Application of Advanced Sensor Technology to DoD Soil Vapor Intrusion Problems

Abstract

The public reporting burden for this coll.etion of infOfmatlon is tstlm attd to av..-a~ 1 hour per response, including the time for reviewing in.ttnJction:, :earching exi:ting data :ourcc:. gathering and maintaining dle data needed, and COt'Tl)letiog and revtewing the collection of information. Send commtntc regarding thic burden utima1e or any other aspect of thic co llection of inform.-bon, including suggestions for reducing the burden, to the Department of Defense. Executive Servitas and Commu nie.ations Oir.etorate (0704•0188). R"pondents c.hould be aware that notwithstanding any othet prov1sion of law, no .,.,uon shall be subject to any penalty fo r failng to comply with a col!ection of information if it does not d isplay a curtentfy valid OMS control number. This study demonstrated the use of a unique prototype gas chromatograph with sensor array detection, the analytical components of which are microfabricated from Si (micro-GC), for analysis of indoor air concentrations of trichloroethylene (TCE) at low-and sub•ppb levels, related to vapor intrusion (VI) applications. The objectives of this study were to demonstrate the performance of the prototype micro-GC in two operating modes: portable mode for forensic and spatial monitoring; and fixedlocation mode for longer term temporal monitoring (exposure estimation). Results from the micro•GC and from T0-15 reference samples were compared. Above the mitigation action level (MAL; 2.3 ppb), the micro-GC accurately determined TCE under complex field matrix conditions. Below the MAL, TCE micro-GC determinations were positively biased due to unresolved interferences. This study stands as the first of its kind, where micro-GC instrumentation was shown capable of sustained, reliable , automated measurements of a trace-level component (TCE) in a complex VOC mixture in real-world environments. 15. SUBJECT TERMS vapor intrusion, micro-gas chromatograph, indoor air analysis 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF a.