Cat. No.: H128-1/10-613E-PDF
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This overview is a companion piece to the 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 environmental chemicals and the potential effects this exposure may have on health. Human exposure to chemicals can be estimated indirectly by measuring chemicals in the environment, food, or products, or directly using biomonitoring (see Figure 1).
Health Canada's Report on Human Biomonitoring of Environmental Chemicals in Canada presents the first-ever comprehensive set of biomonitoring data on the Canadian population's exposure to environmental chemicals, collected as part of the Canadian Health Measures Survey. The Report provides information to scientists and decision makers on the levels of chemical substances in Canadians. These baseline measures are an important starting point for future monitoring and research related to chemical exposure.
Biomonitoring is the measurement, in people, of a chemical or the products a chemical makes when it breaks down. This measurement is usually taken in blood and urine and sometimes in other tissues and fl uids 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 measures health survey conducted in Canada. The survey, which is designed to represent the Canadian population, collects information on the general health and lifestyles of Canadians through interviews and direct physical measurements (for example, weight and height), to provide 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 environmental chemicals.
The first cycle of the CHMS involved approximately 5,600 Canadians between the ages of 6 and 79 years at 15 sites across the country. Data collection took place between March 2007 and February 2009.
Collection for the second cycle of the CHMS began in September 2009 and includes children as young as 3 years of age. The second cycle will be completed in 2011, while planning for future cycles is already underway.
The Report on Human Biomonitoring of Environmental Chemicals in Canada provides the results of the biomonitoring component from the first cycle of the CHMS. This first set of national data will be used as an important baseline, or starting point, for future monitoring and research. The primary purpose of the 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 Report describes the survey methods used and includes the following information for each chemical or chemical group:
The Report provides biomonitoring results, presented in tables, for 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 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 percent of the people measured are below this concentration and 5 percent of people are above it.
The 91 chemicals measured in the first cycle of the CHMS were selected based on one or more of the following considerations:
Table 1 lists the types of substances measured in the CHMS. Detailed chemical summaries are available in the full Report.
|Metals||antimony, arsenic, cadmium, copper, lead, manganese, mercury, molybdenum, nickel, selenium, uranium, vanadium, zinc|
|Organochlorines||14 substances, including aldrin, chlordane, DDT, hexachlorobenzene, hexachlorocyclohexane, mirex, toxaphene|
|Polychlorinated biphenyls (PCBs)||24 substances and Aroclor 1260|
|Polybrominated flame retardants (PBDEs)||10 substances|
|Perfluorinated compounds (PFCs)||PFOS, PFOA, PFHxS|
|Phthalates*||11 metabolites (breakdown products)|
|Environmental phenol||bisphenol A|
|Pesticides||6 organophosphate metabolites, 5 pyrethroid metabolites, 2,4-dichlorophenoxyacetic acid (2,4-D)|
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 environmental 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 is currently developing guidance values for biomonitoring of 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 harmful chemicals through legislation that governs chemical substances in food, 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 Hazardous Products Act.
The Government takes a risk-based approach to the management of chemical substances, 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 harmful 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 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 Indian and Northern Affairs 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: www.chemicalsubstanceschimiques.gc.ca/plan/surveil/index-eng.php
The biomonitoring component of the CHMS is a first and very important step to increase scientific knowledge about Canadians' exposure to environmental chemicals. The Government of Canada can expect researchers from Canada and around the world to extensively use the biomonitoring data in the 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 future cycles of the CHMS will allow Health Canada to track changes in exposure to chemicals in the Canadian population over time. All of this information will assist the Government in its assessment and management of environmental chemicals in Canada.
Additional information about how the Government of Canada manages chemicals can be found on the Chemicals Substances website at www.chemicalsubstances.gc.ca.
Additional information about the CHMS can be found on the Statistics Canada website at www.statcan.gc.ca/survey-enquete/household-menages/5071-eng.htm.
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|
|Polychlorinated biphenyls (PCBs)||
|Polybrominated flame retardants (PBDEs)||
|Perfluorinated compounds (PFCs)||
|Tobacco Exposure - Cotinine||