Chlorofluorocarbons, sulfur hexafluoride, and dissolved permanent gases in ground water from selected sites in and near the Idaho National Engineering and Environmental Laboratory, Idaho, 1994-97

From July 1994 through May 1997, the U.S. Geological Survey in cooperation with the
Department of Energy, sampled 86 wells completed in the Snake River Plain aquifer at and
near the Idaho N ationa1 Engineering and Environmental Laboratory (INEEL). The wells were
sampled for a variety of constituents including one- and two-carbon halocarbons.
Concentrations of dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11) and
trichlorotrifluororoethane (CFC-113) were determined. The samples for halocarbon analysis
were collected in 62-milliliter flame sealed borosilicate glass ampoules in the field. The data
will be used to evaluate the ages of ground waters at INEEL. The ages of the ground water will
be used to determine recharge rates, residence time, and travel time of water in the Snake River
Plain aquifer in and near INEEL. The chromatograms of 139 ground waters are presented
showing a large number of halomethanes, haloethanes, and haloethenes present in the ground
waters underlying the INEEL. The chromatograms can be used to qualitatively evaluate a large
number of contaminants at parts per trillion to parts per billion concentrations. The data can be
used to study temporal and spatial distribution of contaminants in the Snake River Plain aquifer.
Representative compressed chromatograms for all ground waters sampled in this study are
available on two 3.5-inch high density computer disks. The data and the program required to
decompress the data can be obtained from the U.S. Geological Survey office at Idaho Falls,
Idaho. Sulfur hexafluoride (SF6) concentrations were measured in selected wells to determine
the feasibility of using this environmental tracer as an age dating tool of ground water.
Concentrations of dissolved nitrogen, argon, carbon dioxide, oxygen, and methane were
measured in 79 ground waters. Concentrations of dissolved permanent gases are tabulated and
will be used to evaluate the temperature of recharge of ground water in and near the INEEL.