Survey Of Contaminants In Suspended Sediment And Water In The Fraser River Basin

In response to increasing public concern over the effects of growing urbanization and industry in the Fraser River Basin, in June 1991, the federal government announced the Fraser River Action Plan (FRAP). [...] As part of FIL4P, the Environmental Quality Program is responsible for providing a baseline of the environmental conditions in the aquatic environment and measuring the effects of major pollution sources on the aquatic environment. [...] The Fraser River study region encompassed the mainstem of the Fraser River between Shelley and Yale, while the Thompson River study region encompassed the area between McLure on the North Thompson River and Savona on the Thompson River. [...] The main tributaries entering the Fraser River north of Prince George are the McGregor River, draining the Rocky Mountains, the Salmon River flowing from the north and the Willow and Bowron Rivers, draining the Cariboo Mountains. [...] At Lytton the muddy waters of the Fraser are joined from the east by the clear waters of the Thompson River before entering into the long, narrow, Fraser River Canyon that cuts through the barrier of the Coast Range 03.

In the field surveys, the in-situ size distributions of the suspended sediments of the Fraser and Thompson rivers were measured using a laser device and were compared with the size distribution of the dispersed primary particles. [...] On the other hand, if the sediment is in the size classes of silt and clay, it is classified as cohesive sediment and its transport is characterized by the interactions among the sediment grains and the formation of sediment flocs depending on the flow turbulence and physical-chemical processes of sediment water mixture. [...] Therefore, the transport of the contaminated sediment determines the fate of the contaminants and their interactions with the benthic organisms in the riverine environment. [...] For example, deposition of the contaminated sediment in sections of the river, where the bed shear stress and turbulence level are low, could 1 result in a temporary storage of the contaminants on the river bed and could impact on the bottom dwelling aquatic life and the other organisms connected by the food chain. [...] To ascertain that this is not due to the presence of solid particles (bio-solids) in the effluent, the size distribution of the solids in the effluent was measured and is shown in Figure 4. From this figure, we see that the size distribution of the solids in the effluent is slightly coarser than the primary particles, but not as coarse as the distribution measured for the 300 m transect.

Examines the mechanisms of natural riverine sediment production in the Northern River Basins Study area, together with the routine data for suspended sediment in the area's rivers, as background for the examination of sediment-associated contaminants. Topics examined include: the causative mechanisms and boundary conditions affecting the sediment regime, including area topography, geology, and hydrology; availability and adequacy of data on suspended sediments in the area; time trends of fluvial suspended sediment dynamics on a seasonal (open water and ice regime) and annual basis, over the long term, and in critical events; sediment sources, pathways, and fates, and sediment dynamics at basin-wide, reach, and site levels; sediment quality, including sediment-associated characteristics of pulp mill effluents and sediment-contaminant relationships; and implications for sediment-associated contaminants. Recommendations are made for monitoring and assessment of the sediment component of the area's ecosystem.