Integrated environmental risk assessment for petroleum-contaminated sites - a North American case study

Development of petroleum industries is associated with a number of environmental concerns. Among them, soil and groundwater contamination by petroleum products is of major concern. In this study, an integrated risk assessment approach is proposed for evaluating environmental risks derived from petroleum-contaminated sites. The proposed approach is composed of (i) a hydrocarbon spill screening model (HSSM) which is used for simulating immisicible flow of released hydrocarbons in vadose zone, formation of lens in capillary fringe, dissolution of pollutants at water table, and transport of the pollutants to receptors, and (ii) a fuzzy relation analysis (FRA) model which is developed for comprehensively evaluating risks caused by a number of pollutants with different impact characteristics, based on the HSSM results. This hybrid HSSM-FPA approach was applied to a case study for a petroleum-contaminated site in western Canada, where soil and groundwater was contaminated by industrial wastes containing benzene, toluene, ethylbenzene and xylenes (BTEXs). The results suggest that the HSSM-FRA can provide insight into the potential risk to the receptor of concern downward the acquifer and can serve as a basis for further remediation-related decision analysis.