The Risk Assessment essentially forms the core of the contaminated land investigation and assessment process. Potential risks identified from the findings of the Desk Study and Site Investigation is based on the existence of linkages between the sources, pathways and receptors identified. The significance of these risks must be addressed.
Essentially, the process aims to determine what risk, if any, is posed by the presence of contaminants through determining if there are pathways through which the contaminants may impact sensitive receptors, and if the risk is acceptable or not based on the proposed development.
In relation to contaminated land, there are three essential elements to any risk assessment and these are;
SOURCE (Contaminant) – a substance which is located in, on or under the land and has the potential to cause harm to human, health, water resources including controlled waters or the wider environment.
PATHWAY – the means or route by which a source of contamination can migrate to be affected by an identified source.
RECEPTOR – something which could come to harm from a contaminant and includes for example human health, water resources, surface water courses and linkages and the wider environment.
Phase 1 Desk Studies and Phase 2 Site Investigations are used to identify potential sources, pathways and receptors. Each pollutant linkage needs to be considered separately, understood and dealt with by appropriate recommendations.
The question of whether risk is acceptable in any particular case requires scientific and technical assessment of the circumstances on the site and the use of appropriate criteria to judge the level of risk combined with professional judgement.
The nature and level of risk is defined by variability in the condition and circumstances of any particular piece of land. The details of the use of the land itself, as well as the surrounding land, determine whether particular receptors and pathways are present and, if they are, the extent to which they might potentially be affected by contamination. The same concentration of contaminant can have widely differing implications in different circumstances. Risk Assessment allows this to be considered in a structured and pro-active way so that appropriate and cost-effective decisions are taken.
The second phase of the Contaminated Land Assessment process involves the conduct of an intrusive Site Investigation. The purpose of an intrusive Site Investigation is to investigate each potential source of contamination identified by the Desk Study. As such each site investigation conducted must be bespoke and designed to target the issues at each particular site in relation to the proposed development based on the Site Conceptual Model derived from the desk Study.
AXIS employs numerous different in-situ exploratory methods to carry out the intrusive Site Investigation. The method of investigation used can depend on a number of factors derived by the Desk Study including the sensitivity of the site and the surrounding area, the anticipated ground conditions, the nature and size of the site and the nature and type of potential contaminants.
- Hand Pits
- Hand Auguring
- Machine Excavated Trial Pits
- Rotary Drilling;
Samples of water, soil or other media found on sites are sent to INAB or UKAS accredited laboratories for analysis. All findings and certificates of analysis are combined with professional reporting procedures to present a comprehensive study of the site in question.
Remediation, waste management, waste removal, or other works required on site to remove any contamination found can also be provided for.