Evaluation of the snap sampler for sampling ground water monitoring wells for VOCs and explosives
A series of laboratory and field studies were conducted to determine the ability of the Snap Sampler to recover representative concentrations of VOC and explosives in ground water. For the laboratory studies, statistical analyses of the data (for each analyte) were conducted to determine if the concentrations of analytes in samples taken with the Snap Sampler were significantly different from known concentrations of the analytes in samples collected from a standpipe (i.e., control samples). For the field studies, concentrations of analytes in samples taken with the Snap Sampler were compared with concentrations of the analytes in samples taken using the EPA’s low-flow purging and sampling protocol. Again, statistical analyses were used to determine if there were statistically significant differences between the individual analyte concentrations in these samples. Two field trials were conducted for VOCs and one field trial was conducted for explosives. In the laboratory studies, the Snap Sampler recovered concentrations of VOCs that were comparable to those in the control samples after equilibrating the Snap Sampler for 3 days. Comparable concentrations of explosives were recovered after equilibrating the Snap Sampler for 24 hours. In the field studies, concentrations of VOCs and explosives were comparable to concentrations of these analytes in samples that were collected using low-flow purging and sampling.