Electrical resistivity tomography, electromagnetic induction, and ultraviolet optical scanning tool data collected at Malmstrom Air Force Base, Great Falls, Montana, August 28–August 31, 2023

The U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force Civil Engineer Center (USAF/CEC), conducted a pilot study at Malmstrom Air Force Base (MAFB) to evaluate the utility of two non-invasive geophysical techniques for detecting hydrocarbons in subsurface materials. Electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys were completed August 28–29, 2023, along 7 transects overtop contaminated and uncontaminated sites for comparison. Additionally, the USGS completed ultraviolet optical scanning tool (UVOST) soundings and collected soil samples from temporary boreholes to validate geophysical survey results. A total of 11 UVOST soundings and 7 boreholes were completed August 28–31, 2023. Two soil samples from various depths were collected from each borehole for a total of 14 samples. Ten quality assurance/quality control samples consisting of 2 field equipment blanks (1 per day), 4 replicate soil samples (2 per day), and 4 trip blanks (2 per day). Soils were tested for volatile organic compounds, semi-volatile organic compounds, gasoline range organics, diesel range organics, metals, and per- and polyfluorinated substances (PFAS/PFOA).

美国地质调查局（U.S. Geological Survey, USGS）与美国空军土木工程中心（U.S. Air Force Civil Engineer Center, USAF/CEC）合作，在马尔姆斯特伦空军基地（Malmstrom Air Force Base, MAFB）开展一项试点研究，以评估两种非侵入式地球物理技术检测地下物质中碳氢化合物的应用效用。2023年8月28日至29日，研究团队沿7条断面完成电阻率层析成像（Electrical Resistivity Tomography, ERT）与电磁感应（Electromagnetic Induction, EMI）测量，覆盖受污染与未受污染场地以开展对比分析。此外，美国地质调查局还完成了紫外光学扫描工具（Ultraviolet Optical Scanning Tool, UVOST）探测，并通过临时钻孔采集土壤样本，用于验证地球物理测量结果。2023年8月28日至31日，共计完成11次UVOST探测与7个钻孔。每个钻孔采集2份不同深度的土壤样本，总计14份样本。本次研究共设置10份质量保证/质量控制样本，包含2份现场设备空白样（每日1份）、4份平行土壤样本（每日2份）以及4份行程空白样（每日2份）。研究人员对土壤样本开展了挥发性有机物、半挥发性有机物、汽油馏分有机物、柴油馏分有机物、金属以及全氟和多氟烷基物质（Per- and Polyfluorinated Substances, PFAS/PFOA）的检测。