Firehole River near Madison Junction (YFIR), Yellowstone National Park Sample Collection: Samples were collected near the USGS stream gage 06036905 (Latitude 44°37'12.66", Longitude 110°51'48.61" NAD83). At the time of collection, all waters samples were filtered through a syringe filter (0.45-micrometer). Two splits of the filtered water were retained for chemical analyses, including an unacidified (FU) sample for determination of anion concentrations and a nitric acid preserved (FA; 1% volume-to-volume concentrated trace-metal grade nitric acid) sample for cation and trace metal analyses. During sample collection, the water temperature, specific conductance, and pH were often measured. Sample Analyses: Concentrations of chloride, fluoride, bromide, and sulfate were determined with an ion chromatograph (Dionex ICS-2000). Analytical errors for these constituents were typically less than 2%. Total alkalinity as bicarbonate was determined on stored samples, usually within several months after collection. Ten milliliters of sample were titrated with 0.05 Normal sulfuric acid to the bicarbonate end-point. The analytical error in alkalinity concentrations was roughly ± 5%. Concentrations of cations and trace metals were determined with an inductively coupled plasma-optical emission spectroscopy (Perkin Elmer Optima 7300 DV) following the methods described in Ball and others (2010). Database Contents The data file (YFIR.csv) contains the solute concentrations and the water discharge at the time of sampling for each of the rivers studied. The entries in the data file appear in the following columns: A. Date sample collected B. Time sample collected C. Water discharge (cubic feet per second) obtained from the U.S. Geological Survey's National Water Information System (NWIS) D. Water discharge (cubic meter per second) - obtained by multiplying column C by 0.02832 E. Chloride concentration (milligrams per liter) F. Fluoride concentration (milligrams per liter) G. Bromide concentration (milligrams per liter) H. Sulfate concentration (milligrams per liter) I. Alkalinity (milligrams per liter as bicarbonate) J. Chloride flux (grams/second) K. pH (standard units) L. Specific conductance (microSiemens per centimeter) M. Temperature (degrees Celsius) N. Calcium concentration (milligrams per liter) O. Magnesium concentration (milligrams per liter) P. Sodium concentration (milligrams per liter) Q. Potassium concentration (milligrams per liter) R. Iron concentration (milligrams per liter) S. Silica concentration (milligrams per liter) T. Boron concentration (milligrams per liter) U. Aluminum concentration (milligrams per liter) V. Lithium concentration (milligrams per liter) W. Strontium concentration (milligrams per liter) X. Barium concentration (milligrams per liter) Y. Rubidium concentration (milligrams per liter) Z. Manganese concentration (milligrams per liter) AA. Molybdenum concentration (milligrams per liter) AB. Copper concentration (milligrams per liter) AC. Zinc concentration (milligrams per liter) AD. Cadmium concentration (milligrams per liter) AE. Chromium concentration (milligrams per liter) AF. Cobalt concentration (milligrams per liter) AG. Lead concentration (milligrams per liter) AH. Nickel concentration (milligrams per liter) AI. Vanadium concentration (milligrams per liter) AJ. Arsenic concentration (milligrams per liter) AK. Antimony concentration (milligrams per liter) References Ball, J.W., McCleskey, R.B., and Nordstrom, D.K., 2010, Water-chemistry data for selected springs, geysers, and streams in Yellowstone National Park, Wyoming, 2006-2008: U.S. Geological Survey Open-File Report 2010-1192, 109 p.