Tradition versus toxicants: are new arrivals to Canada at risk?

Researchers examine link between Asian Canadian cultural traditions and exposure to mercury, lead and cadmium.

Many people are familiar with toxins—the potentially harmful products found in nature, such as snake venom or poisonous mushrooms. Less might be familiar with toxicants, the man-made products introduced to the environment through human activity. 

As an environmental health expert, Vancouver Coastal Health Research Institute scientist Dr. Tom Kosatsky knows the risks of exposure to toxicants like lead, mercury and cadmium. During pregnancy, these toxicants can cause neurological damage to babies. While Health Canada regularly surveys the levels of toxicant exposure across Canada, Kosatsky says one sub-group of Canadians—newly arrived South and East Asian women—is underreported, often due to language and cultural barriers. 

To make sure they weren’t ignoring any health problems, Kosatsky and his colleagues set out to study newly arrived immigrant women from South and East Asia.

“We had a theory that these women might be more exposed to toxicants than other Canadians from products and traditional lifestyles that might put them at risk. But we had to find a way to reach them.” 

Kosatsky’s team had to think outside the box for ways to recruit women in the Lower Mainland who aren’t yet part of mainstream Canadian society.  “We went through health clinics, community groups, immigrant aid groups and religious groups. We ran ads in Punjabi, Cantonese, and Mandarin newspapers, on radio stations, on buses and even in movie theatres. And then we built by word of mouth. It really paid off. There would have been no sample otherwise.”

Once Kosatsky had gathered a sample group of 164 women, from countries including India, China and Taiwan, he tested their blood levels of mercury, lead and cadmium and their links to common exposure sources. These sources include:

  • traditional South Asian cosmetics like kohl and sindoor, both of which can contain lead and cadmium
  • traditional medicines such as Ayurvedic (from the Indian subcontinent) remedies and traditional Chinese medicines
  • dental fillings, which can contain mercury
  • mercury-laden fish like swordfish, shark, king mackerel and tuna (other than canned light tuna)

The findings? Levels of all three toxicants were slightly higher in these women than in other Canadian women. But, Kosatsky says, the levels were not high enough to warrant any urgent changes.

“We would say women of childbearing years in these communities should pay more attention to seafood consumption and monitor their exposure to some of the cosmetics that contain toxicants. But we don’t think any large-scale behaviour changes are needed.”

Kosatsky, who is also the medical director for Environmental Health Services at the British Columbia Center for Disease Control and a clinical professor in the Department of Medicine at the University of British Columbia, says his job is to ensure people’s health is protected, not to suggest cultural or traditional changes, unless women have specific health concerns they want addressed.

It’s important to balance the benefits of maintaining cultural ties and traditions against any possible negative side effects.

Kosatsky says Health Canada does all it can to regulate products containing lead, cadmium and mercury. But it’s difficult to catch everything when so many products are coming in to the country.

Adapting to diversity

The study results will be shared with clinicians and care-providers throughout the Lower Mainland. Dr. James Lu, medical health officer lead for Environmental Health, Vancouver Coastal Health, is helping to get the word out. Lu says while there are no urgent interventions required, the study is an important reminder to get conversations started with these communities.

“Our population demographics are changing. We have people coming here from all over the world. As health care providers we need to recognize that their needs and exposures are different than what we are used to, and we have to adapt to meet them.” 

Lu says he’s already met with pre- and perinatal care providers to discuss the study results and talk about ways to help women make healthier choices when it comes to fish consumption. East Asian women are most at risk when it comes to mercury exposure.
Both Lu and Kosatsky want to build on the outreach and recruitment strategies that were so successful with this project. “We can’t just rely on the health network to reach these populations. If we can document how different recruitment approaches work it will pay off for other studies going forward.” Kosatsky is already planning to use the connections made with this study to further research in cardiovascular health. 


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