A rapid method for the measurement of sulfur hexafluoride (SF₆), trifluoromethyl sulfur pentafluoride (SF₅CF₃), and Halon 1211 (CF₂ClBr) in hydrologic tracer studies

Abstract

[1] A rapid headspace method for the simultaneous laboratory determination of intentionally introduced hydrologic tracers, sulfur hexafluoride (SF 6 ), trifluoromethyl sulfur pentafluoride (SF 5 CF 3 ), Halon 1211 (CF 2 ClBr), and other halocarbons in water and gases is described. The high sensitivity of the procedure allows for introduction of minimal tracer mass (a few grams) into hydrologic systems with a large dynamic range of analytical detection (dilutions to 1:10 8 ). Analysis times by gas chromatography with electron capture detector are less than 1 min for SF 6 ; about 2 min for SF 6 and SF 5 CF 3 ; and 4 min for SF 6 , SF 5 CF 3 , and Halon 1211. Many samples can be rapidly collected, preserved in stoppered septum bottles, and analyzed at a later time in the laboratory. Examples are provided showing the effectiveness of the gas tracer test studies in varied hydrogeological settings.

Assessment of geochemical and hydrologic conditions near Old Yuma Mine in Saguaro National Park, Arizona, 2014–17

“…Samples were not analyzed from wells B-13-12 10BAC2 and B-13-12 10BAC3 because they did not contain detectable tritium. In addition, well B-13-12 10BAC3 was drilled using air rotary less than a year before the sample was collected; the air rotary drilling method is known to affect gas concentrations in water samples for several years following drilling (Busenberg and Plummer, 2010).…”

Stream metabolism and the open diel oxygen method: Principles, practice, and perspectives

“…In such case, it may be necessary to use tracer gas amenable to gas chromatography (GC) with electron capture detector for halogenated gases (e.g. Busenberg and Plummer ), GC mass spectrometry for noble gases (e.g. Wanninkhof et al ; Mackinnon et al ; Benson et al ), or other isotopic methods (e.g.…”

Estimated rates of groundwater recharge to the Chicot, Evangeline and Jasper aquifers by using environmental tracers in Montgomery and adjacent counties, Texas, 2008 and 2011

“…By using multiple tracers, however, samples from four wells completed in the Chicot aquifer yield apparent ages less than about 60 years (table 7), and the CFC-12 compound can be usable for groundwater of this age. The relatively small SF 6 and CFC concentrations measured even in samples of groundwater recharged less than about 60 years ago might be artifacts of well installation and development (Busenberg and Plummer, 2010), poor annular seals (U.S. Environmental Protection Agency, 1994), or a combination of these factors. Additionally, there may be nearby wells with multiple screened intervals in the aquifer(s), allowing for leakage of younger water to the older reservoirs of water and providing a conduit for cross-formational flow.…”