Molecular Isotopic Tools for Environmental Research (MITER)

Funded by:  National Science Foundation, January 1, 2001 - December 31, 2005
Principal Investigators:  Timothy Eglinton, Associate Scientist, WHOI; Christopher Reddy, Assistant Scientist, WHOI; John Hayes, Senior Scientist, WHOI; Patrick Hatcher, Professor, OSU; Michael Freitas, Assistant Professor, OSU
Contact Information: Phone: 508-289-2627, Email: teglinton@whoi.edu

PROJECT SUMMARY
Our view of the fates of many toxic chemicals released into the environment is limited. In particular, we are not able to account quantitatively for these chemicals as they reside and move in soils and waterways. Interactions between contaminants and natural organic materials are one likely cause of this problem. Reactive contaminants can be bound to natural organic materials and, in that way, removed from view. Less reactive pollutants (e.g., hydrocarbons) can suffer the same fate after a preliminary attach by microorganisms has made them more susceptible to chemical binding (and potentially more toxic). These processes are poorly understood and largely unquantified. The bioavailability and toxicity of organically bound contaminants are virtually unknown and their long-term stability under changing environmental conditions is unclear. Understanding the mechanisms that control binding and release of contaminants is of critical importance if we are to effectively protect human health and the environment. Are contaminants that have have been bound to natural organic materials trapped permanently? Or are they likely to be released in the future? Even while bound, are the contaminants available to microorganisms and thus subject to biodegradation? To answer such questions, we must learn more about the abundances and characteristics of bound contaminants.

This collaborative proposal is focused on molecular interactions between pollutants and natural organic materials. We intend to provide new windows through which these interactions can be viewed. Specifically, we will use new techniques of isotopic tracing and new methods of analysis that are particularly suited to the study of complex, insoluble materials. Many, if not most, troublesome contaminants are produced from chemical feedstocks of fossil origin (natural gas, petroleum or coal). As a result of their age, they contain no 14C. We will use molecular-level 14C measurements (i) to detect these compounds and their metabolites in macromolecular organic matter in impacted sediments and soils and (ii) to follow the carbon into biological pools. This approach will be applied in tandem with 13C-, 2H- and 15N-labeling techniques and laboratory incubation experiments. We will closely study molecular interactions of targeted pollutants with natural organic matrices and will examine the biological uptake of organically-bound contaminants. These isotopic techniques offer a powerful, quantitative approach for the investigation of complex chemical processes and provide a tracer that can be followed at the molecular level by both nuclear magnetic resonance (NMR) and mass spectrometry (MS).

This proposal will foster collaboration between two institutions involving senior, mid-level, and junior scientists with complementary expertise in disciplines that impinge on the identified subject area. The PIs have been at the forefront in the development and application of molecular-isotopic techniques to biogeochemical problems. In addition to new insights into molecular-level processes provided by this approach, the MITER project will catalyze the development of new analytical capabilities that will facilitate the broader application of molecular-isotopic tools to environmental problems.