Suncor is reporting the release of six million litres of water from a pond on its Fort Hills oilsands mine north of Fort McMurray, Alta., that exceeded guidelines for sediment.

In a note to area First Nations, the Alberta Energy Regulator says the water is from a pond used to settle suspended solids in surface water collected from parts of the site that haven’t been mined.

Once the sediments settle, the water is emptied into a creek that drains into the Athabasca River.

The regulator, which was told of the problem Sunday, says the level of solids in the water is more than twice the allowed limit.

Suncor says it has stopped outflow from the pond and is studying the cause of the problem and how it affected water quality.

Spokespeople for the Athabasca Chipewyan First Nation and Mikisew Cree First Nation say the bands were notified of the release Monday.