The new PCBs?

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The new PCBs?

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The good thing about polybrominated diphenyl ethers is that they have

probably prevented many household items from bursting into flames. The bad

thing is that they could be threatening our health. MARTIN MITTELSTAEDT reports

 

By MARTIN MITTELSTAEDT

Saturday, June 5, 2004 - Page F7

 

When thinking about hazardous chemicals, Canadians usually don't consider

the mattresses they sleep on, the couches in their living rooms or the hard

plastic casings around their computers and television sets.

 

But all these everyday items may contain compounds that are starting to

worry scientists because they are close chemical cousins to the notorious

PCBs, banned in the seventies.

 

Canadians are unlikely to have day-to-day contact with polychlorinated

biphenyls, which were mainly used as insulators in electrical transformers,

but the same can't be said about these new chemicals, known as

polybrominated diphenyl ethers.

 

Used as flame retardants, PBDEs are found in almost everybody's homes. For

instance, up to 30 per cent of some polyurethane cushions are made of the

chemicals.

 

The use of PCBs was curtailed after the discovery in the 1970s that they

were contributing to bizarre and monster-like birth defects in wildlife.

Subsequent research has also linked them to an equally frightening finding:

They interfere with normal neural development and diminish human

intelligence, memory and attention spans, with the strongest impact among

exposed children.

 

The worry is that PDBEs will have the same deleterious effects as PCBs.

" There is enough information currently available. We're repeating history

in terms of the PCB story, " says Miriam Diamond, an environmental scientist

at the University of Toronto who has conducted research on PBDEs. She

believes that they should be banned immediately and replaced with safer

alternatives.

 

Dr. Diamond has found the chemical in surprising -- and worrisome --

places, such as in the grime sticking to the inside surfaces of windows in

Toronto homes.

 

Different PBDE formulations are used for foam cushions and computers. Her

research uncovered mainly the type used in electrical equipment, probably

the result of evaporation from computers.

 

Many scientists and environmentalists are also concerned that the flame

retardants, and other novel chemicals like them, may be contributing to the

recent rash of behavioural ailments in children. For example, attention

deficit disorder was practically unknown before PBDE use became widespread,

but it is now commonplace.

 

Dr. Diamond says this speculation about a link should be studied. " I'd like

to see the medical community be more proactive in investigating connections

between exposure to [PBDEs], as well as dioxin-like PCB contaminants, and

attention-deficit-disorder-type effects that we're seeing in kids, " she says.

 

Although there has been no human experiments on PBDEs, rodents subjected to

the chemicals have been found to suffer from impaired thyroid function and

a diminished ability to learn.

 

PBDEs have a single virtue: They have probably have saved many lives by

preventing TV sets, couches, car seats and computers from bursting into flame.

 

But the trouble is that, after nearly three decades of use, they have

escaped the products in which they were originally used. By processes that

are not fully understood, PBDEs have seeped out of computer casings and

foam cushions into the wider environment.

 

And almost everywhere scientists look, they are finding PBDEs in both

wildlife and humans, where it is being detected in blood and in breast

milk. They don't know if the chemicals in our bodies evaporated from

furniture, leaked from computer wastes in dumpsites, or came from

manufacturing plants, or a combination of all three.

 

PBDEs are building up in wildlife and humans at a breathtaking rate.

Concentrations in people are doubling about every five years, and are up

about 100-fold in the past 30 years, according to a recent research paper

by Ronald Hites, a professor of environmental and analytical chemistry at

Indiana University.

 

Prof. Hites found Americans to be 20 times more contaminated than people in

Europe, where there has been more aggressive regulatory concern over the

PBDEs and cutbacks in their use. Canadian levels are slightly lower than in

the United States, but far higher than in Europe.

 

Although levels in most people are still far below amounts that would cause

health concerns, that may not be true of the entire population. When

analyzing concentrations in human breast milk, researchers have found that

a small minority of women, perhaps about 5 per cent of the population, are

statistical outliers, with concentrations in their bodies about 10 times

higher than the average readings. These people, and their children, may be

at far greater risk than the general population.

 

One U.S. study released last year found that one woman had 1,078 parts per

billion in the fat of her breast milk, a level that was found to be a

problem with PCBs. But another woman in the same study had only 9.5 ppb.

 

" There is already some part of the population that is over the limit, " says

Tom Muir, an environmental economist at Environment Canada.

 

It is not known why readings vary so wildly, and scientists say it should

be an immediate research priority to see why these women have elevated

readings.

 

" Are these people that are constantly changing their furniture -. . .

bringing in a fresh set of foam that is degassing? Or are these people that

have very old furniture and their furniture is basically pulverizing and

they're receiving the dose in dust? " asks Mehran Alaee, a scientist at the

National Water Research Institute in Burlington, Ont., who has studied the

chemicals.

 

Although even household dust and window grime have been found to contain

PBDEs, diet is believed to be the main route of human exposure. People are

eating trace amounts in their foods, and because the chemicals do not

readily degrade, levels are accumulating.

 

Like many other industrial contaminants, PBDEs tend to become embedded in

the fatty tissues of living things. When absorbed into an animal, the

levels then concentrate at higher and higher levels on the way up the food

chain, reaching an apex in top predators and, at the top of the human food

chain, in breast milk.

 

The diet link is one reason why experts are not yet recommending that

people try to minimize PBDE exposure by tossing out couches containing

polyurethane foam and staying away from computers.

 

But many scientists are suggesting that greater care be taken in the

disposal of computers, mattresses and other products containing the flame

retardant. Dr. Diamond says the products should be gathered up and

destroyed in high-temperature incinerators.

 

The potential PBDE threat has begun to cause widespread alarm in the

scientific community, among manufacturers of consumer products and, more

recently, among governments.

 

Some of that alarm will be on display next week at the University of

Toronto, where many of the world's leading experts on the flame retardants

will hold three days of seminars presenting the most recent findings on

such topics as the amount of PBDEs in U.S. supermarket foods.

 

As if to further underline this worry, Health Canada and Environment Canada

jointly recommended last month that some forms of PBDEs be considered toxic

under the country's environmental laws and be virtually eliminated.

Regulatory authorities in Canada seldom find a chemical so dangerous that

they feel compelled to designate it as toxic, and the action follows a

flurry of similar moves abroad.

 

Some of the more commonly used types of PBDEs will be banned by the

European Union, starting in August. Three U.S. states, California, Hawaii

and Maine, have followed suit with similar bans to take effect in either

2006 or 2008. In the United States, Great Lakes Chemical Corp. has decided

to cease production of the type of PBDEs used as a flame retardant in

polyurethane foam by the end of the year.

 

Many big consumer-product companies are using flame retardants that do not

contain the chemicals. For instance, Ikea doesn't allow PBDEs into its

furniture. Dell, the big computer manufacturer, has also said it uses

alternatives.

 

In recommending the ban, Health Canada believes that Canadians currently do

not have worrisome exposures and will be safeguarded by the recommendation,

says Kathy Hughes, an official who worked on the proposal to restrict the

chemicals. But she says the government doesn't want to see further

increases of the chemical in breast milk and blood.

 

Scientists are debating whether regulatory authorities have acted with

enough alacrity to head off potential problems.

 

Mr. Muir at Environment Canada has extrapolated recent rates of increases

in PBDE levels, and says that in less than a decade, about 10 per cent of

women would have breast milk containing amounts of the chemicals found to

cause health effects with PCBs.

 

There has been a huge amount of computer equipment and furniture sold in

the past two decades, and no one knows how quickly these products will leak

their store of PBDEs into the environment. So even with the flurry of bans,

concentrations could rise for years.

 

Mr. Muir thinks that this means PBDEs could represent an ominous new

environmental problem. " We could be sitting on a real bad scene because we

don't know the leak rates, " he says.

 

Martin Mittelstaedt is The Globe and Mail's environment reporter.