Ethelton Stage 1 Assessment Report,March 2021
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Ethelton Stage 1 ESA South Australian Environment Protection Authority 19- Mar -2021 Doc No. R002 Ethelton Assessment Area Stage 1 Environmental Site Assessment P:\606X\60647266\400_ Technical\430_ Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA Ethelton Assessment Area Ethelton Assessment Area Stage 1 Environmental Site Assessment Client: South Australian Environment Protection Authority ABN: 85 393 411 003 Prepared by AECOM Australia Pty Ltd Level 28, 91 King William Street, Adelaide SA 5000, Australia T +61 8 7223 5400 F +61 8 7223 5499 www.aecom.com ABN 20 093 846 925 19-Mar-2021 Job No.: 60647266 AECOM in Australia and New Zealand is certified to ISO9001, ISO14001 AS/NZS4801 and OHSAS18001. © AECOM Australia Pty Ltd (AECOM). All rights reserved. AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly stated in the document. No other party should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor accepts any responsibility, to any third party who may rely upon or use this document. This document has been prepared based on the Client’s description of its requirements and AECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in accordance with sound professional principles. AECOM may also have relied upon information provided by the Client and other third parties to prepare this document, some of which may not have been verified. Subject to the above conditions, this document may be transmitted, reproduced or disseminated only in its entirety. P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA Ethelton Assessment Area Quality Information Document Ethelton Assessment Area - Stage 1 Environmental Site Assessment Ref 60647266 Date 19-Mar-2021 Prepared by Jody Elsworth / Mark Chapman Reviewed by David Steele / Mark Chapman / Paul Carstairs Revision History Authorised Rev Revision Date Details Name/Position Signature R001 3 March 2021 Draft Mark McFarlane Environment Team Lead – Geosciences and Remediation Services R002 19-Mar-2021 Final Mark McFarlane Environment Team Lead – Geosciences and Remediation Services 9 P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA Ethelton Assessment Area Table of contents Executive summary i Acronyms vii 1.0 Introduction 8 1.1 Background 8 1.2 Objectives 9 1.3 Scope of works 9 1.3.1 Modifications to proposed scope 10 2.0 Background information 11 2.1 Site setting 11 2.1.1 Site location 11 2.1.2 Zoning information 11 2.1.3 Topography 11 2.1.4 Surface water 11 2.2 Regional geology and hydrogeology 12 2.2.1 Geology 12 2.2.2 Shallow soil profile 12 2.2.3 Hydrogeology 12 2.2.4 Groundwater bore data 13 2.3 Previous investigations 15 2.4 Site history summary – former dry cleaners site 15 2.5 Observations – former dry cleaners site 16 3.0 Intrusive investigations 17 3.1 Data quality objectives 17 3.2 Overview and chronology of works 18 3.3 Preparatory works 19 3.3.1 Stakeholder engagement 19 3.3.2 Well permits 19 3.3.3 Health Safety and Environment Plan 19 3.4 Selection of investigation locations 20 3.5 Service location 20 3.6 Groundwater investigation 20 3.6.1 Groundwater well drilling and logging 20 3.6.2 Soil sampling 21 3.6.3 Groundwater well construction 21 3.6.4 Groundwater well and river gauging 21 3.6.5 Groundwater well sampling 22 3.6.6 Sample handling and laboratory analysis 22 3.6.7 Waste water disposal 23 3.7 Soil vapour investigation 23 3.7.1 Soil vapour bore installation 23 3.7.2 Soil vapour bore sampling 24 3.7.3 Waste soil disposal 24 3.8 Groundwater well and soil vapour well survey 25 4.0 Quality Assurance and Data Validation 26 4.1 Groundwater well installation and development 26 4.2 Groundwater monitoring well survey data 26 4.3 Soil vapour bore integrity 26 4.3.1 Helium leak test 26 4.3.2 Isopropanol leak test 26 4.4 Soil vapour sampling – canister pressure 26 4.5 Analytical data validation 27 5.0 Results 29 5.1 Introduction 29 5.2 Soil conditions 29 5.2.1 Observed soil profile 29 P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA Ethelton Assessment Area 5.2.2 Geotechnical laboratory testing 29 5.3 Groundwater field results 30 5.3.1 Groundwater gauging 30 5.3.2 Port River Gauging 31 5.3.3 Field indications of groundwater impact 32 5.3.4 Groundwater field parameters 32 5.4 Groundwater laboratory results 33 5.4.1 Screening criteria 33 5.4.2 Groundwater analytical results 35 5.5 Soil vapour field screening 37 5.6 Soil vapour laboratory results 37 5.6.1 Screening criteria 37 5.6.2 Soil vapour analytical results 37 5.6.3 Comparison of analytical data to field screening results 38 6.0 Discussion 40 6.1 The Presence of Site Contamination 40 6.2 Detailed assessment of volatile halogenated compound impacts 40 6.2.1 Generalised conceptual behaviour of chlorinated ethenes 40 6.2.2 Extent and magnitude of CHC groundwater contamination 43 6.2.3 Extent and magnitude of soil vapour impacts 43 6.2.4 Critical review of soil vapour and CHC groundwater data 44 6.3 Other contaminants 44 6.3.1 Petroleum hydrocarbons 44 6.3.2 Metals 45 6.4 Groundwater chemistry 45 Groundwater salinity 46 6.5 Conceptual Site Model 47 6.6 Data gaps and uncertainties 51 7.0 Vapour intrusion risk 53 7.1 Introduction 53 7.2 Toxicity Assessment 53 7.3 Quantitative Exposure Assessment 54 7.3.1 Introduction 54 7.3.2 Scope of Modelling 54 7.3.3 Estimating Exposure Concentrations 54 7.3.4 Vapour Modelling 56 7.3.5 Geological Assumptions 56 7.4 Risk Characterisation 59 7.4.1 Methods for Quantifying Risks to Human Health 59 7.4.2 Hazard Index for Threshold Effects 59 7.4.3 Acceptable Risk 60 7.4.4 Modelling Conclusions - Residential 61 7.4.5 Modelling Conclusions – Intrusive Workers 62 7.5 Sensitivity Analysis of Key Risk Modelling Inputs 63 7.5.1 Introduction 63 7.5.2 Crawl-Space Residential Dwellings 63 7.5.3 Volumetric Air Content, Moisture Content and Soil Bulk Density 64 8.0 Conclusions 66 9.0 References 68 10.0 Report limitations 70 Appendix A Figures A Appendix B Tables B Appendix C Registered bore search C P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA Ethelton Assessment Area Appendix D Plates D Appendix E Safework SA Dangerous Goods E Appendix F Well permits F Appendix G Groundwater well and soil vapour bore logs G Appendix H Calibration certificates H Appendix I Soil vapour sampling records I Appendix J Soil vapour laboratory certificates and chain of custody J Appendix K Waste disposal certificates K Appendix L Soil geotechnical analysis L Appendix M Groundwater sampling records M Appendix N Groundwater laboratory certificates and chain of custody N Appendix O Groundwater well, river stake and soil vapour bore survey results O Appendix P Analytical data validation P Appendix Q Assessment criteria Q Appendix R Vapour Modelling R P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA i Ethelton Assessment Area Executive summary AECOM Australia Pty Ltd (AECOM) was commissioned by the South Australian Environment Protection Authority (SA EPA) to conduct Stage 1 Environmental Site Assessment (ESA) works associated with the SA EPA’s Ethelton Assessment Area. The location of the Ethelton Assessment Area is shown below. □ Elhelton EPAAssessmeot Area. Stage 1 0 Former Dry Cleaning Facility The recently established Ethelton Assessment Area encompasses a predominantly residential area surrounding the former Bronsons Dry Cleaners site at 10-12 Marion Street, Ethelton. A Section 83A notification for 12 Marion Street was submitted to the SA EPA on 25 August 2020 by Environmental Projects Pty Ltd, who were undertaking environmental assessment work at the property. The notification reported chlorinated hydrocarbon compounds (CHCs) in shallow soil and groundwater at the 10-12 Marion Street site (EPA, 2021). The SA EPA commissioned this Stage 1 investigation with the following specific objectives: • Investigate the nature and extent of chlorinated hydrocarbon compounds in soil vapour external to the 10-12 Marion Street site. P:\606X\60647266\400_Technical\430_Technical Working Documents\Report\20210319 SA EPA Ethelton Stage 1 Assessment Report.docx Revision R002 – 19-Mar-2021 Prepared for – South Australian Environment Protection Authority – ABN: 85 393 411 003 AECOM Ethelton Stage 1 ESA ii Ethelton Assessment Area • Investigate the nature and extent of chlorinated hydrocarbon compounds and other key contaminants in groundwater external to the 10-12 Marion Street site.