Site Contamination Assessments

Alpha Environmental Pty Ltd maintains a practical and cost effective approach to the assessment and management of contaminated land to meet the varied needs of land/building owners and occupiers, prospective purchasers, developers, construction companies and petroleum distributors.

The services provided by Alpha Environmental in relation to site contamination will vary depending upon the nature of the site and its current and/or proposed future use. Details of these services are as follows:

Environmental Audits

Pursuant to the Victorian Environmental Act 1970 and the Planning and Environment Act 1987, a site will require a Certificate or Statement of Environmental Audit when/if:

• an amendment to a planning scheme is required for the re-zoning of a site to a more sensitive land use.
• if the owner/occupier requests a site to be removed from the EPA's register of confirmed contaminated sites.
• the EPA requests the audit in the context of a clean-up notice or license condition.

A Certificate or Statement of Environmental Audit may only be issued by an EPA appointed Environmental Auditor. Prior to the issue of the Certificate or Statement of Environmental Audit, a detailed Environmental Site Assessment is typically required.

Environmental Site Assessment

A Environmental Site Assessment involves a detailed site contamination assessment through the performance of a site history review, site inspections, sampling of soil to the density recommended by Australian Standard AS4482 Guide to the sampling and investigation of potentially contaminated soil and subsequent analysis for a wide range of potential soil contaminants. Depending on the location and nature of the site, an investigation of groundwater contamination may also be required.

The joint Australian and New Zealand Environment and Conservation Council/National Health and Medical Research Council 1992 publication Australian and New Zealand Guidelines for the Assessment and Management of Contaminated Sites is used as a primary reference for determining whether contamination is present on site, with various state-based, national or international guidelines also being utilised in the interpretation of results.

Once the presence and full extent of any site contamination has been confirmed, recommendations are provided as to the appropriate course of action to be taken. These recommendations will vary depending upon the level of contamination and proposed use of the site.

Preliminary Site Assessments

A Preliminary Site Assessment is aimed at providing a cost effective investigation into the potential for contamination to be present on a site. Such an assessment is of benefit to both prospective purchasers and/or developers in order to provide an indication of the suitability of a site for a proposed future use.

The preliminary contamination assessment is achieved through a site history review, site inspection and limited soil sampling and analysis and, if required, groundwater investigations.

Depending upon the results of the preliminary contamination assessment and the proposed future use of the site, there may be a requirement for further, more detailed investigations to be undertaken.

Underground Fuel Storage Tanks

The assessment of potential contamination from underground fuel storage tanks may form part of a Preliminary or Detailed Environmental Site Assessment or may be performed independently.

The assessment of underground fuel storage tanks may include:

• an assessment of the physical condition of tanks through vessel pressurisation.
• the excavation of auger/bore holes in the vicinity of the tanks, bowsers and associated pipes, the collection of soil sample and subsequent analysis for chemical contaminants.
• the installation of groundwater monitoring wells, the collection of water samples and analysis for chemical contaminants.

The assessment of underground fuel storage tanks is performed in accordance with the guidelines provided the NSW EPA publication Contaminated Sites: Guidelines for Assessing Service Station Sites and various publications of the Australian Institute of Petroleum.

Recommendations are also provided to assist is compliance with the Victorian EPA Publication 888.

Site History Reviews

A site history review provides information relating to the current and previous site owners/occupiers in order to determine activities which may have resulted in site contamination, the likely type of contaminants to be found onsite, and possible locations to be targeted during site investigation works.

Information for site history reviews is compiled from a wide range of sources including interviews with previous occupiers or employees, property title searches, council records, aerial photographs and historical records from Sands and McDougall Directories.

An assessment of the existing conditions of the site is also performed, which focuses on current site activities, the presence of fuel storage tanks, chemical stores, surface staining, poor or sparsely vegetated areas, odours and an assessment of site drainage, topography, and adjacent land uses.

Following collation of all relevant information, an indication of the potential for site contamination to exist can be provided, and the extent of any soil/groundwater sampling required.

Groundwater Assessments

The installation of groundwater monitoring wells and collection/analysis of groundwater samples may be undertaken as part of a Phase 2 Site Contamination Assessment, prior to the issue of Certificate or Statement of Environmental Audit or as a means of determining the beneficial uses of groundwater.

AS/NZS 5667.11-1998 Water Quality - Sampling Part 11: Guidance on sampling of groundwaters and the 1992 ANZECC publication Australian Water Quality Guidelines for Fresh and Marine Waters are used as the primary reference documents in the sampling/analysis of groundwater and interpretation of results.

Characterisation of Soils Prior to Off-Site Disposal

Where soil excavation and off-site disposal is required during site development works, characterisation of soil in performed in order to determine the appropriate classification in accordance with the Environment Protection (Prescribed Waste) Regulations.

Depending upon the nature of the site and quantities of soil to be disposed of, the characterisation of the soil may be performed in situ or following excavation and stockpiling.

Validation Testing

Following from the excavation of contaminated soil or underground storage tanks, validation testing of the walls and/or base of the excavations is performed to ensure that the remediation works have been performed to a satisfactory standard.