Preliminary Site Investigation

Summary

A Preliminary Site Investigation (PSI) is the first stage of contaminated land assessment.

Its purpose is to understand the history and environmental setting of a site, identify activities that may have caused contamination and determine whether further investigation is required.

A PSI is commonly undertaken for development applications, rezoning, subdivision, property due diligence and sites with a potentially contaminating history.

Definition

A Preliminary Site Investigation is primarily a desktop and site-based assessment of potential land contamination.

It typically considers:

• historical and current land uses;

• previous buildings and infrastructure;

• potentially contaminating activities;

• imported fill and earthworks;

• regulatory and environmental records;

• surrounding land uses;

• geology, groundwater and surface water conditions; and

• observations made during a site inspection.

This information is used to identify Areas of Environmental Concern (AECs), Contaminants of Potential Concern (CoPCs) and develop a preliminary Conceptual Site Model (CSM).

What Is the Purpose of a PSI?

The main purpose of a PSI is to determine whether contamination is known or potentially present and whether it could be relevant to the current or proposed use of the site.

A PSI may conclude that:

• no further contaminated land investigation is warranted;

• additional targeted investigation is required; or

• another form of environmental assessment or management is appropriate.

A PSI does not automatically mean that a Detailed Site Investigation will be required.

What Does a PSI Typically Include?

A PSI commonly includes:

• review of historical aerial photographs and land-use information;

• review of relevant environmental and regulatory databases;

• review of previous environmental reports where available;

• site inspection;

• identification of potential contamination sources;

• identification of AECs and CoPCs;

• development of a preliminary CSM; and

• conclusions and recommendations regarding further investigation.

Limited sampling may sometimes be undertaken where it is appropriate to the investigation objectives, although more extensive intrusive investigation is generally undertaken as part of a Detailed Site Investigation (DSI).

PSI vs DSI

A PSI and DSI serve different purposes.

A PSI asks:

Could contamination reasonably be present, and does it require further investigation?

A DSI generally asks:

Is contamination present and, if so, what is its nature, extent and significance?

A DSI typically involves intrusive investigation such as soil, groundwater or soil vapour sampling.

When Is a PSI Commonly Used?

A PSI may be undertaken for:

• Development Applications;

• rezoning or planning proposals;

• subdivision;

• proposed changes to more sensitive land uses;

• commercial or industrial property transactions;

• pre-purchase environmental due diligence; or

• sites with historical industrial, agricultural, fuel storage, waste disposal or other potentially contaminating activities.

The need for a PSI depends on the site history, proposed use and requirements of the relevant consent authority.

Related Terms

• Area of Environmental Concern (AEC)

• Contaminant of Potential Concern (CoPC)

• Conceptual Site Model (CSM)

• Detailed Site Investigation (DSI)

• Contaminated Land

• Environmental Due Diligence

• Remediation Action Plan (RAP)

Need a Preliminary Site Investigation?

For information about engaging Confluence Environmental for a PSI, visit our Preliminary Site Investigation services page.