This is a past event.
Delineating the Chemical Composition of Dissolved Hydrocarbon Oxidation Products in Groundwater Plumes: Implications for Human Health and Aquatic Ecosystems
Petroleum hydrocarbons can infiltrate aquifers from accidental release at the surface or leaking underground storage tanks. Once entering the aquifer, biodegradation processes transform relatively non-polar petroleum compounds into polar, water-soluble products. Groundwater can carry these products significant distances from their source where they may enter the residential or municipal wells that nearly half of all Americans depend on for drinking water. Moreover, these polar plumes may discharge into surface waters where they can potentially affect aquatic ecosystems. While the adverse effects of hydrocarbons are documented and government agencies regulate them accordingly, little is known about the effects of hydrocarbon oxidation products (HOPs) on human health or aquatic ecosystems. Tracking the transport of these products and determining relationships between their molecular-level composition and toxicity is critical for risk assessment. The first part of the talk will discuss the application of optical spectroscopy for the identification of petroleum-derived dissolved organic matter (DOMHC) signatures that provide a rapid screening method for tracking polar plumes, the degradation state of DOMHC in the polar plumes, and their potential toxicity. Part two of the talk will show how we may use analytical techniques such as optical spectroscopy, ultrahigh resolution mass spectrometry, nuclear magnetic resonance spectroscopy, and black carbon analysis to map the biodegradation continuum of DOMHC in a polar plume at the molecular-level. This information enables us to make links between the potential toxicity of these products and the composition of the optical signatures that are used for rapid screening in the field.