Phase 2 Site Investigation

Phase 2 site investigation may be required to discharge a planning condition, investigate potential environmental liabilities, or to enable a more cost effective targeted remediation strategy.

The objective in all of these cases is to confirm whether the site is affected by ground contamination, and if so whether there is a significant risk to human health or the environment.

Site investigations will generally involve intrusive works such as the excavation of trial pits, the advancement of boreholes or installation of monitoring wells.

This allows soil and/or groundwater samples to be collected and sent for chemical laboratory analysis. Expert evaluation of the ground conditions encountered and the data obtained forms the basis of a quantitative risk assessment.

Adeptus carries out all phase 2 site investigation and contaminated land assessments in line with BS 10175 best practice guidance, and risk assessment to the standards required by Environment Agency publication CLR11.

'More' is not always better, and with experience and insight, it is possible to optimise an investigation regime, balancing costs constraints against the level of data and surety required.

All of the above should be based on a well defined conceptual site model (CSM) (generally developed at phase 1). Phase 2 site investigation should focus on reducing or eliminating uncertainties to refine the CSM.

The methods utilised will be determined by the nature of the site, access, geology, and the contaminant linkages of concern.

Phase 2 Assessment Objectives

Phase 2 Site Investigation is undertaken to obtain information on soil and groundwater conditions. This is usually necessary where a potential issue has been identified during an initial assessment.

Where a regulator, such as the local authority or Environment Agency is involved, the scope of a phase 2 investigation should be agreed with such parties before proceeding on-site, in order to ensure the relevant concerns are addressed and subsequent risk assessment will be acceptable.

Many investigations can be conducted efficiently with the use of simple machine-excavated or even hand-dug trial pits, which also allow visual inspection of the soil profile or any made ground. Where sampling at greater depths or groundwater monitoring is required, a borehole investigation and monitoring well installation may be necessary.

Phase 2 Site Investigation Report

Our phase 2 investigation reports are always prepared by the engineer supervising the works on site and retrieving the samples. Chemical concentrations returned from lab analysis are screened against generic or site specific assessment criteria, with overall assessment findings presented in a concise report and summarised in plain language.

Where necessary, we will also liaise with any third parties such as the local authority before commencement and after the works, to ensure the investigation objectives are properly established and addressed in the report.