Potential Effects of Contaminants on Fraser River Sockeye Salmon

point and non-point source discharges are virtually unknown and the residence time <strong>of</strong>outmigrating smolts and upstream migrating adults in various sections <strong>of</strong> the FraserRiver mainstem is unknown for most stocks, it was assumed that the magnitude andduration <strong>of</strong> exposure to endocrine disrupting compounds originating from industrialand other sources are high for up-river stocks with the longest migration distances(i.e., those returning to the Quesnel, Bowron, and Nechako river watersheds),moderate for stocks with intermediate migration distances (i.e., those returning to theChilko, Seton-Portage, and Thompson river watersheds), and low for stocks with theshortest migration distances (i.e., those returning to the Pitt River and Cultus Lakewatersheds).6.1.7 <strong>Potential</strong> Risks to Sockeye Salmon Associated with Exposure toEndocrine-Disrupting Chemicals in the Fraser River BasinThere is a substantial body <strong>of</strong> scientific evidence demonstrating that many <strong>of</strong> thesubstances released to the environment due to human activities have the potential tomodulate or disrupt the endocrine system in fish. Because limitations on the availability <strong>of</strong>exposure data precluded implementation <strong>of</strong> a quantitative analysis, a qualitative approachwas used to evaluate the risks posed to sockeye salmon associated with exposure toendocrine disrupting compounds in the Fraser River Basin. This approach relied on aspatial analysis <strong>of</strong> the types <strong>of</strong> land uses that are typically associated with releases <strong>of</strong>endocrine disrupting compounds into aquatic ecosystems. The three types <strong>of</strong> land usesconsidered in this evaluation included (Pait and Nelson 2002):• Sewage treatment plants;• Pulp and paper mills; and,• Areas with high industrial activity/chemical contamination.Based on the results <strong>of</strong> the qualitative exposure assessment presented in Section 6.1.6, it isapparent that Fraser River sockeye salmon may be exposed to endocrine disruptingcompounds originating from multiple sources. For all three types <strong>of</strong> land use activities,the greatest quantities <strong>of</strong> endocrine disrupting compounds are likely to be released to theLower Fraser River Area <strong>of</strong> Interest. Significant releases <strong>of</strong> such chemicals also likelyoccur in the upper Fraser River mainstem, the Thompson River mainstem, and certainother tributaries within the watershed (e.g., Stuart River, Nechako River, Salmon River,Harrison River). As exposure areas and intensities are likely to be similar for all three land100