RE: BANKSTOWN BUSINESS ESTATE - Site Remediation Strategy

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1 Gemma Wawn, Leda Holdings Pty Ltd, Level 11, 5 Hunter Street, SYDNEY NSW g.wawn@ledaholdings.com.au 23 June 2015 RE: BANKSTOWN BUSINESS ESTATE - Site Remediation Strategy CES Ref: CES LED-AB Dear Gemma, The purpose of this letter is to provide a summary of the issues relevant to site contamination at the above site, and to outline a strategy for remediation of areas affected by contamination so that the site is suitable for the proposed development. We understand that the proposal is for a major employment generating development and will include a Factory Outlet Centre, Large Format Retail/Leisure and Business Park. The Leda Group is currently preparing a draft Major Development Plan (MDP) for the proposal in accordance with the Airports Act 1996, the Commonwealth Major Development Plan Assessment Guidelines and the Bankstown Airport Master Plan, in association with Bankstown Airports Limited. 1. INTRODUCTION The site covers an area of about 41 ha and is part of the Bankstown Airport landholding. Most of the subject site currently comprises unoccupied land which is surplus to aviation purposes. The only part of the site in active use is the area of the Australian Aviation Museum within the southern part of the site, which includes an asphalt hardstand area, a hangar and associated office and storage buildings, numerous aeroplanes and aircraft parts etc. The rest of the overall site generally consists of a flat grassed surface, devoid of trees or man-made features. Most of the subject site has been subjected to filling in the past, with the principal fill material found to be sandy and clayey soil, but with minor quantities of demolition materials including concrete, bricks, wood, asphalt, road base, aggregate, sandstone and occasionally plastic, metal, tiles etc. The current application seeks approval for the following: CONSULTING EARTH SCIENTISTS Suite 3, Level 1 55 Grandview Street Pymble NSW 2073 Australia T F W

2 Demolition and removal of all remaining existing on-site structures, including the Australian Aviation Museum, which will be relocated to Camden Airport; Bulk earthworks; Land subdivision to create 6 lots, 5 for buildings and 1 for road infrastructure; Construction and use of areas set aside for drainage reserves and to manage overland flow; Construction the primary road access (Lot 1) being one road connecting Tower Road to the west of the site to Milperra Road to the south-east of the site named Spine Road ; Civil works; Landscaping within proposed road corridors; Provision of pedestrian and bicycle access paths and facilities; Building location and envelopes for the construction on the various lots: Strategies for stormwater management, utility services, aviation constraints planning, ground transport and Construction Environmental Management Plan. 2. SITE HISTORY The site history provided in the Stage 2 ESA was based on a review of the report prepared by Godden Mackay Logan (April 2005) Bankstown Airport, Heritage Management Strategy. The Godden Mackay Logan (April 2005) report outlines the history of the entire Bankstown Airport site. It should be noted that the historical operations/activities detailed may have not been specifically undertaken on the site. The site history can be summarised as follows: The Bankstown Airport site was formerly occupied by market gardens, poultry farms and commercial premises (including a service station) located at the corner of Milperra and Billiana Roads; Construction of the Airport commenced in 1940; The Royal Australian Air Force (RAAF) established at the site in late The activities undertaken by the RAAF included airfield and training operations, aircraft assembly and temporary accommodation for RAAF personnel; The Women s Australian Auxiliary Air Force (WAAAF) established on the site in The activities undertaken by the WAAAF included training, administration and accommodation; CES Document No: CES LED-AB Page 2 of 8

3 The US Air Force were accommodated at the site from 1942 to The site was used to as a base for a number of squadrons and accommodated the associated personnel; The Clyde Engineering Co Pty Ltd undertook maintenance, repair and modification of aircraft from 1942; Hawker de Havilland opened a factory in 1942 for the manufacture of aircraft and parts; A Mobile Naval Air Base was commissioned at Bankstown in As part of this commission, hangers, taxiways and associated facilities were constructed; From 1945 to 1950 sections of the site were used to house migrants; and The control of the Bankstown Airport was divested to the Department of Civil Aviation (DCA) in PREVIOUS INVESTIGATIONS The site has been subject to environmental investigations, by Consulting Earth Scientists (CES) and David Lane Associates (DLA). The previous reports are as follows: Stage 2 Environmental Site Assessment: Area 6, Bankstown Airport (Prepared for BAC Devco Pty Ltd). CES Report ID CES BAC-01-F, 21 November 2005; Environmental Management Plan: Construction Phase, Stage 1 South-West Precinct, Bankstown Airport, NSW. CES Report ID CES BAC-10-F, 3 April 2009; Asbestos Contamination Assessment BAC Devco Pty Ltd, Bankstown Airport South West Precinct Stages 1 & 2. David Lane Associates, DL2227, May 2009; Remediation Recommendations: Asbestos Contamination - BAC Devco Pty Ltd, Bankstown Airport South West Precinct Stages 1 & 2. David Lane Associates, DL2227, May 2009; Asbestos Clearance Certification Documentation Bankstown Airport South West Precinct Stage 1. David Lane Associates, DL2227, May 2009; Fill Material Land Use Suitability Assessment Lot 305 DP , 41L Starkie Drive, South West precinct, Bankstown Airport NSW DLA Environmental, for Korda Mentha; DL3301_S001608, May 2014; Fill Material Land Use Suitability Assessment Lot 305 DP , 41L Starkie Drive, South West precinct, Bankstown Airport NSW DLA Environmental, for Korda Mentha; DL3301_S002798, March CES Document No: CES LED-AB Page 3 of 8

4 Note that the first of the previous reports listed above (the Stage 2 ESA by CES of 2005) was not preceded by a Stage 1 or Phase 1 ESA, as it was not considered necessary. Instead an outline of the site s history and general information on the site s condition and physical attributes was included in the Stage 2 ESA, as summarised above insection 2. The 2009 reports by David Lane Associates (DLA) relate specifically to the assessment and partial remediation of asbestos materials within the fill. The two latter reports by DLA refer to sampling and testing of imported stockpiled soil to determine the land use suitability of the material and its potential for re-use on-site. The previous investigations referred to the site in two parts: the Stage 1 area which comprised the north-eastern half of the site and the Stage 2 area which is essentially the southern half and includes the Aviation Museum. These are shown in Figure 1 attached. 4. SUMMARY OF CONTAMINATION & PREVIOUS REMEDIATION The contamination status of the soils and fill materials on the site can be summarised as follows: Fill depths are mostly less than 2m, but in some cases fill depths over 3m were recorded; generally fill depths are greatest in the eastern part; Fill materials comprise mostly sandy and clayey soil, but with minor quantities of demolition materials including concrete, bricks, wood, asphalt, road base, aggregate, sandstone and occasionally plastic, metal, tiles etc; It appears as though some fill has been introduced to the northern or Stage 1 area since the original investigation by CES in 2005; The initial Site Assessment by CES in 2005 noted that the concentrations of all potential contaminants tested in soil and fill samples (including metals, petroleum hydrocarbons, BTEX, PAHs, organochlorines, organophosphates, phenols and asbestos) on the site were below the appropriate soil investigation levels for commercial and industrial land uses; The CES 2005 report concluded that the site is suitable for commercial/industrial redevelopment; Additional investigations by CES in 2008 during earthworks identified the presence of some asbestos-cement pieces in some areas of the fill; subsequent investigations over the whole site area by DLA in 2009 found asbestos fragments in 3 of 40 test pits in the Stage 1 area (and as visible surface fragments in much of the strip adjoining the north-eastern boundary of Stage 1). DLA also found asbestos fragments in several test pits within the Australian Aviation Museum area (which falls within the Stage 2 area); CES Document No: CES LED-AB Page 4 of 8

5 Some remediation of asbestos was then carried out in the Stage 1 area in accordance with the DLA Remediation Recommendations (also in May 2009) in that the areas of the 3 test pits were excavated and the fill materials hen picked to remove the fragments of asbestos material. These materials and each of the pits were then given a visual clearance certification that no asbestos fragments remained present; also a bulk soil sample was collected from each and subjected to analysis for asbestos fibres (these all showed no asbestos fibre presence); The DLA Asbestos Clearance report notes that while the remedial works were specifically targeted at where the asbestos contamination had previously been reported, it was also possible (even likely) that asbestos fragments are still present in other areas of Stage 1, though not observed in the other test pits dug. For this reason, DLA included an Unexpected Finds Protocol in their Asbestos Clearance report, to be applied in any future earthworks or construction activities at the site; Note that no remediation works appear to have been undertaken in the Stage 2 or Australian Aviation Museum area (where asbestos was also found by DLA); Although asbestos-cement fragments have been found and maybestill present in some areas, particularly in the Stage 2 area, it is important to note that none of the laboratory analyses of fill samples (by either CES or DLA) showed the presence of asbestos fibres; It will also be necessary to closely inspect the surface in the area of the drainage reserve along the northern boundaries of the Stage 1 area (new Lot 6 on the attached plan) for the presence of asbestos-fibre materials; Localised staining of the surface was noted in parts of the Aviation Museum area, probably a result of spillage of oil and fuels, and should be assessed to determine whether the levels of contamination exceed the appropriate site criteria; The recent (2015) work by DLA Environmental indicated that the large area of stockpiled imported soil, which is immediately to the east of the Aviation Museum, is suitable for re-use on site as part of the development as it was found to satisfy the most sensitive criteria for residential land use and therefore also satisfies the less stringent criteria applying to commercial/industrial land use. Some of the test pit samples of stockpiled material did show the presence of asbestos-cement pieces but the quantification criteria is satisfied for residential or commercial land use and none was found on the surface. It is considered that there have been adequate environmental investigations and soil and fill assessment of the subject site to properly characterise the sub-surface conditions for the proposed redevelopment. CES Document No: CES LED-AB Page 5 of 8

6 5. REMEDIATION STRATEGY The strategy for dealing with the asbestos affected soils which is outlined below refers to the overall site area in terms of Stage1 and Stage 2, as per the previous reports, and as shown in Figure 1. Stage 1 Area As discussed above, this northern part of the site (shown in the plan below) has been partially remediated. However as identified in the DLA Asbestos Clearance report, there is an on-going requirement for supervision and careful assessment of fill materials in any cases where excavation is planned or where fill from below the surface is exposed. This should include visual inspections and sampling and analysis for asbestos where appropriate. All persons or contractors working on the site must be made aware of this need, and the requirements for supervision and assessment must be a part of site inductions for all relevant personnel. Stage 2 Area The protocol for remediation in this area is to be partly in accordance with the DLA report entitled Remediation Recommendations Asbestos Contamination, though the need for further specific remedial excavations no longer exists. The Stage 2 area can be considered in two parts firstly the area outside the boundaries of the Aviation Museum, and secondly the area of the Aviation Museum itself (including the aircraft parking area). There is also 2ha area adjoining Tower Road that has not been tested to date. This area is show in the plan below. It is intended that this parcel of land will be tested upon approval of the proposed development. CES Document No: CES LED-AB Page 6 of 8

7 The Subject Site Stage 1 and Stage 2 and areas where further testing required. A. Area Outside Aviation Museum Surface removal of asbestos-containing materials (by hen-picking ) of the areas indicated on the DLA Asbestos Contamination Assessment report Figure 3.2, where such materials have been identified as being present, and also along the drainage reserve adjoining the northern boundaries of the Stage 1 area (new Lot 6). This should be undertaken by a contractor holding the appropriate asbestos removal license, and supervised by a consultant familiar with the site and investigation findings. B. Area Within the Aviation Museum Surface removal ( hen-picking ) of visible asbestos fragments in the areas identified in Figure 3.3 of the DLA Asbestos Contamination Assessment report, in the vicinity of test pits TP 80, 83 and 85 as well as throughout the northern part of the Aviation Museum unsealed aircraft parking area (as indicated in Figure 3.3 by the test pits which contained asbestos fragments). It appears as though no specific asbestos remediation excavations (as were carried out in the Stage 1 area in 2009) have been carried out in the Aviation Museum area. CES Document No: CES LED-AB Page 7 of 8

8 Remediation of this type is now not considered necessary in the affected part of the Aviation Museum area, as this part of the site will be entirely below the sealed car park to the north of the factory outlet centre (refer to the Bankstown Business Estate Master Plan). Some inspections and possibly sampling and analysis of the minor hydrocarbon staining in the northern and eastern aircraft parking areas should be undertaken (preferably after removal of the aircraft) to determine whether these areas exceed site criteria and require any soil removal or remedial action. 6. CONCLUSION In terms of satisfying State Environmental Planning Policy 55 (SEPP 55) Remediation of Land (1988), we consider that no specific site remediation program is required for the site. For this reason, we believe a Remedial Action Plan (RAP) is not required. Instead, supervision with adequate testing and classification of the fill materials should be undertaken at the time of excavation and any off-site disposal, in accordance with the strategy outlined above. For and on behalf of Consulting Earth Scientists Pty Ltd. Yours sincerely, David Johnson, Principal Environmental Scientist CES Document No: CES LED-AB Page 8 of 8