Detailed Site Investigation (DSI)

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A Detailed Site Investigation (DSI) is usually the next step after a PSI has found that there is a risk of soil contamination being present on a site. The nature of the possible contaminants determines the sampling methodology and design for the investigation. Momentum Environmental Ltd owns an XRF analyser (X-Ray Fluorescence) which enables real-time results of heavy metal contamination in soils. This reduces the need for additional subsequent site visits for delineation where lead and arsenic are the main contaminants. Depending on the site, samples can be taken by hand using specialised equipment or be assisted using an excavator. Samples are transported to IANZ accredited laboratories for testing. 

Depending on the site uses, the most commonly found contaminants of concern include but are not limited to, heavy metals, pesticides, hydrocarbons or asbestos. These all have differing risks to humans and ecological receptors, differing standards and regulatory status,  and differing remediation options.  Momentum staff are experienced in understanding and applying these differences to your specific project. 

Once the results have been received, we analyse them and compare them to national soil contaminant standards or site specific Tier 2 assessments to characterise the site for potential human health and environmental risks. We are also experienced in the use of bioavailability assessments to derive site specific Tier 2 guidelines.

The Detailed Site Investigation is summarised in a concise, easy to read and understand report which meets national guidelines and clearly outlines the approximate quantity and extent of any contamination identified by the work undertaken. It also outlines options for next steps, which could include further sampling to delineate the full extent of a problem, or to address any uncertainties or gaps.  When sufficient information is gathered, the DSI will recommend solutions which are then reported in detail in a Remediation Action Plan (RAP) or an Ongoing Site Management Plan (OSMP). The DSI report could also show that contaminant levels are below human health and environmental guideline values and that no further action is required.