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This overview is a companion piece to the Third Report on Human Biomonitoring of Environmental Chemicals in Canada. It provides context for the Report as well as some background information on biomonitoring.
Chemical substances are everywhere - in air, soil, water, products, and food - and can enter the body through ingestion, inhalation, and skin contact. The Government of Canada uses a variety of methods, tools, and models to assess human exposure to chemicals (both natural and synthetic) and the potential effects that these exposures may have on human health. Human exposure to chemicals can be estimated indirectly by measuring chemicals in the environment, food, or products, or directly in the human body using biomonitoring (see Figure 1).
Biomonitoring information for Canadians is collected on an ongoing basis through the Canadian Health Measures Survey (CHMS). To date, three cycles of the CHMS have been completed, the first cycle conducted in 2007-2009, the second cycle in 2009-2011, and the third cycle in 2012-2013. Health Canada's Third Report on Human Biomonitoring of Environmental Chemicals in Canada presents national biomonitoring data on the Canadian population's exposure to chemicals, collected as part of the CHMS. The Third Report provides information to scientists, health professionals, and policy makers on the levels of chemicals in Canadians. These measures are an important starting point for monitoring and research related to chemical exposure and to track trends in levels of chemicals in Canadians over time.
Biomonitoring is the measurement, in people, of a chemical or the products a chemical makes when it breaks down. This measurement (called the level or concentration) is usually taken in blood and urine and sometimes in other tissues and fluids such as hair, nails, and breast milk. The measurement indicates how much of a chemical is present in a person.
The Canadian Health Measures Survey (CHMS), led by Statistics Canada in partnership with Health Canada and the Public Health Agency of Canada, is the most comprehensive, direct health measures survey conducted in Canada. The survey is designed to represent the Canadian population. It collects information on the general health and lifestyles of Canadians through interviews and direct physical measurements (for example, weight and height) and provides information on chronic and infectious disease, physical fitness, nutrition, and other factors that influence health. The CHMS also includes a biomonitoring component, in which blood and urine samples are collected to provide information on exposure to chemicals.
The first Report on Human Biomonitoring of Environmental Chemicals in Canada was published in August 2010 with baseline data for 92 chemicals measured in Canadians aged 6 to 79 years at 15 sites across the country during the first cycle of the CHMS (2007-2009).
The Second Report on Human Biomonitoring of Environmental Chemicals in Canada was published in April 2013 with data for 91 environmental chemicals, 42 of which were also measured in cycle 1. Data for cycle 2 of the CHMS (2009-2011) were collected from 6,400 Canadians between the ages of 3 and 79 years at 18 sites across the country.
The third cycle of the CHMS included 5,800 Canadians between the ages of 3 and 79 years at 16 sites across Canada. Cycle 3 included 48 environmental chemicals measured in individual samples, 33 of which have been measured in previous cycles. Collection for the third cycle of the CHMS took place between January 2012 and December 2013. Planning for future cycles is underway.
The Third Report on Human Biomonitoring of Environmental Chemicals in Canada provides the results of the biomonitoring component from the third cycle of the CHMS (2012-2013). The primary purpose of the Third Report is to provide chemical exposure information, based on human biomonitoring, to scientists, health professionals, and policy makers. This information will help with the evaluation of chemical exposure and the development of policies to protect the health of Canadians.
The Third Report describes the survey methods used and includes the following information for each chemical or chemical group:
The Third Report provides biomonitoring results, presented in tables, representing the total Canadian population, further sub-divided by sex and age group. The data tables indicate how many samples were included and the average concentration (or level) of the chemical in the blood or urine of that group, as well as its percentile. A percentile provides an idea of how the measurements are distributed in the population. For example, if a measured concentration is at the 95th percentile, then 95% of the people measured are below this concentration and 5% of people are above it.
For chemicals that were measured in cycle 3 as well as in cycle 1 and/or cycle 2, all sets of data are shown for comparison. Data for chemicals measured in all 3 cycles will be used to track trends of levels in Canadians over time and to assess the effectiveness of regulatory and health risk management actions. For new chemicals included in cycle 3, these national data will be used as an important baseline, or starting point, for future monitoring and research. Data for chemicals that were measured only in cycle 1 and/or cycle 2 can be found in the first and second Reports.
The 48 chemicals measured in the third cycle of the CHMS were selected based on one or more of the following considerations:
The third cycle of the CHMS contains approximately 69% of the same chemicals measured in cycles 1 and/or 2, and approximately 31% new chemicals. The CHMS is an ongoing study conducted in two-year cycles. As such, chemicals can be rotated in and out of the biomonitoring component. In some cases, chemicals have been repeated in cycle 3 to obtain additional information or a larger number of samples. In other cases, chemicals have been removed and may be added back in later cycles. New chemicals have been included to obtain national baseline data where none may have existed before.
|Cycle 1||Cycle 2||Cycle 3|
|Polybrominated flame retardants||Yes||No||No|
|Metals and trace elements||Yes||Yes||Yes|
|Polycyclic aromatic hydrocarbons||No||Yes||Yes|
|Volatile organic compounds: Benzene metabolites||No||Yes||Yes|
|Volatile organic compounds||No||No||Yes|
Table 1 lists the groups of chemicals measured in cycle 3 of the CHMS. Detailed chemical summaries are available in the full Third Report.
|Chemical groups||Chemicals measured|
|Metals and trace elements||6 arsenic species, cadmium, fluoride, lead, 3 forms of mercury|
|Environmental phenols||bisphenol A, triclosan|
|Polycyclic aromatic hydrocarbons||4 chrysene metabolites, 1 fluoranthene metabolite, 3 fluorene metabolites, 5 phenanthrene metabolites, 1 pyrene metabolite, 1 benzo[a]pyrene metabolite, 2 naphthalene metabolites|
|Volatile organic compounds||benzene (and 2 benzene metabolites), ethylbenzene, styrene, tetrachloroethylene, toluene, trichloroethylene, xylenes, bromodichloromethane, dibromochloromethane, tribromomethane, trichloromethane|
The biomonitoring data obtained in the CHMS survey will enable scientists, health professionals, and policy makers to do the following:
Biomonitoring is a valuable tool to measure exposure to chemicals; however, its limitations, as well as the reasons for these limitations, must be understood in order to use the data appropriately.
Biomonitoring provides an estimate of exposure to a chemical. However, a chemical's presence alone will not necessarily result in adverse health effects. The risk a chemical substance poses is determined by evaluating both its toxicity and the levels to which people may be exposed. The Government of Canada conducts risk assessments for chemicals used, manufactured, and imported into Canada, including the majority of chemicals measured in the CHMS. It has developed guidance values for mercury and lead in blood, to indicate what levels of exposure may be of concern. If measured levels are above the guidance values, actions may be considered to reduce exposure. The Government of Canada may consider developing guidance values for additional chemicals measured in the CHMS where there is enough information.
The Government of Canada plays a key role in protecting Canadians from exposure to chemicals through legislation that governs chemicals in food, soil, water, drugs, pesticides, and consumer products. This legislation includes the Canadian Environmental Protection Act, 1999, the Pest Control Products Act, the Food and Drugs Act, and the Canada Consumer Product Safety Act.
The Government of Canada takes a risk-based approach to the management of chemicals, using strong science, assessment, and monitoring, combined with a variety of tools to protect human health. Many standards and guidelines are in place (for example, Guidelines for Canadian Drinking Water Quality) to protect Canadians and the environment from the risks of potentially harmful chemicals.
Risk management strategies (such as the removal of lead from gasoline and other products) are designed to reduce exposure to chemicals. The effectiveness of these strategies may be observed by comparing biomonitoring data from future cycles of the CHMS with the current results.
In 2006, the Government of Canada launched the Chemicals Management Plan (CMP) to further enhance its role in protecting Canadians and their environment from exposure to chemicals. In addition to risk assessment and risk management activities, research and monitoring initiatives, including biomonitoring, are key components that inform decisions made under this plan. Monitoring initiatives include a comprehensive national biomonitoring component, of which the CHMS is the cornerstone.
The CMP supports a number of additional research, monitoring and assessment activities to help Canadians better understand their exposure and the potential effects on human health. These activities include biomonitoring studies targeting vulnerable populations (such as the Maternal-Infant Research on Environmental Chemicals study), environmental monitoring studies, and research to support biomonitoring. Health Canada also partners with Aboriginal Affairs and Northern Development Canada's Northern Contaminants Program to undertake health research and biomonitoring in Canada's northern populations. Detailed information about CMP-supported monitoring studies can be found on the Government of Canada's Chemical Substances website.
The biomonitoring component of the CHMS is an important step to increase scientific knowledge about Canadians' exposure to chemicals. The Government of Canada can expect researchers from Canada and around the world to use the biomonitoring data in the Third Report on Human Biomonitoring of Environmental Chemicals in Canada. Health Canada scientists will study associations, if any, between biomonitoring measurements and other health and lifestyle factors measured in the CHMS. Where possible, the data will be compared with population data from other countries that have performed national biomonitoring studies. Compiling data from past and future cycles of the CHMS will allow Health Canada to track changes in levels of chemicals in the Canadian population over time. All of this information will assist the Government in its assessment and management of chemicals in Canada.
Additional information about how the Government of Canada manages chemicals can be found on the Chemicals Substances website.
Additional information about the CHMS can be found on the Statistics Canada website.
For additional information on some of the chemicals included in the CHMS and advice on how to reduce exposure, visit the following links:
|Chemical||For More Information|
|Polycyclic Aromatic Hydrocarbons|
|Pyrethroid and 2,4-D pesticides|
|Nicotine exposure - Cotinine|
|Volatile Organic Compounds|