Richmond RAAF Base PFAS investigation finds chemical plume in groundwater

RUNOFF: A ten-square-kilometre plume of PFAS has been found in the groundwater under the Richmond RAAF base, with runoff into Rickabys Creek. Picture: Geoff Jones
RUNOFF: A ten-square-kilometre plume of PFAS has been found in the groundwater under the Richmond RAAF base, with runoff into Rickabys Creek. Picture: Geoff Jones

AN investigation into PFAS contamination on and around the Richmond RAAF Base has found a ten-square-kilometre plume of the chemical in groundwater.

The PFAS contamination came from the use of legacy firefighting foam at the Base, and this type of foam was phased-out in 2004.

A Department of Defence and AECOM report on the investigation released on Thursday, June 14 identified five sites on the RAAF Base as source areas for the plume.

All major on-site drainage systems were found to contain levels of PFAS above the reporting limit for drinking and detections were also found at locations where surface water discharges from the site, including tributaries to Rickabys Creek and Bakers Lagoon.

Defence hosted a walk-in session for community members at Hawkesbury Central Library, where it explained the findings and what they mean for residents.

Luke McLeod, assistant secretary PFAS Investigation and Management, said there was no evidence of residents using the contaminated groundwater for drinking, and use of groundwater for watering stock and irrigation was found to be limited.

He said over 150 residents were involved in a community water use survey, and none were using bore water as their main source for drinking.

“It’s a good result from the point-of-view of human health,” he told the Gazette.

“More broadly, we’re not finding significant levels of contamination throughout the investigation area.”

Rickabys Creek and Bakers Lagoon were found to have PFAS levels above guidelines for recreational water use - a guidance designed to cover the incidental ingestion of water during recreational activities like swimming - however Mr McLeod said guidelines were designed to be “highly protective” of human health.

He advised locals using Rickabys Creek and Bakers Lagoon for recreation should “take sensible precaution”.

“Unless they were using it every day and swimming or recreating in it for reasonable periods of time such that they were incidentally ingesting over 200mL, then I would just say take sensible precaution - try not to drink significant mouthfuls of the water - but also not to be concerned about the health impact of doing so,” he said.

Samples from the Hawkesbury River, a farm dam, and drains close to the Base and Rickabys Creek, found PFAS concentration below the health-based guidance for recreational use.

The latest community briefing released the findings from the Detailed Site Investigation (DSI), which involved sampling and laboratory analysis of groundwater, surface water, soil and sediment to better understand how PFAS moves on the Base and in the surrounding area.

Sampling involved 89 groundwater samples from new and existing groundwater monitoring wells, analysing 49 soil samples, and analysing 37 surface water samples and 36 sediment samples.

The area to be studied was identified from a review of information on environmental conditions in the area including topography, surface water drainage, hydrogeology and land use.

The next steps in the investigation will be the Human Risk Assessment (HHRA) and Ecological Risk Assessment (ERA), and PFAS Management Area Plan (PMAP).

This will assess potential exposure to PFAS from contact with skin, incidental ingestion of water and recreational use of affected water; potential for bioaccumulation in livestock, poultry, fish and other aquatic organisms; and potential exposure via ingestion of fish caught within the affected area, and fruit and vegetables grown within the area.

Community briefings on the results of these assessments will be held later in the year.

Defence began its environmental investigation into the presence of per- and poly-fluroalkyl substances (PFAS) contamination on and around RAAF Base Richmond in 2016.

For more information about the investigation, call the community hotline on 1800 789 291 or visit defence.gov.au/environment/pfas/Richmond.