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At least 1,063 records · Page 59Linked to original sources
USGS2016

Inferring social structure and its drivers from refuge use in the desert tortoise, a relatively solitary species

For several species, refuges (such as burrows, dens, roosts, nests) are an essential resource for protection from predators and extreme environmental conditions. Refuges also serve as focal sites for social interactions, including mating, courtship, and aggression. Knowledge of refuge use patterns can therefore provide information about social structure, mating, and foraging success, as well as the robustness and health of wildlife populations, especially for species considered to be relatively solitary. In this study, we construct networks of burrow use to infer social associations in a threatened wildlife species typically considered solitary—the desert tortoise. We show that tortoise social networks are significantly different than null networks of random associations, and have moderate spatial constraints. We next use statistical models to identify major mechanisms behind individual-level variation in tortoise burrow use, popularity of burrows in desert tortoise habitat, and test for stressor-driven changes in refuge use patterns. We show that seasonal variation has a strong impact on tortoise burrow switching behavior. On the other hand, burrow age and topographical condition influence the number of tortoises visiting a burrow in desert tortoise habitat. Of three major population stressors affecting this species (translocation, drought, disease), translocation alters tortoise burrow switching behavior, with translocated animals visiting fewer unique burrows than residents. In a species that is not social, our study highlights the importance of leveraging refuge use behavior to study the presence of and mechanisms behind non-random social structure and individual-level variation. Our analysis of the impact of stressors on refuge-based social structure further emphasizes the potential of this method to detect environmental or anthropogenic disturbances.

Behavioral Ecology and Sociobiology↗
USGS2007

Mercury and methylmercury in water and bottom sediments of wetlands at Lostwood National Wildlife Refuge, North Dakota, 2003-04

Certain ecosystem types, particularly wetlands, have environmental characteristics that can make them particularly sensitive to mercury inputs and that can result in large mercury concentrations in fish or other aquatic biota. To provide information needed to make effective management decisions to decrease human and wildlife exposure to methylmercury in northern prairie pothole wetlands, the U.S. Geological Survey, in cooperation with the North Dakota Department of Health, conducted a study to assess mercury and methylmercury concentrations in wetlands at the Lostwood National Wildlife Refuge (the Refuge) in northwest North Dakota. In April 2003 and 2004, water and bottom-sediment samples were collected from 44 individual wetlands that were classified as one of four wetland types. Many factors that may affect methylmercury production were considered in the study. The prairie pothole wetlands at the Refuge had large ranges in major environmental characteristics. Hydrologic differences, most notably semiannual wetting and drying cycles, that are intrinsic to prairie pothole wetlands affected methylmercury concentrations. This likely resulted from the stimulation of anaerobic microbial activity following reflooding of soils, particularly soils containing substantial organic carbon. Among the four wetland types considered for this study, seasonal and semipermanent wetlands generally had the largest methylmercury concentrations. Regardless of wetland type, however, methylmercury concentrations at the Refuge are large in relation to reported concentrations for natural aquatic systems.

North Dakota↗
USGS1999

Exposure of great egret ( Ardea albus ) nestlings to mercury through diet in the Everglades ecosystem

We estimated exposure of great egret ( Ardea albus ) nestlings to mercury in food in the Florida Everglades, USA, by collecting regurgitated food samples during the 1993 to 1996 breeding seasons and during 1995 measured concentrations of mercury in individual prey items from those samples. Great egret nestlings had a diet composed predominantly of fish (>95% of biomass), though the species composition of fish in the diet fluctuated considerably among years. Great egrets concentrated on the larger fish available in the marsh, especially members of the Centrarchidae. The importance of all nonnative fish fluctuated from 0 to 32% of the diet by biomass and was dominated by pike killifish ( Belonesox belizanus ) and cichlids (Cichlidae). Total mercury concentrations in prey fish ranged from 0.04 to 1.40 mg/kg wet weight, and we found a significant relationship between mass of individual fish and mercury concentration. We estimated the concentration of total mercury in the diet as a whole by weighting the mercury concentration in a given fish species by the proportion of that species in the diet. We estimate that total mercury concentrations in the diets ranged among years from 0.37 to 0.47 mg/kg fish (4-year mean = 0.41 mg/kg). We estimated total mercury exposure in great egret nestlings by combining these mercury concentrations with measurements of food intake rate, as measured over the course of the nestling period in both lab and field situations. We estimate that, at the 0.41 mg/kg level, nestlings would ingest 4.32 mg total mercury during an 80-day nestling period. Captive feeding studies reported elsewhere suggest that this level of exposure in the wild could be associated with reduced fledging mass, increased lethargy, decreased appetite, and, possibly, poor health and juvenile survival.

Environmental Toxicology and Chemistry↗
USGS2015

Reconnaissance of contaminants in larval Pacific lamprey ( Entosphenus tridentatus ) tissues and habitats in the Columbia River Basin, Oregon and Washington, USA

Pacific lampreys ( Entosphenus tridentatus ) have resided in the Columbia River Basin for millennia and have great ecological and cultural importance. The role of habitat contamination in the recent decline of the species has rarely been studied and was the main objective of this effort. A wide range of contaminants (115 analytes) was measured in sediments and tissues at 27 sites across a large geographic area of diverse land use. This is the largest dataset of contaminants in habitats and tissues of Pacific lamprey in North America and the first study to compare contaminant bioburden during the larval life stage and the anadromous, adult portion of the life cycle. Bioaccumulation of pesticides, flame retardants, and mercury was observed at many sites. Based on available data, contaminants are accumulating in larval Pacific lamprey at levels that are likely detrimental to organism health and may be contributing to the decline of the species.

Oregon, Washington↗
USGS2025

Imidacloprid in United States rivers, 2013–2022: Persistent presence and emerging chronic hazard

Imidacloprid, a neonicotinoid insecticide, is used for agricultural and nonagricultural purposes and is toxic to nontarget organisms at low concentrations in aquatic ecosystems. A total of 12,547 water samples were collected from 2013 to 2022 from 77 rivers across the United States (U.S.) and were analyzed to evaluate detections and temporal trends in imidacloprid concentrations. Imidacloprid was detected in 44% of all samples, and the mean concentration, adjusted for nondetect samples, of 24.9 ng/L (median = 11.9 ng/L) was more than twice the chronic benchmark for freshwater invertebrates (10 ng/L). This potential hazard to aquatic life was persistent, with 44% of the sites having a median concentration exceeding the chronic benchmark. Half of the sites ( n = 38) had increasing trends, including large river sites along the Mississippi River. The mean increase was 10.6 ng/L over the past decade, while only six sites indicated decreasing trends. The estimated total loading of imidacloprid delivered to the Gulf of America from 2013 to 2022 was 129,489 kg (142.7 U.S. ton). The extensive presence of imidacloprid in U.S. waterways, the high percentage of sites with trends of increasing concentrations, and the prevalence of concentrations exceeding chronic benchmarks suggest widespread persistent risks to ecosystem health.

Environmental Science & Technology↗
USGS2002

Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: A national reconnaissance

To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during 1999 and 2000. The selection of sampling sites was biased toward streams susceptible to contamination (i.e. downstream of intense urbanization and livestock production). OWCs were prevalent during this study, being found in 80% of the streams sampled. The compounds detected represent a wide range of residential, industrial, and agricultural origins and uses with 82 of the 95 OWCs being found during this study. The most frequently detected compounds were coprostanol (fecal steroid), cholesterol (plant and animal steroid), N , N -diethyltoluamide (insect repellant), caffeine (stimulant), triclosan (antimicrobial disinfectant), tri(2-chloroethyl)phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite). Measured concentrations for this study were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria. Many compounds, however, do not have such guidelines established. The detection of multiple OWCs was common for this study, with a median of seven and as many as 38 OWCs being found in a given water sample. Little is known about the potential interactive effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of OWCs in the environment. In addition, results of this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.

Environmental Science & Technology↗
USGS2005

Using fish biomarkers to monitor improvements in environmental quality

The percentage of splenic tissue occupied by macrophage aggregates and hepatosomatic index (HSI) were evaluated in rock bass Ambloplites rupestris from Burlington Harbor, Vermont. In 1992, fish collected from the inner Burlington Harbor area had a significantly greater percentage of splenic tissue occupied by macrophage aggregates and greater HSI than did fish from reference sites. These biomarkers often are correlated with exposure to various contaminants (e.g., polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and some heavy metals, which were found in Burlington Harbor sediments during surveys in 1990 and 1991). Contaminants are believed to have entered Burlington Harbor through the city's main sewage treatment plant, which discharged effluent into the harbor for many years. In 1994, the city completed a significant upgrade of this treatment plant, which included an extension of the effluent pipe beyond the inner harbor area. In 1999, rock bass were again collected from Burlington Harbor as an index of whether there was any improvement in environmental quality. Our data showed a significantly lower percentage of splenic tissue occupied by macrophage aggregates and significantly lower HSI among nine age-4 rock bass in 1999 than among six age-4 rock bass in 1992. The significant changes in these biomarkers suggest decreased exposure to contaminants. Our study reinforces the value of macrophage aggregates and HSI as biomarkers of environmental contamination, and the correlation with remedial action shows their potential utility in documenting improvements in environmental conditions. ?? Copyright by the American Fisheries Society 2005.

Journal of Aquatic Animal Health↗
USGS2009

Sources and distribution of organic compounds using passive samplers in Lake Mead National Recreation Area, Nevada and Arizona, and their implications for potential effects on aquatic biota.

Th e delineation of lateral and vertical gradients of organic contaminants in lakes is hampered by low concentrations and nondetection of many organic compounds in water. Passive samplers (semipermeable membrane devices [SPMDs] and polar organic chemical integrative samplers [POCIS]) are well suited for assessing gradients because they can detect synthetic organic compounds (SOCs) at pg L-1 concentrations. Semi-permeable membrane devices and POCIS were deployed in Lake Mead, at two sites in Las Vegas Wash, at four sites across Lake Mead, and in the Colorado River downstream from Hoover Dam. Concentrations of hydrophobic SOCs were highest in Las Vegas Wash downstream from waste water and urban inputs and at 8 m depth in Las Vegas Bay (LVB) where Las Vegas Wash enters Lake Mead. Th e distribution of hydrophobic SOCs showed a lateral distribution across 10 km of Lake Mead from LVB to Boulder Basin. To assess possible vertical gradients of SOCs, SPMDs were deployed at 4-m intervals in 18 m of water in LVB. Fragrances and legacy SOCs were found at the greatest concentrations at the deepest depth. Th e vertical gradient of SOCs indicated that contaminants were generally confi ned to within 6 m of the lake bottom during the deployment interval. The high SOC concentrations, warmer water temperatures, and higher total dissolved solids concentrations at depth are indicative of a plume of Las Vegas Wash water moving along the lake bottom. Th e lateral and vertical distribution of SOCs is discussed in the context of other studies that have shown impaired health of fish exposed to SOCs.

Journal of Environmental Quality↗
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↗
USGS2010

Occurrence of Escherichia coli in the Cuyahoga River in the Cuyahoga Valley National Park, Ohio

There are several measures of the 'cleanliness' of a natural body of water, including concentrations of indicator bacteria, anthropogenic chemicals (chemicals derived from human activities), and nutrients, such as nitrogen and phosphorous. Escherichia coli (E. coli) is a bacterium that lives in the intestinal tract of warm-blooded animals, such as humans, deer, cows, and dogs. Most strains of E. coli are not harmful and are in fact beneficial to humans by aiding in the digestive process. A few strains, such as the O157 strain, produce toxins that can cause gastrointestinal illness, but occurrence of toxic strains in the environment is not common. E. coli is considered a good indicator bacterium because its occurrence in the environment indicates the presence of fecal contamination and therefore the possible presence of pathogenic organisms associated with feces. The U.S. Environmental Protection Agency (USEPA) recommends using measurements of E. coli to monitor freshwaters and set criteria for the concentration of bacteria that can be present in the water with minimal adverse human-health effects. Typically, a State's waters are assigned a recreational-use designation, such as bathing, primary-contact, or secondary contact waters, which is used to set the State's water-quality standards based on the USEPA criteria. The Cuyahoga River in the Cuyahoga Valley National Park is designated for primary-contact recreation; therefore, when concentrations of E. coli exceed 298 CFU/100mL, the river would be considered potentially unsafe for recreation.

Fact Sheet↗
USGS2019

Using UAS capabilities to help identify hummock-hollow formation and fragmentation in critical marsh habitat ( Spartina patens ) for mottled ducks in southeast Texas

For many years, marshes in the coastal areas from Texas to Louisiana have served as critical habitat for Anas fulvigula , the mottled duck. Mottled ducks are a priority species in the Texas/Louisiana Gulf Coast area and have been affected by critical habitat reduction. In recent years, mottled duck habitats have been threatened by natural and anthropogenic changes including urbanization, flooding, saltwater intrusion, and hydrologic alterations. These impacts are affecting the quality of habitat that is essential for the mottled duck nesting, feeding, and livelihood. Cumulative and synergistic effects of contamination and invasive species encroachment have also caused mottled duck habitat to be considered as some of the most critically endangered habitats in the United States. To help understand the environmental conditions that characterize the coastal landscape, U.S. Geological Survey researchers used an unmanned aerial system (UAS) to acquire high-resolution imagery to document current land and water spatial configuration and wetland health at McFaddin National Wildlife Refuge, Texas.

Texas↗
USGS2019

Pallid sturgeon basin-wide contaminants assessment

Pallid sturgeon (Scaphirhynchus albus), listed as endangered in 1990 under the federal Endangered Species Act (United States Fish and Wildlife Service (USFWS), 1990), have declined due to habitat loss, commercial fishing, and hybridization. Pollution in the Missouri and Mississippi Rivers has to-date only received minor attention as a factor in the on-going decline of wild pallid sturgeon populations (Jacobson et al. 2016a; Bergman 2008). Pallid sturgeon experts and contaminant specialists conceived of the Pallid Sturgeon Basin-Wide Contaminants Assessment (Assessment) to identify potentially harmful contaminants (contaminants of concern), their distribution within pallid sturgeon habitat, and their effects on pallid sturgeon at the landscape level. Extant water quality and analytical chemistry data from samples of river water, sediment, and sturgeon tissues from past studies, assessments, or monitoring activities throughout the species’ range were used to establish a list of contaminants. The list includes: metal and non-metal elements, pesticides, organic industrial chemicals, hormones, nutrients, and other potential water quality contaminants. Environmental samples collected from January 1, 2001 through December 31, 2014, when available, were used for all evaluations. This report is effectively a screening level hazard assessment whereby contituents of concern that may pose a potential harm to pallid sturgeon have been identified. These constituents of concern warrant further examination to determine the level of risk they pose to pallid sturgeon. The Assessment process was one of comparing the existing environmental data for individual constituents to reference values for adverse effects on fish specifically or aquatic life generally. The product of the Assessment is a simplified summary that is geographically organized by pallid sturgeon management unit that generally categorizes each individual contaminant or water quality constituent according to operationally defined levels of concern. This hazard assessment identifies potential constituents of concern to pallid sturgeon and may support prioritization for future data collection and research to enable a quantitative risk assessment. Regional data density at spatial and temporal scales notwithstanding, the Assessment points to some generalities in contaminant concerns within and across management units. Metals but not pesticides are the predominant contaminant of concern in the Great Plains Management Unit (GPMU). In the Central Lowlands Management Unit (CLMU), selenium exceeds benchmark levels. Triazine herbicides are potentially of concern in all but the GPMU. Concentrations of legacy contaminants such as PCBs and DDT and its metabolites exceeded benchmarks in samples from the CLMU, Interior Highlands Mangement Unit (IHMU), and Coastal Plains Management Unit (CPMU), but local and national trends indicate environmental levels of these contaminants continue to decline. Observed concentrations of nutrients and indicators of nutrient pollution were above benchmark levels throughout the pallid sturgeon’s range; however, the significance for pallid sturgeon health specifically is unknown. Almost no information exists on contemporary contaminants of concern such as the natural and synthetic estrogens (estradiol, ethinyl estradiol, and estrone) or polybrominated diphenyls (PBDEs). There are considerable informational data gaps for contaminants throughout the species’ range. Water quality measurements were the most frequent data encountered whereas, sediment and tissue data were orders of magnitude less frequent. The paucity of sediment and tissue concentrations, particularly the latter, prevents any meaningful conclusions regarding adverse effects of these contaminants on the growth and reproduction of pallid sturgeon. However, the Assessment could form the basis for regional workshops with subject matter specialists to develop plans to evaluate the contaminants most likely to affect pallid sturgeon health.

Missouri River basin, Mississippi River basin↗
USGS2009

Water Quality of Combined Sewer Overflows, Stormwater, and Streams, Omaha, Nebraska, 2006-07

The U.S. Geological Survey, in cooperation with the City of Omaha, investigated the water quality of combined sewer overflows, stormwater, and streams in the Omaha, Nebraska, area by collecting and analyzing 1,175 water samples from August 2006 through October 2007. The study area included the drainage area of Papillion Creek at Capeheart Road near Bellevue, Nebraska, which encompasses the tributary drainages of the Big and Little Papillion Creeks and Cole Creek, along with the Missouri River reach that is adjacent to Omaha. Of the 101 constituents analyzed during the study, 100 were detected in at least 1 sample during the study. Spatial and seasonal comparisons were completed for environmental samples. Measured concentrations in stream samples were compared to water-quality criteria for pollutants of concern. Finally, the mass loads of water-quality constituents in the combined sewer overflow discharges, stormwater outfalls, and streams were computed and compared. The results of the study indicate that combined sewer overflow and stormwater discharges are affecting the water quality of the streams in the Omaha area. At the Papillion Creek Basin sites, Escherichia coli densities were greater than 126 units per 100 milliliters in 99 percent of the samples (212 of 213 samples analyzed for Escherichia coli) collected during the recreational-use season from May through September (in 2006 and 2007). Escherichia coli densities in 76 percent of Missouri River samples (39 of 51 samples) were greater than 126 units per 100 milliliters in samples collected from May through September (in 2006 and 2007). None of the constituents with human health criteria for consumption of water, fish, and other aquatic organisms were detected at levels greater than the criteria in any of the samples collected during this study. Total phosphorus concentrations in water samples collected in the Papillion Creek Basin were in excess of the U.S. Environmental Protection Agency's proposed criterion in all but four stream samples (266 of 270). Similarly, only 2 of 84 Missouri River samples had total phosphorus concentrations less than the proposed criterion. The proposed total nitrogen criterion for the Corn Belt and Northern Great Plains ecoregion was surpassed in 80 percent of the water samples collected from the stream sites. Samples with total nitrogen concentrations greater than the proposed criterion were most common at Papillion Creek and Big Papillion Creek sites, where the proposed criterion was surpassed in 90 and 96 percent of the samples collected, respectively. Elevated concentrations of total nitrogen were less common at the Missouri River sites, with 33 percent of the samples analyzed having concentrations that surpassed the proposed nutrient criterion for total nitrogen. The three constituents with measured concentrations greater than their respective health-based screening levels were nickel, zinc, and dichlorvos. Differences in water quality during the beginning, middle, and end of the combined sewer overflow discharge and the stream hydrograph rise, peak, and recession were investigated. Concentrations from the ending part of the combined sewer overflow hydrograph were significantly different than those from the beginning and middle parts for 3 and 11 constituents, respectively. No constituents were significantly different between the beginning and middle parts of the combined sewer overflow discharge hydrograph. For the stream site upstream from combined sewer overflow outfalls on Cole Creek, the constituents with geometric mean values for the hydrograph rise that were at least twice those for the values of the peak and recession were specific conductance, magnesium, nitrite, N,N-diethyl-meta-toluamide (DEET), methyl salicylate, p-cresol, and Escherichia coli. Similarly, the constituents where the hydrograph peak was at least twice that for the rise and recession at the upstream Cole Creek site were total suspended solids, silver, an

Scientific Investigations Report↗
USGS1997

Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

Because of concerns expressed by the U.S. Congress and the environmental community, the Department of the Interior began a program in late 1985 to identify the nature and extent of water-quality problems induced by irrigation that might exist in the western States. Surface water, bottom sediment, and biota were collected from March through September 1995 along the lower Colorado River and in agricultural drains at nine sites in the Yuma Valley, Arizona, and analyzed for selected inorganic and organic constituents. Analyses of water, bottom sediment, and biota were completed to determine if irrigation return flow has caused, or has the potential to cause, harmful effects on human health, fish, and wildlife in the study area. Concentrations of dissolved solids in surface-water samples collected in March generally did not vary substantially from surface-water samples collected in June. Concentrations of dissolved solids ranged from 712 to 3,000 milligrams per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 500 milligrams per liter for drinking water. Concentrations of chloride in 9 of 18 water samples and concentrations of sulfate in 16 of 18 water samples exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 250 milligrams per liter for drinking water. Calcium and sodium were the dominant cations, and chloride and sulfate were the dominant anions. The maximum selenium concentration of 8 micrograms per liter exceeded the U.S. Environmental Protection Agency aquatic-life chronic criterion of 5 micrograms per liter. Concentrations of lead in 7 of 18 water samples and concentrations of mercury in 4 of 18 water samples exceeded the aquatic-life cronic criteria of 3.2 and 0.012 micrograms per liter, respectively. Concentrations of antimony, beryllium, cadmium, and silver in the water samples were below analytical reporting limits. Arsenic was detected in 3 of 9 bottom-sediment samples, and concentrations ranged from 11 to 16 micrograms per gram. Concentrations ofaluminum, beryllium, boron, copper, lead, and zinc were highest in samples from Main Drain at southerly international boundary near San Luis, Arizona. Selenium was detected in all bottom-sediment samples, and concentrations ranged from 0.1 to 0.7 micrograms per gram. Concentrations of cadmium, europium, homium, mercury, molybdenum, silver, tantalum, tin, and uranium were below analytical reporting limits in the bottom-sediment samples. Concentrations of trace elements in bottom-sediment samples were within the ranges found in a study of soils of the western United States and did not indicate a significant accumulation of these constituents. p,p'Dichlorodiphenyldichloroethylene (commonly referred to as p,-p'-DDE) was detected in one bottom-sediment sample at a concentration of 1.4 micrograms per gram. No other organochlorine compounds were detected in the bottom-sediment samples. DDE was present in all fish and bird samples. Almost one-half of the fish samples contained DDE residues that were two times higher than the mean calculated for a national study in 1984-85. Twenty-tree percent of the fish contained more than three times the national mean. Fish from downstream parts of the Main Drain had the highest concentrations of DDE. Although concentrations of DDE in fish and in bird carcasses and eggs were above background levels, residues generally were below thresholds associated with chronic poisoning and reproductive problems in figh and wildlife. Concentrations of 18 trace elements were detected in cattail (Typha sp.) roots, freshwater clam (Corbicula fluminea), fish, and bird samples. Selenium in most fish and in livers of red-winged (Agelaius phoeniceus) and yellow-headed (Xanthocephalus xanthocephalus) blackbirds was above background concentrations but below toxic concentrations. In contrast, selenium was present in a killdeer (Charadrium vociferus) liver sample at potentially toxic con

Water-Resources Investigations Report↗
USGS1997

Introduced species: A significant component of human-caused global change

Biological invasions are a widespread and significant component of human-caused global environmental change. The extent of invasions of oceanic islands, and their consequences for native biological diversity, have long been recognized. However, invasions of continental regions also are substantial. For example, more than 2,000 species of alien plants are established in the continental United States. These invasions represent a human-caused breakdown of the regional distinctiveness of Earth's flora and fauna—a substantial global change in and of itself. Moreover, there are well- documented examples of invading species that degrade human health and wealth, alter the structure and functioning of otherwise undisturbed ecosystems, and/or threaten native biological diversity. Invasions also interact synergistically with other components of global change. notably land use change. People and institutions working to understand, prevent, and control invasions are carrying out some of the most important—and potentially most effective—work on global environmental change.

New Zealand Journal of Ecology↗
USGS2012

Science implementation of Forecast Mekong for food and environmental security

Forecast Mekong is a significant international thrust under the Delta Research and Global Observation Network (DRAGON) of the U.S. Geological Survey (USGS) and was launched in 2009 by the U.S. Department of State and the Foreign Ministers of Cambodia, Laos, Thailand, and Vietnam under U.S. Department of State Secretary Hillary R. Clinton's Lower Mekong Initiative to enhance U.S. engagement with countries of the Lower Mekong River Basin in the areas of environment, health, education, and infrastructure. Since 2009, the USGS has worked closely with the U.S. Department of State; personnel from Cambodia, Laos, Thailand, and Vietnam; nongovernmental organizations; and academia to collect and use research and data from the Lower Mekong River Basin to provide hands-on results that will help decisionmakers in future planning and design for restoration, conservation, and management efforts in the Lower Mekong River Basin. In 2012 Forecast Mekong is highlighting the increasing cooperation between the United States and Lower Mekong River Basin countries in the areas of food and environmental security. Under the DRAGON, Forecast Mekong continues work in interactive data integration, modeling, and visualization system by initiating three-dimensional bathymetry and river flow data along with a pilot study of fish distribution, population, and migratory patterns in the Lower Mekong River Basin. When fully developed by the USGS, in partnership with local governments and universities throughout the Mekong River region, Forecast Mekong will provide valuable planning tools to visualize the consequences of climate change and river management.

Phnom Penh↗
USGS2017

Benefits of the fire mitigation ecosystem service in the Great Dismal Swamp National Wildlife Refuge, Virginia, USA

The Great Dismal Swamp (GDS) National Wildlife Refuge delivers multiple ecosystem services, including air quality and human health via fire mitigation. Our analysis estimates benefits of this service through its potential to reduce catastrophic wildfire related impacts on the health of nearby human populations. We used a combination of high-frequency satellite data, ground sensors, and air quality indices to determine periods of public exposure to dense emissions from a wildfire within the GDS. We examined emergency department (ED) visitation in seven Virginia counties during these periods, applied measures of cumulative Relative Risk to derive the effects of wildfire smoke exposure on ED visitation rates, and estimated economic losses using regional Cost of Illness values established within the US Environmental Protection Agency BenMAP framework. Our results estimated the value of one avoided catastrophic wildfire in the refuge to be \$3.69 million (2015 USD), or \$306 per hectare of burn. Reducing the frequency or severity of extensive, deep burning peatland wildfire events has additional benefits not included in this estimate, including avoided costs related to fire suppression during a burn, carbon dioxide emissions, impacts to wildlife, and negative outcomes associated with recreation and regional tourism. We suggest the societal value of the public health benefits alone provides a significant incentive for refuge mangers to implement strategies that will reduce the severity of catastrophic wildfires.

North Carolina, Virginia↗
USGS2011

Occurrence and distribution of pesticides in surface waters of the Hood River basin, Oregon, 1999-2009

The U.S. Geological Survey analyzed pesticide and trace-element concentration data from the Hood River basin collected by the Oregon Department of Environmental Quality (ODEQ) from 1999 through 2009 to determine the distribution and concentrations of pesticides in the basin's surface waters. Instream concentrations were compared to (1) national and State water-quality standards established to protect aquatic organisms and (2) concentrations that cause sublethal or lethal effects in order to assess their potential to adversely affect the health of salmonids and their prey organisms. Three salmonid species native to the basin are listed as "threatened" under the U.S. Endangered Species Act: bull trout, steelhead, and Chinook salmon. A subset of 16 sites was sampled every year by the ODEQ for pesticides, with sample collection targeted to months of peak pesticide use in orchards (March-June and September). Ten pesticides and four pesticide degradation products were analyzed from 1999 through 2008; 100 were analyzed in 2009. Nineteen pesticides were detected: 11 insecticides, 6 herbicides, and 2 fungicides. Two of four insecticide degradation products were detected. All five detected organophosphate insecticides and the one detected organochlorine insecticide were present at concentrations exceeding water-quality standards, sublethal effects thresholds, or acute toxicity values in one or more samples. The frequency of organophosphate detection in the basin decreased during the period of record; however, changes in sampling schedule and laboratory reporting limits hindered clear analysis of detection frequency trends. Detected herbicide and fungicide concentrations were less than water-quality standards, sublethal effects thresholds, or acute toxicity values. Simazine, the most frequently detected pesticide, was the only herbicide detected at concentrations within an order of magnitude (factor of 10) of concentrations that impact salmonid olfaction. Some detected pesticides are of concern, not for their toxicity alone, but for their ability to potentiate the harmful impacts of other pesticides, particularly organophosphates, on salmonids or their prey. Many samples contained mixtures of pesticides, but the effects to salmonids of relevant mixtures at environmentally realistic concentrations for the basin are unknown. Trace-element concentration data, although limited, indicate that eight trace elements are also of concern for their potential to harm salmonid health. The dataset is limited with regard to the spatial and seasonal distribution of pesticides and trace elements in all salmonid-bearing streams, the presence of particle-bound pesticides, and the presence of several unmonitored pesticides known to be used in the basin.

Oregon↗