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Mercury in Canadians

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Organization: Health Canada

Date published: 2021-12-14

Information on human biomonitoring of mercury in Canada with results from the Canadian Health Measures Survey.

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Background

What is mercury?

Mercury (CASRN 7439-97-6) is a naturally occurring metal that is liquid at room temperature. It exists in elemental, inorganic and organic forms and enters the environment through both natural and industrial processes. Mercury persists in the environment and can accumulate over time.

Where is mercury found?

Mercury is present in the environment, even in remote Arctic regions, because it is persistent, mobile and tends to accumulate in colder climates. Canada prohibits the manufacture and import of most mercury-containing products. However, certain essential products are exempt, such as dental amalgams and fluorescent lamps. Mercury is also found in certain foods, such as fish.

How are people exposed to mercury?

Mercury exposure in the general population is mainly through eating larger species of fish. Organic methylmercury is the primary form of exposure in that case. In Arctic communities, eating marine mammals is a major source of mercury. To a lesser extent, the general population is exposed to inorganic mercury from dental amalgams.

How is mercury measured in people?

Mercury is absorbed into the bloodstream after being ingested or inhaled. Mercury in urine is commonly measured to evaluate long-term exposure to its elemental and inorganic forms. Mercury concentrations in blood reflect recent dietary exposure to organic forms, particularly methylmercury.

What are the potential health impacts of mercury?

Exposure to organic mercury may cause neurological effects, including developmental neurotoxicity in fetuses and children. Inhaling mercury vapour may cause respiratory, cardiovascular, kidney and neurological effects. The International Agency for Research on Cancer has classified methylmercury compounds as possibly carcinogenic to humans.

What is the Government of Canada doing to lower human exposures to mercury?

Mercury is identified as toxic under the Canadian Environmental Protection Act, 1999. Mercury is subject to numerous federal risk management initiatives in Canada directed toward industrial releases. The Products Containing Mercury Regulations prohibit the manufacture and import of most mercury-containing products in Canada. However, there are exemptions for a few essential products, such as fluorescent lamps, which are subject to mercury content limits. In addition, regulations under the Canada Consumer Product Safety Act limit the amount of mercury in surface-coating materials. Health Canada has established a methylmercury blood guidance value of 20 µg/L for the general adult population. For children, pregnant women and women of child-bearing age, the provisional methylmercury blood guidance value is 8 µg/L. Health Canada has also established maximum levels for mercury in fish sold to consumers. Guidelines are in place for mercury in Canadian drinking water. The Government of Canada continues to monitor and assess mercury.

Data sources

Table 1. Biomonitoring initiatives and their target populations
Initiative Target population
Canadian Health Measures Survey (CHMS) General Canadian population living in the 10 provinces
First Nations Biomonitoring Initiative (FNBI) First Nations people living on-reserve south of the 60° parallel
Maternal-Infant Research on Environmental Chemicals (MIREC) study Pregnant women and their infants recruited from obstetric and prenatal clinics in 10 cities across Canada
International Polar Year Inuit Health Survey (IPY IHS) Inuit populations from the Inuvialuit Settlement Region (ISR), Nunavut and Nunatsiavut
U.S. National Health and Nutrition Examination Survey (NHANES) General U.S. population

This fact sheet presents nationally representative data from the CHMS. These data are compared with data from the FNBI, the MIREC study, the IPY IHS and the U.S. NHANES.

Table 2. Biomonitoring initiatives and their collection periods, participant age ranges, matrices sampled and biomarkers measured
Collection period Age range (years) Matrix Biomarker
CHMS
2007–2009 6 to 79 Blood Total mercury
2009–2011 3 to 79 Blood Total mercury
2012–2013 3 to 79 Blood Total mercury
2014–2015 3 to 79 Blood Total mercury
2016–2017 3 to 79 Blood Total mercury
2018–2019 3 to 79 Blood Total mercury
FNBI
2011 20+ Blood Total mercury
MIREC study
2008–2011 18+ Blood Total mercury
IPY IHS
2007–2008 18+ Blood Total mercury
U.S. NHANES
2007–2008 1+ Blood Total mercury
2009–2010 1+ Blood Total mercury
2011–2012 1+ Blood Total mercury
2013–2014 1+ Blood Total mercury
2015–2016 1+ Blood Total mercury

Results

Canadian population

Figure 1. Mercury concentrations in the Canadian population aged 20 to 79.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in the Canadian population from the CHMS (2007–2019).

Figure 1: Text description
Collection period Geometric mean
2007–2009 0.88
2009–2011 0.92
2012–2013 0.92
2014–2015 0.70
2016–2017 0.76
2018–2019 0.85

Concentrations of mercury were relatively unchanged in the Canadian population from 2007–2019. There was no statistically significant change over time (P = 0.132).

Canadian population, by age group

Figure 2. Mercury concentrations in the Canadian population, by age group.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in the Canadian population by age group from the CHMS (2007–2019). Geometric mean mercury concentrations could not be calculated for individuals under 20 years old. This was because too many samples were below the analytical limit of detection.

Figure 2: Text description
Collection period Age group (years) Geometric mean
2007–2009 20 to 39 0.72
2007–2009 40 to 59 1.0
2007–2009 60 to 79 0.92
2009–2011 20 to 39 0.71
2009–2011 40 to 59 1.0
2009–2011 60 to 79 1.2
2012–2013 20 to 39 0.82
2012–2013 40 to 59 0.96
2012–2013 60 to 79 1.0
2014–2015 20 to 39 0.55
2014–2015 40 to 59 0.77
2014–2015 60 to 79 0.88
2016–2017 20 to 39 0.61
2016–2017 40 to 59 0.88
2016–2017 60 to 79 0.84
2018–2019 20 to 39 0.78
2018–2019 40 to 59 0.84
2018–2019 60 to 79 0.98

Concentrations of mercury were similar across age groups in the Canadian population.

Canadian population, by sex

Figure 3. Mercury concentrations in the Canadian population aged 20 to 79, by sex.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in the Canadian population by sex from the CHMS (2007–2019).

Figure 3: Text description
Collection period Sex Geometric mean
2007–2009 Females 0.87
2007–2009 Males 0.90
2009–2011 Females 0.86
2009–2011 Males 0.99
2012–2013 Females 0.94
2012–2013 Males 0.90
2014–2015 Females 0.68
2014–2015 Males 0.73
2016–2017 Females 0.79
2016–2017 Males 0.73
2018–2019 Females 0.83
2018–2019 Males 0.87

Concentrations of mercury were similar between females and males in the Canadian population.

Comparison of the general population and First Nations on-reserve population in Canada

Figure 4. Mercury concentrations in the general population and First Nations on-reserve population in Canada.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in the general population aged 20 to 79 from the CHMS (2009–2011) and in the First Nations on-reserve population aged 20 and older from the FNBI (2011).

Figure 4: Text description
Biomonitoring initiative Geometric mean
CHMS 0.87
FNBI 0.95

Concentrations of mercury were similar between the general population and First Nations on-reserve population in Canada.

Comparison of women of child-bearing age and pregnant women in Canada

Figure 5. Mercury concentrations in women of child-bearing age and women in the first or third trimester of pregnancy in Canada.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) for women of child-bearing age (18 to 49) in the general population from the CHMS (2009–2011) and for women in the first or third trimester of pregnancy from the MIREC study (2008–2011).

Figure 5: Text description
Biomonitoring initiative Geometric mean
CHMS 0.67
MIREC study (1st trimester) 0.61
MIREC study (3rd trimester) 0.50

Concentrations of mercury were similar between women of child-bearing age and women in the first or third trimester of pregnancy in cities across Canada.

Comparison of the general population and Inuit populations in Canada

Figure 6. Mercury concentrations in the general population and Inuit populations in Canada, by sex.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in females and males in the general population aged 18 to 79 from the CHMS (2007–2009) and in Inuit populations aged 18 and older in the ISR, Nunavut and Nunatsiavut from the IPY IHS (2007–2008).

Figure 6: Text description
Biomonitoring initiative Sex Geometric mean
CHMS Females 0.81
CHMS Males 0.82
IHS (ISR) Females 4.1
IHS (ISR) Males 5.6
IHS (Nunavut) Females 7.9
IHS (Nunavut) Males 9.4
IHS (Nunatsiavut) Females 2.8
IHS (Nunatsiavut) Males 4.2

Concentrations of mercury were higher in Inuit populations in the ISR, Nunavut and Nunatsiavut than in the general population in Canada.

Comparison of the Canadian and U.S. populations

Figure 7. Mercury concentrations in the Canadian and U.S. populations.

This figure shows the geometric mean concentrations of mercury in blood (µg/L) in the Canadian population from the CHMS (2007–2019) and in the U.S. population from the NHANES (2007–2016). Note that there are slight differences between the surveys in sampling (such as the age ranges of participants) and analysis (such as the limits of detection).

Figure 7: Text description
Biomonitoring initiative Collection period Geometric mean
CHMS 2007–2009 0.88
CHMS 2009–2011 0.92
CHMS 2012–2013 0.92
CHMS 2014–2015 0.70
CHMS 2016–2017 0.76
CHMS 2018–2019 0.85
NHANES 2007–2008 0.94
NHANES 2009–2010 1.0
NHANES 2011–2012 0.86
NHANES 2013–2014 0.81
NHANES 2015–2016 0.81

Concentrations of mercury were similar between the Canadian and U.S. populations.

Suggested citation

Health Canada. 2021. Mercury in Canadians. Ottawa, ON. Available: https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/environmental-contaminants/human-biomonitoring-resources/mercury-canadians.html

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