Biomarkers of Exposure

Every day, Canadians are exposed to a wide range of chemicals in the environment, food and other consumer products. While most chemicals are safe and don't pose a hazard to health, some may be toxic and cause adverse health effects. This is why it's important to determine the extent to which Canadians are exposed to different chemicals.

What is a biomarker of exposure?

When a person is exposed to a chemical--by direct contact, inhaling it or ingesting it--a substance corresponding to the chemical may be found in the body. This substance is generally called a "biomarker of exposure."

Biomarkers of exposure are often the products of metabolism and can be measured in the urine, blood, saliva and/or hair. The level of a specific biomarker in the body measures the extent to which a person may be exposed to a chemical.

An ideal biomarker of exposure should meet the following three criteria:

1. A biomarker of exposure should be specific to the chemical being studied.
2. The biomarker should remain long enough in the body to make sure its measurement is reliable.
3. The biomarker should be simple to collect and measure--for example, be present in urine, blood, or saliva.^{Footnote 1} ,^{Footnote 4} 

Tobacco-specific biomarkers of exposure

The use of tobacco products and exposure to tobacco smoke may cause serious illnesses, such as heart disease, respiratory diseases and cancer.^{Footnote 3}   Tobacco smoke is considered to be an environmental toxicant. It contains more than 4,000 chemicals and more than 70 of these chemicals are known to cause, initiate, and promote cancer (Footnote 2    Smokeless tobacco products also contain many of the same toxic chemicals.

How much exposure there is to tobacco products and tobacco smoke may be determined by measuring biomarkers of exposure specific to tobacco, such as NNALs, as well as nicotine and its metabolites. Measuring the exposure of the Canadian population to tobacco products and tobacco smoke is important so the information can be used to support the development of tobacco control strategies.

Glossary of Terms

Metabolism

The whole range of biochemical processes that occur within an organism. Metabolism consists of build-up and breakdown of substances.

Metabolite

The substance, or product, resulting from a metabolic process.

Specific

Related in application, or effect, to a particular chemical, structure, or process.

Toxicant

Artificially produced poison or poisonous substance.

Uptake

Absorption and incorporation of a substance by live tissue.

Footnotes