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Sampling Trace-Level Organic Solutes with Polymeric Tubing Part 2. Dynamic Studies |
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| Authors: | Louise V Parker Thomas A Ranney |
| Institution: | Louise V. Parker;is a research physical scientist at the U.S. Army Cold Regions Research and Engineering Laboratory (72 Lyme Road, Hanover, NH 03755-1290). She received a B.A. in microbiology from the University of New Hampshire and an M.S. in food science and nutrition (food microbiology) at the University of Massachusetts. Her research interests are ground water sampling and material interactions. She is a member of the of Ground Water Scientists &Engineers Division of the National Ground Water Association and has been active in ASTM subcommittee D18.21 on ground water and vadose zone investigations. Thomas A. Ranney;is a staff scientist with the Science and Technology Corp. (P.O. Box 127, Hanover, NH 03755). He received a B.S. in education from Castleton State College and an M.S. in plant and soil science from the University of Vermont. His research interests are evaluating environmental sampling procedures and development of analytical methods. |
| Abstract: | This is the second part of a study conducted to determine whether polymeric sampling tubing can affect organic analyte concentrations during a sampling event. In this part of the study, we looked for sorption and desorption of tricholoroethylene (TCE) and leaching of organic constituents in water pumped through five types of polymeric tubing. The materials tested were a rigid fluoropolymer, a flexible fluoropolymer, low-density polyethylene (LDPE), and two plasticized polypropylene tubings. The effects of tubing length and flow rate were examined. The least sorptive tubings, both initially and at equilibrium, were the fluoropolymers. However, in some instances the LDPE tubing had little effect on TCE concentrations. This was when a slow flow rate was used to sample relatively shallow wells (50 feet 15 m] or less) or when a faster flow rate (1 L/min) was used to sample wells that are less than 500 feet (152 m). Further testing is recommended using more sorptive analytes. Using high performance liquid chromatography (HPLC), we were unable to detect any constituents leaching from any of the tubings used in these studies, even when a slow flow rate was used. However, desorption of sorbed analytes is a concern for all the tubings tested, including the rigid fluoropolymer. |
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