TORONTO

The level of lead contamination in the bloodstreams of Canadians has plummeted over the past 30 years, a likely result of the phasing out of lead in gasoline, paints and the solder used to seal food cans, Statistics Canada reports.

Where 25 per cent of Canadians had blood lead concentrations above the unsafe threshold in 1978, a survey conducted in 2007-2008 showed that figure had dropped to under one per cent.

Blood contamination levels were also low for two other dangerous metals, mercury and cadmium, the report showed.

The head of the occupational environmental health laboratory at McMaster University in Hamilton, called the numbers "amazing.''

"To go from 25 per cent down to about one is a pretty dramatic drop,'' said Brian McCarry, who holds a research chair in environment and health at the university.

"This is a good news story for sure.''

A colleague from McMaster agreed, saying the reduction shows the measures taken to reduce Canadians' exposure to lead have paid off.

"Phasing lead out of gasoline is probably one of the best stories I know of regulation impacting on exposures in human health,'' said Warren Foster, an expert in reproductive endocrinology and toxicology who teaches in the school of medicine.

"Because we phased it out of gasoline and lead-based paints, we've seen the levels drop in the population.''

Neither McCarry nor Foster was involved in collecting or analyzing the Statistics Canada data.

The report is based on blood samples taken from 2,678 people from eight cities who took part in the Canadian Health Measures Survey, which the statistical agency is undertaking with Health Canada and the Public Health Agency of Canada.

The cities were Clarington, Kitchener, Waterloo and Toronto in Ontario, Monteregie and Montreal in Quebec, Moncton, N.B., Red Deer, Alta., and Vancouver.

These findings are considered preliminary. Additional samples will be taken until March 2009, at which point it is expected that the survey partners will have samples from 5,000 Canadians aged six to 79 from 15 sites across the country.

The preliminary report shows that the mean lead concentration was 1.37 micrograms per decilitre of blood in 2007-2008, well below the current Health Canada blood lead "guidance level,'' or threshold, of 10 micrograms per decilitre.