Groundwater-Quality and Quality-Control Data for Two Monitoring Wells near Pavillion, Wyoming, April and May 2012 by Peter R. Wright, Peter B. McMahon, David K. Mueller, and Melanie L. Clark, 2012, U.S. Geological Survey and U.S. Department of the Interior, In cooperation with the Wyoming Department of Environmental Quality, Data Series 718
Well MW01 was completed to a depth of 785 feet (ft) below land surface (bls) and well MW02 was completed to a depth of 980 ft bls. … Two groundwater-quality samples were collected from well MW01—one sample was collected after purging about 1.5 borehole volumes, and a second sample was collected after purging 3 borehole volumes. … Groundwater-quality samples were analyzed for field water-quality properties (water temperature, pH, specific conductance, dissolved oxygen, oxidation potential); inorganic constituents including naturally occurring radioactive compounds (radon, radium-226 and radium-228); organic constituents; dissolved gasses; stable isotopes of methane, water, and dissolved inorganic carbon; and environmental tracers (carbon-14, chlorofluorocarbons, sulfur hexafluoride, tritium, helium, neon, argon, krypton, xenon, and the ratio of helium-3 to helium-4).
TestAmerica reported methane concentrations ranging from 20 to 30.5 mg/L (or 20,000 to 30,500 micrograms per liter) for environmental sample 1 and the sample 1 replicate, and the USGS Reston Chlorofluorocarbon Laboratory reported methane concentrations ranging from 26 to 28 mg/L. [Emphasis added]
[Refer also to:
Source: Slide #96 in From Cape Town to the Yukon September 22, 2012]