WASHINGTON — A new study has detected air pollutants, including carcinogens, in areas downwind of Canada's main fossil fuel hub in Alberta at levels rivaling those of major metropolises such as Beijing and Mexico City.
The study by researchers from UC Irvine and the University of Michigan also found a high incidence of blood cancers such as leukemia and non-Hodgkin's lymphoma among men in the area, compared with the rest of Alberta and Canada.
"When you get cancers that can be caused by the carcinogens we are seeing, that is reason for concern," said Isobel J. Simpson, a lead author of the study and a researcher at UC Irvine's chemistry department.
The Alberta government said the study provides an inaccurate picture of pollution in the so-called Industrial Heartland, a three-county area where oil, chemicals and oil sands crude are processed.
"Based on the results of our monitoring, we see no evidence to suggest that people in the Industrial Heartland region are exposed to levels of the chemicals indicated in the paper," said Nikki Booth, spokeswoman for Alberta Environment and Sustainable Resource Development, the provincial regulator.
The issue has drawn attention because most of the oil produced in Canada is shipped to the United States.
Three previous studies since 2009 have detected carcinogens in Alberta's rivers and lakes, near where oil sands are mined. The latest study focuses on a site where oil sands are processed, along with other fossil fuels.
The Industrial Heartland, northeast of the provincial capital, Edmonton, is surrounded largely by farmland. The Shell Scotford complex includes a refinery and a facility that processes 225,000 barrels a day of bitumen, a tarry substance that is extracted from northeastern Alberta's oil sands, diluted with chemicals and piped to the United States.
The study released this week is based on air samples taken over two days in 2010 around 10 facilities. Researchers measured volatile organic compounds, or VOCs, organic chemical mixtures created by certain industrial processes and consumption of fossil fuels, among other things.
VOCs contribute to climate change and formation of smog. They also contain cancer-causing substances such as benzene and 1,3-butadiene.
Tests showed that airborne concentrations of 1,3-butadiene were 322 times greater downwind of the industrial area than upwind. Similarly, downwind concentrations of benzene were 51 times greater.
The researchers said the compounds were consistent with emissions from the nearby facilities.
Simpson said funding allowed for only two days of sampling and the population that showed higher cancer rates was small. The researchers recommended better monitoring of air pollution and health, and suggested that facilities reduce emissions of known carcinogens.
"We don't want this to be study after study after study with no action," Simpson said. "There's enough here to recommend reducing carcinogens in this area."