Two years ago, people from the Aamjiwnaang First Nation near Sarnia noticed something strange—they had three girls’ softball teams but only one boys’ team. The people of this Chippewa community on the St Clair River had suspected for some time that they had fewer male births, but this hit it home.

Ada Lockridge, an environmental activist from Aamjiwnaang, noticed the lack of boys herself; she and her two sisters had eight daughters and one son between them. She pored over her band’s birth registry and tracked the changes over time. In 1984 the birth rates were relatively balanced. But in 1993, slightly more girls were born than boys, and by 2002 the birth rate for girls had jumped to twice that of boys.

The story made it into both the local papers and The Globe and Mail. The Aamjiwnaang reservation is surrounded by petrochemical plants that bought the land from them in the 1960s. There was speculation that chemicals from the surrounding factories had caused the men (because sperm, not eggs, determine the sex of a baby) to father more daughters.

Many different kinds of chemicals, known as endocrine disruptors (popularly called ‘gender benders’) can act as hormones and distort the body’s chemical balance. A variety of endocrine disruptors are released by chemical processing, including many created by petrochemical refining. In the case of Aamjiwnaang, scientists and industry representatives argued that the difference could simply be a statistical fluke, as only 850 or so people lived on the reservation.

Constanze A. Mackenzie, a professional in wildlife toxicology, analysed the data. She found that the decline in male births— which occurred gradually—was statistically significant. Her findings were published (with Ada Lockridge and Margaret Keith as co-authors) in the October 2005 issue of Environmental Health Perspectives (EHP), the scientific peer-reviewed journal of the US Department of Health and Human Services’ National Institute of Environmental Health Sciences.

Other parts of the world have also seen the same trend, such as Seveso, Italy, after a 1976 explosion at a herbicide factory that released a cloud of dioxins (toxic chemical by-products that mimic estrogen).
But the Aamjiwnaang reservation had not experienced any single large catastrophe. “If a community can be affected by environmental contaminants [such] that their reproduction is affected to such a significant degree, this could mean that low-level exposures could also have an effect on populations,” says Mackenzie.

Currently, there are other health problems that plague the reservation. Women often suffer from multiple miscarriages, “as many as six in a row,” says Lockridge. Asthma is practically the norm in young people, and it is extremely common for children to have chronic ear infections, an affliction that plagues many of Canada’s First Nation’s communities. “I realized my one-year-old daughter had an ear infection when she started slamming her head against the wall,” says Lockridge. “She had to have tubes inserted into her ears for a year.”

Lockridge is certain of what is to blame: “We never knew that these problems could have been because of the factories, nobody told us. We thought it just ran in the family. But after I started finding out about all of this, all the chemicals they release and what they can do to you, I was crying all the time. Now I’m just angry,” she said.

Most people in Canada, like the residents of Aamjiwnaang, are not exposed to large amounts of one single chemical; rather, we are all exposed to small amounts of hundreds (even thousands) of different chemicals every day. Many of these are detrimental to our lungs, often toxic or carcinogenic, and some can mimic hormones.

And many of these chemicals are becoming more abundant in our surroundings. In some respects, industrial pollution in Canada hasn’t been getting better—it’s been getting worse.

We Canadians often consider ourselves world leaders in a green economy. Our forests have grown over the past few years. Compared to levels in the 1970s, our air contains much less sulphur dioxide and lead. Our lakes and rivers contain far less of certain pollutants than those in other countries.