A commonly used flame retardant, found in many chair cushions, is turning up everywhere from Virginia fish, to mothers’ breast milk to arctic animals.
Research shows the chemicals in question, brominated diphenyl ethers — or BDEs for short — easily move through the environment and are being found in remote rivers and other far-flung places where there are no obvious sources.
“It is the ultimate nonpoint source pollutant,” said Robert Hale, of the Virginia Institute of Marine Science.
No one knows exactly how the flame retardant enters the environment. It is widely used as an additive to polyurethane foam cushions, like those used in vehicle seats and furniture, to make them more fire resistant. Hale suspects that the chemical escapes from the foam as dust particles when discarded cushions begin to degrade.
Research by Hale and colleagues, published in the journal Nature last year, found that sewage sludge from wastewater treatment plants in Virginia, Maryland, New York, Texas and California all contained high concentrations of BDE, even when there was no obvious nearby source, such as a foam manufacturer.
Rather, Hale said the chemical more likely enters the wastewater plants through stormwater runoff, which may be accumulating BDE particles landing on city streets.
“Since we see relatively consistent levels in all of the sludges that we’ve looked at, we think it is a relatively continuous source to a wide number of sewage treatment plants,” Hale said. “And all of those sewage treatment plants do not have polyurethane foam manufacturing facilities near them.”
The chemical is long-lasting in the environment, and bioaccumulates in wildlife. When Hale and colleagues examined more than 1,000 fish from 322 locations in the Roanoke and Dan river basins in Virginia, they found that 89 percent of the fish contained detectable levels of BDE-47, one of the most common components of “Penta-,” the flame retardant mixture used in foam. Penta can constitute up to 30 percent of the weight of such upholstery foam.
A recent study in Canada found that women in the United States and Canada had the greatest amount of BDEs in their breast milk worldwide. The women had 40 times the level of BDEs as their counterparts in Sweden.
The United States accounts for 98 percent of worldwide use of Penta. Global production of Penta doubled to 8,500 tons annually from 1992 to 1999.
Penta BDEs can constitute up to 30 percent of the weight of protected upholstery.
Various types of BDE will be under discussion later this year when the Bay Program’s Toxics Subcommittee and its Scientific and Technical Advisory Committee present a workshop on emerging contaminants in the Bay watershed. The workshop stems from a commitment in the Toxics 2000 Strategy that calls on the Bay Program to explore whether various emerging chemicals of concern may pose a threat to the Bay watershed. The workshop aims to assess the risks posed by such chemicals and set research priorities.
With widely used chemicals such as BDEs, officials acknowledge it may be difficult for the Bay region to take action on its own. But they say the chemicals could be targeted for reductions through voluntary pollution prevention programs supported by the Bay Program. In Japan, BDE concentrations in fish have dropped because of voluntary reductions.
The catch is, no one can say with certainty what harm — if any — BDEs cause in humans, or the environment.
“The data suggest the compounds are not acutely toxic,” Hale said. “The concern for these is similar to what the concerns are for PCBs — chronic toxicity. They are not believed to be carcinogenic. There are some concerns, however, in terms of their endocrine disruptive capabilities.”
Endocrine disrupters are pollutants — such as PCBs, DDT-breakdown products, dioxins, herbicides and other chemicals — which can mimic or block endocrine system processes that help to guide development, growth, reproduction, behavior and other bodily functions. Research has linked endocrine disrupters with such impacts as deformed sex organs in wildlife and sex reversal in fish. Impacts in humans are less clear, but suspected as well.
Hale said some metabolites in BDE- breakdown products have “striking similarities” to some of those in thyroid hormones. They could affect early development in humans, he said, “but we don’t know at this point.”
Studies with mice in Sweden suggest the chemical can cause permanent disturbances in their behavior, memory and learning. Scientists say the persistence, and potential impacts, of BDEs are similar to PCBs, a chemical widely used as an insulator for electrical devices until it was banned more than two decades ago.
Because of the mounting concern, some forms of BDEs are being phased out in Europe under a “pre-cautionary principle” approach. But in the United States, where a “risk-assessment” approach is used, a chemical must be proved to be harmful before it is banned.
And while the problems that BDEs may pose to the environment are vague, the benefits are clear, according to manufacturers. Adding BDE to foam furniture padding, television casings and other plastics reduces by 45 percent the risk of death and injury from fire, they say.
“We’re not talking about aesthetics,” said Robert Campbell, a spokesman for Great Lakes Chemical Corp. “People use brominated flame retardants because they save lives.”
One thing that is certain is that the chemical is rapidly building up in the environment. A study published in the journal Environmental Science & Technology in April reported that BDEs were accumulating in the Arctic faster than either PCBs or dioxins. In the Arctic, BDE concentrations in ringed seals — the most common seal in the region, and the main prey of polar bears — have doubled every four to five years since 1981.
BDEs are considered a persistent organic pollutant, or POP, which means it does not readily break down in the environment. Such chemicals are notoriously hard to purge from waterways. For example, although the use of PCBs was banned 25 years ago, they continue to show up in fish both in the Bay and its watershed at levels sufficient to warrant consumption advisories in many areas.
Hale said the persistence of BDEs in the environment seems to be in the same ballpark as PCBs and DDTs, and therefore warrant the growing concern. “They are so persistent, and they are so bioaccumulative that there are going to be some impacts,” he predicted.