The sediment was seriously contaminated in lac aux Brochets on Gordon Creek, and offshore from the pulp and paper (P&P) industrial landfills and nearby train tracks, with arsenic, chromium, copper, iron, nickel, total phosphorus, lead and zinc all exceeding the interim and established Provincial and Federal guidelines for the lowest level for the protection of aquatic life. Manganese exceeded (Quebec) Provincial guidelines for severe level effects, showing significant pulses offshore train tracks and industrial landfills. Further downriver, leachate from a municipal landfill, and excess nutrients from forestry activities upstream in Fournier Creek affected water and sediment quality. General metrics of the physico-chemical environment were reliable predictors of areas showing elevated metal contamination in sediment and water; surveys of aquatic invertebrates were less reliable. Suggestions are offered regarding the control of contaminant releases from landfill wastes, and procedures that could reduce current and future industrial discharges.