Definition of a Phase Two Audit
Phase II investigations are intrusive site investigations which involve taking and analysing samples (soil, water, gas if appropriate) from the site to determine the extent of any contamination which may potentially be present. There are three different types of Phase II which can be conducted depending on circumstance, Exploratory, Main and Supplementary.
Exploratory:
The exploratory investigation is used to obtain site information that gives an indication that the conceptual site model designed in the Phase I is generally correct before conducting the main investigation (if required). The exploratory investigation is often focussed on potential areas of contamination highlighted again in the Phase I. The results of the exploratory investigation can be used to review the conceptual site model making it more accurate and representative of the site. The information gained in the exploratory investigation may conclude that no further investigations is required. However, the results may suggested further intrusive works are needed and the information obtained can be used to design a strategy for the main investigation.
Main:
The main investigation involves the collection and analysis of samples to obtain all the information about potential contamination at a site and for the assessment of risk to human health and the wider environment from the contaminants present. It should be less targeted than the exploratory investigation and it should involve characterisation of contamination, geology, hydrogeology and hydrology of the entire site. The outcome of the main investigation should allow for the development of a remediation strategy.
Supplementary:
The supplementary investigation need only be conducted if the main investigation has identified a deficiency of information and it can therefore be used to improve the accuracy of costing remediation. It tends to be a very focussed investigation to provide clearer delineation of a particular area of contamination or address specific technical matters to improve remediation (Phase III).
