We’re polluted from head to toe and though scientists can now measure minute amounts of chemicals in our bodies, no one knows the long-term health effects
Apr. 21, 2006. 06:08 AM
NANCY J. WHITE
Sarah Winterton is many things: a 45-year-old mother of three teenagers, a Toronto resident, a program director – and a toxic chemical dump.
Blood and urine samples show that her body is home to 16 respiratory and 38 reproductive toxins, 19 chemicals that disrupt hormones and 27 carcinogens. Stored in her body are traces of heavy metals, such as lead, arsenic and uranium, and chemicals used in pesticides, flame retardants and stain repellents. DDE and DDT, DMTP, HCB, PBDE 47 and 99, PCBs and PFOS – this is just a taste of the alphabet soup swishing through her.
She wonders about the air she breathes, the tinned food she buys, the chemically protected mattress she sleeps on. “There are likely thousands more chemicals in me,” she says. “It’s not a great picture to have of yourself.”
But it’s as common as a snapshot.
Studies of volunteers in Europe, the U.S. and Canada show the same results. Coursing through our bodies is a complex chemical cocktail, the by-product of a modern life of industrial emissions, treated food and endless consumer products – microwave bags, fast food wrappers, nail polish, computer casings – laced with synthetic substances.
“We are the guinea pigs in the largest uncontrolled science experiment in history,” says Rick Smith, executive director of Environmental Defense.
The Toronto-based watchdog group sampled 11 volunteers across Canada – including Winterton, its program director, and Vancouver Island artist Robert Bateman – for 88 harmful chemicals and detected 44 on average in each person. The results of the testing, done at special labs in Quebec and Texas for $1,500 per person, is described in the report Toxic Nation, released last fall.
For years scientists have measured levels of toxic chemicals in wildlife and done specific studies on breast milk, childhood lead exposure or occupational hazards. But now this technique of sampling human tissues and fluids, known as biomonitoring, is being used by environmental groups and governments to get a broader sense of our body burden, or the chemicals carried within us. Next year Health Canada will conduct its first widespread biomonitoring testing on about 5,000 people. The Centers for Disease Control in the U.S. has been doing it since 2001.
Biomonitoring is turning pollution into a much more personal matter and helping to revitalize the political debate internationally. Many man-made chemicals on the market have never been thoroughly tested for human safety. The Canadian Environmental Protection Act is scheduled for review this year, and many advocates want to see the law beefed up, similar to proposed legislation in the European Union.
“Canada is increasingly falling behind,” says Smith.
While scientists can now measure increasingly minute amounts of more substances in humans, they’re still studying what it all means. A manufactured chemical in a person’s blood or urine doesn’t imply disease. Or even risk of a disease. Only exposure.
“Just because it’s there doesn’t mean it’s going to hurt you,” says Bruce Caswell, senior manager of environmental health and safety with the Canadian Chemical Producers Association.
But it doesn’t mean it’s not hurting you either. We experience a constant barrage of synthetic stuff, even in the womb. Doses differ as do genetic and physiological vulnerabilities.
“None of this belongs in our bodies. Period,” says Riina Bray, a family physician at Women’s College Hospital’s Environmental Health Clinic.
Researchers suspect these toxic chemicals have links to a number of cancers, including breast, testicular and non-Hodgkin’s lymphoma, not to mention reproductive disorders and learning disabilities. But little is proven. Scientific consensus moves slowly and environmental health research is tricky. It’s about as clear as an oil slick.
“I don’t think there is cause for alarm, like with a pandemic flu, but there is cause for concern,” says medical epidemiologist Don Wigle, an affiliate scientist at the University of Ottawa’s McLaughlin Centre for Population Health Risk Assessment. “We need a precautionary approach to reduce exposures. No one wants to wait for all the answers.”
There are no roads where David Masty lives. No industrial smokestacks. No manufacturing emissions. Yet this chief of Whapmagoostui First Nation on the shores of Hudson Bay, one of the Toxic Nation volunteers, had 51 of 88 chemicals in his body, including a high level of mercury.
“It doesn’t matter where you are,” says Masty, 60. “The pollution is transported through the air and from the products we use in our homes.”
There’s the scented lotion absorbed into your skin. The coloured polish you spread on your nails. The soft vinyl toy your child enjoys. These may be made with phthalates, chemicals widely used to soften plastics and carry fragrances. In laboratory animals some phthalates cause organ damage, disrupt hormones and cause reproductive harm. Some phthalates have been banned in children’s products in Europe, and Canadian manufacturers have agreed to remove some from soft, chewable toys here. The soup you eat from a tin can? Bisphenol A, a hormone disruptor in rodents, can leach from the can. Your non-stick cookware? A perfluorinated chemical that causes cancer in rats. (See story below).
Upholstered furniture, mattresses, carpets, even the plastic casings around the computer and television may contain brominated flame retardants. The good news is that they slow the spread of fire. The bad news is they likely contain polybrominated diphenyl ethers (PBDEs). In rat studies, they interfered with thyroid function, affected behaviour and caused liver tumours. PBDEs have been found in house dust and human breast milk.
Absorbed by a woman, many chemicals can be passed on to her children through breast milk and through the placenta.
A U.S. study of umbilical cord blood from 10 newborns found pesticides, chemicals used in consumer products, and by-products from gasoline, garbage and the burning of coal. The newborns averaged 200 contaminants, many of them carcinogens, developmental toxins and neurotoxins.
“It’s a big red flag,” says Jane Houlihan, vice president of research at the Environmental Working Group in Washington, D.C., which spearheaded the study. “Babies aren’t supposed to be born pre-polluted.”
While most experts agree there’s no safe exposure level to carcinogens, it’s generally believed that other chemicals have threshold doses. Below that amount, harmful effects are unlikely. But above it, usually in large doses, exposure may be risky.
At least that’s the conventional wisdom. Medical epidemiologist Wigle wonders if perhaps our tests are not yet sophisticated enough to pick up subtle effects.
But even with a safe threshold, there’s not a simple formula. Some chemicals are quickly excreted, while others persist and accumulate. There’s the individual factor. “Everyone has different susceptibilities, driven by their genetics,” says Houlihan. And the timing of exposure counts. Humans are more vulnerable in the womb and during early childhood and puberty.
And there’s the great unknown variable: the synergy of the soup. Could the sum of all the synthetic chemicals in our bodies be more toxic than the parts? “That’s extremely important and largely unresolved,” says Wigle.
Researchers eager to know the health effects of this body burden look at illnesses that are on the upswing. The worldwide prevalence of asthma is rising by 50 per cent, on average, every decade. From the early 1970s to 2002, according to the Public Health Agency of Canada, the age-standardized incidence of testicular cancer was up 54 per cent, breast cancer 19 per cent, thyroid cancer 221 per cent, and non-Hodgkin’s lymphoma (a cancer of the lymphatic system) 83 per cent.
“We know our genetics haven’t changed,” says Houlihan. “With rapid changes in health, scientists suspect environmental exposures play a role.”
At the University of Ottawa, assistant health sciences professor Karen Phillips is part of a group examining chemicals known as hormone disruptors or endocrine toxins, which interfere with hormone pathways. Human health effects may include fertility problems, reproductive cancers and birth defects, especially abnormal formation of the male urogenitals.
While some of these diseases and disorders have shown up in animal studies, says Phillips, it’s been at very high doses, more than the average person would experience. The reproductive physiologist says the incidence of diseases associated with hormone disruptors could be explained in humans by other factors, such as improved screening techniques and rising rates of obesity.
She did, however, point to Denmark, where young men have experienced an increase in testicular cancer, lower sperm counts and birth defects such as cryptorchidism, or undescended testicles, and hypospadias, where the penis opening is located somewhere other than the tip.
“There could be an environmental factor at play,” she speculates, but adds that more evidence is needed.
The government will start collecting some next year. As part of the Canadian Health Measures Survey of 5,000 volunteers, biomonitoring tests will be conducted for about 60 chemicals and heavy metals. It’s Canada’s first large scale national testing for environmental contaminants, says Rene Langlois, chief survey developer. It will provide a baseline look at Canadians’ body burden and enable researchers to track trends over time.
But environmentalists want more from Ottawa, and the Canadian Environmental Protection Act is up for review. Smith from Environmental Defence would like to see timelines for the elimination of the most harmful chemicals and more attention paid to the Great Lakes basin, a pollution hotspot.
He and other advocates believe that chemical manufacturers are not held to a high enough safety testing standard. They point to the European Union’s REACH (Registration, Evaluation and Authorisation of CHemicals) proposal, which could be signed early next year. REACH would shift the burden of proof for safety from government to industry and include strong incentives to replace toxic chemicals with safe substitutes.
“It’s a paradigm shift in the way chemicals are managed and controlled,” says Beverly Thorpe, director of Clean Production Action in Montreal, a non-profit group that promotes “green” chemistry.
Allan Godfrey, manager of the toxic substances management division at Health Canada, does not agree that this country is lagging behind. Canada has temporarily banned four fluorinated polymers that are precursors to the controversial perfluorinated carboxylic acids, or PFCAs, for example.
Since 1987, new substances have undergone a government-led risk assessment before being used. There’s about 600 to 800 new substances each year, says Godfrey.
The government is currently categorizing some 23,000 older, unassessed chemicals to single out ones requiring further investigation. The report, due this September, is likely to list about 5,000 substances needing more action.
“Our categorizing (of these chemicals) is world leading,” he says. “I don’t know another country that’s done it.”
Some people, impatient with government and science, are taking action themselves. Toxic Nation volunteer Mary Sexton from St. John’s was shocked when she saw her results: She had 49 out of 88 chemicals. She tested positive for 31 suspected carcinogens. “It was an awakening for me,” says the 43-year-old television producer.
She now avidly reads ingredient labels, drinks only bottled water, keeps her house cleaner, uses biodegradable cleansers and detergents and diligently gets her breast exams and Pap smears. Already a vegetarian, she’s bumped up her diet to 70 per cent organic. She’s given up her daily six cups of coffee – worried about contaminants – and thrown out her non-stick frying pan.
She has no idea how much any of these changes will help. She does, after all, live in a toxic world.
“If you’re a walking, breathing Canadian,” says Sexton, “you’re polluted.”