Site Assessment

Phase 1 Site Assessment - Preliminary Risk Assessment for Land Contamination
Once the need for risk assessment of a site has been identified, it is always necessary to carry out a preliminary risk assessment. This is to determine what the context and objectives are for the risk assessment; what the outline conceptual model is for the site; what potential unacceptable risks can be identified and; what further action is appropriate.

Information collection typically includes a desk study and site reconnaissance and may include additional desk study and exploratory site investigation.
The Phase 1 assessment collects and reviews largely desk-based information to prepare an initial conceptual model to identify possible pollutant linkages. This information includes a site’s historical development, geological and hydrogeological setting, pollution history and licensed activities.
Defence related sites in particular require a thorough historical overview due to the extreme hazards posed by explosives, unexploded ordnance and chemical weapons agents. We have our own extensive information archive of defence related sites throughout the country that may not be available in the public domain.
A thorough walkover survey will be conducted as part of the Phase 1 works to establish existing conditions. This can also assess environmental housekeeping standards and possibly identify evidence of potentially contaminative processes operating on or around the site.
Using criteria appropriate to the risk assessment context a report evaluating possible pollutant linkages is produced that will decide whether or not further action is needed, for example the scope and scale of further risk assessment.
BAE Systems Environmental also offers a professional, unbiased peer review of existing geo-environmental reports in light of current legislation and good practice.

Phase 2 Site Assessments - Generic Quantitative Risk Assessment
At the beginning of this phase an outline conceptual model and context for the risk assessment will have been established. At the end of this phase the following decisions will have been made: what pollutant linkages can be evaluated using generic assessment criteria; whether unacceptable risks associated with these linkages can be identified and; what further action is appropriate.
The availability and appropriateness of generic assessment criteria (derived using largely conservative generic assumptions about the characteristics and behaviours of sources, pathways and receptors) to simplify the assessment are considered. BAE Systems Environmental uses ‘Tier 1’ generic soil assessment criteria for a range of contaminants, including explosives.
Following development of an investigation and sampling strategy further information about the site is collected through intrusive investigation.
BAE Systems Environmental offers a range of exploratory hole techniques to obtain in-situ soil and groundwater data and recover samples of soil for chemical and geotechnical testing. Monitoring of groundwater and the soil-gas regime within boreholes and recovery of water and gas samples for laboratory analysis is also undertaken.
We are fully insured for work involving explosives and our engineers are trained in the recognition and remediation of explosives and unexploded ordnance.
We pride ourselves in providing a quality, cost effective service within ISO 9001, ISO14001 and Investors In People accreditation and supported by our UKAS chemical testing laboratory.

Phase 3 Site Assessments - Detailed Quantitative Risk Assessment
There could be pollutant linkages for which generic criteria are not available or appropriate, or which are more conservative given the actual circumstances of the site. Detailed site -specific assessment criteria may need to be developed to estimate and evaluate the risk.
BAE Systems Environmental uses the latest Government guidance to conduct Phase 3 assessments that build on the findings of the Phase 1 and Phase 2 assessments. This may include further focused site investigation to collect and assess information about the contaminant and ground and groundwater conditions and/or the use of modelling to assess the risk.
We are acknowledged UK experts in the evaluation and management of risks associated with potential explosives and munitions related contamination.   

The Outcome
Depending on the context of the assessment and the site circumstances a final report can cover terms of reference; site perspective; initial conceptual site model; investigation and sampling strategy; soil and water quality; soil-gas regime; updated conceptual site model; environmental risk assessment; implications for redevelopment.

The Next Stage
If unacceptable risks are not identified no further action is required. If there are unacceptable risks feasible remediation options are identified and a remediation strategy developed that addresses all relevant pollutant linkages. Assessment using generic assessment criteria may also lead straight to options appraisal. 
Further investigation may be required to assist in the evaluation and selection of remedial measures.