BPA: a common threat?

New numbers released on Monday by Statistics Canada show that more than 90 per cent of Canadians aged six to 79 years old had detectable concentrations of Bisphenol A (BPA) in their urine.

But what is the substance, and why is it a cause for concern? Global News takes a look at the common chemical compound BPA and its potential risks.

What is it?

BPA forms the basis of a clear plastic known as polycarbonate. It is a man-made chemical that has been used for decades to harden plastics.

How is it used?

The substance is used to make products like reusable water bottles, baby bottles, lenses, helmets, goggles, toys, CDs, DVDs, and as a coating for most dental fillings.

BPA is also found in epoxy resins, which act as a protective lining on the inside of metal-based food and beverage cans.

What’s the risk?

Some studies on animals have suggested that low levels of exposure to BPA early in life can affect neural development and behaviour.

The compound often imitates estrogen in animals once it is consumed, raising concerns that, if it exhibits the same characteristic in humans, it could increase the risk of breast cancer and earlier onset of puberty in females.

Canada was the first country in the world to crack down on BPA, and has declared the substance toxic.

How much are we exposed to?

The findings show that Canadians are consistently exposed to the chemical, even though it is quickly excreted from the body.

International studies show that one to three micrograms of BPA per litre of urine is the typical level seen in adults. Canadians are on the lower end of that scale, averaging about 1.6 micrograms.

Still, it is unclear how these small amounts of BPA affect human health.

As a safety precaution, the Canadian government banned the use of BPA in baby bottles in 2008 after studies showed most babies were exposed to BPA leaching through the lining of cans into liquid infant formula.

But the substance is still used as a liner inside almost all food and beverage containers in Canada. Dental sealants and white fillings also contain small amounts of BPA.

Pediatric dentists say the amount of BPA used in children’s mouths is too small to cause a problem, but the Canadian Dental Association is advising members to start searching for BPA-free dental materials.