Environmental contaminants are chemicals that accidentally or deliberately enter the environment, often, but not always, as a result of human activities. Some of these contaminants may have been manufactured for industrial use and because they are very stable, they do not break down easily. If released to the environment, these contaminants may enter the food chain. Other environmental contaminants are naturally-occurring chemicals, but industrial activity may increase their mobility or increase the amount available to circulate in the environment, allowing them to enter the food chain at higher levels than would otherwise occur.
A wide variety of environmental contaminants have been detected in foods. These range from metals and "ionic" species like perchlorate to organic (carbon-based) substances, including the so-called "persistent organic pollutants" or POPs (named for their ability to exist in the environment for prolonged periods without breaking down). Legacy POPs such as PCBs have been banned for industrial or agricultural use in Canada for many years, but remain in the food chain. Other POPs have been more recently identified, having been found in the environment and the food chain (for example, brominated flame retardants).
Health Canada assesses the risks posed to Canadians by environmental contaminants in food. In support of these risk assessment activities, scientists monitor the concentrations of various environmental contaminants in foods through the ongoing Total Diet Study. Health Canada scientists also research and evaluate the toxicity of environmental contaminants to humans, participate in international evaluations of the toxicity of contaminants, and monitor the results of new studies as they become available. When necessary, Health Canada sets maximum levels (standards) for contaminants in foods.
Environment Canada also works to reduce the human input of environmental contaminants into water, air and land.
Health Canada has provided advice on food preparation methods that reduce exposure to dioxins and furans, as well as to PCBs. Health Canada has also provided advice on how to enjoy the health benefits of fish consumption while reducing the risks of exposure to mercury. The advice may be viewed by clicking on the Dioxins and Furans, the PCBs, and the Mercury links listed above and in the Topics Box. Health Canada generally recommends that Canadians consume a variety of foods from each food group included in Eating Well with Canada's Food Guide and follow any provincial or territorial consumption advice for eating sport fish.