Sampling is essential to identify whether the site has been impacted by contamination due to past or current land use activities. Even if a site appears clean visually, contaminants such as heavy metals, hydrocarbons, or asbestos can be present below the surface and may pose a risk to human health or the environment. Sampling provides evidence-based data to determine if the site is suitable for its current or proposed use.

In some cases, a Preliminary Site Investigation (PSI) may be completed without sampling if historical records, aerial imagery, and a site inspection clearly show that the site has not been used for any potentially contaminating activities. However, if there are data gaps, conflicting information, or evidence of past land uses that could have caused contamination, sampling is usually required. The decision is guided by both regulatory standards and the professional judgment of the environmental consultant to ensure the assessment is accurate and defensible.

The number of required samples depends on several factors, including the size of the site, its historical and current land use, the location of any areas of environmental concern, and regulatory guidance such as the NEPM 1999 (as amended 2013). In addition to following these standards, the professional judgment of the environmental investigator plays a key role in determining appropriate sample numbers and locations. This judgment is based on experience, site observations, and known or suspected contamination risks, helping to ensure that the sampling strategy is both efficient and effective.

If contamination is detected above guideline levels, we may need to proceed to a Detailed Site Investigation (DSI). This will involve more targeted sampling to define the extent, nature, and severity of the contamination. Based on the DSI results, a Remedial Action Plan (RAP) may be required to address the issue.

A PSI typically takes 1–3 weeks depending on site access and sampling requirements. A DSI may take longer due to more extensive sampling and analysis. We’ll provide a timeline as part of our proposal and keep you updated throughout the process.

Acid sulphate reports are generally a requirement specified by council in the process of applying to proceed with a development. Councils typically require this in areas that are highlighted in the acid sulphate soils risk maps, and are often confined to estuarine, coastal, and low-lying areas. If your development falls within these areas, you will possibly be required to test for the presence of acid sulphate soils