Teens Carry 30 Percent More BPA Than Adults

BPA is an industrial chemical used to make hard, clear plastics for water bottles and baby bottles, and resins to line food and beverage cans. It is also found in the special paper used to print receipts. An endocrine disruptor, it mimics the effect of estrogen in the human body and interferes with the function of other hormones.

"Phthalates and [BPA] … aren't quite identical to the natural hormone molecules in men's or women's bodies, but they come close enough that they occupy the same receptors on estrogen-sensitive tissues and exert their own unique effects on human health," writes David Steinman in his book Safe Trip to Eden.

BPA has been linked with an increased risk of cancer, reproductive and nervous problems, including changes in the brain.

Researchers collected urine samples from more than 5,400 Canadians between the ages of six and 79, testing for traces of BPA. They found traces of the toxin in 91 percent of those tested.

Teenagers might have higher levels because they consume more food relative to their body weight, the researchers suggested, or because they metabolize it differently. Researchers expressed concern that these higher levels might pose an even more severe risk of developmental problems at an age when the body is undergoing major changes.

The average level of BPA found was just over one part per billion, 1,000 times the level at which estrogen is naturally found in the body.

Health Canada has officially designated BPA as a toxic chemical and ordered its removal from baby bottles, but most other countries have yet to follow suit.

"The No. 1 priority at the moment has got to be getting it out of the lining of tin cans," said Rick Smith of Environmental Defense. "When nine out of 10 Canadians have a hormonally active chemical in their body, for which easy alternatives are available … why not make some further changes with respect to BPA?"