Due to industrialization over the past 100 years, the sediments at the bottom of the Lachine Canal and Bay have become contaminated. This study investigated the heavy metal accumulation mechanisms within the Lachine Canal sediments and was carried out in three phases. Phase I is covered in the present article, while phases II and III will be discussed in a following paper. During Phase I, 28 parameters were measured on 44 sediment samples collected along the Lachine Canal and Bay. The results revealed the presence of a wide variety of both organic and inorganic contaminants. Heavy metals such as Zn > Pb > Cr > Ni > Cu > Cd (in order of decreasing abundance) in addition to organic contaminants (PAHs > MAHs > PCBs) were found in high concentrations exceeding background concentrations and various quality criteria levels. The total load of both organic and inorganic contaminants was found to be higher in the canal than in the bay zone. Correlation analysis was performed to evaluate sediment assessment values with respect to known adsorptive phases such as % clay fraction, TOC (Total Organic Carbon), and % CaCO3. Although a positive correlation existed between % clay fraction or TOC and the total cumulative load of heavy metals, the correlation could not be assessed as conclusive. Significant correlations were obtained between Pb, Ni, and Zn and the carbonate content of the sediments. Pollution Indices (PI) were used according to the format proposed by Canadian authorities and as such were evaluated as incomplete.