Framework for preliminary risk assessment of brownfield sites

The complexity of hazards, risk and environmental legislation surrounding the reuse of brownfield sites necessitates a preliminary risk assessment prior to their redevelopment. Most prevailing efforts have been targeted at indepth site investigations, which are often costly, time-consuming, and may not be required at the early stages of a site development. However, there is a collective absence of knowledge, methods and computer models that can present a complete framework to carry out a preliminary risk assessment that is simpler, quicker and sufficient, not only for risk assessor but also effectively communicative for a diverse range of stakeholders with or without risk assessment expertise. Therefore, this study aims to bridge this gap by designing and creating a framework, by not only identifying hazards but also exposing the degree of presence. Sixty-five potential hazards have been identified from a comprehensive literature review. A questionnaire survey was then shared with brownfield site experts (n = 76) that asked then to rank the priority of the potential hazards. Kendall's W test and Kruskal-Wallis H test were subsequently conducted to determine the level of agreement among the respondents. Mean weightings were calculated by using the Voting Analytic Hierarchy Process (VAHP) to prioritize the potential hazards from 'more likely' to 'least likely'. Based on this information, the framework has been developed. It is anticipated that the framework can assist professionals to conduct a preliminary assessment of brownfield sites, which enables them to gain informative and rapid guidance on any potential liabilities or risks related to a site's suitability for acquisition or redevelopment. In this context, the framework outlines a systematic structure to collect appropriate data and information in the three main categories which are sources, pathways and receptors.