Contaminated land Consultants are a branch of environmental consultants that deal with compliance and audit issues where audits are required if a property is being rezoned to a more “sensitive” land use, for example, from commercial to residential, or if a request has been made to remove land from the Contaminated Sites Register and their services are often used by property developers when buying (or selling) land suitable for commercial or residential development.
Preliminary Site Investigation
The first service a contaminated land consultant will provide is to determining the risk of site contamination which is referred to as a Preliminary Site Investigation (PSI), or a Phase 1 Environmental Site Assessment report. The PSI should be sufficient to identify potential types/sources of contamination, locations of potential contamination, human and ecological receptors and potentially affected media (soil, groundwater, etc).
A thorough Preliminary Site Investigation (PSI) will involve the following:
identification and description of the site,
the site history (zoning, occupants, historical uses, aerial photos, ownership, processes, interviews, etc);
the environmental setting (geology, hydrogeology, topography, etc);
a site reconnaissance visit to visually inspect the site (and surrounds) for contamination;
an initial conceptual site model; and
(optionally) limited contaminant sampling and analysis at areas of potential environmental 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. However, if a Preliminary Site Investigation (PSI) identifies a risk 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.
Detailed Site Investigation
The DSI is the site sampling, or Phase 2 investigation stage. It 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 upon appropriate site remediation or management strategies.
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; 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, then no further works are required. If it demonstrates that the site is contaminated, further investigation to inform decontamination requirements or to clarify potential human health risks may be required.