Fourteen
sediment cores were collected from 10 lakesspanning a large gradient of sockeye salmon returns (0-40 000 spawners km
-2) in Alaska and British Columbiain 1995-98 and 2002/03. The cores were analyzed for
210Pbto determine
sedimentation rates and
focusing factors.Polychlorinated biphenyl (PCBs) concentrations in the surface
sediments (0-2 cm) were highly correlated with thenumber of sockeye salmon returns to each nursery lake.For 2002/03, the correlation between PCB concentration andnumber of salmon spawners was best with no correctionfactors applied, but decreased considerably whencorrected for
sedimentation rates, and was improvedagain by correcting for
sediment focusing. Although
PCBconcentrations were similar in 1995-98 and 2002/03, thecongener patterns varied. Because salmon are the dominantsource of PCBs for most of these lakes, variation in
sediment congener pattern likely derives from variation incongener patterns carried by the salmon. Overall, totalPCB input by salmon has remained relatively constant since1995. Unlike temperate Great Lakes contaminant studies,the North American west-coast lakes dominated by salmonbio-transport showed no sign of recent decrease inPCBs.