Date of Completion
Michael T. Hren
Field of Study
Doctor of Philosophy
One of the critical challenges facing modern environmental chemistry is how to identify sources, process of formation, and transport of organic compounds and pollutants in the environment. In recent decades, molecular and stable isotopic analysis of individual organic biomarkers, produced by living organisms, has emerged as a novel tool for identifying sources and processes associated with the synthesis of biological compounds. Specifically, this thesis focused on the questions related to processes controlling the production and movement of n-alkanes produced in plant leaf waxes and PAHs produced through the partial combustion of organic material. The aims of this thesis were to use compound-specific isotope analysis of these organic molecular biomarkers to understand how environmental changes are recorded, determine source materials, and evaluate potential methods of transport through the environment. Chapters 3 and 4 used stable hydrogen (δD) and carbon (δ13C) isotopes of n-alkanes produced by leaf waxes to determine how differences in taxonomic class are recorded and how these biomarkers are preserved in fluvial sediments. This study found that n-alkanes from individual plants record plant specific differences in photosynthetic processes and physiology whereas n‑alkanes preserved in fluvial sediments can identify large scale ecosystem changes. In Chapter 5, the concentrations, δD and δ13C of 16 EPA priority PAHs were measured from samples collected from around the states of Connecticut and Rhode Island. Using a multivariate approach to source identification, this study found that PAHs extracted from sediments and soils in Connecticut were sourced from a complex mixture of vehicular exhaust, coal burning exhaust, and industrial emissions. These projects represent a significant contribution to the understanding of carbon mobility over the earth surface with broad applications to environmental pollution tracing and paleoenvironmental reconstructions.
Oakes, Abigail M., "Application of Compound Specific Stable Isotope Analysis to Spatial and Temporal Tracing of Organic Molecular Biomarkers through the Environment" (2017). Doctoral Dissertations. 1442.