Contaminated Land Consulting

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One particular niche of environmental consulting is Contaminated Land Management. A specialised contaminated land management consultant is required when property is rezoned from a commercial zone to a residential zone, or if a request has been made to remove land from the Contaminated Sites Register.

Contaminated Land Consultants are often required required by property developers when they are buying (or selling) land suitable for commercial or residential development.

For property owners and land developers, the most important thing to understand about purchasing land that is potentially contaminated is the risks involved. Frtom a legal standpoint, land owners are responsible for the remediation of contamination on their land. For this reason, it’s essential to investigate a property’s contamination status prior to purchase, to avoid purchasing expensive environmental liabilities along with the land.

The primary service an environmental consultant specialising in contaminated land provides is site contamination reports. These reports determine the risk of or the extent of contamination on a site. This is often referred to as a Preliminary Site Investigation (PSI), or a Phase 1 Environmental Site Assessment.

A PSI will identify the likelihood of, plus and any potential sources of contamination, the location of potential contamination, any potentially affected media (soil, groundwater, etc) and any human and ecological receptors. A full Preliminary Site Investigation includes the following:

  1. Identification and description of the site,
  2. An overview of the site history (zoning, occupants, historical uses, aerial photos, ownership, processes, interviews, etc);
  3. An analysis of the environmental setting (geology, hydrogeology, topography, etc);
  4. A site reconnaissance visit to visually inspect the site (and surrounds) for contamination;
  5. An initial conceptual site model; and
  6. Optionally (if warrented) limited contaminant sampling and analysis at areas of possible concern.

A PSI may conclude that there is a significant potential for contamination (in which case further studies should be conducted). However, if a thorough preliminary investigation shows a history of non-contaminating activities and there is no other evidence or suspicion of contamination, further investigation is not required. On the other hand, if a Preliminary Site Investigation (PSI) identifies a likelihood of contamination and the available information is insufficient to enable site management strategies to be devised, a Detailed Site Investigation, or DSI, may need to be conducted. This is sometimes referred to as a Phase 2 Environmental Site Assessment, which is an investigation stage.

A Phase 2 ESA sets out to delineate the vertical and lateral extent of site contamination – usually with the site’s proposed land use in mind; or to inform about any appropriate site remediation or management options. At this stage soil is always tested and groundwater and/or surface water is tested where the past use of the site means there is a risk of contamination; or if the soil is contaminated with compounds that can contaminate groundwater, or if a surrounding site is known to be, or is potentially contaminated, and there is a risk of the contamination migrating to your site. Where a properly planned and executed DSI demonstrates that the site is not contaminated, no further works are required and a report authenticating the sites clean status is issued.

On the other hand, if it demonstrates that the site is contaminated; further investigation to inform decontamination requirements or to clarify potential human health risks may be required, depending on the proposed land use of the site.

Environmental auditing of a site can be a protracted exercise involving soil and groundwater assessment, human health risk assessment, determination of “clean up to the extent practicable” of contaminated groundwater, and off-site testing. A contaminated land audit may identify environmental contamination issues that require rectification or management and this can be costly.

In some circumstances a complete and total clean up of contaminated land is not required. A contaminated land audit may be completed on a site that contains some ‘residual contamination’, and the auditor may issue a ‘Statement of Environmental Audit’ so that development on this land can then proceed, as long as the contamination is in keeping with acceptable land use.

Where a Statement of Environmental Audit is issued, it may contain certain conditions, particularly if the site has been found to be a source site of contamination. Sites with a completed Statement of Environmental Audit may require an ongoing Groundwater Quality Management Plan, Soil Contamination Management Plan, or Further soil/health-risk assessment requirements.