This award provides funding to purchase a liquid isotope water analyzer for research and teaching at the College of Charleston. A Picarro wavelength-scanned cavity ring-down spectroscopy (WR-CRDS) analyzer, which is capable of simultaneously measuring oxygen and hydrogen isotopes in liquid water and vapor samples will be purchased. The system will be configured with the analyzer, autosampler and a liquid sample vaporizer. Additionally, the system includes a computer control module and assembly components. The instrument will be administered and maintained by the PIs with considerable roles for MS and undergraduate students to assist in maintenance. PIs will entertain users from other departments on an ad hoc basis. The analyzer will be put to use to better understand regional watershed hydrochemistry ? determining streamflow components and estimating residence times, coastal geological processes ? with emphasis on determining subsurface groundwater movement and submarine groundwater discharge, and cave and karst hydrology - water and hydrogen isotopes will be analyzed before and during rain events and over seasons to understand carbonate aquifers. The system will be made available to students in multiple disciplines. It will be used throughout College of Charleston?s Geosciences education program in which independent research is strongly emphasized. The analyzer will be used to provide near real-time stable isotope values for coastal water depth profiles, allowing students to understand coastal dynamics.
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The objective of this Instrumentation and Facilities project was to obtain an analyzer of liquid water isotope ratios and integrate it into the Hydrochemistry Teaching and Research group at the College of Charleston. This group is part of the Department of Geology and Environmental Geosciences (GEG), which has more than 100 majors, making it one of the largest undergraduate-focused Geosciences programs in the United States. The Principal Investigators, and several other faculty in GEG, also teach and direct research programs for the Master of Science in Environmental Studies program. The instrumentation was a Picarro L1102-i Liquid Water Isotope Ratio Analyzer (Picarro, Inc., Sunnyvale, CA) which uses an induction module cavity ring-down spectroscopy (IM-CRDS) system. The stability, ease-of-use, and simple calibration methodology has proven especially beneficial for teaching applications and faculty-student research collaborations. To date, calibration metrics have been established and preliminary data have been obtained from an urban watershed in the Charleston, SC metropolitan area. Filbin Creek is a freshwater tributary (roughly 6.4 km long) of the tidally-influenced Cooper River in North Charleston. Filbin Creek has its headwaters between a large parking lot at the North Charleston Coliseum and U.S. Interstate 526, to the Cooper River near Virginia Ave. The stream is fed by a number of groundwater seeps, precipitation, runoff, and tidal backwater from the Cooper River. The stream has a history of fish kills is currently listed as an impaired water by the Environmental Protection Agency. Water samples were collected from different stretches along this stream to determine various sources of water to the stream during wet and dry conditions between September and November of 2011. Precipitation water samples were also collected during this period. The water samples were filtered and analyzed for water isotopes using the Picarro water isotope analyzer acquired using funds from this Instrumentation and Facilities grant from the National Science Foundation. Results to date suggest that the measured changes in isotopic ratios in the stream water following rainfall reflect a surge in the volume of rainwater contributed via runoff. This has potential implications regarding how water and associated contaminants enter the stream; further data and analysis could help apportion how much each source of water contributed to the stream during different times of the year. A primary objective of the proposed work was to engage and train students in analytical methods for hydrology and geochemistry research. Under direction of the Principal Investigators, two students mastered the operation of the isotope analyzer and has prepared a more detailed user manual designed for students and experienced users alike. Approximately twenty other students in the Department of Geology and Environmental Geosciences (GEG) have benefitted through coursework experience and application of the instrument and its produced data. Water data collected from another research site will be analyzed by the graduate student to understand dynamics of groundwater-surface water interactions, and this instrument and its applications will be made available to future students in GEG and other College of Charleston courses.
