Introduction
Preliminary Site Investigations (PSIs) are essential for identifying environmental risks early in the development process. One of the key outcomes is detecting soil contamination, which can significantly impact project timelines, approval pathways, and remediation costs.
This article answers five commonly asked questions about common soil contaminants identified during PSIs and how they affect remediation.
What Is a Preliminary Site Investigation (PSI)?
A Preliminary Site Investigation (PSI) is the first step in assessing whether a site is contaminated. It involves reviewing historical land use, conducting site inspections, and identifying potential contamination risks. PSIs are typically required:
- As part of due diligence during property transactions
- For planning approvals and rezoning applications
- Prior to construction or redevelopment
- Under NSW EPA and SEPP 2021 regulatory frameworks
The goal is to determine whether contamination is potentially present and if a Detailed Site Investigation (DSI) is required.
What Are the Most Common Soil Contaminants in Australia?
Several high-risk contaminants are frequently found on commercial, industrial, and even some residential development sites. The most common include:
- Asbestos fragments from old building materials or illegal dumping
- Heavy metals like lead, arsenic, mercury, and cadmium (often from historical industrial or agricultural use)
- Total Petroleum Hydrocarbons (TPH) and Polycyclic Aromatic Hydrocarbons (PAHs) from fuel leaks or old mechanical workshops
- Pesticides and herbicides from past agricultural operations
- Polychlorinated Biphenyls (PCBs) from electrical equipment or transformers
- Per- and polyfluoroalkyl substances (PFAS) from firefighting foam or industrial activities
These contaminants may occur individually or in combination, depending on the site’s land-use history. For more information on Soil & Waste classification, please visit our dedicated page.
