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Sampling of VOCs with the BAT Ground Water Sampling System |
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| Authors: | Barry S Mines John L Davidson David Bloomquist Thomas B Stauffer |
| Institution: | Barry S. Mines is an instructor of civil engineering at the U.S. Air Force Academy (HQ USAFA/DFCE, USAFA,. CO 80840). He received his B.S. in civil engineering from the Virginia Military Institute, his M.E. in civil engineering from the Virginia Polytechnic Institute and State University, and his Ph.D. from the University of Florida. He was formerly a design civil engineer at Dover AFB Delaware and is a registered professional engineer in that state.;John L. Davidson is professor of civil engineering at the University of Florida (345 Weil Hall, Gainesville, FL 32611). He received his B.S. degree in civil engineering from the Queen's University, Belfast, Northern Ireland, and his M.S.C.E. and Ph.D. degrees in geotechnical engineering from Purdue University. He has been involved in teaching and research in the area of in situ geotechnical testing for 20 years.;David Bloomquist is assistant professor of civil engineering at the University of Florida (345 Weil Hall, Gainesville, FL 32611) and a registered professional engineer in the state of Florida. He received his B.S., M.E., and Ph.D. degrees in civil engineering from the University of Florida. His area of expertise is in geotechnical and concrete technology, while his specialty involves instrumentation and data acquisition.;Thomas B. Stauffer is chief of the Subsurface Chemistry Research Group at the Air Force Civil Engineering Support Agency (AFCESA/RAV, Tyndall AFB, FL 32403). He received his B.S. in chemistry at Capital University and his M.A. and Ph.D. from the College of William and Mary. His primary research interest is the environmental fate and transport of organic chemicals. |
| Abstract: | In the BAT ground water sampling system, a stainless steel probe with a porous filter element is pushed vertically to the desired sampling depth. An evacuated glass sampling tube is then lowered down the penetration rods where it makes contact with the filter via a hypodermic needle and draws a pore fluid sample. An investigation of the system was carried out at a number of sites contaminated by leaking underground gasoline storage tanks. Ground water samples obtained using the BAT system and adjacent monitoring wells were analyzed for volatile organic compounds (VOCs). Because the BAT system is an in situ penetration device with a small filter length, it is possible to determine variations in contaminant concentration with depth. BAT samples in general exhibited higher recovery of VOCs than did bailer samples from adjacent monitoring wells screened over large intervals. Much higher levels of VOCs were recovered when the probe was used with its 316 stainless steel filter than when using the high-density polyethylene (HDPE) filter. Significant sorption apparently occurred on the latter filter. Because the BAT sample tubes are sealed and remain a closed system, the in situ water pressure is maintained. No significant loss of VOCs was found in sampling tubes containing headspace. Samples from the upper tube in the cascaded setup with headspace recovered levels of VOCs as high, or in a few cases higher, than the lower, no-headspace tubes. |
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