Alcoa piped toxic waste over drinking water dam, and asked for approval afterwards

Bauxite miner Alcoa pumped PFAS-contaminated water over a dam in south-west WA without approval from the environment regulator or the knowledge of Water Corporation, which had judged the plan an “unacceptable risk to drinking water quality”.

In August 2022, Alcoa submitted a plan to the Department of Water and Environmental Regulation for a system to clean up water contaminated with toxic PFAS from past use of firefighting foam, but the document failed to mention that a white polyethylene pipeline over the dam was already installed.

The PFAS pipeline crosses Water Corporation’s Samson Dam. Credit: Anon.

That same month, when the public had an opportunity to comment on what they thought was a proposal for future work, the US aluminium giant flowed contaminated water through the pipeline over the Samson Dam east of Waroona for two weeks.

When this masthead last week revealed state government agencies had labelled the plan “an alarming prospect”, Alcoa issued a lengthy media statement but did not say it had already implemented much of the construction and used the pipeline.

PFAS are known as “forever chemicals” as they persist in the environment for such a long time. They have been shown to be toxic to some animals.

The environment regulator, Water Corporation and members of the public are worried a leak from the pipeline could contaminate the dam and would still be unaware of what Alcoa has done without the actions of a whistle-blower whose photos, published today by this masthead, show the 10-kilometre-long pipeline crossing the dam.

Satellite photos confirmed the pipeline was in place and that the construction of ponds to hold the water started in February 2021.

Water Corporation did not know Alcoa had constructed the pipeline over its dam, a spokesman said.

“It is Water Corporation’s view that such a pipeline would, along with other concerns, present an unacceptable risk to drinking water quality, therefore, Water Corporation does not support Alcoa’s proposal in its current form,” he said.

DWER has not granted Alcoa approval for the work, a department spokesman confirmed.

“The DWER compliance and enforcement team is actively investigating a complaint relating to the operations of Alcoa at its Willowdale mine site,” he said.

“Any further comment on the investigation would be inappropriate at this time.”

Alcoa’s plan to deal with PFAS-contaminated water at its Willowdale mine include the pipeline taking water over the dam to the Arundel mine, ponds to hold the water, a treatment plant at Arundel, and then another pipeline to move the treated water to McKnoes Brook for disposal.

An Alcoa spokeswoman said transporting the contaminated water from Orion to Arundel by a pipeline was safer than using trucks.

Water Corporation and DWER do not support moving the water long distances and want the PFAS dealt with at the contaminated sites, according to recent internal state government documentation.

Alcoa has spent $4 million so far – not including the treatment plant – managing what it believes is a low risk to the water catchment, the Alcoa spokeswoman said.

She said Alcoa used the pipeline just once, for two weeks in August 2022, to remove contaminated water from the water catchment when it was concerned about heavy winter downpours.

“We informed DWER that we would commence priority works on the construction of the water storage facilities and pipeline to mitigate potential risks during winter,” she said.

The unsecured PFAS pipeline meanders onto a road next to a bauxite conveyor.Credit: Anon.

“We also advised of our intention to seek a works approval for construction of a treatment plant.”

Alcoa’s application also sought approval to construct the pipeline and ponds despite the fact they were already built.

Alcoa said the pipeline was laid in a conveyor maintenance corridor only accessed by authorised personnel using light vehicles and there had been no leaks.

“Our preference is to continue to transport water containing low concentrations of PFAS out of the catchment when the need arises using the lowest risk method,” the spokeswoman said.

“Alcoa has always acted responsibly and proactively to ensure the drinking water supply is not negatively impacted by water containing low concentrations of PFAS within the Samson Catchment.”

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