Alberta Environment is investigating after water containing a higher-than-permitted amount of grease and oil was discharged into the Athabasca River from a Suncor oilsands development north of Fort McMurray early Tuesday.

The water wasn't from a tailings pond, which contains waste from bitumen processing. Instead, it came from a cooling water pond that contains treated water from machinery such as industrial heaters, Suncor said.

Treated water is released into the river as a normal procedure at the development.

However, according to Alberta Environment and Suncor, there were higher amounts of hydrocarbon in a recent discharge of about 348,000 litres of water.

Under Alberta Environment legislation, the water should contain a very small amount of hydrocarbon — no more than five parts per million, or about five drops for every 50 litres.

Some samples of the recently discharged water contained less — 0.02 parts per million — but other samples showed as much as 42 parts per million.

"It doesn't seem like it's a very serious release," said Alberta Environment spokesman Jason Cobb. "However, we do take it seriously and that's why we're following the procedures that are outlined and that we expect to be able to determine what the impacts may or may not be.

Investigators are also testing water in the Athabasca River that is downstream from the discharge point.

Community leaders frustrated

Fort Chipewyan is downstream from the Suncor developments, and the company sent the community a notice telling residents about the discharge.

But community leaders are frustrated that didn't occur until about 12 hours after it happened.

People in Fort Chipewyan have long been concerned about local rates of cancer they believe are higher than average because of oilsands development, and this latest incident has community members frustrated, said George Poitras, who is from the Mikisew Cree First Nation.

"Anything that is being discharged into the Athabasca River is of grave concern to the community of Fort Chipewyan," Poitras said.

Alberta Environment is also investigating a second discharge that happened in the Athabasca River within the past year.

Environment Canada told CBC News on Wednesday that it is also on the site of the latest discharge investigating whether there's been a violation of the Fisheries Act.