The Threat Of Chemical Exposure In Canada

We live in a chemical world where we are in contact with chemicals daily. In Canada, over 23, 000 chemicals are registered for use with approximately 300 new substances being added annually. Contamination occurs because of commercial, industrial and individual pollution of the land, air and water with extensive quantities of toxic chemicals and the mismanagement of the government in failing to address the release and disposal of chemical toxins.

Population exposures to toxic chemicals vary from country to country and within countries. The variations found in populations within countries is often the work of many factors at play and one such factor is socioeconomic status. Socio-economic status (SES) is an important social determinant of health that encompasses income, educational attainment, financial security, housing and one’s subjective perception of social class and status. By encompassing such, socio-economic status is often considered a gradient and has important considerations in environmental health and can aid in explaining the inequities present in the distribution of toxic exposures. Both ends of the spectrum, low SES and high SES populations are more susceptible to specific contaminants. For example, low-income individuals are more likely to be exposed to BPA a plasticiser and certain phthalates which are commonly found in personal care products and cheap plastics.

Another common association amongst low-income SES is levels of lead and cadmium absorption. On the other hand, high-income individuals are more likely to consume expensive fish such as tuna, marline and swordfish which Environmental toxicologists claim have high levels of heavy metals. This would explain the disproportionate levels of mercury, thallium and arsenic that characterizes this population. An increasing number of studies are finding that communities of lower socioeconomic status tend to be exposed more frequently to higher levels of toxins and pollutants.

First Nation communities are such communities; characterized by high infant mortality, chronic and infection disease, unemployment, poor housing, and extreme poverty, First Nations are particularly vulnerable to toxic substances. The disparities amongst First Nations in Canada is vastly extensive that despite being a developed country, the health of our First Nations is comparable to that of third-world countries. That being said, because First Nation communities in the past have enjoyed very little status and power, their interests have frequently been compromised in regards to industrial development projects such as petroleum extraction, mining, forestry and pulp and paper manufacturing.

Majority of First Nation communities are within proximity of industries and other sources of pollution, and many of the community members find employment in these industrial settings, both of which facilitate exposure levels. Whereas affluent and politically connected communities can successfully defy a prejudicial development, marginalized communities such as First Nation communities cannot, thus they are more susceptible to finding toxic landfills popping up in their communities. For example, Ojibwa communities located near the Wabigoon River in Northern Ontario, their staple item of food, fish, was compromised as a result of the methyl mercury contamination which disrupted the lakes ecosystem costing the community subsistence and income.

The consumption of wild game, fish and marine mammals has nutritional, spiritual and cultural significance to the members of First Nation communities, but these food sources because of bioaccumulation and biomagnification, are more likely to have higher concentrations of mercury and other organic pollutants such as pesticides, PBDEs and PCBs. First Nations are highly integrated and dependent on the land for food, income and it is an important part of their culture, that when their land becomes contaminated it has severe detrimental effects on the community. Moreover, according to the Treasury Board of Canada Secretariat, Canada currently has 23, 313 contaminated sites of which Ontario houses the most number of contaminated sites of 3, 772. Of these sites, there are 252 sites that are classified as High Priority for Action and Image 1 shows a snapshot of the top 10 sites.

When the location of these sites is considered all of them fall within a First Nations community/ reserve. For example, Kitchenuhmaykoosib Inninuwug is an Oji-Cree First Nation reserve located in Northwestern Ontario and the individuals of this reserve are within a kilometer exposure radius to soil and groundwater PHCs (petroleum hydrocarbons), and PAHs (polycyclic aromatic hydrocarbons). Another community is the Tyendinaga Mohawks who are the Mohawk First Nations located on the Bay of Quinte and they are within a kilometer exposure radius to soil PHCs, BTEXs (benzene, toluene, ethylbenzene, and xylene), and metal, metalloid and organometallic. Lastly, of the First Nation communities, infants, pregnant and breastfeeding women and Elders are particularly at risk for contamination.

Aside from First Nations, individuals of low SES are more likely to live in deprived urban communities which have a greater exposure to lead, air pollutants, water contaminants such as DBPs (disinfection by-products), arsenic and nitrates. These low-income neighborhoods are often adjacent to industrial areas, sites used previously for toxic waste disposal such as smelters, and high-density traffic interchanges and corridors. Housing in these neighborhoods are often faulty in design, poorly maintained and run down which contribute to hazardous air quality amplified by mold growth, lead paint or asbestos. Often the carpets and furnishings in these low-income households’ act as reservoirs for lead, pesticides and other toxic chemicals. Moreover, these low-income neighborhoods, frequently fail to meet the national ambient air quality standards for particulate matter and for acceptable levels of polycyclic aromatic hydrocarbons (PAHs).

Exposures to PAHs are particularly high amongst urban, minority (Black, non-Hispanic and Hispanic/Mexican) and low-income populations. It is also very common to find lead service lines in these low-income districts which consequently exposes drinking water to potential lead. Other sources of common lead exposure include food grown in lead-contaminated soil, lead-based paint, pica, lead dust and toys. Children of low-income neighborhoods are particularly vulnerable to lead toxicity which is evident through their higher blood lead levels. For example, a study found blood lead levels in children from South Riverdale, a neighborhood in southern Toronto characterized by socioeconomic homes of lower status were significantly higher, above Canada’s guidance value of 10 µg/dL, compared to the rest of Ontario. The soil contained 500 ppm lead which surpasses the acceptable Ontario Ministry of the Environment residential guidelines of 200 ppm. Children are particularly susceptible as a result of their oral exploratory behaviour which facilitates the transfer of lead from the environment into the bodies of children. Moreover, urban children are also highly exposed to benzene, a carcinogen as a result of increased exposure to environmental tobacco smoke and gasoline exhaust from cars.