Latest updates
Information for communities around RAAF Base Tindal.
As at 26 March 2025, information related to ongoing monitoring results for swimming and fishing locations in Katherine is provided in the 'Ongoing monitoring' section.
Reports
- July 2023 - April 2024 Ongoing Monitoring Report (PDF, 36.77 MB)
- July 2023 – April 2024 Ongoing Monitoring Report Factsheet (PDF, 1.16 MB)
Investigations and findings
In November 2018, Defence completed investigations into per- and poly-fluoroalkyl substances (PFAS) contamination on and around RAAF Base Tindal.
PFAS contamination from RAAF Base Tindal is a significant issue for the local community. Defence is committed to working with the Northern Territory (NT) Government to manage, remediate and monitor PFAS contamination in the area.
The investigations found that PFAS are mostly concentrated in areas where firefighting foams were previously used, stored or disposed of. These are called source areas. PFAS at these locations can be found in soil and in water flowing through the source areas. PFAS move in surface water, flowing through drains and creeks or groundwater that flows underground through soil and rock.
Two source areas were identified on the base where PFAS was found in soil or groundwater at concentrations that required further assessment or action:
- fire training area
- fire station area.
Human Health and Ecological Risk assessments
As part of the investigations, Defence conducted a Human Health Risk Assessment and an Ecological Risk Assessment. These assessments measured the PFAS exposure risks to people living, working and undertaking recreational activities within the management area and to local plant and animal life.
These assessments found that drinking bore water presents an elevated exposure risk at properties where PFAS were detected above drinking water guidelines. These properties have been contacted and are being supplied with alternative drinking water.
More details on Defence’s risk assessments can be found in the Human Health Risk Assessment factsheet and the Ecological Risk Assessment factsheet under the ‘Recent reports and factsheets’ section.
To support reduction of community exposure to PFAS, the NT Government has issued precautionary advice for the consumption of some bushfoods in the Katherine area and also provides advice for eating fish, shellfish and crustaceans from Katherine River (between Donkey Camp Weir and Daly River) and Tindal Creek. For more information, please refer to the Fish and bush food containing PFAS chemicals page.
Additional investigations
Defence conducted a PFAS movement assessment that tracks how and where PFAS are moving from source areas and how many PFAS are leaving the base. Findings from the assessment identified that PFAS were found to primarily move through groundwater. Surface water discharges to Tindal Creek also contributes to some PFAS moving off the base. These findings helped determine the best remediation actions to reduce the amount of PFAS leaving RAAF Base Tindal.
Remediation and management
The aim of remediation is to minimise PFAS leaving the base by focusing on the remediation and management of source areas.
Over time, this remediation will reduce the amount 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.
Most remediation actions recommended in the PFAS Management Area Plan for RAAF Base Tindal are complete. Soil remediation works were completed in November 2024, while groundwater treatment will continue at the 2 on-base water treatment plants.
Fire training area and fire station area
Investigations confirmed that the fire training area and fire station area are the largest sources of PFAS leaving the base.
Both of these source areas have been remediated using a process called soil stabilisation. Soil stabilisation involves digging the contaminated soil out of the source area and treating it with activated carbon to bind the PFAS. This reduces its ability to wash out into stormwater and groundwater. The treated soil is then placed back in the area and covered with a clean layer of topsoil and grass to prevent erosion and minimise exposure to rainwater.
Groundwater remediation
Since 2019, Defence has operated 2 groundwater treatment plants on RAAF Base Tindal to remove PFAS from groundwater and to reduce the amount of PFAS moving off base. These plants have treated over 3 billion litres of PFAS-contaminated groundwater to date.
Managing Katherine’s impacted water supply
PFAS contaminated groundwater has impacted the groundwater used for drinking water in the Katherine area. To address this, Defence works with Power and Water Corporation to treat PFAS-impacted water before it enters the town water supply.
To secure a long-term water supply for Katherine, Defence funded the construction of a permanent groundwater treatment plant in Katherine. The permanent plant can treat up to 10 million litres of water per day. It replaced a temporary water treatment plant that Defence provided in 2017 to remove PFAS from Katherine’s water supply. Power and Water Corporation has been operating the plant since May 2024.
In areas where residents rely on bore water that has been impacted by PFAS, Defence is providing an alternative water supply or rainwater tanks.
Further information for drinking water quality in Northern Territory can be found on the following pages:
- Power and Water website - Drinking water quality page
- Power and Water website - Katherine's Water supply.
Reports for water treatment plant sampling results can be found under Reports.
Ongoing monitoring
Monitoring of PFAS continues on and around RAAF Base Tindal, including the Cossack area, through sampling of surface water, groundwater and aquatic biota. Monitoring helps Defence understand if PFAS contamination is changing over time.
The results are published in an Ongoing Monitoring Report and factsheet. Defence will inform the community if changes to the management approach are required.
Monitoring results for swimming and fishing locations
Defence’s Ongoing Monitoring Program monitors swimming and fishing locations to help Defence better understand where PFAS are moving and the concentration levels in these areas.
Monitoring results are measured against the Drinking Water and Recreational Health Based Guidance Values for perfluorooctanoic acid (PFOA) and sum of perfluorooctane sulfonate and perfluorohexane sulfonate (PFOS + PFHxS).
These guidelines are used to investigate and assess potential human health risks. The nationally agreed figures are developed by Food Standards Australia New Zealand and the National Health and Medical Research Council.
The guidelines are available via the ‘Health-based guidance values for PFAS for use in site investigations in Australia’ page.
The most recent PFAS testing results are in the following table.
| Sample location | Sample date | PFOA result | PFOS + PFHxS result |
|---|---|---|---|
| Katherine River – Low Level Crossing | Oct 2024 | <LOR* | 0.27 μg/L# |
| Katherine River – Stuart Highway Crossing | Jan 2025 | <LOR* | 0.02 μg/L^ |
| Katherine Hot Springs | Jan 2025 | <LOR* | 0.02 μg/L^ |
* Less than the limit of reporting (<LOR). If PFAS are present in the sample, they are too low for the laboratory to measure with any degree of certainty.
# Result is above the guideline values for drinking water use.
^ Result is below health-based guideline values for recreational use and drinking water use.
Recent reports and factsheets
Detailed reports from the PFAS Investigation and Management Program 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.
- October 2024 Community Information Session Factsheet (PDF, 1.01 MB)
- October 2024 Community Information Session Posters (PDF, 5.03 MB)
- October 2024 Community Information Session Presentation (PDF, 4.95 MB)
- PFAS Management Area Plan Update Factsheet (PDF, 3.5 MB)
- PFAS Management Area Plan Report (PDF, 10 MB)
- Human Health Risk Assessment Factsheet (PDF, 2 MB)
- Human Health Risk Assessment - Executive Summary (PDF, 1.5 MB)
- Ecological Risk Assessment Findings Factsheet (PDF, 1.5 MB)
- Ecological Risk Assessment Report (PDF, 7.6 MB)
Water sampling reports
Water sampling reports from the management of water treatment plants are as follows:
- Water Treatment Plant Sampling Results Katherine Power and Water Corporation (PDF, 2.62 MB)
- Water Treatment Plant Sampling Results RAAF Base Tindal Fire Training Area (PDF, 1.47 MB)
- Water Treatment Plant Sampling Results RAAF Base Tindal Fire Station Area (PDF, 1.35 MB)
Document archive
The RAAF Base Tindal document archive contains information that Defence has published about the management of PFAS, including older community presentations, investigation reports, risk assessments and factsheets.
Some archived information has been superseded by recent reports and factsheets.
Documents Archive - Tindal (PDF, 302.88 KB)
Last review: 26 March 2025.
Contacts
pfas.tindal@truenorthcomm.com.au
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