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. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21643 |
| Date | 02 1900 |
| Creators | Benson, Andrew |
| Contributors | Slater, Gregory, Geochemistry |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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