The Use of Field Deployable Instrumentation for the Monitoring of Explosives in Ground Water

The use of explosives at military installations has and does provide environmental concerns through soil and groundwater contamination, even after training or manufacturing activities have ceased. The concentration of munitions constituents in ground water is an ongoing concern that requires periodic monitoring. The traditional monitoring scenario requires that large amounts of sample (2 to 4 liters) be shipped overnight, under chain of custody control, to a fixed laboratory for analysis by regulatory-approved methods. Additionally, the samples must be packed on ice and be shielded from light to prevent any degradation of the samples during transport and storage. Once in the laboratory, the typical analysis and data reporting time is 30 to 45 days. This process results in data being unavailable to the customer, concentration data to be at least one month old, and expenses incurred for sample collection and shipping. The paper presents a field portable Gas ChromatographMass Spectrometer (GC-MS) for analysis of the explosives on-site. This methodology provides near real time, within approximately 1 hour of sampling, data of the concentration of munitions constituents in a ground water sample. Furthermore, the use of the mass spectrometer as a detection technique provides absolute confirmation of the munitions constituents, and provides a means to identify unknown compounds present in the sample that might otherwise provide false positive detections. This paper also presents two new techniques that are under investigation to be used as field portable instrumentation. The first new technique uses a portable mass spectrometer without a chromatographic interface to monitor all contaminants present in the sample. The second technique utilizes surface plasmon resonance to monitor a single analyte through an antibody-antigen interaction.