Many of us are familiar with DDT and thinning eggshells, and we may have heard about the dangers of PCBs. But most of us are unaware that another group of ubiquitous and toxic chemicals is in our midst.
Many of us are familiar with DDT and thinning eggshells, and we may have heard about the dangers of PCBs. But most of us are unaware that another group of ubiquitous and toxic chemicals is in our midst. They're called polybrominated diphenyl ethers or, mercifully, PBDEs.
PBDEs are a group of chemicals used to slow or resist fires in a staggeringly wide variety of consumer goods, including furniture and automotive upholstery, sound insulation, and carpets, as well as in computers, mobile phones, and a broad range of consumer electronics. You can also find them in human breast milk, where levels of PBDEs are rising rapidly, especially in North America.
It's now commonly said that we live in a chemical soup. Chemical contaminants turn up with predictable frequency in our water, air, and food chain. But there's something about finding toxic chemicals in human breast milk that seems well, wrong. Mother's milk is somehow supposed to be inviolable, a private source and sanctuary for nursing infants, a pure and whole, unsullied drink of goodness. Finding PBDEs in mother's milk is unmistakable and compelling evidence of chemical trespass.
In the fall of 2004, Northwest Environment Watch, a Seattle-based group, measured PBDE levels in the breast milk of 40 new mothers from the Pacific Northwest 10 each from British Columbia, Washington, Oregon, and Montana. The results were shocking. Every one of the mothers in the study had PBDEs in her breast milk, at concentrations roughly 20 to 40 times higher than Japanese or Swedish mothers. Other North American studies have had similar findings.
Alexis Doctor was one of the mothers whose breast milk was sampled. Ms. Doctor lives with her husband and her son Ethan in a pleasant, greenly landscaped section of Richmond, BC, not far from the Steveston docks, just south of Vancouver. Ethan was a few months old when Doctor volunteered for the study.
"I felt that I had the time, the energy, and the desire to find out more. Now that Ethan was in the world, I really wanted to know more, so that I could do more for him." Doctor waited several weeks for test results but breastfed in the meantime, convinced that this was the best option for her baby. When results arrived indicating she had PBDEs in her breast milk, she was surprised and concerned.
That concern is shared by federal agencies in Canada, who have had PBDEs on their radar for some time. Recent studies by Health Canada found that concentrations of PBDEs in Canadian mothers' breast milk have increased by a factor of 11 between 1991 and 1992 and 2001 to 2002. Environment Canada is conducting its own studies.
What's the Problem?
PBDEs are an environmental concern because they are very persistent in the environment, because they bioaccumulate in the tissues of living organisms, and because they are toxic. Lab studies have shown negative impacts on learning behaviour and on the functioning of the thyroid system. A major concern is that concentration levels in the tissues of wildlife, especially marine mammals, are doubling every two to five years.
PBDEs, like DDT, PCBs, and other persistent organic pollutants, turn up in breast milk because they are lipophilic, which means that they attach themselves to human fat cells. Because they are also persistent, tissue levels in breast milk tend to build up over time.
The situation can be reversed, though. Since the decline in usage of PBDEs in Europe, levels in breast milk have levelled off there.
Studies Are Under Way
The conclusion reached by Health Canada is that current levels of PBDEs, from all sources of exposure, are not harmful to human health. Nevertheless Environment Canada has called for PBDEs to be categorized as "toxic" under the Canadian Environmental Protection Act (CEPA). With PBDEs categorized as CEPA-toxic, a lengthy process would ensue. While the process may lead to virtual elimination more or less tantamount to an outright ban the categorization might only institute risk reduction measures.
At the same time that federal agencies are assessing the health and environmental impacts of PBDEs, the only remaining manufacturer of penta-PBDE and octa-PBDE two of the leading types of PBDEs on the market is phasing them out of the North American market. But the industry is defending the use of deca-PBDE, which is widely used in computers and home electronics.
Consumer Goods the Culprit
Why are levels in Canadian bodies so much higher than those in European or Japanese bodies? Food is the major source of exposure for many contaminants, including DDT and PCBs. But, if preliminary conclusions based on Health Canada data are correct, then food is not the culprit in this case. According to Samuel Ben-Rejeb, Health Canada spokesperson, levels of PBDEs in Canadian diets are "completely comparable to European numbers." If higher concentrations in food aren't the basis for the higher levels in Canadian breast milk, there must be other factors involved. But what?
One clue is that North America accounts for about 95 percent of global use of penta-PBDE, arguably the most toxic of the PBDE group. Another possibility is that the huge amount of deca-PBDE in consumer products may be breaking down in the environment to form penta- and octa-PBDE.
University of Toronto scientist Miriam Diamond sampled PBDE levels in house dust and in the coatings on the insides and outsides of windowpanes. Approximately half the contamination coating Ontario windowpanes was deca-PBDE. Diamond believes deca-PBDE should be restricted on a precautionary basis. Further, Diamond suspects that concentrations are greatest in homes with new consumer items that are still off-gassing PBDEs.
Does all this mean that breast milk is unsafe? Not at all. Despite containing various contaminants, breast milk remains an irreplaceable source of nutrition, critical hormones, protective immune factors, and promoters of neurological development. Breastfeeding is good for mothers, too. Benefits include reductions in the incidence of anaemia and some gynaecologic cancers in women, including pre-menopausal breast cancer.
What to Do About It
Other jurisdictions have taken strong action on PBDEs. Europe has banned penta- and octa-PBDEs and is looking closely at deca. The state of California has also banned penta- and octa-PBDEs. Companies such as IKEA, Motorola, and Ericsson have taken pro-active approaches, replacing PBDEs in their products with safer alternatives.
When asked if participating in the study had changed her buying habits, Ms. Doctor replied, "I know that some manufacturers don't use PBDEs in their products. So when we go to buy our next couch or cellphone or computer, I'm going to look for one without PBDEs. It's safer."
What can careful parents do to protect themselves and their children from exposure to PBDEs? Here are some quick tips:
Consult these websites for information on PBDE-free products:
Ms. Doctor emerged from her experience feeling less safe but more determined. "By participating in the study, I realized that I took a lot of things for granted. Living in Canada, I felt that I was safe. But I realized that, whether I'm sitting at a computer, or working at an office job, or working in a factory, it may not make a difference. I don't take as many things for granted as I once did."
Personal choices can make a difference. Buying furniture or computers made without PBDEs is definitely a vote for a non-toxic future. But personal choices can only go so far. PBDEs, like other contaminant issues, are at least as much a social as a personal issue and challenge. You can also help your kids not only with your buying habits, but also by modelling social action for environmental change, by campaigning for a non-toxic future, the kind of future where mother's milk will regain its purity.