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Contaminated land investigations shouldn’t end after a single test. Between volatile environmental conditions and updated regulations, many things can change over the lifetime of a project.
In Western Australia, understanding your re-testing obligations is an important part of due diligence and risk management. For site owners, developers and managers, knowing when and how to conduct repeat a contaminated site investigation can save costs and prevent delays.
In this article, we explain why re-testing is important, when you should complete it and how West Soil & Water can assist throughout the whole process.
Contaminated sites are dynamic environments. Whether it’s because of environmental events, ongoing remediation or just wear and tear, conditions can change in ways that aren’t immediately visible.
Whilst an initial investigation will offer a baseline for understanding contamination, it’s only after you re-test that the data tells the whole story. Further investigation captures the changes that might be occurring on your site, ensuring that risk assessments remain accurate and protective of human and environmental health. It also verifies the efficacy of your remediation measures and whether they need adjusting.
Without re-testing, developers and landowners can falsely assume their site is safe. Although an initial investigation may suggest that, there can be contaminants that have either persisted or remerged, leading to project delays and regulatory intervention.
Re-testing isn’t just about safety and compliance, it’s also about reducing uncertainty. Projects that overlook repeat investigations can encounter countless delays and budget blowouts that reduce the confidence of investors, regulators and other community stakeholders.
By integrating re-testing into the project timeline, you can ensure that these risks are managed proactively and that all parties can proceed with confidence.
There are several circumstances that might trigger re-testing on a contaminated site:
Completion of Contaminated Land Treatment or Remediation: Verification sampling is often required to demonstrate that clean-up efforts have reduced contamination to acceptable levels.
Changes in Land Use: Different land uses warrant different safety thresholds. Re-testing may be needed if, for example, the site is moving from industrial to residential use.
Discovery of New Information: Further testing is needed if historical records or neighbouring site investigations reveal previously unknown risks.
Environmental and Industrial Events: Flooding, groundwater changes or nearby construction can mobilise contaminants.
Regulatory Requirements: Government agencies may request further sampling before approvals are granted.
If you do need to complete re-testing on your site, it is important that you understand the reason. This will help your formulate an appropriate strategy and inform later efforts to remediate land.
There is no ‘one-size-fits-all’ timeline for re-testing contaminated land. The schedule will depend on the nature of the contamination and other site conditions. For example:
High-Risk Sites: Sites with volatile compounds may require regular testing every few months. Alternatively, you could implement an ongoing monitoring system.
Low-Risk Sites: Locations where contaminants are contained or stable may only require re-testing every few years or in response to specific changes.
Redevelopment Projects: Here, testing is typically tied to project milestones, such as prior to demolition, excavation or construction.
This decision is usually guided by a site-specific risk assessment to ensure that testing frequency aligns with both regulatory expectations and project needs.
At West Soil & Water, our consultants provide clear guidance on re-testing, basing their decisions off site conditions, regulatory guidelines and your project goals. Our environmental assessments include:
Preliminary Site Investigations (PSI): Including reviews of historical records, aerial photography and site activities to identify potential contamination risks. You may also see these referred to as Phase 1 Environmental Site Assessments.
Detailed Site Investigations (DSI): Also known as Phase 2 Environmental Site Assessments, these investigations involve more thorough soil, groundwater and material collection for laboratory analysis.
Depending on the results, we may recommend a targeted remediation strategy. By integrating re-testing into broader contaminated land management, West Soil & Water helps clients meet compliance obligations and maintain project momentum.
Re-testing is a critical safeguard in contaminated land management. To keep risks under control and ensure your project’s compliance, contaminated site investigations should be treated as an ongoing requirement.
When you engage an experienced environmental partner like West Soil & Water for soil testing, you can plan with certainty and avoid costly disruptions. For more information or to discuss your site with a member of our team, please get in touch.