Remedial Action Plan

Transcription

1 Remedial Action Plan for Leichhardt Park - Mary Street Lilyfield NSW 4 Prepared for: Leichhardt Municipal Council Revised July, (Report: C64Q37B333 Leichhardt Park RAP FC) COPYRIGHT: The concepts, information and design ideas contained in this document are the property of Sydney Environmental & Soil Laboratory Pty Ltd (ABN ) Use or copying of this document in whole or in part without the written permission of Sydney Environmental & Soil Laboratory constitutes an infringement of copyright

2 EXECUTIVE SUMMARY SESL Australia (SESL) was engaged by Leichhardt Municipal Council (the client) to prepare this Remedial Action Plan (RAP) for Leichhardt Park, Lilyfield (the site) The site encompasses Lot 6643, DP This report will be used as supporting documentation for a development application for the proposed childcare centre development The site is currently used as an open public space (park) Based on the concept drawings provided by Council to SESL, Council intends to develop a childcare centre with access to soils Previous investigations on the site identified that existing soils on the site are not considered suitable for a childcare centre due to elevated levels of carcinogenic polycyclic aromatic hydrocarbons (CPAHs) in the surface soils, and therefore remediation must occur before the site can be considered suitable for the proposed use The objective of this RAP is to prescribe appropriate remedial actions that, once concluded, will render the site suitable for the proposed childcare centre This RAP was developed based on the information contained in the previous investigations available for the site An assessment of potential remediation options considered that On-site Management (isolation) of soil impacted by Carcinogenic Polycyclic Aromatic Hydrocarbons (CPAH) was considered appropriate This method involves ensuring a physical barrier between the contaminant source and potential receptors The method can be concurrently delivered during the redevelopment of the site, can be delivered effectively with minimal alteration to design, is cost effective by retaining materials on site and meets the remediation objectives of being protective of future site users SESL concludes that the isolation of future site users from contact with site soils will achieve the objectives of the RAP and render the site suitable for the intended childcare uses Documentation of the success of remediation is required in a subsequent Site Remediation and Validation Report (SRVR) at the conclusion of remedial works A long term Environmental Management Plan (EMP) will be required to ensure the site remains suitable for future users, workers and visitors to the site Reference should be made to Section of the report that sets out details of the limitations of the assessment SESL AUSTRALIA Kelly Lee Environmental Scientist Ryan Jacka Senior Environmental Scientist Leichhardt Municipal Council Page of 43

3 TABLE OF CONTENTS! INTRODUCTION!! BACKGROUND!! OBJECTIVES! 3! STAKEHOLDERS 6! 4! OUTLINE OF THE RAP 6!! SITE DESCRIPTION 7!! SITE IDENTIFICATION 7!! SURROUNDING LAND USE 8! 3! SITE LAYOUT AND INFRASTRUCTURE 8! 4! PHYSICAL SITE CHARACTERISTICS 9!! SITE HISTORY! 6! SITE ZONING AND PLANNING ISSUES! 7! EPA CONTAMINATED SITES DATABASE! 8! SUMMARY OF PREVIOUS INVESTIGATIONS! 9! INTEGRITY ASSESSMENT 3!! EXTENT OF REMEDIATION 3! 3! CONCEPTUAL SITE MODEL 4! 3! SOURCES OF IMPACT 4! 3! CONTAMINANTS OF CONCERN 4! 33! FATE AND TRANSPORT 4! 34! POTENTIAL SURROUNDING RECEPTORS! 4! REMEDIATION DESIGN 6! 4! REMEDIATION AREA 6! 4! REMEDIATION GOAL AND PURPOSE OF RAP 6! 43! REMEDIATION ACCEPTANCE CRITERIA 6! 44! RATIONALE BEHIND THE SELECTION OF REMEDIATION STRATEGY 8! 4! PREFERRED REMEDIAL OPTION! 46! COMPLIANCE WITH REGULATORY REQUIREMENTS!! REMEDIATION METHODOLOGY 3!! OVERVIEW 3!! REMEDIATION METHODOLOGY 3! 6! VALIDATION! 6! ENVIRONMENTAL CERTIFICATION! 6! VALIDATION SAMPLING REGIME! 63! WASTE CLASSIFICATION AND DISPOSAL CERTIFICATION 6! 64! SITE REMEDIATION AND VALIDATION REPORT 6! 6! ENVIRONMENTAL MANAGEMENT PLAN 7! 7! SITE ENVIRONMENTAL CONTROLS 8! 7! OVERVIEW 8! 7! WORK PROCEDURES 8! 73! EROSION, SEDIMENT AND SURFACE WATER MANAGEMENT 3! 74! NOISE AND VIBRATION CONTROL MEASURES 33! 7! EQUIPMENT CLEANING AND OPERATION 33! Leichhardt Municipal Council Page of 43

4 76! STOCKPILES 33! 77! REMEDIATION SCHEDULE 34! 8! CONTINGENCY PLANNING 36! 8! OVERVIEW 36! 8! INCREASED VOLUMES OF MATERIAL 36! 83! REMOVAL OF CONTAMINATED MATERIALS 36! 84! UNKNOWN TYPES OF MATERIALS / UNEXPECTED FINDS 36! 8! EXCESSIVE ODOUR OR VAPOURS 37! 86! OTHER CONTINGENCY MEASURES 37! 9! WORK HEALTH & SAFETY 38!! COMMUNITY CONSULTATION & LIAISON 39!! CONCLUSION 4!! LIMITATIONS 4! 3! REFERENCES 4! DOCUMENT TABLES Table Stakeholders 6! Table Site Identification 7! Table 3 - Summary of Soil Results! Table 4 Remediation Acceptance Criteria 8! Table Assessment of Potential Remediation Options! DOCUMENT FIGURES Figure Locality Map Leichhardt Park, Mary Street, Lilyfield 8! Figure Site Layout Leichhardt Park, Mary Street, Lilyfield 9! APPENDICES Appendix A Appendix B Map Site Layout and Sample Locations Map and 3 Final Construction Plans Soil Analytical Results Leichhardt Municipal Council Page 3 of 43

5 ABBREVIATIONS ACM Asbestos Containing Material ASC NEPM 3 National Environment Protection (Assessment of Site Contamination) Measure 999 (April 3), NEPC 3, Canberra AEC Areas of Environmental Concern AHD Australian Height Datum ANZECC Australian and New Zealand Environment and Conservation Council BTEX Benzene, Toluene, Ethylbenzene, and Xylenes CPAH Carcinogenic Polycyclic Aromatic Hydrocarbon CSM Conceptual Site Model DEC Department of Environment and Conservation DECCW Department of Environment, Climate Change and Water NSW DP Deposited Plan DSI Detailed Site Investigation EILs Ecological Investigation Levels EMP Environmental Management Plan ENM Excavated Natural Material EPA Environment Protection Authority ESLs Ecological Screening Levels HILs Health Investigation Levels HSLs Health Screening Levels NATA The National Association of Testing Authorities NEHF National Environment and Health Forum NEPC National Environment Protection Council NEPM National Environment Protection Measure OCP Organochlorine Pesticides OEH Office of Environment and Heritage NSW OPP Organophosphorus Pesticides PAH Polycyclic Aromatic Hydrocarbons PCB Polychorinated Biphenyls PPE Personal Protective Equipment POEO Protection of the Environment Operations PSI Preliminary Site Investigation RAC Remediation Acceptance Criteria RAP Remedial Action Plan SESL SESL Australia SMP Site Management Plan SWMS Safe Work Method Statement SRVR Site Remediation and Validation Report TRH Total Recoverable Hydrocarbons UCL Upper confidence Limit VENM Virgin Excavated Natural Material WHS Work, Health and Safety Leichhardt Municipal Council Page 4 of 43

6 INTRODUCTION BACKGROUND SESL Australia (SESL) was engaged by Leichhardt Municipal Council (the Client) to prepare a Remedial Action Plan (RAP) for Leichhardt Park Mary Street, Lilyfield NSW (the site) The site encompasses a portion of Lot 6643, DP The site is currently used as an open public space with children s plan equipment Based on the concept drawings provided by Council to SESL, Council intends develop a childcare centre on the site, which will include open outdoor spaces of exposed soil Previous investigations on the site identified that existing soils on the site are not considered suitable for a childcare centre due to elevated levels of carcinogenic polycyclic aromatic hydrocarbons (CPAHs) in the surface soils, and therefore remediation must occur before the site can be considered suitable for the proposed use The remediation works prescribed in this RAP shall be undertaken by the contractor selected and engaged by the developer of the childcare centre and will require validation by an appropriately qualified Environmental Consultant following completion of works A long term Environmental Management Plan (EMP) will be required to ensure the site remains suitable for future users, workers and visitors to the site It has been acknowledged that some trees located on the site have considerable landscape and environmental significance, and as such this report makes recommendations with the preservation of these trees in mind OBJECTIVES The overall objective for the remedial works is to prescribe appropriate remedial actions that, once concluded, will render the site suitable for the proposed childcare centre To achieve this objective, the RAP has been designed to: Provide a plan of remediation for the site to reduce unacceptable risk of contamination to impact on human and ecological health; Establish remediation acceptance criteria that are appropriate for a childcare centre in the context of the identified contamination; and Demonstrate that the proposed remediation strategy is compliant with state and local government and planning statutes and compliant with NSW EPA endorsed guidelines under Section of the Contaminated Land Management Act 997 and properly addresses issues relating to site environmental management, community relations and contingency planning Leichhardt Municipal Council Page of 43

7 3 STAKEHOLDERS The key stakeholders involved in the implementation of the RAP are provided in Table Table Stakeholders Stakeholder Property Owner/Developer Remediation Contractor Civil Works Contractor Environmental Consultant Leichhardt Municipal Council 4 OUTLINE OF THE RAP The RAP has been developed under the guidance of the appropriate regulatory framework endorsed by the NSW Environment Protection Authority (EPA) and complies with the provisions of the NSW Contaminated Land Management Act 997 and associated guidelines and regulations The RAP will discuss the following: Site description; Summary of previous investigations and previous results: Site condition and surrounding environment; Conceptual Site Model; Remediation design and acceptance criteria; Remediation methodology; Validation; Site environmental controls; Contingency planning; Work health and safety; and Community consultation and liaison Leichhardt Municipal Council Page 6 of 43

8 SITE DESCRIPTION SITE IDENTIFICATION The site access is currently from Mary Street, Lilyfield NSW The investigation area where the proposed development is to occur is approximately,m and comprised of Lot 6643, DP The site is on the western side of Mary Street, immediately north of the northern most residential allotment on the street A historical title search was carried out as part of the PSI conducted by ADE Consulting The results of this search indicate that the site is currently Crown Land, owned and managed by the State of New South Wales Refer to Appendix II of the PSI report developed by ADE Consulting for further information Table Site Identification Site Owner The State of New South Wales Site Address Mary Street, Lilyfield NSW Lot and DP Number Lot 6643, DP Local Government Area Leichhardt Municipal Council Current Zoning Public Recreation (Leichhardt LEP, 3) Geographical Coordinates 33 '6" S 9'39" E Investigation Area Approximately,m in total Site Elevation Approximately m AHD Locality Map Figure Site Layout Figure Leichhardt Municipal Council Page 7 of 43

9 Figure Locality Map Leichhardt Park, Mary Street, Lilyfield Figure : Locality Map Investigation area: ~,m (Source: Land and Property Information, Department of Finance and Services ) SURROUNDING LAND USE The site is located within a mixed-use area with residential and commercial area located to the southern side of the site and parkland and light commercial to the north, east and west of the site Iron Cove is located to the far west of the site The site is immediately north of the northern most residential allotment on Mary Street 3 SITE LAYOUT AND INFRASTRUCTURE The site layout can be viewed in Figure The site is an existing public open space with children s play equipment in the northeast corner The site has been levelled with fill materials and drops away steeply to the southwest and west Large established trees border the open, grassed area The northern boundary is a car park and Mary Street is located to the east of the site SESL understands that the playground in the northeast corner will be retained Leichhardt Municipal Council Page 8 of 43

10 Figure Site Layout Leichhardt Park, Mary Street, Lilyfield Figure : Site Layout Investigation area: ~,m (Source: Land and Property Information, Department of Finance and Services ) 4 PHYSICAL SITE CHARACTERISTICS 4 Topography and Drainage The elevation across the investigation area is approximately meters (m) Australian Height Datum (AHD) This level is raised above the natural elevation of the area, as the area has been filled historically Fill depth increases from east to west to create a flat area contrary to the flow of the original topography to Iron Cove 4 Geology The Soil Landscapes of the Sydney : Sheet Map (Chapman et al 989) indicates the site to be within the Hawkesbury Soil Landscape, however the soil observed on the site is not consistent with the natural soils of this landscape group due to the filling that has occurred previously See borelogs from previous investigations for more information on the soil profile observed on the site Iron Cove is the closest natural water body, and is located approximately 3 metres to the west of the site Groundwater flows are expected to be in fractured rock underlying the site, flowing in a westerly direction, towards Iron Cove Leichhardt Municipal Council Page 9 of 43

11 43 Acid Sulfate Soil ADE Consulting identified an acid sulfate soils risk during the PSI due to the site s proximity to an area of Class, however due to the highly modified (constructed) soil profile of the site it is not expected that acid sulfate soils are present Further, the site is underlain by Hawkesbury sandstone and is in a ridge position of significant elevation (m), supporting the claim that acid sulfate soils are not present 44 Proximity to Local Sensitive Environments Iron Cove (Parramatta River) is located approximately 3 metres west of the site No water body or other sensitive environment has been identified within the site The areas surrounding the site are heavily developed and as such no sensitive environments have been identified in those areas SESL has been advised by Council that the established vegetation around the site is considered significant to the local environment and is to be retained 4 Soil and Groundwater Contamination No previous record of soil or groundwater contamination was identified for the site from available records SITE HISTORY A review of the site history was undertaken by ADE Consulting during the PSI and reviewed by SESL to assess historical use of the site, and in particular to identify activities with potential to contaminate soil or groundwater at the site The historical review included: Historical Certificates of Title; Other available historical site information; and Historical Aerial Photographs There has been no history of development on the site The historical title review shows the site to have been crown land with zoning to support uses for recreational purposes Aerial photographs show some early disturbance of the area in the 943 photograph, however no evidence of developments or demolitions to suggest sources of contamination 6 SITE ZONING AND PLANNING ISSUES Leichhardt Local Environmental Plan 3 is the principle-planning instrument regulating landuse and development in the area The site is zoned as Public Recreation and the objectives for this zone is as follow: To enable land to be used for public open space or recreational purposes To provide a range of recreational settings and activities and compatible land uses To protect and enhance the natural environment for recreational purposes Leichhardt Municipal Council Page of 43

12 To maximise the quantity and quality of open space areas to meet the existing and future needs of the community To ensure the equitable distribution of, and access to, open space and recreation facilities To provide links between open space areas 7 EPA CONTAMINATED SITES DATABASE A search of the NSW Environmental Protection Authority (EPA, now incorporated into the Office of Environment and Heritage) public register of Notices issued under the Contaminated Land Management Act 997 was undertaken by ADE Consulting during the PSI and confirmed by SESL This indicated that no notices have been issued against the site or the surrounding properties Please refer to the ADE Consulting Report Titled Phase Preliminary Site Investigation Leichhardt Park Mary Street, Lilyfield NSW for the results of this review 8 SUMMARY OF PREVIOUS INVESTIGATIONS 8 ADE Consulting conducted a Preliminary Site Investigation (PSI) for Leichhardt Park in November 3 (Refer to ADE Consulting Report Titled Phase Preliminary Site Investigation Leichhardt Park Mary Street, Lilyfield NSW ) The assessment was conducted to preliminary characterise the contamination status of the site for the proposed development of a childcare centre The conclusions of the report were: The land was dedicated for public recreation in Gov Gaz Dated 9977 and was deemed a reserve within the meaning of Part of the Crown Lands Act 989 Large developments bordering the site have been constructed and demolished, indicating potential fill materials may exist on site The site was vacant at the time of inspection, with the exception of the caretaker s cottage and children s play equipment ADE has been advised that the proposed development is a childcare centre It is the opinion of ADE that there is potential for contaminated fill materials on site Due to the sites close proximity to an area indicated as a Class risk of acid sulphate soils, there is potential for acid sulphate soils to be present on site The potential contamination types that were identified for the site include: Asbestos Containing Materials, Heavy metals, BTEX, PAHs, TPHs, OCPs, OPPs and Phenols A Limited Phase II Detailed Site Contamination Investigation should be undertaken to determine whether contamination is present within the soil Leichhardt Municipal Council Page of 43

13 8 SESL Australia conducted a Tier Detailed Site Investigation for the Site This investigation was designed to identify the presence of soil contamination identified as potentially present in the PSI as developed by ADE Consulting 83 The investigation identified that: The fill of unknown origin contains carcinogenic PAH s in concentrations that exceeds the ASC NEPM 3 Health Investigation Levels for Residential A as tabulated in Table 3 (see Appendix B) No asbestos containing materials were identified in the proposed works area, however were identified in the region of trees around the south and west In order for the site to meet the requirements of the guidelines and suitable for the proposed development, remediation of site soils would be required Remediation must be completed in accordance with a Remedial Action Plan prepared by a qualified environmental consultant Table 3 - Summary of Soil Results Carcinogenic PAHs HIL Residential A 3 BH - Surface 89 BH Surface 87 BH Surface (Dup) 83 BH3 Surface 3 BH3-3mm 3* BH4 Surface 6 BH4-3mm 379* BH Surface 4 BH6 - Surface 84 BH7 Surface Average Minimum 89 Maximum 6 Standard Deviation 6 9% UCL 39 Note: Bold values indicate values above the adopted HIL-A * Values not included in calculations for surface soils Leichhardt Municipal Council Page of 43

14 9 INTEGRITY ASSESSMENT The integrity of information provided in the previous investigations, published reports and from the site walkover was considered reliable Details regarding the site history and present status of the site have been largely obtained from official records sourced from Leichhardt Municipal Council, EPA and NSW Land and Property Information under Department of Finance and Services Additional information was obtained from previous environmental investigations and published records to identify the historical information related to this site These documents are considered accurate and credible All information provided as part of this report was believed to be true, accurate and representative of the past and present status of the site at the time of this investigation EXTENT OF REMEDIATION Based on the findings of the previous investigations, the contaminated materials requiring management under this RAP are surface soils contaminated with Carcinogenic PAHs This is soil that is chemically contaminated due to former land filling activities Due to the previous investigations looking at surface distribution of contaminants, SESL has adopted a conservative approach that considers that all site soils are not suitable for the sensitive intended use Furthermore, although asbestos was not identified across the region of proposed works, there is a potential for asbestos containing materials (ACM) to be buried within the fill profile, and therefore should be included in the remedial strategy Leichhardt Municipal Council Page 3 of 43

15 3 CONCEPTUAL SITE MODEL A conceptual site model (CSM) was developed based on the information obtained during the investigation process to allow assessment of potential sources of impact, chemicals of concern, transport mechanism and receptors 3 SOURCES OF IMPACT In summary, the sources of impact identified in the assessment area include: Historically imported filled material of unknown source 3 CONTAMINANTS OF CONCERN Based on the potential sources and the findings of the current investigation, the contaminants of concerns include the following: Carcinogenic Polycyclic Aromatic Hydrocarbons Asbestos containing materials in deeper fill layers 33 FATE AND TRANSPORT 33 Transport Medium and Control The anticipated primary transport media for the migration of contaminants of concern are: Migration of contaminated material through erosion and dust during construction works: o Remedial Action as recommended in Section Surface runoff to stormwater drainage system containing CPAHs: o No stormwater flow through proposed area of disturbance Contaminants migrating to groundwater table beneath the site: o The identified contaminants are present in the fill material, which is located several metres above the natural groundwater level Given that the site is located atop the fill material, which is capping any natural soil layers, it is considered unlikely that any contaminated groundwater will impact the site or that any excavation of contaminated soil will affect the groundwater 33 Potential Migration Pathways There are a number of mechanisms by which identified receptors may come into contact with contaminated sources, including the following: Incidental dermal contact or ingestion of impacted soils o Proposed remediation prevents contact with site soils Generation of impacted dusts, aerosols or sediments from impacted soils o Environmental controls throughout remediation manages risk, final site condition prevents the generation of dusts Leichhardt Municipal Council Page 4 of 43

16 Groundwater migration: o The area of proposed disturbance is not within the vicinity of groundwater and therefore there is little risk of groundwater migration Surface runoff and stormwater drainage system: o There is no significant stormwater flow through the area of proposed disturbance 34 POTENTIAL SURROUNDING RECEPTORS The potential human receptors are as follow: Construction workers during construction being exposed to contaminated soil: o Some exposure will occur throughout the construction process if remediation techniques are not utilised prior to construction Community members living within vicinity of the site: o Some erosion may result in exposure if remediation techniques are not used prior to construction Visitors to the site: o Exposure may occur if remediation techniques are not used prior to construction Future occupants of the developed site: o Exposure may occur if remediation techniques are not used prior to construction Leichhardt Municipal Council Page of 43

17 4 REMEDIATION DESIGN 4 REMEDIATION AREA Interpretation of results from the contamination investigation identified that the fill material is not consistent across the site, and as such the entire development area must be treated as potentially contaminated Samples analysed from below the ground surface did not indicate that contaminant levels decreased with depth, which suggests that the contamination is the result of filling and not anthropogenic activities on the current ground surface It is noted that ash materials were identified in the surface soil, likely contributing to the observed contamination It is considered that ash material, along with other building wastes such as brick and concrete, pose a further aesthetic consideration for the proposed use The full extent of contamination below ground has not been delineated, and therefore the effectiveness of remedial options that consider the removal of contaminants, as discussed below, are not considered practical 4 REMEDIATION GOAL AND PURPOSE OF RAP The goal for the remediation of the site is to render the site suitable for the development of a childcare centre The purpose of this RAP is to: Provide a plan of remediation for the site to reduce unacceptable risk to human health and/or ecosystems and remove aesthetically unacceptable conditions; Establish remediation acceptance criteria that are appropriate for the development of a childcare centre in the context of the identified contamination; and Demonstrate that the proposed remediation strategy is compliant with state and local government and planning statutes and compliant with NSW EPA endorsed guidelines under Section of the Contaminated Land Management Act 997 and properly addresses issues relating to site environmental management, community relations and contingency planning 43 REMEDIATION ACCEPTANCE CRITERIA In consideration of appropriate isolation, the Remediation Acceptance Criteria (RAC) includes: All existing site soils placed below concrete slab; and/or All existing site soils covered with geosynthetic marker layer and covered with minimum 3mm imported media Leichhardt Municipal Council Page 6 of 43

18 43 Health and Ecological Investigation Levels (HILs and EILs) Remediation Acceptance Criteria (RAC) have been derived from Schedule B(): Guideline on Investigation Levels for Soil and Groundwater (ASC NEPM 3) The guideline provides both Health Based Investigation Levels (HILs) and Ecological Investigation Levels (EILs) HILs are given in the ASC NEPM 3 for four (4) general exposure settings, with the most appropriate exposure setting being: A Residential with garden/accessible soil (home grown produce contributing less than % of vegetable and fruit intake; no poultry) this category includes children s day-care centres, preschools and primary schools Due to proposed use as a childcare centre, high human exposure to the site is expected if left in its current condition Therefore the HILs that are appropriate for the site is the most stringent HIL, ASC NEPM 3 HIL A criteria for residential landuses As the proposed remedial method proposes the importation of growing media, no EILs have been adopted The ultimate objective of the remediation works is to have no existing site soil accessible As such, the primary criteria for assessing the effectiveness of remediation is the witness points of the isolation materials, both in the form of concrete and imported growing media The adopted RAC are presented in Section Aesthetic Guidelines The ASC NEPM 3 Schedule B() Guideline on Investigation Levels for Soil and Groundwater, advise that aesthetic issues generally relate to the presence of low-concern or non-hazardous inert foreign material (refuse) in soil or fill resulting from human activity These may be present on sites that have been assessed as being acceptable from a human health and environmental perspective, and should still be considered in regards to suitability for the proposed landuse As foreign materials were observed in previous investigations, it is concluded that these would be an aesthetic concern if allowed to remain in the soil surface Due to the proposed remediation method, it is considered that all aesthetic risks will be mitigated along with the health risks 433 Adopted Remediation Acceptance Criteria Derived from the ASC NEPM 3, the adopted remediation acceptance criteria (RAC) for the contaminants identified on the site are discussed below and presented in Table 4 The analytical RAC will apply to all imported materials to be placed in areas with potential for direct contact with future site users Leichhardt Municipal Council Page 7 of 43

19 Carcinogenic PAH s: CPAH s have been identified at concentrations warranting remediation in soils to reduce human health risk As the contaminated materials will be isolated from site users and the analytical RACs are proposed for the imported materials, a broader contaminant suite has been adopted An acceptable result will be all samples showing compliance with the RAC, with no consideration of 9% UCL or other statistical calculations accepted Table 4 Remediation Acceptance Criteria Contaminant( RAC( Guideline(Reference( Total&PAHs& 3&mg/kg& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& CPAHs& 3&mg/kg&& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Arsenic& & ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Cadmium& & ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Chromium& & ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Lead& 3& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Mercury& 4& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Nickel& 4& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Copper& 6& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& Zinc& 74& ASC&NEPM&3& &Schedule&B&Table&A()&HIL&A& In consideration of appropriate isolation, the RAC includes: All existing site soils placed below concrete slab; and/or All existing site soils covered with geosynthetic marker layer and covered with minimum 3mm imported media 44 RATIONALE BEHIND THE SELECTION OF REMEDIATION STRATEGY The selection of a remediation strategy for the site was undertaken in consideration of the contaminants being remediated, the extent of the remediation area and the intended landuse Other considerations included the time required to achieve remediation, other impacts of remediation such as ecological or aesthetic values and overall cost 44 Evaluation of Remediation Options The preferred order of options for site remediation and management is given by the ANZECC/ NHMRC (99) guidelines as: On site treatment of the soil so that the contaminant is either destroyed or the associated hazard is reduced to an acceptable level; and Off site treatment of excavated soil so that the contaminant is either destroyed or the associated hazard is reduced to an acceptable level, after which the soil is returned to the site If these options cannot be implemented other options can be considered including: Leichhardt Municipal Council Page 8 of 43

20 Removal of contaminated soil to an approved site or facility, followed by where necessary by replacement of clean fill; or Consolidation and isolation of the soil on site by containment within a properly designed barrier The above guidance can be summarised as the following potential remediation options for the site: On-Site Treatment; Excavation and Disposal; On-Site Management; and Do Nothing The assessment of the suitability of potential remediation options as discussed was made based on environmental impacts, time constraints, site logistics and cost A description of each option is provided below with the assessment of each option summarised in Table 44 On-Site Treatment On-site treatment methods include both in-situ and ex-situ treatments of soils Treatment may be chemical, mechanical or biological On-site treatments have the advantage of sometimes being relatively cheaper than off site landfilling For the contaminants driving remediation on this site, biological treatment is not practical Chemical and mechanical treatments falls under the category of solidification and stabilisation This type of treatment retains immobilised contaminants on the site, but usual results in constraints to development of the affected portion of the land also requires implementation of an on-going Environmental Management Plan 44 Excavation and Disposal Excavation of the contaminated fill material would be required for off site disposal This option removes the contaminated materials through bulk excavation into trucks that then transfer the contaminated materials to a waste facility with appropriate licenses to receive the waste 443 On-Site Management - Isolation On-site management of the contamination involves selective remediation across the site to reduce the impact to human health or the environment and long-term management of any remaining contamination The strategy comprises the construction of an appropriate encapsulation system, which may range from the placement of the capping layer over the contaminated material, to an engineering containment cell, to a permanent barrier isolating the contaminated material The site would then require a site-specific ongoing Environmental Management Plan (EMP, also known as Site Management Plan - SMP) to control the exposure of the contamination to future owners, workers and visitors to the site and potential future users of the site 444 Do Nothing The Do Nothing involves leaving hazardous materials, contaminated soil and aesthetically unacceptable materials in their current locations and proposes the development without concern for the remediation of contaminated soils Leichhardt Municipal Council Page 9 of 43

21 Table Assessment of Potential Remediation Options Remediation Option On-Site Treatment Excavation and Disposal On-Site Management Do Nothing Discussion SESL considers that the contaminated soil materials These materials may be suitable for on-site treatment such as solidification and stabilisation This approach is considered unacceptable for this site, as the vertical extent of the contamination is undetermined due to the variability of the fill material on site There is a potential for asbestos contamination which would pose a significant variation in disposal fees and the overall depth of required excavation is not known Furthermore, greater importation of materials would be necessary and would require greater validation effort This approach is considered suitable for contaminated soil materials as the contaminated material will be permanently barricaded, limiting exposure and access to users of the site The disadvantages of such a strategy would be the imposing of an ongoing EMP, associated notification obligations on the land title and ongoing monitoring and inspection of the site for compliance with the EMP The strategy can be implemented in a variety of ways to fit with construction techniques and suit all areas of the proposed development Areas requiring remediation are at the ground surface and exposed The future use of the site would be affected by the presence of uncovered contaminated materials and would not be suitable for sensitive land use The areas of concern could pose a potential health risk to workers during development of the site and users to the site The areas of concern at the surface exceed the adopted landuse criteria and are not considered acceptable for ongoing use without remediation or management being undertaken The identified contaminants are known to be persistent in the environment and will pose a long-term health and Conclusion This option is considered partially suitable for CPAH, however it is considered impractical as the full extent of soils requiring treatment is not known and is not effective for aesthetic concerns, which may also include asbestos This option is considered unsuitable for this remediation project due to associated costs If final levels require the removal of some soil quantity, classification prior to disposal will be required This option is considered suitable for this remediation project It prevents the unnecessary removal of an unknown quantity of contaminated soil and allows the soil containing the landscape significant trees to remain on-site This option is considered inappropriate Leichhardt Municipal Council Page of 43

22 environment hazard if left on the site in their current state 4 PREFERRED REMEDIAL OPTION Following the assessment of options discussed above, SESL recommends that the most appropriate remedial option is On-site Management (isolation) This method involves ensuring a physical barrier is between the contaminant source and potential receptors The method can be concurrently delivered during the redevelopment of the site, can be delivered effectively with minimal alteration to design, is cost effective by retaining materials on site and meets the remediation objectives of being protective of future site users 46 COMPLIANCE WITH REGULATORY REQUIREMENTS 46 Environmental Planning and Assessment Act and Regulations Remedial works at the site are not considered to present a designated development under Schedule 3 of the Environmental Planning and Assessment Act 979 Furthermore, the program of rehabilitation works described in this RAP has been designed so that works shall not adversely affect the environment and will be an improvement to the environment For these reasons the remediation works should not require the preparation of an Environmental Impact Statement (EIS) 46 State Environmental Planning Policy (SEPP No Remediation of Land) The objective of this planning policy is to provide a state-wide planning approach to the remediation of contaminated land In particular the policy aims to promote the remediation of contaminated land for the purpose of reducing risk of harm to human health or any other aspect of the environment The planning policy applies to this site because the site is categorised as Category Remediation Work and Section 44 requires 3 days written notice to be submitted to Council before the commencement of remediation works 463 Leichhardt Development Control Plan No 4 Contaminated Land Management The key principles of the DCP are to: Ensure that changes of land use will not increase the risk to health or the environment; Avoid inappropriate restrictions on landuse; and Provide information to support decision making and to inform the community This RAP meets the objectives of the DCP with the aligned goal of remediating the site in a socially acceptable and cost effective manner which mitigates threats to, and provides protection for, public health, welfare and the environment while allowing flexibility in future use of the site Leichhardt Municipal Council Page of 43

23 464 NSW Protection of the Environment Operations Act 997 The objective of the Act relevant to this RAP is to protect, restore and enhance the quality of he environment in NSW, having regard to the need to maintain ecologically sustainable development and to increase opportunities or public involvement and participation in environmental protection The Act prohibits the contamination of land through any means including the improper application of waste and prescribe the requirements for triggering which sites require an environmental protection license to operate The objectives of the RAP align with the Act by focusing on an improved human and environmental amenity of the site and providing details of community consultation requirements Leichhardt Municipal Council Page of 43

24 REMEDIATION METHODOLOGY OVERVIEW Remediation works at the site will involve On-Site Management (Isolation) for soil impacted by Carcinogenic Polycyclic Aromatic Hydrocarbons (CPAH) A suitably qualified environmental consultant must be engaged to direct the remediation works and undertake validation of remediation works as required SESL s preferred methodology for the remediation works is discussed in the following sections In summary, the remediation end goal is to have: All existing site soils placed below concrete slab; and/or All existing site soils covered with geosynthetic marker layer and covered with minimum 3mm imported media REMEDIATION METHODOLOGY On-site management (isolation) of contaminated materials is the preferred option for the remediation of the site The region contains elevated CPAH concentration and may contain other physical contaminants at depth, potentially ACM The Remediation Contractor who undertakes the remediation work must prepare a work method statement incorporating relevant sections of this RAP into a work methodology The indicative work methodology can be summarised as follows: Establishment: a Works should be supervised by an appropriately qualified environmental consultant to observe and document that the contaminated material is appropriately contained on site Isolation of Contaminated Materials: a Where soils are to remain exposed (ie outdoor grass play areas and garden beds), 3mm of existing site soils must be removed (cut) from the current surface This material must be classified in accordance with the NSW Waste Classification Guidelines if disposed of off-site This material may be used as fill in other areas, conditional to the fact that the final resting place meets the conditions of this RAP It is noted that 3mm will be sufficient for proposed turf areas Areas of garden beds or tree planting may require deeper soil depth The contractor must have all landscape plans reviewed by an appropriate horticultural soil scientist to ensure remediation depths match the requirements for landscape planting b A semi-permeable marker layer (geotextile fabric) must be placed atop the exposed existing site soils c Imported soils must be suitable for the intended use (ie turf underlay or garden soil) from a horticultural perspective, but also meet the RAC Imported engineering fill must meet the Excavated Natural Material Order (EPA, 4) or VENM definition of POEO Leichhardt Municipal Council Page 3 of 43

25 Act 997 All compliance certificates for imported materials must be approved by the supervising consultant d The overall level of the site soils should not exceed that of the ground level prior to the commencement of the remediation Intentionally landscaped mounds and structural fill may exceed the pre-existing ground level e In areas where an impermeable surface (ie concrete slab) will cover existing site soils, the construction of the slab will suffice as an effective isolation No additional remedial activities will be required in these areas Leichhardt Municipal Council Page 4 of 43

26 6 VALIDATION 6 ENVIRONMENTAL CERTIFICATION A qualified professional shall undertake the remediation supervision and validation sampling All earthworks in areas of identified contamination must be supervised to ensure appropriates controls are in place All soil analysis shall be reported in the form of a Site Remediation and Validation Report (SRVR) for the site to be reported in accordance with the relevant NSW EPA guidelines and AS448 Sufficient validation works should be conducted so that the validation report will be able to conclude that the remediated site will meet the NSW EPA standards and will be suitable for use as a childcare centre 6 VALIDATION SAMPLING REGIME Site validation predominantly focuses on the visual witnessing of the isolation of existing site soils as no site soil is to remain accessible at the conclusion of works Validation sampling is required on imported materials Analysis must include heavy metals, TRH, BTEX, OCP, PCB and PAH The validation of imported materials must also confirm that no bonded ACM or other visible contaminants are present 6 Imported materials Any materials to be used for engineered backfilling should ideally be sourced from certified Virgin Excavated Natural Material (VENM) Other imported materials may also include Excavated Natural Material (ENM) as defined by the NSW EPA in the excavated natural material order 4, provided the ENM is also aesthetically acceptable A qualified environmental consultant is to inspect the source site and confirm that the site history indicates that the site is uncontaminated, and can visually identify the source of materials proposed for importation This must include a documented site inspection, additional sampling confirmation, and a review of any available reports Imported material certified as VENM or ENM must be supported by the appropriate certification documents as well as the results from laboratory analysis conducted on the material Analysis must at a minimum include: o o o o TRH BTEX; PAH; OCP; PCB; and o Heavy Metals (As, Cd, Cr, Cu, Pb, Hg, Ni, Zn) Analytical results of the imported fill must demonstrate compliance with appropriate guidelines and compliance with the RAC Leichhardt Municipal Council Page of 43

27 An inspection and documentation of each load imported to the site for consistency with source site is required Any analytical results collected to support the assessment of VENM must reflect background concentrations and be indicative of VENM Consideration must be given to the consistency of results and published background levels This must be undertaken by a suitably qualified environmental professional and confirmed by the validation consultant Details of the validation of imported backfill materials must be presented in the validation report prepared by the validation consultant Imported horticultural soils (ie turf and garden soils), must also be determined fit for purpose by an appropriate qualified horticultural soil scientist and be supported by appropriate laboratory analysis than should include cation exchange capacity, organic matter, nitrogen, phosphorus, major and minor plant nutrients and trace elements Consideration of geophysical factors such as permeability is also necessary 63 WASTE CLASSIFICATION AND DISPOSAL CERTIFICATION No waste classification has been derived from the information completed in the DSI in accordance with the Waste Classification Guidelines Part : Classifying Waste (NSW EPA, 4), however it is expected that the results from soil characterisation will be utilised in supporting the classification assigned prior to disposal The following procedure should be followed to classify the materials intended for off-site disposal: Remedial works generate a stockpile of materials to be removed from the remediation region A qualified environmental consultant must undertake a visual inspection, including an inspection for the absence / presence of asbestos 3 Sampling and analysis is undertaken on a ratio determined by the consultant based on the consistency and quantity of the material being classified 4 The visual and analytical results shall be used to assign a waste classification in accordance with the Waste Classification Guidelines Part : Classifying Waste (NSW EPA 4) The materials must be removed from site to a facility licensed to receive waste of the classification assigned 6 The validation report for the site must review the methodology, classification and disposal receipts to demonstrate that appropriate classification was undertaken 64 SITE REMEDIATION AND VALIDATION REPORT The environmental consultant shall prepare a Site Remediation and Validation Report (SRVR) detailing the methodologies used in the remediation of the site to meet the remediation acceptance criteria prescribed in this RAP (Section 433) following the conclusion of remedial works The SRVR shall include records of the disposal of contaminated soil materials and provide the findings of the validation assessment, a statement that the site meets the NSW EPA guidelines for the current/proposed landuse and provide details of any validation conditions or EMP requirements pertaining to the ongoing use of the site (if any) Leichhardt Municipal Council Page 6 of 43

28 6 ENVIRONMENTAL MANAGEMENT PLAN A qualified professional shall prepare a Environmental Management Plan (EMP) providing information to control and manage site activities during the implementation of the RAP The EMP manages the Client s staff, contractors and public risk associated with the identified contaminants at the site under current landuse practices and throughout the remediation program The EMP is prepared to manage the potential risks to human health and the environment posed by CPAHs currently present in the soil materials on the site The EMP will provide information on procedures required to ensure the protection of staff, contractors and visitors to the site under normal operating conditions and exception circumstances requiring engagement with the contaminated (isolated) materials on site, and to provide clear details of the location of contamination for appropriate management during remediation Leichhardt Municipal Council Page 7 of 43

29 7 SITE ENVIRONMENTAL CONTROLS 7 OVERVIEW The remediation of the site must be carried out in a manner that does not harm or degrade the environment (both on-site and off-site) All people involved in the project must ensure the protection of the environment throughout the duration of the works with special consideration of the following: Work procedures; Control of fugitive emissions; Dust control measures; Erosion, sediment and surface water management; Noise and vibration measures; Equipment cleaning and operation; and Stockpiles 7 WORK PROCEDURES 7 Establishment and Site Preparation Prior to commencement of remediation activities, the remediation contractor shall prepare a site management plan The objectives of the site management plans are: To protect the health of site workers, adjacent landowners and the general public during remediation works; and To ensure workers do not negatively impact on potential environmental receptors and comply with applicable environmental legislations A control strategy is proposed for the management of all possible sources of exposure or dust release on the site It is recommended that remediation activities be co-ordinated amongst other trades to prevent unauthorised persons from being present in the remediation area Conversely, the work of other contractors needs to be scheduled to preclude them working near to, or within the remediation area until validated The following are the major points that need to be considered in the site management plan: Safety of personnel both on and off site Responsibility for the supply and application of isolating materials (eg ropes, barriers, plastic screens, waste containers, warning signs, etc) Limiting access to remediation area Perimeter/security fencing and erosion control Transport facilities Availability of water and drainage Staff amenities and decontamination areas Protection of adjacent residential structures Waste disposal responsibilities and clean-up requirements Notification to, and approval from, regulating authorities where necessary Leichhardt Municipal Council Page 8 of 43