Tier 1 Ecological Risk Assessment of a Contaminated Rail Corridor

A screening level ecological risk assessment (ERA) was conducted for a contaminated rail corridor in British Columbia. The purpose of the ERA was to demonstrate the utility of British Columbia Tier 1 ERA methodology for identifying contaminated sites with unacceptable ecological risks requiring remediation andor risk management. The methodology applies a weight of evidence approach to characterize ecological risks with risk quotients and site observations serving as the two lines of evidence. More weight is placed on field observations because risk quotients are less site-specific and over estimate risk due to multiple conservative assumptions. A major limitation of the provincial Tier 1 method is that the biological survey methodology recommended is too qualitative to provide the information necessary to reliably confirm or refute the presumption of risk indicated by risk quotient results. More quantitative biological survey methods are needed to identify adverse ecological effects and causative links to site contamination.