undescended testicles in their sons.” For their part, stain and grease repellants—PFCs— have been shown to cause tumors at multiple sites in rats and mice and to damage their reproduction, growth and immune systems, Birnbaum says.
Only a few studies have focused specifically on the health impacts of synthetic chemicals on dogs. One shows a link between applications of the lawn herbicide 2,4-D and bladder cancer in Scotties and several associate formaldehyde emissions from carpeting with seizures and other disorders. But many environmental health and veterinary experts believe that chronic exposure to synthetic industrial pollutants in house dust may be at least partially responsible for skyrocketing cancer rates in dogs these days, and, Birnbaum believes, for the extraordinary rise in feline hyperthyroidism in the last 30 years. “The cat sits on that nice warm TV or sits on the sofa and grooms, grooms, grooms,” Birnbaum says.