Filters: Tags: Geochemistry (X)2,190 results (265ms)
Geochemistry has contributed significantly to the understanding of ground-water systems over the last 50 years. Historic advances include development of the hydrochemical facies concept, application of equilibrium theory, investigation of redox processes, and radiocarbon dating. Other hydrochemical concepts, tools, and techniques have helped elucidate mechanisms of flow and transport in ground-water systems, and have helped unlock an archive of paleoenvironmental information. Hydrochemical and isotopic information can be used to interpret the origin and mode of ground-water recharge, refine estimates of time scales of recharge and ground-water flow, decipher reactive processes, provide paleohydrological information,...
The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer
We examined the chemical reactions influencing dissolved concentrations, speciation, and transport of naturally occurring arsenic (As) in a shallow, sand and gravel aquifer with distinct geochemical zones resulting from land disposal of dilute sewage effluent. The principal geochemical zones were: (1) the uncontaminated zone above the sewage plume [350 µM dissolved oxygen (DO), pH 5.9]; (2) the suboxic zone (5 µM DO, pH 6.2, elevated concentrations of sewage-derived phosphate and nitrate); and (3) the anoxic zone [dissolved iron(II) 100–300 µM, pH 6.5–6.9, elevated concentrations of sewage-derived phosphate]. Sediments are comprised of greater than 90% quartz but the surfaces of quartz and other mineral grains are...
This is a report of geochemical data from various media collected on Isle Royale, a large island in northeastern Lake Superior. Isle Royale became a national park in 1940 and was designated as a wilderness area in 1976.USGS sampling began in 1996 as part of a larger project on the Midcontinent Rift in the Lake Superior region. Data are given in nine Microsoft Excel spreadsheets. All the data are newly acquired by the USGS.
Field portable X-ray fluorescence data for Hinkley and Water Valleys, San Bernardino County, California
These data were collected using field portable (handheld) X-ray fluorescence (pXRF) equipped with a 4-watt Ta/Au X-ray tube. Samples of surficial alluvium, rock, and archived core material from existing auger- or sonic-drilled monitoring wells in Hinkley Valley and the adjoining Water Valley, 140 kilometers (km) northeast of Los Angeles, California, were measured as part of an investigation of naturally-occurring and anthropogenic hexavalent chromium, Cr(VI), concentrations in local groundwater. Surficial alluvium samples were collected from small stream channels draining distinct geologic units, or from previously mapped river deposits, and generally consisted of silt, sand, and granules to small pebbles. Twigs...
Species and geochemical characteristics of heavy metals in the sediments of Kangjiaxi River in the Shuikoushan Mine Area, China
Data on soil denitrification potential and physico-chemical characteristics of tidal freshwater forested wetlands in Virginia
Denitrification measurements and ecosystem attributes in hummock-hollow microtopography of tidal freshwater forested wetlands along longitudinal riverine positions (upper, middle, and lower tidal river sites, and nearby upstream nontidal forested floodplains) of the adjoining Pamunkey and Mattaponi Rivers, Virginia.
Samples were submitted for contract laboratory analysis as part of a study examining the occurrence of chromium and natural and anthropogenic hexavalent Chromium, Cr(VI) in groundwater. Data will be used to estimate naturally-occurring background Cr(VI) concentrations upgradient, near the plume margins, and downgradient from a mapped Cr(VI) contamination plume near Hinkley, CA (Izbicki and Groover, 2016). These Contract Lab results are part of the data release including grain-size distribution, photographic and associated chemical and mineral analysis data for 36 sediment core and alluvium samples as well as Scanning Electron Microscopy analysis on select grains from magnetic and heavy mineral separates collected...
Modern groundwater-quality, depth, and well-construction data for selected wells in the San Joaquin Valley, California, 1993-2015
Groundwater-quality data collected between 1993 and 2015 were compiled from the U.S. Geological Survey (USGS) National Water Information System (NWIS) database for 722 wells in the San Joaquin Valley (SJV). Groundwater-quality data retrieved included lab analyses of complete major ion data (calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate, alkalinity, bicarbonate, carbonate, silica, and TDS) for 613 samples, and an additional 109 samples with measured values of specific conductance. Most of these wells were sampled as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project or the USGS National Water Quality Assessment (NAWQA) Program. In addition...
X-ray diffraction trace analysis of solid phase samples collected from groundwater wells at a confined disposal facility in East Chicago, Indiana
The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE), conducted a study from June 2014 through November 2014 to identify the hydrologic, chemical and microbiologic processes affecting declining pump performance and frequent pump failure at a confined disposal facility (CDF) in East Chicago, Indiana. Solid phase samples were collected from monitoring and extraction wells from September to November 2014. Qualitative and quantitative x-ray diffraction (XRD) analyses were done on eight samples of pump scrapings collected from five extraction wells (EW-4C, EW-4D, EW-11D, EW-20D) and one monitoring well (MW-4B). The data set includes a comma-separated value (.csv) file of XRD...
Utilizing geochemical, hydrologic, and boron isotopic data to assess the success of a salinity and selenium remediation project, Upper Colorado River Basin, Utah.
Stream discharge and geochemical data were collected at two sites along lower Ashley Creek, Utah, from 1999 to 2003, to assess the success of a site specific salinity and Se remediation project. The remediation project involved the replacement of a leaking sewage lagoon system that was interacting with Mancos Shale and increasing the dissolved salinity and Se load in Ashley Creek. Regression modeling successfully simulated the mean daily dissolved salinity and Se loads (R(2) values ranging from 0.82 to 0.97) at both the upstream (AC1) and downstream (AC2/AC2A) sites during the study period. Prior to lagoon closure, net gain in dissolved-salinity load exceeded 2177 metric tons/month and decreased after remediation...
This dataset contains geochemical data for unconsolidated sediments (stream sediments, lake sediments, etc.) collected by U.S. Geological Survey (USGS) personnel and analyzed in the analytical laboratories of the Geologic Division of the USGS. These data represent analyses of sediment samples collected in support of various USGS programs. The data were originally entered into the in-house Rock Analysis Storage System (RASS) database which was used by the Geologic Division from the early-1970's through the late-1980's to archive geochemical data. An unpublished CD-ROM was developed in 1996 that contains the RASS data in GSSEARCH format. That CD was used to generate this data set.
Geochemical evidence of pollutants from coal-fired generating stations in late pleistocene palaeosols in the Dalijia Shan, northwestern China
Biogeochemical influences on the determination of water chemistry in a temperate forest basin: Factors determining the pH value