GROUNDWATER MONITORING & MANAGEMENT PLAN · groundwater wells (see Figures 3 and 4). The locations...

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: [email protected] Web: www.aecaust.com.au

www.aecaust.com.au

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)

i

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



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



ii

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.



1

http://www.epa.sa.gov.au

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



2

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.



3

Figure 3 œ Groundwater Investigation Monitoring Well Network



4

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.



5

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.



6

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).



7

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.



8

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.



9

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.



10

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.



11

Figure 4 œ Groundwater Contamination Plumes (URS and AEC October 2014 data)



12

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).



13

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).



14

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.



15

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.



16


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



17


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



18


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.



19

–

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



20

–

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



21

Figure 5 œ GMMP Monitoring Wells



22

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.



23

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.



24

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



25

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.



26

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.



27

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).



28

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:



29

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;



30

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.



31

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.



32

–

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

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



34

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.



35

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)



36

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.



37

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

GROUNDWATER MONITORING & MANAGEMENT PLAN · groundwater wells (see Figures 3 and 4). The locations...

Documents

Transcript of GROUNDWATER MONITORING & MANAGEMENT PLAN · groundwater wells (see Figures 3 and 4). The locations...