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

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At least 901 records · Page 50Linked to original sources
USGS2023

Water, water everywhere, but every drop unique: Emerging challenges in the science to understand the role of contaminants in management of drinking water supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

GeoHealth↗
USGS2007

U.S. Geological Survey Mineral Resources Program - Science Supporting Mineral Resource Stewardship

The United States is the world's largest user of mineral resources. We use them to build our homes and cities, fertilize our food crops, and create wealth that allows us to buy goods and services. Individuals rarely use nonfuel mineral resources in their natural state - we buy light bulbs, not the silica, soda ash, lime, coal, salt, tungsten, copper, nickel, molybdenum, iron, manganese, aluminum, and zinc used to convert electricity into light. The USGS Mineral Resources Program (MRP) is the sole Federal source of scientific information and unbiased research on nonfuel mineral potential, production, and consumption, as well as on the environmental effects of minerals. The MRP also provides baseline geochemical, geophysical, and mineral-deposit data used to understand environmental issues related to extraction and use of mineral resources. Understanding how minerals, water, plants, and organisms interact contributes to our understanding of the environment, which is essential for maintaining human and ecosystem health. To support creation of economic and national security policies in a global context, MRP collects and analyzes data on essential mineral commodities from around the world.

Fact Sheet↗
USGS2001

Mechanisms of uranium interactions with hydroxyapatite: Implications for groundwater remediation

The speciation of U(VI) sorbed to synthetic hydroxyapatite was investigated using a combination of U L III -edge XAS, synchrotron XRD, batch uptake measurements, and SEM-EDS. The mechanisms of U(VI) removal by apatite were determined in order to evaluate the feasibility of apatite-based in-situ permeable reactive barriers (PRBs). In batch U(VI) uptake experiments with synthetic hydroxyapatite (HA), near complete removal of dissolved uranium (>99.5%) to <0.05 μM was observed over a range of total U(VI) concentrations up to equimolar of the total P in the suspension. XRD and XAS analyses of U(VI)-reacted HA at sorbed concentrations ≤4700 ppm U(VI) suggested that uranium(VI) phosphate, hydroxide, and carbonate solids were not present at these concentrations. Fits to EXAFS spectra indicate the presence of Ca neighbors at 3.81 Å. U-Ca separation, suggesting that U(VI) adsorbs to the HA surfaces as an inner-sphere complex. Uranium(VI) phosphate solid phases were not detected in HA with 4700 ppm sorbed U(VI) by backscatter SEM or EDS, in agreement with the surface complexation process. In contrast, U(VI) speciation in samples that exceeded 7000 ppm sorbed U(VI) included a crystalline uranium(VI) phosphate solid phase, identified as chernikovite by XRD. At these higher concentrations, a secondary, uranium(VI) phosphate solid was detected by SEM-EDS, consistent with chernikovite precipitation. Autunite formation occurred at total U:P molar ratios ≥0.2. Our findings provide a basis for evaluating U(VI) sorption mechanisms by commercially available natural apatites for use in development of PRBs for groundwater U(VI) remediation.

Environmental Science & Technology↗
USGS1988

Assessment of sea lamprey ( Petromyzon marinus ) predation by recovery of dead lake trout ( Salvelinus namaycush ) from Lake Ontario, 1982-85

During 1982-85, 89 dead lake trout ( Salvelinus namaycush ) were recovered with bottom trawls in U.S. waters of Lake Ontario: 28 incidentally during four annual fish-stock assessment surveys and 61 during fall surveys for dead fish. During the assessment surveys, no dead lake trout were recovered in April-June, one was recovered in August, and 27 were recovered in October or November, implying that most mortality from causes other than fishing occurred in the fall. The estimated numbers of dead lake trout between the 30- and 100-m depth contours in U.S. waters ranged from 16 000 (0.08 carcass/ha) in 1983 to 94 000 (0.46 carcass/ha) in 1982. Of 76 carcasses fresh enough to enable recognition of sea lamprey ( Petromyzon marinus ) wounds, 75 bore fresh wounds. Assuming that sea lamprey wounding rates on dead fish were the same as on live ones of the same length range (430-740 mm), the probability of 75 of the 76 dead lake trout bearing sea lamprey wounds was 3.5 x 10 -63 if death was independent of sea lamprey attack, thus strongly implicating sea lampreys as the primary cause of death of fish in the sample. The recovery of only one unwounded dead lake trout also suggested that natural mortality from causes other than sea lamprey attactks is negligible.

Lake Ontario↗
USGS1972

Hatchability tests with eggs from captive wood ducks

The effect of diet and artificial incubation on fertility and hatchability of wood duck (Aix sponsa) eggs and survival of young was measured. Hatchability of eggs from hens fed a diet containing 37 percent protein was increased significantly (P<0.05) over that of hens fed a diet containing 17 percent protein. Hatchability was also significantly (P<0.005) greater for eggs incubated 10 days under hens before being placed in an incubator than for eggs placed in an incubator for the entire period. Ducklings that hatched from naturally started incubation survived at a much higher rate (P<0.001). Egg fertility was not affected by the diets.

Poultry Science↗
USGS2014

Hydraulic modeling development and application in water resources engineering

The use of modeling has become widespread in water resources engineering and science to study rivers, lakes, estuaries, and coastal regions. For example, computer models are commonly used to forecast anthropogenic effects on the environment, and to help provide advanced mitigation measures against catastrophic events such as natural and dam-break floods. Linking hydraulic models to vegetation and habitat models has expanded their use in multidisciplinary applications to the riparian corridor. Implementation of these models in software packages on personal desktop computers has made them accessible to the general engineering community, and their use has been popularized by the need of minimal training due to intuitive graphical user interface front ends. Models are, however, complex and nontrivial, to the extent that even common terminology is sometimes ambiguous and often applied incorrectly. In fact, many efforts are currently under way in order to standardize terminology and offer guidelines for good practice, but none has yet reached unanimous acceptance. This chapter provides a view of the elements involved in modeling surface flows for the application in environmental water resources engineering. It presents the concepts and steps necessary for rational model development and use by starting with the exploration of the ideas involved in defining a model. Tangible form of those ideas is provided by the development of a mathematical and corresponding numerical hydraulic model, which is given with a substantial amount of detail. The issues of model deployment in a practical and productive work environment are also addressed. The chapter ends by presenting a few model applications highlighting the need for good quality control in model validation.

Book chapter↗
USGS1950

Geochemistry of ground water

The science of geochemistry is the study of the chemical composition of and actual or possible chemical changes in the crust of the earth. The subdivision of geochemistry concerned with ground water includes study of the nature and amounts of dissolved mineral matter in ground waters, the chemical and geologic changes that influence the kinds and amounts of substances carried in solution, and the chemical relationships between dissolved mineral matter in waters and minerals that make up the rocks in which the waters occur. As . thus defined, the field of geochemistry of ground water is very large. Although much work has been done in geochemistry in general, and in some phases of the geochemistry of ground water, the field remains to a large extent unexplored.

Economic Geology↗
USGS2010

The green alga, Cladophora, promotes Escherichia coli growth and contamination of recreational waters in Lake Michigan

A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. Th is study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations in water underlying mats were significantly greater than surrounding water (p < 0.001). Below mat E. coli increased as the stranded mats persisted at the beach swash zone. Water adjacent to Cladophora mats had lower E. coli concentrations, but surpassed EPA swimming criteria the majority of sampling days. A signifi cant positive association was found between E. coli concentrations attached to Cladophora and in underlying water (p < 0.001). The attached E. coli likely acted as a reservoir for populating water underlying the mat. Fecal bacterial pathogens, however, could not be detected by microbiological culture methods either attached to mat biomass or in underlying water. Removal of Cladophora mats from beach areas may improve aesthetic and microbial water quality at affected beaches. These associations and potential natural growth of E. coli in bathing waters call into question the efficacy of using E. coli as a recreational water quality indicator of fecal contaminations. Copyright ?? 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Journal of Environmental Quality↗
USGS2017

Reducing risk where tectonic plates collide

Most of the world’s earthquakes, tsunamis, landslides, and volcanic eruptions are caused by the continuous motions of the many tectonic plates that make up the Earth’s outer shell. The most powerful of these natural hazards occur in subduction zones, where two plates collide and one is thrust beneath another. The U.S. Geological Survey’s (USGS) “Reducing Risk Where Tectonic Plates Collide—A USGS Plan to Advance Subduction Zone Science” is a blueprint for building the crucial scientific foundation needed to inform the policies and practices that can make our Nation more resilient to subduction zone-related hazards.

Fact Sheet↗
USGS2016

Report from the workshop on climate downscaling and its application in high Hawaiian Islands, September 16–17, 2015

In the subtropical and tropical Pacific islands, changing climate is predicted to influence precipitation and freshwater availability, and thus is predicted to impact ecosystems goods and services available to ecosystems and human communities. The small size of high Hawaiian Islands, plus their complex microlandscapes, require downscaling of global climate models to provide future projections of greater skill and spatial resolution. Two different climate modeling approaches (physics-based dynamical downscaling and statistics-based downscaling) have produced dissimilar projections. Because of these disparities, natural resource managers and decision makers have low confidence in using the modeling results and are therefore are unwilling to include climate-related projections in their decisions. In September 2015, the Pacific Islands Climate Science Center (PICSC), the Pacific Islands Climate Change Cooperative (PICCC), and the Pacific Regional Integrated Sciences and Assessments (Pacific RISA) program convened a 2-day facilitated workshop in which the two modeling teams, plus key model users and resource managers, were brought together for a comparison of the two approaches, culminating with a discussion of how to provide predictions that are useable by resource managers. The proceedings, discussions, and outcomes of this Workshop are summarized in this Open-File Report.

Hawaii↗
USGS2008

Environmental chemical data for perishable sediments and soils collected in New Orleans, Louisiana, and along the Louisiana Delta following Hurricanes Katrina and Rita, 2005

In October 2005, nearly one month after Hurricanes Katrina and Rita, a team of scientists from the U.S. Geological Survey and the Missouri University of Science and Technology deployed to southern Louisiana to collect perishable environmental data resulting from the impacts of these storms. Perishable samples collected for this investigation are subject to destruction or ruin by removal, mixing, or natural decay; therefore, collection is time-critical following the depositional event. A total of 238 samples of sediment, soil, and vegetation were collected to characterize chemical quality. For this analysis, 157 of the 238 samples were used to characterize trace element, iron, total organic carbon, pesticide, and polychlorinated biphenyl concentrations of deposited sediment and associated shallow soils. In decreasing order, the largest variability in trace element concentration was detected for lead, vanadium, chromium, copper, arsenic, cadmium, and mercury. Lead was determined to be the trace element of most concern because of the large concentrations present in the samples ranging from 4.50 to 551 milligrams per kilogram (mg/kg). Sequential extraction analysis of lead indicate that 39.1 percent of the total lead concentration in post-hurricane sediment is associated with the iron-manganese oxide fraction. This fraction is considered extremely mobile under reducing environmental conditions, thereby making lead a potential health hazard. The presence of lead in post-hurricane sediments likely is from redistribution of pre-hurricane contaminated soils and sediments from Lake Pontchartrain and the flood control canals of New Orleans. Arsenic concentrations ranged from 0.84 to 49.1 mg/kg. Although Arsenic concentrations generally were small and consistent with other research results, all samples exceeded the U.S. Environmental Protection Agency’s Human Health Medium-Specific Screening Level of 0.39 mg/kg. Mercury concentrations ranged from 0.02 to 1.30 mg/kg. Comparing the mean mercury concentration present in post-hurricane samples with regional background data from the U.S. Geological Survey National Geochemical Dataset, indicates that mercury concentrations in post-hurricane sediment generally are larger. Sequential extraction analysis of 51 samples for arsenic indicate that 54.5 percent of the total arsenic concentration is contained in the extremely mobile iron-manganese oxide fraction. Pesticide and polychlorinated biphenyl Arochlor concentrations in post-hurricane samples were small. Prometon was the most frequently detected pesticide with concentrations ranging from 2.4 to 193 micrograms per kilogram (µg/kg). Methoxychlor was present in 22 samples with a concentration ranging from 3.5 to 3,510 µg/kg. Although methoxychlor had the largest detected pesticide concentration, it was well below the U.S. Environmental Protection Agency’s High-Priority Screening Level for residential soils. Arochlor congeners were not detected for any sample above the minimum detection level of 7.9 µg/kg.

Louisiana↗
USGS2000

Analytical group decision making in natural resources: Methodology and application

Group decision making is becoming increasingly important in natural resource management and associated scientific applications, because multiple values are treated coincidentally in time and space, multiple resource specialists are needed, and multiple stakeholders must be included in the decision process. Decades of social science research on decision making in groups have provided insights into the impediments to effective group processes and on techniques that can be applied in a group context. Nevertheless, little integration and few applications of these results have occurred in resource management decision processes, where formal groups are integral, either directly or indirectly. A group decision-making methodology is introduced as an effective approach for temporary, formal groups (e.g., workshops). It combines the following three components: (1) brainstorming to generate ideas; (2) the analytic hierarchy process to produce judgments, manage conflict, enable consensus, and plan for implementation; and (3) a discussion template (straw document). Resulting numerical assessments of alternative decision priorities can be analyzed statistically to indicate where group member agreement occurs and where priority values are significantly different. An application of this group process to fire research program development in a workshop setting indicates that the process helps focus group deliberations; mitigates groupthink, nondecision, and social loafing pitfalls; encourages individual interaction; identifies irrational judgments; and provides a large amount of useful quantitative information about group preferences. This approach can help facilitate scientific assessments and other decision-making processes in resource management.

Forest Science↗
USGS2016

Prospects and limitations of citizen science in invasive species management: A case study with Burmese pythons in Everglades National Park

Citizen-science programs have the potential to contribute to the management of invasive species, including Python molurus bivittatus (Burmese Python) in Florida. We characterized citizen-science–generated Burmese Python information from Everglades National Park (ENP) to explore how citizen science may be useful in this effort. As an initial step, we compiled and summarized records of Burmese Python observations and removals collected by both professional and citizen scientists in ENP during 2000–2014 and found many patterns of possible significance, including changes in annual observations and in demographic composition after a cold event. These patterns are difficult to confidently interpret because the records lack search-effort information, however, and differences among years may result from differences in search effort. We began collecting search-effort information in 2014 by leveraging an ongoing citizen-science program in ENP. Program participation was generally low, with most authorized participants in 2014 not searching for the snakes at all. We discuss the possible explanations for low participation, especially how the low likelihood of observing pythons weakens incentives to search. The monthly rate of Burmese Python observations for 2014 averaged ~1 observation for every 8 h of searching, but during several months, the rate was 1 python per >40 h of searching. These low observation-rates are a natural outcome of the snakes’ low detectability—few Burmese Pythons are likely to be observed even if many are present. The general inaccessibility of the southern Florida landscape also severely limits the effectiveness of using visual searches to find and remove pythons for the purposes of population control. Instead, and despite the difficulties in incentivizing voluntary participation, the value of citizen-science efforts in the management of the Burmese Python population is in collecting search-effort information.

Southeastern Naturalist↗
USGS2011

USGS St. Petersburg Coastal and Marine Science Center

Extreme storms, sea-level rise, and the health of marine communities are some of the major societal and environmental issues impacting our Nation's marine and coastal realm. The U.S. Geological Survey (USGS) in St. Petersburg, Fla., investigates processes related to these ecosystems and the societal implications of natural hazards and resource sustainability. As one of three centers nationwide conducting research within the USGS Coastal and Marine Geology Program, the center is integral towards developing an understanding of physical processes that will contribute to rational decisions regarding the use and stewardship of national coastal and marine environments.

Florida↗
USGS2015

Multiscale geophysical imaging of the critical zone

Details of Earth's shallow subsurface—a key component of the critical zone (CZ)—are largely obscured because making direct observations with sufficient density to capture natural characteristic spatial variability in physical properties is difficult. Yet this inaccessible region of the CZ is fundamental to processes that support ecosystems, society, and the environment. Geophysical methods provide a means for remotely examining CZ form and function over length scales that span centimeters to kilometers. Here we present a review highlighting the application of geophysical methods to CZ science research questions. In particular, we consider the application of geophysical methods to map the geometry of structural features such as regolith thickness, lithological boundaries, permafrost extent, snow thickness, or shallow root zones. Combined with knowledge of structure, we discuss how geophysical observations are used to understand CZ processes. Fluxes between snow, surface water, and groundwater affect weathering, groundwater resources, and chemical and nutrient exports to rivers. The exchange of gas between soil and the atmosphere have been studied using geophysical methods in wetland areas. Indirect geophysical methods are a natural and necessary complement to direct observations obtained by drilling or field mapping. Direct measurements should be used to calibrate geophysical estimates, which can then be used to extrapolate interpretations over larger areas or to monitor changing processes over time. Advances in geophysical instrumentation and computational approaches for integrating different types of data have great potential to fill gaps in our understanding of the shallow subsurface portion of the CZ and should be integrated where possible in future CZ research.

Reviews of Geophysics↗
USGS2017

Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography

Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new 10 Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, , underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ∼5000–6000 m a.s.l.; valleys at ∼2000–3000 m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (∼40–80 ka, ∼30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. Localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.

Earth and Planetary Science Letters↗