Low Cost, High Resolution Measurement of VOCs In Groundwater with ME/IMS Field Portable Technology

Costs for long-term monitoring are rapidly increasing, and now represent a significant percentage of the total and future site restoration costs. For example, in 2005, the U.S. Air Force spent 32% of its remediation budget on long-term monitoring systems, or $24.8M (compared to $51.8M for remedial systems). We have developed and tested a transformational prototype field sensor technology, Membrane-Extraction Ion-Mobility Spectroscopy (ME-IMS), which could revolutionize and greatly reduce the cost of monitoring volatile organic compounds (VOCs) in water and air. ME-IMS technology eliminates the need for collecting and shipping samples, and expensive offsite lab analysis. Lab testing has shown that a prototype sensor is capable of uniquely identifying over 115 different VOCs. ME-IMS technology can be used to quantify the most common environmental contaminants such as the hydrocarbons, trichloroethylene (TCE), carbon tetrachloride, tetrachloroethylene (PCE), dichloroethylene (DCE); contaminants related to gasoline spills, benzene, ethybenzene, tolulene, xylene; and trihalomethanes, the by-products of chlorination, with high reliability and sensitivity. Limit of detection for TCE is approximately 0.5 ppb; well below regulatory limits. The Department of Defense has estimated that the cost of sampling an individual well at one of their sites is currently $2,500/event. Costs for using ME/IMS technology are likely to be approximately 10 times less expensive because the VOC extraction and analysis can be conducted at the well head, eliminating the need to purge the well, collect a sample and ship the samples to an offsite laboratory for analysis. Preliminarily tests at the Department of Energy Y-12 site and a NASA site confirmed our ability to detect, identify and quantify VOCs in the field. ME-IMS technology could also be useful for characterizing and monitoring the migration of subsurface VOC vapor plumes.