Mining giant BHP will begin a follow-up drilling program in WA's north-west this month after detecting Per-and-polyfluro Alkyl Subtances (PFAS) in groundwater beneath its former power station in Port Hedland, about 1,600 kilometres north of Perth. 

The concentrations exceeded Australian guidelines for non-potable water. 

The Nelson Point operations lie less than 2 kilometres from residential homes, Spoilbank Recreation Reserve, and adjacent to Port Headlands' historic West End.

The ABC requested groundwater sampling results from BHP, but the data was not provided. 

International Pollutants Elimination Network (IPEN) technical and policy advisor Lee Bell said PFAS was highly soluble and mobile in groundwater. 

"So the problem with PFAS or 'forever chemicals', as they're known, is because they don't break down they can be mobilised quite rapidly by groundwater plumes as they move through the subsurface," Mr Bell said.

"If (BHP) have detected concentrations of PFAS in the groundwater close to the town, then there needs to be public disclosure of how large that plume is and what action will be taken to remediate it."

A lot remains unknown about the potential health impacts of PFAS exposure although it's been linked to increased blood cholesterol, testicular and kidney cancer, and hypertension in pregnant women.  

Despite no public health and safety concerns around PFAS exposure in Australia, WA Health continues to recommend exposure to PFAS be minimised where possible as a precaution. 

'Proactive drilling program'

In two separate letters BHP sent to Port Hedland residents, it said the risk to community health or the environment from PFAS chemicals "appears minimal".

Head of the Civil Engineering School at the University of New South Wales, Professor Stuart Khan said if concentrations had been located close to a residential area, it did not imply there was zero risk.

"In many areas, households will have a private well or a bore in the backyard that they might be using to pump up groundwater," he said. 

"They might be growing crops that they're using for food, tomatoes in the garden, or there might be chickens pecking around in the backyard.

The Department of Water and Environmental Regulation (DWER) understands groundwater in Port Hedland is not used for domestic purposes. 

In a letter drop to Port Hedland residents last month, the iron ore giant said it was interested in understanding any community groundwater use in the local area and would "appreciate if property owners could advise if a bore was in use".

Private bores for domestic and ordinary use, such as watering an area of lawn or garden less than 0.2 hectares, do not require a permit, according to DWER. 

Based on the information available, a spokesperson for DWER confirmed that BHP had not been able to locate any domestic groundwater abstraction bores north of Nelson Point.  

There have been calls for governments and authorities to permanently ban the toxic chemical, which is used in everyday products like food wrapping and non-stick cookware. 

A recent international study, led by the University of New South Wales, found much of the surface and groundwater around the globe, exceeded PFAS safe drinking limits. 

Senior author of the study, Professor Denis O'Carroll said, compared to other countries, PFAS concentrations were regulated at a higher threshold in Australia and drinking water guidelines were constantly being reviewed.  

"All governments assess risk and have different ways of coming up with guidelines which makes it really, really hard to compare them," he said.

DWER does not keep an inventory of the quantity of PFAS around the state but collects data on a "site-specific basis".

Groundwater monitoring at Whaleback Creek

About 360 kilometres south of Port Hedland lies BHP's Mount Whaleback mine, just outside Newman. 

It has been classed as a contaminated site since 2020 after PFAS was discovered in groundwater and soil with monitoring ongoing and a remediation action plan submitted to DWER. 

The toxic residues were historically dumped into landfill.

BHP's Western Australia iron ore business voluntarily phased out the use of PFAS in its operations.