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GROUNDWATER
MONITORING & MANAGEMENT PLAN
FORMER HILLS INDUSTRIES SITE SOUTH ROAD
EDWARDSTOWN
SOUTH AUSTRALIA
Prepared for:
Novion Property Group
Date: February 2016 Reference No: 3698
Plan Version: 3698/GMMP/02
Prepared by: Greencap
(formerly AEC Environmental Pty Ltd)
AEC ENVI R ONM E NT AL 12 Greenhill Rd Wayville SA 5034 P O Box 582, Unley SA 5061 Ph: 08 8299 9955 Fax: 08 8299 9954 Email: aec@aecaust.com.au Web: www.aecaust.com.au
www.aecaust.com.au
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TABLE OF CONTENTS
1.0 INTRODUCTION .............................................................................................. 1
1.1 Management Areas ................................................................................................... 2
2.0 BACKGROUND AND PREVIOUS INVESTIGATONS..................................... 5
2.1 Previous Investigations and Site Remediation Works ............................................... 5
2.2 Background Information............................................................................................. 6
2.3 Groundwater Beneficial Use Assessment (BUA) .................................................... 13
3.0 GROUNDWATER MONITORING & MANAGEMENT PLAN ......................... 14
3.1 GMMP Objectives & Structure................................................................................. 14
3.2 Responsible Parties ................................................................................................. 15
3.3 Groundwater Monitoring Program ........................................................................... 16
3.4 Groundwater Monitoring Well Network ...................................................... 19
3.5 Groundwater Analytical Program ............................................................................. 23
3.6 Data Quality Objectives ........................................................................................... 26
3.7 Groundwater Sampling Methodology ...................................................................... 29
3.8 Reporting Process & Structure ................................................................................ 30
4.0 COMPLIANCE TARGETS & TRIGGER LEVELS.......................................... 32
4.1 Background.............................................................................................................. 32
4.2 Trigger Levels .......................................................................................................... 34
4.3 Application of Trigger Levels ................................................................................... 38
5.0 CONTINGENCY MEASURES ........................................................................ 40
6.0 REVIEW OF GMMP AND CESSATION OF MONITORING .......................... 41
6.1 Review of GMMP ..................................................................................................... 41
6.2 Cessation of Monitoring ........................................................................................... 41
7.0 REFERENCES ............................................................................................... 43
APPENDICES
Appendix A Monitoring Well Logs and Construction Details
Appendix B EPP Schedule 2 Water Quality Criteria œ Compliance Targets
Appendix C Groundwater Sampling Results
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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AEC Document Control
Report Title & AEC Job Ref:-
Groundwater Monitoring & Management Plan œ
Former Hills Industries Site, Edwardstown,
South Australia
(AEC Ref: 3698/GMMP/02)
Filename:-
3698 Groundwater Monitoring and Management
Plan Finalv2
Written:
Alex Sereda
Principal Hydrogeologist
Approved:
Nick Waniarcha
Environmental Manager œ SA
Rev No Status Date Author(s) Reviewer(s)
Draft Draft 17/05/2013 DB/AS NW
Draftv2 Draft 06/03/2015 DB/AS/JL NW/JL
Draftv3 Draft 16/06/2015 DB/AS/JL NW/JL
Draftv4 Draft 10/08/2015 DB/AS/JL NW/JL
1 Final 30/09/2015 DB/AS/JL NW
2 Final 01/02/2016 DB/AS/JL NW
Rev No Copies Recipient
2 1 x electronic ERM / Novion / URS
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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1.0 INTRODUCTION
AEC Environmental Pty Ltd (AEC) has been engaged by Novion Property Group (formerly
Colonial First State Global Management (CFSGAM)) to prepare a Groundwater Monitoring &
Management Plan (GMMP) for the former Hills Holdings Ltd (Hills) manufacturing site located
on South Road, Edwardstown (the site). URS has reviewed and contributed to the
development of the GMMP on behalf of Hills. The former Hills Industries site location is shown
on Figure 1.
FORMER HILLS INDUSTIRES SITE
Figure 1 œ Site location (source: UBD)
During the environmental soil and groundwater investigations conducted at the former Hills
Industries site significant soil and groundwater issues (particularly relating to chlorinated
solvent impacts) were identified. The solvent impacts appear to have migrated off-site under
the residential area located to the west.
In accordance with SA environmental legislation, the SA EPA was notified of the issue and
since 2010, the SA EPA has been part of a stakeholder group to manage the impact. The SA
EPA undertook a number of public consultations and a letter drop to notify local residents and
stakeholders of the impacts (refer http://www.epa.sa.gov.au).
As a direct result of the impact, SA EPA accredited Auditor, Mr Warren Pump of ERM Pty Ltd
(ERM), were engaged to provide independent opinion on the assessment and remediation
works conducted for the former Hills Industries site, associated off-site impacts and
subsequent measures required to manage the on-site and off-site contamination.
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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http://www.epa.sa.gov.au
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1.1 Management Areas
The contractual arrangement between Novion (formerly CFSGAM) and Hills for the sale of the
land at the former Hills Industries site places the responsibility for assessment and remediation
of contamination upon Novion except that Hills retains liability for the assessment and
remediation of off-site contamination.
AEC was engaged by Novion for the on-site environmental works, assessment of impacts and
remediation. URS Australia Pty Ltd (URS) was appointed by Hills to complete the
environmental works and to provide on-going advice relating to the off-site impacts.
1.1.1 On-site
The former Hills Industries site comprises an irregular shaped block of approximately 7.8
hectares described by 20 Certificates of Title containing 29 individual allotments. All titles are
legally described for the area named Edwardstown, Hundred of Adelaide. The site lies in an
area currently zoned Industry / Commerce within the City of Marion.
The site is to be re-zoned for mixed use, with part of the site to be redeveloped for ongoing
commercial / industrial use within the footprint of the proposed extension of the Castle Plaza
shopping Centre. For reporting purposes and to align with the proposed development plan,
the on-site area was divided into three assessment areas, each of which is under statutory
audit.
Audit Area 1 œ Comprises 7 Certificates of Title with an area of approximately 4.9 hectares, including Allotment 288 in which the vast majority of past operations were
undertaken (Audited by Mr Warren Pump).
Audit Area 2 œ Comprises 12 Certificates of Title with an area of approximately 1.78 hectares (Audited by Mr Paul Fridell).
Audit Area 3 œ Comprises 9 allotments in two areas (Mixed Use Area 1 and Mixed Use Area 2) with an area of 1.184 hectares (Audited by Mr Paul Fridell).
Legal descriptions for the Audit Area 1 allotments are presented in Table 1. The Allotment
layout is presented in Figure 2.
Table 1 œ Summary of former Hills Industries site legal descriptions
Certificate of Title
(Volume / Folio) Lot Number(s)
Street
Number Street Name Plan
Audit Area 1
5409 / 849 288 944 - 956 South Rd Filed Plan 10796
5411 / 384 1 958 South Rd Deposited Plan 27678
5649 / 591 4 5 - 7 Ackland St Deposited Plan 4772
5656 / 612 5 & 6 5 - 7 Ackland St Deposited Plan 4772
5804 / 381 290 958 South Rd Filed Plan 10796
5804 / 382 291 1 Ackland St Filed Plan 10796
5494 / 212 292 944 - 956 South Rd Filed Plan 10796
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Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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Figure 2 œ On-site location (source: Property Location Browser)
1.1.2 Off-site
The off-site component of the GMMP relates to the off-site land located to the west and north
west of the former Hills Industries site (see Figure 2). The extent of the off-site assessment
works was described as to the west of the former Hills Industries site extending to:
Marion Road to the west; Melville Street and Maxwell Avenue to the north; and Nelson Street, Edwardstown Oval and Oval Avenue to the south.
The extent of the off-site groundwater monitoring well network is presented in Figure 3.
1.1.3 GMMP Area
This GMMP pertains to the on-site (Audit Area 1 œ AA1) and off-site areas to the west of the
site. The off-site area boundary is defined by the delineated extent of the identified
groundwater contamination plume(s) outlined by the locations of the off-site delineation
groundwater wells (see Figures 3 and 4). The locations of the existing on-site and off-site
groundwater monitoring wells, as of October 2014 are shown on Figure 3.
The on-site and off-site areas are collectively referred to as the ”GMMP Area‘ for the purpose
of this GMMP.
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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Figure 3 œ Groundwater Investigation Monitoring Well Network
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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2.0 BACKGROUND AND PREVIOUS INVESTIGATONS
2.1 Previous Investigations and Site Remediation Works
Results of the previous investigations are outlined in the following reports:
o Phase 1 Environmental Site Assessment œ Hills Industries Site, Edwardstown.
Prepared by Parsons Brinkerhoff (Report reference: 2121207A-001/RK/kmg).
November 2006.
o Limited Environmental Site Investigation. Hills Industries Factory 944-958 South Rd,
Edwardstown, South Australia. Prepared by Environmental & Earth Sciences NSW
(Report reference: 107053). June 2007.
o Addendum to Environmental Earth Sciences NSW Report Number 107053 œ Quality
Assurance and Quality Control Document. Prepared by Environmental Earth
Sciences NSW (Report Reference 111109). December 2011.
o VI & Risk Assessment Advice œ Vapour Issues Edwardstown. Prepared by
Environmental Risk Sciences (Report reference: A/10/L101-B). January 2010.
o VI & Risk Assessment Advice œ Vapour Issues Edwardstown. Prepared by Environmental Risk Sciences (Report reference: A/10/L201-C). December 2010.
o Off-site Groundwater Monitoring, Edwardstown, January 2014. Prepared by URS (Report Reference: 42657630/R009/01). February 2014.
o 944-956 South Road, Edwardstown. Off-site Groundwater Investigations, Screening
Risk Assessment and Solute Transport Modelling. Prepared by URS (Report
Reference: 42657630/R008/3). May 2014.
o 944-956 South Road, Edwardstown. Off-site Groundwater Monitoring. Prepared by
URS (Report Reference: 42657630/R010/0f). May 2014.
o 944-956 South Road, Edwardstown. Detailed Risk Assessment for Off-site Groundwater Contamination. Prepared by URS (Report Reference:
42657630/R011/2 DRAFT). August 2014.
o Off-site Groundwater Monitoring, Edwardstown, October 2014, Prepared by URS (Report Reference: 42657630/R013-1). December 2014.
o On-Site Vapour Risk Assessment œ 944-958 South Road, Edwardstown. Prepared by Environmental Risk Sciences (Report reference AEC/12/EVR001-E). August
2015.
o Environmental Site Assessment & Screening Risk Assessment œ ”Audit Area 1‘, Portion of Former Hills Industries Site, Corner of South Road & Ackland Street,
Edwardstown, South Australia. Prepared by AEC Environmental (Report Reference:
3698/AA1/01). September 2015.
o Detailed Risk Assessment œ ”Audit Area 1‘, Portion of Former Hills Industries Site, Corner of South Road & Ackland Street, Edwardstown, South Australia. Prepared by
AEC Environmental (Report Reference: 3698/AA1/01). September 2015.
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The on-site remediation works have been presented in the following reports:
o Remediation of PCE Impacted Soils œ Source Removal Works Report œ Allotment 288, Hills Industries Site, South Road, Edwardstown, South Australia. Prepared by
AEC Environmental (Report Reference: 3698/R02). February 2012.
o Environmental Site Assessment & Screening Risk Assessment œ ”Audit Area 1‘, Portion of Former Hills Industries Site, Corner of South Road & Ackland Street,
Edwardstown, South Australia. Prepared by AEC Environmental (Report Reference:
3698/AA1/01). September 2015. Herein referred to as AA1 ESA/SRA.
o Detailed Risk Assessment œ ”Audit Area 1‘, Portion of Former Hills Industries Site, Corner of South Road & Ackland Street, Edwardstown, South Australia. Prepared by
AEC Environmental (Report Reference: 3698/AA1/DRA/01). September 2015.
Herein referred to as AA1 DRA.
o Remediation Options Assessment œ ”Audit Area 1‘, Portion of Former Hills Industries
Site, Corner of South Road & Ackland Street, Edwardstown, South Australia.
Prepared by AEC Environmental (Report Reference: 3698/AA1/ROA/01).
September 2015. Herein referred to as AA1 ROA.
2.2 Background Information
2.2.1 GMMP Area Settings
The GMMP Area (including on-site Audit Area 1 and the off-site area) lies approximately six
kilometres south to south-west of the Adelaide CBD.
At present (following demolition works undertaken between 2009 and 2013, Audit Area 1 is
vacant unpaved land with scattered vegetation. The rest of the GMMP Area (off-site)
comprises (primarily) residential allotments as shown on Figure 3.
The GMMP Area is an essentially level area with a gentle slope from the east toward the west.
2.2.2 Geological Settings
The GMMP Area is situated in the Adelaide Plains in a landform area known as the Lower
Alluvial Plain.
The general geological sequence at the GMMP Area comprises:-
o Quaternary Age sediments of fluvial and marine origin of the order of 50 metres thickness. The dominant formation is Hindmarsh Clay, which is predominantly clay,
but has lenses of gravels, silts and sands. The Hindmarsh Clay is covered by clayey
material of the Keswick Clay and Pooraka formations.
o Tertiary sediments of mainly marine origin up to 200 metres thickness are
represented by limestones, sands and calcareous sandstones of the Port Willunga,
Chinaman Gully, Blanche Point and other formations.
o Precambrian Age basement rock below approximately 200-250 metres depth.
Groundwater Monitoring & Management Plan (February 2016)
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Quaternary age material comprises the following:-
o Pooraka Formation œ approximately 3 to 5 metres thick;
o The Pooraka Formation typically consists of sandy clay and clayey to sandy silt, with interbeds and layers of clay, sand and occasional gravel. Layers
rich in carbonate silt and segregations occur within the Pooraka Formation;
o Transitional Gley Clay and / or Keswick Clay and / or Quaternary Alluvium œ approximately 5 metres thick;
o Keswick Clay consists primarily of clay but may also contain bands of silty or gritty clay (quartz sand inclusions) and includes transitional Gley Clay œ —gley“
is a colour name applied to clay layers that have been subject to poor or
impeded drainage conditions and have greyish to greenish colours and
mottle patterns;
o Quaternary Alluvium - is found throughout the Hindmarsh Clay, Pooraka
Formation and the Keswick Clay. The deposits follow present and past
drainage lines that emerge from the EdenœBurnside and Para Fault
Escarpments. The material is predominantly sandy in texture may also
contains abundant silt, clay, gravel and pebbles and
o Hindmarsh Clay œ greater than 10 metres thick comprising predominantly clay with some sand and silt content.
2.2.3 Hydrological Features
No subsurface stormwater drainage features are known to be present on the AA1 site (on-
site). The area outside AA1 includes stormwater drainage network which collects stormwater
runoff from the streets and residential allotments and discharges into the nearby drains, creeks
and river systems.
The nearest watercourse or surface water body is the Sturt River which lies approximately
three kilometres to the west of the former Hills Industries site, part of which flows within a
concrete channel. Gerges (2006) defined the Sturt River as an ephemeral watercourse
indicating that the river only flows during periods of rainfall and is dry during periods when
there is no rain. This also indicates that the base flow of the river is not influenced or
maintained by groundwater discharge into the river.
The Gulf of St Vincent (marine) is located approximately 6 km to the west of the former Hills
Industries site.
2.2.4 Hydrogeological Settings
The Conceptual Site Model presented in the Detailed Risk Assessment reports (AA1 DRA and
the off-site DRA), referenced in Section 2.1 identified that there is likely to be six aquifers
located beneath the GMMP Area as follows:
o Three aquifers within the Quaternary age sediments (Q1, Q2 and Q3); and
o Three aquifers within the Tertiary age sediments (T1, T2 and T3).
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Q1 is the uppermost aquifer identified within the Pooraka Formation represented by sandy
clay and clayey to sandy silt, with interbeds and layers of clay, sand and occasional gravels.
Q1 is underlain by a confining bed represented by stiff clays of the Keswick Clay formation
and the upper portion of the Hindmarsh Clay formation also represented by stiff clays.
The Q2 and Q3 aquifers are located within the sandy, gravelly silts and sand layers within the
Hindmarsh Clay formation. The aquifers are separated by stiff clay layers within the
Hindmarsh Clay.
The T1 aquifer is located within the limestones of the Port Willunga formation. The T1 aquifer
is separated from the Q3 aquifer by a layer of clay which forms the base of the Hindmarsh
Clay formation. The T1 aquifer is underlain by a dark grey clay layer which separates the T1
and T2 aquifers.
The T2 and T3 aquifers are likely to be intersected at the depths greater than 120m below the
GMMP Area ground level and it is unlikely that these deep Tertiary aquifers will have any
significant influence on the groundwater regimes of the Quaternary aquifers.
The potential influences from the contaminated portion of the Q1 aquifer on the groundwater
quality of deeper Quaternary and Tertiary aquifers was assessed using groundwater level
hydrographs plotted for wells installed in the Q1, Q2, Q3 and T1 aquifers (refer the DRA report
for detail).
The relationship between the groundwater levels of the Q1 to Q3 and T1 aquifers was
interpreted as follows:
o The Q2 aquifer exhibits the highest groundwater levels and some natural upward and downward leakage may occur into Q1 and Q3 aquifers respectively;
o Downward leakage from the Q3 aquifer may occur into the underlying T1 aquifer;
o No leakage from the Q1 aquifer into the Q2, Q3 or T1 aquifers is likely to occur naturally; and
o If any pumping from the T1 aquifer occurs this is unlikely to influence groundwater levels in the Q1 aquifer as it is separated from the T1 aquifer by the Q2 and Q3
aquifers and the confining beds separating the Q1/Q2, Q2/Q3 and Q3/T1 aquifers.
The information summarised above indicates that under natural conditions the groundwater
contamination identified within the Q1 aquifer is unlikely to impact on the water quality of
deeper aquifers and therefore the GMMP primarily addresses groundwater monitoring
requirements for the Q1 aquifer only. As two existing on-site groundwater monitoring wells
installed within the Q2 aquifer remain on-site they have been included in the GMMP to verify
the above statements.
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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2.2.5 On-site/Off-site Groundwater Contamination
The extents of the identified groundwater contamination plumes within the Q1 aquifer are
presented in Figure 4.
The groundwater contamination investigations and risk assessments are summarised below
in regards to the GMMP requirements and documentation referenced in Section 2.1.
Environmental Site Assessment & Screening Risk Assessment (AA1 ESA/SRA)
o Identified CHCs sources were investigated and remediation works were undertaken
which included bulk PCE impacted soil excavation above the groundwater interface.
Report 944-956 South Road, Edwardstown Off-site Groundwater Investigations,
Screening Risk Assessment and Solute Transport Modelling (Off-site)
o The solute transport modelling undertaken for the chlorinated solvent contaminated groundwater plume within the on-site/off-site area used the groundwater monitoring
results collected prior and post site remediation works.
o The modelling results suggest that the PCE, TCE and DCE plumes are likely to be in approximate steady state, such that the ongoing flux of PCE dissolving and desorbing
from the assumed secondary source area within the former Hills‘ site is balanced by
ongoing natural attenuation processes (incorporating advection, dispersion,
volatilisation and possible degradation).
Detailed Risk Assessment (AA1 DRA)
o The solvent impacts are not considered to pose an unacceptable risk for the proposed
redevelopment of the site.
o The Solute Transport Modelling report prepared by URS identified that the chlorinated solvent plume has reached a steady state condition, i.e. the plume is likely to have
reached its maximum distance and concentrations, no further expansion of the plume
is expected. To confirm continued plume stability, regular monitoring is required.
o Recommendations of the DRA included the preparation of a Remediation Options
Assessment (ROA), a Groundwater Monitoring & Management Plan (GMMP) and a
Construction Environmental Management Plan (CEMP).
Remediation Options Assessment (AA1 ROA)
o The assessment, undertaken in accordance with the SA EPA‘s ”Guidelines for the Assessment and Remediation of Groundwater Contamination‘ (February 2009)
identified that the use of Monitored Natural Attenuation (MNA) of chlorinated solvents
and other groundwater impacts is a feasible and appropriate remediation measure
given the modelled stability of the plume, level of risk assessed and lack of future
beneficial use at the site;
o As recommended in the ROA, MNA should be implemented under the guidance of a GMMP.
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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Report 944-956 South Road, Edwardstown Detailed Risk Assessment for Off-site
Groundwater Contamination (Off-site DRA)
o The off-site DRA concluded that given that the source is inferred to have been present for at least 40 years, the plume is considered to be in a steady state, oxidising
conditions have been observed throughout the plume, and no major sources of
hydrocarbon releases have been identified within the plume area, it is unlikely that
concentrations of PCE daughter products within the plume will increase significantly
over time.
o The off-site DRA also concluded the following:
o No unacceptable health risks have been identified for the following receptors:
Off-site residents who do not use the groundwater. This exposure scenario is likely to apply to a large majority, if not all, of the residents
within the inferred plume area. This conclusion remains irrespective
of whether or not the residents have a regularly occupied basement.
Off-site residents (with or without basements) who use the shallow groundwater for irrigation of gardens and/or recreational purposes
only.
Off-site commercial workers. Off-site intrusive workers. Recreational park users. Visitors to off-site properties.
o Unacceptable health risks may exist for the following hypothetical receptors:
Off-site residents (if any) who use the shallow groundwater for showering/bathing as well as for irrigation and recreation.
Unacceptable health risks would only exist where the groundwater
contains concentrations of PCE and TCE above approximately 0.50
mg/L and 0.03 mg/L respectively. Based on the most recent testing,
this may apply to a zone extending up to 150m west from Railway
Terrace, within the area bounded by Stanton Street to the west,
Fuller Street to the north and Johnson Street to the south.
Off-site residents (if any) who use the shallow groundwater as a primary source of potable drinking water. Unacceptable health risks
would only exist where contaminant concentrations exceed drinking
water guideline levels. Monitoring results suggest this may apply in
a zone extending up to 1km west of the former Hills‘ site.
o Based on the groundwater modelling results, the bulk of the chlorinated ethenes plume appears to be in an approximate steady state, which implies
that future risk levels will be the same as current risk levels until such time
when the residual source is depleted, causing concentrations and health risks
to decline towards background levels.
Groundwater Monitoring & Management Plan (February 2016)
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o The off-site DRA recommended that the groundwater plume should be monitored
periodically to check whether concentrations of PCE, TCE, DCE, vinyl chloride and
nitrate remain consistent with previous results. A Groundwater Monitoring and
Management Plan should be developed to define the required monitoring as well as
trigger levels and contingency actions that may need to be implemented if needed,
depending on monitoring results.
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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Figure 4 œ Groundwater Contamination Plumes (URS and AEC October 2014 data)
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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2.3 Groundwater Beneficial Use Assessment (BUA)
The South Australian Environment Protection (Water Quality) Policy 2003 and the SA EPA
guideline Site Contamination Guidelines for the Assessment and Remediation of Groundwater
Contamination (February 2009) identified the following protected environmental values /
beneficial uses of underground waters in South Australia: -
o Freshwater aquatic ecosystems
o Marine aquatic ecosystems
o Potable
o Primary and secondary contact recreation
o Aesthetics
o Irrigation
o Livestock
o Aquaculture
o Industrial
The guideline also requires an assessment of non-use scenarios for groundwater which
include:
o Human health œ exposure to volatile chemicals through vapour flux where there is no
contact with impacted groundwater
o Building and structures œ protection from chemicals presented in groundwater which may degrade building footings etc.
The BUAs for the on-site groundwaters identified that recreational and/or industrial beneficial
groundwater use is possible from the deep Tertiary (T1) aquifer. No realistic (current and
future) on-site beneficial uses for the Quaternary (Q1, Q2 and Q3) aquifers were identified.
For non-use scenarios, groundwater may impact on future on-site building footings and
structures if constructed deep enough to intersect the Q1 aquifer.
The BUA for the off-site groundwater identified that the potential beneficial uses of shallow
groundwater include potable use (although unlikely to apply in practice), recreational and
aesthetic use, irrigation of domestic gardens (including watering of fruit and vegetables) and
eventual discharge to the marine environment (approximately 4 km to the west).
It should be noted that during discussion held between SA EPA, Hills, Novion, Marion Council,
ERM (Auditors), URS and AEC (12 December 2014), the Auditor indicated that preliminary
audit recommendations would include "Control the use of groundwater with blanket ban in
defined area (reduced area to that of the current EPA Investigation Area) unless testing
conducted prior to use". For the purpose of this GMMP it is assumed that the defined area
will extend to encompass the area in which on-site and off-site groundwater contamination has
been identified (see Figure 4) at levels above the most sensitive water guideline values
(potable use).
Groundwater Monitoring & Management Plan (February 2016)
Former Hills Industries Site, South Road, Edwardstown (Version 3698/GMMP/02) (Ref:- 3698)
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3.0 GROUNDWATER MONITORING & MANAGEMENT PLAN
3.1 GMMP Objectives & Structure
This Groundwater Monitoring & Management Plan (GMMP) has been prepared in general
accordance with the South Australian Environment Protection Authority guidelines —Regulatory
Monitoring and Testing - Groundwater Sampling“ (SA EPA, June 2007) and “Site
Contamination Guidelines for the Assessment and Remediation of Groundwater
Contamination” (SA EPA, February 2009).
It is recommended that this GMMP is incorporated into the Site Management Plan1, which is
to remain in use post-construction of the site (it is noted that a Construction Environmental
Management Plan2 exists for AA1).
Other SA EPA Guidelines considered are as follows:
o Guidelines; Regulatory Monitoring and Testing, Monitoring Plan Requirements, December 2006; and
o Guidelines; Regulatory Monitoring and Testing, Reporting Requirements, August
2007.
The Victorian EPA publication 840.1, February 2014 —The Clean Up and Management of
Polluted Groundwater“ has also been considered in the preparation of this GMMP.
This GMMP aims to accomplish the following objectives:
o Regular monitoring of the identified impacted groundwater plume to verify that the plume is stable.
o Identification of potential changes to the assessed levels of risk to human health
and environment from the identified contamination plume via the monitoring of
contamination concentrations, groundwater depth and comparison to established
trigger levels that may indicate a shift in the level of risk. Measures of change
include contaminant concentration levels, plume extent trends, changes in
concentrations of PCE daughter products (TCE, DCE and VC), groundwater head
shift and change in flow direction.
o Establishing mechanisms and management measures or remedial actions which could be implemented if the plume extent and/or the level of risk shows an
increasing trend.
1 Site Management Plan, ”Audit Area 1‘ Portion of Former Hills Industries Site, Corner of South Road & Ackland Street, Edwardstown, South Australia, January 2016. Prepared by Greencap (Reference: J101276_03/01).
2 Construction Environmental Management Plan, ”Audit Area 1‘ Portion of Former Hills Industries Site, Corner of South Road & Ackland Street, Edwardstown, South Australia, September 2015. Prepared by Greencap (Reference: 3698/AA1/CEMP/01).
Groundwater Monitoring & Management Plan (February 2016)
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This GMMP comprises the following components:
o The groundwater monitoring schedule and analytical program;
o Provisional compliance targets and trigger levels;
o Provisional contingency measures established for the situations if the trigger levels
are exceeded; and
o Periodic review of the practicability of GMMP to address the required objectives.
3.2 Responsible Parties
The Responsible Parties for the implementation of this GMMP are as follows:
o Novion Property Group (formerly Colonial First State Global Asset Management)
are responsible for facilitating on-site groundwater monitoring;
o Hills Limited are responsible for facilitating off-site groundwater monitoring;
o Environmental consulting firms are responsible for the on-site and off-site
groundwater monitoring programs respectively;
o South Australian Environment Protection Authority (SA EPA) is responsible for review of the GMMP results and GMMP adequacy to control risk level in the GMMP
Area (on-site and off-site). The SA EPA may delegate the review process to an
appointed Site Contamination Auditor; and
o Marion City Council in consultation with SA EPA is responsible for public
awareness of groundwater contamination status in the GMMP Area to ensure that
the public health and the environment adequately protected.
The relevant Responsible Parties should ensure that:
o all other relevant parties are made aware of their responsibilities, such as maintenance workers and other persons conducting excavations on or off site;
o work procedures are developed to address site specific management issues and OH&S requirements relating to this GMMP and any relevant Environmental
Management Plans; and
o groundwater monitoring and reporting activities are followed as per the schedules outlined in this GMMP.
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3.3 Groundwater Monitoring Program
The groundwater monitoring program is outlined in Table 2.
Table 2 œ Groundwater Monitoring Program
Activity / Item Details
1. Monitoring Groundwater monitoring events (GMEs) for the wells Requirements
located within the AA1 site (on-site) shall be conducted
by an experienced environmental consultant.
GMEs for the wells located off-site shall be conducted by
an experienced environmental consultant.
Groundwater monitoring will commence in October 2015.
2. Standing Water Level Groundwater level gauging will be conducted biannually Gauging
(every six months) at the end of dry (April) and wet
(October) seasons. All wells included in Table 3 shall be
gauged biannually irrespective of the groundwater
sampling protocol.
The measured levels shall be recorded and reported
relative to AHD.
The gauging data will be used to assess and verify the
inferred groundwater flow direction and will also be used
to evaluate changes in depth to groundwater to identify
potential risks to human health from increased elevations
of groundwater and potential vapour flux.
3. Monitoring Well
Groups
The wells included in the GMMP are split in two groups.
One group of wells will initially be sampled twice per year.
This group has been selected based on quarterly rounds
undertaken previously by AEC and URS. The wells in this
group are generally located along the centreline of the
solvent contaminated plume and they are:
o On-site œ MWD, MWE, MWF, MWG, MWH, MWH_Q2, MWJ, MWK, MWAL, MWBK and
MWBL;
o Off-site œ MWS, MWAC, MWAD, MWAH, MWAS, MWAV, MWBE, MWBF, MWBG and
MWBI.
The other group of wells will be sampled annually to
monitor the groundwater quality outside the centreline of
the plume. This group includes the rest of the wells shown
in Table 3.
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Activity / Item Details
4. Monitoring Duration
and Frequency
The duration of the groundwater monitoring under the
guidance of this GMMP is not specified and will depend
on the results of the monitoring and subsequent reviews
(see Item 10).
The gauging of all on-site and off-site wells included in
Table 3 should be undertaken within 2 days to avoid
potential changes in water levels over a longer period of
time.
The monitoring of groundwater quality (groundwater
monitoring event, GME) shall be undertaken on a six-
monthly basis as follows:
o April
o October
On-site and off-site monitoring events are to be co-
ordinated to be undertaken concurrently where possible.
5. Groundwater Groundwater monitoring wells shall be sampled in Sampling accordance with the requirements of the SA EPA
Methodology
Guidelines —Regulatory monitoring and testing -
Groundwater Sampling” (June 2007) or as updated.
The recommended sampling method is —low-flow“ or
—micropurge“ as detailed in Section 3.7.
6. Quality Assurance / QA/QC samples shall be collected and analysed in Quality Control
accordance with the general requirements of the SA EPA
Guidelines —Regulatory monitoring and testing -
Groundwater Sampling“ (June 2007) and —Site
Contamination Guidelines for the Assessment and
Remediation of Groundwater Contamination“ (February
2009) as well as the National Environment Protection
(Assessment of Site Contamination) Measure 1999 (as
amended 2013) or as updated.
As minimum QA/QC samples shall include intra and inter
laboratory duplicates, field and trip blanks and rinsates.
Monitoring equipment is to be decontaminated between
the sampling of each monitoring well.
7. Groundwater Samples from monitoring wells shall be collected and Analytical Program analysed at a NATA accredited testing laboratory as
specified in Tables 4 and 5 (Section 3.5). The facility is
to be NATA accredited to conduct the specified analyses
using NATA accredited analytical methods.
8. Reporting
Requirements
Reporting shall be conducted in accordance with the general requirements of the SA EPA Guidelines
—Regulatory monitoring and testing - Groundwater
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Activity / Item Details
Sampling” (June 2007) and “Guidelines; Regulatory
Monitoring and Testing, Reporting Requirements, August
2007” or as updated.
It is important to note that if during any GME the
concentrations of the chemicals of interest show a
significant increase particularly in wells where the
concentrations have been reported below laboratory
reporting limits, an updated notification of groundwater
contamination must be completed and forwarded to the
SA EPA as required under the Environment Protection
Act 1993.
Reports are to be completed as follows:
o Factual report (on-site) œ to be completed after every
GME.
o Factual report (off-site) œ to be completed after every
GME.
o Interpretative report (on-site) œ to be completed
annually after every second GME.
o Interpretative report (off-site) œ to be completed
annually after every second GME.
o 3-yearly report (on-site) œ to be completed every 3
years.
o 3-yearly report (off-site) œ to be completed every 3
years.
Monitoring results for each on-site and off-site monitoring
event are to be reported separately.
On-site and off-site data consolidation (i.e. GMMP Area
data review) is to be undertaken by the concurrent review
of the two reports by the EPA and/or the appointed EPA-
accredited Auditor.
Consolidation of the reports may not be required
immediately following GMEs as the types and levels of
risks identified for on-site (source area) and off-site
(residential area) differ (refer on-site/off-site DRAs).
The structures of reports are outlined in Section 3.8.
9. Reporting Frequency
and Report
Submission Protocol
Factual reports results of each GME will be reported by
appointed consulting firms for on-site and off-site
separately and submitted to the SA EPA/Auditor
biannually, i.e. in May and December (refer Section 3.8).
Upon completion of biannual and annual GMEs, annual
reports (one on-site and one off-site) outlining the results
of the two groundwater monitoring events shall be
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Activity / Item Details
prepared by appointed environmental consulting firms
addressing the trends in concentrations of chemicals of
concern (listed in the analytical program above). Details
of the reporting are included in Section 3.8.
10. Reviews The GMMP is to be reviewed every three years. The first GMMP review is scheduled to be undertaken after the
October 2017 GME.
The review schedule is subject to SA EPA/Auditor approval. The review will assess whether any
amendments to the GMMP are required (e.g. increasing
or reducing the set of analytes and/or number of wells) or
monitoring may be discontinued (see Section 6.2).
The GMMP review should be undertaken by appointed environmental consulting firms in consultation with the SA
EPA and/or an Auditor. Details of review process/protocol
is included in Section 6.0.
3.4 Groundwater Monitoring Well Network
3.4.1 Monitoring Well Network
The selection of groundwater monitoring wells for the ongoing monitoring was based on the
following criteria:
o The wells are located in and around the areas where the key chemicals (i.e. chlorinated solvents PCE, TCE, DCE and VC) are present;
o Q2 wells are also included in the GMMP monitoring well network to provide
information on potential downward connectivity between Q1 and Q2;
o The well coverage should be sufficient to monitor the key areas of groundwater impacts; and
o The wells should be located at areas where the potential for well damage is minimal.
The groundwater monitoring wells selected for ongoing monitoring together with the well
coordinates, construction details and aquifer in which they are installed are included in Table
3. The locations of the monitoring wells are presented in Figure 5. Well logs are attached in
Appendix A.
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Table 3 œ GMMP Well Details
Well ID Easting
(MGA94)
Northing
(MGA94)
Reference
Elevation
TOC*
(mAHD**)
Screened
Interval (m)
Well
Completion
ON-SITE WELLS (AA1)
Q1 Wells
MWC 278356 6126722 27.781 3.8 - 6.8 Standpipe
MWD‘ 278383 6126821 27.645 4.0 - 7.0 Standpipe
MWE 278428 6126836 27.906 3.8 - 6.8 Standpipe MWF‘ 278329 6126836 27.35 4.0 - 7.0 Standpipe MWG‘ 278272 6126832 26.750 3.5 - 6.5 Standpipe
MWH 278245 6126817 26.268 4.2 - 7.2 Standpipe
MWJ‘ 278289 6126800 27.040 3.6 - 6.6 Standpipe MWK 278351 6126825 27.800 3.0 - 6.0 Standpipe
MWM 278210 6126736 25.945 3.6 œ 6.6 Gatic
MWAL 278362 6126797 27.96 4.0 - 7.0 Standpipe
MWAM 278491 6126835 28.719 4.0 - 7.0 Standpipe
MWAZ 278498 6126701 28.722 4.5 - 7.5 Standpipe
MWBK 278333 6126815 27.143 3.6 - 6.6 Standpipe MWBL 278290 6126821 27.830 3.9 - 6.9 Standpipe
Q2 Wells
MWC_Q2 278352 6126723 27.772 11.0 - 20.0 Standpipe
MWH_Q2 278246 6126821 26.968 11.0 - 20.0 Standpipe
OFF-SITE WELLS
Q1 Wells
MWR 278217 6126850 25.571 3.0 œ 6.0 Gatic
MWS 278205 6126824 25.473 3.0 - 6.0 Gatic
MWV 278168 6126893 25.258 2.5 œ 5.0 Gatic
MWY 278039 6126824 24.244 2.5 - 5.5 Gatic
MWAB 278180 6126763 25.278 2.5 - 5.5 Gatic
MWAC 278166 6216730 25.273 2.5 - 5.5 Gatic
MWAD 278140 6126683 25.356 3.0 - 6.0 Gatic
MWAF 278045 6126745 24.455 2.5 - 5.5 Gatic
MWAH 277890 6126954 23.045 2.5 - 5.5 Gatic
MWAP 277893 6126685 22.818 2.0 - 5.0 Gatic
MWAQ 277709 6126759 21.441 2.0 - 5.0 Gatic
MWAR 277648 6126913 20.823 2.0 - 5.0 Gatic
MWAS 277649 6127023 20.840 2.5 - 5.5 Gatic
MWAT 277822 6127109 22.262 2.0 - 5.0 Gatic
MWAU 277415 6127187 18.926 2.0 - 5.0 Gatic
MWAV 277418 6127003 18.990 2.5 - 5.5 Gatic
MWAW 277430 6126895 19.082 2.5 œ 5.0 Gatic
MWBB 277537 6126610 20.240 1.5 - 6.0 Gatic
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Well ID Easting
(MGA94)
Northing
(MGA94)
Reference
Elevation
TOC*
(mAHD**)
Screened
Interval (m)
Well
Completion
MWBC 278011 6126493 23.478 1.5 - 6.0 Gatic
MWBE 277265 6126868 18.056 1.5 - 6.0 Gatic
MWBF 277195 6126976 17.796 1.5 - 6.0 Gatic
MWBG 278052 6126871 24.363 1.5 - 6.0 Gatic
MWBI 277245 6127106 17.729 1.5 - 6.0 Gatic
MWBJ 278091 6126984 24.576 1.5 - 6.0 Gatic
Notes:
*TOC œ top of casing;
**AHD = Australian Height Datum
All wells to be gauged biannually (every 6 months)
Highlighted wells to be sampled biannually (every 6 months)
All other wells to be sampled annually
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Figure 5 œ GMMP Monitoring Wells
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3.4.2 Well Maintenance
The integrity of all monitoring wells should be maintained for the duration of the GMMP.
If during a groundwater monitoring event (GME) any monitoring wells are found to be damaged
the following protocol should be applied:
o Any damaged monitoring wells should be repaired prior to the next scheduled
GME;
o If any of the monitoring wells included in this GMMP are damaged beyond repair, the damaged monitoring wells should be decommissioned as per requirements
outlined in the “Minimum Construction Requirements for Water Bores in Australia
(2003)“ and replacement monitoring wells should be installed;
o The location and necessity of the replacement well installation shall be undertaken
in consultation with the SA EPA/Auditor. If found necessary the replacement wells
shall be constructed as per requirements presented in SA EPA Guideline œ
Regulatory Monitoring and Testing, Groundwater Sampling, June 2007; and
o All replacement monitoring wells should have a reference point for water level gauging clearly marked and professionally surveyed.
3.5 Groundwater Analytical Program
3.5.1 Field Parameters
Field parameters are to be measured prior to sampling as detailed in the SA EPA Guideline œ
Regulatory Monitoring and Testing, Groundwater Sampling, June 2007. Parameters are to
include temperature, dissolved oxygen (DO), pH, conductivity and redox potential. Further
guidance is provided in Section 3.7.
3.5.2 Analytical Suites
Samples collected from the monitoring wells within the network are subject to varying analyses
as driven by the contaminants of concern identified in the on-site and off-site DRAs and
parameters that are indicators for the occurrence of the natural attenuation (as noted in the
AA1 ROA). The analytical program for the groundwater wells to be monitored biannually is
summarised in Table 4 and for groundwater wells to be monitored annually is included in Table
5.
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Table 4 œ Groundwater Analytical Program (April)
Well ID TDS Field
pH
CHC
Suite1 NO3, NH4 Nickel
Chromium
VI
Major
Cations/
Anions2
TRH3 BTEX4
ON-SITE WELLS (AA1)
Q1 Wells
MWD X X X X X X
MWE X X X X X X X
MWF X X X X X X
MWG X X X X X X X
MWH X X X X X X X
MWJ X X X X X X X X
MWK X X X X X X
MWAL X X X X X X X
MWBK X X X X X X X
MWBL X X X X X X X
Q2 Wells
MWH_Q2 X X X X X
OFF-SITE WELLS
Q1 Wells
MWS X X X X
MWAC X X X X
MWAD X X X X
MWAH X X X X
MWAS X X X X
MWAV X X X X
MWBE X X X X
MWBF X X X X
MWBG X X X X
MWBI X X X X
Notes: 1 CHC suite includes PCE, TCE, DCEs and VC at low level detection limits. 2 Cations/Anions œ chloride, sulphate, carbonite, bicarbonate, sodium calcium, magnesium, potassium. 3 TRH œ total recoverable hydrocarbons (C6 to C40 as per NEPM). 4 BTEX œ benzene, toluene, ethylbenzene and xylenes.
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Table 5 œ Groundwater Analytical Program (October)
Well ID TDS Field pH
CHC Suite1
NO3, NH4 Metals2
Major Cations / Anions3
TRH4 BTEX5
ON-SITE WELLS (AA1)
Q1 Wells
MWC X X X X X
MWD X X X X X X
MWE X X X X X X X
MWF X X X X X X
MWG X X X X X X X
MWH X X X X X X X
MWJ X X X X X X X
MWK X X X X X X X
MWM X X X X X X X
MWAL X X X X X X X
MWAM X X X X X
MWAZ X X X X X
MWBK X X X X X X X
MWBL X X X X X X X
Q2 Wells
MWC_Q2 X X X X X
MWH_Q2 X X X X X X
OFF-SITE WELLS
Q1 Wells
MWR X X X X X
MWS X X X X X
MWV X X X X X
MWY X X X X X
MWAB X X X X X
MWAC X X X X X
MWAD X X X X X
MWAF X X X X X
MWAH X X X X X
MWAP X X X X X
MWAQ X X X X X
MWAR X X X X X
MWAS X X X X X
MWAT X X X X X
MWAU X X X X X
MWAV X X X X X
MWAW X X X X X
MWBB X X X X X
MWBC X X X X X
MWBE X X X X X
MWBF X X X X X
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Well ID TDS Field pH
CHC Suite1
NO3, NH4 Metals2
Major Cations / Anions3
TRH4 BTEX5
MWBG X X X X X
MWBI X X X X X
MWBJ X X X X X
Notes: 1 CHC suite includes PCE, TCE, DCEs and VC at low level detection limits. 2 Metals œ Arsenic, Barium, Beryllium, Cadmium, Chromium (total and hexavalent), Cobalt, Copper, Iron, Lead,
Manganese, Mercury, Nickel, Vanadium, Zinc (field filtered). 3 Cations/Anions œ chloride, sulphate, carbonate, bicarbonate, sodium calcium, magnesium, potassium. 4 TRH œ total recoverable hydrocarbons. 4 BTEX œ benzene, toluene, ethylbenzene and xylenes.
3.6 Data Quality Objectives
The following sections are designed to provide an overview of the data objectives and data
quality objectives (DQO) for the groundwater monitoring program. The project specific data
quality objectives (DQOs) are outlined in Table 6.
Table 6 œ Sampling Design Data Quality Objectives
DQO
Step
Stage Discussion and Requirements
1 State the Problem Groundwater underlying the site area has been contaminated as
a result of historical on-site activities. The investigation conducted
to date determined that the site contamination of groundwater
exists, and the extents of the identified contaminated groundwater
plumes have been delineated.
2 Identify the Decision The site contamination of groundwater is present and delineated.
The ROA report identified that the Monitoring of Natural
Attenuation (MNA) of the contamination plumes is considered an
appropriate management / remediation strategy which requires
the development of a Groundwater Monitoring Program to confirm
that the plume remains in a steady state, NA within the plume is
occurring at the rates predicted by the solute transport modelling
and the risks to the human health and environment are at the
levels assessed by DRAs.
3 Identify the Inputs to
the Decision
A network of groundwater monitoring wells has been established
across the on-site (AA1) and off-site areas, and groundwater
samples have been collected and analysed. Results have been
compared to adopted assessment criteria. The assessment
criteria are based on the appropriate protected environmental
value, determined via a beneficial use assessment as per SA EPA
guidance.
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DQO
Step
Stage Discussion and Requirements
4 Define the Boundaries
of the Study
The boundaries of the study have been defined by the SA EPA
and shown on Figure 5.
5 Develop a Decision
Rule
The results indicated site contamination of groundwater in relation
to the chlorinated solvents, metals, hydrocarbons and nitrate
because:-
o The chemical substances identified have come to be
present as a result of an activity; and
o The results are above background concentrations and
the water quality criteria for the appropriate protected
environmental value.
6 Specify Tolerable
Limits on Decision
Errors
The possible decision errors arising out of the program could be:-
1. Concluding site contamination of groundwater exists
when it actually does not (i.e. a false positive result); or
2. Concluding site contamination of groundwater does not
exist when it actually does (i.e. a false negative result).
3. Concluding risks associated with groundwater
contamination are acceptable while using erroneous
and/or false negative results.
Whilst three types of decision errors would be undesirable, the
second and third type errors would be the least desirable
outcome, and therefore the design of the program must to be
conservative to account for this. It will not be possible to design
the program to limit the chances of these errors to a defined
numerical value, as such the program design is highly
judgemental and will rely on input from personnel with appropriate
hydrogeological expertise.
7 Optimise the Design
for Obtaining Data
The program design is based on establishing a monitoring well
network that constructed to allow for:
o consideration of background groundwater quality;
o determination of groundwater levels and hydraulic
gradient;
o assessment of groundwater quality across the GMMP
Area (AA1 and off-site);
o targeting and delineation of the impacted areas
identified; and
o adequate assessment of risks to potential groundwater
uses including human health and the environment.
Specific data quality objectives for the laboratory and field components of the GMMP including
sampling and reporting protocols (refer Sections 3.7 and 3.8 respectively) are outlined in the
Table 7.
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Table 7 œ Field & Laboratory Work Data Quality Objectives
Component of
Works
QA/QC Aspects Data Quality Objectives
Fieldwork Quality Sampling procedures Sampling to be conducted in accordance with
documented standard procedures based on
industry best practice.
Field records (logs, purge records, sampling
records) to be documented and provided in all
factual reports.
Sample handling, storage,
transport
Samples to be stored and transported on ice in
chilled portable containers.
Sample integrity to be verified by Chain of
Custody documentation.
Field equipment Calibration and maintenance records to be
provided in all factual reports.
Equipment to be decontaminated between
monitoring of each well as per industry standards.
Laboratory quality -
general
Overall quality and
reliability.
NATA accredited laboratories to be used for all
analyses. The laboratories should also hold
NATA accreditation for all analytical methods.
Laboratory Quality
œ internal
measures
Accuracy Measured by laboratory spike and surrogate
recovery samples. Results should generally be
within 70% - 130% recovery.
Precision Measured by laboratory duplicate sample
analysis. Results should be within 30% relative
percentage difference.
Overall Completeness Minimum 95% completeness (measured by total
number of analyses within acceptable limits).
Laboratory Quality
œ external
measures
Precision Measured by field duplicate sample analysis.
Results should be within 50% relative percentage
difference.
Cross contamination and
introduced contamination
during sampling and
transport
Measured by trip blank analyses. Results should
be below lab reporting limits.
Decontamination Measured by equipment blank analysis. Results
should be below lab reporting limits.
Overall Completeness Minimum 95% completeness (measured by total
number of analyses within acceptable limits).
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3.7 Groundwater Sampling Methodology
Groundwater sampling methodology adopted for this GMMP is consistent with the
groundwater sampling methodology used to collect previous groundwater samples from the
on-site and off-site groundwater monitoring wells.
The GMMP groundwater sampling methodology shall follow the requirements of the SA EPA
guideline —Regulatory monitoring and testing - Groundwater Sampling” (June 2007) and shall
be undertaken as detailed below:
o Standing water level (SWL) should be measured before purging and sampling. The
SWL should be measured with a purpose-built tape or meter, and from a
permanently marked and surveyed reference point at the top of the groundwater
well casing. Measurements should also be taken to check for any light non-
aqueous phase liquid (LNAPL) present in the wells.
o Stagnant water in the well casing can be different, both physically and chemically, from the aquifer water. Hence the well must first be purged before a representative
sample can be obtained. Well purging introduces fresh groundwater into the well
that is representative of the aquifer (or geological unit).
o Groundwater purging from a well shall be undertaken using the —low-flow“ purging
technique.
o During groundwater purging the following parameters should be monitored depth to groundwater level, pH, temperature, electrical conductivity, oxidation reduction
potential and dissolved oxygen. The groundwater quality parameters should be
monitored using an appropriately calibrated water quality meter.
o Groundwater purging records should be documented as per requirements of the
SA EPA Guideline.
o Groundwater samples can be collected when three consecutive measurements of water quality parameters are stabilised within the ranges defined in the SA EPA
guideline. Samples to be analysed for metals should be filtered using 0.45たm filters in the field prior to filling appropriate sampling containers. Collected groundwater
samples shall be placed in chilled containers provided by an analytical laboratory.
o Quality Assurance and Quality Control (QA/QC) for groundwater sampling shall follow the requirements of the SA EPA Guidelines and the requirements of the
National Environment Protection (Assessment of Site Contamination) Measure
1999 (as amended 2013) and should include collection of field duplicates (intra-
laboratory) at the rate of 10%, field triplicates (inter-laboratory) at the rate of 20%,
transport blanks at the rate of one blank per sampling batch, container blanks at
the rate of one blank per a transport container (potable cooler) and rinsate samples
at the rate of one rinsate per a day of sampling.
o All equipment used in the sampling procedure which either enters the well bore or
holds the groundwater sample should be decontaminated before and after each
groundwater sample is collected and should include the following as a minimum:
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1. Rinse and scrub all reusable sampling equipment in a solution of tap
water mixed with phosphate free detergent (e.g. Decon90) using the
mix proportion listed on the Decon90 container.
2. Rinse devices and measuring tape in tap water to remove any excess
detergent.
3. Rinse device and measuring tape in laboratory issued deionised/demineralised water.
o Groundwater samples should be stored on ice bricks in a portable cooler immediately following collection and delivered under similar conditions to the
analytical laboratory with accompanying chain of custody (COC) documentation.
o Analytical laboratories selected for the groundwater sample analyses shall be accredited by the National Association of Testing Authorities (NATA) for the
analyses performed.
3.8 Reporting Process & Structure
The reporting schedule for this GMMP is presented in the following sections. All reports shall
be submitted electronically in a PDF format.
3.8.1 Annual and Biannual GME Factual Reports
Factual reports are to be prepared following the completion of each GME. Reporting
requirements are as follows:
o Separate reports for on-site and off-site GMEs shall include general information on
site conditions, groundwater sampling methodology, summary of field parameters
and analytical results, QA/QC, data comparison with GMMP trigger levels and a
statement noting if implementation of contingency measures has been triggered.
o The GME reports shall be initially reviewed by the appointed consulting firms i.e. the on-site GME report shall be directed to URS and the off-site GME report shall
be directed to AEC to ensure consistency.
o After the initial reviews both on-site and off-site GME reports should be directed to the SA EPA or appointed Auditor(s).
3.8.2 Annual Interpretative Reports
Annual reporting requirements following every second GME are as follows:
o Separate on-site and off-site Annual reports should be prepared. The reports should consolidate all results during the year and include the following:
o Groundwater level contours, flow directions, updated groundwater
gradients and flow velocities;
o Summary of field parameters and analytical results;
o Mann Kendall trend analysis;
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o Comparison against trigger levels and whether mitigation or
contingency measures have been triggered and are to be
implemented;
o Discussions on trends in groundwater elevations, plume extent,
concentrations of chemicals of concern and indicators of
biodegradation versus volatilisation in the context of the DRAs and
subsequent redevelopment activities;
o Q2 aquifer level and contamination status in relation to the potential for any impacts from the Q1 aquifer;
o Recommendations based on the monitoring results such as an
increase or decrease in the monitoring frequency, replacement of
wells, changes in analytical program and a review of the GMMP; and
o As per Section 3.8.1 annual on-site and off-site reports will be first
reviewed by the on-site/off-site consulting firms and then submitted to
the SA EPA or the Auditor(s).
3.8.3 3-year Reports
On-site and off-site data trend reports are to be completed every three years. The reporting
requirements are as follows:
o Separate on-site and off-site 3-year reports should be prepared. The reports should include the following:
o summary for groundwater levels, flow directions and flow velocities;
o Summary of field parameters and analytical results and trends;
o Discussions on plume extent, concentrations of chemicals of concern
and indicators of biodegradation versus volatilisation in the context of
the DRAs and subsequent redevelopment activities.
o Review of the GMMP and recommendations on the monitoring
frequency, replacement of wells, changes in analytical program
and/or cessation of the GMMP.
o The 3-year reports will be first reviewed by the on-site/off-site
consulting firms and then submitted to the SA EPA or the Auditors for
further reviews and approval.
3.8.4 GMMP Area Data Review and Reporting
On-site and off-site monitoring reports are to be reviewed concurrently following GMEs by the
EPA and/or EPA-accredited Auditor.
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4.0 COMPLIANCE TARGETS & TRIGGER LEVELS
4.1 Background
Compliance targets are governed by the South Australian Environment Protection Policy
[Water Quality] (EPP), 2003. Schedule 2 from the SA EPP summarises the water quality
criteria for various protected environmental values (a copy of this Schedule is provided in
Appendix B). Compliance targets adopted for this GMMP are equal to the values / criteria
presented in the SA EPP (or other sources if required). Where the abovementioned water
quality criteria have not been proposed for particular analytes, the following alternative sources
have been used:
o National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended in 2013) (NEPM).
o Australian and New Zealand guidelines for fresh and marine water quality (ANZECC, 2000).
o Australian Drinking Water Guidelines (2011) (ADWG).
o National Health and Medical Research Council Guidelines for Managing Risks in Recreational Water, 2008.
o World Health Organisation (WHO) drinking water guidelines, 2005.
The EPP does not specify criteria for recreational water quality, and defers to ANZECC (1992),
ANZECC (2000), the ADWG (2011) and other alternative sources.
ANZECC (1992) suggested that an allowance of 20 times the drinking water criteria was
appropriate for recreational waters due to the short duration and frequency of exposure, and
lesser ingestion rates compared to drinking water use. Since then, the following guideline has
been released by NHMRC - Guidelines for Managing Risks in Recreational Water (NHMRC,
2008). This document advocates a simple screening approach where —a substance occurring
in recreational water at a concentration of 10 times that stipulated in the drinking water
guidelines may merit further consideration“.
AEC considers it appropriate to adopt screening values for recreational waters as 10 times the
EPP potable criteria. As a conservative approach, this would only be applicable for inorganic
substances, and the screening value for organic compounds should be kept as the drinking
water value, to allow for possible additional effects from inhalation and dermal exposure.
Alternative criteria in the absence of EPP potable criteria include the ADWG (2004) and
NHMRC (2008). Where an aesthetic value has been used that is more conservative than the
health based value, no adjustment was made to the aesthetic criteria. Where a published
odour threshold value exists (as is the case for ammonia) in the ADWG, this value has been
adopted where it is more conservative than the 10 x Potable value.
Compliance targets for the chemicals of concern included in this GMMP and identified
beneficial uses are summarised in Table 8.
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–
Table 8 œ Adopted Groundwater Assessment Criteria (Compliance Targets)
Analyte
Assessment Criteria Groundwater
Potable Use PCR &
Aesthetics Irrigation
HSLs for Vapour
Intrusion *
General Parameters
pH 6.5 œ 8.5 - 4.5 œ 9.0 -
TDS 2,000@ - - -
Inorganic Pollutants
Nitrate (as N) 10 100 - -
Metal Pollutants
Chromium (VI) 0.05 0.5 - -
Manganese 0.5 5 2 -
Nickel 0.02 0.2 0.2 -
Zinc 3^^^ 5^^ 2 -
Organic Pollutants (TPH & BTEX)
Benzene 0.001 0.001 - 5
Toluene 0.8 0.8 - NL
Ethyl Benzene 0.3 0.3 - NL
Xylene (total) 0.6 0.6 - NL
TPH C6-C10 - - - NL
TPH >C10-C16 - - - NL
Organic Pollutants (Volatile chlorinated compounds)
1,1-Dichloroethene 0.03 0.03 - -
Cis-1,2-Dichloroethene 0.06 0.06 - -
Tetrachloroethene (PCE) 0.04 0.04 - -
Trichloroethene (TCE) 0.02~ 0.02 - -
Vinyl Chloride 0.0003 0.0003 - -
NOTE:- units of mg/L unless stated otherwise. Values are sourced from SA EPP 2003 with the exception of:-
@ SA EPA Guidelines for the Assessment and Remediation of Groundwater Contamination, 2009.
^^ In the absence of health based drinking water guidelines, ANZECC 2000 recreation guideline values have been
adopted
^^^ ADWG (Aesthetic)
* NEPM 1999 (Amendment 2013) œ based on HSL B 2m to
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It may be inappropriate to simply adopt compliance targets as trigger levels for the following
reasons:
o concentrations of chemicals of concern may require actions prior to them exceeding the compliance targets due to proximity of sensitive receptors; or
o chemical concentrations may already exceed the compliance targets but the risk assessment indicates that their concentrations do not pose an unacceptable risk
to receptors. A threshold is therefore required to manage concentrations
exceeding the compliance targets. This is to be undertaken via the application of
on-site and off-site specific trigger levels as detailed in Section 4.3.
4.2 Trigger Levels
Various triggers levels have been developed to assess changes in levels of risk from the
current situation. Mechanisms for assessing change and developing appropriate trigger levels
are summarised as follows:
o CHC concentrations (on-site) œ trigger levels are designed based on acceptable levels as determined in the on-site vapour risk assessment (see AA1 DRA) œ see
Section 4.2.2.
o CHC concentrations (off-site) and other analyte concentrations œ trigger levels are designed based on the highest reported concentrations to date as detailed in the
on-site and off-site DRAs œ see Section 4.2.2.
o Plume dynamics œ change in parent / daughter product proportions (PCE œ TCE/DCE/VC and Nitrate œ Ammonia) and plume size œ see Section 4.2.3.
o Groundwater occurrence (i.e. elevation and flow direction) œ shifts in groundwater
elevation (i.e. level rise) and flow direction may impact the current risk assessment
œ see Section 4.2.1.
4.2.1 Groundwater Level Elevations and Flow Direction – On-site
On-site groundwater elevation trigger levels are based on using a trigger of depth to water of
less than 2.0m (below ground level). This was the minimum depth to water that was
considered in the on-site vapour risk assessments.
Whilst no specific trigger levels will be adopted for the groundwater flow direction, if a
significant variation in groundwater flow direction is observed between sampling events (or
over time), then Stage 1 of the Level 2 responses should be implemented (refer Section 4.3.2).
4.2.2 Groundwater Level Elevations and Flow Direction – Off-site
Off-site groundwater elevation trigger levels are based on using a trigger of depth to water of
less than 2.0m (below ground level), the minimum depth to water that was considered in the
off-site DRA (in the sensitivity analysis). This trigger level is intended to apply particularly to
the most concentrated part of the off-site plume (in the vicinity of well MWS, based on the
monitoring results to date). Groundwater depths shallower than 2.0m below ground at
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locations where chlorinated ethene concentrations are much lower would not be associated
with increased health risks because the lower groundwater concentrations would be matched
by lower contaminant concentrations in soil vapour. Therefore, if groundwater depths less
than 2.0m are encountered at locations where the degree of groundwater impact is
substantially less than at MWS, this would not necessarily trigger further action although this
will be assessed on a case by case basis.
Whilst no specific trigger levels will be adopted for the groundwater flow direction, if a
significant variation in groundwater flow direction is observed between sampling events (or
over time), then Stage 1 of the Level 2 responses should be implemented (refer Section 4.3.2).
4.2.3 Chemicals of Concern
The development of trigger levels for the chemicals of concern adopted for this GMMP is based
on the findings of the on-site and off-site DRAs (including vapour risk assessments) conducted
for the on-site and off-site areas.
Trigger levels for CHCs have been developed for on-site and off-site based on two drivers:
1. On-site (AA1) levels (concentrations of chlorinated solvents and groundwater levels)
are based on risk associated with vapour intrusion as no relevant beneficial uses were
identified for the impacted groundwater on-site. The on-site trigger levels are based
on 80% of the maximum acceptable groundwater concentrations reported in the On-
site Vapour Risk Assessment prepared for the site. The selection of 80% is to allow
for a 20% buffer below concentrations at which potential risks are considered
unacceptable.
2. Off-site levels are based on risk associated with potential use of groundwater as a number of potential beneficial uses have been identified. The off-site trigger levels
are based on the input data used in the off-site DRA which concluded that the level of
risks are acceptable for the current groundwater elevations and chemical
concentrations (refer Section 2.2.5).
The trigger levels for the other chemicals of concern (i.e. nitrate and metals) were assigned
based on the highest recently reported concentrations (i.e. post-remediation works). The on-
site and off-site DRAs concluded that the concentrations of these chemicals do not show
increasing trends and are also likely to be stable.
Where applicable (non-CHCs), the trigger levels have been designed to allow for general
variation in reported concentrations based on the quality control requirements outlined in the
NEPM, 2013 and SA EPA Guidelines —Regulatory monitoring and testing - Groundwater
Sampling” (June 2007). Acceptable variation in reported concentrations is typically assessed
using relative percentage difference (RPD) calculated using the following equation:
RPD = ((R1-R2)/0.5*(R1+R2))*100%, where
R1 and R2 are results of testing of the samples collected from the same monitoring well.
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The accepted RPD threshold is 50%, indicating the accuracy of a sampling result is acceptable
if it meets the criterion of R1 ≤ ±1.67*R2.
Trigger levels are discussed in detail in the following subsections.
4.2.3.1 Maximum Concentrations On-site
Maximum acceptable CHC concentrations relating to vapour intrusion were calculated as part
of vapour intrusion risk assessment works. Vapour intrusion is the only identified potential
exposure pathway for AA1, trigger levels relating to potable use have therefore been excluded.
On-site CHC trigger levels are presented in Table 9.
Table 9 œ On-site Trigger Levels (Chlorinated Solvents)
Location PCE TCE cis-1,2 DCE VC
All on-site monitoring wells 68mg/L 0.8mg/L 4mg/L 0.28mg/L
Trigger levels for other relevant analytes have been based on concentrations reported to date
and are designed to include a degree of variation (i.e. allow for identification of increased
results before they reach the maximum acceptable level). The trigger levels have been
designed by adopting the 50% RPD methodology detailed above. The trigger levels for other
contaminants of concern as presented in Table 10.
Table 10 œ On-site Trigger Levels (Other chemicals)
Well ID Nitrate as N (mg/L) Nickel (mg/L)
Q1 Wells
MWC 23 CT
MWD 43 CT
MWE 200 CT
MWF CT CT
MWG CT CT
MWH 20 CT
MWJ 35 0.035
MWK 18 CT
MWM 18 CT
MWAL 35 0.040
MWAM CT CT
MWAZ 139 CT
MWBK 23 CT
MWBL CT CT
Q2 Wells
MWC_Q2 CT CT
MWH_Q2 18 CT
Notes: —CT“ œ denotes Compliance Targets (refer Table 8)
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The trigger levels for the other analytes and for the wells not listed in Tables 9 and 10 are
equal to the Compliance Targets as presented in Table 8 and Appendix B.
4.2.3.2 Maximum Concentrations Off-site
Trigger levels for CHCs off-site are based on the input data from the health risk calculations in
the off-site DRA as presented in Table 11. Table 11 shows the combination of concentrations
that were considered in the off-site DRA. Individual exceedance of some of these
concentration levels does not necessarily represent an increased health risk (especially if
concentrations of the remaining compounds are well below their trigger levels), as all four
chemicals contribute to the overall risk. The comparison of monitoring results with these
trigger levels will therefore take into account how the concentrations of each of the four
chemicals compare to the Table 11 levels, so that further action is triggered when appropriate
due to potentially increased risk levels, but is not triggered unnecessarily.
Table 11 œ Off-site Trigger Levels (Chlorinated Solvents)
Location PCE TCE cis-1,2 DCE VC
All off-site wells 1.85mg/L 0.09mg/L 0.069mg/L 0.002mg/L
As per on-site, trigger levels for non-CHCs off-site are based on the maximum post-
remediation concentrations allowing for a 50% variation as presented in Table 12.
Table 12 œ Off-site Trigger Levels (Nitrate)
Location Nitrate
All off-site wells 28.4mg/L
4.2.4 Trend Analysis
4.2.4.1 Plume Stability
Trend analysis shall be undertaken using Mann-Kendall statistical analysis for each
groundwater monitoring well in each Annual report (refer Section 3.8). The post site
remediation groundwater sampling results (starting April 2013) should be used. The trend
analysis aim is to assess for increasing/decreasing trends in the concentrations of chemicals
of concern. This assessment will allow verifying the predicted/observed stability of the plumes.
This method will also assist in applying appropriate measures when increasing trends are
estimated even before the trigger levels are exceeded.
This Mann-Kendall analysis is to be applied to all impacts. This allows for minor increases to
be noted as a ”watching brief‘. Whilst no trigger level response is warranted, these increases
(if observed) are to be noted and follow-up in the subsequent GME.
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4.2.4.2 CHC Distribution
Proportional distribution of PCE and daughter products (TCE, DCE and VC) is to be assessed
based on each individual ethene as a proportion of total ethenes (i.e. PCE+TCE+DCE+VC) to
further assess the occurrence of natural attenuation. Further assessment is triggered if there
is a greater than 30% shift if the proportion of daughter products (as individual ethenes).
4.2.4.3 Aquifer Connectivity
Q1 and Q2 elevations are to be assessed to assess potential connectivity between the two
aquifers. The adopted trigger is equilibrium between the Q1 and Q2 groundwater elevations.
4.3 Application of Trigger Levels
If the monitoring results do not exceed compliance targets for one or more analytes during
the initial three year monitoring as scheduled in the GMMP a reduction in the number of
groundwater monitoring wells and reduced set of analytes may be proposed to the
Environmental Auditor or the SA EPA following the GMMP review.
In the event that the reported concentrations of any analytes do exceed one or more the
trigger levels presented in Sections 4.2.1 to 4.2.4 then Level 1 and Level 2 of the response
measures outlined below shall be applied.
4.3.1 Level 1 – Additional Monitoring, Assessment and Review
On-site (AA1)
If the result does exceed a trigger level, then the monitoring well(s) (for which exceedances
have been reported) should be re-gauged and/or re-sampled within 3 weeks to verify the
result(s).
If the elevated result is confirmed, the following measures should be discussed and confirmed
with the SA EPA/Auditor:-
o use the new results as input data to the vapour intrusion risk assessment calculations that were used in the on-site vapour risk assessment as part of the
AA1 DRA, to assess whether the new data indicate an increased level of risk;
o if the updated risk calculations indicate an increased level of health risk, conduct an interim (quarterly) monitoring event for the subject wells and selected monitoring
wells in the vicinity;
o if the resu
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