Residents of the village of Fort Chipewyan, a one-time trading post on the northeast shore of Lake Athabasca, say oil sands developments may be responsible for rare bile-duct cancers first spotted by a doctor in the community in 2006.
Those complaints sparked a study by Alberta health authorities, which released the results Friday.
The study said that while the incidence of the rare cancer cholangiocarcinoma was higher than expected, only two of the six cases reported by the community's doctor were confirmed, while three were other types of cancer, and one was not cancer at all.
However, the study found 47 individuals in the community had 51 different cancers over the 1995 to 2006 study period, more that the 39 cases health officials had expected to find.
"The overall findings show no cause for alarm," said Dr. Tony Fields, a vice-president at Alberta Health Services. "But they do, however, point to the need for some more investigation."
The village is about 260 kilometres (160 miles) north of Fort McMurray, where a number of projects have been established to mine the oil sands, as part of the process that converts the tar-like bitumen stripped from the sand into synthetic crude oil.
Lake Athabasca is fed by the Athabasca River, which flows through the project region, and earlier studies have found unsafe levels of arsenic, mercury and polycyclic aromatic hydrocarbon in the lake's fish, as well as in sediments, water and wildlife.
While oil sands producers use large amounts of water to produce the crude, contaminated wastes are kept on-site and are not released into the river.
Fields said the higher than expected number of cancer cases in Fort Chipewyan could be due to chance, increased detection, or lifestyle and environmental risks. He said more monitoring of the community is needed to see if the higher number of cancers is a trend.
The results of the study did not assuage community officials, who say they have not been provided with a copy of the results.
"We haven't seen it," said Steve Courtoreille, a councilor with the Mikisew Cree First Nation and chairman of the Nunee Health Board Society. "We've asked for it so our doctors can critique but they caught us off guard. It's not going to show the real picture ... There is a problem here."
Alberta Health Services said the study's findings were reviewed by independent experts and two Canadian aboriginal researchers.
