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June 2017
RAAF Base Darwin Community Update Factsheet
PFAS Investigation & Management Program
Background to the Investigation
In March 2017, Defence engaged Coffey, an independent
environmental consultant, to conduct a detailed
environmental investigation into the presence of per- and
poly-fluoroalkyl substances (PFAS) on, and in the vicinity
of, RAAF Base Darwin (the base).
The investigation is part of Defence’s review of a number
of its sites around Australia that used legacy fire-fighting
foams containing PFAS.
Defence has a history of using legacy Aqueous Film
Forming Foam (AFFF) for emergency firefighting situations
and for firefighter training. In 2004 Defence commenced
phasing out use of legacy AFFF containing
perfluorooctane sulfonate (PFOS) and perfluorooctanoic
acid (PFOA) as active ingredients. The AFFF now used by
Defence is a more environmentally safe product.
About per- and poly-fluoroalkyl substances (PFAS)
PFOS, PFOA and Perfluorohexane Sulfonate (PFHxS)
belong to a group of chemicals known as per- and poly-
fluoroalkyl substances (PFAS).
AFFF containing PFOS and PFOA as active ingredients
were once used extensively worldwide and within Australia
because of their effectiveness in fighting liquid fuel fires.
PFHxS was also commonly found in the legacy AFFFs as
an impurity in the manufacturing process.
PFAS have been used in Australia and around the world in
many common household products and specialty
applications, including non-stick cookware, fabric, furniture
and carpet stain protection applications and food
packaging.
As a result, most people living in the developed world will
have levels of PFAS in their body.
PFAS are emerging as a contaminant of concern around
the world because the substances persist in the
environment.
Objective of the Investigation
The objective of the environmental investigation is to
identify the nature and extent of PFAS in the environment
from legacy AFFF use at the base and any potential risks
to people or the environment. The understanding of these
potential risks will assist in developing mitigation strategies
to minimise exposure.
The detailed environmental investigation is being
conducted in accordance with the National Environmental
Protection (Assessment of Site Contamination) Measure
1999 (NEPM) and will take approximately 12 months to
complete.
The three main stages to the detailed environmental
investigation include:
Investigation Stages
Stage One: Preliminary Site Investigation (PSI) The Preliminary Site Investigation (PSI) has now been
completed. This stage involved a historical review of AFFF
use and storage to identify on-base sources, develop an
understanding of migration pathways of PFAS from the
source and identify potential receptors.
Sources: where and when legacy AFFF was used Pathways: how PFAS moves in the environment and the possible exposure to people and the environment Receptors: people and the environment that may possibly be exposed to PFAS
STAGE 2
STAGE 3 (if required)
completed STAGE 1Preliminary Site Investigation
Detailed Site Investigation
Human Health and Ecological Risk Assessment
June 2017
Stage One: Preliminary Site Investigation (PSI) continued… Information for the PSI was sourced from previous reports,
interviews with current and former site personnel and
information about regional geology, aquifers and site uses.
The findings of the PSI have been used to develop a
conceptual site model (see below), which identifies
sources of contamination, pathways for migration and
potential receptors exposed to PFAS. The source-
pathway-receptor connection can be presented graphically
(see next page), and is a way of displaying the current
understanding to build on throughout the investigation.
The Investigation Area (IA) has been defined using the PSI
findings that outlined where contamination may potentially
be present, or where further investigation is required to
conclude the extent.
The IA indicates where the sampling effort will be focused
within the second stage of the investigation, the detailed
site investigation (DSI).
The boundaries of the IA have been drawn where there
are geological or water flow reasons for not suspecting
contamination, and/or where existing results confirmed no
detectable concentrations of PFAS.
Graphical Conceptual Site Model – RAAF Base Darwin
June 2017
Stage Two: Detailed Site Investigation (DSI)
The Detailed Site Investigation (DSI) involves on and off-
base sampling of soil, sediments, groundwater, surface
water, plants and animals to build on the PSI information
and characterise the nature and extent of contamination.
Off-base groundwater will be assessed using existing
government bores, private bores (where appropriate
approval is obtained) and newly installed groundwater
monitoring wells.
Soil and sediment sampling will be focused on source
areas on-base and creek beds where residual
contamination may be impacting water or ecology in
contact with sediments.
Limited plants and animal testing will be conducted
targeting aquatic species and home-grown produce to
inform the need for a Human Health and/or Ecological Risk
Assessment.
Investigation Area (IA)
June 2017
RAAF Base Darwin Community Update Factsheet
PFAS Investigation & Management Program
Water use survey
Water use surveys are being used to understand how
groundwater and surface water is being used in the
Investigation Area. The survey is voluntary and can be
obtained electronically or hardcopy.
Contact the information line for a copy, or if you
have any questions about the survey.
Government Guidance
The Environmental Health Standing Committee (enHealth)
of the Australian Health Protection Principal Committee
(AHPPC) has released guidance statements relating to
human health.
According to enHealth, there is currently no consistent
evidence that exposure to PFOS and PFOA causes
adverse human health effects. However, because these
substances persist in humans and the environment,
enHealth recommends that human exposure is minimised
as a precaution.
The Commonwealth Department of Health released final
Health Based Guidance Values (HBGVs) for PFAS on 3
April 2017. These HBGVs were developed by FSANZ at
the request of the Department of Health and replace the
interim enHealth guidelines released in June 2016.
Defence will adopt the final HBGVs in all its environmental
investigations including at RAAF Base Darwin.
Keeping the community informed
Defence is committed to regularly updating the community
throughout the investigation. As well as community
information sessions, updates are provided through the
project website, direct mail and information sheets as new
information becomes available.
National PFAS information line
Phone: 1800 365 414
Web: www.defence.gov.au/id/Darwin
Email: [email protected]
Media enquiries should be directed to Defence Media Operations on (02) 6127 1999 or [email protected]
Useful Links
Commonwealth Department of Health PFAS website:
http://www.health.gov.au/internet/main/publishing.nsf/con
tent/ohpr pfas.htm
Department of Health PFAS hotline: 1800 941 180
Health Based Guidance Values information:
http://www.health.gov.au/internet/main/publishing.nsf/cont
ent/ohpr pfasr hbgv.htm
Northern Territory Environment Protection Authority:
https://ntepa.nt.gov.au/waster pollution/compliance/pfasr
investigation
Northern Territory Power and Water Corporation: https://
www.powerwater.com.au/networks_and_infrastruct ure/
water_services/pfas