PSI Vs. DSI – Site Investigations Broken Down

When conducting an environmental site assessment, there are various phases our specialists go through to reach conclusions. The first phase of an ESA itself requires a deep research investigation. Today’s article is going to shed some light on some industry terminology – PSI and DSI. Otherwise known as Preliminary Site Investigations and Detailed Site Investigations.

PSI – Preliminary Site Investigations

A PSI is pretty simple because it’s essentially another way of saying Phase I environmental site assessment. A preliminary site investigation can be requested by either planning authorities or the landowners. Before any sort of work can be done on the land, it must be deemed safe to work on as well as be occupied. The first stage of determining this is done through a preliminary site investigation.

An exhaustive research investigation is initiated to determine whether there is any possibility of contamination or if in the past there was anything that could have potentially contaminated the land. Our consultants gain access to a variety of documents including title information, taxation documents, building permits, planning records, topographical maps and even water/fire department information (just to name a few) in order to assess the likelihood of contamination. The surrounding land and properties are also investigated as it’s possible for contaminants to have seeped into the assessed site through surrounding land.

Furthermore, interviews are conducted with past tenants and relevant government/emergency departments to further gauge whether or not any proof of contamination is, or was ever, present on the site. It should be known that no actual testing takes place during a PSI. The final step of a preliminary site investigation is compiling all the information into a report.

If the details of the said report reveal any evidence of potential contamination, whether it’s current or past, then a phase II environmental site assessment is highly recommended – which involves in-depth testing of elements such as soil, water, mould and lead for example. This second phase is used to conclusively establish whether or not there is contamination present.

DSI – Detailed Site Investigations

A detailed site investigation is a phase II environmental site assessment. As the name suggests, there’s a lot more in-depth and, more importantly, hands-on investigation that transpires during a DSI. The goal of a DSI is to determine whether or not there is any actual contamination on the site. A DSI is not a compulsory phase – but instead recommended based on the initial findings of a PSI.

Using the data from the PSI – specific contaminants and elements can be targeted and looked out for. For example, if there is a structure on the land and the PSI revealed that it was built before 1990, then there’s a possibility that asbestos may be present in the building. In this case, our specialists would tailor their investigation and tests towards revealing asbestos contaminants amongst other routine tests.

As we mentioned earlier, contaminants can seep into the land being assessed from surrounding land or properties. The land itself may have a clean and safe history that doesn’t imply any chance of contamination – however, a neighbouring property may not be so clean. Whilst soil and groundwater are usually always tested during a DSI – potential contamination from neighbouring properties may call for more attention and resources to be directed towards these tests.

Detailed site investigations generally take longer than preliminary site investigations as the tests must be conducted in a controlled, laboratory environment so a conclusive result can be reached. The results of a DSI are critical in determining whether or not further action is required in the form of a phase III environmental site assessment. If the results come back positive for contamination, then remediation is required.

Do you require an environmental site assessment in Melbourne?

Alpha Environmental are the ESA experts and will deliver comprehensive and meticulous investigations from the preliminary phase to the detailed phase. The safety of the environment and the people occupying the land is our number one priority, so you can rest assured knowing that we don’t cut corners and will take the necessary time to conduct a full and proper investigation.

If you would like to know more about our services or would like to get in touch with us regarding an environmental investigation of new land – then please don’t hesitate to contact us via our online enquiry form or by calling 1300 039 181.