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What Fate for Brominated
Fire Retardants?
The widespread distribution and environmental effects of these persistent chemicals are driving preventive measures. REBECCA
RENNER
he presence of polybrominated diphenyl ether (PBDE) flame retardantstivroughoutdie world environment has begun to attract international attention. Researchers and environmental groups are concerned about emerging pollution problems, pointing both to the growing body of evidence that PBDEs are ubiquitous in the environment and to evidence suggesting that lowlevel exposures may produce detrimental health effects in humans and animals. European scientists and governments are at the forefront of this issue, but the problem is global, according to Mehran Alaee, a research scientist at Canada's National Water Research Institute, in Burlington, Ontario, whose group is responsible for most of the PBDE measurements in North America. "It's global because so far, everywhere we look we find measurable amounts of PBDEs," Alaee says. Although European governments are poised for action, PBDE manufacturers claim that such measures are premature and simplistic. Producers argue that bans and actions to remove these chemicals from the marketplace are overly cautious and are based on inadequate data. Legislative and regulatory control initiatives fail to account for the benefits of flame retardants in preventing fires, and little is known about the environmental fate and transport of proposed substitutes, according to Marcia Hardy, who chairs the Brominated Flame Retardants Industry Panel at the Chemical ManufactureTS Association in Washington, DC. The study prompting the most activity so far is a finding by researchers at Sweden's Karolinska Institute (1) that there are low levels of PBDEs in mothers' milk and that, although levels of other persistent organic pollutants, such as polychlorinated biphenyls (PCBs) and DDT, are decreasing, levels of PBDEs are increasing. Results such as these are the rationale for a draft European Union (EU) Human Health Risk Assessment's recommendation that action be taken to curb the use of penta-BDE (2), which is sold in relatively small quantities. "Penta is damned," says Gwynne Lyons, Toxics and Policy Advisor to Worldwide Fund for Nature-UK, "The political decision-making process, at least in Europe, will respond to the fact that no mother on earth wants her breast milk to be contaminated with flame-retardant chemicals." The EU includes restrictions against PBDEs under the European ecolabeling scheme and is likely to propose a much broader ban on their use in electrical and electronic equipment under a forthcoming directive on scrap from electronic devices. The Swedish research results are also prompting action in the United States, according to Larry
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© 2000 American Chemical Society
Needham, Centers for Disease Control and Prevention (CDC) director of toxicology. Needham notes that CDC will begin gathering data on U.S. exposure this summer. Unlike many persistent and ubiquitous organic pollutants such as PCBs or DDT, which are largely a legacy of the past, brominated flame retardants are in current, widespread use to prevent or deter fires in electronic devices, furniture, and textiles. PBDEs have been found in the body fat of many wildlife species, including sperm whales in the Atlantic Ocean (3). The latter finding suggests that even the deep ocean is now contaminated. Prompted by such findings, Sweden and Denmark have called for a ban on two types of flame retardants—polybrominated biphenyls (PBBs) and PBDEs and are urging international action. The largest-volume PBDE Members product on the market today is deca-BDE. But because of the German PBDE toxicity decreases as the number of bromines increase, Association of the deca-brominated compound is, at first glance, the Chemical Industries least likely to present a problem (4). Many researchers and voluntarily halted environmental groups believe, however, that in the enproduction of vironment, deca-BDE can PBDEs and break down to lower congeners. "The toxicity of octa- and PBBs in 1986. deca-BDE, coupled with the about their potential breakdown to penta is enough to warrant their removal from the market" argues Lyons
Consumption and use Brominated diphenyl ethers are a group of aromatic brominated compounds in which 1-10 hydrogen atoms in the diphenyl oxide structure are replaced by bromine atoms. Commercially available products are not pure substances—flame-retardant formulations consist of PBDEs containing anywhere from 3 to 10 bromine atoms. Three different flame retardants are available and are sold in the marketplace as penta-, octa-, and decabromodiphenyl ether; each product is actually a mixture of brominated diphenyl ethers. PBBs, PBDEs, and tetrabromobisphenol A (TBBPA) are the main types of brominated compounds used as flame retardants. PBDEs are the focus of current concerns for several reasons. PBBs— the first brominated organic compounds to be used— have been voluntarily phased out by manufacturers because of environmental issues. PBDEs have taken MAY 1, 2000/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 2 2 3 A
their place but are now being replaced, to some extent, by TBBPA. There is very little information available concerning TBBPA (4). The estimated annual global consumption of PBDEs in 1992 was 40,000 metric tons and consisted of 30,000 metric tons of decabromodiphenyl ether, 6000 metric tons of octabromodiphenyl ether, and 4000 metric tons of pentabromodiphenyl ether (2). Total PBDE consumption in that year corresponded to about 30% of the world market for all types of brominated fire retardants used. In western EuEverywhere w e rope, consumption of PBDEs accounted for about 26% of look, w e find the European market for brominated flame retardants in measurable 1996 (5). A 1999 analysis ind i c a t e d t h a t t h e s h a r e of amounts of PBDEs. PBDEs in the European market decreased to about 11% in 1998 (5V the decrease in con—Mehran Alaee sumDtion of PBDEs is esneNWRI ciallv pronoiinced in Permanv the Netherlands
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