Potential Effects of Contaminants on Fraser River Sockeye Salmon

Hazard quotients were calculated for all chemicals <strong>of</strong> potential concern for which useableexposure data and toxicity reference values were available. Tables 4.17 and Table 4.18summarize the availability <strong>of</strong> water and sediment chemistry data, respectively, that areusable for evaluating the potential effects on sockeye salmon associated with exposure tochemicals <strong>of</strong> potential concern in the Fraser River Basin. For most areas <strong>of</strong> interest,habitat type, and brood year combinations, hazard quotients were calculated forconventional variables (e.g., pH and TSS), major ions, nutrients, and/or total metals. Insome cases, data were also available for chlorophenols, phenols, or cyanide (WAD).Hence, hazard quotients were calculated for only a subset <strong>of</strong> the aquatic contaminants thatwere identified in the Fraser River and its tributaries. To help address this limitation onthe available data and to address the lower reliability <strong>of</strong> the hazard quotients for certainchemicals <strong>of</strong> potential concern (e.g., nutrients, total metals) as indicators <strong>of</strong> potentialeffects on aquatic organisms (such a sockeye salmon), the hazard quotient data weresummarized for the pre-1990 and post-1990 periods to provide a basis for determining ifwater quality conditions have changed over the past two decades.4.5.1 <strong>Potential</strong> Risks to Sockeye Salmon Exposed to Surface WaterData on water quality conditions in the Fraser River Basin were obtained from theBCMOE EMS database (BCMOE 2010b; See Appendix 3). Data were obtained for 12 <strong>of</strong>the 15 geographic areas in the watershed (Figure 4.21). In addition, water quality datafrom Fraser River at Red Pass, a federal/provincial water quality monitoring station at theheadwaters <strong>of</strong> the Fraser River, were summarized to represent reference conditions.Water quality data were not available for the Harrison River, Nahatlatch, or Seton-Portageareas <strong>of</strong> interest. The available water chemistry data facilitated characterization <strong>of</strong> thelevels <strong>of</strong> conventional variables, major ions, nutrients, metals, cyanide, phenoliccompounds and chlorinated phenolic compounds concentrations in selected riverine andlacustrine waters (Tables 4.3 to Tables 4.15). A summary <strong>of</strong> available water chemistrydata for each <strong>of</strong> the life history stages (e.g., juvenile rearing) is presented in Table 4.17.The assessment <strong>of</strong> the water chemistry data was conducted for key life-history stageexposure periods (i.e., spawning and incubation, rearing, smolt outmigration and upstreamadult migration) for two distinct historical time periods: prior to and including 1990 (i.e.,pre-1990); and, 1991 up to and including 2010 (i.e., post-1990), where data wereavailable. The maximum hazard quotients for each chemical <strong>of</strong> potential concern in eacharea <strong>of</strong> interest, grouped by life-history stage and by pre-1990 and post-1990 time periods,are presented in Tables 4.19 to 4.31. In addition, the frequency <strong>of</strong> exceedance <strong>of</strong> theselected toxicity screening values was determined for each measured chemical <strong>of</strong> potential52