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At least 91 records · Page 5Linked to original sources
USGS2024

Spatio-temporal ecological models via physics-informed neural networks for studying chronic wasting disease

To mitigate the negative effects of emerging wildlife diseases in biodiversity and public health it is critical to accurately forecast pathogen dissemination while incorporating relevant spatio-temporal covariates. Forecasting spatio-temporal processes can often be improved by incorporating scientific knowledge about the dynamics of the process using physical models. Ecological diffusion equations are often used to model epidemiological processes of wildlife diseases where environmental factors play a role in disease spread. Physics-informed neural networks (PINN) are deep learning algorithms that constrain neural network predictions based on physical laws and therefore are powerful forecasting models useful even in cases of limited and imperfect training data. In this paper, we develop a novel ecological modeling tool using PINNs, which fits a feedforward neural network and simultaneously performs parameter identification in a partial differential equation (PDE) with varying coefficients. We demonstrate the applicability of our model by comparing it with the commonly used Bayesian stochastic partial differential equation method and traditional machine learning approaches, showing that our proposed model exhibits superior prediction and forecasting performance when modeling chronic wasting disease in deer in Wisconsin. Furthermore, our model provides the opportunity to obtain scientific insights into spatiotemporal covariates affecting spread and growth of diseases. This work contributes to future machine learning and statistical methodology development by studying spatio-temporal processes enhanced by prior physical knowledge.

Spatial Statistics↗
USGS2012

Biotic, water-quality, and hydrologic metrics calculated for the analysis of temporal trends in National Water Quality Assessment Program Data in the Western United States

The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program was established by Congress in 1991 to collect long-term, nationally consistent information on the quality of the Nation's streams and groundwater. The NAWQA Program utilizes interdisciplinary and dynamic studies that link the chemical and physical conditions of streams (such as flow and habitat) with ecosystem health and the biologic condition of algae, aquatic invertebrates, and fish communities. This report presents metrics derived from NAWQA data and the U.S. Geological Survey streamgaging network for sampling sites in the Western United States, as well as associated chemical, habitat, and streamflow properties. The metrics characterize the conditions of algae, aquatic invertebrates, and fish. In addition, we have compiled climate records and basin characteristics related to the NAWQA sampling sites. The calculated metrics and compiled data can be used to analyze ecohydrologic trends over time.

Open-File Report↗
USGS2019

Physicochemical controls on zones of higher coral stress where Black Band Disease occurs at Mākua Reef, Kauaʻi, Hawaiʻi

Pervasive and sustained coral diseases contribute to the systemic degradation of reef ecosystems, however, to date an understanding of the physicochemical controls on a coral disease event is still largely lacking. Water circulation and residence times and submarine groundwater discharge all determine the degree to which reef organisms are exposed to the variable chemistry of overlying waters; understanding these physical controls is thus necessary to interpret spatial patterns in coral health. The recent discovery of coral Black Band Disease at Mākua Reef on Kauaʻi, Hawaiʻi prompted an investigation into the physicochemical drivers and geomorphic controls of reef water circulation, and the temporally variable nutrient fluxes derived from submarine groundwater discharge. Results reveal localized stagnant water parcels at Mākua Reef where groundwater-derived high nutrient loading and low salinities act in concert as stressors to coralline health – and where Black Band Disease was uniquely identified. The observed high nutrient levels during low tide conditions are likely associated with nearby upstream cesspools and drain fields. Information obtained using such a multidisciplinary approach has direct value for successful management of coastal aquifers and the health and sustainability of adjacent nearshore coral reef ecosystems.

Hawaii↗
USGS2003

Applying indicators of hydrologic alteration to Texas streams: overview of methods with examples from the Trinity River basin

Streamflow is a component of aquatic ecosystem health, and long-term alteration of streamflow characteristics can produce large changes in aquatic ecosystem structure and function. The physical, chemical, and biological properties of aquatic ecosystems are all affected by the magnitude and frequency of streamflow. For example, the physical structure (hydrogeomorphology) of aquatic habitats is a property of the interaction between streamflow magnitude and frequency and the physical landscape (Leopold and others, 1992). Chemical processes are affected by changes in water residence time, which is a function of streamflow. Similarly, the structure and function of biological communities associated with stream ecosystems depend in large part on the hydrologic regime (Poff and Ward, 1989, 1990; Sparks, 1992). Within-year variation in streamflow is essential to the survival, growth, and reproduction of aquatic species. Altering streamflow magnitude and frequency and within-year variability has the potential to modify critical aspects of the physical habitat (Bain and others, 1988). Documenting the degree to which streamflow has been modified by the cumulative effects of water development is critical to assessing aquatic ecosystem health. The U.S. Geological Survey (USGS), in cooperation with the Texas Commission on Environmental Quality, conducted a study of the application of the Indicators of Hydrologic Alteration (IHA) methods developed by Richter and others (1996, 1997) to identify streams at risk for biological impairment from the loss of streamflow-dependent habitat. This report provides a brief overview of selected IHA methods for assessing hydrologic alteration; presents examples that illustrate the application of the methods using streamflow data from a subset of USGS stations in the Trinity River Basin, Texas, analyzed in the study; and addresses applicability of the methods statewide.

Texas↗
USGS2005

Risk analysis for biological hazards: What we need to know about invasive species

Risk analysis for biological invasions is similar to other types of natural and human hazards. For example, risk analysis for chemical spills requires the evaluation of basic information on where a spill occurs; exposure level and toxicity of the chemical agent; knowledge of the physical processes involved in its rate and direction of spread; and potential impacts to the environment, economy, and human health relative to containment costs. Unlike typical chemical spills, biological invasions can have long lag times from introduction and establishment to successful invasion, they reproduce, and they can spread rapidly by physical and biological processes. We use a risk analysis framework to suggest a general strategy for risk analysis for invasive species and invaded habitats. It requires: (1) problem formation (scoping the problem, defining assessment endpoints); (2) analysis (information on species traits, matching species traits to suitable habitats, estimating exposure, surveys of current distribution and abundance); (3) risk characterization (understanding of data completeness, estimates of the “potential” distribution and abundance; estimates of the potential rate of spread; and probable risks, impacts, and costs); and (4) risk management (containment potential, costs, and opportunity costs; legal mandates and social considerations and information science and technology needs).

Risk Analysis↗
USGS2010

Climate change and wildlife health: direct and indirect effects

Climate change will have significant effects on the health of wildlife, domestic animals, and humans, according to scientists. The Intergovernmental Panel on Climate Change projects that unprecedented rates of climate change will result in increasing average global temperatures; rising sea levels; changing global precipitation patterns, including increasing amounts and variability; and increasing midcontinental summer drought (Intergovernmental Panel on Climate Change, 2007). Increasing temperatures, combined with changes in rainfall and humidity, may have significant impacts on wildlife, domestic animal, and human health and diseases. When combined with expanding human populations, these changes could increase demand on limited water resources, lead to more habitat destruction, and provide yet more opportunities for infectious diseases to cross from one species to another. Awareness has been growing in recent years about zoonotic diseases— that is, diseases that are transmissible between animals and humans, such as Lyme disease and West Nile virus. The rise of such diseases results from closer relationships among wildlife, domestic animals, and people, allowing more contact with diseased animals, organisms that carry and transmit a disease from one animal to another (vectors), and people. Disease vectors include insects, such as mosquitoes, and arachnids, such as ticks. Thus, it is impossible to separate the effects of global warming on wildlife from its effects on the health of domestic animals or people. Climate change, habitat destruction and urbanization, the introduction of exotic and invasive species, and pollution—all affect ecosystem and human health. Climate change can also be viewed within the context of other physical and climate cycles, such as the El Niño Southern Oscillation (El Niño), the North Atlantic Oscillation, and cycles in solar radiation that have profound effects on the Earth’s climate. The effects of climate change on wildlife disease are summarized in several areas of scientific study discussed briefly below: geographic range and distribution of wildlife diseases, plant and animal phenology (Walther and others, 2002), and patterns of wildlife disease, community and ecosystem composition, and habitat degradation.

Fact Sheet↗
USGS2001

Burrowing mayflies ( Hexagenia ) as indicators of ecosystem health

Three State of the Lakes Ecosystem Conferences have been held since 1996 to encourage the development of Great Lakes indicators of ecosystem health for use in reporting on progress in restoring and maintaining the chemical, physical and biological integrity of the Great Lakes ecosystem. Here we report on the development of an indicator based on burrowing mayflies , Hexagenia (Ephemeroptera: Ephemeridae), using production and biomass as the indicator metrics. Burrowing mayflies were selected because they (1) were historically abundant in unpolluted, soft-bottomed mesotrophic habitats throughout the Great Lakes, (2) are intolerant of and were extirpated by pollution in most of those habitats during the 1940s to1950s, (3) have shown the ability to recover in one of those habitats following pollution abatement, (4) are ecologically important as bioturbators of lakebed sediments and as trophic integrators that link detrital energy resources directly to fishes that feed preferentially on them, and (5) have highly visible mating flights, which carry the message directly to an informed public that the source water body is healthy. In addition, their annual production can be estimated from their mean annual biomass by the sizefrequency method. Productivity and biomass can also could be estimated with a 'cohort-direct' method, using the biomass of mature nymphs collected in May or early June from the cohort that is about to emerge as subimagos in late June or early July. Although both the size-frequency and cohort-direct methods provide reliable estimates of productivity and biomass, the latter method greatly reduces sample collection and processing effort and thus makes it feasible to use Hexagenia as an indicator of ecosystem health in surveys requiring the collection of large numbers of samples.

Aquatic Ecosystem Health & Management↗
USGS2004

The effects of urbanization on the biological, physical, and chemical characteristics of coastal New England streams

During August 2000, responses of biological communities (invertebrates, fish, and algae), physical habitat, and water chemistry to urban intensity were compared among 30 streams within 80 miles of Boston, Massachusetts. Sites chosen for sampling represented a gradient of the intensity of urban development (urban intensity) among drainage basins that had minimal natural variability. In this study, spatial differences were used as surrogates for temporal changes to represent the effects of urbanization over time. The degree of urban intensity for each drainage basin was characterized with a standardized urban index (0-100, lowest to highest) derived from land cover, infrastructure, and socioeconomic variables. Multivariate and multimetric analyses were used to compare urban index values with biological, physical, and chemical data to determine how the data indicated responses to urbanization. Multivariate ordinations were derived for the invertebrate-, fish-, and algae-community data by use of correspondence analysis, and ordinations were derived for the chemical and physical data by use of principal-component analysis. Site scores from each of the ordinations were plotted in relation to the urban index to test for a response. In all cases, the primary axis scores showed the strongest response to the urban index, indicating that urbanization was a primary factor affecting the data ordination. For the multimetric analyses, each of the biological data sets was used to calculate a series of community metrics. For the sets of chemical and physical data, the individual variables and various combinations of individual variables were used as measured and derived metrics, respectively. Metrics that were generally most responsive to the urban index for each data set included: EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa for invertebrates; cyprinid taxa for fish; diatom taxa for algae; bicarbonate, conductivity, and nitrogen for chemistry; and water depth and temperature for physical habitat. The slopes of the responses generally were higher between the urban index values of 0 to 35, indicating that the greatest change in aquatic health may occur between low and moderate levels of urban intensity. Additionally, many of the responses showed that at urban index values greater than 35, there was a threshold effect where the response variable no longer changed with respect to urban intensity. Recognizing and understanding this type of response is important in management and monitoring programs that rely on decisive interpretations of variable responses. Any biological, physical, or chemical variable that is used to characterize stream health over a gradient of disturbance would not be a reliable indicator when a level of disturbance is reached where the variable does not respond in a predictable manner.

Maine, Massachusetts, New Hampshire↗
USGS1985

Wildlife health implications of sewage disposal in wetlands

Wildlife health concerns associated with disposal of sewage effluent in wetlands are of three primary types: (1) introduction of pathogens, (2) introduction of pollutants that adversely impact on host body defense mechanisms, and (3) changes in the physical and chemical properties of wetlands that favor the development and maintenance of disease problems. Unlike the situation with human health concerns, introduction of pathogens is not the major concern regarding wildlife health. Instead, the focus of attention needs to be directed at environmental changes likely to take place as a result of effluent discharges into different types of wetlands. Unless these changes are adequately addressed from a disease perspective, marshes utilized for sewage disposal could become disease incubators and wildlife death traps. This result would be unfortunate because the backlash would likely negate the potentially beneficial aspects of the use of sewage wastewater for the creation of new wetlands and have a severe impact on progress being made towards evaluation of the compatibility of wildlife and sewage effluents.

Book chapter↗
USGS2014

The environmental and medical geochemistry of potentially hazardous materials produced by disasters

Many natural or human-caused disasters release potentially hazardous materials (HM) that may pose threats to the environment and health of exposed humans, wildlife, and livestock. This chapter summarizes the environmentally and toxicologically significant physical, mineralogical, and geochemical characteristics of materials produced by a wide variety of recent disasters, such as volcanic eruptions, hurricanes and extreme storms, spills of mining/mineral-processing wastes or coal extraction by-products, and the 2001 attacks on and collapse of the World Trade Center towers. In describing these characteristics, this chapter also illustrates the important roles that geochemists and other earth scientists can play in environmental disaster response and preparedness. In addition to characterizing in detail the physical, chemical, and microbial makeup of HM generated by the disasters, these roles also include (1) identifying and discriminating potential multiple sources of the materials; (2) monitoring, mapping, and modeling dispersal and evolution of the materials in the environment; (3) understanding how the materials are modified by environmental processes; (4) identifying key characteristics and processes that influence the materials' toxicity to exposed humans and ecosystems; (5) estimating shifts away from predisaster environmental baseline conditions; and (6) using geochemical insights learned from past disasters to help estimate, prepare for, and increase societal resilience to the environmental and related health impacts of future disasters.

Book chapter↗
USGS2023

Ecology and ecosystem impacts of submerged and floating aquatic vegetation in the Sacramento-San Joaquin Delta

Substantial increases in non-native aquatic vegetation have occurred in the upper San Francisco Estuary over the last 2 decades, largely from the explosive growth of a few submerged and floating aquatic plant species. Some of these species act as ecosystem engineers by creating conditions that favor their further growth and expansion as well as by modifying habitat for other organisms. Over the last decade, numerous studies have investigated patterns of expansion and turn-over of aquatic vegetation species; effects of vegetation on ecosystem health, water quality, and habitat; and effects of particular species or communities on physical processes such as carbon and sediment dynamics. Taking a synthetic approach to evaluate what has been learned over the last few years has shed light on just how significant aquatic plant species and communities are to ecosystems in the Sacramento-San Joaquin Delta. Aquatic vegetation affects every aspect of the physical and biotic environment, acting as ecosystem engineers on the landscape. Furthermore, their effects are constantly changing across space and time, leaving many unanswered questions about the full effects of aquatic vegetation on Delta ecosystems and what future effects may result, as species shift in distribution and new species are introduced. Remaining knowledge gaps underlie our understanding of aquatic macrophyte effects on Delta ecosystems, including their roles and relationships with respect to nutrients and nutrient cycling, evapotranspiration and water budgets, carbon and sediment, and emerging effects on fish species and their habitats. This paper explores our current understanding of submerged and floating aquatic vegetation (SAV and FAV) ecology with respect to major aquatic plant communities, observed patterns of change, interactions between aquatic vegetation and the physical environment, and how these factors affect ecosystem services and disservices within the upper San Francisco Estuary.

California↗
USGS2025

Learning complex spatial dynamics of wildlife diseases with machine learning-guided partial differential equations

Emerging wildlife pathogens often display geographic variability due to landscape heterogeneity. Modeling approaches capable of learning complex, non-linear spatial dynamics of diseases are needed to rigorously assess and mitigate the effects of pathogens on wildlife health and biodiversity. We propose a novel machine learning (ML)-guided approach that leverages prior physical knowledge of ecological systems, using partial differential equations. We present our approach, taking advantage of the universal function approximation property of neural networks for flexible representation of the underlying dynamics of the geographic spread and growth of wildlife diseases. We demonstrate the benefits of our approach by comparing its forecasting power with commonly used methods and highlighting the obtained insights on disease dynamics. Additionally, we show the theoretical guarantees for the approximation error of our model. We illustrate the implementation of our ML-guided approach using data from white-nose syndrome (WNS) outbreaks in bat populations across the US. WNS is an infectious fungal disease responsible for significant declines in bat populations. Our results on WNS are useful for disease surveillance and bat conservation efforts. Our methods can be broadly used to assess the effects of environmental and anthropogenic drivers impacting wildlife health and biodiversity.

Environmental Data Science↗
USGS2012

Linking physical monitoring to coho and Chinook salmon populations in the Redwood Creek Watershed, California—Summary of May 3–4, 2012 Workshop

On Thursday, May 3, 2012, a science workshop was held at the Redwood National and State Parks (RNSP) office in Arcata, California, with researchers and resource managers working in RNSP to share data and expert opinions concerning salmon populations and habitat in the Redwood Creek watershed. The focus of the workshop was to discuss how best to synthesize physical and biological data related to the freshwater and estuarine phases of salmon life cycles in order to increase the understanding of constraints on salmon populations. The workshop was hosted by the U.S. Geological Survey (USGS) Status and Trends (S&T) Program National Park Monitoring Project ( http://www.fort.usgs.gov/brdscience/ParkMonitoring.htm ), which supports USGS research on priority topics (themes) identified by the National Park Service (NPS) Inventory and Monitoring Program (I&M) and S&T. The NPS has organized more than 270 parks with significant natural resources into 32 Inventory and Monitoring (I&M) Networks ( http://science.nature.nps.gov/im/networks.cfm ) that share funding and core professional staff to monitor the status and long-term trends of selected natural resources ( http://science.nature.nps.gov/im/monitor ). All 32 networks have completed vital signs monitoring plans (available at http://science.nature.nps.gov/im/monitor/MonitoringPlans.cfm ), containing background information on the important resources of each park, conceptual models behind the selection of vital signs for monitoring the condition of natural resources, and the selection of high priority vital signs for monitoring. Vital signs are particular physical, chemical, and biological elements and processes of park ecosystems that represent the overall health or condition of the park, known or hypothesized effects of stressors, or elements that have important human values (Fancy and others, 2009). Beginning in 2009, the I&M program funded projects to analyze and synthesize the biotic and abiotic data generated by vital signs monitoring and previous in-park natural resource monitoring and inventories to provide useful information, models, and tools to park managers for addressing resource management issues. The workshop described in this report is an element of the project funded by USGS NPS-I&M program to conduct a synthesis of salmon-related datasets in the Klamath (KLMN) and San Francisco Bay Area (SFAN) networks of national parks. The synthesis focused on four park units: Redwood National Park (KLMN), Point Reyes National Seashore, Muir Woods National Monument, and Golden Gate National Recreation Area (SFAN).

California↗
USGS2012

Quality of streams in Johnson County, Kansas, 2002--10

Stream quality in Johnson County, northeastern Kansas, was assessed on the basis of land use, hydrology, stream-water and streambed-sediment chemistry, riparian and in-stream habitat, and periphyton and macroinvertebrate community data collected from 22 sites during 2002 through 2010. Stream conditions at the end of the study period are evaluated and compared to previous years, stream biological communities and physical and chemical conditions are characterized, streams are described relative to Kansas Department of Health and Environment impairment categories and water-quality standards, and environmental factors that most strongly correlate with biological stream quality are evaluated. The information is useful for improving water-quality management programs, documenting changing conditions with time, and evaluating compliance with water-quality standards, total maximum daily loads (TMDLs), National Pollutant Discharge Elimination System (NPDES) permit conditions, and other established guidelines and goals. Constituent concentrations in water during base flow varied across the study area and 2010 conditions were not markedly different from those measured in 2003, 2004, and 2007. Generally the highest specific conductance and concentrations of dissolved solids and major ions in water occurred at urban sites except the upstream Cedar Creek site, which is rural and has a large area of commercial and industrial land less than 1 mile upstream on both sides of the creek. The highest base-flow nutrient concentrations in water occurred downstream from wastewater treatment facilities. Water chemistry data represent base-flow conditions only, and do not show the variability in concentrations that occurs during stormwater runoff. Constituent concentrations in streambed sediment also varied across the study area and some notable changes occurred from previously collected data. High organic carbon and nutrient concentrations at the rural Big Bull Creek site in 2003 decreased to at least one-fourth of those concentrations in 2007 and 2010 likely because of the reduction in upstream wastewater discharge contributions. The highest concentrations of trace metals in 2010 occurred at urban sites on Mill and Indian Creeks. Zinc was the only metal to exceed the probable effects concentration in 2010, which occurred at a site on Indian Creek. In 2007, chromium and nickel at the upstream urban Cedar Creek site exceeded the probable effects concentrations, and in 2003, no metals exceeded the probable effects concentrations. Of 72 organic compounds analyzed in streambed sediment, 26 were detected including pesticides, polycyclic aromatic hydrocarbons (PAHs), fuel products, fragrances, preservatives, plasticizers, manufacturing byproducts, flame retardants, and disinfectants. All 6 PAH compounds analyzed were detected, and the probable effects concentrations for 4 of the 6 PAH compounds analyzed were exceeded in 2010. Only five pesticide compounds were detected in streambed sediment, including carbazole and four pyrethroid compounds. Chronic toxicity guidelines for pyrethroid compounds were exceeded at five sites. Biological conditions reflected a gradient in urban land use, with the less disturbed streams located in rural areas of Johnson County. About 19 percent of sites in 2010 (four sites) were fully supporting of aquatic life on the basis of the four metrics used by Kansas Department of Health and Environment to categorize sites. This is a notable difference compared to previous years when no sites (in 2003 and 2004) or just one site (in 2007) was fully supporting of aquatic life. Multimetric macroinvertebrate scores improved at the Big Bull Creek site where wastewater discharges were reduced in 2007. Environmental variables that consistently were highly negatively correlated with biological conditions were percent impervious surface and percent urban land use. In addition, density of stormwater outfall points adjacent to streams was significantly negatively correlated with biological conditions. Specific conductance of water and sum of PAH concentrations in streambed sediment also were significantly negatively correlated with biological conditions. Total nitrogen in water and total phosphorus in streambed sediment were correlated with most of the invertebrate variables, which is a notable difference from previous analyses using smaller datasets, in which nutrient relations were weak or not detected. The most important habitat variables were sinuosity, length and continuity of natural buffers, riffle substrate embeddedness, and substrate cover diversity, each of which was correlated with all invertebrate metrics including a 10-metric combined score. Correlation analysis indicated that if riparian and in-stream habitat conditions improve then so might invertebrate communities and stream biological quality. Sixty-two percent of the variance in macroinvertebrate community metrics was explained by the single environmental factor, percent impervious surface. Invertebrate responses to urbanization in Johnson County indicated linearity rather than identifiable thresholds. Multiple linear regression models developed for each of the four macroinvertebrate metrics used to determine aquatic-life-support status indicated that percent impervious surface, as a measure of urban land use, explained 34 to 67 percent of the variability in biological communities. Results indicate that although multiple factors are correlated with stream quality degradation, general urbanization, as indicated by impervious surface area or urban land use, consistently is determined to be the fundamental factor causing change in stream quality. Effects of urbanization on Johnson County streams are similar to effects described in national studies that assess effects of urbanization on stream health. Individually important environmental factors such as specific conductance of water, PAHs in streambed sediment, and stream buffer conditions, are affected by urbanization and, collectively, all contribute to stream impairments. Policies and management practices that may be most important in protecting the health of streams in Johnson County are those minimizing the effects of impervious surface, protecting stream corridors, and decreasing the loads of sediment, nutrients, and toxic chemicals that directly enter streams through stormwater runoff and discharges.

Kansas↗
USGS1994

Physical, chemical, and biological data for detailed study of irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, 1991-92

Because of concerns about potential effects of irrigation drainage on fish and wildlife resources and on human health, the U.S. Department of the Interior initiated a program in 1985 to assess water-quality problems associated with Federal irrigation projects in the Western United States. Physical, chemical, and biological data were collected for a detailed study of irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, during 1991-92. This report lists onsite measurements and concen- trations of major constituents, trace elements, and stable isotopes for surface-water- and ground-water-sampling sites. Insecticide data collected in the Grand Valley are presented. Ranges of specific-conductance measurements and dissolved- oxygen concentrations for selected wells and a daily record of water-level altitude and specific conduc- tance for a well in the Grand Valley are presented. The report presents historical water-level and dissolved-solids data for two wells in the Grand Valley. Concentrations of trace elements, major constituents, total carbon, and organic carbon in bottom-sediment, bedrock, and in aquifer-sediment samples and semiquantitative data on clay and bulk mineralogy of samples of the Mancos Shale are presented. The report contains selenium-speciation data for selected water and bottom-sediment samples and selected aquifer-test results. Biological samples collected in the Uncompahgre Project area and in the Grand Valley included aquatic plants, aquatic invertebrates, fish, birds, and bird eggs. The report lists concentrations of trace elements in biological samples collected in 1991-92. A limited number of biological samples were analyzed for pesticides, PCB's, and polycyclic aromatic hydrocarbons.

Open-File Report↗
USGS2006

Performance assessments of nuclear waste repositories: A dialogue on their value and limitations

Performance Assessment (PA) is the use of mathematical models to simulate the long-term behavior of engineered and geologic barriers in a nuclear waste repository; methods of uncertainty analysis are used to assess effects of parametric and conceptual uncertainties associated with the model system upon the uncertainty in outcomes of the simulation. PA is required by the U.S. Environmental Protection Agency as part of its certification process for geologic repositories for nuclear waste. This paper is a dialogue to explore the value and limitations of PA. Two “skeptics” acknowledge the utility of PA in organizing the scientific investigations that are necessary for confident siting and licensing of a repository; however, they maintain that the PA process, at least as it is currently implemented, is an essentially unscientific process with shortcomings that may provide results of limited use in evaluating actual effects on public health and safety. Conceptual uncertainties in a PA analysis can be so great that results can be confidently applied only over short time ranges, the antithesis of the purpose behind long-term, geologic disposal. Two “proponents” of PA agree that performance assessment is unscientific, but only in the sense that PA is an engineering analysis that uses existing scientific knowledge to support public policy decisions, rather than an investigation intended to increase fundamental knowledge of nature; PA has different goals and constraints than a typical scientific study. The “proponents” describe an ideal, sixstep process for conducting generalized PA, here called probabilistic systems analysis (PSA); they note that virtually all scientific content of a PA is introduced during the model-building steps of a PSA, they contend that a PA based on simple but scientifically acceptable mathematical models can provide useful and objective input to regulatory decision makers. The value of the results of any PA must lie between these two views and will depend on the level of knowledge of the site, the degree to which models capture actual physical and chemical processes, the time over which extrapolations are made, and the proper evaluation of health risks attending implementation of the repository. The challenge is in evaluating whether the quality of the PA matches the needs of decision makers charged with protecting the health and safety of the public.

Risk Analysis↗
USGS2004

Science data in support of environmental health studies in the U.S.-Mexico border region

The border region of the United States and Mexico encompasses a vast and diverse array of physical settings and habitats that include wetlands, deserts, rangeland, mountains, and forests, which are unique in terms of the diversity of their water, mineral, and biological resources. The region is interconnected economically, politically, and socially owing to its binational heritage. In 1995, nearly 11 million people lived immediately adjacent to the border. By one account, that population could more than double by 2020. This rapid population growth and consequent economic development and land-use changes are pushing the limits of environmental sustainability and quality. Infrastructure development has lagged behind the rapid growth of the region, resulting in a shortage of water for municipal, agricultural, and industrial uses. These stressors threaten the quality of life in the region and raise concerns about the interdependence of environmental quality and human health. To allow for continued economic growth while protecting the area’s natural resources and fostering a high quality of life, the United States and Mexico need an improved understanding of the threats posed by these anthropogenic changes. Issues of particular concern include (1) contaminants in ground water, surface water, and biota from agricultural, municipal, and industrial activities; (2) airborne pollutants from fossil-fuel combustion and other activities; (3) contaminants from past and present mining activities and mineral deposits; and (4) pathogens, pharmaceuticals, hormones, and other contaminants released in treated and untreated human and animal wastewaters.

Fact Sheet↗
USGS2026

A novel drive-point multilevel system to investigate PFAS and other contaminants of global concern in the hyporheic zone of a wastewater effluent dominated stream

Contaminants found in treated wastewater discharged to streams, including pharmaceuticals and per- and polyfluoroalkyl substances (PFAS), are of global concern due to their deleterious effects on aquatic ecosystems and potential impacts to human health. Hyporheic zones have strong potential for contaminant attenuation. Assessing this potential requires collection of physical and biogeochemical data within the hyporheic zone. This study tested the applicability of a novel drive-point multilevel system (DP-MLS) for quantifying head profiles and characterizing contaminant concentrations in the hyporheic zone of a temperate region effluent dominated stream (EDS). DP-MLS, each with 4 ports, were installed in the stream bed at two sites, DS-1 and DS-2, 0.2 and 4.7 km downstream of the effluent outfall, respectively. Head profiles were measured and groundwater collected for analysis of pharmaceuticals and PFAS temporally over two years. The DP-MLS withstood rapid changes in stage, ice formation, and floating debris. Vertical hydraulic gradients (VHG) were generally upward but varied in magnitude indicating heterogeneity in hydraulic conductivity and variability in flow conditions. Upward VHG were also about 2X larger at DS-1 than at DS-2. Contaminant concentration profiles consistently showed penetration of pharmaceuticals and PFAS to 1 m below the bed at DS-2 while there was less penetration, lower groundwater concentrations, and more temporal variability in concentrations at DS-1. Integration of the physical and chemical data suggests weaker upwelling conditions at DS-2 are more easily reversed during periods of high stream stage, which could facilitate migration of wastewater contaminants into the bed. However, further studies incorporating other transport processes and reach scale dynamics are required to fully characterize these exchanges. Overall, this study demonstrates the efficacy of these novel DP-MLSs for characterization of the hyporheic zone and provides new insights into the occurrence, composition, and persistence of wastewater derived contaminants in the hyporheic zone of a well-studied EDS.

Iowa↗