Human Biomonitoring of Environmental Chemicals

Canadians are exposed to a variety of chemicals, both naturally-occurring and man-made, throughout their daily lives. We understand that many of these substances are in our bodies, and there are questions about the potential for these chemicals to affect our health. Public health officials and government regulators need better and more direct measurements of exposure to these chemicals in order to improve decisions for protecting health and preventing disease.

Biomonitoring is a key tool used as an indicator and quantitative measure of exposure to chemicals in the environment. Human biomonitoring data contribute to our understanding of exposure and provide information to inform the management of the health risks posed by chemicals.

What is Biomonitoring?

Biomonitoring is the measurement of a chemical, the products it makes after it has broken down, or the products that might result from interactions in the body. These measurements are usually taken in blood and urine and sometimes in other tissues such as hair, saliva and breast milk.

It is difficult to predict levels of chemical substances in people using estimates or measurements of chemicals in air, soil, water, food or commercial products. This is because we have to make assumptions about personal habits and lifestyles, and make assumptions about how the chemical substances are absorbed, distributed, used and eliminated from the body. Biomonitoring provides a more direct estimate of chemical exposure and will help to make sound decisions about the health of Canadians.

What Human Biomonitoring Studies Tell Us

Large national or regional-scale biomonitoring surveys can help measure our exposure to chemical substances, and help us determine if the exposure is changing over time. An example of such a study is the Canadian Health Measures Survey, a national survey being led by Statistics Canada, in partnership with Health Canada and the Public Health Agency of Canada. This survey collects information from Canadians about their general health, but also includes measurements of environmental chemicals in blood and urine samples.

National studies such as the CHMS will provide us with baseline levels of chemicals in Canadians and will also provide the basis for future monitoring and research activities.

Using Human Biomonitoring Data

Human biomonitoring data can be used by government, researchers and health practitioners in a wide variety of ways:

1. To establish baseline levels of chemicals in the Canadian population.
2. To compare exposure to environmental chemicals among different populations.
3. To help identify priority chemicals for which further action should be taken to protect the public's health.
4. To assess the effectiveness of regulatory and environmental risk management actions intended to reduce exposure to specific chemicals and the associated health risks.
5. To support future research on potential links between exposure to certain chemicals and specific health effects.
6. To contribute to international monitoring programs.

Limitations

Human biomonitoring is an important tool; however, there are certain limitations in its use. Although technological advances in laboratory methods have improved our ability to measure chemicals and generate biomonitoring data, our ability to interpret biomonitoring results in relation to the risks the levels pose to health is limited. More work needs to be done to assess the sources of exposure and to evaluate the toxicological and health impacts of exposure to environmental chemicals. For many chemicals, further research is needed to understand what health effects may be related to different levels of these.

The Government of Canada's Role

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.

In addition to biomonitoring surveys and studies, Health Canada performs science and research that support biomonitoring. This includes the development of new chemical measurements and analytical methodologies, the development of tools to better interpret biomonitoring results, and the investigation of possible adverse health effects that may result from exposure to environmental chemicals. This will lead to more effective use of biomonitoring data in managing the health risks of chemicals and enhance our ability to interpret and communicate biomonitoring study results. In addition, Health Canada has a leadership role in producing and disseminating national biomonitoring data, identifying new priority substances for future studies, contributing to international monitoring efforts, and facilitating cooperation with other organizations with an interest in biomonitoring.