“…This was evident during the EEM, when significant increases of sediment PAH concentrations observed during Year 1 raised serious concerns with some government regulators (e.g., Environment Canada [EC] and Fisheries and Oceans Canada [DFO]; Walker et al, 2013aWalker et al, , 2013b. These concerns led to requests for cessation of remediation activities early in the project, even after only 1 year of monitoring data (Walker, 2014 Mass flux techniques help quantify sources of "mobile" versus "immobile" contaminants at remediation sites (Einarson & Mackay, 2001;Gibbs & Santillan, 2009;McDonald et al, 2016) and have been widely accepted by regulatory agencies (Interstate Technology & Regulatory Council [ITRC], 2010). Forensic source evaluations are also increasingly used for understanding origins of PAH contaminants in soils or sediments (MacAskill et al, 2016;Neff, Stout, & Gunster, 2005).…”