Improvement of the sediment ecosystem following diversion of an intertidal sewage outfall at the Fraser river estuary, Canada, with emphasis on Corophium salmonis (amphipoda)

摘要

Primary treated sewage effluent from the city of Vancouver, Canada was deposited directly onto the intertidal ecosystem of Sturgeon bank, Fraser river estuary between 1962 and 1988. In response to the degraded sediment conditions an azoic zone de- Veloped near the discharge outfall. Effluent discharges into the intertidal zone were almost completely stopped in 1988 with the Construction of a submerged outfall. Our studies, conducted between 1994 and 1996, showed considerable improvement in the Environment of the mudflat ecosystem,, including increased dissolved oxygen, decreased sediment chlorophyll, decreased organic Material in the sediment, reduced heavy metals in surficial sediment and increased grain size.