RAAF Base Darwin

Latest updates

Important information for communities around RAAF Base Darwin.

RAAF Base Darwin Interpretive Report - September 2023 (PDF, 58.87 MB)

Remediation and monitoring update - factsheet – August 2023 (PDF, 1.18 MB)

Community consultation session posters – August 2023 (PDF, 2.57 MB)

Community consultation session presentation – August 2023 (PDF, 2.15 MB)

On Monday 28 August 2023, Defence held a community walk-in information session to provide the local community with an update on:

  • remediation and management activities
  • the ongoing monitoring of per- and poly- fluoroalkyl substances (PFAS) on and around RAAF Base Darwin.

The event was attended by the Honourable Matt Thistlethwaite MP, Assistant Minister for Defence, where he met with the local community to hear their concerns.

For questions relating to the past event, contact via defence.omp@aecom.com or 0499 987 959.

Investigations and findings

In November 2018, Defence completed investigations into per- and poly-fluoroalkyl substances (PFAS) contamination on and around RAAF Base Darwin. Defence recognises that the PFAS contamination from RAAF Base Darwin is a significant issue for the local community. Defence is committed to working with the Northern Territory Government to manage, remediate and monitor PFAS contamination in the area.

The investigations found that PFAS is mostly concentrated in areas where firefighting foams were previously used, stored or disposed. These are called source areas. The PFAS in these locations can be found in soil and in water flowing through the source areas. PFAS moves in surface water flowing through drains and creeks or groundwater that flows underground through soil and rock.

Eleven source areas were identified on the base where PFAS was found in soil or groundwater at levels that required further study or action. These were:

  • Former aircraft rescue and firefighting (ARFF) fire station
  • Current fire training area
  • Former fire training area 1
  • Former fire training area 2
  • Former fuel farm 1
  • Former fuel farm 4
  • Former fuel farm 5
  • Former fuel farm 6
  • Hangar 31
  • Wrapped stockpiles, also known as aqueous film forming foam (AFFF) contaminated soil stockpiles
  • Former RAAF fire station.

Human Health Risk Assessment

As part of the investigations, Defence conducted a Human Health Risk Assessment. This assessment measured the PFAS exposure risks to people living, working and undertaking recreational activities within the management area. The assessment found a low risk for the majority of common activities and scenarios assessed. However, the Northern Territory Environment Protection Authority issued precautionary advice recommending that eating fish, shellfish and crustaceans caught from Ludmilla Creek and Rapid Creek should be limited.

More detail on Defence’s risk assessments can be found in the Human Health Risk Assessment factsheet.

Additional investigations

Defence conducted a Mass Flux Assessment that tracks how and where PFAS is moving from source areas and how much PFAS is leaving the base. This study helps determine the best remediation actions to reduce the amount of PFAS leaving RAAF Base Darwin. The investigations found that PFAS mainly moves off base through Rapid Creek.

Remediation and management

The aim of remediation is to minimise PFAS leaving the base, by focusing on the remediation and management of the source areas. Over time this will contribute to the reduction of PFAS in the management area. Defence has a PFAS Management Area Plan setting out the proposed remedial works and other management actions to manage potential risks presented by PFAS.

At RAAF Base Darwin, PFAS was found to be primarily moving through surface water. Ground water discharge to Rapid Creek also contributes to some of the PFAS moving off base. To prevent PFAS moving from the source areas on base, the remedial works focus on treating PFAS in soils and other surfaces such as concrete.

Soil remediation

The following provides an update for each of the major PFAS source areas identified in the investigations:

Former fire training area 1

Investigations at the Former fire training area 1 found it is the largest source of PFAS at RAAF Base Darwin. The soil in this area contains approximately 34 kg of PFAS. A remediation action plan has been prepared for former fire training area 1 to reduce the ability for PFAS to move through groundwater, drains and creeks into the management area.

The remediation consists of removing the contaminated soils in the area. The removed soils will be treated to fix the PFAS in place or processed through a specialised treatment facility off the base. Clean soil will be re-used on base, where the final surface will be smoothed out to allow water to flow across without gathering in one area.

Defence has scheduled these works for completion in late 2023.

Current fire training area

Investigations at the current fire training area found this area contains approximately 11 kg of PFAS. A remediation action plan is currently being developed to reduce the ability for PFAS to move through groundwater, drains and creeks into the management area.

Former ARFF Fire Station

Investigations at the former ARFF fire station found this area contains approximately 28 kg of PFAS. A remediation action plan is currently being developed to reduce the ability for PFAS to move through groundwater, drains and creeks into the management area.

Former fuel farms 4 and 6

Investigations at former fuel farms 4 and 6 found this area contains approximately 6.5 kg of PFAS. A remediation action plan is currently being developed to reduce the ability for PFAS to move through groundwater, drains and creeks into the management area.

Hangar 31 and former fuel farm 1

Defence recently completed remediation works at Hanger 31 and former fuel farm 1. These works included removing the fuel tank and the construction of new drains. It is estimated these works removed approximately 90% of PFAS found in the source area.

Former RAAF fire station and former fuel farm 5

A review of the investigation data found that the amount and movement of PFAS from the former RAAF fire station and former fuel farm 5 are low in comparison to other source areas. Management actions will be considered as part of future development on base.

Ongoing monitoring

Monitoring of PFAS continues through sampling of surface water, groundwater and fish, shellfish and crustaceans. Monitoring helps Defence understand if PFAS contamination is changing over time.

The results are published in an Ongoing Monitoring Interpretive Report and factsheet. Defence will inform the community if changes to the management approach are required.

Monitoring results to date have found no significant changes to how PFAS is moving in the management area. However, the remedial works are expected to reduce PFAS from leaving the base, and over time this will contribute to the reduction of PFAS in the management area.

Recent reports and factsheets

Detailed reports from the PFAS investigation and management are available for download. Appendices to these reports can be found in the document archive. To discuss these reports, contact pfas.enquiry@defence.gov.au.

Document archive

The RAAF Base Darwin document archive contains information that Defence has published about the management of PFAS. This includes:

  • includes older community presentations,
  • investigation reports,
  • risk assessments and
  • factsheets.

Some archived information has been superseded by recent reports and factsheets.

Documents Archive - Darwin (PDF, 284.75 KB)

Last review: 3 August 2023