Source: Health Canada
Dioxins and furans are the common names of toxic chemicals found in very small amounts in the environment, including air, water and soil. Because they are present in the environment, they are also found in some foods.
Exposure to dioxins and furans has been associated with a wide range of adverse health effects in humans and laboratory animals. The type and frequency of adverse reactions generally depend on the duration and level of exposure.
There are 210 different dioxins and furans. All have the same dioxins "structure" chemical base and have all of the chlorine atoms. This is the same for furans, except that their chemical structure is different. The toxicity of these substances varies greatly. This is the most toxic is called 2,3,7,8-TCDD or simply TCDD.
The large-scale incineration of municipal and medical waste is the largest source of dioxins and furans in Canada. Other important sources include:
Dioxins can also result from natural causes such as forest fires and volcanic eruptions. Most dioxins are introduced into the environment through the air. The chemicals in the air can attach to small particles and thus travel considerable distances in the atmosphere, which means that Canadians may be exposed to dioxins and furans produced in other countries.
Dioxins and furans are found in the food chain because they remain stored in fatty tissues of animals. This is the reason why people consume a greater amount of dioxins and furans from the food by air, water or soil. Eighty-five percent of dioxin exposure is through food. Meat, dairy products and fish contain higher concentrations of dioxins and furans as fruits, vegetables and grains.
Scientists have studied the effects of dioxins and furans in laboratory animals. They also studied the effects on the health of people who were exposed to dioxin as a result of an occupational accident or exposure to certain herbicides before the adoption of improved manufacturing processes to reduce these contaminants.
Studies show that dioxins and furans can have many effects on the health of animals and humans. Among the health effects associated with human exposure to dioxins include:
It is important to remember that with any chemicals, including dioxins, health risk depends on many factors, including:
It is a complex problem that scientists do not have all the answers, but they agree that the degree of exposure to dioxins and furans should be as low as possible.