Bisphenol A exposure

Two-year-old Travis Bean plays with a protest sign during rally at Queen's Park November 20, 2007. A new Canadian study found concentrations of BPA in urine were higher for children aged 6 to 11 than they were for adults aged 40 to 79.

OTTAWA—It's found in some plastic bottles and in the linings of tin cans — and probably in your urine, too.

Most Canadians have low levels of a chemical called bisphenol A in their urine, a new federal study has found.

The Canadian Health Measures Survey, released Monday by Statistics Canada, found the chemical in 91 per cent of Canadians aged six to 79.

The study, conducted between 2007 and 2009, analyzed blood and urine samples for indicators of more than 80 environmental contaminants and chemical substances.

Researchers also found the amount of lead in people's blood has fallen dramatically since they were last measured 30 years ago, while most blood tests turned up detectable levels of mercury.

But the findings didn't alarm Health Canada's senior medical adviser.

“We live in an environment where we use chemicals very, very widely,” Dr. Paul Gully said.

“Therefore exposure and finding them is not a surprise. We take all the chemicals seriously, which is why action is being taken already.

“But in terms of any particular result, bisphenol A being one of them, we will look at them carefully. But there are no results which demand immediate action.”

This is the first time the government has measured bisphenol A concentrations across the country. The chemical is used to harden plastic in water bottles, canned food lining and hundreds of other household items.

The federal government has already banned the sale of polycarbonate plastic baby bottles that contain bisphenol A.

Many retailers pulled plastic water and baby bottles from their shelves before the government announced the ban in 2008, as consumers began demanding products without bisphenol A in them.

The Chemical Industry Association of Canada urged caution in interpreting this latest study.

“Thanks to advances in analytical chemistry, researchers are able to measure extraordinarily low levels of natural and man-made substances in human fluids and tissues — often as little as one part per billion (a single drop in an Olympic-sized swimming pool),” the group said in a statement.

“Of course, health researchers know that the simple presence of an environmental chemical in a person's body does not mean that it will cause health effects or disease.”

Some scientists believe exposure to bisphenol A can harm the reproductive and nervous systems and possibly promote cancers. They point to dozens of animal studies, though the negative effects have not been recorded in human studies.

The survey says those measured had a mean concentration of 1.16 micrograms per litre in their urine. That's consistent with results from international studies, which have been reporting mean or median concentrations of one to three micrograms per litre.

The Canadian study found concentrations of BPA in urine were higher for children aged 6 to 11 than for adults aged 40 to 79. The study found the highest concentrations in teens.

“Given the short half-life of orally ingested BPA and the high frequency of detection, the ... data suggest continual widespread exposure in the Canadian population,” it said.

One of the country's leading toxicology experts said he isn't overly worried by the findings.

“I don't think we should alarm the public that there's a huge problem there. I don't think there is,” said Dr. John Giesy, a professor at the University of Saskatchewan and the Canada Research Chair in Environmental Toxicology.

“But, at the same time, all chemicals can be toxic. We know lead and mercury do cause effects at small levels, and we should always be prudent and we should always be vigilant.”

Health Canada will look at the results of the study before deciding if further action is necessary, Gully said.

But Rick Smith of the lobby group Environmental Defence predicted it's only a matter of time before bisphenol A is banned in all products sold in Canada.

“The writing's on the wall for this chemical,” he said.

Smith added that he was encouraged the study found the amount of lead in people's blood has dropped.

Although everyone tested positive for lead, fewer than one per cent had concentrations at or above the intervention level of 10 micrograms per decilitre of blood.

Older adults and males had significantly higher lead concentrations.

“Lower household income, being born outside Canada, living in a dwelling at least 50 years old, current or former smoking, and drinking alcohol at least once a week were associated with higher (lead levels),” said the study.

“Although ... concentrations have declined dramatically since the 1970s, socio-demographic characteristics, the age of dwellings, and certain lifestyle behaviours are associated with higher levels.”

The study also found 88 per cent had detectable concentrations of mercury in their blood.

Mercury concentrations were lower for children and teens aged six to 19 than for adults aged 20 to 79.