In Situ Isotope Hygrometer for Mapping and Monitoring Hydrogeologic Processes

Isotope hydrology is a powerful method for tracing the transport and dispersion of contaminants in the subsurface. Although widely applied, the method depends on sample analysis in specialized laboratories equipped with expensive and complex analysis tools. Instead, this project will develop small rugged analyzers suitable for on-site monitoring, which would significantly boost applications of isotope hydrology. The new instrument will cost-effectively measure d18O, d17O and dD in water samples with a targeted precision below 1 per mil. The sensor will operate in real time and will need no sample preparation. In Phase I, telecommunication infrared laser diodes will be combined with photoacoustic spectroscopy to measure the isotope sample composition. A shoebox-sized device is targeted that will enable the eventual commercialization of rugged fieldable instrument at a targeted retail price of $10K. Commercial Applications and other Benefits as described by the awardee: A cost-effective, fieldable isotope hygrometer would be a valuable tool in understanding surface water movement and interaction with groundwater. It could be utilized for mapping aquifers and conserving water supplies. Because water is of enormous environmental importance, the proposed compact sensor technology should find applications in food product authenticity, paleoclimatology, atmospheric chemistry, and biomedicine.