Development of an in situ Thermal Extraction Detection System (TEDS) for Rapid, Accurate, Quantitative Analysis of Environmental Pollutants in the Subsurface

The U.S. Environmental Protection Agency (EPA) in its publication Technology News and Trends in 2009 featured the Navy's work that saved 6 years and $3 million delineating chlorinated solvent plumes in soil and groundwater. The Navy used EPA's TRIAD process, which incorporates systematic planning, field analytics, and dynamic work strategies, during its hazardous waste site investigation. A direct sampling ion trap mass spectrometer was used to transport pollutants from depth to the surface for analysis. Although excellent data were obtained, the technology cannot collect and analyze semivolatile organics (SVOCs). Only Ion Signature Technology, Inc. (IST) has developed technology to collect VOCs and SVOCs at depth and transport the sample to the surface for analysis without organics adsorbing or condensing in the transfer line. In Phase I, IST found new material to develop a high temperature membrane inlet probe (MIP). When the MIP is at 300°C, organics efficiently desorb and extract from soil and at 100°C, collect from groundwater without bringing soil or groundwater to the surface for analysis. In addition, two new freeze traps and a new transfer line gas flow system were designed and tested, which met their respective specifications as established in the objectives. The goal of this Phase II SBIR is to integrate all of the disparate technologies into a turnkey system so that end users can "sniff" EPA method 8260 VOCs and 8270 SVOCs as the MIP is advanced into the subsurface at the rate of 2 cm/sec. The thermal extraction and detection system (TEDS) will incorporate electron capture and photoionization sensors to provide real-time, in situ chemical detection of pollutants. Once sensor responses exceed baseline signals, the MIP will stop automatically, with gas flow switching from the sensors to the freeze trap so that pollutants can be concentrated and quantified by gas chromatography/mass spectrometry (GC/MS). All analyses will be made online, at discrete depths, and recorded electronically for upload into site conceptual models. When combined with geological and hydrogeological data, conceptual models emerge that depict the location and rate of movement of subsurface pollutants. TEDS fits squarely within EPA's mission and importantly, EPA's TRIAD process. The objective is to provide defensible data to better manage site investigations and cleanups. EPA has shown that when projects employ the TRIAD process, which encompasses systemic planning, dynamic work strategies, and real-time chemical measurements, remediation costs are reduced.