StatsCan to test 5,000 people for toxins

The federal government's first large-scale survey mirrors similar efforts in the United States that have found that virtually the entire population carries a complex burden of pollutants in their tissues.

The blood and urine will be subjected to a battery of expensive tests that will check for 70 metals and chemicals, including DDT, the once widely used insecticide that has been banned for decades.

DDT is still found throughout the environment because it degrades so slowly.

Many of the substances to be monitored have only recently emerged as potential health threats, and are a worry because the chemicals appear to be leaking out of common consumer products and getting into people.

Bisphenol A, for instance, is a compound that mimics the female sex hormone estrogen and is the main component of polycarbonate, used to make hard-plastic water bottles and dental sealants.

Phthalates are a ubiquitous plastic softener found in many cosmetics and which contribute to the distinctive smell of new cars.

Phthalates concern researchers because they appear able to interfere with the normal functioning of male hormones.

The tests will also look at brominated flame retardants, a widely used family of chemicals that reduce the fire hazard of mattresses and computers, but have been linked in animal experiments to problems resembling attention-deficit disorders in children.

It is unknown whether current exposures to these substances or their interactions in people's bodies is harmful, although animal experimentation has found that during early life and fetal development even trace exposures to some of the substances can skew development in ways that increase the chances of cancers and other health problems later in life.

The U.S. has been issuing results of large-scale testing for contaminants, a process known as biomonitoring, since 2001.

The testing has discovered that the public carries a bewildering cocktail of chemicals from day-to-day exposures to substances originating in consumer products, polluting industries and residues on food. However, the U.S. work has also shown that efforts to ban harmful substances, like the end of the sale of leaded gasoline, have been quickly reflected in reduced levels of the brain-damaging heavy metal in children.