Land Contamination: The Assessment Process

Land Contamination

When a site assessment determines that a piece of land has contamination that may potentially harm people or the environment those responsible for the contamination will be required to clean up the land.

The Environmental Protection Authority (EPA) maintains a list of sites with land contamination which it publishes in the NSW Government Gazette and online. When it becomes aware of a potentially contaminated site it may require an environmental assessment to determine the extent of contamination and whether remediation is required. The latest list of contaminated sites notified to the EPA was published on October 5, 2018 and can be accessed here.

The Assessment Process

Site contamination assessment and remediation may need to go through multiple phases to determine the extent of contamination and the potential health and ecological risks. The requirements for site investigations is defined by the National Environment Protection Measure (NEPM).

Broadly, the assessment process has four phases:

1. Phase I – Preliminary Site Investigation
2. Phase II – Detailed Site Investigation
3. Phase III – Remediation Action Plan
4. Phase IV – Validation

Triggers for Contamination Assessment

A Land Contamination Assessment may be triggered for several reasons, however, the recommended process for assessments remains the same. Overall, the purpose of site assessments is to protect people and our environment by making sure land is safe to use.

Here are a few activities that trigger a Land Contamination Assessment:

Planning and Development

A land contamination assessment can be a precondition for development, especially if the site is being used for a sensitive use such as a childcare center.

Due Diligence

Land Contamination Assessment are regularly undertaken for due diligence in real estate acquisitions, sales, leases and financing requirements. Good due diligence advice quantifies any risks that may be presented by a development project.

Environment Protection Authority

In many cases, it is the Environmental Protection Authority that requires a Land Contamination Assessment and clean-up action to fulfill their legislative requirements in protecting health and the environment. The EPA may require action if they are notified that a site is causing contamination off-site, or where the condition of a site is not suitable for its current use. This can include investigation, remediation works, or a statutory environmental audit.

Preliminary Site Assessment

As Land Contamination can be a result of both current and historical activities on the land, and the sites surrounding it. The first stage of assessment usually involves a desktop study to investigate any potential sources of contamination. This phase of Land Contamination Assessment is tagged as ‘Under Assessment’ by the EPA. If there is no suspicion of any sort of contamination, then this status is changed to ‘Regulation under CLM Act not required’ with no further investigation required. If potential contamination is identified, then further investigation is needed which involves collecting and testing samples from the site.

Land Contamination

What happens if contamination is identified?

Investigation and evaluation of the samples from the site will help to determine the extent of the site contamination and its potential impact on neighbouring sites, the environment in general, and those who will be using it. It is important to note here that just because a sample may test above the NEPM’s screening levels, this does not automatically mean clean-up is necessary. What it does mean is that further investigation is required and a risk assessment is required. When a site is determined to be contaminated, the EPA puts it under the status of ‘Regulation being determined’.

As stated in the NEPM, inappropriate use of investigation levels as default remediation criteria may result in unnecessary remediation adding to development costs and result in unnecessary disturbances to the site, and potentially waste valuable landfill space. If your site shows up on the EPA’s list of contaminated land, you need to ensure that the current use of the site is compatible with the site contamination. Secondly, if the site is subject to EPA regulation, you must comply with the regulatory requirements, which includes notifying other parties who may be affected.

For advice on removing contaminated land from the EPA registers, you should contact Geo-Logix’s team of accredited land contamination professionals.


If a contaminated land assessment determines that remediation is required, a risk-based approach is utilized to make the land suitable for its proposed use. This will rely on the contaminant source-pathway-receptor model developed as part of the Detailed Site Investigation. The extent of remediation will be dependent on site specific issues and priorities related to the levels of contamination and exposure threat to humans and the environment.

The remediation strategy aims to balance environmental, social and economic elements and is defined by the Remediation Action Plan (RAP). The RAP also sets out the validation or management requirements post-remediation which helps ensure that all clean-up objectives are met.

Geo-Logix has helped its clients assess and re-mediate hundreds of contaminated sites in and around Australia. We understand the importance of a well-designed site assessment which is critical for quantifying land contamination risks. If environmental site assessment is done right from the outset, you will reduce the risk of unknown finds enabling costs savings and on-time developments. Geo-Logix offers a high level of technical expertise which is backed by significant industry experience. We possess a sound understanding of all legislative requirements so you can ensure you balance your project objectives with compliance requirements. Contact us for further information and advice on Land Contamination Assessments and Remediation.


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