Among the chemicals that get attention for their worrisome effects on the environment and human health, flame-retardants come up again and again.
To mitigate fire hazards, manufacturers put these chemicals in everything from furniture to baby pajamas. But studies have raised concerns about the potential for flame-retardants to cause cancers, hormonal disruption, neurological impairment and other problems.
In response, companies have designed better, more environmentally friendly versions. But even these may pose risks, suggests a new study. Scientists have found what they suspect to be a breakdown product of one of the newer chemicals in the eggs of herring gulls that live throughout the Great Lakes Basin.
Herring gulls are a sentinel for other top predators, said Robert Letcher, an environmental chemist and ecotoxicologist at Carleton University in Ottawa, Canada. Like forensic detectives, he and colleagues working now to figure out exactly where the chemicals came from and how they’re getting into wild animals.
"We know what they are but we don’t know where they came from specifically and we don't know what effect they’re having on herring gulls and their developing eggs," Letcher said. "Clearly, whatever the source and whatever is involved in the process of forming these compounds is complex."
Fire-retardant chemicals often contain bromine atoms, which are good at smothering fires. And at least 75 brominated flame-retardants have been produced, including a group called PBDE’s. But studies have linked these chemicals to a range of health hazards, and researchers have detected flame-retardants in dust,food, baby gear and the bodies of both people and animals.
With growing concerns alongside tougher regulations, manufacturers have been trying to make more sustainable fire-retardants by, among other techniques, adding extra bromine atoms. The idea is that, by making the molecules heavier, they may be less likely to become volatile end get into the air.
That strategy may be backfiring, suggests the new study. Over the last year, Letcher along with colleague Da Chen and others have been sampling herring gull eggs in the Great Lakes. Their first round of tests revealed the presence of bromine. Next, they conducted a detailed chemical analysis on the compounds that are turning up in the eggs.
Their results, published in the journal Environmental Science & Technology, revealed a chemical structure that could be a breakdown product of a new kind of flame-retardant called SAYTEX 120. The researchers don’t yet have definitive proof, Letcher said, but the conclusion would make sense based on the chemistry involved.
"I can't say for sure," he said. "But I've spent over 10 years studying how metabolism can cause biological changes to chemical pollutants. And I’ve done a lot of work on brominated flame-retardants."
The new study draws more attention to the toxic nature of a wide range of common flame-retardants for both animals and people, and the need to find better solutions, said Arlene Blum, visiting Scholar at the University of California, Berkeley, and executive director of the Green Science Policy Institute.
Manufacturers must comply with strict fire-resistant regulations. And in the midst of a fierce debate, particularly in California, some companies and researchers argue that flame-retardants save lives.
But Blum said that, inside furniture foam, these chemicals suppress flames for just a few seconds. Meanwhile, they produce more smoke and more carbon monoxide than chemical-free foams. Sprinkler systems, she said, would be more effective at fighting fire than chemical coatings.
"Industry says the chemicals don’t get out of the products and if they do get out of products they don’t get into living organisms," she said. "This is one more example that they do."