Search USGS⌕ Search

SEARCH · Search USGS

Results for “Chemistry Select”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
USGS2008

Ground-water quality data in the San Fernando-San Gabriel study unit, 2005— Results from the California GAMA program

Ground-water quality in the approximately 460 square mile San Fernando-San Gabriel study unit (SFSG) was investigated between May and July 2005 as part of the Priority Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The San Fernando-San Gabriel study was designed to provide a spatially unbiased assessment of raw ground-water quality within SFSG, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 52 wells in Los Angeles County. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and seventeen wells were selected to aid in the evaluation of specific water-quality issues or changes in water chemistry along a historic ground-water flow path (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), 1,2,3-trichloropropane (1,2,3-TCP), and 1,4-dioxane], naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately one-fifth (11 of 52) of the wells, and the results for these samples were used to evaluate the quality of the data for the ground-water samples. Assessment of the quality-control results showed that the data had very little bias or variability and resulted in censoring of less than 0.7 percent (32 of 4,484 measurements) of the data collected for ground-water samples. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, or blended with other waters to maintain acceptable water quality. Regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. However, to provide some context for the results, concentrations of constituents measured in the raw ground water were compared with health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and California Department of Public Health (CDPH) and thresholds established for aesthetic concerns (secondary maximum contaminant levels, SMCL-CA) by CDPH. VOCs were detected in more than 90 percent (33 of 35) of grid wells. For all wells sampled for SFSG, nearly all VOC detections were below health-based thresholds, and most were less than one-tenth of the threshold values. Samples from seven wells had at least one detection of PCE, TCE, tetrachloromethane, NDMA, or 1,2,3-TCP at or above a health-based threshold. Pesticides were detected in about 90 percent (31 of 35) grid wells and all detections in samples from SFSG wells were below health-based thresholds. Major ions, trace elements, and nutrients in samples from 17 SFSG wells were all below health-based thresholds, with the exception of one detection of nitrate that was above the USEPA maximum contaminant level (MCL-US). With the exception of 14 samples having radon-222 above the proposed MCL-US, radioactive constituents were below health-based thresholds for 16 of the SFSG wells sampled. Total dissolved solids in 6 of the 24 SFSG wells that were sampled ha

California↗
USGS2009

Ecological assessment of wadeable streams on O`ahu, Hawai'i, 2006-2007: A pilot study

In 2006–07, the U.S. Geological Survey (USGS) Pacific Islands Water Science Center (PIWSC), in cooperation with the Hawai‘i Department of Health (HDOH), conducted a pilot study as a participant in the U.S. Environmental Protection Agency’s (USEPA) Wadeable Streams Assessment (WSA) program. Forty randomly selected sites on perennial streams on O‘ahu, Hawai‘i, were surveyed for habitat characteristics, water chemistry, and benthic macroinvertebrate assemblages. Of the original sampling frame of approximately 505.2 miles of perennial stream, roughly 96.7±30.7 miles were found to be nonperennial or estuarine and another 200.5±64.7 miles were judged to be inaccessible. The scope of this report presents an assessment of the remaining 208±57.6 miles of accessible, wadeable, perennial stream length on O‘ahu. Benthic macroinvertebrate assemblages were used to determine the ecological condition at each site. Components of the benthic macroinvertebrate assemblages were assessed using the multimetric Preliminary–Hawaiian Benthic Index of Biotic Integrity (P–HBIBI) developed by Wolff (2005). Based on the P–HBIBI scores, an estimated 5.8±5.8 percent of the island’s total stream length is in most disturbed condition, 56±13.5 percent is in intermediately disturbed condition, and 38.2±13.2 percent is in least disturbed condition. Windward O‘ahu had the highest percentage of stream length in least disturbed biological condition at 56.7±20.8 percent. Using the relative abundance of insects, one of the core metrics that make up the P–HBIBI, 43.4±14.2 percent of the islandwide stream length was classified in the most disturbed condition—52±31.2 percent of the Honolulu region stream length and 51.4±23.3 percent of the windward O‘ahu stream length. An analysis of total nitrogen (N) estimated approximately 41.1±13.7 percent of the stream length on O‘ahu was in most disturbed condition. Regionally, the Honolulu region had the largest proportion, 61.3±28.6 percent, of most disturbed stream length in terms of total N. An analysis of total phosphorus (P) classified approximately 43.2±14 percent of the stream length on O‘ahu as most disturbed. Regionally, windward O‘ahu had the largest proportion, 78.4±19.5 percent, of stream length classified as most disturbed. An analysis of embeddedness classified 30.3±14.7 percent of O‘ahu’s stream length as most. Regionally, windward O‘ahu had the largest proportion, 43.3±17.1 percent, of stream length classified as most disturbed as compared to the reference condition. An analysis of riparian disturbance, an index of the in-channel, riparian, and near-stream human activities, classified 43±13 percent of stream length on O‘ahu as most disturbed. The Honolulu region had the largest proportion of stream length, 86.3±13.7 percent, classified as most disturbed. The information in this report is the first attempt in Hawai‘i to assess the islandwide ecological condition of wadeable, perennial streams on O‘ahu using the USEPA WSA probabilistic design. This study has demonstrated that such an assessment is practical and that it can provide information that may help the USEPA and HDOH in determining the status of aquatic ecosystems on O‘ahu, Hawai‘i. This study provides a baseline assessment of the current islandwide ecological condition and identifies potential environmental stressors. It can be used, with future WSA studies in Hawai‘i, to measure the changes in those conditions and the effectiveness of management efforts to protect, restore, and maintain Hawai‘i’s aquatic environment.

Hawaii↗
USGS2015

Groundwater chemistry in the vicinity of the Puna Geothermal Venture Power Plant, Hawai‘i, after two decades of production

We report chemical data for selected shallow wells and coastal springs that were sampled in 2014 to determine whether geothermal power production in the Puna area over the past two decades has affected the characteristics of regional groundwater. The samples were analyzed for major and minor chemical species, trace metals of environmental concern, stable isotopes of water, and two organic compounds (pentane and isopropanol) that are injected into the deep geothermal reservoir at the power plant. Isopropanol was not detected in any of the groundwaters; confirmed detection of pentane was restricted to one monitoring well near the power plant at a low concentration not indicative of source. Thus, neither organic compound linked geothermal operations to groundwater contamination, though chemical stability and transport velocity questions exist for both tracers. Based on our chemical analysis of geothermal fluid at the power plant and on many similar results from commercially analyzed samples, we could not show that geothermal constituents in the groundwaters we sampled came from the commercially developed reservoir. Our data are consistent with a long-held view that heat moves by conduction from the geothermal reservoir into shallow groundwaters through a zone of low permeability rock that blocks passage of geothermal water. The data do not rule out all impacts of geothermal production on groundwater. Removal of heat during production, for example, may be responsible for minor changes that have occurred in some groundwater over time, such as the decline in temperature of one monitoring well near the power plant. Such indirect impacts are much harder to assess, but point out the need for an ongoing groundwater monitoring program that should include the coastal springs down-gradient from the power plant.

Hawaii↗
USGS2003

Assessment of selected inorganic constituents in streams in the Central Arizona Basins study area, Arizona and northern Mexico, through 1998

Stream properties and water-chemistry constituent concentrations from data collected by the National Water-Quality Assessment and other U.S. Geological Survey water-quality programs were analyzed to (1) assess water quality, (2) determine natural and human factors affecting water quality, and (3) compute stream loads for the surface-water resources in the Central Arizona Basins study area. Stream temperature, pH, dissolved-oxygen concentration and percent saturation, and dissolved-solids, suspended-sediment, and nutrient concentration data collected at 41 stream-water quality monitoring stations through water year 1998 were used in this assessment. Water-quality standards applicable to the stream properties and water-chemistry constituent concentration data for the stations investigated in this study generally were met, although there were some exceedences. In a few samples from the White River, the Black River, and the Salt River below Stewart Mountain Dam, the pH in reaches designated as a domestic drinking water source was higher than the State of Arizona standard. More than half of the samples from the Salt River below Stewart Mountain Dam and almost all of the samples from the stations on the Central Arizona Project Canal—two of the three most important surface-water sources used for drinking water in the Central Arizona Basins study area—exceeded the U.S. Environmental Protection Agency drinking water Secondary Maximum Contaminant Level for dissolved solids. Two reach-specific standards for nutrients established by the State of Arizona were exceeded many times: (1) the annual mean concentration of total phosphorus was exceeded during several years at stations on the main stems of the Salt and Verde Rivers, and (2) the annual mean concentration of total nitrogen was exceeded during several years at the Salt River near Roosevelt and at the Salt River below Stewart Mountain Dam. Stream properties and water-chemistry constituent concentrations were related to streamflow, season, water management, stream permanence, and land and water use. Dissolved-oxygen percent saturation, pH, and nutrient concentrations were dependent on stream regulation, stream permanence, and upstream disposal of wastewater. Seasonality and correlation with streamflow were dependant on stream regulation, stream permanence, and upstream disposal of wastewater. Temporal trends in streamflow, stream properties, and water-chemistry constituent concentrations were common in streams in the Central Arizona Basins study area. Temporal trends in the streamflow of unregulated perennial reaches in the Central Highlands tended to be higher from 1900 through the 1930s, lower from the 1940s through the 1970s, and high again after the 1970s. This is similar to the pattern observed for the mean annual precipitation for the Southwestern United States and indicates long-term trends in flow of streams draining the Central Highlands were driven by long-term trends in climate. Streamflow increased over the period of record at stations on effluent-dependent reaches as a result of the increase in the urban population and associated wastewater returns to the Salt and Gila Rivers in the Phoenix metropolitan area and the Santa Cruz River in the Tucson metropolitan area. Concentrations of dissolved solids decreased in the Salt River below Stewart Mountain Dam and in the Verde River below Bartlett Dam. This decrease represents an improvement in the water quality and resulted from a concurrent increase in the amount of runoff entering the reservoirs. Stream loads of water-chemistry constituents were compared at different locations along the streams with one another, and stream loads were compared to upstream inputs of the constituent from natural and anthropogenic sources to determine the relative importance of different sources and to determine the fate of the water-chemistry constituent. Of the dissolved solids transported into the Basin and Range Lowlands each year from the Central Arizona Project Canal and from streams draining the Central Highlands, about 1.2 billion kilograms accumulated in the soil, unsaturated zone, and aquifers in agricultural and urban areas as a result of irrigating crops and urban vegetation. Stream loads of phosphorus decreased from the 91st Avenue Wastewater-Treatment Plant downstream to the Gila River at Gillespie Dam, probably as a result of adsorption of phosphorus to the streambed sediments. In this same reach, stream loads of nitrogen increased, most likely because of inputs from fertilizers. The annual mass of nitrogen and phosphorus input to developed basins from quantifiable sources was much larger than the mass input to basins that had little or no municipal or agricul-tural development. These computed inputs exclude the mass of nitrogen and phosphorus from sources such as geologic formations and soils that could not be quantified. The quantifiable annual inputs of nitrogen and phosphorus for the upper Salt River Basin and the upper Verde River Basin were similar to those for the West Clear Creek Basin. This similarity suggests that the small amount of municipal and agricultural development in the upper Salt River and the upper Verde River Basins did not greatly change the basin input flux. For basins with minimal urban and agricultural development, the largest quantifiable source of nitrogen was precipitation, and the largest source of phosphorus was human bodily waste treated by sewer and septic systems. This was in contrast to developed basins, for which fertilizer was the largest quantifiable source of both nutrients. For most basins examined, quantifiable inputs of nitrogen and phosphorus from nonpoint sources were greater than inputs from point sources. This relation emphasizes the importance of land- and water-management policies that protect surface-water resources from nonpoint sources of nutrients as well as from point sources. The amount of nitrogen and phosphorus transpor-ted out of basins was a small fraction of the total for the quantifiable inputs. This result indicated that most of the nutrients input to basins were not transported out of the basins in surface water, but rather were transported to the subsurface (the soil, unsaturated zone, or aquifer), released to the atmosphere (such as volatilized ammonia), or incorporated into the biomass.

Central Arizona Basins study area↗
USGS2005

Effects of emission reductions at the Hayden powerplant on precipitation, snowpack, and surface-water chemistry in the Mount Zirkel Wilderness Area, Colorado, 1995-2003

Precipitation, snowpack, and surface-water samples collected during 1995-2003 were analyzed to evaluate the effects of emission reductions at the Hayden powerplant on water chemistry in the Mount Zirkel Wilderness Area. The Hayden powerplant, one of two large coal-fired powerplants in the Yampa Valley, was retrofitted with control systems during late 1998 and 1999 to reduce emissions of sulfur dioxide and nitrogen oxide--the primary precursors of haze and acidic precipitation. The U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, evaluated three water-chemistry data sets: wet-only precipitation chemistry from the National Atmospheric Deposition Program, snowpack chemistry from the Rocky Mountain snowpack network, and surface-water chemistry from a U.S. Geological Survey long-term lakes monitoring program. Concentrations and deposition rates of selected constituents were compared for the periods before and after emission reductions at the Hayden powerplant. Data collected during 1995-98 were used to represent the pre-control period, and data collected during 2000-2003 were used to represent the post-control period. Ten stations in the National Atmospheric Deposition Program were evaluated including two that were directly downwind from the Hayden powerplant (Dry Lake and Buffalo Pass) and eight that were upwind or more distant (more than 100 kilometers) from the powerplant. Precipitation amount at all 10 precipitation stations was lower in the post-control period than the pre-control period as a result of a regional drought that persisted during the post-control period. In contrast to precipitation amount, there was no consistent pattern of change in sulfate concentrations between periods, indicating that the drought did not have a concentrating effect on sulfate or that trends in regional sulfur dioxide emissions masked its influence. Sulfate concentrations increased at three stations between periods, remained the same at three stations, and decreased at four stations. The largest change in average annual sulfate concentrations occurred at the two precipitation stations downwind from the Hayden powerplant, decreasing by 3.3 microequivalents per liter at Dry Lake and by 2.2 microequivalents per liter at Buffalo Pass. Declines in annual sulfate deposition also were greater at Dry Lake (3.4 kilograms per hectare) and Buffalo Pass (3.3 kilograms per hectare) than at the other stations, which ranged from 0.2 to 1.7 kilograms per hectare. These results indicate that emission reductions at the Hayden powerplant have been a factor in declines in atmospheric deposition of sulfate downwind from the powerplant. Nitrate, ammonium, and base-cation concentrations, in contrast to sulfate, were higher in the post-control period than the pre-control period at all 10 stations, most likely due to a concentrating effect of the drought. Twenty-two snowpack sites in the Rocky Mountain snowpack network were evaluated including 4 sites that were located directly downwind from the Hayden powerplant and 18 sites that were upwind or more distant (as much as 200 kilometers) from the powerplant. The water content of the snowpack at maximum accumulation was lower in the post-control period than the pre-control period, reflecting the regional drought. Although there were small declines in snowpack sulfate concentrations at the downwind stations between the pre- and post-control periods, the difference was not statistically significant, indicating emission reductions had a weaker effect on snowpack chemistry than precipitation chemistry. Sulfate deposition decreased at all four downwind sites in the post-control period, primarily reflecting both lower water content and concentrations in the snowpack. As observed at the precipitation stations, nitrate, ammonium, and base-cation concentrations at all 22 sites were significantly higher in the post-control period than the pre-control period, reflecting drier conditions caused by drought. The chemistry at six surface-water sites in and near the Mount Zirkel Wilderness Area and five control sites in the Flat Tops Wilderness Area was examined. No response to emission reductions was detectable in chemistry of the surface water in the Mount Zirkel Wilderness Area. Detection of a response to changes in emissions and deposition in the lake-chemistry data may have been confounded by drought conditions during the period after emission reductions occurred. The magnitude of reduced sulfate in atmospheric deposition indicates that at some time in the future, a reduction in lake sulfate attributable to Yampa Valley emission reduction should be detectable. The trend of decreasing sulfur dioxide emissions throughout western North America over the past 20 years is reflected in reduced concentrations of sulfate in lakes that were part of this study, as well as other lakes in the Rocky Mountains. However, detection of the surface-water response to changes in deposition requires a sufficiently long record to minimize effects of climate variability and to allow for lag time as sulfate moves through storage in soil, ground water, and lake reservoirs.

Colorado↗
USGS2005

Questa baseline and pre-mining ground-water quality investigation. 14. Interpretation of ground-water geochemistry in catchments other than the Straight Creek catchment, Red River Valley, Taos County, New Mexico, 2002-2003

The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site but proximal analog. The Straight Creek catchment, chosen for this purpose, consists of the same Tertiary-age quartz-sericite-pyrite altered andesite and rhyolitic volcanics as the mine site. Straight Creek is about 5 kilometers east of the eastern boundary of the mine site. Both Straight Creek and the mine site are at approximately the same altitude, face south, and have the same climatic conditions. Thirteen wells in the proximal analog drainage catchment were sampled for ground-water chemistry. Eleven wells were installed for this study and two existing wells at the Advanced Waste-Water Treatment (AWWT) facility were included in this study. Eight wells were sampled outside the Straight Creek catchment: one each in the Hansen, Hottentot, and La Bobita debris fans, four in a well cluster in upper Capulin Canyon (three in alluvial deposits and one in bedrock), and an existing well at the U.S. Forest Service Questa Ranger Station in Red River alluvial deposits. Two surface waters from the Hansen Creek catchment and two from the Hottentot drainage catchment also were sampled for comparison to ground-water compositions. In this report, these samples are evaluated to determine if the geochemical interpretations from the Straight Creek ground-water geochemistry could be extended to other ground waters in the Red River Valley , including the mine site. Total-recoverable major cations and trace metals and dissolved major cations, selected trace metals, anions, alkalinity; and iron-redox species were determined for all surface- and ground-water samples. Rare-earth elements and low-level As, Bi, Mo, Rb, Re, Sb, Se, Te, Th, U, Tl, V, W, Y, and Zr were determined on selected samples. Dissolved organic carbon (DOC), mercury, sulfate stable isotope composition (δ 34 S and δ 18 O of sulfate), stable isotope composition of water (δ 2 H and δ 18 O of water) were measured for selected samples. Chlorofluorocarbons (CFC) and 3 He and 3 H were measured for age dating on selected samples. Linear regressions from the Straight Creek ground-water data were used to compare ground-water chemistry trends in non-Straight Creek ground waters with Straight Creek alluvial ground-water chemistry dilution trends. Most of the solute trends for the ground waters are similar to those for Straight Creek but there are some notable exceptions. In lithologies that contain substantial pyrite mineralization, acid waters form with similar chemistries to those in Straight Creek and all the waters tend to be calcium-sulfate type. Hottentot ground waters contain substantially lower calcium concentrations relative to those in Straight Creek. This anomaly results from the exposure of rhyolite porphyry in the Hottentot scar and weathering zone. The rhyolite contains less calcium than the altered andesites and tuffs in the Straight Creek catchment and probably does not have the abundant gypsum and calcite. The Hansen ground waters have reached gypsum saturation and have similar calcium, magnesium, and beryllium concentrations as Straight Creek ground waters but have lower concentrations of fluoride, manganese, zinc, cobalt, nickel, copper, and lithium. Lower concentrations of elements related to mineralization at Hansen likely reflect the more distal location of Hansen with respect to intrusive centers that provided the heat source for hydrothermal alteration. The other ground water with water chemistry trends that are outside the Straight Creek trends was from an alluvial well from Capulin Canyon (CC2A). Although it had pH values near 6.0 and most major ions similar to the other Capulin Canyon ground waters, it contained high concentrations of fluoride, manganese, aluminum, iron, beryllium, and zinc similar to a mineralized zone and had low alkalinity. Saturation indices indicate that solubility constraints continue to provide upper limits on some solute concentrations. Siderite, ferrihydrite, calcite, gypsum, rhodochrosite, and barite provide limits for concentrations of Fe(II), Fe(III), Ca, Mn, and Ba, respectively. Beryllium concentrations may be subject to an upper concentration limit by the solubility of Be(OH) 2 but these concentrations probably are not reached in the ground waters. Ground-water isotopic data were consistent with the meteoric water line estimated for precipitation in the Red River Valley, indicating that all the ground waters examined in this study were meteoric, recent in origin, and showed no substantial indication of evaporation. Tritium-helium-3 and chlorofluorocarbon (CFC) age dating were partially successful. Generally, dates were consistent with location and depth of wells. Two samples had good agreement between CFC dates and tritium-helium dates, whereas a third reflected either substantial mixing with younger or older waters or complications arising from excess helium-4. The well at La Bobita appeared to contain a large component of modern water, most likely as a result of mixing with water from Red River alluvial deposits.

New Mexico↗
USGS2012

National hydrography dataset--linear referencing

Geospatial data normally have a certain set of standard attributes, such as an identification number, the type of feature, and name of the feature. These standard attributes are typically embedded into the default attribute table, which is directly linked to the geospatial features. However, it is impractical to embed too much information because it can create a complex, inflexible, and hard to maintain geospatial dataset. Many scientists prefer to create a modular, or relational, data design where the information about the features is stored and maintained separately, then linked to the geospatial data. For example, information about the water chemistry of a lake can be maintained in a separate file and linked to the lake. A Geographic Information System (GIS) can then relate the water chemistry to the lake and analyze it as one piece of information. For example, the GIS can select all lakes more than 50 acres, with turbidity greater than 1.5 milligrams per liter.

Fact Sheet↗
USGS2014

Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

Fossil fuels from the Appalachian basin region have been major contributors to the Nation’s energy supplies over much of the last three centuries. Appalachian coal and petroleum resources are still available in sufficient quantities to contribute significantly to fulfilling the Nation’s energy needs. Although both conventional oil and gas continue to be produced in the Appalachian basin, most new wells in the region are drilled in shale reservoirs to produce natural gas. U.S. Geological Survey (USGS) Professional Paper 1708 is a modern, indepth collection of reports, cross sections, and maps that describe the geology of the Appalachian basin and its fossil fuel resources. This publication supplements and updates older USGS regional studies of Appalachian basin coal and petroleum resources. Some chapters are new, and several have been published in outside journals or as other USGS publications. Although this volume is not a comprehensive regional treatment of all notable geologic and fossil fuel localities in the Appalachian basin, the selected study areas and topics presented in the chapters pertain to large segments of the basin and a wide range of stratigraphic intervals. This volume discusses the locations of coal and petroleum accumulations, the stratigraphic and structural framework, and the geochemical characteristics of the coal beds and petroleum in the basin, as well as the results of recent USGS assessments of coal, oil, and gas resources in the basin. Many of the maps and accompanying data supporting the reports in this volume are available from chapter I.1 as downloadable geographic information system (GIS) data files about the characteristics of selected coal beds and oil and gas fields, locations of oil and gas wells, coal production, coal chemistry, total petroleum system (TPS) boundaries, and bedrock geology. Log ASCII Standard (LAS) files for geophysical (gamma ray) wireline well logs are included in other chapters. Professional Paper 1708 is intended primarily for geoscientists in academia, industry, and government who are interested in Appalachian basin geology and its coal and petroleum resources. Other users, however, may find the topics, papers, and digital images valuable for land-use and policy planning. Among the anticipated benefits of the report are improvements in (1) resource assessment estimates and methodology, (2) exploration strategies, (3) basin models, and (4) energy use policies.

Appalachian basin↗
USGS2009

Characterization of Groundwater Quality Based on Regional Geologic Setting in the Piedmont and Blue Ridge Physiographic Provinces, North Carolina

A compilation of groundwater-quality data collected as part of two U.S. Geological Survey studies provides a basis for understanding the ambient geochemistry related to geologic setting in the Piedmont and Blue Ridge Physiographic Provinces (hereafter referred to as Piedmont and Mountains Provinces) of North Carolina. Although the geology is complex, a grouping of the sampled wells into assemblages of geologic units described as 'geozones' provides a basis for comparison across the region. Analyses of these two data sets provide a description of water-quality conditions in bedrock aquifers of the Piedmont and Mountains Provinces of North Carolina. Analyzed data were collected between 1997 and 2008 from a network of 79 wells representing 8 regional geozones distributed throughout the Piedmont and Mountains Provinces. This area has experienced high rates of population growth and an increased demand for water resources. Groundwater was used by about 34 percent of the population in the 65 counties of this region in 2005. An improved understanding of the quality and quantity of available groundwater resources is needed to plan effectively for future growth and development. The use of regional geologic setting to characterize groundwater-quality conditions in the Piedmont and Mountains Provinces is the focus of this investigation. Data evaluation included an examination of selected properties and the ionic composition of groundwater in the geozones. No major differences in overall ionic chemistry of groundwater among the geozones were evident with the data examined. Variability in the cationic and anionic composition of groundwater within a particular geozone appeared to reflect local differences in lithologic setting, hydrologic and geochemical conditions, and(or) land-use effects. The most common exceedances of the drinking-water criteria (in accordance with Federal and State water-quality standards) occurred for radon, pH, manganese, iron, and zinc. Radon had the most exceedances, with groundwater from 61 of the 69 sampled wells having activities higher than the U.S. Environmental Protection Agency's proposed maximum contaminant level of 300 picocuries per liter. Overall, the Milton and the Raleigh and Charlotte geozones had the greatest number, eight each, of water-quality properties or constituents that exceeded applicable drinking-water criteria in at least one well. The Eastern Blue Ridge and Felsic intrusive geozones each had seven properties or constituents that exceeded criteria, and the Carolina slate geozone had six. Based on limited data, initial results of statistical comparison tests identified statistically significant differences in concentrations of some groundwater constituents among the geozones. Statistically significant differences in median values of specific conductance and median concentrations of calcium, potassium, sodium, bicarbonate, chloride, silica, ammonia, aluminum, antimony, cadmium, and uranium were identified between one or more geozone pairs. Overall, the groundwater constituents appear to be influenced most significantly by the Inner Piedmont, Carolina slate, and Felsic intrusive geozones. The study data indicate that grouping and evaluating analytical data on the basis of regional geozone setting can be useful for characterizing water-quality conditions in bedrock aquifers of the Piedmont and Blue Ridge Provinces of North Carolina.

North Carolina↗
USGS1998

Comparison of NPDES program findings for selected cities in the United States

The U.S. Environmental Protection Agency, under section 402 (p) of the Water Quality Act of 1987, has required municipalities with populations of more than 100,000 to obtain National Pollutant Discharge Elimination System (NPDES) permits for urban stormwater discharge. This regulation is intended to minimize pollutant loadings from urbanized areas and preserve the quality of streams that receive stormwater. To apply for a NPDES permit, a municipality must monitor the chemistry of stormwater from basins having residential, commercial, and industrial land uses, and estimate storm- and annual pollutant loads and event-mean concentrations of 12 selected properties and constituents. The properties and constituents include biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids, dissolved solids, total nitrogen, total ammonia plus organic nitrogen, total phosphorus, dissolved phosphorus, total recoverable cadmium, total recoverable copper, total recoverable lead, and total recoverable zinc. These estimates will be used by the municipalities to evaluate the magnitude of pollutant loadings and the ef ficiency of management strategies that are intended to reduce pollutant loads. As part of a national synthesis of the study units in the U.S. Geological Survey (USGS) NPDES program, data were compiled on concentrations of the 12 properties and constituents required for load calculations. This report presents a comparison of these data.

Fact Sheet↗
USGS2002

Elemental chemistry of streambed sediments of the St. Croix River Basin, 2000

Streambed sediments from 30 sites in the St. Croix River Basin were analyzed for selected chemical elements. Possible occurrences of low-level contamination include: (1) elevated concentrations of arsenic, lead, silver, and to a lesser extent cadmium, copper, and mercury in the Namekagon River downstream of Hayward, Wisconsin; (2) elevated lead concentrations in the St. Croix River downstream of the Stillwater, Minnesota—Hudson, Wisconsin region; (3) slightly elevated concentrations of Arsenic, Cadmium, Copper, Lead, Mercury, Silver, Vanadium, and Zinc in the Kettle River downstream of Sandstone and Hinckley, Minnesota; (4) and substantially elevated mercury concentrations in Rush Creek downstream of Rush City, Minnesota. Elevated concentrations of copper, lead, and to a lesser extent cadmium, in Osceola Creek, downstream of Osceola, Wisconsin may be due to anthropogenic sources or contributions from bedrock that differs geochemically from sediments farther upstream. There does not appear to be large anthropogenic contributions of trace elements—above the background geochemical and atmospherically deposited levels—in the streams sampled for this study. Many of the elements appear to be associated with mineral sources. Concentrations of potentially toxic trace elements in the St. Croix River Basin generally were lower than concentrations associated with frequent adverse effects to aquatic biota. Exceptions were arsenic (7 of 30 samples) and mercury (1 of 30 samples).

Minnesota, Wisconsin↗
USGS2007

Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005

The Milwaukee Metropolitan Sewerage District (MMSD) Corridor Study is a three-phase project designed to improve the understanding of water resources in the MMSD planning area to assist managers and policy makers in their decisions. Phase I of the Study involved the compilation of existing data from multiple agencies into a single database. These data were analyzed to identify spatial, temporal, and technological gaps in the planning area, and were used to develop Phase II of the Study. Phase II, the subject of this report, involved an intensive data-collection effort by the U.S. Geological Survey (USGS) in cooperation with MMSD (from February, 2004, through September, 2005). This phase addressed the data gaps identified in Phase I and completed a baseline assessment of water quality for selected stream and harbor sites in the MMSD planning area. This baseline assessment included evaluations of surface-water chemistry and microbial concentrations in the streams and harbor sites; additionally, stream sites were evaluated for discharge, sediment chemistry, fish-tissue chemistry, habitat, and the quality of biological communities (including fish, macroinvertebrates, and algae). In all, data were collected at 15 stream and 6 harbor sites within the MMSD planning area, including manual sampling and analysis for more than 220 water-quality properties and constituents at all 21 sites, stream-discharge data for 14 stream sites, and automated water-quality sampling at 4 stream sites. A bioassessment during autumn 2004 included collection of biologic-community data and stream-habitat data at wadeable streams. Quartiles of Phase II aggregate bioassessment rankings were used to divide the 14 wadeable stream sites into four groups to investigate relations between bioassessment data and site characteristic and water-quality data. Quartile numbers reflect relative water quality: quartile 1 contained sites where the bioassessment data indicated the least-degraded water quality among those sampled, and quartile 4 contained sites that indicated the most-degraded water quality. Quartiles contained the following stream sites: Quartile 1: Milwaukee River near Cedarburg, Milwaukee River at Milwaukee, Jewel Creek, and Menomonee River at Menomonee Falls; Quartile 2: Willow Creek, Root River near Franklin, and Root River at Grange Avenue; Quartile 3: Menomonee River at Wauwatosa, Oak Creek, and Little Menomonee River; and Quartile 4: Honey Creek, Underwood Creek, Lincoln Creek, and Kinnickinnic River. Site characteristics (in this case, drainage area and land use) and selected water-quality data were summarized based on the four bioassessment quartiles to determine if there were relations with the aggregate bioassessment rankings. In general, sites having the largest drainage basins with the lowest proportion of urban land use were in quartile 1, and the smallest drainage basins with the highest proportion of urban land use were in quartile 4. Major ions, indicator organisms, and wastewater compounds generally had the lowest overall results in quartile 1 and highest overall results in quartile 4, with intermediate results in quartiles 2 and 3. Results for other constituent types (nutrients, mercury, pathogenic organisms, and bed sediment) were mixed, with results for some constituents decreasing from quartile 1 to quartile 4. Where sufficient Phase I data were available, summary statistics (including medians) for chemical and biological data were calculated, allowing some comparisons to be made between Phase I and Phase II data. Comparisons between Phase I and Phase II results indicated a variety of changes with respect to water quality. Concentrations of chloride, nitrate, chlorophyll a, total phosphorus in water; arsenic in bed sediment; and fish Index of Biotic Integrity ratings generally indicated declines in water quality. However, concentrations of total nitrogen, suspended sediment, and fecal coliform in water; some trace eleme

Wisconsin↗
USGS2018

Impact of pore fluid chemistry on fine-grained sediment fabric and compressibility

Fines, defined here as grains or particles, less than 75 μm in diameter, exist nearly ubiquitously in natural sediment, even those classified as coarse. Macroscopic sediment properties, such as compressibility, which relates applied effective stress to the resulting sediment deformation, depend on the fabric of fines. Unlike coarse grains, fines have sizes and masses small enough to be more strongly influenced by electrical interparticle forces than by gravity. These electrical forces acting through pore fluids are influenced by pore fluid chemistry changes. Macroscopic property dependence on pore fluid chemistry must be accounted for in sediment studies involving subsurface flow and sediment stability analyses, as well as in engineered flow situations such as groundwater pollutant remediation, hydrocarbon migration, or other energy resource extraction applications. This study demonstrates how the liquid limit‐based electrical sensitivity index can be used to predict sediment compressibility changes due to pore fluid chemistry changes. Laboratory tests of electrical sensitivity, sedimentation, and compressibility illustrate mechanisms linking microscale and macroscale processes for selected pure, end‐member fines. A specific application considered here is methane extraction via depressurization of gas hydrate‐bearing sediment, which causes a dramatic pore water salinity drop concurrent with sediment being compressed by the imposed effective stress increase.

Journal of Geophysical Research↗
USGS2019

Variability in results from mineralogical and organic geochemical interlaboratory testing of U. S. Geological Survey shale reference materials

The expansion of unconventional petroleum resource exploration and production in the United States has led to an increase in source rock characterization efforts, particularly related to bulk organic and mineralogical properties. To support the analytical and research needs of industry and academia, as well as internal work, the U.S. Geological Survey (USGS) has collected and prepared shale geochemical reference materials (GRMs) from several major shale petroleum systems in the U.S. The sources of these materials are the Late Cretaceous Boquillas (lower Eagle Ford-equivalent) Formation (roadcut near Del Rio, TX), Late Cretaceous Mancos Shale (outcrop near Delta, CO), Devonian–Mississippian Woodford Shale (outcrop near Ardmore, OK), Late Cretaceous Niobrara Formation (quarry near Lyons, CO), Middle Devonian Marcellus Shale (creek bed in LeRoy, NY), and Eocene Mahogany zone oil shale of the Green River Formation (oil shale mine near Rifle, CO). Of particular interest in the development of these GRMs has been the examination of variability between laboratories and specific methods or instruments in commonly made measurements, including major- and trace-element concentrations, X-ray diffraction (XRD) mineralogy, total organic carbon (TOC) content, and programmed pyrolysis (PP) parameters. For the component concentrations and parameters we measured, the techniques and instrument types included: (1) elemental analysis by X-ray fluorescence, inductively coupled plasma mass spectrometry, and instrumental neutron activation analysis; (2) XRD mineralogy with various preparatory methods (spray drying or micronizing with or without internal standard); (3) TOC by combustion with infrared detection after carbonate removal or the PP approach; (4) PP by Rock-Eval 2 or more recently developed instruments (Rock-Eval 6, Source Rock Analyzer or SRA, and Hydrocarbon Analyzer With Kinetics or HAWK). Overall, the results showed that the selected shales cover a wide range of source rock organic and mineralogical properties. Major- and trace-element chemistry results showed low heterogeneity consistent with other USGS GRMs. Comparison of TOC results showed coefficients of variation (COV) of around 5% and the most consistent organic geochemical results between different laboratories and methods. Arguably the most relevant PP measurement, S2 or kerogen hydrocarbon-generating potential (mg-HC/g-rock), showed a somewhat wider range of variability than TOC (COV ~10%), but was consistent between the three modern instruments and the industry-standard Rock-Eval 2. Major phase mineralogy (mineral concentrations ≥10 wt. %, organic-free basis) were comparable between laboratories, but variability in minor phase identification and quantification was observed. Utilization of these shale GRMs as quality control samples and testing materials is expected to help support analytical and experimental efforts in the continued development of unconventional petroleum resources.

Colorado, Texas, Oklahoma↗
USGS2007

Selected field parameters from streams and preliminary analytical data from water and macroinvertebrate samples, Central Colorado Assessment Project, task, 2004 and 2005

The U.S. Geological Survey (USGS) Central Colorado Assessment Project (CCAP) began in October 2003 and is planned to last through September 2008. One major goal of this project is to compare the relationships between surface-water chemistry and aquatic fauna in mined and unmined areas. To accomplish this goal, we are conducting a State-scale reconnaissance sampling program, in which we are collecting water and macroinvertebrate samples. Selected results from the first two years of project analyses are reported here. We plan to develop statistical models and use geographic information system (GIS) technology to quantify the relationships between ecological indicators of metal contamination in Rocky Mountain streams and water quality, landscape and land-use characteristics (for example, mine density, geology, geomorphology, vegetation, topography). Our research will test the hypothesis that physicochemical variables and ecological responses to metal concentrations in stream water in Rocky Mountain streams are ultimately determined largely by historical land uses.

Colorado↗
USGS2002

Direct conversion of terpenylalkanolamines to ethylidyne N -nitroso compounds

A series of mono- and diterpenylalkanolamines bearing isopropylidene functionality on the terpene group was reacted with sodium nitrite in aqueous acetic acid to yield ethylidyne N -nitroso analogues. The key feature of this direct conversion involved initial N-nitrosation followed by apparent elimination of a "CH 4 " unit (not necessarily methane) from the isopropylidene double bond. The product distribution data for ethylidyne nitrosamines derived from tertiary terpenyl alkanolamines reflect the conformational outcome of the nitrosative dealkylation process. For β , γ -unsaturated allylic diterpenylethanolamines, electronic effects appeared to be important for controlling the product distribution of ethylidyne nitrosamines in light of the highly selective α -cleavage observed in the nitrosation reactions.

Journal of Organic Chemistry↗
USGS2020

Geochemical characterization of groundwater evolution south of Grand Canyon, Arizona (USA)

Better characterization of the geochemical evolution of groundwater south of Grand Canyon, Arizona (USA), is needed to understand natural conditions and assess potential effects from breccia-pipe uranium mining in the region. Geochemical signatures of groundwater at 28 sampling locations were evaluated; baseline concentrations for select trace elements (As, B, Ba, Cr, Li, Mo, Rb, Se, Sr, Th, Tl, U, V) were established, and anomalous chemistry characteristics were identified. Concentrations at some groundwater sites exceeded the USEPA drinking water standard for As of 10 μg/L (Red Canyon, Miners, JT, Havasu, and Warm Springs) and U of 30 μg/L (Salt Creek Spring). Four springs from the study area (Blue, Havasu, Fern, and Warm Springs) had unique chemistry, which may indicate a deep flow path or potential contribution of fluids from lower in the crust. Other springs in the study area were distinguished by major anion water type: sulfate, bicarbonate, and a mixture of the two. Water type distinctions were somewhat spatially segregated, with sulfate type present on the western side of the study area, bicarbonate type on the eastern side, and a mixture of the two interspersed between the endmember sites. Sulfate-type water from this study area had low strontium isotopic ratio (87Sr/86Sr) values. The location of spring discharge within single drainages of the Grand Canyon may influence chemistry, as groundwater discharging from bedrock was altered after flowing through alluvial material. Geochemical analysis of groundwater in Grand Canyon indicates the importance of continued monitoring and better understanding of short-term chemical fluctuations.

Arizona↗