Per- and poly- fluorinated alkyl substances (PFAS) are manufactured chemicals that are used to make products resistant to heat, stains, grease and water.

PFAS have been widely used for more than 50 years in many consumer and industrial products, including carpets, cookware, clothing, food packaging, pesticides, stain repellents, firefighting foams, mist suppressants and coatings.

PFAS are stable chemicals that are resistant to physical, chemical and biological degradation. Because of these properties, PFAS last for a long time and they can be found in humans, animals and throughout the environment in Australia and other parts of the world.

There are many types of PFAS. The PFAS most commonly encountered in the environment and in wildlife are perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). These are also the most studied PFAS due to their frequent occurrence in the environment, persistence and potential for bioaccumulation.

PFAS molecules are made up of a carbon chain with attached fluorine atoms, and a hydrophilic (water soluble) group at one end.

The hydrophilic headgroups make PFAS very soluble in water. Consequently, PFAS can move from soil to surface water or groundwater and then migrate to creeks, rivers and lakes.

PFAS can also be taken up by organisms in contaminated areas and be transferred through the food chain.

Foams containing PFAS (known as Aqueous Film Forming Foams or AFFF) were historically used at airports because of their effectiveness at putting out liquid fuel fires.

At Melbourne Airport these foams have been stored in aircraft hangers for deluge systems and used extensively in training for and responding to firefighting emergencies involving liquid fuels.

The firefighting foams historically used at Melbourne Airport and other airports containing PFAS included commercial products such as 3M LightWaterTM and AnsuliteTM.

These products were used for both operational and training purposes until 2010.

Foams containing PFAS have been stored and/or used at a number of locations within the airport, including the following sites leased by Airservices Australia:

• The current and former fire training grounds located in the north-west corner of the airport.
• The Melbourne Airport Fire Station, Learning Academy Hot Fire Training Ground and Smoke Hut located in the central portion of the airport, to the west of the main north-south runway.
• A Satellite Fire Station and Hangar/Maintenance Area located to the east of the main north-south runway.

Other tenants have stored and/or used the foams in maintenance hangars and the aviation fuel storage depot.

Most people are exposed to low levels of PFAS which is usually from eating food or drinking water with PFAS in it.

Victoria’s Environment Protection Authority states this is unlikely to be harmful to health but recommends that as a precaution, people reduce their exposure to PFAS.

Studies of human populations that have been exposed to PFAS at their workplace or in the environment have not provided definitive or consistent results.

Possible links between PFAS exposure and some health effects have been reported in some studies, but other studies have not identified any effects.

In studies where large doses of PFAS are given to laboratory animals, possible effects on the immune system, liver, reproduction, development and benign (non-cancer) tumours have been identified.

However, PFAS behaves differently in the bodies of animals compared to humans, so effects shown in animals may not occur in humans.

In the environment, PFAS have been shown to have adverse effects on some plants and animals, including fish.

Studies on fish and animals have identified effects on reproductive, developmental and other systems.

The concentrations at which effects have been observed varies between different types and species of organisms.

PFAS can accumulate in the bodies of animals, particularly those that eat fish, such as dolphins, whales, seals, sea birds and polar bears.

Because of the persistence of PFAS, exposure can occur in the environment over long time periods, and concentrations can increase in animals higher up the food chain.

In agricultural settings, livestock may be exposed to PFAS in water, soil and feed, resulting in accumulation in edible tissue or milk.

Agriculture Victoria has advised that there has been no evidence of PFAS affecting the health or production of grazing livestock in Australia.

Melbourne Airport takes the treatment and management of PFAS contamination of its site very seriously and has developed a comprehensive management strategy to manage potential risks.

Soil testing for PFAS has been undertaken at more than 700 locations across the airport

The main sources of PFAS contamination have been identified in areas where PFAS foams were previously used or stored, in the vicinity of the fire training grounds, the Learning Academy Hot Fire Training Ground / Smoke Hut and the Melbourne Airport Fire Station.

Groundwater monitoring wells have been installed and tested in locations on and down gradient of identified potential PFAS source areas.

Wells have also been installed at locations along the down gradient (south- west) airport boundary to identify what concentrations may be migrating beyond the boundary.

Surface water testing has been conducted at a number of locations within and outside the airport for many years as part of our regulatory obligations.

Melbourne Airport has built a dedicated management facility for low-level contaminated soil, which has capacity for up to one million cubic metres of spoil.

This includes an associated water treatment plant, which captures all run-off from the facility, treats it, and removes all contaminants before the water is reused for dust suppression and irrigation.

A second PFAS treatment plant was commissioned in January 2021 and processes base flow water in Arundel Creek before it is discharged back into the creek.