A Dynamic Site Investigation: Adaptive Sampling and Analysis Program for Operable Unit 1 at Hanscom Air Force Base, Bedford, Massachusetts
In this study, field analytical instrumentation and methods were used to support a risk assessment study at the airfield at Hanscom Air Force Base (HAFB, Bedford, Massachusetts). The site investigation is part of an ongoing effort to determine contaminant risk to ground water from soil. The field tools supported a dynamic workplan/adaptive sampling and analysis demonstration. Over a two-week period, 601 soil samples were screened (30-sec/sample) for volatile organic compounds by direct measuring thermal desorption gas chromatography/mass spectrometry (TDGC/MS). From these results, 158 soil samples were selected for quantitative analysis by purge and trap GC/MS. In addition, quantitative analysis of 68 soil samples by TDGC/MS was made for polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Quantitative analysis times were 10-min/sample for PCBs and PAHs and 15-min/sample for VOCs. A field-practical microwave digestion procedure and an inductively coupled plasma/optical emission spectrometry method were used to analyze 121 samples for metals. Results of the dynamic site investigation and field method performance are presented. Finally, HAFB staff modified the ground water collection system into the treatment plant increasing the influent concentration. This project was funded through the U.S. Environmental Protection Agency and the Environmental Technology Initiative.