TITLE: COVER IMAGE TOP - GROUNDWATER REMEDIATION AND MANAGEMENT PLAN 2019-2024 BOTANY GROUNDWATER CLEANUP PROJECT DOCUMENT NO. EN1591.61.PR083 ...
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GRAMP 2019-2024 1
GROUNDWATER REMEDIATION
AND MANAGEMENT PLAN
2019-2024
BOTANY GROUNDWATER CLEANUP PROJECT
DOCUMENT NO. EN1591.61.PR083
REVISION 1
26 MARCH 2020
TITLE: COVER
IMAGE TOP
SUBTITLE GOES HERE
DATE
GeneralGRAMP 2019-2024 2
CONTENTS
LIST OF ACRONYMS 4
1 INTRODUCTION 6
1.1 OBJECTIVES 6
1.2 DURATION AND REVIEW 7
1.3 EXCLUSIONS 7
2 BACKGROUND 7
2.1 SUBJECT AREA 7
2.2 PREVIOUS ENVIRONMENTAL ACTIVITIES 8
2.3 REGULATORY HISTORY 9
2.4 CONTAMINANTS OF CONCERN 10
2.5 REMEDIATION STRATEGY REVIEW 11
3 REMEDIATION AND MANAGEMENT APPROACH 13
4 HYDRAULIC CONTAINMENT 14
4.1 CAPTURE ZONE ANALYSIS 14
5 GROUNDWATER AND SURFACE WATER MONITORING 15
5.1 SUMMARY OF 2017-2020 MONITORING PROGRAM’S CONTENT 16
5.2 SUMMARY OF 2020-2024 MONITORING PROGRAM’S CONTENT 17
5.3 REPORTING SCHEDULE 18
5.4 MONITORING PROGRAM REVIEW 20
6 ASSESSMENT OF RISK TO HUMAN HEALTH 20
6.1 CONSOLIDATED HUMAN HEALTH RISK ASSESSMENT 20
6.2 MONITORING 21
6.3 REPORTING 22
6.4 SPRINGVALE DRAIN 22
7 SOURCE AREAS AND ASSESSMENT OF REMEDIATION
ALTERNATIVES 23
GeneralGRAMP 2019-2024 3
8 PROVISION OF BACKUP TO THE GROUNDWATER TREATMENT
PLANT 24
9 COMMUNITY CONSULTATION 24
9.1 OBJECTIVES 24
9.2 ACTIVITIES 25
10 REFERENCES 26
GeneralGRAMP 2019-2024 4
LIST OF ACRONYMS
ABBREVIATION DEFINITION
ANZECC Australian and New Zealand Environment and Conservation Council
ARMCANZ Agriculture and Resource Management Council of Australia and New Zealand
BGC Project Botany Groundwater Cleanup Project (hydraulic containment and treatment
project)
BIP Botany Industrial Park
BP Bundle piezometer
CFM Chloroform (trichloromethane)
CHC Chlorinated hydrocarbon
CHHRA Consolidated Human Health Risk Assessment
cis-1,2-DCE cis-1,2-dichloroethene
CLC Community Liaison Committee
CoBB City of Botany Bay
CTC Carbon tetrachloride (tetrachloromethane)
CLM Act Contaminated Land Management Act 1997 (NSW)
DNAPL Dense non-aqueous phase liquid
DPIE Department of Planning, Industry and Environment
EDC Ethylene dichloride (1,2-dichloroethane)
EPA Environment Protection Authority
EPL Environment Protection Licence
GAE General Air Emissions
GEEA Groundwater Extraction Exclusion Area
GIR Groundwater Injection and Recovery
GRAMP Groundwater Remediation and Management Plan
GTP Groundwater Treatment Plant
HCB Hexachlorobenzene
HCBD Hexachlorobutadiene
HHRA Human Health Risk Assessment
IMC Independent Monitoring Committee
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ABBREVIATION DEFINITION
mAHD m (above) Australian Height Datum
NCUA Notice of Clean Up Action
NSW New South Wales
OBLC Orica Botany Liaison Committee
PCA Primary Containment Area
POEO Act Protection of the Environment Operations Act 1997 (NSW)
PCE Perchlorethylene (tetrachloroethene)
SESPHU South Eastern Sydney Public Health Unit
SCA Secondary Containment Area
1,1,2,2-TeCA 1,1,2,2-Tetrachloroethane
1,1,2-TCA 1,1,2-Trichloroethane
1,2,4-TCB 1,2,4-Trichlorobenzene
TCE Trichloroethene
URS URS Australia Pty Ltd, an environmental consultant
VC Vinyl chloride (chloroethene)
VMP Voluntary Management Plan
VRA Voluntary Remediation Agreement
GeneralGRAMP 2019-2024 6
1 INTRODUCTION
The NSW Environment Protection Authority (EPA) issued Orica Australia Pty Ltd (Orica) with Notice of Clean
Up Action (NCUA) No. 1030236 on 26 September 2003, under the Protection of the Environment Operations
(POEO) Act 1997. Following consultation with the community and Orica, the then Office of Environment and
Heritage (OEH) determined that the project was best managed by a Voluntary Management Proposal (VMP)
under the Contaminated Land Management Act 1997. The VMP was approved on 5 November 2010
(Approval No. 20101714). The VMP replaced the NCUA as the regulating tool following the NCUA being
revoked on 3 December 2010. The VMP was updated and renewed on 13 August 2015 (Approval No.
20151711) and on 26 March 2020 (Approval No. 2020****).
Orica has prepared this revised Groundwater Remediation and Management Plan (GRAMP) to support the
current VMP.
The objectives of the VMP are as follows:
• To protect human health and the environment via hydraulic containment of the chlorinated
hydrocarbon contaminant plumes and source areas (as outlined in the GRAMP). In the case of
Penrhyn Estuary and Botany Bay, the hydraulic containment works will prevent contaminant
migration to these receptors via groundwater or surface water in order to achieve protection for
slightly to moderately disturbed ecosystems using the Australian and New Zealand Guidelines for
Fresh and Marine Water Quality (ANZG, 2018);
• To monitor the nature and extent of the contamination to identify any potential exposures to the
contamination that require management; and
• To investigate potential technologies to remediate source zones and plumes.
To achieve these objectives Part 3 of the VMP establishes a clear set of undertakings relating to each of the
following components of the project:
• Maintenance and optimisation of hydraulic containment;
• Source area management;
• Contingency measures for the Groundwater Treatment Plant (GTP);
• Community consultation;
• Chemical monitoring programs for groundwater and surface water;
• Assessment of risk to human health and the environment (using the data from the monitoring
programs for groundwater and surface water as well as from additional monitoring programs for air
and other environmental media); and
• Reporting requirements.
1.1 OBJECTIVES
The objectives of this document are as follows:
• Establish a clear set of undertakings relating to each part of the Botany Groundwater Cleanup (BGC)
Project including:
o Maintenance and optimisation of hydraulic containment;
o Chemical and hydraulic monitoring programs for groundwater, surface water, air and other
relevant environmental media;
o Assessment of risk to human health and the environment;
o Source area management;
o Contingencies for the GTP; and
o Community consultation.
• Establish a performance schedule outlining reporting timeframes; and
• Maximise administrative efficiency for both NSW EPA and Orica.
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1.2 DURATION AND REVIEW
Given the particular circumstances of the BGC Project, a review of the regulatory approach (i.e., the VMP)
on a four-yearly basis is considered appropriate, which is consistent with the frequency of the Strategy
Review Workshops (refer to Section 2.5). It is recommended that the review of the VMP occurs after the
Workshop so that any changes to the remediation strategy arising from the Workshop may be incorporated
in the updated VMP. Notwithstanding, adjustments to the scope and content of the activities outlined in this
GRAMP may occur from time to time with the consent of NSW EPA.
1.3 EXCLUSIONS
This document provides descriptions, scopes and schedules for several elements of the BGC Project,
however the VMP does not include the following:
• Operation of the GTP – the operation of the GTP is regulated under the POEO Act via Environment
Protection Licence no. 2148 (EPL 2148).
• Operation of the Groundwater Injection and Recovery (GIR) System – the proposed backup to the
GTP is also regulated under EPL 2148 and by licences under the Water Management Act 2000
(NSW) from WaterNSW, which is part of NSW Department of Planning, Industry and Environment.
2 BACKGROUND
2.1 SUBJECT AREA
The subject area consists of BIP, Southlands and surrounding areas.
Botany Industrial Park and Southlands
BIP is an industrial chemical complex occupying approximately 60 ha located within an industrial and
residential area approximately 12 km south of the Sydney Central Business District (Figure 1). The BIP was
formerly owned by Orica and is now occupied by a number of individual chemical manufacturing companies,
including Orica. The BIP site has a long industrial history (since the early 1940s), and was formerly owned
and operated by Orica’s predecessor company, ICI Australia Pty Ltd. Historical operations at BIP have
resulted in soil and groundwater contamination on and adjacent to the site, including the land known as
Southlands.
Southlands comprises two parcels of land south of the BIP formerly owned by Orica. Southlands is
separated from the BIP by a railway corridor and is split into two blocks by a public road (Nant Street). The
western portion of Southlands (known as Block 2) had been remediated and divested by Orica for light
industrial use. The eastern section (known as Block 1) has also been remediated by Orica and
approximately half has been divested for light industrial use. The remaining half has been retained by Orica
as a flood detention basin, but may also be divested. Orica will retain ownership of corridors of land across
Southlands in order to continue the operation of the GTP’s hydraulic containment network and provide
flexibility for implementing potential future remedial measures.
BIP and surrounding lands are located within a low-lying area at the lower end of the Botany Sands Aquifer,
near Botany Bay and Penrhyn Estuary. The aquifer is comprised of Quaternary aeolian sand deposits, with
thin, discontinuous inter-bedded layers of clay and peaty clay. Significant thicknesses (greater than 5 m in
some locations) of fill are also present, including at Southlands and former sand mines to the north of the
BIP.
The land to the south of BIP was former swampland, which was reclaimed through the installation of surface
drains, including Springvale and Floodvale Drains. These drains, which pass through or are adjacent to BIP
and Southlands and discharge into Penrhyn Estuary, receive flow from surface water runoff, via stormwater
GeneralGRAMP 2019-2024 8
pipes linked to BIP and other properties and public roads. Shallow groundwater also has the potential to
discharge to the drains, including along the unlined sections which pass through Southlands and sections
downstream and (to a lesser extent) upstream.
Groundwater extraction bores linked to the GTP are located along the southwestern boundary of BIP, on
First Street and Second Street, and on the southern Macpherson Street frontage of Southlands. In addition
to the manufacturing operations, there are various shared services within BIP, as well as areas that are
currently unoccupied and/or unused (following decommissioning and/or demolition of former manufacturing
plants).
Surrounding Areas
Land uses surrounding BIP and Southlands include the following:
• Commercial/Industrial: the Botany area is one of Sydney's main industrial hubs. A range of industrial
sites are located within a 1-2 km radius of BIP, including (but not limited to):
o North: Boral Concrete, Visy, Nalco Ecolab, Meadoway Industrial Estate, Haverick Meats,
Hoya Lens Australia, Price & Speed, Nutrisoy, Sell & Parker and Air Liquide Australia Pty
Ltd.
o South: MCS (container terminals), Toll, Solvay Interox, Goodman (warehousing, offices, light
industrial), Orora Limited (recycling, and packaging products), Caltex Terminal, Skippens
Landscape and Building Supplies, mixed light to medium industrial.
o West: Kellogg’s, Allnex Australia Pty Ltd and Australand (warehousing), Southgate Industrial
Park, K&T Metal Fabrications P/L, Californian Smash Repairs, Goodman Portside
Distribution Centre.
• Infrastructure: there are a number of major infrastructure facilities in the vicinity of the BIP, which
include:
o South: the Sydenham–Botany goods railway line, which forms the southwestern boundary of
BIP; and Port Botany, which is located 1.5 km to the south of BIP along the north-eastern
edge of Botany Bay.
o West: Sydney International Airport, 3 km west of BIP.
• Residential: principal residential areas are located to the:
o North: Pagewood and Daceyville.
o South: Banksmeadow.
o West: Botany.
o East: Hillsdale, Matraville and Maroubra.
• Retail: the shopping districts located in the vicinity of the site include:
o North: Westfield Eastgardens.
o East: Bunnings Hardware, Southpoint Shopping Centre.
o South: Shops on Botany Road, Banksmeadow.
• Open space: there are a number of parks, reserves and recreational areas surrounding BIP,
including the following:
o North: Hensley Athletic Field, Mutch Park, Bonnie Doon and Eastlake Golf Courses, David
Philips Playing Fields, and Astrolabe, Jellicoe, Rowland and Nagle Parks.
o South: Botany Golf Course, Sir Joseph Banks Park, Penrhyn Estuary and Botany Bay.
o West: Garnet Jackson Reserve.
o East: Heffron Park.
• Schools: schools located in the vicinity of BIP include:
o North: Pagewood Primary School.
o East: Matraville Primary School.
o West: Banksmeadow Primary School.
2.2 PREVIOUS ENVIRONMENTAL ACTIVITIES
A substantial number of environmental investigations, remediation trials and monitoring events, particularly
for groundwater and surface water, have been conducted by Orica since the mid 1990s. Although
GeneralGRAMP 2019-2024 9
background information is provided where relevant, it is not the purpose of the document to revisit in detail
this long history of environmental activities. Instead, a comprehensive library of documents is provided 0n
the BGC Project website 1.
One document in particular, the Conceptual Site Model (CSM) 2 (Orica, 2017) provides a very detailed
summary of pertinent information derived from the many studies undertaken at BIP and surrounding areas,
including:
• The history of industrial activity and land development at BIP and surrounding properties, including
potentially contaminating activities and land uses;
• The progression and scope of investigation and remediation works undertaken by Orica and its
predecessor ICI Australia Pty Ltd associated with the BGC Project;
• The environmental setting at BIP and surrounding affected properties;
• The inferred sources, nature and extent of contamination, including the various media affected by
the contamination;
• The mechanisms for transport and attenuation of the contaminants, and exposure of identified
receptors to the contamination;
• The potential health and environmental risks which the identified contamination is inferred to pose;
• Effects of current remediation practices, and the results of previous remediation work and trials; and
• Regulatory history of the project.
The CSM will be reviewed and updated every four years.
The reader is referred to these sources for a comprehensive summary of the BGC Project’s history.
2.3 REGULATORY HISTORY
Former Voluntary Investigation and Remediation Agreements
The Orica Botany Groundwater Stage 3 Voluntary Remediation Agreement (VRA) formalised the principal
features of the Five-Year Remediation Plan that ICI Australia (as Orica was then) had formulated following
the release of the ICI Botany Groundwater Stage 2 Survey (Woodward-Clyde, 1996). The VRA (and
subsequent renewals) required Orica to carry out a series of investigative and remediation activities.
Orica successfully implemented most of the tasks under the VRA. The shallow EDC plume hydraulic
containment system – intended to be installed and operated on Southlands – could not be constructed
because the Development Application was rejected by City of Botany Bay (CoBB) Council 3. The pilot-scale
reactive iron barrier on Southlands (under the Five-Year Remediation Plan pre-dating the Stage 3 VRA) was
successfully installed prior to issue of the NCUA.
During 2003 Orica reviewed its overall remediation approach and submitted a proposal to NSW EPA to
revise its work programs. However, following detection of increased concentrations of chlorinated
hydrocarbons (CHCs) in a CoBB production bore in Herford Street, Banksmeadow, NSW EPA decided to
issue the NCUA to Orica in September 2003 to change the remediation focus to a hydraulic containment and
ex situ treatment (‘pump and treat’) solution in order to accelerate progress towards containing the
contaminant plumes.
1
BGC Project website https://www.orica.com/Locations/Asia-Pacific/Australia/Botany/Botany-Transformation-Projects/Groundwater-
Cleanup#.XcC5gOgza70
2
Conceptual Site Model https://www.orica.com/Locations/Asia-Pacific/Australia/Botany/Botany-Transformation-Projects/Groundwater-
Cleanup/publications-reports-and-reviews#csm
3
The City of Botany Bay Council was merged with Rockdale City Council in 2016 to form Bayside Council.
GeneralGRAMP 2019-2024 10
Voluntary Management Proposal and Variation Notices
The VMP was approved on 5 November 2010 (Approval No. 20101714). The VMP replaced the NCUA as
the regulating tool following the NCUA being revoked on 3 December 2010.
A Section 44 Amendment Notice was received by Orica on 23 December 2013 outlining changes to the
VMP. Amendments outlined in the Section 44 Amendment Notice were as follows:
• Implementation of the revised monitoring program;
• Cessation of residential bore monitoring;
• Implementation of the Groundwater Injection and Recovery System; and
• Updated date for the Strategy Review Workshop and associated annual report.
The VMP was then updated in 2015, and a Notice of Approval of Voluntary Management Proposal (no.
20151711) was issued on 13 August 2015. The VMP was largely unchanged from the previous version. The
main changes comprised:
• Updated versions of key reference documents;
• Updated deadlines for key activities and reports;
• Updated text to reflect the renaming of the Community Liaison Committee (CLC) to Orica Botany
Liaison Committee (OBLC);
• Mention that the Groundwater Injection and Recovery (GIR) System trial had been completed;
• Update of some of the community communication tools;
• Removal of reference to collection of residential bore water data; and
• Inclusion of the bioaugmentation field trials.
There were two subsequent amendments to the VMP sought by Orica to reflect updated reference
documents and reporting deadlines. Section 44 Amendment Notices 20164428 and 20174415 were received
by Orica on 15 December 2016 and 19 June 2017, respectively.
In accordance with the four-year review cycle for the VMP, it was further amended in early 2020. Section 44
Amendment Notice no. 2020**** was issued by NSW EPA on *** 2020. These most recent amendments
include:
• Updated reference documents (including this GRAMP);
• Inclusion of the GTP Moving Bed Biofilm Reactor (MBBR) pilot trials;
• Revised frequency of the Strategy Review Workshops and related reporting;
• Updated regulatory status of the GIR System;
• Updated environmental monitoring to support assessments of risk to human health;
• Revised frequency of revisions of the Consolidated Human Health Risk Assessment (CHHRA);
• Removal of reference to the bioaugmentation field trials; and
• Updated reporting and progress deadlines.
2.4 CONTAMINANTS OF CONCERN
This document outlines remediation and environmental management measures for compounds associated
with Orica’s (and ICI Australia’s) historical manufacturing activities at the area now known as the BIP. CHCs
are likely to have leaked or were spilled into the subsurface as dense non-aqueous phase liquid (DNAPL) or
dissolved in water (e.g., in trade waste), along with various waste byproducts, which also contained these
compounds. The main contaminants of concern (including degradation products) pertaining to the BGC
Project are listed below:
Table 2.1 – Contaminants of Concern
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VOLATILE CHLORINATED HYDROCARBONS SEMI-VOLATILE CHLORINATED
HYDROCARBONS
Carbon Tetrachloride (CTC) 1,2-Dichlorobenzene (1,2-DCB)
Methylene Chloride (DCM) 1,3-Dichlorobenzene (1,3-DCB)
Chloroform (CFM) 1,4-Dichlorobenzene (1,4-DCB)
Chloromethane 1,2,4-Trichlorobenzene (1,2,4-TCB)
1,1,1,2-Tetrachloroethane 1,3,5-Trichlorobenzene (1,3,5-TCB)
1,1,1-Trichloroethane 1,2,4,5-Tetrachlorobenzene (1,2,4,5-TeCB)
1,1,2-Trichloroethane (1,1,2-TCA) Pentachlorobenzene (PeCB)
1,1,2,2-Tetrachloroethane (1,1,2,2-TeCA) Hexachlorobenzene (HCB)
1,2-Dichloroethane (EDC) Hexachlorobutadiene (HCBD)
Chloroethane Hexachlorocyclopentadiene
cis-1,2-Dichloroethene (cis-1,2-DCE) Hexachloroethane (HCE)
Tetrachloroethene (PCE) Hexachloropropylene
Trans-1,2-Dichloroethene (trans-1,2-DCE)
Trichloroethene (TCE)
Vinyl Chloride (VC)
Distribution
The distribution of these contaminants of concern is described below:
• The groundwater contaminant plumes extend from BIP in the north to beyond Foreshore Road in the
south as indicated on Figure 2. Historical contamination exists beyond the Secondary Containment
Area (SCA) on Foreshore Road to the aquifer discharge zones at Penrhyn Estuary and Botany Bay.
Historical concentrations in surface waters in the estuary have decreased significantly since Orica
commenced pump and treat activities in late 2004.
• Laterally, the plumes extend almost across the entire width of the downgradient boundary of BIP,
reflecting the wide distribution of the inferred source areas.
• EDC has the highest concentrations in groundwater, with concentrations greater than 1,000 mg/L
present under BIP and off site towards the southwest beyond Botany Road (at depth), where it will
be intercepted by the SCA containment line.
• The contaminants are present throughout the aquifer profile (i.e. in the shallow, intermediate and
deep sections of the aquifer) – excluding the top of the water table where they are not detected at all
– with higher concentrations are typically detected at depth.
• The distribution of the contaminants within the plume areas is dictated by the source areas’
compositions and degradation products. The plumes are likely to overlap to an extent, however, the
main contaminants of concern in the dissolved plumes emanating from the source areas comprise:
o Central and Northern Plumes: EDC, VC, and CTC; and
o Southern Plumes: PCE, CTC and TCE.
2.5 REMEDIATION STRATEGY REVIEW
In December 2007, Orica convened a Botany Groundwater Strategy Review Workshop, involving a number
of international and local environmental experts. The purpose of the Workshop was to conduct a
comprehensive independent review of the current remediation strategy, including a deeper understanding of
DNAPL source area remediation issues and an evaluation of whether there were other remediation
technologies or strategies that might be adopted to address DNAPL, sorbed mass and dissolved mass more
effectively than the current remediation strategy.
The outcomes of the Workshop were presented to the NSW EPA and subsequently the Community Liaison
Committee (CLC, which was replaced by the Orica Botany Liaison Committee (OBLC) in late 2014) in
September 2008. Also presented to the EPA and CLC was a revised strategy for the BGC Project. The
GeneralGRAMP 2019-2024 12
revised strategy included a commitment to conduct further workshops, which was accepted by the EPA and
incorporated into the VMP. The purpose of these Workshops is to conduct a reality check on the remediation
strategy for the GCP.
Under the heading of "Source Area Management" in the current VMP Orica has made the following
commitments:
• "Conduct ongoing review of developments in remediation technologies and techniques for treatment
of Dense Non-Aqueous Phase Liquid (DNAPL), sorbed mass and dissolved-phase CHC
contamination, and their practical applicability to the Botany Groundwater Cleanup Project.
• Convene a Strategy Review Workshop every four years 4 to which it will invite a minimum of three
overseas experts in the field. EPA will be consulted on the selection of the experts prior to the
experts being engaged. The review process will involve consideration by the experts of the annual
reports prepared by Orica (see bullet point below) and worldwide developments in technology in
order to assess whether any current or emerging technologies (including developments in
technology and its applications) are likely (individually or in combination) to provide a practicable
solution and justify the conduct of field trials of those technologies. Appropriate representatives of
the Independent Monitoring Committee (IMC) (as agreed with the Orica Botany Liaison Committee
(OBLC) – refer P4) and EPA will be invited to attend the workshop. The outcome of the Remediation
Strategy Review Workshop will be considered in determining whether field trials of one or more
remediation technologies should be conducted.
• Provide an annual report to EPA that would assess the practical application and effectiveness of
appropriate technologies in relation to the remediation. Every four years 5, this would also include a
detailed summary of the outcomes of the Strategy Review Workshop (refer R3)."
Workshops have been undertaken in 2008, 2011, 2014 and 2017. Reports summarising the discussions and
recommendations from those Workshops have been made available on the BGC Project website 6.
The principal outcomes of the 2017 Workshop are:
• Pump and treat remains the most effective way to manage the groundwater contamination and
achieve the objective of protection of human health and the environment;
• Notwithstanding the fact that a significant amount of contaminant mass has been removed from the
aquifer since 2005, the cleanup will still take a long time;
• There are currently no other cleanup technologies for DNAPL and dissolved phase remediation
available that clearly warrant further investigation;
• More characterisation of the contamination source areas is required to better understand their
architecture, contaminant mass flux, and rate of depletion; and
• The fate and transport of contamination in the aquifer needs to be further investigated. In particular
this requires a deeper understanding of the natural attenuation processes – biological and abiotic –
occurring in the aquifer, and whether they can be used to predict potential remediation endpoints for
the Botany Groundwater Cleanup Project.
The 2017 Workshop also suggested a range of actions. Some of the suggested actions were refinements of
the mass loss investigations work that was already being undertaken and enhancements of the existing
numerical solute transport model:
4
In previous versions of the VMP, Workshops were to be convened every three years.
5
In previous versions of the VMP, the reports were to be provided every three years.
6
Strategy Review Workshop reports https://www.orica.com/Locations/Asia-Pacific/Australia/Botany/Botany-Transformation-
Projects/Groundwater-Cleanup/publications-reports-and-reviews#.Xcizfugza70.
GeneralGRAMP 2019-2024 13
• Consider re-evaluating the 2005 and 2015 contaminant mass estimates with the same size of data
sets;
• When undertaking the soil and groundwater sampling and analysis for the mass loss investigations,
collect more data to increase understanding of attenuation mechanisms and aquifer assimilation
capacity;
• Use a multi-component analysis of existing and new soil concentration data to assess DNAPL
presence;
• Simulate PCE fate and transport in the numerical model to improve understanding of plume
longevity;
• Convert the numerical model to incorporate discrete geological layers;
• Consider linking/modelling geochemical conditions to variable biodegradation rates; and
• Investigate development of numerical model(s) to incorporate matrix diffusion.
The following additional actions were also recommended:
• Update the 6 Step Capture Zone Analysis to incorporate more up-to-date data and modelled capture
targets;
• Using the existing extraction well transects, evaluate the mass flux from the source zones;
• Subject to assessment of practicability, perform clean water field injection tests in certain plumes to
assess the effects of back-diffusion, non-linear/non-equilibrium sorption, and preferential flow on the
number of pore volumes needed to lower the concentrations to specified levels;
• Investigate optimisation of the hydraulic containment system;
• Evaluate a range of amendments to the current remediation approach (such as low-level heating,
mass extraction wells, biosparging, directed groundwater recirculation, and addition of electron
donor, iron sulphide and/or nitrate) to enhance DNAPL dissolution and dissolved phase contaminant
removal.
A number of these recommended actions have been implemented; some have been deferred either to a time
that more practically aligns with the project requirements or are pending the outcomes of other actions.
3 REMEDIATION AND MANAGEMENT
APPROACH
Orica has developed a remediation and management approach for the Botany groundwater contamination.
This strategy is predicated on the significant environmental improvements already being achieved by the
operation of the existing hydraulic containment lines and the GTP and the ongoing management of human
health and ecological health risk. The strategy may also be amended based on the outcomes of subsequent
Strategy Review Workshops. Orica proposes the following remediation and management approach for the
BGC Project:
• Ongoing management of groundwater contamination resulting from Orica’s historic activities to
ensure human health and environmental receptor risks are acceptable. This would be achieved
through ongoing monitoring of the relevant segments of the environment potentially impacted by
contaminated groundwater.
• Continuing optimisation of the operation of the hydraulic containment lines and GTP for protection of
critical human health and environmental exposures and for gradual cleanup of contamination where
containment lines are hydraulically downgradient of source areas. This will be achieved through
increased extraction rates in key areas, and increased reliability of hydraulic containment lines at the
increased extraction rates.
• Operation of the Groundwater Injection and Recovery (GIR) system at BIP if required. GIR is
intended to perform a backup function in the case that the GTP is inoperable for an extended period.
GeneralGRAMP 2019-2024 14
GIR will allow ongoing groundwater extraction at selected SCA wells (or other critical areas) for a
period of up to four months by re-injection of the extracted groundwater on land owned by Orica,
upgradient of the BIP containment line.
• Ongoing review of developments in remediation technologies and techniques for treatment of
DNAPL, sorbed mass and dissolved phase CHC contamination, and their practical applicability to
the BGC Project.
Sections 4 to 8 of this document provide a set of specific actions and commitments around this cleanup
approach.
4 HYDRAULIC CONTAINMENT
The GTP hydraulic containment system was installed as a requirement of the NCUA to prevent migration of
plumes from source areas on BIP to Penrhyn Estuary. It was also envisaged that the mass of contaminants
would be reduced over time.
Approximately 5 to 6.5 ML/day of groundwater is extracted (depending on aquifer response to rainfall) from
three groundwater containment lines:
• Primary Containment Area (PCA) Containment Line: located along the southern (McPherson Street)
boundary of Southlands Blocks 1 and 2;
• Secondary Containment Area (SCA) Containment Line: located in the median strip of Foreshore
Road; and
• BIP Containment Line: located on and parallel to the western boundary of the BIP.
The locations of these containment lines are illustrated in Figure 3.
The proposed remediation and management approach is to maintain hydraulic containment by:
a) Maintaining effective hydraulic containment of contaminants of concerns at the PCA Containment
Line;
b) Maintaining effective hydraulic containment of contaminants of concern at the SCA Containment
Line; and
c) Maintaining effective hydraulic containment of contaminants of concern at the BIP Containment Line
commensurate with the available GTP capacity and operational performance. When available GTP
treatment capacity does not allow full treatment of groundwater extracted at the BIP Containment
Line, priority will be given to areas in the vicinity of Springvale Drain and Second Street, where most
benefit to human health and environmental protection from pumping can be achieved.
4.1 CAPTURE ZONE ANALYSIS
Following a review in 2012 of quarterly reports undertaken since GTP operation began, NSW EPA requested
Orica to undertake a 'Capture Zone Analysis' in accordance with the guidance document A Systematic
Approach for Evaluation of Capture Zones at Pump and Treat Systems (USEPA, 2008). The USEPA (2008)
document nominates the following six steps for systematically performing a capture zone analysis:
• Step 1: Review site data, site conceptual model, and remedy objectives
• Step 2: Define site-specific Target Capture Zone(s)
• Step 3: Interpret water levels
o potentiometric surface maps (horizontal) and water level difference maps (vertical)
o water level pairs (gradient control points)
• Step 4: Perform calculations estimated flow rate calculation
GeneralGRAMP 2019-2024 15
o capture zone width calculation (can include drawdown calculation)
o modelling (analytical or numerical) to simulate water levels, in conjunction with particle
tracking and/or transport modelling
• Step 5: Evaluate concentration trends
• Step 6: Interpret actual capture based on Steps 1-5, compare to Target Capture Zone(s), assess
uncertainties and data gaps
A detailed assessment of hydraulic containment at BIP, PCA and SCA was undertaken by JBS (2012) using
the USEPA (2008) approach. Golder updated this assessment to incorporate more recent hydraulic and
chemical monitoring data in September 2013 (Golder, 2013b).
Recommendations from the JBS (2012) assessment were as follows:
• Biennial sampling of all extraction wells and containment line monitoring wells. These data will be
used to adjust areas of pumping priority (and/or target capture zones);
• Review target capture zones and containment line operation on a three-yearly basis;
• Monitoring of surface water quality on a quarterly basis;
• Monitoring of groundwater levels on a quarterly basis;
• Monitoring of groundwater chemistry on an annual basis;
• Sampling of the combined flow from each containment line on a monthly basis to allow a more
detailed assessment of mass flux removal;
• Develop a program to ensure that water level measurements at SCA and at performance monitoring
wells downgradient of the SCA are reliable. This will require regular assessments of transducer
conversion factors and groundwater salinity at monitoring wells (requiring regular access to SCA
monitoring wells);
• Water level monitoring at BP01/BP117; and
• Connection of the logger at MWB03S to the GTP monitoring system to allow real-time water level
monitoring of shallow groundwater at Springvale Drain.
These recommendations have been implemented.
In 2018 Orica engaged JBS&G to update the Assessment of Hydraulic Containment report (JBS, 2012) to
incorporate more recent monitoring data and updates to regulatory guidelines documents, including the
Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG, 2018). Following
consultation with the NSW EPA, the report (JBS&G, 2019) was finalised in *** 2020.
5 GROUNDWATER AND SURFACE
WATER MONITORING
Groundwater and surface water monitoring (both chemical and hydraulic) is required to measure the
effectiveness of containment activities and for ongoing assessment of potential risks to human health and
the environment.
Scheduled quarterly monitoring events commenced from the inception of the Groundwater Treatment Plant
(GTP) Groundwater and Surface Water Monitoring Program (URS, 2005a) in September 2005. This was
prepared in accordance with the requirements of NCUA No.103236.
The URS 2005 monitoring program was subsequently amended in January 2007 (URS, 2007), October 2009
(URS, 2009), June 2013 (Golder, 2013a) and May 2017 (Golder, 2017). The current GTP monitoring
program (Golder, 2017) is due to be updated in mid-2020.
GeneralGRAMP 2019-2024 16
5.1 SUMMARY OF 2017-2020 MONITORING PROGRAM’S CONTENT
Groundwater Chemical Monitoring
The Golder (2017) monitoring program includes three types of monitoring events for groundwater monitoring:
biannual, annual and biennial (in order of increasing sampling program magnitude).
In summary, the three types of monitoring events consist of the following:
• Biannual
o Undertaken during March of every year (and supplemented by the annual/biennial program
every September).
o Collection of groundwater samples for volatile CHC analysis at BP01/BP117 at Penrhyn
Estuary to complement Penrhyn Estuary pore water monitoring (see below).
o Collection of groundwater samples for volatile CHC analysis at key monitoring locations
located downgradient of the SCA containment line. The purpose of the sampling will be to
supplement the historical dataset to be used in the Annual/Biennial reports to assess CHC
concentration trends downgradient of the SCA containment line.
• Annual
o Undertaken during September of every year (and supplemented by the biennial program
every second September).
o Collection of samples from the uppermost shallow groundwater monitoring locations to allow
comparison of volatile CHC concentrations against the concentrations considered in the
revised Consolidated Human Health Risk Assessment (CHHRA) (EnRiskS, 2018) with
respect to the potential for vapour arising from shallow groundwater.
• Biennial
o Undertaken during September of every second year (alternate to annual monitoring).
o Collection of samples from the uppermost shallow groundwater monitoring locations to allow
comparison of volatile CHC concentrations against the concentrations considered in the
CHHRA (EnRiskS, 2018) with respect to the potential for vapour arising from shallow
groundwater.
o Collection of samples from shallow, intermediate and deep groundwater on a extended
network of monitoring locations to assess changes in the volatile CHC distribution and
changes in plume migration throughout the Groundwater Extraction Exclusion Area (GEEA).
o Analysis of selected samples for semi-volatile CHCs.
Penryhn Estuary Pore Water Monitoring
The pore water monitoring program (Golder, 2017) includes biannual monitoring at low tide of the pore water
at the eastern transect of piezeometers (BP42 and BP43) and western transect of piezometers (BP64 and
BP65). Monitoring of the pore water on a biannual basis facilitates comparison to the understanding of
contaminant attenuation and mixing within the intertidal subsurface zone described in the conceptual site
model (Orica, 2017), and supplements surface water sampling at Penrhyn Estuary.
Monitoring of the piezometers at high tide is not considered necessary as historical pore water
concentrations are typically higher at low tide (and thus enable conservative assessment of conditions in the
estuary). In relation to monitoring of pore water at Penrhyn Estuary the following is noted:
• Public access to Penrhyn Estuary is now restricted due to the Port Botany Expansion. The risk
exposure pathway for members of the public that was considered in previous versions of the CHHRA
is no longer relevant.
• There is no unacceptable human health risk associated with ingestion of fish caught outside Penrhyn
Estuary (that may be derived from the estuary).
GeneralGRAMP 2019-2024 17
Surface Water Monitoring
Under the surface water monitoring program (Golder, 2017) surface water samples are collected from
Springvale Drain, Floodvale Drain and Penrhyn Estuary on a biannual basis and are analysed for volatile
CHCs. The biennial monitoring program includes analysis for semi-volatile CHCs.
The monitoring program (Golder, 2017) has been limited to sampling at low tide only as historical monitoring
data indicate that volatile CHC concentrations (when present) are consistently higher at low tide than at high
tide and as a result provide a conservative assessment of water quality in the estuary.
Hydraulic Monitoring
The 2017-2020 hydraulic monitoring program (Golder, 2017) consists of:
• Biannual collection of hydraulic monitoring data (including continuously logged data) to assess
hydraulic containment at the SCA, PCA and BIP Containment Lines.
• Annual and biennial hydraulic monitoring (as part of the biannual events) data to be used for
discussion of long-term monitoring data and changes to the groundwater flow regime within the
broader area.
5.2 SUMMARY OF 2020-2024 MONITORING PROGRAM’S CONTENT
Groundwater Chemical Monitoring
The 2020-2024 groundwater monitoring program will be very similar to the 2017-2020 monitoring program
(Golder, 2017). The principal differences are italicised herein. It will also include three types of monitoring
events for groundwater monitoring: biannual, annual and biennial (in order of increasing sampling program
magnitude).
In summary, the three types of monitoring events consist of the following:
• Biannual
o Undertaken during February of every year (and supplemented by the annual/biennial
program every August).
o Collection of groundwater samples for volatile CHC analysis at BP01/BP117 at Penrhyn
Estuary to complement Penrhyn Estuary pore water monitoring (see below).
o Collection of groundwater samples for volatile CHC analysis at key monitoring locations
located downgradient of the SCA containment line. The purpose of the sampling will be to
supplement the historical dataset to be used in the Annual/Biennial reports to assess CHC
concentration trends downgradient of the SCA containment line.
• Annual
o Undertaken during August of every year (and supplemented by the biennial program every
second August).
o Collection of samples from the uppermost shallow groundwater monitoring locations to allow
comparison of volatile CHC concentrations against the concentrations considered in the
revised Consolidated Human Health Risk Assessment (CHHRA) (EnRiskS, 2018) with
respect to the potential for vapour arising from shallow groundwater.
• Biennial
o Undertaken during August of every second year (alternate to annual monitoring).
o Collection of samples from the uppermost shallow groundwater monitoring locations to allow
comparison of volatile CHC concentrations against the concentrations considered in the
CHHRA (EnRiskS, 2018) with respect to the potential for vapour arising from shallow
groundwater.
o Collection of samples from shallow, intermediate and deep groundwater on a extended
network of monitoring locations to assess changes in the volatile CHC distribution and
changes in plume migration throughout the Groundwater Extraction Exclusion Area (GEEA).
o Analysis of selected samples for semi-volatile CHCs.
GeneralGRAMP 2019-2024 18
Penryhn Estuary Pore Water Monitoring
The 2020-2024 pore water monitoring program will be very similar to the 2017-2020 monitoring program
(Golder, 2017). The principal differences are italicised herein. It will also include biannual monitoring at low
tide of the pore water at the eastern transect of piezeometers (BP42 and BP43 – or equivalent if they are
replaced) and western transect of piezometers (BP64 and BP65 – or equivalent if they are replaced).
Monitoring of the pore water on a biannual basis facilitates comparison to the understanding of contaminant
attenuation and mixing within the intertidal subsurface zone described in the conceptual site model (Orica,
2017), and supplements surface water sampling at Penrhyn Estuary.
Monitoring of the piezometers at high tide is not considered necessary as historical pore water
concentrations are typically higher at low tide (and thus enable conservative assessment of conditions in the
estuary). In relation to monitoring of pore water at Penrhyn Estuary the following is noted:
• Public access to Penrhyn Estuary is now restricted due to the Port Botany Expansion. The risk
exposure pathway for members of the public that was considered in previous versions of the CHHRA
is no longer relevant.
• There is no unacceptable human health risk associated with ingestion of fish caught outside Penrhyn
Estuary (that may be derived from the estuary).
Surface Water Monitoring
Under the 2020-2024 surface water monitoring program, which will be essentially identical to the 2017-2020
monitoring program (Golder, 2017), surface water samples will be collected from Springvale Drain, Floodvale
Drain and Penrhyn Estuary on a biannual basis and are analysed for volatile CHCs. The biennial monitoring
program includes analysis for semi-volatile CHCs.
The monitoring program will be limited to sampling at low tide only as historical monitoring data indicate that
volatile CHC concentrations (when present) are consistently higher at low tide than at high tide and as a
result provide a conservative assessment of water quality in the estuary.
Hydraulic Monitoring
The 2020-2024 hydraulic monitoring program will be essentially identical to the 2017-2020 monitoring
program (Golder, 2017). It will consist of:
• Biannual collection of hydraulic monitoring data (including continuously logged data) to assess
hydraulic containment at the SCA, PCA and BIP Containment Lines.
• Annual and biennial hydraulic monitoring (as part of the biannual events) data to be used for
discussion of long-term monitoring data and changes to the groundwater flow regime within the
broader area.
5.3 REPORTING SCHEDULE
The schedule of reporting chemical and hydraulic monitoring results reflects the three different chemical
monitoring programs for groundwater, pore water and surface water described above.
Biannual Reporting
Quarterly reports present chemical data associated with surface water, pore water and groundwater
downgradient of the SCA containment line, as well as focusing on hydraulic containment at SCA, PCA and
BIP containment lines. Interpretation of chemical data is limited to significant changes in quality that are
identified during biannual monitoring rounds. Discussion and/or explanation of the changes are included in
the report. The monitoring reports include the following:
• Presentation of surface water monitoring, groundwater (downgradient SCA wells and BP01/BP117)
and Penrhyn Estuary pore water, including comparison of the data against historical results.
• Details on variations from the monitoring program, and the reasons for the variations.
GeneralGRAMP 2019-2024 19
• Comparison of results against environmental and human health receptors considered in the CHHRA
(EnRiskS, 2018).
The hydraulic component of the biannual report includes the following:
• Presentation of hydrographs showing groundwater elevations at GTP wells and surrounding
monitoring wells.
• Presentation of interpretive groundwater flow maps showing groundwater elevation contours and
flow lines in the areas immediately surrounding the containment lines.
• Assessment of hydraulic containment at the SCA, PCA and BIP containment lines by comparison
against the assumptions and hydraulic containment data assessed by JBS (2012).
• Assessment of water levels at Southlands and comment on potential for discharge of shallow
groundwater to Springvale Drain.
Annual Reporting
The chemical monitoring component of the annual report is interpretive and focuses on the assessment of
groundwater and surface water quality with respect to environmental and human health receptors and plume
migration in areas where relatively rapid migration has previously been observed. The assessment includes
considerations of:
• Concentrations of CHCs against long-term trends and changes in contaminant distribution (including
parametric tests).
• Concentrations of CHCs against assumptions and results considered in the CHHRA (EnRiskS,
2018).
Chemical data are presented in tabular form, and are compared against historical data using the existing
parametric trend analysis. To assist in the assessment of plume dynamics and distribution, figures are
presented for selected CHCs.
In addition to the biannual scope, the annual hydraulic monitoring component of the report assesses long-
term data and the groundwater flow regime within the broader area of the lower GEEA. The report includes
long-term water level plots for key monitoring locations.
Biennial Reporting
The biennial reports, in addition to the chemical and hydraulic reporting discussed below, review the
suitability of the GTP monitoring program in terms of the appropriateness of data being collected and
potential data gaps.
The chemical monitoring component of the biennial report is interpretive and focuses on major changes to
plume composition and distribution throughout the GEEA. The biennial report provides assessment of plume
behaviour and distribution, as well as assessment of groundwater and surface water quality with respect to
environmental and human health receptors.
The hydraulic component of the biennial report is the same as the annual report. A review of target capture
zones (in accordance with JBS (2012) and Golder (2013b)) and containment line operation is conducted.
Monitoring of the GTP system extraction and monitoring wells may be reported separately by Orica.
Table 5.1 – Monitoring Scope and Reporting Schedule – Groundwater and Surface Water Monitoring
Program
SAMPLING SCHEDULE REPORTING SUBMISSION MONITORING EVENT
DATE STATUS
GeneralGRAMP 2019-2024 20
September 2017 30 November 2017 Biennial
March 2018 31 May 2018 Biannual
September 2018 30 November 2018 Annual
March 2019 31 May 2019 Biannual
September 2019 30 November 2019 Biennial
March 2020 31 May 2020 Biannual
September 2020 30 November 2020 Annual
* Note – Monitoring plan may be revised following the 2020 Strategy Review Workshop based on Workshop outcomes.
Copies of the reports are provided to the following parties:
• NSW EPA
• NSW Department of Planning, Industry and Environment (DPIE) – Water;
• NSW Department of Health and the South East Sydney Public Health Unit (SESPHU);
• Bayside Council;
• Members of the Orica Botany Liaison Committee (OBLC); and
• Public libraries in the Botany area.
Electronic copies of the report are also be posted on the website 7.
5.4 MONITORING PROGRAM REVIEW
The VMP indicates that the purpose of groundwater and surface water monitoring is to “measure the
effectiveness of the hydraulic containment activities, to identify changes in the magnitude and extent of the
contamination and to allow for the ongoing assessment of risks to human health and the environment”. It is
acknowledged in the VMP (P5) that the frequency and the scope of the monitoring program will be reviewed
periodically.
The next review of the monitoring program is scheduled to occur in 2020, however, the monitoring program
is intended to be flexible and may be adjusted between reviews as conditions require, and with agreement
from NSW EPA.
6 ASSESSMENT OF RISK TO HUMAN
HEALTH
6.1 CONSOLIDATED HUMAN HEALTH RISK ASSESSMENT
The 2017 CHHRA (EnRiskS, 2018) was prepared by Environmental Risk Sciences (EnRiskS) in accordance
with the requirements of the VMP. It is essentially an update of the 2005 CHHRA (URS, 2005b) and 2010
CHHRA (EnRiskS, 2010). The 2017 CHHRA remains an assessment of human health risk issues in areas off
7
Groundwater and surface water monitoring reports https://www.orica.com/Locations/Australia--Pacific-and-Indonesia/Australia/Botany-
Remediation-Projects/Projects/Groundwater-Cleanup/Publications--Reports---Reviews/progress-reports#.XcjVWOgza70
GeneralGRAMP 2019-2024 21
the BIP associated with exposures that may occur as a result of contamination that may be derived from the
BIP. The assessment has incorporated additional data and information that include the following:
• Additional data (soil, groundwater, surface water and air) collected to June 2017;
• Revisions to national guidance as provided by enHealth (enHealth 2012) and National Environment
Protection Council (NEPC 1999 amended 2013);
• Changes to access and use of Penrhyn Estuary as a result of the Port Expansion works. These
works have resulted in the removal of all public access to Penrhyn Estuary (inner and outer estuary
areas) and the relocation of the boat ramp to an area further north, and out of the estuary;
• Remediation and additional assessments that have been conducted in relation to the presence
and/or management of contaminants derived from the BIP, which include:
o Former ChlorAlkali Plant (FCAP);
o Southlands;
o Car Park Waste Encapsulation (CPWE); and
o Biota;
• Updated Conceptual Site Model (CSM) for the Orica Botany Site (Orica 2017);
• Assessment of the potential presence of contamination in areas located off the BIP in work
• commissioned by the NSW EPA;
• Updates to the evaluation and quantification of toxicity for some of the chemicals assessed in the
2010 CHHRA (EnRiskS 2010); and
• Where available and relevant, updates relevant to the quantification of exposure.
The 2017 CHHRA was reviewed by NSW EPA and NSW Health.
In accordance with the commitments in the VMP, the 2017 CHHRA is due to be updated in July 2022 to take
into account more recent consolidated monitoring data and changes to relevant exposure scenarios,
toxicological data and risk calculation methods.
6.2 MONITORING
Previously, the groundwater and surface water monitoring programs had been supplemented with a 15-
monthly general air emissions (GAE) monitoring program to provide data for consideration in the CHHRAs.
The last GAE monitoring report was issued in October 2019. For many years the GAE monitoring reports
returned very low flux emission, ambient air and soil gas results. Following advice from the risk assessor,
EnRiskS and consultation with NSW EPA and the OBLC, the GAE monitoring program has been replaced
with a reactive air emissions monitoring program. Under the reactive air emissions monitoring program, flux
emission, ambient air and/or soil gas samples will be collected only if certain groundwater concentration and
level conditions are triggered, which are discussed in the 2017 CHHRA (EnRiskS, 2018):
• Exceedance of trigger values for specific CHCs in shallow groundwater, and in surface water within
Springvale Drain:
Adopted Screening Level – Adopted Screening Level –
Groundwater (mg/L) Springvale Drain (mg/L)
Analyte South of
Western Nant Street
Main Plumes McPherson
Margin Tank Farm
Street
Carbon Tetrachloride 0.0007 0.003 0.7
Chloroform 0.25 0.25 1.4
Methylene Chloride 0.004
1,1,2,2-
0.36
Tetrachloroethane
GeneralGRAMP 2019-2024 22
Adopted Screening Level – Adopted Screening Level –
Groundwater (mg/L) Springvale Drain (mg/L)
Analyte South of
Western Nant Street
Main Plumes McPherson
Margin Tank Farm
Street
1,1,2-
0.41 0.41
Trichloroethane
1,1-Dichloroethane 3.8 3.8
1,2-Dichloroethane 0.003 0.003 3.5
Chloroethane 21
Tetrachloroethene 0.05 0.05 3
Trichloroethene 0.02, 0.00281 0.02, 0.00281 0.8
1,1-Dichloroethene 0.03 0.03
cis-1,2-
0.06 0.06 1.5
Dichloroethene
trans-1,2-
0.06 0.06
Dichloroethene
Vinyl Chloride 0.0003 0.0003 0.8
Hexachlorobenzene 0.001
Hexachlorobutadiene 0.0007 0.0007
Note 1: Two screening levels were identified for TCE in the CHHRA (EnRiskS, 2018): 0.02 mg/L from World
Health Organisation Drinking Water Guidelines (WHO, 2011) and 0.0028 mg/L from US Regional
Screening Level for Tap Water (USEPA, 2016).
• Exceedance of a groundwater level of 2.3 m AHD in monitoring well MWB03S adjacent to Springvale
Drain and the McPherson Street crossing for at least three months.
6.3 REPORTING
The reporting regime for assessment of risk to human health is provided below:
• Updates on changes to risks outlined in the CHHRA from changes to concentrations in groundwater
and surface waters will be provided in the biannual groundwater and surface water reports described
as per Section 5.
• At the end of February every year (other than the year of a revision of the CHHRA), should data
collected in the previous 12 months determine that risk profiles have changed, an annual Addendum
will be issued summarising the changes to the risk profiles outlined in the CHHRA. If the risk profiles
have not been altered significantly no addendum will be issued.
• Every four years, the entire CHHRA will be revised to take into account more recent consolidated
monitoring data and changes to relevant exposure scenarios, toxicological data and risk calculation
methods.
6.4 SPRINGVALE DRAIN
The NSW EPA raised concerns in 2011 regarding the reporting of hydrograph data from groundwater wells
adjacent to Springvale Drain and use of these data as triggers for the collection of additional data for the
assessment of vapour risks to workers adjacent to the drain. Based on a review by EnRiskS (2012), it was
considered appropriate that the process by which groundwater elevations and surface water data are
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