If your Phase 1 Desk Study identified one or more potentially significant risks to human health, the environment and/or buildings, then a Phase 2 Site investigation is typically carried out to refine the preliminary conceptual site model (CSM) created at Phase 1. This will usually be needed to satisfy regulators overseeing the project – such as local planning department, Environment Agency/SEPA or building control.
A Phase 1 Desk Study is necessarily conservative and should always err on the side of caution – it is the purpose of the Phase 2 Site Investigation to collect information to reduce the uncertainties associated with Phase 1 and to challenge assumptions made during its preparation.
The Phase 2 Site Investigation will use intrusive techniques such as borehole drilling and trial pitting, combined with other sampling and testing to help discover whether contamination assumed to be present on the site is indeed there, it’s extent and/or severity.
The qualitative assessment of risks undertaken in the Phase 1 preliminary CSM is improved using the Phase 2 site-won data and a quantitative assessment of risks can be undertaken – a generic quantitative risk assessment (GQRA) or detailed quantitative risk assessment (DQRA) as required.
Ultimately, the outcome of a Phase 2 Site Investigation should be an accompanying report which provides the client with details of any significant risks identified at the site with regard to human health, the environment or buildings. There should also be detail as to how risks perceived as potentially significant at Phase 1 were ruled out. Where significant risks are identified, the report should also provide recommendations as to what is required next – this may be further site investigation, or remedial works to mitigate against such risk.
Risk mitigation can be undertaken via a variety of remedial techniques – Soilutions believe a remedial options appraisal is a key part of a Phase 2 report where significant risks are identified and include them by default in reporting.
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