Reconstruction of the Pollution, and Limnological History of Douglas Lake (Michigan) using Biomarkers
thesisposted on 21.10.2015, 00:00 by Nnamdi L. Mojekwu
In order to reconstruct the pollution and paleolimnologic history preserved in the sedimentary record of Douglas Lake, a core was collected, dated, and analyzed using gas chromatography – mass spectrometry (GC–MS). The total lipid extract from the sediment samples were separated into three fractions for enhanced analytical resolution and target compounds within the fractions were quantified. Target compounds included polycyclic aromatic hydrocarbons (PAHs), Bisphenol A (BPA), and numerous n-alkanes. In interpreting the analyses of these compounds, a few points were highlighted: (1) forest fires were the principal sources of PAHs in the lake; (2) the concentration profiles of biomarkers reflected the response of the ecosystem to natural or anthropogenic environmental perturbations; and (3) the anomalously large, intermittent inputs of BPA were transported to Douglas Lake following fugitive releases into the atmosphere. Although further work is needed to assess the extent of contamination, the results from this study support the use of sediment cores in reconstructing the pollution history of lakes, especially where contamination monitoring is lacking.