Field-Deployable Water Isotope Analyzer for Stream Sampling

The DOE is responsible for the remediation of 1.7 trillion gallons of contaminated ground water and 40 million cubic meters of contaminated soil generated from weapons production activities at 7000 discrete sites. In order to maintain site stewardship, the DOE requires improved instrumentation to study subsurface transport, develop models, and improve remediation strategies. In particular, measurements of water isotope ratios are critical to understanding the migration and flow of contaminated groundwater. Currently, these measurements require taking discrete samples to mass spectrometry laboratories, a process that is expensive and labor intensive. This project will develop a field-deployable water isotope analyzer that can provide rapid (< 20 minutes) quantification of dD and d18O to better than ±1.0 ¿ and ±0.3 ¿, sufficient for isotope hydrology studies. Phase I fabricated and deployed an analyzer that measured dD and d18O to better than 0.6 ¿ and 0.2 ¿ in < 16 minutes. A sampling system was developed to draw water from different sources and direct them into the instrument for quantification. The prototype system was deployed in a forest for 4 weeks and yielded the first-ever high-frequency quantification of isotope data over a long time period. Phase II will develop three analyzers for continuous measurements of 2H/1H and 18O/16O water isotope ratios in the field. Commercial Applications and other Benefits as described by the awardee: The analyzers would be used to validate subsurface transport models and provide continuous monitoring of water flow pathways. In addition to the DOE application to the remediation of contaminated facilities, the proposed sensor could be marketed for environmental research and medical diagnostics. The instrument also could be adapted to target the hydrology market.