Human Biomonitoring of Environmental Chemical Substances
Human biomonitoring is an important tool to measure our exposure to chemical substances in the environment. What we learn from human biomonitoring helps us understand and manage the health risk chemical substances can pose.
What is human biomonitoring?
Biomonitoring is the measurement of a chemical substance, the products it makes after it has broken down, and how it might interact in the body. Measurements are usually taken in blood and urine, and sometimes use hair, saliva or breast milk.
How is human biomonitoring done?
A human biomonitoring study involves several steps. First, the study is designed. This means we set out goals, determine who in the population will be studied and which chemical substances will be measured. Then the study is conducted using volunteers who agree to participate. Information is collected through questionnaires, tissue or fluid samples and laboratory analysis. The results are analyzed and interpreted.
Which populations are studied?
Biomonitoring studies may involve the general population or sub-populations (these might be women of child-bearing age, children or specific ethnic populations). The way the study is designed has a lot to do with whether it can be applied to a larger group of people.
What do human biomonitoring studies tell us?
Large national or regional-scale biomonitoring surveys can help monitor Canadians' exposure to chemical substances and help us determine if the exposure is changing over time and whether our actions are effective. Biomonitoring studies that focus on sub-populations can help us compare levels of exposure for that particular group in comparison to the broader population. Biomonitoring is also used in studies, known as epidemiological studies, examining the cause and effect between health problems and exposure to environmental chemicals.
The Canadian Health Measures Survey and biomonitoring
The Canadian Health Measures Survey is a national survey that will be carried out by Statistics Canada and collect information from Canadians about their health. The study, which will be carried out from 2007 to 2009, will include a biomonitoring component to measure human levels of environmental chemicals in a sample that represents the overall Canadian population. Five thousand Canadians between the ages of 6 and 79 will be tested in the survey. Blood and urine samples will be collected from some of the participants and analyzed for a number of substances, including:
- metals,
- phthalates,
- polychlorinated biphenyls (PCBs),
- brominated flame retardants,
- organochlorine pesticides,
- organophosphate insecticide metabolites,
- phenoxy herbicides,
- continine,
- perfluorinated compounds, and
- bisphenol-A.
There will also be a questionnaire about risk factors related to exposure to these substances. This first-ever national survey will establish a representative baseline of the concentrations of environmental chemical substances that end up finding their way into the bodies of Canadians. It will help determine future trends and allow comparisons to other countries. The presence of a given substance in blood or other samples is not necessarily an indication of harmful effects. Better measurement and monitoring, on the other hand, will give scientists valuable data in making those determinations and proposing prevention or remedial measures where needed.
More information about the Chemicals Management Plan, including the list of substances to be addressed, can be found via the Chemical Substances Portal at http://www.chemicalsubstances.gc.ca.
Resources Available
For additional information on biomonitoring, consult the following links below.
 Human Biomonitoring of Environmental Chemicals
(source: Health Canada)
Biomonitoring and Canadian Health Measures Survey
(source: Health Canada)
|
