Phase 1 - Preliminary Risk Assessment (PRA) - Desk Study
A Phase 1 PRA, commonly referred to as a desk study is the first step in a contaminated land site assessment, which generally involves the following aspects:-
- Define project objectives
- Site reconnaissance and visual inspection (site setting, location, surroundings, topography etc.)
- Desk study including a review of historical and geological maps and local environmental information (archaeology, ecology etc.)
- Qualitative contamination assessment (source-pathway-receptor linkages), areas of potential concern (AoPC) and the construction of a preliminary conceptual site model (CSM)
- Liaison with Environment Agency and local authority
- Production of a Phase 1 PRA Report
The outcome of the Phase 1 PRA is the production of a preliminary conceptual site model (CSM), which is a qualitative assessment of risks that may arise as a result of the impact of potential sources of contamination via plausible pathways upon sensitive receptors given the intended end-use scenario of the site in question.
Risk is defined as a combination of the probability, or frequency, of occurrence of a defined hazard and the magnitude of the consequences of the occurrence. In the context of Part IIA, for a risk to be realized all three aspects of the source-pathway-receptor linkage must be present, plausible and significant.
The outcome of this initial phase of works will define the requirements of future works.
All sites and scenarios are different, which as a result means that investigations need to be tailored to our client’s specific requirements. Therefore at TGEN we aim to ensure that all aspects of our site investigations not only address the specific requirements of our clients, but also address the demands of the local planning authority and the Environment Agency within the regulatory and planning framework.
If you would like further information on other aspects of the Contaminated Investigation process then please see the following pages. Alternatively if you require additional advice or have a question relating to a specific site please contact us at info@terragenenvironmental.co.uk