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The importance of a desktop study in environmental assessments

The Preliminary Site Investigation (PSI) includes a desktop study to understand the current and historical land uses of a site and its surroundings. It is the first stage of a contaminated site assessment and an essential step in assessing the environmental risks associated with potential contamination.

Historical research is a key component of a site assessment desktop study because it helps to pinpoint the source of any contamination found on a site. Without a clear understanding of past operations on or near the site, laboratory testing and exposure models can, at best, only suggest possible causation of contamination and cannot identify waste generators, owners, occupiers, transporters or other responsible parties to contamination.

Information Sources for a Desktop Study

A desktop study is a forensic approach which involves analysing historical documents to provide insight on past site owners, users and uses. Sources of information include:

  • Current and historical aerial and ground photos;
  • Historical titles back to original deeds;
  • Environmental licenses, trade waste permits and other council and government records;
  • Maps and reports;
  • Local knowledge of residents and past owners/occupiers;
  • Historical societies and libraries;
  • Site plans showing sewer and underground services;
  • Past Development Applications;
  • Groundwater bore records; and
  • Registers of contaminated land.

One Piece of the Puzzle

Relevant site information is compiled to provide a chronological list of all land uses and the parties that have owned or used the site (and may be responsible for any identified contamination). When completing the PSI this information is then assessed in light of the site’s physical characteristics and proposed use. This is where a site inspection is critical to validate historical and anecdotal information and identify evidence of potential contamination such as unusual odours, distressed vegetation, soil and pavement staining or discolourations, and sheens on water surfaces.

Due Diligence

An appropriate desktop study will enable a consultant to identify potential contamination on a site, including the potentially affected media (soil, ground/surface water, or indoor/outdoor air) and the potential areas of contamination. Such information can be invaluable due diligence prior to property acquisition and can be used to estimate or allocate clean-up costs. Likewise, a desktop study can help to sort out the parties responsible for contamination and support decisions to claim or defend against liability.

Need More Information?

If you would like advice on your site or a quote for a Preliminary Site Investigation (also called a Phase I Environmental Site Assessment) please call 02 9979 1722 or contact Ben Pearce at