This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This research addresses a multidisciplinary challenge at the intersection of sensing, environmental engineering and geotechnical engineering focused on obtaining valid and representative measurements of chlorinated solvents in the geoenvironment to facilitate cost-effective characterization, monitoring, and management strategies for sites contaminated with these compounds. These sites are subject to tremendous variability on multiple scales and frequently involve an array of additional chemicals. The technology currently available to assess chlorinated solvents at actionable levels involves costly and sophisticated instruments that can assess only select compounds, provide information over a limited spatial extent, and are available to relatively few. There is great potential to overcome this challenge and transform the state of field monitoring by taking advantage of recent technological advances in lasers, photonics, and telecommunications technology to deploy a distributed chlorinated solvent sensing system based on time-resolved Raman spectroscopy.
Achieving this vision is a multi-stage effort, and hinges on establishing a fundamental understanding of the factors affecting in-situ Raman spectroscopic measurements. Thus, the objective of this effort is to assess geoenvironmental influences on time-resolved Raman scattering observations of chlorinated solvents under controlled laboratory conditions indicative of those likely to be present in the field. Specifically, the work will build upon a recently developed innovative prototype fiber-coupled, time-resolved, Raman spectroscopy system, to 1) methodically examine the impact of multi-compound backgrounds, fluorophores, and sample turbidity on Raman observations, 2) provide insight into data analysis algorithms required to effectively collect Raman signatures in the presence of fluorophores, and 3) develop recommendations for field use of time-resolved Raman scattering for chlorinated solvent investigations, and optical spectroscopic analyses more generally.
Overall, progress toward optical spectroscopic monitoring systems that can be deployed at low cost over large areas, and yet provide specific analyses of a broad range of chemical compounds in nearly real-time will offer an unprecedented view of chemical fate and transport in the geoenvironment. More broadly, this work will advance a range of fields involving spectroscopic analyses of materials in complex, turbid, and/or fluorescence limited settings including water quality monitoring, precision agriculture, petroleum exploration, pharmaceutical quality control, analyses of biological systems, and assessment of homeland security threats and environmental disaster impact.
