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The 'New PCB'

Flame retardant toxins show up in BC mothers' bodies.

By Clark Williams-Derry 31 Aug 2005 | TheTyee.ca
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Could common household items--such as couches, carpets, and computers--pose a threat to your family's health?

Unfortunately, it's quite possible.

Now, I'm not talking about some sort of malaise brought about by post-industrial overconsumption. My concern is far more specific.

If you live in North America and have furniture that contains polyurethane foam, it's a pretty good bet that you've got chemical flame-retardants known as PBDEs (polybrominated diphenyl ethers) in your home. And as scientists are now discovering, PBDEs are showing up in people's bodies at increasing levels and carry a range of potential health risks including deficits in childhood brain development and subtle hormonal imbalances.

For decades, PBDEs were added to furniture, industrial fabrics, and consumer plastics -- not only in North America, but throughout the industrialized world. These kinds of products undoubtedly needed some kind of flame suppressant. Plastics and foams are, after all, made from petroleum, and once ignited they can burn fiercely.

Safety paradox

But paradoxically, the same compounds that were intended to make our homes safer have actually imposed a new risk. In the late 1990s, scientists discovered that levels of PBDEs in people's bodies were skyrocketing, doubling every two to five years. Worse, testing on laboratory animals suggested that PBDEs can pose some of the same risks as their chemical cousins, the PCBs. As with PCBs, a single dose of PBDEs administered to a laboratory animal during a critical phase of early development can cause permanent aberrations in memory and behavior. "Background" levels of PCBs -- the levels to which someone could be exposed in a fairly ordinary diet in the 1970s and 1980s -- are known to impair the human immune system and reduce IQ, and some scientists worry that PBDEs may have some of the same effects.

By the time governments halted the use of PCBs in the last 1970s, it was too late: the toxic genie was already out of the bottle. PCBs proved very durable, breaking down very slowly in the environment. Today, nearly three decades after they were removed from commerce, virtually every person tested, anywhere on the planet, has traces of PCBs in their bodies.

The same is now true of PBDEs, at least in the industrialized world. Recent tests in Japan, Europe and North America have detected PBDEs in virtually everyone examined, as well as in fish, wildlife, foods and housedust. A February 2005 study, for example, found that Canadian foods were among the most contaminated in the world, with PBDE levels up to 1,000 times higher than those found in tests in European countries.

BC breast milk

The compound is now ubiquitous, particularly in North America, where the use of PBDEs in furniture foams has been most concentrated. PBDE levels in human breast milk, for example, are between 10 and 40 times higher in the US and Canada than in Northern Europe and Japan.

New evidence now suggests that the threats posed by PBDEs in North America may actually be eclipsing those of PCBs. Data from a study coordinated by the Seattle-based research center Northwest Environment Watch, and released last week by California EPA scientists at an international conference in Toronto, shows that 30 percent of new mothers from British Columbia, Washington, Oregon and Montana had more PBDEs in their bodies than PCBs. A similar study released earlier this year found that half of all subjects tested had more PBDEs than PCBs in their fatty tissues.

Some scientists, in fact, have dubbed PBDEs "the new PCBs": the new, ubiquitous, harmful, and durable contaminant that can threaten neonatal development.

Dangerous dust

An interesting -- and probably significant -- side note to the Northwest Environment Watch study was that there was no correlation between PBDE and PCB levels in people's bodies. A person with high levels of PBDEs could have low levels of PCBs, and vice versa. This suggests that the two chemicals may get into people's bodies through different pathways. The principal source of PCB contamination in people seems to be food, particularly fish. As for PBDEs, scientists are still uncertain, but a recent exposure modeling study by scientists from the University of Toronto suggests that ordinary house dust, containing minute quantities of PBDEs sloughed off from furniture and other household goods, may be the principal route of exposure in people.

The bottom line of the study of moms from British Columbia and the Northwest is that, even though PCB levels are still higher than PBDE levels, we may be fast approaching a point at which PBDEs are more of a concern than PCBs.

And from this, we can draw three lessons. First, we should be paying close attention to PBDE levels in the coming years, to see whether PBDE levels continue to rise in people. Fortunately, the most troublesome forms of PBDEs were removed from the North American marketplace last fall. But that doesn't mean that PBDE levels in people have halted their meteoric rise; crumbling foam furniture and other consumer products may continue to be a reservoir for contamination for decades.

'Genie back in the bottle'

Second, we should be looking at ways of removing the tons of PBDE-laden products that are still in people's homes. So far, most of the political attention paid to PBDEs has focused on removing them from commerce. This is all well and good, but it fails to address the literally billions of pounds of PBDEs already sequestered in homes and workplaces.

And third, we need to learn our lesson about the risks posed by untested chemicals. In retrospect, it should have been obvious that PBDEs posed some risk, as their chemical structure is very similar to that of PCBs, dioxin and DDT. So that alone should have triggered some elementary testing requirements before the compounds were used widely in commerce. But it didn't.

At some point, though, we've got to learn the lesson, and take steps to make sure this sort of chemical fiasco -- releasing potentially hazardous compounds without adequate testing -- doesn't keep happening again and again.

Unfortunately, there's no way to put the PBDE genie back in the bottle. But if we learn our lesson well, we can prevent ourselves from releasing any more -- so that scientists of the future won't be worrying about some new compound they've dubbed "the new PBDEs."

Clark Williams-Derry is the research director for Northwest Environment Watch, a Seattle-based research center that tracks key trends for the Pacific Northwest, including pollution. For more information on this study, see www.northwestwatch.org/toxics/toxics05.asp.  [Tyee]

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