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Chase, Jasmine Elizabeth

University of British Columbia

Fish biomonitoring by quantifying metals is a method with global applications for aquatic environmental health. Such studies measure anthropogenic metal contamination and often include an assessment of human health risks from fish consumption. However, these techniques are infrequently applied to complex marine environments and need more standardization, hindering data comparison over time. This study tests different methods to (1) optimize fish preparation methods for biogeochemical analyses to minimize metal contamination, (2) quantify metals in fish tissues to determine the best samples for metal biomonitoring, and apply these methods to wild pink Pacific salmon (Oncorhynchus gorbuscha) to (3) demonstrate applications and limitations of analyzing Pb isotopic compositions in concert with metal concentrations in marine fish biomonitoring. Analyses from 32 Pacific salmon reveal sample contamination from homogenization with porcelain tools but minimal variation between freeze- and oven-dried samples. Results from 34 certified reference material TORT-3 samples yield reproducible Pb isotopic compositions, supporting the use of TORT-3 as an in-house reference material for metal analyses in fish. The quantification of metals in organs and muscle from 23 pink salmon demonstrates that metal concentrations in muscle do not represent fish’s overall metal exposure. This thesis shows variations between gills and digestive systems that can be linked to brachial and intestinal uptake, while liver and kidney tissues contain metals acquired from both water and food. Lead isotopic compositions in wild pink salmon show spatial variation. Local Pb sources dominate in the northern Strait of Georgia while the impact of trans-Pacific Pb aerosols increases away from the B.C. coast. Lead isotopic compositions in different salmon organs also show variation related to longer Pb storage in the liver and kidney than in the gills and digestive system. These factors emphasize the importance of careful sample selection and the limitations of comparing datasets with varying types of samples. The methodological improvements presented here improve the accuracy of individual results and should be applied to all metal biomonitoring studies in fish. Combining Pb isotopic composition and metal concentration analyses in fish improves the robustness of environmental interpretations of marine fish biomonitoring by identifying broad trends in metal origins.

Text; Dataset

2024-06-03

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88404

Geological Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/