When considering pathways of contaminants to pristine areas, the focus has been largely on atmospheric and oceanic transfer. In this study, sediment cores were used to study a far less investigated but very effective pathway of persistent organic pollutants (POPs) to pristine ecosystems: the biotransport by migrating sockeye salmon (Oncorhynchus nerka). To quantify the importance of salmon as a biotransporter of contaminants, surface sediments of lakes in Alaska and British Columbia spanning a wide gradient of salmon returns (0--40,000 salmon per km2) were analyzed. Regressions of contaminant concentrations in the surface sediments with the number of returning salmon revealed a very strong, positive relationship. Especially for the lakes that received high numbers of spawners, sockeye salmon were found to be a more important source of PCBs (Polychorinated biphenyls) than the atmosphere. Furthermore, the quality of the relationship of PCB concentration with sockeye salmon spawners was found to be best for PCB congeners that are most abundant in sockeye salmon muscle tissue. Down-core profiles were analyzed to examine if the relationship between contaminant concentrations and sockeye salmon numbers can also be found historically within a lake. To investigate this question, contaminant concentrations in the 210Pb dated sediments were compared to historical sockeye salmon counts provided by authorities in Alaska and British Columbia. The results indicate that although it is possible to find the relationship between sockeye salmon spawners and contaminant concentration in down-core profiles, it is influenced by numerous factors. Such factors can arise from contaminant patterns that result from sources other than salmon, or simply very low sedimentation rates, which lead to very low resolutions in the down-core profiles.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/29407 |
| Date | January 2006 |
| Creators | Krummel, Eva M |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 174 p. |
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