In a garage-like building in Madison, Wisconsin, wildlife toxicologist Sean Strom recalls placing a dead river otter on an operating table, taking hold of his lopping shears, and then removing the animal’s head. He did this often back in 2010. Afterward, with a scalpel, he’d make an incision over the abdomen, take out a few nickel-sized pieces of liver, and put them into a bag.
These tissue samples and 35 others taken from otters and bald eagles from the region would let Strom know what substances the animals were exposed to when alive. Packing them in dry ice, he sent them to a laboratory in Michigan and awaited the results.
The news wasn’t good: Great Lakes wildlife have high levels of polybrominated diphenyl ethers (PBDEs)—flame-retardant chemicals found in products such as textiles, couches, and electronics. Strom and his colleagues recently published their findings in the Journal of Great Lakes Research. The study found that the PBDE readings for bald eagles were higher than those for any other bird ever tested.
"Once you release them in the environment, they stay out there for years and years. They become ubiquitous. It’s become a worldwide problem."
There is growing concern about this class of chemicals, which have been linked to metabolic disorders in humans as well as obesity, low IQ, and decreased fertility. The United States Environmental Protection Agency classifies one type, decabromodiphenyl ether, as a possible carcinogen. In lab experiments on rats and mice, the compounds affected the thyroid and liver, and research in the field on American kestrels shows that PBDEs can delay egg-laying and make eggshells thinner. Much field research on flame retardants, however, hones in on how pervasive these chemicals are in the environment.
For the last six years, wildlife biologists in the Great Lakes region have been testing the eggs of tree swallows for contaminants. So far, the research shows elevated levels of flame retardants in the shells of eggs at some of the nearly 30 test sites. The scientists, from the U.S. Geological Survey, think that the contamination will be even more pronounced in the eggs of fish-eating birds, because flame retardants can accumulate in the tissues of fish that swim through polluted water. (A number of studies on flame retardants in fish confirm this.) As it happens, bald eagles and otters love fish.
So, what’s going on in the Great Lakes? Nothing that isn’t happening wherever products treated with flame retardants exist. The chemicals are showing up just about everywhere scientists look—and as far away as the Arctic. Most recently they were found in sharks and other marine life in Florida.
“Once you release them in the environment, they stay out there for years and years,” says Marta Venier, a chemist in the School of Public and Environmental Affairs at Indiana University. They also travel far and wide through the air and water. “They become ubiquitous,” she says. “It’s become a worldwide problem.”
In 2004, after evidence came out that two types of flame retardant (called penta- and octa-BDEs) were seeping into the environment, the industry voluntarily agreed to phase them out. A decade later, however, wildlife biologists and chemists are still finding these compounds in large quantities.The EPA is evaluating the toxicity of many flame retardants, but groups like the Natural Resources Defense Council advocate for an overhaul of the Toxic Substances Control Act, which would further regulate these substances.
“The fact that the levels are still pretty high could be cause for a concern,” says Venier of PBDEs. “We’re still exposed to them, both humans and biota.”
Now that we know PBDEs last longer than the Energizer Bunny, the next step will be figuring out how much environmental exposure wildlife (and humans) can handle before becoming affected. “And if the flame retardants get to those concentrations, they need to be regulated and removed,” says Thomas Custer, a Wisconsin-based research biologist with the USGS who is part of the tree swallow study.
The good news is that the industry is voluntarily replacing common brominated flame retardants with organophosphorus compounds. According to Venier, those chemicals don’t persist as long in the environment and at least seem to have fewer health concerns. (The jury is still out, though.) The bad news is we’ll still be importing products laden with PBDEs from abroad—as is the case with decabromodiphenyl ether found in electronics.
And otters and fish and birds are still taking them into their bodies, and giving us hints as to what chemicals humans may be taking in too—by eating those animals, swimming in a river, or just sitting on the couch.