Environmentalists are outraged at a pipeline they say could leak toxic chemicals into a drinking water dam in WA. 

Mining giant Alcoa has been accused of negligence after building an unauthorised pipeline in the state’s south-west. 

WA’s Department of Water and Environmental Regulation has issued a prevention notice to Alcoa due to concerns over the pipeline, which was built as part of a PFAS treatment plant at its Willowdale bauxite mine. 

The authority said there is a “real and not remote” possibility that Per-and poly-fluoroalkyl substances, or PFAS, could leak into the Samson Dam that provides drinking water to the nearby town of Waroona. The department ordered the pipeline to be cleaned out within two days of the notice being issued.

Deputy Premier and Minister for State Development Roger Cook has expressed concern, saying the notice “reflects poorly on the performance of Alcoa”, and calling on the company to rectify the situation as a matter of urgency.

Alcoa claims it informed the department before the pipe was constructed and used, and that it needed to act swiftly due to the risk of overflow from winter stormwater. 

The company says it discovered small concentrations of PFAS at their Huntly and Willowdale bauxite mines in 2019 and immediately stopped using the foams containing those compounds. 

Alcoa maintains it only used the pipe for a two-week period last August, and no leaks had been detected.

Kingsley Dixon, a restoration ecologist and Director of the Australian Research Council Centre for Mine Site Restoration, said it is particularly concerning given Alcoa's recent scrutiny over contaminated runoff from a bauxite mine near the Serpentine Dam, which supplies almost 20 per cent of the city's drinking water. 

Professor Dixon said that as a Waroona resident, he was particularly alarmed and urged due diligence to ensure environmental care and consultation was done with the community.

The WA Forest Alliance has referred Alcoa's mine management plan to the Environmental Protection Agency for review. 

Professor Dixon also questioned whether Alcoa can be trusted with its other mine developments and is urging the government to look at penalties. 

Companies can face fines of up to $100,000 for violation of section 53(1) of the Environmental Protection Act, which relates to the discharge of waste.