Environmental Audit Report for Shell of 38 McMinn Street Darwin - Aug 2014

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Shell Company Australia
Environmental Audit Report
38 McMinn Street, Darwin, NT
August 2014
Statement of Environmental Audit
Zone A
This Statement provides a summary of the findings of an Environmental Audit of Zone A of the property located at 38 McMinn Street, Darwin, Northern Territory in accordance with Section
47d of the Waste Management and Pollution Control Act (NT). The site is defined on Figure 1 in
Statement - Attachment A.
Name of Auditor Dr Peter Nadebaum
Term of appointment of Auditor 16 May 1990 to 25 September 2015
Date Audit requested 11 June 2010
Owners of the site Shell Company of Australia Limited
Person requesting a Certificate Peter Oxnam of Shell Company of Australia Limited
Planning Authority Development Consent Authority
Title Information Lot 5649, Town of Darwin
Area of the Site 23329 m²
Zoning Central Business under the Northern Territory Planning
Address of the Site McMinn Street, Darwin, Northern Territory
Current Occupier Unoccupied
Site Assessor URS Australia Pty Ltd (URS)
Audit Completion Date 4 August 2014
The audit has had regard to, amongst other things:
 The Waste Management and Pollution Control Act NT 1998.
 The National Environmental Protection Measure for Assessment of Site Contamination
1999 (NEPM, 1999).
 The NT Water Act 1992.
 Advice provided by the Northern Territory Environment Heritage & Arts Division, Department of Natural Resources Environment & the Arts (EHA/DNRETA).
 The general principles for undertaking audits, as outlined by Part IXD of the Victorian
Environment Protection Act, 1970, and the associated policies and guidelines.
Summary of findings
The site was held as Crown land and unoccupied in its natural state until Shell purchased the site circa 1930 and commenced operation as the Shell Terminal in 1937. The site was established for bulk storage and handling of hydrocarbon products. Remediation of the Site has been undertaken to the extent practicable and to make the Site suitable for future development. The development and ongoing use of the Site is subject to certain conditions and the Site Contamination Management Plan (SMP) and Groundwater Quality Management Plan (GQMP) attached to this Statement of Environmental Audit.
The following information is relevant regarding the condition of the Site:
 All on site infrastructure potentially containing hydrocarbons including ASTs, USTs, loading gantries, valve exchanges and associated product delivery lines were decommissioned and removed from site in 2005/2006.
 Large portions of hydrocarbon impacted unconsolidated material in the lower site area were excavated (in Areas 2 and 3). Land farming of hydrocarbon contaminated soil was carried out to reduce the mass of hydrocarbon contamination in the impacted unconsolidated material through the central portion of the Site (Areas 2 and 3).
 During the Site works undertaken in 2011, fragments of suspected asbestos containing material were observed and in Area 1. This material was removed and validated. Visual inspection for ACM was undertaken across other areas of the site at the time of site surface vegetation removal and observation, and there was no evidence of fragments of asbestos containing material remaining at the site.
 Soil hydrocarbon impacts remain at the top of and within the bedrock in areas closely associated with former infrastructure across the Site. The risk posed by this residual contamination has been assessed, and it is concluded that the site is not suitable for unrestricted sensitive use, and restrictions on allowable building types have been defined in the SMP.
 The site has been divided into five (5) development zones (Zones A to E) that correspond to certain types of development that are acceptable in view of the remaining contamination. The zones are shown in Figure 1 of Statement Attachment A. It is noted:
– The restrictions placed on development in each of the zones are precautionary, and it is possible that other development scenarios or land uses may be allowable either through the use of engineering controls, or if further more intensive sampling is undertaken that confirms that the residual contamination does not pose an unacceptable risk to the proposed land use. It is noted that natural degradation of the residual hydrocarbon contamination continues to occur, and it is possible that in the future the residual concentrations will not pose a risk to more sensitive uses.
– If the use of engineering controls is proposed to reduce risks and allow other land uses, the proposed controls should be reviewed by an environmental auditor.
– If further soil, soil vapour or groundwater sampling is undertaken to define the residual contamination, the results should be compared to the criteria listed in this report, or other risk-based criteria developed by an appropriately experienced and qualified specialist in risk assessment, and the conclusions reviewed and confirmed by an environmental auditor.
 With respect to below ground works, the assessment has concluded that the residual contamination does not pose an unacceptable risk to persons working above bedrock level. It is noted:
– On a precautionary basis, the SMP outlines appropriate management controls that should be implemented, and appropriate occupational health and safety practices that should be followed. This includes appropriate personal protective equipment for workers engaged in excavation or entering confined spaces, and consideration of the need for protection of the public and environment from possible dust or vapour emissions.
– The SMP requires that, if works are proposed to be undertaken within bedrock, consideration be given to the engagement of an appropriately qualified and experienced environmental consultant to assess potential for contamination within bedrock fractures and zones of weathering.
 Hydrocarbon odours may be observed during excavations or construction in parts of the site previously impacted when the soil is disturbed (such as in the north-eastern corner of the site); however, it is expected that odorous material will be minor, limited in extent, and the odours will be transitory.
 This report included an assessment for the potential for UXO which found no evidence that explosive ordnance had impacted the site, and that the risk rating for the site was low, refer to Section 6.5.4. The work undertaken to assess contamination has included field surveys and extensive intrusive environmental investigations during 2006, 2008 and
2011, including broad scale excavation over areas of unconsolidated material and outcropping bedrock. This work did not identify material that would suggest that impact from EO or UXO is present.
 There are four plumes of dissolved phase groundwater contamination beneath the site, three of which overlap in the northern section of the site (Area 2).
 The TDS of the groundwater is low (