Elemental partitioning between aqueous and solid phases of mercury and other constituents associated with Marcellus Shale Energy and Environment Laboratory (MSEEL) gas well production waste water, Morgantown, WV, 2015 - 2018.

The Marcellus Shale Energy and Environment Laboratory (MSEEL) site is a long-term field site and laboratory at the Northeast Natural Energy LLC (NNE) production facility, adjacent to the Monongahela River, located in western Monongalia County, West Virginia, USA. NNE began drilling two horizontal production wells, MIP (Morgantown Industrial Park) -5H and MIP-3H, in the Marcellus Shale in 2014. The wells were completed in December 2015. Large volumes of wastewater are generated with natural gas production. These wastewaters contain organic and inorganic chemical constituents from fracturing fluids used during drilling and stimulation of gas in host rocks/shale, as well as chemical compounds that are derived from formation water and the solid shale. Many of the organic and inorganic substances in the wastewater are potentially toxic and could pose an environmental risk if released due to spills, leaks, or unsafe disposal practices. Hydraulic fracturing fluid, field blanks, wastewater, and water from the Monongahela River stored in a lined holding pond adjacent to the MIP well pad, were collected by the U.S. Geological Survey (USGS) from November 2015 through April 2019. The on-site storage tank was sampled from April 2017 through April 2019. Wastewater from the MIP-5H Separator Tank was collected daily at the beginning of the study to annually by the end of the study. One sample was collected from the MIP-3H Separator Tank in May 2018. The data associated with the chemical conditions of the storage and separator tanks, at the time of sampling, have been previously published in a companion data release (https://doi.org/10.5066/P9Q3Y16S).

The current data release reports on a sub-set of production water samples co-collected from the abovementioned storage and separator tanks during the 2016-2018 period, which were reserved for explicit experiments and analyses associated with detailed geochemical characterization of both the solid phase and dissolved fractions. The eight machine readable data files (*.csv format) provided herein, and the description of the data contained in each, is as follows: a) T01_Particulates.csv, describes the solid-phase particulate fraction chemistry of 15 raw production water samples with respect to the particulate concentration (by dry mass and by volume), the percentage carbon and percentage nitrogen content, the concentration of 21 elements (aluminum, boron, barium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, nickel, phosphorous, potassium, silicon, sodium, strontium, sulfur, uranium, and zinc), and the concentration of two forms of mercury (total mercury and inorganic reactive mercury); b) T02_Filtered_Water.csv, describes the geochemical composition of the filter-passing fraction of 15 raw production water samples with respect to pH, density, alkalinity, dissolved inorganic carbon and dissolved organic carbon concentrations (both with 13C isotopic composition), ferrous iron, major anions (bromine, chlorine, sulfate), low molecular weight organic acids (acetate, butyrate, formate, and propionate), and 25 elements (aluminum, arsenic, boron, barium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, mercury, nickel, phosphorous, potassium, silicon, sodium, strontium, sulfur, tellurium, uranium, vanadium, and zinc); c) T03_Hg_Kd.csv, describes the calculated portioning coefficient (Kd) values for mercury (Hg) between the filter-passing and particulate phases in 13 of the raw production water samples; d) T04_HFO.csv, describes the elemental composition (28 analytes) in both the precipitate and the filtrate fractions of a synthetic hydrous ferric oxide (HFO) solution prepared to mimic and investigate the geochemical conditions that led to HFO formation in the original (field collected) production water samples; e) T05_BET.csv, describes the results of the Brunauer, Emmett, and Teller (BET) surface area determination of the solid particulates in a sub-set of the original production water samples and in the synthetic HFO; f) T06_XRD.csv, describes the X-ray diffraction (XRD) results (raw counts) used to determine the solid-phase mineral composition of the synthetic HFO and in 11 of the original production water samples; g) T07_Metals_Solid_Extractions, describes the elemental concentration results for solid-phase EDTA extraction experiments associated with the synthetic HFO and 11 of the original production water samples; h) T08_Oxidation_Exp.csv, describes the analytical results from an oxidation experiment conducted on a single raw production water sample (collected and initially stored anoxically) designed to examine the changes in total suspended solids, dissolved ferrous iron, particulate total mercury, filter-passing total mercury and calculated total mercury partitioning (between the solid and filter-passing phases) over a 48-hour time course after exposure of the sample to air; i) T09_Jug_Leachate.csv, describes the elemental composition (27 elements: aluminum, arsenic, boron, barium, calcium, cadmium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, nickel, phosphorous, potassium, silicon, selenium, sodium, strontium, sulfur, thallium, uranium, vanadium, and zinc) of acid-extractetions of precipitates that coated sample-collection jugs removing as much of the raw sample as possible and rinsing with MilliQ water to remove salts for 17 produced water samples; j) T10_EEMs.csv, optical fluorescence intensities associated with excitation-emission matrix spectra (EEMs) run on the filter-passing phase from three produced water samples; and k) T11_Sensor_Arrays.csv, summarizes the collective fluorescence intensity of common field sensors, measured as the sum of individual intensities for the wavelengths in the EEM spectra that are bracketed by the various field sensor arrays. The results are reported either in Raman normalized units from the Aqualog or are standardized to the fluorescence of known solutions across the same sensor arrays (see Booth and others, 2023).