Does Danger Lurk in Your Carpet and Cell Phone?
New Faculty Member Heather Stapleton Studies the Risks Posed by Flame-Retardant Chemicals in the Environment p.2
Stapleton’s natural curiosity, coupled with a lifelong fascination with aquatic animals, has taken her far from her childhood home in Candor, N.Y., a rural, landlocked community of about 5,000 in the bucolic Finger Lakes region.
“I was one of those kids who loved animals, especially sharks. I wanted to be the classic marine biologist,” she remembers. As an undergraduate at Southampton College, however, her classes involved research cruises and water-quality sampling in bays and estuaries, and she became increasingly aware of the impact pollution was having on the organisms that lived there.
Realizing where her true interest lay, she switched her major to chemistry, and, after graduation, enrolled in the graduate program in environmental chemistry at the University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory.
It was there, while studying the accumulation of PCBs— polychlorinated biphenyls—in the Great Lakes’ food web that Stapleton took the plunge into the murky world of PBDEs.
Given their widespread use and chemical similarities to PCBs, and the scant attention that had been paid to them in American scientific journals, “it just made sense to start studying them,” she says. “There was clearly a need.” Her doctoral dissertation spawned three peer-reviewed papers and led to a two-year National Research Council Postdoctoral Fellowship at the National Institute of Standards and Technology.
Stapleton’s speedy ascendance up the scientific ranks has earned her a reputation as a tireless and meticulous researcher. But visitors to her office, or to her old Web site at the Chesapeake Biological Laboratory, are presented with a different, more fun-loving image: A photo of her posing, mock-seductively, on the seat of a Harley-Davidson with her long blonde hair cascading over one shoulder and a pair of high heels dangling over the handlebars.
She smiles when asked about it. “I was at a friend’s wedding,” she explains. “We were all dressed up and everyone in our lab took turns posing on this guy’s bike. It was a joke. Chemists are allowed to joke.”
All joking aside, Stapleton’s emergence as one of America’s top experts on PBDEs comes at a time when there is increasing evidence of the chemicals’ pervasive presence in our environment.
Studies by other researchers have found that PBDEs are rapidly accumulating in rivers, oceans and other aquatic ecosystems in Europe and North America. Elevated concentrations of PBDEs have been found in the fat tissue of species as diverse as polar bears, killer whales and farmed salmon, in locations as geographically far-flung as Greenland, Norway, the Great Lakes and the Pacific Northwest.
High levels also have been documented in human breast milk and serum, especially in North America.
“Studies of breast milk and serum have shown that the U.S. population has the highest levels of contaminants in the world, probably because PBDEs are found in so many of the products we use every day,” says Stapleton.
In a paper published last year in Environmental Science & Technology, she reported finding high concentrations of the chemicals in materials as seemingly innocuous as house dust and clothes dryer lint. Editors of the journal have selected the article as one of the seven top environmental papers published in 2005, based on its potential implications for environmental and human health.
“We found elevated levels in about 5 percent of the households we tested. Smaller houses or apartments tended to have the highest levels,” Stapleton notes.
By using the U.S. Environmental Protection Agency’s estimates of how much dust a toddler between the ages of one and four can be expected to ingest, she and her colleagues determined that children in the homes with the highest levels could be ingesting as much 1,200 nanograms of PBDEs from dust each day.
“These are not lethal exposures,” she says, “but they are alarmingly close to the levels above which we see behavioral effects in laboratory animals. Over time, it’s possible that these sublethal exposures may affect IQ and learning in some children, as well as endocrine activity.”
Research by scientists in Europe and North America has shown that sublethal concentrations of PBDEs cause liver and neurodevelopmental toxicity and adversely affect thyroid hormone levels in test animals such as fish, rats and mice.
In light of growing concerns, the European Union banned the use of penta- and octa-BDEs in 2004. No federal regulatory action has yet been taken to ban or restrict their use in Canada or the United States, but several states, including California and Maine, have issued statewide bans and the U.S. Environmental Protection Agency reached a voluntary agreement with the sole domestic manufacturer of the penta- and octa-mixtures to cease their production at the end of 2004.
Providing policymakers with the information they need to make accurate risk assessments and prudent decisions about the future use of PBDEs is vital, Stapleton says. Having access to the resources and colleagues needed to meet that challenge is one of the main reasons she jumped at the chance to join the Nicholas School faculty.
“The great thing about the Nicholas School is that it has such incredible diversity,” she says. “You have ecologists, toxicologists, policy experts and others working side by side. Great science is often the result of great collaborations. This is definitely a place where that can happen.”
Tim Lucas is the Nicholas School’s national media relations and marketing specialist