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Environmental expert to testify about impacts of toxic tailings waste on groundwater

Parliamentary Environment Committee to meet Feb. 6 to hear testimony

February 5, 2024  By Ground Water Canada

Ottawa – An environmental defence expert is to testify Feb. 6 before the Parliamentary Environment Committee (ENVI) about the impacts of tar sands mining, including its toxic tailings waste on groundwater.

The testimony from Aliénor Rougeot, climate and energy program manager, comes on the first anniversary of Imperial Oil’s Kearl mine disaster in the tar sands, which spilled 5.3 million litres of toxic tailings into the surrounding environment.

Rougeot will speak to the risks and impacts of the more than 1.4 trillion litres of tailings (wastewater produced in the oil extraction process) on groundwater. The tailings contain a dangerous mixture of chemicals, including heavy metals and naphthenic acids.


A recent scientific study has also revealed that tar sands companies have under-reported their toxic emissions by up to 6,300 per cent — a significant portion of which may be coming from toxic tailings. The full extent of the danger presented by oil sands process water on human health remains understudied.

Toxic tailings ponds now cover an area of more than 300 square kilometres, which is equivalent to 2.6 times the size of the City of Vancouver.

In 2020, the Commission for Environmental Cooperation surveyed all publicly available peer-reviewed studies and concluded there is scientifically valid evidence of oil sands process water (tailings) seepage into the groundwater around tailings ponds.

In February 2023, 5.3 million litres of wastewater spilled from the same Imperial Oil tailings area. The toxic waste leaked into boreal wetlands and tributaries where water drains to drinking water sources. It was only through this second spill that Indigenous communities fully learned of the extent of the pervasive below-ground leak, which is still ongoing to this day.

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