Chemistry of unsaturated zone gases sampled in open boreholes at the crest of Yucca Mountain, Nevada: Data and basic concepts of chemical and physical processes in the mountain

Worldwide Occurrence and Fate of Chlorofluorocarbons in Groundwater

“…However, recent analyses of volcano gases in Italy and Japan did not detect elevated concentrations of CFC-11 and CFC-12 (Jordan et al, 2000), and volcanic hot springs in Arkansas had CFC-11 concentrations not exceeding the detection limits of 3 pg L -1 (Thompson and Hayes, 1979). CFC concentrations in gas samples from the unsaturated zone in boreholes in tertiary volcanic rocks at Yucca Mountain were all below concentrations in modern air (Thorstensson et al, 1998). Volcanism thus can be excluded as a mechanism leading to elevated CFC concentrations in groundwater.…”

Magmatic gas emissions at Holocene volcanic features near Mono Lake, California, and their relation to regional magmatism

“…The entrained air and CO 2 mix within the edifice in a regime where turbulent stirring dominates over molecular diffusion, explaining why the δ 13 C-CO 2 values at all thermal sites sampled are near −4.9‰, independent of CO 2 concentration. Topographic/thermal effects have been frequently invoked to explain air circulation through other mountains, volcanic or not (e.g., Woodcock and Friedman, 1979;Thorstenson et al, 1998).…”

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

“…The atmospheric lifetimes of Halon 1211 and 1301 are 16 and 65 years, respectively [ Forster et al , 2007]. Halon 1211 was detectable in unsaturated zone gases 15 years after it was introduced in a well at Yucca Mountain, Nevada [ Thorstenson et al , 1998] and in groundwater 5 years after it was introduced in a fractured rock aquifer in Virginia (this paper). Some important properties of these tracers are summarized in Table 1.…”

“…Contamination with drilling fluids and air can be a persistent problem in some wells that have not or cannot be properly purged [ Plummer et al , 2004]. Halon 1211 was detectable above background levels of <1 pptv in unsaturated zone gases 15 years after it was introduced in a well at Yucca Mountain, Nevada [ Thorstenson et al , 1998]. The presence of Halon 1211 in air and groundwater do not interfere with the analysis of SF 6 and CFCs, but age interpretation is probably invalid.…”