The main objective of this sampling program was to assess the actual effects of the spill on sediment quality by comparing the results of analyses of samples taken during and after the spill with those taken before. The distribution of the stations aimed to assess the impacts of the spill near the outlet of the overflow points and in fish habitat as well as several kilometers downstream, in a natural zone of sediment deposition in the delta of the Sorel Islands.
The document [Overview and summary interpretation of the monitoring of the spill] (http://ville.montreal.qc.ca/pls/portal/docs/PAGE/EAU_FR/MEDIA/DOCUMENTS/bilan_intercepteursudest_deversement2015.pdf) provides information to explain these measures.