TESTING of soil at the Yanchep Volunteer Fire and Rescue Service has shown the presence of per- and poly-fluoroalkyl substances (PFAS), which are found in firefighting foams and other products.
PFAS are highly persistent in the environment, moderately soluble, can be transported long distances (in some cases many kilometres) and transfer between soil, sediment, surface water and groundwater.
The federal Department of Health website says PFAS have been found to have contaminated sites where there has been historic use of firefighting foams containing PFAS.
“Over time, these chemicals have worked their way through the soil to contaminate surface and ground water and have migrated into adjoining land areas,’’ the website said.
“The release of PFAS into the environment is an emerging concern, because these chemicals are highly persistent, have been shown to be toxic to fish and some animals and can accumulate in the bodies of fish, animals and people who come into contact with them.
“However, there is currently no consistent evidence that exposure to PFAS causes adverse human health effects.’’
But in August 2010 two of the chemical – perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) – were added to Annex B of the Stockholm Convention on Persistent Organic Pollutants as it considered both to have significant adverse human and environmental effects.
A Department of Water and Environmental Regulation (DWER) spokeswoman said the current classification of the Yanchep Fire and Rescue Service site under the Contaminated Sites Act 2003 would be reviewed when DWER received the detailed site investigation report from Department of Fire and Emergency Services (DFES).
When preliminary testing at the Yanchep fire station was carried out in September 2017 one of three main PFAS chemicals that concerns investigators was found in the soil there.
The preliminary tested showed a PFOS concentration of between 7.8 microgram per kg to 10 microgram per kg in soil samples.
The testing did not record a result for PFOA or perfluorohexane sulfonate (PFHxS), which are the other two of concern but did not make clear if this was a single sample or result.
The PFOS concentration was enough to have the fire station classified as “possibly contaminated – examination required”.
But this week a DFES asset management assistant commissioner Brad Delavale said random soil sampling that was conducted as part of the preliminary site investigation confirmed the soil was well within environmental and human health safety levels.
“No further testing of the site has been carried out,’’ he said.
“The preliminary site investigation was based on the likely hood of the use of foams containing PFAS.
“No remediation work has been carried out.
“At this stage, there is no need to carry out any remediation work.
“PFAS needs to be ingested to pose any potential risk to health, but the amount that could potentially pose a health concern is still being researched.
“PFAS is a common chemical used in household items such as frying pans and water repellent sprays.’’
The fire station is in the Yanchep light industrial, which means a higher concentration of PFAS is permissible.
The Human Health based guidance value Australia follows is 20mg/kg for PFOS and PFHxS on industrial-commercial sites.
This compares with the values of 0.01mg/kg for residential sites with garden-accessible soil and 2mg/kg for residential sites with minimal opportunities for soil access.
In 2017 DFES said it was allowing firefighters who had used foams containing the chemicals to have their blood tested and was testing for the chemicals at 20 sites in WA.