The purpose of a Phase 1 Land Contamination Assessment or Preliminary Risk Assessment (PRA) is to establish the previous uses of the land under consideration or land nearby or adjacent to it, and to identify potential sources of contamination, receptors and pathways. It is important to identify all past uses of the site, and adjacent or nearby sites, since pollutants have the potential to travel away from the source, depending on the geology, groundwater and surface water of the area.
The Phase 1 Land Contamination Assessment should contain an outline conceptual site model based on the findings of a desktop study and site walkover that characterises all actual or potential pollutant linkages. This will then form the basis of any subsequent work undertaken such as intrusive investigations, risk assessment etc. and set out any necessary remediation works required as part of a subsequent Phase II assessment. Alternatively the findings will rule out the need for further work at an early stage.
A Phase 2 assessment consists of an Intrusive site investigation with quantitative risk assessment. Depending on the outcome of this assessment a subsequent remediation strategy and verification report will then also be required. A Phase 2 assessment is only required if the need for one has been identified in the initial Land Contamination Assessment or to accord with any conditions the Local Planning Authority have attached to the planning approval.
The Phase 2 report should be submitted to and approved in writing by the LPA and implemented prior to development commencing. However although it is the final document and implementation of any required remediation works that are likely to be required to fully discharge relevant conditions, a phased approach is recommended.