WA’s environmental regulator says there is a “real and not remote” possibility a pipeline built by a mining company could leak toxic chemicals into a drinking water dam in Western Australia's South-West.
In a ‘prevention notice’ issued on Thursday, WA’s Department of Water and Environmental Regulation (DWER) said Alcoa had built the pipe as part of a PFAS treatment plant at its Willowdale bauxite mine, about 130km south of Perth.
Per-and poly-fluoroalkyl substances, or PFAS, has been used for firefighting, but have been described as toxic “forever chemicals”, which do not break down and can accumulate in soil, water and human bodies.
The federal government recommends minimising exposure to PFAS while further research into its effects are investigated.
DWER alleged the pipeline over the Samson drinking water supply dam was constructed despite an application for it to be built still being assessed by the department.
It also said the pipe was in contravention of its Public Drinking Water Supply Protection Policy and did not meet standards “to prevent the release of PFAS to soil, groundwater or surface waters”.
Inspectors from the department visited the mine last Thursday and found the pipeline was "likely to contain PFAS contaminated wastewater".
“The PFAS pipeline has been constructed through locations where it can easily be damaged by site equipment and vehicles and its integrity compromised,” the prevention notice reads.
“I consider that a release of PFAS contaminated water through pipeline joints or loss of pipeline integrity to be a real and not remote possibility and that such an event will cause emissions which will cause a direct or indirect alteration of the environment to its detriment or degradation or to the degradation of an environmental value.”
Alcoa was ordered to stop operating the pipeline, purge it with clean water into a separate dam at the facility, and provide samples of water from the pipeline for DWER analysis.
The company then has 28 days to remove the PFAS contaminated water to a waste disposal facility.
"This notice relates to a complaint received by the department on 23 February 2023, alleging Alcoa has constructed and is operating infrastructure being assessed in its current works approval application," a DWER spokesperson said in a statement.
"DWER is continuing to investigate the matter."
In a statement, Alcoa said it had been working to address PFAS contamination issues at the mine for four years.
"PFAS traces were unknown to us until 2019 as the manufacturer-supplied information about the fire suppressant we were using at our mining operations did not identify the presence of these chemical compounds," a spokesperson said.
"When our own investigation uncovered this issue, we acted promptly to address the matter and notify the Department of Water and Environmental Regulation.
"We undertook a full risk assessment on the best way to quickly and effectively remove and treat the PFAS affected water.
"Using a sealed and monitored pipeline to transport the water was deemed safer than trucking."
"We informed DWER that we would commence priority works on the construction of water storage facilities and pipeline to mitigate potential risks ahead of last winter.
"The pipeline was used for a short time in 2022 and has not been used since. It is located in a maintenance corridor that can only be accessed by authorised personnel using light vehicles."
The company said there had been no leaks from the pipeline, and that it would work with DWER to address the notice.
Other dam under scrutiny
It comes after the state government recently met with Alcoa to address concerns that contaminated runoff from a bauxite mine near the Serpentine Dam, which supplies drinking water to Perth.
Premier Mark McGowan and senior government ministers made "clear to the company that risks to catchment water need to be appropriately managed", according to the state government.
Alcoa's vice president of operations, Rob Bear, told ABC Radio Perth last month the company was working to meet the state government's risk management requirements.
"We have never negatively impacted the drinking water supply for Perth and we remain committed to programs that will ensure that remains the case," he said.
