Potential Effects of Contaminants on Fraser River Sockeye Salmon

• Alkylphenol ethoxylates (APEOs; Rationale: Widely used, found in municipalwastewaters, pulp mill effluents, and urban run<strong>of</strong>f, known endocrinedisruptors, implicated in population level impacts on Atlantic salmon, andtreatment breaks them down into more toxic degradation products).<strong>Contaminants</strong> Posing Moderate Risk - The following substances were considered topose moderate risk to late-run sockeye salmon in the Fraser River Basin. Suchcontaminants are potentially contributing, along with other factors (such asoceanographic conditions, disease, water temperatures during upstream migration,etc.), to the decline <strong>of</strong> sockeye salmon in the study area:• Pesticides (triclopyr; Rationale: Increasing use in forestry sector and use iscorrelated with declines in sockeye salmon abundance);• Sodium ferrocyanide [Rationale: Increasing use <strong>of</strong> FireTrol 931 as fireretardant in forest applications, degrades to cyanide (which is toxic to fish), usecorrelated with declines in sockeye salmon abundance]; and,• Antisapstain chemicals [DDAC, IPBC, and borax-based chemicals; Rationale:Use appears stable, toxic to fish at low levels (i.e. approximately 1 µg/L), bestmanagement practices have reduced spills and run<strong>of</strong>f, and acutely toxic insediment at low levels; Szenasy 1999).<strong>Contaminants</strong> Posing Low Risk - The following substances were considered to poselow risk to late-run sockeye salmon in the Fraser River Basin. Such contaminants areconsidered to be the least likely to be contributing, along with other factors (such asoceanographic conditions, disease, water temperature, etc.), to the decline <strong>of</strong> sockeyesalmon in the study area:• Tributyltin (Rationale: Use restricted to ocean-going vessels and effects havedeclined in North America);• Anti-sapstain chemicals (sodium carbonate and2-(thiocyanomethylthio)benzothiazole; Rationale: Use is declining and bestmanagement practices have reduced spills and run<strong>of</strong>f); and,• Pesticide degradation products.110