Orcasphere

Persistent organic pollutants as chemical tracers for Puget Sound marine biota, Gina Ylitalo

Chemical tracers can be used to determine geographic ranges.  Persistent organic pollutants (POPs) like PCBs and PDBEs in Salish Sea herring (3 yr old males collected ’99 and ’04) showed elevated levels in Puget Sound relative to Georgia Strait, though difference was small in DDT.  West et al, 2008, Science of the Total Environment showed herring could be differentiated by these differences in contaminant concentrations.

Regional differences are shown by whole-body analysis of Chinook salmon from CA, Columbia River, and the Salish Sea.  PS resident Chinook (blackmouth) have [PCB]~90 ng/g  ww — twice non-resident PS Chinook.  CA Chinook were highest in [DDT] where it was used much more extensively than in the Northwest.

In NE Pacific killer whales, west coast transients have highest [DDT, PCB, PDBE].  SRKWs are most contaminated of residents (relative to Gulf of Alaska and Aleutian residents).  West Coast transients (feeding off CA coast) have highest DDT:PCB.  Breaking down SRKWs, L pod has highest DDT:PCB of all pods (not sure if K pod was assessed).  For PBDE:PCB, WC transients still highest and no significant difference between SRKW pods (L slightly higher ~0.7 vs 0.6).

Six gill sharks: [DDT]sum~40k ng/g lipid in mom and unborn pups that washed ashore in 2008, comparable to L pod concentration; local PS juveniles’  [DDT]sum is more similar to (~0.5x) J pod values.  This implies not only that the six gill mother was a Californian, but also that J pod really isn’t going too far south during any wintertime foraging excursions…