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http://hdl.handle.net/11375/21643
Title: | Concentrations of combustion derived contaminants in remote lakes: Recent trends and implications for site assessment |
Authors: | Benson, Andrew |
Advisor: | Slater, Gregory |
Department: | Geochemistry |
Keywords: | combustion;contaminants;remote lakes;site assessment |
Publication Date: | Feb-2009 |
Abstract: | Environmental quality and emissions guidelines are implemented due to their expected benefit for human and environmental health. However, implementation of such legislation requires knowledge of the behaviour and fate of the contaminants to be controlled. This thesis contributed to the overall understanding of atmospheric PAH deposition to remote lakes and the role atmospherically deposited contaminants play in site assessments which account for environmental pollution due to industry. In chapter 2, atmospheric PAH deposition derived from regional energy generation or industrial sources was found to be decreasing in recent sediments from Siskiwit Lake, Michigan, U.S.A. Considering that Siskiwit Lake is isolated from traffic and development, this supports recent theories which suggest that regional PAH deposition is being overprinting by local traffic sources in sub-urban or urban areas. This study also contributed to the understanding of perylene production in sediments by conclusively demonstrating increases in sedimentary perylene concentrations over a 20 year period. Moreover, kinetic modeling using 1st and 2nd order rate laws failed to accurately predict the concentration changes observed despite rate constants that were similar. This strongly suggested that perylene does not follow a simple concentration dependant kinetic reaction and is more likely controlled by complex kinetics perhaps involving biology. In chapter 3, the superiority of contaminant profiles in sediment cores over current dredge or grab sampling techniques was demonstrated. This was shown by successfully apportioning the source of contaminants to a northern lake as atmospheric deposition rather than point source release from the adjacent industrial facility. Contaminant profiles are able to constrain concentration changes with time and thus atmospheric deposition and point source contributions can be recognized. This is essential as chapter 3 also demonstrated that atmospheric deposition has the potential to produce sediment concentrations at or above current federal guidelines using standard dredge sampling techniques. Without the use of contaminant profiles these exceedences may be attributed incorrectly to industry which may face remediation costs or other fines associated with environmental contamination. This has implications for redefining sediment quality guidelines or currently accepted sampling methods. Moreover, remediation efforts for atmospherically deposited contaminants must differ from a point source release. Site remediation would be effective for a single release of contaminants however with a continuous source, as is the case with atmospheric deposition, remediation efforts must be focussed on the atmospheric contaminant emissions which can be a large distance from the site. |
URI: | http://hdl.handle.net/11375/21643 |
Appears in Collections: | Digitized Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Benson_Andrew_A_2009Feb_Masters.pdf | 6.52 MB | Adobe PDF | View/Open |
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