human health risk assessment - defence

Gingin Satellite Airfield - Comprehensive PFASInvestigation

Department of Defence

Tier 3 Human Health Risk Assessment - Onsite Receptors

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26 November 2018

PFAS 2017-18 Gingin

Depar tme nt of Defe nce


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Gingin Satellite Airfield - Comprehensive PFAS Investigation

Project No: IS219200Document Title: Tier 3 Human Health Risk Assessment - Onsite ReceptorsDocument No.: IS219200-0000-NP-RPT-0006Revision: 3Date: 26 November 2018Client Name: Department of DefenceClient No: PFAS 2017-18 GinginProject Manager: WRAuthor: BGFile Name: C:\users\wrodger\appdata\local\projectwise\jacobs_anz_ie\d0171978\Tier 3 Human

Health Risk Assessment - Onsite Receptors.docx

Jacobs Group (Australia) Pty LimitedABN 37 001 024 095Floor 11, 452 Flinders StreetMelbourne VIC 3000PO Box 312, Flinders LaneMelbourne VIC 8009 AustraliaT +61 3 8668 3000F +61 3 8668 3001www.jacobs.com

© Copyright 2018 Jacobs Group (Australia) Pty Limited. The concepts and information contained in this document are the property of Jacobs. Useor copying of this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright.

Limitation: This document has been prepared on behalf of, and for the exclusive use of Jacobs’ client, and is subject to, and issued in accordance with, theprovisions of the contract between Jacobs and the client. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or relianceupon, this document by any third party.

Document history and status

Revision Date Description By Review Approved

A 02/10/2018 Technical review of draft report BG DC WR

B 04/10/2018 Project Manager review of draft report BG WR WR

0 05/10/2018 Draft issue for review by Department of Defence BG RE WR

1 31/10/2018 Final draft for review by WA Government Agencies DC WR WR

2 22/11/2018 Final draft for review and approval DC WR WR

3 26/11/2018 Issue for Use DC WR WR

Distribution

Revision Date Copy No. Distribution

0 05/10/2018 E-copy Department of Defence, JBS&G

1 31/10/2018 E-copy Department of Defence, JBS&G, WA Government Agencies

2 22/11/2018 E-copy Department of Defence, JBS&G

3 26/11/2018 E-copy For Publication


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ContentsExecutive Summary ................................................................................................................................iii1. Introduction ..................................................................................................................................11.1 Background ....................................................................................................................................11.2 Objectives ......................................................................................................................................11.3 Scope ............................................................................................................................................11.4 Risk Assessment Approach ............................................................................................................22. Site Setting ...................................................................................................................................42.1 General ..........................................................................................................................................42.2 Environmental Setting ....................................................................................................................43. Step 1: Issue Identification ..........................................................................................................83.1 General ..........................................................................................................................................83.2 Data Evaluation ..............................................................................................................................83.3 Preliminary CSM .......................................................................................................................... 104. Step 2: Toxicity Assessment ..................................................................................................... 144.1 General ........................................................................................................................................ 144.2 PFAS and toxicity ......................................................................................................................... 144.3 Toxicity Reference Values ............................................................................................................ 154.4 Adjusted TDIs .............................................................................................................................. 155. Step 3: Exposure Assessment .................................................................................................. 165.1 General ........................................................................................................................................ 165.2 Input Parameters and Equations .................................................................................................. 165.3 Environmental Fate and Transport ............................................................................................... 186. Step 4: Risk Characterisation .................................................................................................... 196.1 General ........................................................................................................................................ 196.2 Risk Characterisation ................................................................................................................... 196.3 Sensitivity Analysis ....................................................................................................................... 206.4 Uncertainty Evaluation ................................................................................................................. 216.5 Revised CSM ............................................................................................................................... 227. Conclusions ............................................................................................................................... 237.1 General ........................................................................................................................................ 237.2 Risks to on-site personnel ............................................................................................................ 238. Recommendations ..................................................................................................................... 249. References ................................................................................................................................. 25

FiguresAppendix A. Risk assessment calculationsAppendix B. Sensitivity assessment


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Executive SummaryThe risks to typical Base personnel at Gingin Satellite Airfield (the Site) from chronic exposure to non-potablewater impacted with per- and poly-fluoroalkyl substances (PFAS) was determined to low and acceptable basedon the findings of this Human Health Risk Assessment (HHRA). This is on the basis that whilst the tap water atthe site does contain levels of PFAS and the water is used for various non-drinking purposes, incidentalexposure from the PFAS is low and acceptable and thus the potential consequences to health are insignificant.

In order to identify potential risk scenarios, an initial conceptual site model was developed based oninvestigations completed at the Site. Plausible pollutant linkages were identified at the Site, with this being aconfirmed source of contaminated non-potable water which is used by Site personnel. Two scenarios wereidentified:

· Scenario 1 – Skin contact and incidental ingestion of water during bathing; and

· Scenario 2 – Skin contact and incidental ingestion of water during kitchen and general domestic activities,vehicle / equipment washdown and irrigation.

In completing this risk assessment, Jacobs understands that the abstracted water at the site is not used fordrinking, with the taps being appropriately labelled as “not for drinking water use”.

An assessment of exposure to PFAS impacted water for the identified on-site personnel in each scenario wascompleted by quantifying estimates of intakes in a series of equations and parameters relevant to the Site. Theestimated intakes of PFAS impacted water considered alongside the toxicity as understood in the currentliterature and guidelines, were used to quantify the risks. The quantified risks were found to be less than thelimit of acceptance (the ratio of the intake to the threshold toxicity reference value was less than 1) andtherefore the initial conceptual site model was consequently revised, with the pollutant linkages now consideredunlikely.

The robustness of the risk characterisation outlined above was demonstrated by noting no substantial change tothe conclusions on completion of a sensitivity assessment by changing the input parameters and associatedassumptions used.

Non-potable water from taps on site contains raised levels of PFAS. Management measures should bedeveloped to reduce risks to a level that is as low as is reasonably practicable. In the long term, considerationcould be given to replacing some of the water supply infrastructure at the Site, however in the short to mediumterm, it is recommended that:

· Non-potable water from on-site taps, Bore 2, any future taps and the on-site abstraction bore within theshallow groundwater continue to be monitored in order to confirm the magnitude and trends of theconcentrations used in this risk assessment.

· An assessment be undertaken in order to review options for upgrading / optimising the operation of theexisting granular activated carbon (GAC) treatment system in order that it more effectively removes PFASprior to circulation of water around the Base

· Continue to implement administrative controls prohibiting the use of tap water at the Base for drinkingpurposes. Base personnel should continue to be provided with bottled water (or similar) instead.

If the concentrations increase substantially, then this risk assessment should be revised. Alternatively, if PFASconcentrations decrease to levels below the drinking water guidelines, and assuming no other changes at theSite, consideration could be given to a reduction and then cessation of monitoring.

Further details of the proposed management measures are included in the PFAS Management Area Plan(PMAP).


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Important note about your report

The purpose of this report is to present the Tier 3 Human Health Risk Assessment (HHRA) in relation topotential onsite receptors prepared by Jacobs for the Department of Defence (Defence) in connection with theComprehensive Investigation of Per- and Polyfluoroalkyl Substances (PFAS) at Gingin Satellite Airfield, WA andsurrounding areas.

This report was produced in accordance with, and is limited to, the scope of services set out in the agreementbetween Jacobs and Defence. That scope of services, as described in this report, was developed with Defence.

All reports and conclusions that deal with subsurface conditions are based on interpretation and judgement and,as a result, have uncertainty attached to them. You should be aware that this report contains interpretations andconclusions which are uncertain due to the nature of the investigations. No study can investigate every risk, andeven a rigorous assessment and/or sampling programme may not detect all problem areas within a site.

This report is based on assumptions that the Site conditions as revealed through sampling are indicative ofconditions throughout the Site. The findings are the result of standard assessment techniques used inaccordance with normal practices and standards, and (to the best of our knowledge) they represent areasonable interpretation of the current conditions on the Site.

The passage of time, the possibility of migration, the manifestation of latent conditions, or impacts of futureevents may require further examination of the project and subsequent data analysis, and re-evaluation of thedata, findings, observations and conclusions expressed in this report.

In preparing this report, Jacobs has relied upon, and presumed accurate, any information (or confirmation of theabsence thereof) provided by Defence and from other sources. Except as otherwise stated in the report, Jacobshas not attempted to verify the accuracy or completeness of any such information. If the information issubsequently determined to be false, inaccurate or incomplete, then it is possible that our observations andconclusions as expressed in this report may change.

Jacobs has prepared this report in accordance with the usual care and thoroughness of the consultingprofession, for the sole purpose described above and by reference to applicable standards, guidelinesprocedures and practices at the date of issue of this report. For the reasons outlined above, however, no otherwarranty or guarantee, whether expressed or implied, is made as to the data, observations and findingsexpressed in this report, to the extent permitted by law. Opinions and judgements expressed in the report arebased on Jacobs’ understanding and interpretation of current regulatory standards and should not be construedas legal opinions.

This report should be read in full and no excerpts are to be taken as representative of the findings. Noresponsibility is accepted by Jacobs for use of any part of this report in any other context. This report has beenprepared on behalf of, and for the exclusive use of, Defence, and is subject to and issued in accordance with,the provisions of the agreement between Jacobs and Defence. Jacobs accepts no liability or responsibilitywhatsoever for, or in respect of, any use of, or reliance upon, this report by any third party.


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List of Abbreviations

Abbreviation Description

AFFF Aqueous film forming foam

CoPC Contaminants of potential concern

CSM Conceptual site model

DER Department of Environmental Regulation (WA Government)

DoEE Department of Energy and the Environment

DoH Department of Health

DSI Detailed site investigation

DWER Department of Water and Environmental Regulation (WA Government)

enHealth Environmental Health Standing Committee

FSANZ Food Standards Australia New Zealand

LOR Limit of reporting

mbgl Meters below ground level

NEPC National Environment Protection Council

NEPM National Environment Protection (Assessment of Site Contamination) Measure 1999 as amended in 2013

PFAS Per- and Polyfluoroalkyl Substances

PFAS NEMP PFAS National Environmental Management Plan

PFOA Perfluorooctanoic acid

PFOS Perfluorooctane sulfonate

PFHxS Perfluorohexane sulfonate

PMAP PFAS management area plan

RAAF Royal Australian Air Force

RSAF Republic of Singapore Air Force

TDS Total dissolved solids

US EPA United States Environmental Protection Authority

WA Western Australia


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1. Introduction1.1 Background

The Department of Defence (Defence) commissioned Jacobs Group (Australia) Pty Ltd (Jacobs) to undertake aHuman Health Risk Assessment (HHRA) of per- and polyfluoroalkyl substances (PFAS) identified ingroundwater and potable water from the Detailed Site Investigation (DSI) for Royal Australian Air Force (RAAF)Gingin Satellite Airfield (the Site) in Western Australia (WA).

The DSI undertaken by Jacobs encompassed an investigation of soil, sediment, surface water, groundwater,tap water and biota (vegetation) to assess PFAS conditions at the Site and surrounding areas (Jacobs,2018a).Prior to the DSI, a preliminary sampling program (PSP) was completed. The results obtained during thePSP and DSI identified that a complete PFAS exposure pathway likely exists with groundwater abstraction anduse at the Site that requires further assessment.

Shallow groundwater at the Site is abstracted and collected from a centrally located well and piped via a watersupply system for use on-site. Raised concentrations of PFAS above the drinking water and recreational wateruse criteria derived from the PFAS National Environmental Management Plan (PFAS NEMP) (HEPA, 2018)were reported in samples of water collected from the abstraction bore. Bottled water is provided for drinkingpurposes, however primary or secondary contact with PFAS contaminated water by Site personnel is likely.These applications include showering / washing, use of water for laundry and washing dishes, as well asirrigation and vehicle / equipment wash down applications.

Based on the identified presence of PFAS in groundwater and the potential PFAS exposure pathways likely tobe present at the Site, this HHRA was prepared to address the uncertainty relating to the risks posed to humanhealth. The objectives, approach and scope of works for this HHRA are outlined in the following sections.

1.2 Objectives

The primary objective for this HHRA, is to determine whether there are risks to the health of Fire Fighters, RAAFand Republic of Singapore Air Force (RSAF) personnel using the Site associated with chronic exposure toabstracted groundwater contaminated by historical use of Aqueous Fire Fighting Foams (AFFF) containingPFAS at the Site. The potential risks associated with on-site personnel using abstracted groundwater from on-site wells were evaluated for:

· Dermal contact during showering and incidental ingestion; and

· Dermal contact and incidental ingestion from washing dishes, laundering clothes, washing equipment andvehicles and law irrigation.

Jacobs notes that this HHRA is not intended to address PFAS risks associated with potential exposure by othermeans, including exposure by construction and maintenance workers to soils in identified source areas at theSite that may contain elevated concentrations of PFAS. In the absence of specific information about thesepotential future activities (including when and where they may occur), the level of uncertainty this presents whenassessing risk means that a HHRA for these scenarios is not recommended at this stage. The requirement tocomplete further activity specific HHRAs will be described in the PFAS Management Area Plan (PMAP) to beprepared for the Site.

Key assumptions and limitations of this HHRA are summarised in Section 1.4.

1.3 Scope

The scope of this HHRA is summarised in Section 1.4 and broadly follows the Government of WesternAustralia’s health risk guidelines (Government of Western Australia Department of Health, 2006) and the riskassessment framework set out herein.


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1.4 Risk Assessment Approach

1.4.1 General

The risk assessment approach, methodologies and calculations adopted for this HHRA are well-established andare consistent with relevant current Australian guidance, including:

· The National Environment Protection (Assessment of Site Contamination) Amendment Measure (NEPM)2013, Schedule B4, Site-specific health risk assessment methodology (NEPC, 2013a); and

· Australian enHealth Council (enHealth Council, 2012b).

Relevant original source material from the United States Environment Protection Agency documents on riskassessment as referenced in Australian guidance, were also consulted.

The approach adopted for this HHRA can be distilled into an assessment of chemicals of potential concern(CoPC) (PFAS), exposure routes (pathways), receptors (on-site personnel) and the potential for the occurrenceof adverse health effects (toxicity). Risk assessments are generally undertaken in a tiered manner with anincreasing level of detail, refinement and generally a decreasing level of uncertainty in the potential risks at aSite. These tiers, as defined by the NEPM, are as follows:

· Tier 1 - A simple or qualitative risk assessment;

· Tier 2 – A screening level assessment where generic published risk-based assessment criteria arecompared to data collected at a site; and

· Tier 3 – A site-specific risk assessment that considers conditions at a site to determine site-specific risks ofharm to health and / or to derive site-specific risk-based assessment criteria (which might be considered asremedial goals).

The HHRA presented in this report is a Tier 3 assessment implemented to assess the risks associated with on-site personnel who may be exposed to groundwater abstracted on-site from shallow groundwater that iscontaminated with PFAS. Each element of the risk assessment will be undertaken in accordance with theframework adapted from enHealth as summarised in Diagram 1.1.

It is also noted that a Tier 2 assessment of shallow groundwater impact identified on the southern boundary ofthe Site is presented in a separate document (Jacobs, 2018b).

Diagram 1.1: Risk Assessment Process

Step 1•Issue identification – evaluate what the nature of the site, what data is available and characterise what’s going

on at the site through preparation a preliminary conceptual site model (CSM) that identifies what thecontamination is, how it will move around the site and who the potential receptors may be.

Step 2•Toxicity assessment – evaluate what the hazard is, what data is available on dose responses and an assessment

of bioavailability based on existing literature.

Step 3•Exposure assessment – evaluate the potential exposure of identified hazards to potential receptors under

plausible scenarios considering pathways, exposure routes and how the receptors will interact with the site.

Step 4•Risk characterisation – quantify the potential health risks that could be posed to identified receptors and

interpreting the significance of the risks informed by evaluation of toxicity of the hazard (step 2) and estimatesof exposure (step 3).


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Consistent with the objectives and approach outlined in Sections 1.2 and 1.4 , the steps outlined in Diagram 1.1.are described further in Section 3 onwards.

This HHRA is based on current risk assessment best practices and tailored to incorporate site-specificconditions and issues and reflects the current regulatory setting and the state of HHRA science. The HHRAbuilds on previous work completed at the Site and forms part of the broader assessment and remedialmanagement process. By characterising potential risks at the Site, further evaluation or implementation ofmanagement or remedial measures for current groundwater exposures can be prioritised.

1.4.2 Risk assessment framework

The steps summarised in Diagram 1.1, rely on quantitatively assessing the magnitude of risk based on standardexposure and risk equations as set out in the NEPM (NEPC, 2013a). The outcome is a numerical assessmentof risk, which is then further examined as part of the uncertainty assessment. The output of the quantitative riskassessment is used as input to a standard risk model based on likelihood of source pathway receptors linkagesand consequence of harm.

The magnitude of the consequence of harm is based on the following (Table 1.1)

Table 1.1: Risk levels and description adopted for this HHRA

Level Description

Low and acceptable More than one order of magnitude below tolerable risk threshold (more than 10 times below theacceptable threshold).

Marginal Up to one order of magnitude below tolerable risk threshold (i.e. up to 10 times below the acceptablethreshold)

Elevated Exceeds tolerable risk threshold

Two conceptual site models (CSMs) were prepared including a preliminary CSM in Section 3 based on potentialrisks given the available data and screening against generic human health criteria and revised CSMincorporating the findings of the HHRA in Section 6.5.


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2. Site Setting2.1 General

The Site is located approximately 55 km north of Perth and is located within the suburb of Yeal, approximately15 km southwest of Gingin town centre in the Shire of Gingin (refer Figure 1).

The Airfield at the Site has been used by RAAF and visiting allied forces on an occasional basis to supplementflying training at RAAF Pearce. The Airfield is used to disperse routine flying training activities away from RAAFPearce and Perth airspace. The Site is also used to support pilot training activities for the Republic of SingaporeAir Force (RSAF). The RAAF operations and facilities at the Site includes firefighting services operated by aDefence contractor, Broadspectrum, an air traffic control tower, crew huts, former caretaker’s cottage andsupporting infrastructure. A summary of basic information relevant to the Site is presented in Table 2.1.

Table 2.1 : Site information summary

Item Information

Defence Property ID 0958

Street Address Airfield Road, Yeal

Locality Gingin, WA, 6503

Municipality Shire of Gingin & City of Wanneroo

State Western Australia

Site Area 706 Hectares (ha)

Approximate coordinates Zone 50J 392015.05E 6518261.57N

Legal Description Lot 1 on Deposited plan 49337

Zoning Rural small holding

Ownership details The Airfield is on Commonwealth land

2.2 Environmental Setting

2.2.1 Topography

The topography across the Site undulates and generally slopes towards the east. However, the landform of thenatural dune system occupied by the Airfield has been substantially modified, regraded and levelled toaccommodate the runway, infrastructure and buildings. Ground elevation generally ranges betweenapproximately 75 - 80 meters Australian Height Datum (mAHD), with the runway at 75 mAHD.

2.2.2 Geology

The 1:100,000 Gingin and Ledge Point geological map (Geological Survey of Western Australia, 2012) showsthat the geology underlying the Airfield and surrounding area comprises Bassendean Sands. The BassendeanSands unconformably overlie Cretaceous and Tertiary strata, and inter-finger to the east with the GuildfordFormation. These formations are described as follows:

· Bassendean Sands - Present over much of the central Perth region, with a maximum reported thicknessof approximately 80 m (Davidson, 1995). The sand is typically pale grey to white and is predominantlymedium grained, moderately sorted, sub-rounded to rounded quartz sand. Fine-grained, black, heavyminerals are commonly scattered throughout the formation. A layer of friable, limonite-cemented sand,colloquially called ‘coffee rock’ often occurs close to the water table.

· Guildford Formation - Consists predominantly of brown silty and slightly sandy clay and interfingers to thewest with the Gnangara Sand and Bassendean Sand. The unit is up to 35 m thick and commonly containslenses of fine to coarse grained, very poorly sorted, conglomeratic and shelly sand at its base, particularly


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in the Swan Valley area. The Guildford Formation is predominantly of fluvial origin and restricted mainly tothe areas of its outcrop.

2.2.3 Hydrogeology

2.2.3.1 General

The Site is located on the Gnangara groundwater system (within the Gnangara Underground Water PollutionControl Area), which covers approximately 2,200 km2 along the coastal plain north of the Swan River to Ginginand east to the Darling Scarp (Department of Water, 2009). The Gnangara Underground Water PollutionControl Area (UWPCA) is proclaimed under the Metropolitan Water Supply, Sewerage and Drainage (MWSSD)Act 1909 and by-laws apply to protect it as a source of public drinking water. The Gnangara UWPCA suppliesdrinking water to the integrated water supply system; including Perth, the Peel region and towns in theGoldfields. The Gnangara Mound comprises four main aquifers that are of relevance to the Site as shown inDiagram 2.1:

· The shallow, unconfined superficial aquifer (the Gnangara Mound);

· The semi-confined Mirrabooka aquifer;

· The deep, mostly confined Leederville aquifer; and

· The deepest, mostly confined Yarragadee aquifer.

In addition to this assessment (which assesses the potential human health risks to on-site personnel), aseparate HHRA has also been prepared that considers the risks to off-site users of groundwater within theGnangara UWPCA (Jacobs, 2018b).

Diagram 2.1: Hydrogeological conceptual model with the relationship between relevant aquifers (Department of Water, 2009)

2.2.3.2 Superficial Aquifer

The superficial aquifer within the Bassendean Sands formation is a major unconfined aquifer used for publicwater supply of the coastal plain north of the Swan River to Gingin and east to the Darling Scarp. The


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Bassendean Sands are highly permeable sandy materials with a hydraulic conductivity ranging between 10 and50 m/day and an average of 15 m/day (Davidson & Yu, 2008).

The superficial aquifer has a maximum thickness of approximately 70 m, but an average thickness ofapproximately 45 m in the northern Perth Region and regionally flows in a westerly direction towards the ocean.However, local groundwater flow often mimics the local topography. Shallow groundwater investigation bores(less than 10 m) installed on Site indicate that local groundwater flows in an easterly and north easterlydirection, consistent with the surface topography, however the vertical extent of such a trend is very limited (i.e.the near surface of the superficial aquifer). The water levels in bores screening the deeper parts of the aquifer(greater than 15 m) are lower and show that groundwater flows in a north-westerly to south-westerly direction,which is consistent with the regional flow direction. Groundwater elevations for the superficial aquifer across theSite are generally about 65 mAHD (about 10 meters below ground level [mbgl]).

2.2.3.3 Mirrabooka aquifer

The Mirrabooka aquifer is hosted within the Poison Hill and Molecap Greensands and the Mirrabooka Memberof the Osborne Formation. The aquifer is a locally important semi-confined to confined aquifer with a variablecomposition ranging from clayey sand to coarse sandstone (Department of Water, 2009). The Mirrabookaaquifer is hydraulically connected to the overlying superficial aquifer and is recharged by downwardgroundwater flow from the superficial aquifer.

2.2.3.4 Leederville aquifer

The Leederville aquifer is a major confined aquifer in the Perth Region and comprises the Leederville Formationand Henley Sandstone Member of the Osborne Formation (Davidson & Yu, 2008). The aquifer is unconfined inthe recharge areas where the aquifer directly underlies the superficial aquifer, and becomes confined over shortdistances by layers of siltstone and shale in the aquifer. The aquifer is around 500 m thick in the vicinity of thesite, although the depth to the aquifer is not confirmed. Groundwater flow is typically in a west to south westerlydirection.

2.2.3.5 Yarragadee aquifer

The Yarragadee aquifer is another major confined aquifer which is more than 2,000 m thick. In the central-northern part of the coastal plain where there are no confining sediments, the Yarragadee aquifer is in directhydraulic connection with the overlying Leederville aquifer. It is noted that WA Water Corporation does notabstract water from the Yarragadee aquifer in the vicinity of the Site.

2.2.4 Groundwater abstraction bores

The nearest WA Water Corporation production bores to the Site are the Pinjar production bores P140 and P145located 7.5 km south-west of the Site boundary and screened within the Leederville aquifer (between 111 - 183mbgl) and superficial aquifer (between 53 – 70 mbgl) respectively. These bores are located in the GnangaraUWPCA and are being used for supplying drinking water to Perth, Peel region and towns in the Goldfields.These bores are licensed to and managed by WA Water Corporation.

In addition to the offsite abstraction bores identified above, there are also two abstraction bores located at theSite itself (although not managed by WA Water Corporation):

· Abstraction bore 1 (Bore 1) is located adjacent to the former Caretaker’s House. This well is understood tointersect the Leederville aquifer (below the superficial aquifer). It was drilled and constructed in 1967 to adepth of 77 mbgl (WA DWER site reference 61607192) and was used intermittently until 2010 when it wasbrought back into service. This well supplies two large water tanks (each about 140 m3) which are used tosupply a network of fire hydrants located across the Site. A hydrant is connected directly to the well and isused to fill fire trucks (allowing regular filling activities to bypass the need to activate the fire pumps thatmay be damaged by what would otherwise be regular use); and

· Abstraction bore 2 (Bore 2) is located within the Pump House compound. The well is believed to intersectthe superficial aquifer. Bore 2 is currently utilised for non-potable applications (including bathing, laundry,


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general site water supply, vehicle / equipment washdown and irrigation). Water from this well was treatedby a reverse osmosis unit and with chlorine prior to circulation around the Site for use and is now alsotreated using a granular activated carbon (GAC) filtration system.

2.2.5 Surface water

There are no permanent surface water features located on or near the Site. Any surface water flows aredirected away from the Airfield into purpose-built drainage channels transecting the Site. Of particular note arethe drainage channels directing surface water flow to the eastern end of the runway, following the naturaltopography of the site.

The nearest hydraulically downgradient groundwater dependent ecosystems is Bindiar Lake locatedapproximately 7.2 km to the west.


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3. Step 1: Issue Identification3.1 General

In accordance with the approach outlined in Section 1.4, the objective of this step is to specify the problem(s) tobe solved and identity the sources, hazards and exposure pathways that are required to understand thepotential risks. These risks relate to the potential for adverse human health effects resulting from potentialexposure to PFAS impacted water at the Site. This information was used to develop a preliminary CSM thatpresents an overview of how identified contamination may be transportable in the environment at the Site, theform this may take, its concentration and what the likely receptors are and how they may be exposed.

The following sections identify the exposure scenarios to be examined, the preliminary CSM and the informationused to inform its development.

3.2 Data Evaluation

3.2.1 General

The results of analysis of on-site tap and abstraction bore samples collected as part of the PSP and DSI wereconsidered for this assessment. Considering the available data, the problem of exposure of on-site personnel toPFAS impacted potable water at the Site is identified by the discussion of CoPC and available data in thefollowing sections.

3.2.2 Selection of CoPC

PFAS are a class of manufactured chemicals that have been used since the 1950s to make products that resistheat, stains, grease and water. PFAS have been used across Australia and internationally in a range ofcommon household products and specialty applications, including in the manufacture of non-stick cookware;fabric, furniture and carpet stain protection applications; food packaging and in some industrial processes.

Defence and other organisations have used AFFF products to suppress liquid fuel fires, in firefighting trainingoperations and in fixed deluge systems for bulk fuel or chemical storage and aircraft hangars throughoutAustralia. From approximately 1970, Defence used an AFFF product called Lightwater, produced by 3M usingan electrochemical fluorination process. This product contained PFAS including PFOS, PFOA and PFHxS.From 2004, Defence transitioned to a product called Ansulite, an AFFF product that is produced through atelomerisation process. Ansulite contains fluorotelomers such as 6:2 fluorotelomer sulfonate (6:2FtS) and 10:2fluorotelomer sulfonate (10:2FtS) which are considered PFAS precursors.

Considering this information, Australian health-based guidance has for PFAS have thus far been derived forPFOA, PFOS and PFHxS and on this basis, only these PFAS have been selected as CoPC for the purposes ofthis assessment. The selection of these CoPC is also based on the following:

· The CoPC have been widely detected in groundwater and tap water at the Site;

· The bore water and tap water are used at the Site for non-potable purposes; and

· The concentrations of the CoPC exceed the investigation criteria (as set out in Table 3.2).

3.2.3 Available data

Water samples collected from six taps located around the Site and one abstraction bore during the PSP andDSI sampling events returned results above adopted screening criteria for the sum of PFOS and PFHxS, andabove the LOR but below adopted criteria for PFOA. The maximum concentration of PFOS and PFHxS togetherwas 0.75 µg/L from sample 0958_POT105, collected from the tap located outside of the Pearce Flying Clubbuilding on 14 February 2018. A summary of the sampling results obtained as part of the PSP and DSI at theSite is presented in Table 3.1.


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Table 3.1: Summary of analytical results from Bore 2 and on-site tap sampling

Location Location ID Sample date PFOS + PFHxS µg/L PFOA µg/L

Bore 2 0958_MW402 03/11/2017

27/03/2018

1.45

0.91

0.05

0.04

Airfield WaterSupplyInfrastructure(Taps)

0958_POT101

(Eastern Leach Field)

03/11/2017

14/02/2018

0.62

0.68

0.02

0.03

0958_POT102

(Air Traffic Control Tower)

03/11/2017

14/02/2018

0.64

0.69

0.02

0.03

0958_POT103

(Crew Huts)

03/11/2017

14/02/2018

0.56

0.74

0.02

0.03

0958_POT104

(Fire House Kitchen)

03/11/2017

14/02/2018

0.51

0.7

0.02

0.03

0958_POT105

(Pearce Flying Club Huts)

03/11/2017

14/02/2018

0.84

0.75

0.03

0.03

0958_POT106

(Former Caretakers House)

03/11/2017 1.03 0.04

Based on the summary of the quality assurance/ quality control conclusions concerning the data reported in theDSI, the data is deemed to satisfy the requirements of the data quality objectives of the investigation programand be adequate for the purposes of this HHRA.

3.2.4 Selected screening criteria

Health criteria for drinking water have been published in the Australian Drinking Water Guidelines (NHMRC &NRMMC, 2011). The health criteria are the same as adopted in the PFAS NEMP (HEPA, 2018a).

These criteria were derived from pharmacokinetic modelling and extrapolation from animals to humans and areconsidered conservative and protective of the respective receptors for the scenarios considered in this HHRA(Department of Health, 2017).

Results of the sampling were compared against the assessment criteria specified in the Australian DrinkingWater Guidelines as reproduced within the PFAS NEMP (HEPA, 2018a) for drinking water and recreationalwater use specified in Table 3.2.

Table 3.2: Health-based investigation criteria for groundwater and surface water

Exposure scenario PFOS + PFHxS µg/L PFOA µg/L

Drinking water – intentional ingestion 0.07 0.56

Recreational water – dermal contact and incidental ingestion 0.7 5.6

The results of applying the criteria outlined in Table 3.2 are summarised in the following section.

3.2.5 Groundwater contamination data

Groundwater sampling was completed at new and existing groundwater wells located across the Site. Towardsthe central source areas, PFAS was reported in shallow groundwater wells within the superficial aquifer atconcentrations above the adopted investigation criteria for drinking water and recreational water use. Thehighest concentrations were observed in wells located in the vicinity of the former fuel farm and powerhouse.

Results from deeper groundwater wells (also within the superficial aquifer) in these source areas indicated asignificant decrease in PFAS concentrations with increased depth, with all samples collected from the deep


IS219200-0000-NP-RPT-0006 10

wells in these areas recording results below adopted assessment criteria and/or respective laboratory limits ofreporting (LOR).

No PFAS was not detected in Abstraction Bore 1 which intersects the Leederville aquifer, however, PFAS wasdetected in Abstraction Bore 2 above the drinking water health-based guidance value with some samples alsoabove the criteria for the recreational use.

The results are summarised as follows:

· Samples from all six taps reported similar concentrations of PFHxS + PFOS, all in exceedance of thedrinking water criteria for the Site. These samples were generally collected over two sampling rounds(except for the former Caretaker’s cottage, for which only one sampling round was performed). Theseconcentrations ranged from 0.51 µg/L to 1.03 µg/L. Five out of the 11 samples collected reportedconcentrations either equal to or greater than the recreational water use criteria. These samples werecollected from the former Caretaker’s cottage (one sample), the former Pearce Flying Club (two samples),the Fire House kitchen (one sample) and the Crew Huts (one samples). All PFOA concentrations werereported below the drinking water and recreational water use criteria;

· Abstraction Bore 2 (installed in the superficial aquifer) reported a concentration of PFHxS + PFOS of 1.45µg/L and 0.91 µg/L during the two sampling rounds. This exceeds the drinking water and recreational wateruse criteria. Samples from nearby shallow groundwater wells generally reported comparable concentrationwith those reported in Abstraction Bore 2 (exceeding both criteria). PFOA concentrations in thesegroundwater wells were also below the assessment criteria; and

· No PFAS was detected in Abstraction Bore 1 above the laboratory LOR (installed in the Leederville aquifer)and used for fire water supply.

3.3 Preliminary CSM

3.3.1 Sources

Considering the selected CoPC, data evaluated in the previous section and the results of the DSI, the followingkey source areas at the Site have been identified as shown in Diagram 3.1 and Figure 2.

· Former fuel storage area,

· Current fire house and adjacent vehicle refuelling area,

· Powerhouse building; and

· Central area where firefighting equipment testing is understood to have occurred.

Groundwater in the superficial aquifer is impacted with PFAS. Groundwater is abstracted from Bore 2 for non-potable purposes at the Site. No significant non-point sources of contamination relevant to potential harm tohuman health have been identified and no significant sources of natural hazardous contamination relevant toPFAS have been identified.

3.3.2 Exposure Point Concentrations

Data was compiled from the previous investigations and the recent DSI completed by Jacobs to identifyExposure Point Concentrations (EPCs). The following is a summary of the understanding of the nature ofexposure points and supporting data that was used to define the EPCs.

Groundwater from the superficial aquifer is extracted from Bore 2 and distributed around the Site, whilegroundwater from Bore 1 abstracted form the Leederville aquifer is used as firewater. Water samples werecollected from six taps located around the Site as well as Bore 2 during a PSP conducted in November 2017, aswell as the DSI conducted between February and April 2018.

All samples collected from on-site taps and Bore 2 reported results above the respective laboratory LOR as wellas the drinking water criteria for the sum of PFOS and PFHxS. Some of the tap samples (and samples from


IS219200-0000-NP-RPT-0006 11

Bore 2) also exceeded the criteria for recreational water use. Results for PFOA were above the respectivelaboratory LOR but below the drinking water and recreational water use criteria.

In 2018, the maximum tap sample concentration (sum of PFOS and PFHxS) was 1.03 µg/L from sample0958_POT106, collected from the former Caretaker’s Cottage during the preliminary sampling in November2017. Due to the limited number of sampling rounds available, maximum detected concentrations ingroundwater or tap water samples were used as EPCs rounded to 2 significant figures. This approach isconsistent with the monitoring recommendations in the Australian Drinking Water Guidelines (NHMRC &NRMMC, 2011). The adopted EPCs are:

· PFOA: 0.04 µg/L at 0958_POT106 being the maximum concentration tap water sample observed; and

· PFOS + PFHxS: 1.03 µg/L at the same location also being the maximum concentration observed in tapwater.

3.3.3 Pathways

Complete and incomplete exposure pathways from the source of contamination to the identified receptors havebeen identified at the Site. Use of the on-site taps for drinking water from Bore 2 was prohibited following theinitial reporting of PFAS in tap samples (prior to commencement of this investigation by Jacobs), however waterremains in use for various non-potable uses. For these uses, complete exposure pathways exist at the site. Anoutline of the identified complete and incomplete pathways is provided in Table 3.3.

Table 3.3: Complete and incomplete pathways

PathwayRelevant to the

Site?CompletePathway

IncompletePathway

Showering (dermal contact, incidental ingestion and inhalation aerosols) Yes ✔ -

Hand washing vegetables and dishes in the kitchen (dermal contact) Yes ✔ -

Laundering clothes (dermal contact) Yes ✔ -

Washing equipment and vehicles (dermal contact) Yes ✔ -

Lawn irrigation (dermal contact) Yes ✔ -

Drinking water (intentional ingestion) Yes - ✔

Inhalation of aerosols during non-potable use of water Yes - ✔

Solid / liquid waste No - -

Food No - -

Non-food consumer products, (e.g. pharmaceuticals) No - -

Surface water No - -

Soil Outside the scope of this HHRA

Air Outside the scope of this HHRA

3.3.4 Receptors and exposure scenarios

Consistent with the objectives and current site uses outlined thus far, current human receptors considered forthe HHRA are summarised in Table 3.4 and identified in the preliminary CSM in Diagram 3.1.

Table 3.4: Current human receptors to be considered in the HHRA

Receptor type Receptor location Key exposure considerations

Site personnel(RAAF, RSAF, etc.)

On-site These individuals are assumed to be present on-site as part of normal operationalrequirements. These individuals are aware that they should not drink water from the tapand drink bottled water. Besides drinking water, they have some knowledge of potentialsafety issues but do not normally take other special precautions. Actual operation tenures


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Receptor type Receptor location Key exposure considerations

and receptor activity will be researched as part of this HHRA, and then used in thedetermination of a typical exposed individual.

Although occasional site visitors may also be exposed, Site personnel (RAAF, RSAF, etc.) are present on-site ata much greater frequency. Visitors are not addressed as a potential receptor. Potentially more sensitivereceptor sub-groups such as children are not considered as these are unlikely to be present for a significantamount of time at the Site. The receptors are assumed to be healthy adults that do not belong to any particularethnic or social group and are gender “non-specific”.

The scenarios considered based on the key exposure considerations are:

· Scenario 1 – Dermal contact and incidental ingestion of water during bathing where the receptor has fullskin exposure; and

· Scenario 2 – Dermal contact and incidental ingestion of water during kitchen and general domesticactivities such as prepping vegetables, laundry, general site water supply, vehicle / equipment washdownand irrigation where the receptor has partial skin exposure of hands and face only.

3.3.5 Preliminary Risk assessment

Considering the components of the preliminary CSM discussed in this section, the complete SPR linkagesidentified are associated with use of abstracted bore water for non-potable applications (including showering,laundry, general site water supply, vehicle / equipment washdown and irrigation).

As shown in the preliminary CSM in Diagram 3.1, a likely likelihood, moderate consequence of harm and highrisk were assigned to each scenario.


IS219200-0000-NP-RPT-0006 13

Diagram 3.1: Preliminary CSM


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4. Step 2: Toxicity Assessment4.1 General

The objective of this step is to identify toxicity reference values (TRVs) for the CoPC. Guidance from enHealthnotes that this generally requires two aspects: hazard identification and dose response assessment. TRVs areconsidered “safe” or not likely to be associated with an adverse human health risk.

In principle, risk assessments would ideally be based on research that has been carried out, peer-reviewed andrecommended by Australian health authorities as appropriate for Australian circumstances. NEPM Schedule B4Table 4 (NEPC, 2013b) summarises the various data sources available, and these are considered in the orderlisted and include chemical-specific assessments by authoritative regulatory agencies.

Two methods are recognised by regulatory authorities for the estimation of toxicological criteria for humans andare applied depending on the mode of toxic action of the compound. These are the:

· Threshold approach or the no-observed-adverse-effect levels (NOAELs) (extrapolation factor approach) fora dose-response relationship; and

· Non-threshold approach for carcinogens where there is always some level of risk at every level of exposureeven if it cannot be directly observed or measured.

For the CoPC considered in this HHRA, the threshold approach has been adopted. In other words, it isassumed for practical purposes that there is a threshold of exposure below which the risk of adverse healtheffects is essentially zero, and no adverse effects will occur.

4.2 PFAS and toxicity

PFAS are absorbed following oral and dermal exposure. Quantitative estimates of the fractional absorption oforally administered PFAS in animals range from greater than 50% for PFHxS to greater than 95% for PFOA andother PFAS. Generally, widely distributed throughout the body, PFAS have been found in human serum. Thereis no evidence of breakdown and has instead been observed to bioaccumulate. PFAS is primarily eliminatedthrough urine with half-lives ranging from hours to years depending on the compound.

To date, the toxicity effects of PFAS are not fully established. Evidence of hepatotoxicity, immunotoxicity anddevelopmental toxicity exists following subchronic and chronic exposures.

No clear link with carcinogenic effects has been established. FSANZ (FSANZ, 2017b) concludes:"Epidemiological studies have not provided convincing evidence of a correlation between PFOS and PFHxSand any cancer type in human beings. Although associations between PFOA and some human cancers havebeen suggested from some epidemiological studies, results have often been contradictory, and a causalrelationship cannot be established with reasonable confidence." This statement was reviewed in detail by theExpert Panel (PFAS Expert Health Panel, 2017), with these conclusions:

· “The evidence does not support PFAS being a major contributor to cancer burden in workers or exposedcommunity populations.

· The evidence on cancer risk is limited, but it is possible there is increased risk of some uncommoncancers, such as kidney and testis.

· The limited evidence relates to PFOA, not PFOS."

The Expert Panel makes a number of recommendations relating to prioritising research into potentialcarcinogenic health effects and PFAS.


IS219200-0000-NP-RPT-0006 15

4.3 Toxicity Reference ValuesThe threshold approach uses a TDI, also termed as a reference dose (RfD), or allowable daily intake (ADI).Conservative estimates of this threshold are made based on an experimentally-determined NOAEL, with theapplication of low-dose extrapolation factors called "safety factors" or "uncertainty factors". The magnitude ofthese factors is dependent on the level of confidence in the use of available data as a basis for extrapolation tothe exposure scenario of the risk assessment. This confidence is dependent on differences in species andduration of exposure, safety of sensitive species and individuals, and the quality of available data (i.e., theweight-of-evidence of the supporting data).

The FSANZ Guide (Department of Health, 2017) recommends TDIs for the oral exposure route of 2.00 x 10-5

mg/kg bw/day for PFOS and 1.60 x 10-4 mg/kg bw/day for PFOA (FSANZ, 2017a). These TDIs are beingadopted at other Defence Sites through the PFAS Investigation and Management Program (Defence, 2017).

The FSANZ Guide presents and reviews the available human epidemiology data for PFAS. FSANZ concludesthat these human data “…are not suitable to support the derivation of TDIs for PFOS or PFOA”. Furthermore,FSANZ concludes that this is consistent with the findings of other regulatory authorities and recommends thatthe TRVs be calculated from toxicological studies completed in laboratory animals (FSANZ, 2017a).

With respect to PFOS, the recommended oral TDI is based on decreased parental and offspring body weightgain in a reproductive toxicity study in rats. A human equivalent dose was calculated based on the modelledserum concentrations at the NOAEL and an uncertainty factor of 30 was applied to account for inter-speciesdifferences in toxicodynamics and differences in the human population. A similar approach was adopted forPFOA. In this case, the TDI was based on developmental and reproductive studies in mice.

The TDI for PFOS + PFHxS was adopted as the TDI recommended for PFOS alone from FSANZ.

4.4 Adjusted TDIs

The following adjustments were made to determine appropriate TDIs for the assessment:

· Oral toxicity factors are based on administered dose and do not take into account the fact that only afraction of the dose is actually absorbed into the body from the gastrointestinal system via the bloodstream.For this reason, a gastrointestinal absorption factor was introduced and conservatively set at 1 (100%), i.e.all of the CoPC is absorbed into the bloodstream,

· As no toxicity data is available for the dermal exposure route for the CoPC, surrogate TDIs were calculatedbased on route-to-route extrapolation from the oral TDI where the oral TDI was also multiplied by thegastrointestinal absorption factor,

· As dermal absorption is poorly understood, the contributions by this exposure pathway is relativelyuncertain. PFOS and PFOA (and by assumption PFHxS) are not thought to be significantly absorbedthrough the skin. As with other HHRAs completed for Defence, a dermal permeability constant of 1x10-6

centimetres per hour was adopted. (Fasano et al., 2005); and

· Background intake for each CoPC was assumed to be 90% of the TDI. Background intake for the generalpopulation in accordance with the NEMP is 80% of the TDI, however given the nature of the careers ofpersonnel working at the site, an increased background take has been assumed(HEPA, 2018).

The adjusted TDIs are presented in Table 4.1.

Table 4.1: Background corrected TDIs per CoPC per exposure route

Exposure Route CoPC TDI (mg/kg-day) Source

Oral PFOS + PFHxS 2.0 x 10-6 (FSANZ, 2017a)

PFOA 1.6 x 10-5

Dermal PFOS + PFHxS 2.0 x 10-6 Oral TDI multiplied by gastrointestinalabsorption factor (1)PFOA 1.6 x 10-5


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5. Step 3: Exposure Assessment5.1 General

The objectives of this step are to characterise the exposure setting, identify potentially exposed populations andpotential exposure pathways, and estimate the exposures to identified human receptors at the Site.

For the purposes of this HHRA, chronic exposure, i.e. a significant part of a lifetime or a lifetime (for humans atleast seven years), has been assumed. Intermittent exposures may occur, but as a conservative approach,chronic exposures are assumed.

A reasonable maximum exposure (RME) is defined as the maximum exposure that is reasonably expected tooccur. For the RME scenario, exposure parameters were selected so that the combination of variables for agiven pathway resulted in an estimate of the RME for that pathway. Under this approach, some variables werenot necessarily at their individual maximum values, but when combined with other variables, resulted inestimates of the RME.

Default and site-specific exposure assumptions were selected to quantify the magnitude, frequency, andduration for each exposure pathway. The parameters for potentially exposed populations were adopted fromenHealth (enHealth Council, 2012b, 2012a) unless stated otherwise.

5.2 Input Parameters and Equations

This HHRA incorporates, where available, site-specific parameters however, as there is uncertainty concerningsome parameters (Section 6.4), assumptions have been made based on professional judgement and defaultvalues specified in relevant guidance documents. Default parameters for most scenarios can be found in NEPM(NEPC, 2013b) and enHealth (enHealth Council, 2012a) and are described herein.

Following US EPA (US EPA, 2004) [equation 3.4], and noting that PFAS are in the main ionised organiccompounds, the dermal absorbed dose per event is calculated using Equation 1. Equation 2 was used toestimate the amount of dermally absorbed water per event and the dermally absorbed dose of water, whileEquation 3 was used to estimate the oral intake of water.

Equation 1 : Dermal absorption of water per event = × ×

Equation 2 : Dermally absorbed dose of water = × × × ×

×

Equation 3 : Oral intake of water ( ⁄ ) = × × ×

×

Where:

DAevent = Absorbed dose per event (mg/cm2 event)

Kp = Dermal permeability coefficient of compound in water (cm/hour)

Cw = Concentration of CoPC in water (mg/cm3)

tevent = Event duration (hour/event)


IS219200-0000-NP-RPT-0006 17

DAD = Dermally absorbed dose

EV = Event frequency (events/day)

ED = Exposure duration (years)

EF = Exposure frequency (days/year)

SA = Skin surface area available for contact (cm2)

BW = Body weight (kg)

AT = Averaging time (days). For non-threshold effects, AT = 70 x 365 days/year.

IR = Ingestion rate (litres/day)

The input parameter Cw is the concentration of CoPC available for uptake at the exposure point. The maximumconcentrations of PFOA and PFOS + PFHxS detected in tap water samples were adopted for parameter Cw.

The receptors were assumed to undertake regular activities and behaviours at the Site. Acute behaviours werenot considered. The Site activity information was assumed to represent “normal” site conditions representing theRME. Input parameters adopted for the model are summarised in Table 5.1.

Table 5.1: Input Parameters for dermal and incidental ingestion exposure

Parameter Symbol Value Units Reference Notes

General Receptor Input

Body weight BW 78 kgenHealth2012

Average for male and female combined body weight(Table E1)

Body height BH 169 cmenHealth2012

Average for male and female combined height (Table E1)

Exposurefrequency

EF 261 events/year -Assumes working 5 days per week for 8 hours a day and4 weeks leave and the event frequency.

Exposure duration ED 10 years - Professional judgement

Averaging timeperiod (non-carcinogens)

ATNC 3650 days - Professional judgement - ED*365 (for non-carcinogens)

Event frequency EV 1 events/day - Professional judgement

Event duration t_event 0.27 hours/eventenHealth2012

95th percentile for non-age specific shower duration(Table 9)

Mean total bodysurface area

TSA 19,017 cm2

AEFGenHealth2012

Calculated from body height and body weight parametersusing the Du Bois and Du Bois (1989) model as per USEPA Exposure Factor Handbook (2011)

Fraction absorbedfrom water

FA 1 - - Assume all absorbed

Fraction ingested FI 1 - - Assume all ingested.

Scenario 1 Specific Inputs: Dermal contact and incidental ingestion of water during showering

Area of skinexposure

SA 19,017 cm2 - Assume whole body during bathing/showering


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Parameter Symbol Value Units Reference Notes

Water ingestionrate

IR 2.8E-03 L/dayAEFGenHealth2012

Average water ingestion rate for male plus female whileswimming (21 mL/hour). As this data is for swimming, thisvalue is halved to consider showering only. This value isthen multiplied by the number of events per day (Table4.6.1).

Scenario 2 Specific Inputs: Dermal contact and incidental ingestion of water during kitchen activities, laundry, general sitewater supply, vehicle / equipment washdown and irrigation

Area of skinexposure

SA 48 cm2 - Assume only face and hands exposed

Water ingestionrate

IR 2.8E-037 L/day - 10% of scenario 1 based on professional judgement

CoPC specific input parameters

PFOAConcentration

Ci 4.00E-08 mg/cm3 JacobsDSI, 2018 Jacobs DSI, 2018, maximum potable tap sample

concentrations, converted from µg/L to mg/cm3.PFOS + PFHxSConcentration

Ci 1.03E-06 mg/cm3 JacobsDSI, 2019

PFOA TDI(backgroundcorrected)

Ci 1.60E-04mg/kgbw/day

FSANZ,2017 FSANZ 2017, based on toxicity studies on mice (page 1

of hazard assessment report) with adjustment forconsideration of backgroundPFOS + PFHxS

TDI (backgroundcorrected)

Ci 2.00E-05mg/kgbw/day

FSANZ,2017

PFOAPermeabilityCoefficient

kpi 1.00E-06 cm/hourFasano etal. 2005

Calculated from undertaking rat and human epidermal invitro experiments with ammonium perfluoroocotonate.

PFOS + PFHxSPermeabilityCoefficient

kpi 1.00E-06 cm/hourFasano etal. 2005

Calculated from undertaking rat and human epidermal invitro experiments with ammonium perfluoroocotonate.

5.3 Environmental Fate and Transport

The fate of chemicals in the environment is controlled by a combination of three groups of factors including:

· The prevailing environmental conditions such as temperatures, flows and accumulations of water and itscomposition,

· The inherent properties of the chemicals which influence partitioning and reaction tendencies, i.e., how fastthe chemical is eventually destroyed by conversion to other chemical species; and

· The patterns of use of the chemicals.

For this HHRA, the concentrations used in the exposure assessment and adopted as EPCs have been directlymeasured during the PSP and DSI rather than having been modelled.


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6. Step 4: Risk Characterisation6.1 General

As the CoPC are considered to be non-carcinogenic, it is assumed that there is a level of exposure below whichit is unlikely for sensitive populations to experience health effects. A simple ratio of estimated intake over TRV(or acceptable intake) is referred to as the hazard quotient (HQ) as per Equation 4. (NEPC, 2013b)

Equation 4: Hazard quotient

=

Combined cumulative or antagonistic risks present several complexities and are, in general, poorly understood.Cumulative risks are addressed by summing the calculated risks or HQs on the assumption that the modes ofaction of the CoPC are similar. This summation is referred to as the hazard index (HI).

In cases where the estimated exposures or risks are less than or equal to the acceptable level (HQ or HI of 1), itis concluded that no observable adverse health effects are expected to occur. When predicted exposures orrisks are above an HQ or HI of 1, this may indicate the potential for adverse effects in sensitive individuals or insome of the exposure scenarios considered. In these cases, the evaluation of HQs and the HI is importantbecause both the exposure estimation procedures and the toxicological criteria are based on a series ofconservative assumptions. A certain level of overestimation of risk is inherently built into the risk assessmentprocess. For example, in cases where there is considerable uncertainty in the data such as the determinationof toxicological criteria, a conservative dose-response extrapolation model is used to derive the toxicologicalcriterion to ensure the protection of human health.

6.2 Risk Characterisation

Based on the assumptions, site-specific information and equations summarised in Section 5.2, intakes of theCoPC via dermal and oral routes were quantified (Appendix A.2 ). The HIs and HQs were then calculated basedon these estimated intakes for both scenarios as summarised in Table 6.1.

Table 6.1: Risk characterisation calculations

Parameter

Route of Exposure

Dermal Oral Dermal Oral

Scenario 1 Scenario 2

Intake (mg/kg day)

PFOA 1.07x10-14 NOTE 1 1.03x10-9 1.07x10-14 NOTE 1 1.03x10-16

PFOS + PFHxS 2.753x10-13 NOTE 1 2.64x10-8 2.75x10-13 NOTE 1 2.64x10-15

Hazard Index

PFOA 1.16x10-7 6.41x10-5 4.74x10-15 6.41x10-12

PFOS + PFHxS 2.39x10-5 1.32x10-2 1.22x10-13 1.32x10-9

Hazard Quotient

Sum of hazard indexes 2.40x10-5 1.33x10-2 6.13x10-8 1.33x10-9

NOTES:

1. Estimated intake for dermal route is the dermally absorbed dose.


IS219200-0000-NP-RPT-0006 20

All calculated HQs as per Table 6.1 are less than 1 and therefore the estimated risk to personnel at the Siteposed by using water abstracted from on-site bores for non-potable water uses including showering, laundryetc. is deemed low and acceptable.

6.3 Sensitivity Analysis

A sensitivity analysis was completed for Scenario 1 to identify the most significant sources of uncertainty in therisk estimates. On this basis, the analysis only focuses on on-site personnel bathing and was conducted byvarying one input parameter at a time between a reasonable minimum and maximum value and assessing whateffect this had on the risks for each CoPC.

The result of the sensitivity analyses are shown in Appendix B where Table B.1 outlines the inputs that werevaried under different scenarios and Table B.2 to Table B.6 summarise the results based on variation of one ofthese parameters at a time.

The results of the sensitivity analyses show that there are a number of key parameters / assumptions that causeuncertainty in the calculation of the estimated intakes and HIs. The following parameters were examined:

· Body weight

Body weight varies between individuals and is one factor that leads to uncertainty in estimates of intake.The adopted body weight for the HHRA of 78 kg is the average non-gender specific average weightreferenced by enHealth. Coupled with body weight is also body height and therefore skin surface area.Body weight and body heights for minimum, central and maximum scenarios were used to calculateproportional changes in skin surface area. The minimum and maximum parameters for body weight andheight were extracted from enHealth guidance. The sensitivity analysis shows that increases in weight,height and skin surface area, decrease risk and as the weight tends towards a lighter body weight, heightand skin surface area, then the HQ tends towards the acceptance goal of 1.

· Exposure frequency

The calculations are based on the assumption that personnel work 5 days per week for 8 hours a day with4 weeks leave and an event frequency of one exposure event per day. The total number of events per yearis 261. A part time worker working at the Site 2 days per week and a full-time worker working every day ofthe year with two exposure events per day were used as the minimum and maximum scenariosrespectively. The sensitivity analysis shows the link between event frequency and risk, where limiting thefrequency of events reduces the corresponding risk. The analysis shows the HQ approaches yet remainsbelow the acceptance goal of 1.

· Event duration

The calculations are based on the assumption that personnel have 16 minute showers as per the 95 th

percentile non-age specific shower duration referenced by enHealth. Half and double this event durationwere used as the minimum and maximum scenarios respectively. The sensitivity analysis shows the linkbetween event duration and risk, where limiting the frequency of events reduces the corresponding risk.The analysis shows the HQ approaches yet remains below the acceptance goal of 1.

· Water ingestion rate

The calculations for the oral exposure route are based on the assumption that on-site personnelincidentally ingest 2.8 mL of water per showering event based on halving enHealth referenced estimatesfor non-gender specific water ingestion rates from swimming. Half and double this event duration wereused as the minimum and maximum scenarios respectively. The sensitivity analysis shows the linkbetween water ingestion rate and risk, where limiting the ingestion rate reduces the corresponding risk. Theanalysis shows the HQ approaches yet remains below the acceptance goal of 1.

· Concentration of CoPC

The adopted concentrations of PFOA and PFOS + PFHxS in water are the maximum concentrationsobserved at the site in tap and abstraction bore samples. Half and double this event duration were used asthe minimum and maximum scenarios respectively. The sensitivity analysis shows the link between CoPC


IS219200-0000-NP-RPT-0006 21

concentration and risk, where lower concentrations reduces the corresponding risk. The analysis shows theHQ approaches yet remains below the acceptance goal of 1.

6.4 Uncertainty Evaluation

As it is not possible or practical to fully describe current and future conditions that influence the nature ofpotential risks, HHRAs require the use of assumptions, judgments, and potentially imperfect data to varyingdegrees. These variables result in uncertainties in the final estimates of risk. The parameters used in the HHRAare characteristically conservative and tend to over-estimate potential site-related risks. An evaluation of thequalitative and the inherent and site-specific uncertainties associated with the HHRA are discussed in thissection. Sources of uncertainty in the exposure assessment include:

· Data evaluation,

· Toxicity assessment,

· Exposure scenarios; and

· Risk characterisation.

Each of these sources of uncertainty are described in Table 6.2. Given the tendency for the assumptionsdescribed below to overestimate both exposure and toxicity, it is considered very unlikely that the overall riskcharacterisation resulted in underestimated potential health risks.

Table 6.2: Summary of uncertainty evaluation

Source of PotentialUncertainty

Potential Risk ofUncertainty

Nature ofPotential Risk

Comments

Data Evaluation

Representativenessof data

Low Over tounderestimate

The investigation work completed by Jacobs was done so in accordanceand agreement with the data quality objectives established for theinvestigations. The integrity and representativeness of the data isconsidered to be adequate for the purposes of this HHRA based on thequality assurance/ quality control analyses and conclusions presented inthe DSI for the field program and the laboratories (Jacobs, 2018a).

Toxicity Assessment

Derivation of TRVs Low Overestimate TRVs adopted in this HHRA are inherently conservative as they are set atlevels an order of magnitude lower than the lowest known effect level. Thisensures that TRVs are set at levels where there is a reasonably highdegree of certainty that no effect will occur (i.e., to the NOAEL). Thus,exceeding the toxicological criterion does not mean that adverse effects willoccur, rather it means that the safety factor beyond the no-effect exposureis somewhat reduced.

The TRVs selected are more conservative than those used in Australia toderive health-based screening levels. Selection of these more conservativevalues is considered prudent as it is acknowledged by NEPC that thevalues selected for Australian guidance have a degree of uncertainty.

Exposure Assessment

EPCs Low Underestimate The maximum concentration from the data set was adopted as the EPC foreach CoPC. This is deemed to provide a RME for the HHRA. If a meanconcentration was utilised, then an underestimate of risk would beconsidered likely.


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Source of PotentialUncertainty

Potential Risk ofUncertainty

Nature ofPotential Risk

Comments

Receptorcharacteristics

Low Overestimate The assumptions made relating to the characteristics of the identifiedreceptors are considered to tend to be towards the high end of likelyvalues. The potential overestimation associated with the assumptionsmade is considered reasonable.

Exposureassumptions

Low Overestimate Exposure assumptions tended to be towards the average of likely valueswith respect to event frequencies and durations. The potentialoverestimation associated with the assumptions made is consideredreasonable.

Risk characterisation

Risk estimation Low Overestimate As described above, exposure assumptions tend to be towards the highend of likely values. The high-case estimate employs a series of individualworst-case assumptions, applied one after another, introducing a repetitiveinput parameter selection bias. The high-case estimates when combinedrepresent a worst-case scenario.

6.5 Revised CSM

Based on the findings of the exposure assessment, risk characterisation, sensitivity analysis and uncertaintyevaluation, the preliminary CSM presented in Section 3.3 was refined and the risk rankings given to eachexposure route revised.

The risk rankings for all the identified potential exposure routes were revised to low. Though the estimated riskassociated with each has been deemed negligible based on the adopted likely scenario, the sensitivity analysisidentified increasing and decreasing key parameters causes the HQ to approach the bounds of acceptablelimits. Considering the preliminary CSM in Diagram 3.1, the revised CSM recognises the following:

· Revision of the consequence of harm from moderate to negligible results in a medium risk. This revision isbased on the estimated risk from the HHRA, in the form of the HQ, being below the acceptable limit,

· The sensitivity of the estimates to changes in the input parameters and assumptions demonstrates that theestimated risk remains below the acceptable limit despite considering assumptions deemed to be moreconservative or otherwise; and

· The assumptions, judgments, and data used for the risk estimates are considered to be adequate for theintended purpose.


IS219200-0000-NP-RPT-0006 23

7. Conclusions7.1 General

Details and findings relating to each step of the HHRA process are provided in the Appendices of this report andshould be read in conjunction with the following summary of the key findings of the risk assessment.

The scope of this HHRA was limited to assessing the potential risks related to potential for adverse humanhealth effects resulting from potential chronic exposure to PFAS impacted non-potable water at the Site.Australian health-based guidance has for PFAS have thus far only been derived for PFOA, PFOS and PFHxSand on this basis, only these PFAS were selected as CoPC. The identified receptors were on-site personnelincluding Fire Fighters, RAAF and RSAF. Two potential exposure scenarios were considered, namely; dermalcontact and incidental ingestion during showering and dermal contact and incidental ingestion for all other non-potable uses at the site.

Assumptions and site-specific parameters were used to estimate the potential intake of the CoPC for eachreceptor and further, to quantify the risk for comparison against acceptable exposure limits (refer Section 6).Inputs to the HHRA were based on assumptions made with professional judgement and (where possible) withsite specific information (refer Section 5). As part of this risk characterisation, an analysis of the sensitivity of themodel and an evaluation of its uncertainty were undertaken to determine how variation in one input wouldinfluence the estimated intakes and subsequent risk (refer Section 6.3, Section 6.4 and Appendix B).

The following summarises the findings of the estimated risks to identified receptors and the recommendationsbased on these findings.

7.2 Risks to on-site personnel

Overall, the calculated hazard indexes for both exposure scenarios are well below one order of magnitudebelow the level where effects might be observed (Section 6.2), thus consequence is ranked “low andacceptable”; namely “More than one order of magnitude below tolerable risk threshold (more than 10 timesbelow the acceptable threshold).”

The sensitivity assessment and evaluation of uncertainties associated with the risk assessment indicates thatassessment of adverse health effects based on the assumptions made are likely to overestimate actual impactsto human health. However, the findings outlined above are contingent on the conditions of the Site not changingto the extent that the risks could become unacceptable.


IS219200-0000-NP-RPT-0006 24

8. RecommendationsGiven that the tap water does however contain raised concentrations over the drinking water quality objective,further assessment and / or mitigation and management measures to control as low as reasonably practicable(ALARP). In the long term, one option for managing the identified risks would be to replace all or some of thewater supply infrastructure or to install water treatment systems to remove the residual PFAS from the water.Use of water at the site is however limited and restricted. Exposure to PFAS and consequences are negligible.On this basis, Jacobs makes the following recommendations for the short to medium term:

1. Continue to implement institutional controls (such as signage) to prevent site personnel from consuming tapwater for drinking purposes. Alternative drinking water supplies (bottled water) should continue to beprovided by Defence for drinking purposes. [Recommended timing: immediate].

2. Undertake an assessment to review options for upgrading / optimising the operation of the existing granularactivated carbon (GAC) treatment system in order that it more effectively removes PFAS prior to circulationof water around the Base, [Recommended timing: short term].

3. Development and implementation of an ongoing monitoring plan (OMP) for the Site that should includeprovision for continued periodic sampling of taps and the existing Abstraction Bore 2. The purpose of thisplan would be to assess PFAS concentration trends over time. Should concentrations in tap samples and /or Abstraction Bore 2 increase significantly, review of the risk assessment should be considered.[Recommended timing: immediately]

It is noted that the PMAP and an accompanying OMP is currently in preparation in parallel to this report. Thesedocuments provide further details of the proposed management actions identified above, as well asrecommendations for ongoing monitoring.


IS219200-0000-NP-RPT-0006 25

9. References

Davidson, W. A. (1995). Hydrogeology and groundwater resources of the Perth region, Western Australia.

Geological Survey of Western Australia, Bulletin 142.

Davidson, W. A., & Yu, X. (2008). Perth regional aquifer modelling system (PRAMS) model development:

Hydrogeology and groundwater modelling. (Hydrogeological record series No. HG 20). Government of

Western Australia Department of Water.

Defence. (2017). PFAS Investigation and Management Program [Government]. Retrieved 14 July 2017, from

http://www.defence.gov.au/ID/PFOSPFOA/

Department of Health. (2017, April). Health Based Guidance Values for PFAS for use in Site Investigations in

Australia.

Department of Water. (2009). Gnangara Groundwater Areas Allocation Plan (Report No. 30). Perth, WA:

Government of Western Australia Department of Water.

enHealth Council. (2012a). Australian Exposure Factor Guide. Canberra, A.C.T.: Dept. of Health and Ageing

and enHealth Council. Retrieved from

http://www.health.gov.au/internet/main/publishing.nsf/content/A12B57E41EC9F326CA257BF0001F9E7

D/$File/Aust-Exposure-Factor-Guide.pdf

enHealth Council. (2012b). Environmental Health Risk Assessment: Guidelines for Assessing Human Health

Risks from Environmental Hazards. Canberra, A.C.T.: Dept. of Health and Ageing and enHealth

Council. Retrieved from

http://www.health.gov.au/internet/main/publishing.nsf/content/A12B57E41EC9F326CA257BF0001F9E7

D/$File/Environmental-health-Risk-Assessment.pdf

Fasano, W. J., Kennedy, G. L., Szostek, B., Farrar, D. G., Ward, R. J., Haroun, L., & Hinderliter, P. M. (2005).

Penetration of Ammonium Perfluorooctanoate Through Rat and Human Skin In Vitro. Drug and

Chemical Toxicology, 28(1), 79–90. https://doi.org/10.1081/DCT-39707

FSANZ. (2017a). Perfluorinated Chemicals in Food. Food Standards Australia New Zealand.

FSANZ. (2017b). Supporting Document 1: Hazard Assessment Report – Perfluorooctane Sulfonate (PFOS),

Perfluorooctanoic Acid (PFOA), Perfluorohexane Sulfonate (PFHxS). Food Standards Australia New

Zealand.


IS219200-0000-NP-RPT-0006 26

Geological Survey of Western Australia. (2012, June). Gingin - Ledge Point (1:100,000).

Government of Western Australia Department of Health. (2006). Health Risk Assessment in Western Australia.

Retrieved from

https://ww2.health.wa.gov.au/~/media/Files/Corporate/general%20documents/Environmental%20health

/Health%20risk%20assesment/Health-Risk-Assessment.pdf

HEPA. (2018). PFAS National Environmental Management Plan. Heads of EPAs Australia and New Zealand,

Government of Western Australia, Department of Water and Environmental Regulation (HEPA).

Retrieved from

https://www.epa.vic.gov.au/~/media/Files/Your%20environment/Land%20and%20groundwater/PFAS%

20in%20Victoria/PFAS%20NEMP/FINAL_PFAS-NEMP-20180110.pdf

Jacobs. (2018a). Gingin Satellite Airfield - Comprehensive PFAS Investigation - Detailed Site Investigation (DSI

No. IS219200-0000- NP- RPT-0003-REV2).

Jacobs. (2018b). Tier 2 Human Health Risk Assessment - Offsite Receptors (Revision 1 No. IS219200-0000-

NP- RPT-0005).

NEPC. (2013a). National Environment Protection (Assessment of Site Contamination) Measure Schedule B3

1999 (as amended) - Guideline on Laboratory Analysis of Potentially Contaminated Soils (Vol. B3).

Canberra, A.C.T.: National Environment Protection Council Service Corporation.

NEPC. (2013b). National Environment Protection (Assessment of Site Contamination) Measure Schedule B4

1999 (as amended) - Site-specific health risk assessment methodology (Vol. B4). Canberra, A.C.T.:

National Environment Protection Council Service Corporation.

NHMRC, & NRMMC. (2011). Australian Drinking Water Guidelines 6 Version 3.5, updated August 2018 (3.5).

Canberra, A.C.T.: National Health and Medical Research Council and Natural Resource Management

Ministerial Council. Retrieved from https://nhmrc.gov.au/about-us/publications/australian-drinking-water-

guidelines

PFAS Expert Health Panel. (2017). Expert Health Panel for per- and poly-fluoroalkyl substances (PFAS).

Retrieved from http://www.health.gov.au/internet/main/publishing.nsf/Content/ohp-pfas-expert-

panel.htm


IS219200-0000-NP-RPT-0006 27

US EPA. (2004). Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual (Part

E, Supplemental Guidance for Dermal Risk Assessment) (No. EPA/540/R/99/005). Washington DC: US

Environmental Protection Agency.


IS219200-0000-NP-RPT-0006

FiguresFigure 1: Site Location

Figure 2: Site Layout

COPYRIGHT: The concepts and information contained in this documentare the copyright of Jacobs. Use or copying of the document in whole orin part without the written permission of Jacobs constitutes an infringementof copyright. Jacobs does not warrant that this document is definitive norfree of error and does not accept liability for any loss caused or arising fromreliance upon information provided herein.

DATA SOURCES© Commonwealth of Australia (Geoscience Australia) 2006 Geodata Topo 250k Series 3; Vicmap Data © State of Victoria 2014;Department of Environment, Land, Water and Planning 23/04/2017.

Á

Á

Á

Á

WANNEROO,CITY OF

GINGIN,SHIRE OF

CHITTERING,SHIRE OF

Robinson St

Timaru Rd

Airfield Rd

Brand Hwy

Lake Bambun

Bindiar Lake

LakeNangar

Loch McNess

Lake MungalaLake Nambung

LakeMuckenburra

MOOLIABEENEE

Gingin

Chandala

GINGIN BROOK

CHAN

DALA

BROO

K

WALLERING BROOK

MOONDA BROOK

CHANDALA BROOK

NULLILLABROOK

WOWRABROOK

LENNARD BROOKBINDOON BRANCH

BREERA BROOK

ROCKY CREEK

GINGIN BROOK SOUTHQUIN BROOK

LegendGingin Boundary

Á Railway StationsRailwayRoadsWatercourseWater BodyGnangara Underground Water PollutionControl AreaLGA Boundary

0 105

kilometres

Document Path: J:\IE\Projects\03_Southern\IS219200\06 Spatial\ArcGIS\20180423_DetailedSiteInvestigation\IS219200_Figure_1_SP_A4.mxd

Figure 1: Site Location Gingin Satellite Airfield Comprehensive PFAS Detailed Site Investigation

IS219200

Date Published: 01 May 2018

± GDA 1994 MGA Zone 50

WANNEROO,CITY OF

GINGIN,SHIRE OF

CHITTERING,SHIRE OF

COPYRIGHT: The concepts and information contained in this documentare the copyright of Jacobs. Use or copying of the document in whole orin part without the written permission of Jacobs constitutes an infringementof copyright. Jacobs does not warrant that this document is definitive norfree of error and does not accept liability for any loss caused or arising fromreliance upon information provided herein.

DATA SOURCES© Commonwealth of Australia (Geoscience Australia) 2006 Geodata Topo 250k Series 3; Vicmap Data © State of Victoria 2014;Department of Environment, Land, Water and Planning 23/04/2017.

!?

!?

BORE_2

BORE_1

Legend!? Abstraction Bore - Existing

Site Features

0 200100Metres

Document Path: \\Jacobs.com\ANZ\IE\Projects\03_Southern\IS219200\06 Spatial\ArcGIS\20180423_DetailedSiteInvestigation\IS219200_Figure_2_SP_A4.mxd

Figure 2: Site Layout Gingin Satellite Airfield Comprehensive PFAS Detailed Site Investigation

IS219200

Date Published: 06 Jun 2018

± GDA 1994 MGA Zone 50

1 00.5 Kilometers

0 4020m

PrimaryLandfill

Vehicle RefuellingArea

Hanger

Hanger

SecondaryLandfill

CaretakersCottage

FormerFuel Farm

Landfill (Off map 600m - see inset)

WashdownPower House

Eastern Leachfield

PearceFlyingClub

Toilet

Asset ServicesYard

WesternLeachfield

Crew HutsChangeRooms Pump House

Fire House

Powerhouse Leachfield


IS219200-0000-NP-RPT-0006

Appendix A. Risk assessment calculationsA.1 Inputs for calculations

The following table outlines the inputs used for the purposes of quantifying intakes via dermal, oral andinhalation exposure routes for the given receptors.

Table A.1: Summary of input parameters for calculations of intake

InputVariables

Symbol Units

Scenario

AssumptionsMinimum

Centralcase

Maximum

Body weight BW kg 60 78 117

Minimum value assumes reference weight foran adult female (Table 2.2.6, enHealth 2012)Maximum value assumes 95th %ile male aged25 to 44 years (Table 2.2.1, enHealth 2012)

Body Height BH cm2 162 169 176

Minimum value based on average body heightof a female (Table E1, enHealth 2012)Maximum value based on average body heightof a male (Table E1, enHealth 2012)

Total surfacearea of skin

TSA cm2 16456 19017 23460

Minimum value based on calculation usingminimum body weight and body heightparametersMinimum value based on calculation usingmaximum body weight and body heightparameters

Exposurefrequency

EF events/year 92 261 730

Minimum value assumes part-time 2 dayworking week for a yearMaximum value assumes working every day ofthe year and bathing twice per day.

Event duration t_event hours/event 0.13 0.27 0.53Minimum assumes half the central caseMaximum assumes double the central case

Wateringestion rate

IR L/day 0.0014 0.0028 0.0056 Minimum assumes half the central caseMaximum assumes double the central case

PFOAConcentration

Cs mg/cm3 2.00E-08 4.00E-08 8.00E-08

Minimum value assumes the minimumconcentration recorded from the samplingprogramMaximum value assumes the maximumconcentration recorded from the samplingprogram

PFOS +PFHxSConcentration

Cs mg/cm3 5.15E-07 1.03E-06 2.06E-06

Minimum value assumes half of the centralcaseMaximum value assumes double the centralcase


IS219200-0000-NP-RPT-0006

A.2 Calculations output

Tier 3 HHRA - On-site Receptors - Model inputs and outputs

Table 1. Summary of the scope fo the human health risk assessment

Table 2. Summary of general receptor inputs

BW 78 kg enHealth 2012 78 kg

BH 169 cm enHealth 2012 169 cm

EF 261 events/year - 261 events/year

ED 10 years - 10 years

ATNC 3650 days - 3650 days

EV 1 events/day - 1 events/day

t_event 0.27 hours/event enHealth 2012 0.27 hours/event

Table 3. Summary of chemical specific inputs

ID VALUE UNITS NOTE ID VALUE UNITS NOTE ID VALUE UNITS NOTE ID VALUE UNITS NOTEPFOA

C1 4.00E-08 mg/cm3 NOTE 1 TDI1 for oral 1.6E-04 mg/kg bw/day NOTE 2 TDI1 for oral 1.6E-05 mg/kg bw/day NOTE 2, 4 kp1 0.000001 cm/hour NOTE 3PFOS + PFHxS

C2 1.03E-06 mg/cm3 NOTE 1 TDI2 for oral 2.0E-05 mg/kg bw/day NOTE 2 TDI2 for oral 2.0E-06 mg/kg bw/day NOTE 2, 4 kp2 0.000001 cm/hour NOTE 3PFOA

C3 2.92E-08 mg/cm4 NOTE 5 TDI1 for dermal 1.6E-04 mg/kg bw/day NOTE 6 TDI1 for dermal 1.6E-05 mg/kg bw/day NOTE 4, 6 Background intake portion of TDIPFOS + PFHxS

C4 7.59E-07 mg/cm5 NOTE 5 TDI2 for dermal 2.0E-05 mg/kg bw/day NOTE 6 TDI2 for dermal 2.0E-06 mg/kg bw/day NOTE 4, 6 BINOTE 1: Jacobs DSI, 2018, maximum potable tap sample concentrations, converted from µg/L to mg/cm3

NOTE 2 FSANZ 2017, based on toxicity studies on mice (page 1 of hazard assessment report) with adjustment for consideration of backgroundNOTE 3: Fasano et al. 2005NOTE 4: Assume 90% of the TDINOTE 5: Jacobs DSI, 2018, Average 95th percentile for potable tap samples (using PROUCL with non-detects), converted from µg/L to mg/cm3

NOTE 6: TDI for dermal route was calculated by multiplying the oral TDI by the gastrointestinal absorption factor

Receptor Identification:

CONTAMINANTS OFPOTENTIAL CONCERN:

APPROACH:

EXPOSURE TYPE:

SCENARIO 1

SCENARIO 2

Non-specific generic Site personnel: Receptor characteristics and activity patterns are based on assumed non-specific generic adults who are Site personnel (RAAF, RSAF, etc.)

PFAS in general and specifically PFOS + PFHxS and PFOA

Threshold toxicity (non-carcenogenic)

UNITS

Average for male and female combined height(Table E1) enHealth 2012

Dermal contact and incidental ingestion from washing dishes, laundering clothes, washing equipment andvehicles and law irrigation

ASSUMPTIONS

Exposure frequency

TDICONCENTRATION

ID

Body weightVALUE UNITS

GENERAL RECEPTOR INPUTS

As scenario 1

As scenario 1

As scenario 1

-

-

Professional judgement

PROJECT DETAILS

Chronic exposure will be assumed

Dermal contact during bathing/showering and incidental ingestion

INPUT VARIABLES

enHealth 2012

-

-

-

Exposure duration

Averaging time period (non-carcinogens)

SCENARIO 2REFERENCE NOTESREFERENCE VALUE

Identification: RAAF GINGIN, IS219200, Tier 3 Human Health Risk Assessment

CHEMICAL

SCENARIO 1NOTESAverage for male and female combined bodyweight (Table E1)

Assumes working 5 days per week for 8 hours a dayand 4 weeks leave and the event frequency.

Professional judgementProfessional judgement - ED*365 (for non-carcinogens)

As scenario 1

PERMEABILITY COEFFICIENT IN WATER

Event frequency

Event duration

TDI - CORRECTED FOR BACKGROUND

CHEMICAL SPECIFIC INPUTS

0.9

Body height Average for male and female combined height (TableE1)

95th percentile for non-age specific showerduration (Table 9)

As scenario 1

Assume same as showering

List of tables:Table 1. Summary of the scope of the human health risk assessment

Table 2. Summary of general receptor inputs

Table 3. Summary of chemical specific inputs

Table 4. Summary of dermal route inputs per scenario

Table 5. Summary of oral route inputs per scenario

Table 6. Summary of calculated risks from dermal exposure

Table 7. Summary of calculated risks from oral exposure

IS219200-0000-NP-RPT-0006 1 of 2

Tier 3 HHRA - On-site Receptors - Model inputs and outputs

Table 4. Summary of dermal route inputs per scenario

-100% % - 0.135% %

-100% % - 0% %

-100% % - 0.120% %

-100% % - 0% %

a00.01545 -

US EPA Exposure FactorsHandbook (2011) 0.01545 -

a10.54468 -


a20.46336 -


TSA

19017 cm2 AEFG enHealth 2012 19016.68309 cm2

SA19017 cm2 -

48 cm2

FA 1 - Professional judgement 1 -

Table 5. Summary of oral route inputs per scenario

IR 2.80E-03 L/day AEFG enHealth 2012 2.8E-07 L/day -

GIA 1 - - 1 - -

FI 1 - - 1 - -

Table 6. Summary of calculated risks from dermal exposure

DAevent UNITS DAD UNITS HI HQ DAevent UNITS AD UNITS HI HQPFOA 1.07E-14 mg/cm2-event 1.86E-12 mg/kg day 1.16E-07 1.07E-14 mg/cm2-event 4.74E-15 mg/kg day 2.96E-10PFOS + PFHxS 2.75E-13 mg/cm2-event 4.78E-11 mg/kg day 2.39E-05 2.75E-13 mg/cm2-event 1.22E-13 mg/kg day 6.10E-08

RESULTSDESCRIPTION:

Table 7. Summary of calculated risks from oral exposure

Intake UNITS HI HQ Intake UNITS HI HQPFOA 1.03E-09 mg/kg day 6.41E-05 1.03E-16 mg/kg day 6.41E-12PFOS + PFHxS 2.64E-08 mg/kg day 1.32E-02 2.64E-15 mg/kg day 1.32E-09

-

Professional judgement

-

NOTESREFERENCE

Median 95th percentile headskin surface area for maleand female (Table E1)

REFERENCEUNITS

Mean body part SA - Legs

VALUEINPUT VARIABLES

SCENARIO 1

NOTES

Assume whole body during bathing/showering




Estimated level of risk is acceptable for this route ofexposure for the receptor based on the assumptions and

variables selected

Estimated level of risk is acceptable for this route of exposure for the receptorbased on the assumptions and variables selected

Assume all absorbed

CHEMICAL

2.40E-05

SCENARIO 1

Estimated level of risk is acceptable for this route of exposure for the receptor based on the assumptionsand variables selected

SCENARIO 2

Estimated level of risk is acceptable for this route of exposure for the receptor based on theassumptions and variables selected

DERMAL ROUTE INPUTS

Calculated from body height and body weightparameters using the Du Bois and Du Bois model asper US EPA Exposure Factor Handbook (2001)


Assume all absorbed

Assume only face and hands exposedMean body part SA - Arms

Mean body part SA - Hands

Fraction absorbed from water

Mean total body SA

Area of skin exposure

AEFG enHealth 2012

-

RESULTSDESCRIPTION:

SCENARIO 1

1.33E-09

SCENARIO 1

NOTES

Average water ingestion rate for male plus female while swimming (21mL/hour). As this data is for swimming, this value is halved to considerbathing only. This value is then multiplied by the no. of events per day(Table 4.6.1).

Assume all ingested.

ORAL ROUTE INPUTS

SCENARIO 2

REFERENCE VALUE UNITS REFERENCE

1.33E-02

NOTES

10% of scenario 1 based on professional judgement

Assume all ingested.

Water ingestion rate

Fraction ingested

6.13E-08

CALCULATED RISKS - DERMAL ROUTE

INPUT VARIABLESVALUE UNITS

Gastrointestinal absorptionfactor Conservatively set at 1 Conservatively set at 1

CALCULATED RISKS - ORAL ROUTESCENARIO 2CHEMICAL

Median 95th percentile hand skin surface area for maleand female (Table E1)

Assume only face and hands exposed

Calculated from body height and body weightparameters using the Du Bois and Du Bois model as perUS EPA Exposure Factor Handbook (2001)

Assume only face and hands exposed

SCENARIO 2

AEFG enHealth 2012

AEFG enHealth 2012Mean body part surface area(SA) - Head

a0 constant

a1 constant

a2 constant

VALUE UNITS

Estimated constant values for ≥ 20 years old (Table7A-1)Estimated constant values for ≥ 20 years old (Table7A-1)

Estimated constant values for ≥ 20 years old

US EPA Exposure Factors Handbook(2011)US EPA Exposure Factors Handbook(2011)US EPA Exposure Factors Handbook(2011)

Estimated constant values for ≥ 20 years old (Table 7A-1)Estimated constant values for ≥ 20 years old (Table 7A-1)

Estimated constant values for ≥ 20 years old

IS219200-0000-NP-RPT-0006 2 of 2


IS219200-0000-NP-RPT-0006

Appendix B. Sensitivity assessmentTable B.1: Summary of inputs varied for sensitivity analysis of scenario 1

Input Variables Symbol Units

Scenario

AssumptionsMin.

Centralcase

Max.

Body weight BW kg 60 78 117

Minimum value assumes reference weight for anadult female (Table 2.2.6, enHealth 2012)Maximum value assumes 95th %ile male aged25 to 44 years (Table 2.2.1, enHealth 2012)

Exposure frequency EF events/year 92 261 730

Minimum value assumes part-time 2 dayworking week for a yearMaximum value assumes working every day ofthe year and bathing twice per day.

Event duration t_event hours/event 0.13 0.27 0.53Minimum assumes half the central caseMaximum assumes double the central case

Water ingestion rate IR L/day 0.00525 0.0105 0.021Minimum assumes half the central caseMaximum assumes double the central case

PFOA Concentration Cs mg/cm3 2.00E-8 4.00E-8 8.00E-8

Minimum value assumes the minimumconcentration recorded from the samplingprogramMaximum value assumes the maximumconcentration recorded from the samplingprogram

PFOS + PFHxSConcentration

Cs mg/cm3 5.15E-7 1.03E-6 2.06E-6Minimum value assumes half of the central caseMaximum value assumes double the centralcase

Table B.2: Sensitivity analysis results for variation in body weight, height and skin surface area for Scenario 1

Variables/Items Symbol UnitsScenario

Minimum Central case Maximum

Dermal route

Estimated dermal intake (PFOA) DAD mg/kg event 2.09E-12 1.86E-12 1.53E-12

Estimated dermal intake (PFOS+PFHxS) DAD mg/kg event 5.38E-11 4.78E-11 3.93E-11

Hazard Index (PFOA) HI - 1.31E-07 1.16E-07 9.55E-08

Hazard Index (PFOS+PFHxS) HI - 2.69E-05 2.39E-05 1.97E-05

Hazard quotient HQ - 2.70E-05 2.40E-05 1.98E-05

Oral route

Estimated oral intake (PFOA) DAD mg/kg day 1.33E-09 1.03E-09 6.84E-10

Estimated oral intake (PFOS+PFHxS) DAD mg/kg day 3.43E-08 2.64E-08 1.76E-08





IS219200-0000-NP-RPT-0006

Table B.3: Sensitivity analysis results for variation in exposure frequency for Scenario 1



Dermal route






Oral route






Table B.4: Sensitivity analysis results for variation in event duration for Scenario 1



Dermal route






Table B.5: Sensitivity analysis results for variation in water ingestion rate for Scenario 1



Oral route







IS219200-0000-NP-RPT-0006

Table B.6: Sensitivity analysis results for variation in concentrations of contaminants for Scenario 1



Dermal route






Oral route






human health risk assessment - defence

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