Deconvolution of Petroleum Contamination from Cultural Eutrophication
University of Michigan, Department of Geological Sciences Ann Arbor, MI, USA
Lake Erie has been subjected to extensive changes in the drainage basin, the lake environment and the biological communities over the last 150years. We found a sediment core collected from Eastern Lake Erie at 2003 and found no obvious odd numbered predominance in n-alkanes, suggesting petroleum contamination is most likely a significant source of n-alkanes. We proposed to analyze stable carbon and hydrogen isotope ratios of n-alkanes and n-fatty acids extracted from Lake Erie sediment core deposited between 1910 and 2003. Because stable isotope compositions are distinct for compounds originating from different sources, our analysis allow us to differentiate the biomarkers from petroleum contaminations and biological sources and thus to deconvolve the impacts from petroleum contaminations and culture eutrophications. Moreover, our study will provide an opportunity to compare the sources for n-alkanes before, during and after the 1940s, when the most severe petroleum pollutions occurred. The stable isotope compositions of short-chain n-alkanes will reflect the progress of in-situ bioremediation of petroleum contamination. Finally, the stable isotope compositions of n-fatty acids are not affected by petroleum sources and hence will improve our understanding about the response of a specific producer to significant environment changes at Lake Erie over the past century.
AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid