Water-chemistry and on-site sulfur-speciation data for selected springs in Yellowstone National Park, Wyoming, 1994-1995

Forty-two water analyses are reported for samples collected at 8 hot springs and their
overflow drainages, two geysers, and two ambient-temperature acid streams in Yellowstone National
Park during 1994-95. These water samples were collected and analyzed as part of the initial
research investigations on sulfur redox speciation in the hot springs of Yellowstone and to document
chemical changes in overflows that affect major ions, redox species, and trace elements. The sulfur
redox speciation research is a collaboration between the State University of New York (SUNY) at
Stony Brook and the U.S. Geological Survey (USGS). Four hot springs, Ojo Caliente, Azure, Frying
Pan, and Angel Terrace, were studied in detail. Analyses were performed adjacent to the sampling
site or in an on-site mobile lab truck constructed by the USGS, or later in a USGS laboratory.
Water temperature, specific conductance, pH, Eh, D.O., and dissolved H2S were determined
adjacent to the sample source at the time of sampling. Alkalinity and F- were determined on-site on
the day of sample collection. Thiosulfate and polythionates were determined as soon as possible
(minutes to hours later) by ion chromatography (IC). Other major anions (Cl-, SO4
2-, Br-) also were
determined on-site by IC within two days of sample collection. Ammonium, Fe(II), and Fe(total)
were determined on-site by ultraviolet/visible spectrophotometry within two days of sample
collection. Later in the USGS laboratory, densities were determined. Concentrations of Ca, Mg,
Li, Na, and K were determined by flame atomic absorption and emission (Na, K) spectrometry.
Concentrations of Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe(total), K, Mg, Mn, Na, Ni, Pb, Si, Sr,
V, and Zn were determined by inductively-coupled plasma optical emission spectrometry. Trace
concentrations of Al and Mg were determined by Zeeman-corrected graphite furnace atomic
absorption spectrometry.
Three important conclusions from the sampling and analyses are: (1) variability in H2S
concentrations can be caused as much by sampling and preservation artifacts as by actual variations
in water composition over time, (2) historical determinations of S2O3
2- were subject to
overestimation, most likely because of inadequate preservation leading to H2S oxidation, and (3)
S2O3
2- is a common constituent of hot spring waters.