Levels of Human Exposure to Harmful Substances

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The Levels of Human Exposure to Harmful Substances indicator presents the concentrations of select environmental chemicals in the Canadian population from Cycle 1 (2007–2009), Cycle 2 (2009–2011) and Cycle 3 (2012–2013) of the Canadian Health Measures Survey (CHMS). The indicator includes cadmium, lead and mercury in blood and bisphenol A (BPA) in urine for participants aged 6 to 79 years, as well as the concentration of 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) and perfluorooctane sulfonate (PFOS) in blood plasma for participants aged 20 to 79 years. These results are important to monitoring chemical exposure and to track trends in Canadians over time.

The CHMS is a cross-sectional survey started in 2007 to address important data gaps and limitations in existing health information in Canada. Its principal objective is to collect national-level data on important indicators of Canadians' health status, including those pertaining to exposures to environmental chemicals. The CHMS examined 48 environmental chemicals in Cycle 3. The biomonitoring data aids the government in assessing human exposure to environmental chemicals and in developing policies to reduce exposure to toxic chemicals.

Some chemicals may be present and detectable in a person without causing an adverse health effect. Detection of a chemical indicates that an exposure has occurred. However, biomonitoring alone cannot predict the health effects, if any, that may result from exposures. Factors such as age, health status, the dose, the duration, frequency and timing of exposures, along with the toxicity of the chemical must be considered to predict whether adverse health effects may occur.

Geometric mean concentrations of selected substances in blood, blood plasma or urine, Canada, 2007 to 2013
Survey yearsCadmium
Blood
(µg/L)
Lead
Blood
(µg/L)
Mercury
Blood
(µg/L)
BPA
Urine
(µg/L)
PBDE-47
Blood plasma
(µg/L)
PFOS
Blood plasma
(µg/L)
2007–20090.34130.691.20.068.9
2009–20110.31120.711.2n/a6.9
2012–20130.34110.811.1n/an/a

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How this indicator was calculated

Note: Mercury is shown as total mercury (organic and inorganic). Concentrations of total blood mercury differs between cycles in part due to changes in the limit of detection (LOD) from 0.1 µg/L in Cycle 1 and 2 to 0.4 µg/L in Cycle 3. The concentrations of cadmium, lead and mercury in blood and bisphenol A (BPA) are from participants aged 6 to 79 years, while the concentrations of 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) and pefluorooctane sulfonate (PFOS) in blood plasma are from participants aged 20 to 79 years. The selection of environmental chemicals varies between cycles. n/a means that the data is not currently available for those survey years and µg/L means microgram per litre. For more information, refer to the Data Sources and Methods document.
Source: For cadmium, lead, mercury and BPA: Health Canada (2015) Third Report on Human Biomonitoring of Environmental Chemicals in Canada: Results of the Canadian Health Measures Survey Cycle 3 (2012–2013). For PFOS: Health Canada (2013) Second Report on Human Biomonitoring of Environmental Chemicals: Results of the Canadian Health Measures Survey Cycle 2 (2009–2011). For PBDE-47: Health Canada (2010) Report on Human Biomonitoring of Environmental Chemicals in Canada: Results of the Canadian Health Measures Survey Cycle 1 (2007–2009).

Biomonitoring cannot tell us the source, or route, of exposure. The amount of chemical measured in a person's blood, urine or blood plasma is representative of the total amount that is present in the body at a given time, from all sources (air, water, soil, food, and consumer products) and all routes of exposure (ingestion, inhalation, skin contact).

Cadmium: Cadmium is a naturally occurring metal used in batteries and in electroplating to protect other metals from corrosion. It may be emitted directly to air from human activities such as non-ferrous smelting and refining, and fuel consumption for electricity generation or heating. Inhalation of cigarette smoke is the major source of cadmium exposure in smokers. Non-smokers are primarily exposed to cadmium through food, although occupational exposure can also be a source. Other minor sources of exposure include drinking water, soil or dust, while other minor exposure pathways may include inhalation and releases from consumer products. Cadmium and its compounds have been classified as probably carcinogenic to humans by inhalation by Environment and Climate Change Canada and Health Canada. Inorganic cadmium compounds are listed on Schedule 1, List of Toxic Substances, under the Canadian Environmental Protection Act, 1999 (CEPA 1999).

Lead: Lead is a naturally occurring element found in rock and soil. It is currently used in the refining and manufacturing of products such as lead acid car batteries, lead shot and fishing weights, sheet lead, solder, some brass and bronze products, pipes, paints (other than paints for use by children) and some ceramic glazes. Exposure to trace amounts of lead occurs through soil, household dust, food, drinking water, and air, due to lead's natural abundance in the environment and its widespread use for much of the twentieth century. Lead exposure in Canada has decreased substantially since the early 1970s, mainly because leaded gasoline was phased out; the use of lead in consumer paints and other coatings on children's products have been restricted by regulations; and the use of lead solder in food cans was eliminated. Current potential sources of lead exposure may include ingestion of chips from lead-based paints on interior and exterior surfaces of older buildings; ingestion of lead-contaminated household dust; ingestion of water from drinking water distribution systems containing lead pipes, lead plumbing fittings, or lead-based solder; ingestion of food grown in areas with high levels of lead in air, water or soil (e.g., near base metal smelters, combustion sources or roads, or in cities); use of ceramic or glass foodware with lead-containing glazes; and mouthing of consumer products containing lead. Housing renovations and hobbies, including stained-glass making, can also increase exposure to lead. Lead is considered a cumulative general poison. Very high exposure may result in vomiting, diarrhea, convulsions, coma and death. Chronic exposure to relatively low levels may affect the central and peripheral nervous systems, blood pressure, renal functioning and result in reproductive problems and developmental neurotoxicity. Lead is listed on Schedule 1, List of Toxic Substances, under CEPA 1999.

Mercury: Mercury is a naturally occurring metal but is widespread in the environment due to many industrial processes (e.g., chemical manufacturing operations and coal combustion). The general population is exposed to primarily methylmercury through consuming contaminated fish and seafood. To a much lesser extent, the general population is also exposed to inorganic mercury from sources such as dental amalgams and broken mercury-containing lamps. Mercury is toxic to humans. The human health effects depend on different factors, such as the form of mercury encountered, the amount, length of exposure and the age of the person. For example, oral exposure to organic mercury compounds can cause neurological effects and developmental neurotoxicity. The exposure of a fetus or young child to organic mercury can affect the development of the nervous system, including fine-motor function, attention, verbal learning and memory. Mercury is listed on Schedule 1, List of Toxic Substances, under CEPA 1999.

BPA: BPA is a synthetic chemical used in plastics, epoxy resins and thermal paper. The main route of exposure to BPA for the general public is through dietary intake through various sources, including food packaging and repeat-use plastic containers. Exposure can also occur from ambient and indoor air, drinking water, soil, and dust, and from the use of consumer products. BPA is toxic to human health and is listed on Schedule 1, List of Toxic Substances, under CEPA 1999.

PBDEs: PBDEs are a synthetic chemical used to produce fire retardants. The public may be exposed to PBDEs in food (mostly fish, dairy products and meat), drinking water, soil and air. Food represents the principal source of exposure to PBDEs for the majority of age groups. Health Canada concluded that exposure to PBDEs used in consumer products, via inhalation, dermal contact with dust, or oral contact with household products treated with flame retardants is negligible in comparison with intake from food. PBDEs have a harmful effect on the environment and polybrominated biphenyls are classified as a possible human carcinogen by the International Agency for Research on Cancer. PBDE-47 is listed on Schedule 1, List of Toxic Substances, under CEPA 1999.

PFOS: Perfluorinated compounds are produced for industrial and commercial uses, such as stain/water/oil-repellent fabric protectors, in water/oil-repellent paper coatings, wiper blades, bike chain lubricant, wire and cable insulation, pharmaceutical packaging, food packaging, engine oil additives, nail polish, hair-curling and straightening products, metal plating and cleaning, fire retardant foams, inks and varnishes. For the general public, exposure is widespread through food, drinking water, consumer products, dust, soil and air. Generally, ingestion of food, drinking water and house dust are expected to be the main routes of exposure for adults in the general population whereas oral hand-to-mouth contact with consumer products, such as carpets, clothing and upholstery, is a significant contributor for infants, toddlers and children. No definitive links between exposure to these substances and human health effects have been established; however, adverse effects have been observed in animals, including developmental toxicity and carcinogenicity. PFOS is listed on Schedule 1, List of Toxic Substances, under CEPA 1999.

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This indicator is used to measure progress towards Target 4.8: Chemical Management – Reduce risks to Canadians and impacts on the environment and human health posed by releases of harmful substances of the Federal Sustainable Development Strategy 2013–2016.

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