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At least 1,369 records · Page 76Linked to original sources
USGS2010

Endocrine active chemicals and endocrine disruption in Minnesota streams and lakes: Implications for aquatic resources, 1994-2008

The U.S. Geological Survey, in cooperation with St. Cloud State University, Minnesota Department of Health, Minnesota Pollution Control Agency, Minnesota Department of Natural Resources, Metropolitan Council Environmental Services, and the University of Minnesota, has conducted field monitoring studies and laboratory research to determine the presence of endocrine active chemicals and the incidence of endocrine disruption in Minnesota streams and lakes during 1994–2008. Endocrine active chemicals are chemicals that interfere with the natural regulation of endocrine systems, and may mimic or block the function of natural hormones in fish or other organisms. This interference commonly is referred to as endocrine disruption. Indicators of endocrine disruption in fish include vitellogenin (female egg yolk protein normally expressed in female fish) in male fish, oocytes present in male fish testes, reduced reproductive success, and changes in reproductive behavior. The results from a series of studies during 1994–2008 demonstrate that endocrine active chemicals are present in Minnesota surface waters, indicating that aquatic organism exposure is likely. Endocrine active chemicals have been identified in wastewater-treatment plant effluent and surface waters downstream from discharge of wastewater-treatment plant effluent throughout Minnesota at low concentrations. Biological indicators of endocrine disruption have been detected in wild fish throughout Minnesota at sites directly downstream from wastewater-treatment plant effluent, indicating that endocrine active chemicals in effluent contribute to endocrine disruption in fish. This finding was confirmed in a controlled study exposing fathead minnows to wastewater-treatment plant effluent at an onsite fish exposure laboratory. During this controlled study, changes in biological responses coincided with changes in wastewater-treatment plant effluent composition demonstrating that effluent effects on fish endocrine systems are temporally variable. Although chemicals contributing to endocrine disruption in fish are complex, several laboratory studies have further confirmed that certain classes of chemicals, such as hormones and alkylphenols, which are components of wastewater-treatment plant effluent, affect the endocrine systems of fish through biochemical, structural, and behavioral disruption. Although these studies indicate that wastewater-treatment plant effluent is a conduit for endocrine active chemicals to surface waters, endocrine active chemicals also were present in surface waters with no obvious wastewater-treatment plant effluent sources. Endocrine active chemicals were detected and indicators of endocrine disruption in fish were measured at numerous sites upstream from discharge of wastewater-treatment plant effluent. These observations indicate that other unidentified sources of endocrine active chemicals exist, such as runoff from land surfaces, atmospheric deposition, inputs from onsite septic systems, or other groundwater sources. Alternatively, some endocrine active chemicals may not yet have been identified or measured. The presence of biological indicators of endocrine disruption in male fish indicates that the fish are exposed to endocrine active chemicals. However indicators of endocrine disruption in male fish does not indicate an effect on fish reproduction or changes in fish populations.

Minnesota↗
USGS2011

Recommended methods for range-wide monitoring of prairie dogs in the United States

One of the greatest challenges for conserving grassland, prairie scrub, and shrub-steppe ecosystems is maintaining prairie dog populations across the landscape. Of the four species of prairie dogs found in the United States, the Utah prairie dog (Cynomys parvidens) is listed under the Endangered Species Act (ESA) as threatened, the Gunnison's prairie dog (C. gunnisoni) is a candidate for listing in a portion of its range, and the black-tailed prairie dog (C. ludovicianus) and white-tailed prairie dog (C. leucurus) have each been petitioned for listing at least once in recent history. Although the U.S. Fish and Wildlife Service (USFWS) determined listing is not warranted for either the black-tailed prairie dog or white-tailed prairie dog, the petitions and associated reviews demonstrated the need for the States to monitor and manage for self-sustaining populations. In response to these findings, a multi-State conservation effort was initiated for the nonlisted species which included the following proposed actions: (1) completing an assessment of each prairie dog species in each State, (2) developing a range-wide monitoring protocol for each species using a statistically valid sampling procedure that would allow comparable analyses across States, and (3) monitoring prairie dog status every 3-5 years depending upon the species. To date, each State has completed an assessment and currently is monitoring prairie dog status; however, for some species, the inconsistency in survey methodology has made it difficult to compare data year-to-year or State-to-State. At the Prairie Dog Conservation Team meeting held in November 2008, there was discussion regarding the use of different methods to survey prairie dogs. A recommendation from this meeting was to convene a panel in a workshop-type forum and have the panel review the different methods being used and provide recommendations for range-wide monitoring protocols for each species of prairie dog. Consequently, the Western Association of Fish and Wildlife Agencies (WAFWA), in coordination with USFWS and U.S. Geological Survey (USGS), hosted a prairie dog species survey methodology workshop January 25-28, 2010 in Fort Collins, Colorado. The workshop provided all WAFWA partners and interested parties the opportunity to present their survey methodology to a review panel made up of experts in the fields of quantitative biology, population biology, species biology, and biostatistics. This report presents the panel's survey methodology recommendations for each of the four species of prairie dogs found in the United States and, for the black-tailed prairie dog, a list of action items to facilitate implementation of the recommended methodology.

Scientific Investigations Report↗
USGS2014

Synthesis of studies in the fall low-salinity zone of the San Francisco Estuary, September-December 2011

In fall 2011, a large-scale investigation (fall low-salinity habitat investigation) was implemented by the Bureau of Reclamation in cooperation with the Interagency Ecological Program to explore hypotheses about the ecological role of low-salinity habitat in the San Francisco Estuary—specifically, hypotheses about the importance of fall low-salinity habitat to the biology of delta smelt Hypomesus transpacificus , a species endemic to the San Francisco Estuary and listed as threatened or endangered under federal and state endangered species legislation. The Interagency Ecological Program is a consortium of 10 agencies that work together to develop a better understanding of the ecology of the Estuary and the effects of the State Water Project and Federal Central Valley Project operations on the physical, chemical, and biological conditions of the San Francisco Estuary. The fall low-salinity habitat investigation constitutes one of the actions stipulated in the Reasonable and Prudent Alternative issued with the 2008 Biological Opinion of the U.S. Fish and Wildlife Service, which called for adaptive management of fall Sacramento-San Joaquin Delta outflow following “wet” and “above normal” water years to alleviate jeopardy to delta smelt and adverse modification of delta smelt critical habitat. The basic hypothesis of the adaptive management of fall low-salinity habitat is that greater outflows move the low-salinity zone (salinity 1–6), an important component of delta smelt habitat, westward and that moving the low-salinity zone westward of its position in the fall of recent years will benefit delta smelt, although the specific mechanisms providing such benefit are uncertain. An adaptive management plan was prepared to guide implementation of the adaptive management of fall low-salinity habitat and to reduce uncertainty. This report has three major objectives: • To provide a summary of the results from the first year of coordinated fall low-salinity habitat studies and monitoring. • To provide a synthesis of the results of the fall low-salinity habitat studies and other ongoing research and monitoring, to determine if the available information supports the hypotheses behind the adaptive management of fall low-salinity habitat as set forth in the adaptive management plan. • To begin to put the results from the fall low-salinity habitat studies into context within the larger body of knowledge regarding the San Francisco Estuary and, in particular, the upper San Francisco Estuary, including the Sacramento-San Joaquin Delta, Suisun Bay, and associated embayments. The basic approach of this report is to evaluate predictions derived from the hypotheses included in the conceptual model developed within the adaptive management plan. All available data from studies and monitoring conducted in fall 2011 and similar data from fall 2006, which was the most recent wet year preceding 2011, were considered. Data from 2005 and 2010 were also considered, to include the conditions antecedent to those years. Many of the predictions either could not be evaluated with the data available, or the needed data were not collected. Most of the predictions that could be addressed involved either the abiotic habitat components (that is, the physical environment) or delta smelt responses. In general, the fall low-salinity habitat investigation has been largely inconclusive as of the writing of this report. This is not to be unexpected in the first year of what is intended to be a multi-year adaptive-management effort. This report can be viewed as the first chapter of a “living document” that is to be continually updated as part of the adaptive management cycle. The results of this report, especially predictions with insufficient data for evaluation, indicate a number of science-based approaches to improve the fall low-salinity habitat investigations: • Develop a method of measuring “hydrodynamic complexity.” This concept is central to a number of the predictions that could not be evaluated. • Determine if wind speed warrants a stand-alone prediction. The wind-speed prediction is directly related to the turbidity predictions, and wind is only one of several factors important for determining turbidity. • Determine the correct spatial and temporal scale or scales necessary for monitoring and for studies to address the predicted abiotic and biotic responses. Many of the assessments in this report were based on monthly sampling of dynamic habitat components, such as phytoplankton and zooplankton populations, that can change on daily scales. • Address the nutrient predictions as part of developing a phytoplankton production model that includes nutrient cycling and other important processes, if feasible. At a minimum develop a mechanistic conceptual model to support more processed-based interpretations of data or design of new studies, rather than making simple predictions of increase or decrease. • Determine if studies of predation rates are feasible in areas where there are delta smelt.

California↗
USGS2015

Occurrence and trends of selected nutrients, other chemical constituents, diatoms, and cyanobacteria in bottom sediment, Lake Maxinkuckee, northern Indiana

Bottom-sediment cores collected in 2013 were used to investigate the recent and predevelopment (pre-1863) occurrence of selected nutrients (total nitrogen and total phosphorus), carbon, 39 trace elements, diatoms, cyanobacterial akinetes, and 3 radionuclides in the bottom sediment of Lake Maxinkuckee, a kettle lake in northern Indiana. Total nitrogen concentrations in the recent sediment (since about 1970) were variable with no consistent trend indicated. Total phosphorus concentrations in the recent sediment generally were uniform from about 1970 to about 2000 and indicated consistent inputs to the lake during that time. Subsequently, the history of total phosphorus deposition apparently was obscured by postdepositional upward diffusion. Trace-element concentrations in the bottom sediment of Lake Maxinkuckee generally were not cause for concern. Elevated concentrations of cadmium, copper, lead, mercury, and zinc in the recent sediment, compared to the predevelopment sediment, indicated likely human-related contamination; however, the trace-element concentrations were less than probable-effects guidelines (available for nine trace elements), which represent the concentrations above which toxic aquatic biological effects usually or frequently occur. Arsenic concentrations typically exceeded the threshold-effects guideline, which represents the concentration above which toxic aquatic biological effects occasionally occur, in the recent and predevelopment sediment. The arsenic likely originated from natural sources. Lead concentrations historically exceeded the threshold-effects guideline, but since had decreased below it in the recent sediment at most coring sites. The decreasing trend likely was indicative of the effect of the phase out of leaded gasoline. Biological indicators in the bottom sediment provided evidence for an improving, or at least not worsening, lake trophic condition. The occurrence of multiple diatom species, none of which were overwhelmingly dominant, was indicative of a minimally contaminated lake ecosystem. The combined evidence of several diatom species in the recent sediment indicated that the lake had not become more productive in recent decades. The combined evidence provided by akinetes for three cyanobacterial genera in the recent and predevelopment sediment indicated similar nutrient conditions in the lake during the past 40 years and possibly back to at least the mid-1800s.

Indiana↗
USGS2016

Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River—A synthesis of science, 2005 to 2012

This report is intended to synthesize the state of the scientific understanding of pallid sturgeon ecological requirements to provide recommendations for future science directions and context for Missouri River restoration and management decisions. Recruitment of pallid sturgeon has been low to non-existent throughout its range. Emerging understanding of the genetic structure of pallid sturgeon populations sets a broad framework for species and river management decisions, including decisions about managing the future genetic diversity of the species, but also decisions about where and what type of river restoration actions will be effective for subpopulations of this highly migratory species. Adult pallid sturgeon may migrate hundreds of kilometers (km) to spawn and their progeny may disperse even greater distances downstream as drifting free embryos. As a result of their complex life history pallid sturgeon naturally exploit a wide range of habitats during their life cycles. The construction of dams and reservoirs has fragmented habitats and may have shifted Missouri River subpopulations downstream. Research has not identified one primary biological or ecological constraint that appears to limit populations of the pallid sturgeon. With the present (2013) state of knowledge many life stages and life-stage transitions cannot be ruled out as contributing to recruitment failure. Biological opinions in 2000 (and amended in 2003) presented the dominant hypotheses for recruitment failure that existed at that time. Emphasis was on the role of the flow regime, specifically spring flow pulses (“spring rises”), to condition spawning substrate and cue reproductive aggregations and migrations, and on low flows and additional slow, shallow-water area to serve as rearing habitat for age-0 to juvenile pallid sturgeon. Studies on spawning habitat dynamics have documented that habitat patches selected for spawning by fish in the Lower Missouri River (Missouri River downstream from Gavins Point Dam to the confluence with the Mississippi River) are dominantly on outside, revetted bends in the deepest, fastest, and most turbulent water. Studies in more natural habitat on the Yellowstone River have documented spawning in convergent flow in the middle of the channel on discrete patches of gravel within a sand-dominated channel, an arrangement that may be more effective in attracting aggregations of reproductive fish compared to the nearly continuous revetment on the Lower Missouri River. Pallid sturgeon spawn in the spring and early summer during periods of increasing day length. Water temperature consistently exerts a threshold effect for spawning at 16–18 °C. In addition, the role of water temperature is indicated by pauses and reversals in upstream migrations that have been associated with cold weather fronts that create a transient decrease in water temperature. From 2005 to 2012 on the Lower Missouri River, no obvious relations between flow pulses and fish movements and spawning behaviors have been apparent. However, pallid sturgeon tracking at the Upper Missouri–Yellowstone confluence indicates that in most years, most telemetered pallid sturgeon migrate out of the Missouri River and into the Yellowstone River in the June–July timeframe in association with the spring pulse. This pattern was disrupted in 2011 when a high flow pulse with warm temperatures and high turbidity emanated from the Milk River, followed by record releases from Fort Peck Dam, and 36–39 percent of the telemetered population migrated up the Upper Missouri. This result supports the hypothesis that sufficiently large flow pulses may trigger migration and aggregation but it is not clear that functional pulses are within reservoir management authorities. Notably, a pallid sturgeon free embryo was captured on the Upper Missouri River in 2011 and another single, genetically confirmed embryo was captured on the Yellowstone River in 2012. Research on free-embryo drift has indicated the potential for hundreds of miles of downstream dispersal. Lack of distance to accommodate the extended downstream dispersal period of free embryos on the Upper Missouri and Yellowstone Rivers is the predominant hypothesis for recruitment failure in the upper basin. Long drift distances in the Lower Missouri River may be responsible for shifting Lower Missouri River sub-populations further into the Middle Mississippi River. Physical understanding of drift processes indicates that mean velocities could be slowed through decreased discharges or increased channel hydraulic radius (width and topographic diversity) to reduce free-embryo dispersal distances. In addition, the probability that free embryos are transported into and retained in channel-margin habitats is theoretically amenable to channel re-engineering that would increase cross-channel secondary currents in bends or channel expansions. Considerable uncertainty persists, however, about whether extended drift of Lower Missouri River larvae is responsible for recruitment failure. If drift distance is limiting, it is important to discern whether it would be advisable to retain larvae within the Missouri River, and where along the river restoration projects should be placed to optimize survival and growth of age-0 and juvenile sturgeon. Longitudinal differences in female pallid sturgeon fecundity lend support to the hypothesis that recruitment failure may be due, in part, to fish having insufficient nutrition to produce the numbers of gametes needed for the population to grow, perhaps because of simultaneous declines in prey-fish populations and their habitats. Establishing a chain of causality from habitat decline, to prey-fish populations, to sturgeon diets, to sturgeon fecundity, and to pallid sturgeon population growth presents a considerable scientific challenge. In addition to the dominant hypotheses relating pallid sturgeon populations to changes in flow regime and channel morphology, other factors have been identified that might be sources of stress and contribute to recruitment failure. Among these are water quality and contaminants. Ambient water-quality monitoring on the Missouri River has demonstrated summer episodes when dissolved oxygen dips below 5 milligrams per liter, a threshold that may be stressful especially to age-0 and juvenile sturgeon. Documented cases of intersex in shovelnose and pallid sturgeon indicate that agricultural and municipal sources of endocrine disrupting chemicals also may have a role in pallid sturgeon recruitment failure. Scientific understanding of the ecological requirements of pallid sturgeon has increased almost exponentially in the last two decades, and efforts are now turning from understanding fundamental biology of the species to quantifying how population dynamics relate to potential management actions. Progress in developing the science needed to inform management actions on the Missouri River may benefit from continuation of monitoring of reproductive cycles, reproductive movements, growth, and survival of telemetry tagged adults, increased emphasis on focused, complementary field and laboratory studies of factors influencing early life history, implementation of studies to resolve the role of food limitations in growth, survival, and reproductive condition, and implementation of studies designed specifically to parameterize models linking management to populations.

Missouri River↗
USGS2016

Proceedings of the 12th Biennial Conference of research on the Colorado Plateau

Introduction The Colorado Plateau is a physiographic region that encompasses 330,000 square kilometers in parts of four states in the southwestern United States (Colorado, Utah, New Mexico, and Arizona). Known for its high deserts, the Colorado Plateau also includes isolated mountains, high plateaus, and rugged canyons. Not only is the region topographically diverse, but geologically, biologically, and culturally diverse as well. The landscape is managed by Federal entities including the Bureau of Land Management, the National Park Service, and the U.S. Forest Service; Tribal nations including the Navajo Nation, Kaibab Paiute, Mountain Ute, Southern Ute, Hopi, Zuni, Hualapai, Havasupai, and White Mountain Apache Tribes; State land and wildlife management agencies; and privately owned holdings, creating complex interactions and management challenges. Population growth, increased tourism to Federal and State lands, and energy development have increased water demands and altered land-use patterns, and these changes have emerged as management challenges facing the people working and living in the region. Climate change, particularly the ongoing drought, has exacerbated the effects of population growth, land-use change, and other stressors such as invasive species. As managers seek solutions to the challenges facing the region’s natural and cultural resources, the Biennial Conference of Science and Management of the Colorado Plateau has become an important venue for exchanging information about emerging management concerns and recent scientific research. Each biennial conference has sought to promote discussion, information sharing, and productive communication among the managers, scientists, students, administrators, tribal representatives, and others who attend the conference with the goal of enhancing the use of the best available science to manage the region’s incomparable natural and cultural resources. The publication and dissemination of a conference proceedings series expands the reach of the conference beyond those people in attendance and creates a record on the research presented. The idea of producing a conference proceedings, and its subsequent publication, first occurred in 1993 following the first biennial conference in 1991. A published volume of contributed papers has followed each subsequent biennial conference, including this volume. The venue for publishing proceedings has changed over the years and has included the National Park Service, the Government Printing Office, the U.S. Geological Survey, and University of Arizona Press. Recently, van Riper and others (2015) published a compilation of the abstracts from the 11 previous conference proceedings. Collectively, the proceedings highlight approximately 25 years of natural- and cultural-resources research, promoting the integration of research with resource management across the Colorado Plateau. This volume is freely downloadable by the public, thereby further expanding the influence of this conference beyond the Colorado Plateau. The 12th Biennial Conference held in Flagstaff, Arizona, from September 16 to 19, 2013, covered a range of topics in the physical, biological, and socio-cultural sciences. The conference was organized and hosted by Northern Arizona University’s ( NAU) Merriam-Powell Center for Environmental Research, the Colorado Plateau Cooperative Ecosystem Studies Unit, and the U.S. Geological Survey Southwest Biological Science Center. Financial and in-kind support was provided by a wide range of organizations including the U.S. Forest Service, National Park Service, Bureau of Land Management, Grand Canyon Trust, Colorado Plateau Research Station, and various NAU entities. NAU sponsors include the Landscape Conservation Initiative, School of Forestry, School of Earth Science and Environmental Sustainability, Office of the Provost, and Office of the Vice President of Research. Contributors to these proceedings include researchers and managers from Federal, State, and Tribal governments, universities, private entities, and non-profit organizations. In this regard, this conference has wide-ranging support and participation among private and public entities involved in the science and management of natural resources on the Colorado Plateau.

Arizona, Colorado, New Mexico, Utah↗
USGS2016

Sediment oxygen demand in eastern Kansas streams, 2014 and 2015

Dissolved oxygen concentrations in streams are affected by physical, chemical, and biological factors in the water column and streambed, and are an important factor for the survival of aquatic organisms. Sediment oxygen demand (SOD) rates in Kansas streams are not well understood. During 2014 and 2015, the U.S. Geological Survey, in cooperation with the Kansas Department of Health and Environment, measured SOD at eight stream sites in eastern Kansas to quantify SOD rates and variability with respect to season, land use, and bottom-sediment characteristics. Sediment oxygen demand rates (SOD T ) ranged from 0.01 to 3.15 grams per square meter per day at the ambient temperature of the measurements. The summer mean SOD rate was 3.0-times larger than the late fall mean rate, likely because of increased biological activity at warm water temperatures. Given the substantial amount of variability in SOD rates possible within sites, heterogeneity of substrate type is an important consideration when designing SOD studies and interpreting the results. Sediment oxygen demand in eastern Kansas streams was correlated with land use and streambed-sediment characteristics, though the strength of relations varied seasonally. The small number of study sites precluded a more detailed analysis. The effect of basin land use and streambed sediment characteristics on SOD is currently (2016) not well understood, and there may be many contributing factors including basin influences on water quality that affect biogeochemical cycles and the biological communities supported by the stream.

Kansas↗
USGS2018

Hydrologic and water-quality characteristics of Caño Boquerón, Cabo Rojo, and Puerto Mosquito, Isla de Vieques, Puerto Rico, July 2015–July 2016

Coastal lagoons are common features of the Puerto Rico shoreline that provide habitat for commercial and recreational species and serve important roles in the nutrient cycle of the ecosystems. The U.S. Geological Survey, in cooperation with the Puerto Rico Environmental Quality Board, conducted a limnological study at Caño Boquerón in Cabo Rojo and at Puerto Mosquito on Isla de Vieques, Puerto Rico, to assess the principal mechanisms affecting the hydrology and water-quality characteristics of these coastal lagoons and provide baseline information to the regulatory agencies responsible for the management and conservation of these coastal waters and the preservation of their aquatic life. Field measurements and water samples were collected and processed during July 2015–July 2016 for analysis of physical, chemical, biological, and bacteriological characteristics. In addition, bathymetric surveys were made and sediment cores were collected in each lagoon to determine water volume and sediment deposition rate. Physicochemical properties assessed at Caño Boquerón indicated values were generally in compliance with Puerto Rico Environmental Quality Board standards; turbidity was occasionally slightly greater than the established standards, and dissolved oxygen concentration at bottom depths was lower than standards limits. Water transparency was evaluated through the Secchi disk method, and the average depth of disappearance was 1.0 meter (m) for Caño Boquerón and 1.9 m for Puerto Mosquito. Assessment of biological characteristics at both sites included primary productivity calculations as well as carbon production equivalents and monthly water sampling for bacteriological and nutrient analyses. For Caño Boquerón, gross plankton primary productivity averaged 3.38 grams of oxygen per cubic meter per day (gO 2 /m 3 -d); this value was computed as the sum of net phytoplankton primary productivity (0.74 gO 2 /m 3 -d) and plankton respiration (2.64 gO 2 /m 3 -d). Net community primary productivity averaged 1.44 gO 2 /m 3 -d, and the community respiration rate averaged 8.10 gO 2 /m 3 -d, which indicates that the biological community, aside from phytoplankton, acts as a net consumer rather than a net producer of biomass. In Puerto Mosquito, gross plankton primary productivity averaged 2.07 gO 2 /m 3 -d, of which 0.39 gO 2 /m 3 -d could be ascribed to net phytoplankton primary productivity, and 1.68 gO 2 /m 3 -d could be ascribed to plankton respiration. Diel studies conducted at Puerto Mosquito reflected an average net community primary productivity of 2.43 gO 2 /m 3 -d, and the average respiration rate was 6.72 gO 2 /m 3 -d. In a bathymetric survey conducted in August 2015, the water volume for the Caño Boquerón lagoon was calculated as 967,000 cubic meters (m 3 ), and the water volume at Puerto Mosquito was calculated as 1,182,200 m 3 , with an average depth of 1.5 m for Caño Boquerón and 1.8 m for Puerto Mosquito. The daily seawater exchange for Caño Boquerón and Puerto Mosquito was 13 and 5 percent of their water volumes referenced to mean sea level, respectively. A total of 20 sediment samples were processed and analyzed for cesium-137 ( 137 Cs) and lead-210 ( 210 Pb) radioisotopes. Analyses indicated that the sediment deposition rate at Caño Boquerón ranged from 0.32 to 0.36 centimeter per year, based on age dating analysis of 137 Cs and 210 Pb data; in Puerto Mosquito, the sediment deposition rate ranged from 0.26 to 0.27 centimeter per year, based on 137 Cs and 210 Pb data. Bacteriological analyses at Caño Boquerón and Puerto Mosquito indicated that fecal coliform and enterococci concentrations were below Puerto Rico Environmental Quality Board standards during the study. The highest concentrations of fecal coliform (22 colonies per 100 milliliters) and enterococci (9 colonies per 100 milliliters) at Caño Boquerón occurred in July, which coincided with the busiest season of vacation rentals near the lagoon. Bacteria concentrations were generally lower in Puerto Mosquito than in Caño Boquerón; maximum concentrations of fecal coliform and enterococci bacteria were measured in November 2015. The potential sources of contamination for Puerto Mosquito are limited, because it is within a conservation area.

Caño Boquerón, Cabo Rojo, Puerto Mosquito, Isla de↗
USGS2019

Sand Creek characterization study for Oncorhynchus clarkii virginalis (Rio Grande Cutthroat Trout), Great Sand Dunes National Park and Preserve, Colorado

The Oncorhynchus clarkii virginalis (Rio Grande cutthroat trout, RGCT) has undergone extensive declines in distribution and population. The RGCT is the southernmost distributed subspecies of cutthroat trout. Native to the Rio Grande Basin in Colorado and New Mexico, the subspecies is also found in the headwaters of the Pecos River and Canadian River basins in New Mexico. Currently, RGCT populations represent approximately 12 percent of the historic distribution. There are many factors that have contributed to the decline of the RGCT including small population sizes; hybridization with non-native salmonids; competition with non-native salmonids; angling; and loss of habitat resulting from wildfire, stream drying, disease, increased water temperatures; and poor land management. The eastern side of Colorado’s Rio Grande Basin is also home to Great Sand Dunes National Park and Preserve and the Sand Creek watershed. This study was designed to (1) characterize current physical and biological conditions of waterbodies within the Sand Creek watershed, from headwaters to lower terminus near the dune field; (2) characterize the spatial extent of existing fisheries within the Sand Creek watershed to inform the scope of potential future reclamation efforts; and (3) evaluate key limiting factors for a future native RGCT reintroduction. Bathymetric profiles were completed for two lakes within the upper Sand Creek drainage to characterize the physical geometry of each lake and to estimate the total lake volume required for future piscicide treatment and (or) fish removal efforts. Physical and biological conditions evaluated included stream water temperature and intermittency, discharge, and the genetics and existing fish community distribution and composition within the Sand Creek watershed were key components of this study. A baseline established the geographic extent and biological constraints factored into future piscicide treatment planning and native trout reintroduction efforts. As a result of this work, the Sand Creek watershed can be broken up into several distinct categories: Lakes that are good candidates for reclamation and reintroduction of RGCT, lakes that are poor candidates for reclamation, streams that currently have fish and are good candidates for reclamation and reintroduction, streams that currently lack fish and may be good candidates for introduction of RGCT, and streams that currently lack fish and are not good candidates for introduction of RGCT. This characterization study report is intended to inform State and Federal managers of the likelihood that the Sand Creek watershed can support a sustainable population of RGCT should they be reintroduced.

Colorado↗
USGS2023

Selenium hazards in the Salton Sea environment—Summary of current knowledge to inform future wetland management

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural, and energy production processes. The mobilization of selenium from shales through agricultural irrigation has been recognized since the 1930s; however, discovery of deformities in birds and other wildlife using agricultural habitats during the 1980s spurred studies to determine the extent and effects of the contamination. Through these early studies, researchers determined that biota in the Salton Sea drainage basin was at risk from legacy selenium contamination in the Colorado River watershed. The Salton Sea and its surrounding managed and unmanaged wetlands provide vital inland habitat and trophic support for diverse assemblages of resident and migratory wildlife, and understanding regional selenium hazards for these trust species is a priority for many Federal and State agencies. The modern Salton Sea is a shallow, landlocked saline lake in Riverside and Imperial Counties (not shown) of California that is sustained by irrigation return and perennial river inflow. Changes in water transfer agreements under the 2003 Quantification Settlement Agreement (QSA) have resulted in reduced irrigation flow, declining lake levels, and the evolution of unmanaged wetlands in areas where drains and rivers no longer reach the Salton Sea. These wetlands provide additional habitat for some species of concern, but their potential to increase selenium hazards for trust species is largely unknown. From the 1980s to 2020, efforts to document selenium contamination and effects throughout the region have resulted in a considerable amount of selenium data from the Salton Sea and its surrounding drainage basin; however, no long-term (greater than 20 years), consistent sampling program has been established, and all data have been collected by different entities using a variety of protocols and analytical techniques. This lack of coordination has been previously documented in regional management plans and has led to difficulty in reliably assessing selenium hazards in the Salton Sea environment. This report provides a summary of the available disparate selenium information collected from water, sediment, and biota in the Salton Sea region since the 1980s and to identify data gaps that need to be filled to understand the potential effects of selenium on species of concern, including federally endangered desert pupfish ( Cyprinodon macularius ) and Yuma Ridgway’s Rail ( Rallus obsoletus yumanensis; formerly Yuma Clapper Rail, Rallus longirostris yumanensis ). Available data from the Salton Sea drainage basin show that water from the Colorado River has the lowest selenium concentration of all surface water sources. All other surface water flowing into the Salton Sea has elevated selenium concentrations due to evaporation and evapotranspiration that occurs in agricultural fields and associated water delivery infrastructure or leaching of selenium from irrigated farmland soils. The Salton Sea has lower selenium concentrations because of various biogeochemical processes that recycle selenium into the sediment or volatilize it to the atmosphere; however, these mechanisms are not well defined, and it is not clear if selenium cycling will change in response to possible changes in the oxidation state of the Salton Sea bottom waters as water levels decline. Agricultural drains have the highest average selenium concentrations, but few drains have been sampled since changes in irrigation practices have occurred (due to the 2003 QSA). Groundwater selenium concentrations are variable; some wells south of the Salton Sea have selenium concentrations as high as 300 micrograms per liter (µg/L), whereas selenium concentrations are below detection in other wells. Groundwater and surface-water geothermal discharge zones around the margins of the Salton Sea and in unmanaged wetlands have not been studied in detail, and published selenium measurements are not available for these surface features. Selenium concentrations in the sediment of the Salton Sea drainage basin are highest in wetland particulate organic matter and the Salton Sea lakebed, indicating that removal of selenium from the water to the sediment has been a primary mechanism for keeping selenium concentrations low in the water column. Sediment selenium concentrations in wetlands are lower than in the Salton Sea but higher than inflowing drains and rivers, indicating the lentic wetland sites also may be important sinks for selenium because of biogeochemical processes. Sediment selenium data have not been collected in agricultural drains since changes in irrigation practices occurred (due to the 2003 QSA), and it is unknown if selenium sequestration from the water column has changed in these systems. We divided biological data into broad taxonomic categories, including primary producers, invertebrates, herpetofauna, mammals, fishes, and birds to facilitate evaluation of selenium concentrations and spatiotemporal trends observed in the Salton Sea. Overall, selenium concentrations were substantially greater in algae samples compared to all vascular plant samples combined. Median selenium concentrations in several invertebrate taxa (Chironomidae, Formicidae, Corixidae, Corbiculidae and Nereididae, and Decapoda) exceeded the maximum suggested dietary threshold of 3.0–4.0 micrograms per gram (µg/g) dry weight (dw) for predators consuming invertebrates in aquatic food webs. The greatest number of samples were collected from fish, and selenium distributions among species and locations showed that the range for most samples was lower than the U.S. Environmental Protection Agency selenium criterion for aquatic life (8.5 µg/g dw whole body, 11.3 µg/g dw fillets). The median selenium concentrations for whole body fish were below the selenium criterion in most locations, except for bairdiella ( Bairdiella icistia ) from the Salton Sea and irrigation drains, a few individual tilapia spp. (family Cichlidae, including genera Tilapia, Oreochromis , and their hybrids) from the river and river outlets, and several western mosquitofish ( Gambusia affinis ) and sailfin molly ( Poecilia latipinna ) from irrigation drain outlets. For avian samples combined among years and locations, median selenium concentrations in livers from all families except waders and Ibis (family Threskiornithidae) were higher than levels expected to cause selenium toxicosis (10–20 µg/g dw), and all median egg concentrations were above or near 6.0 μg/g dw, which is a conservative threshold value for reproductive impairment. Most knowledge gaps we identified for water, sediment, and biota were interrelated, and the use of integrated approaches to address knowledge gaps can provide greater insight into the drivers behind selenium hazards. Integrated water, sediment, and biota studies could help identify cost-effective management solutions that serve multiple purposes. A comprehensive analysis of the hydrology, biogeochemistry, and food-web processes in wetlands and other habitats can inform predictive models to identify drivers of selenium bioavailability, uptake from the environment and subsequent trophic transfer, ultimately forming the basis for experimental habitat management manipulations to minimize selenium hazards to wildlife. Furthermore, a comprehensive, long-term sampling and analytical laboratory plan would enable comparison of data among different entities that are sampling at the Salton Sea. Such efforts are well suited to help fill knowledge gaps that preclude understanding of selenium hazards and future management options for biota using Salton Sea habitats, including newly formed wetlands throughout the region. All data compiled for this report are available in two U.S. Geological Survey data releases: Groover and others (2022) for water and sediment samples and De La Cruz and others (2022) for biological samples. The data releases include all publicly available data for selenium concentrations in water, sediment, and biological samples collected in and around the Salton Sea, including the Coachella and Imperial Valleys. The data releases also include previously unpublished data.

California↗
USGS2002

Streamflow and water-quality data for selected watersheds in the Lake Tahoe basin, California and Nevada, through September 1998

The U.S. Geological Survey, in cooperation with the Tahoe Regional Planning Agency, and the University of California, Davis-Tahoe Research Group, has monitored tributaries in the Lake Tahoe Basin since 1988. This monitoring has characterized streamflow and has determined concentrations of nutrients and suspended sediment, which may have contributed to loss of clarity in Lake Tahoe. The Lake Tahoe Interagency Monitoring Program was developed to collect water-quality data in the basin. In 1998, the tributary-monitoring program included 41 water-quality stations in 14 of the 63 watersheds totaling half the area tributary to Lake Tahoe. The monitored watershed areas range from 1.08 square miles for First Creek to 56.5 square miles for the Upper Truckee River.Annual and unit runoff for 20 primary and secondary streamflow gaging stations in 10 selected watersheds are described. Water years 1988-98 were used to compare runoff data. The Upper Truckee River at South Lake Tahoe, Calif., had the highest annual runoff and Logan House Creek near Glenbrook, Nev., had the lowest. Blackwood Creek near Tahoe City, Calif., had the highest unit runoff and Logan House Creek had the lowest. The highest instantaneous peak flow was recorded at Upper Truckee River at South Lake Tahoe during the January 2, 1997, flood event.Certain water-quality measurements were made in the field. Ranges and median values of those measurements are described for 41 stations. Water temperature ranged from 0 to 23?C. Specific conductance ranged from 13 to 900 microsiemens per centimeter at 25?C. pH ranged from 6.7 to 10.6. Dissolved-oxygen concentrations ranged from 5.2 to 12.6 mg/L and from 70 to 157 percent of saturation.Loads, yields, and trends of nutrients and suspended sediment during water years 1988-98 at the streamflow gaging stations also are described. The Upper Truckee River at South Lake Tahoe had the largest median monthly load for five of the six measured nutrients and of suspended sediment, while Trout Creek at South Lake Tahoe had the largest median monthly load for the remaining nutrient. Logan House Creek near Glenbrook had the smallest median monthly loads for all nutrients and suspended sediment. Seasonal load summaries at selected stations showed nutrient and suspended-sediment loads were greatest in the spring months of April, May and June and least in the summer months of July, August, and September. Monthly load comparisons also were described for five watersheds with multiple stations.Incline Creek had the highest combined rank for all nutrients and sediment. Incline Creek had the largest monthly yields for dissolved nitrite plus nitrate nitrogen and soluble reactive phosphorus. Third Creek had the second highest combined rank and had the largest monthly yields for total nitrogen, total phosphorus, biologically reactive iron, and suspended sediment. Edgewood Creek had the largest monthly yield for dissolved ammonia nitrogen. Logan House Creek had the lowest combined rank and the smallest monthly yields for all nutrients and sediment.Trends in concentrations are either decreasing or not significant for all nutrients in all sampled watersheds, with the exception of biologically reactive iron. Biologically reactive iron and suspended sediment show an increasing trend in three watersheds and decreasing or no significant trend in the other seven watersheds.

Water-Resources Investigations Report↗
USGS1996

Influences of environmental settings on aquatic ecosystems in the Apalachicola-Chattahoochee-Flint River basin

The watershed boundary of the Apalachicola-Chattahoochee-Flint (ACF) River basin defines an aquatic ecosystem whose water quality is the result of complex interactions of natural and human influences on land and water resources. Topics relating to the basin's environmental setting-its physical, biological, and cultural characteristics-are summarized to provide an understanding of factors that influence water quality and the health of aquatic ecosystems. The ACF River basin lies partly in southwestern Georgia, southeastern Alabama, and northwestern Florida and covers 19,800 square miles in the Blue Ridge, the Piedmont, and the Coastal Plain Provinces. The basin includes the drainages of the Chattahoochee River and the Flint River, which meet to form the Apalachicola River. The Apalachicola River flows into the Gulf of Mexico at Apalachicola Bay. Basin hydrology and water quality are influenced by 16 mainstem reservoirs, 13 of which are on the Chattahoochee River. Ground water in the basin is contained in six aquifers-the surficial aquifer system, the Floridan aquifer system, the Claiborne aquifer, the Clayton aquifer, the Providence aquifer, and the crystalline-rock aquifer. Physiography, climate, and hydrology of the ACF River basin provide natural conditions that support a rich and abundant diversity of plants and animals. Although most of the ACF River basin has been altered by human activities, the basin's environment is noteworthy for its remaining biological diversity and the role it plays in sustaining biological productivity in Apalachicola Bay. The Bay produces 90 percent of Florida's and 13 percent of the Nation's oyster harvest; and functions as a nursery for penaeid shrimp, blue crabs, and a variety of fin fish. The diversity of the basin's aquatic fauna is noteworthy because the basin is home to (1) the largest number of fish species among Gulf Coast drainages east of the Mississippi River, (2) the largest assemblage of freshwater fish in Florida, (3) the largest number of mollusc species among western Florida drainages, and (4) the highest species density of amphibians and reptiles on the continent north of Mexico. Population of the ACF River basin in 1990 was estimated at 2.6 million. Nearly 90 percent of the total population lived in Georgia, and nearly 60 percent lived in the Metropolitan Atlanta area. The 1990 basin population is projected to increase by 15 percent to 3.0 million by the year 2000, and by 30 percent to 3.4 million by 2010. The largest increases in populations are projected for the Metropolitan Atlanta area. In 1972-76, approximately 59 percent of the basin was covered by forest, 29 percent was agricultural, 5 percent was wetland, 4 percent was urban, and 3 percent was water or barren land. Most of the original land cover of the basin has been transformed by human activity. Timber is the basin's largest cash crop and most forests consist of second-growth stands or large acreages of planted pine. The dominant agricultural land use in the Piedmont Province is pasture and confined feeding for dairy, livestock, and poultry production. Row-crop agriculture, orchards, and silviculture are most common in the Coastal Plain Province. The top five crops in order from most to least acres harvested in 1990 were peanuts, corn, soybeans, wheat, and cotton. The water in the basin is used for public and industrial supply, irrigation, power generation, navigation, and recreation. Although most public-supply withdrawals in the Blue Ridge and Piedmont Provinces are from surface-water sources, with the exception of counties near or immediately below the Fall Line, all publicly supplied water in the Coastal Plain is withdrawn from ground-water sources. Ground water supplied 18 percent of the basin's population served by public supply. Total water withdrawn in the ACF River basin in 1990 was 2,098 million gallons per day (Mgal/d), of which Georgia withdrew 82 percent and Florida and Alabama each withdrew 9 percent. Power generation is the single largest water use. Sixteen of the basin's 22 power generating plants are located along the mainstem of the Chattahoochee River. The U.S. Army Corps of Engineers maintains a navigation channel from the mouth of the Apalachicola River to Columbus, Ga., on the Chattahoochee River and to Bainbridge, Ga., on the Flint River. Water quality in the basin is influenced by the operation of 137 municipal wastewater-treatment facilities. In 1990, 354 Mgal/d of municipal wastewater was discharged within the ACF River basin. Eighty-eight percent of the wastewater was discharged into the Chattahoochee River basin, 10.6 percent into the Flint River basin, and 1.4 percent into the Apalachicola River basin. Two-thirds of the 938 stream miles in the Georgia portion of the ACF River basin having water quality that does not meet or only partially meets the designated-use criteria in the Chattahoochee River basin. The Chattahoochee River is the most heavily-used water resource both in the ACF River basin and in Georgia. Urban runoff or unknown nonpoint sources are cited as the causes of water-quality regulations in 72 percent of violations. The remaining causes primarily are combined sewer overflows in the Atlanta area, and discharges from municipal or industrial treatment facilities with inadequate treatment capabilities or operational deficiencies.

Alabama, Florida, Georgia↗
USGS1996

Instream investigations in the Beaver Creek Watershed in West Tennessee, 1991-95

The U.S. Geological Survey (USGS), in cooperation with the Tennessee Department of Agriculture, began a long-term scientific investigation in 1989 to evaluate the effect of agricultural activities on water quality and the effectiveness of agricultural best management practices in the Beaver Creek watershed, West Tennessee. In 1993 as a part of this study, the USGS, in cooperation with the Natural Resources Conservation Service, Shelby County Soil Conservation District, and the Tennessee Soybean Promotion Board, began an evaluation of the physical, chemical, biological and hydrological factors that affect water quality in streams and wetlands, and instream resource-management systems to treat agricultural nonpoint-source runoff and improve water quality. The purpose of this report is to present the results of three studies of stream and wetland investigations and a study on the transport of aldicarb from an agricultural field in the Beaver Creek watershed. A natural bottomland hardwood wetland and an artificially constructed wetland were evaluated as instream resource-management systems. These two studies showed that wetlands are an effective way to improve the quality of agricultural nonpoint-source runoff. The wetlands reduced concentrations and loads of suspended sediments, nutrients, and pesticides in the streams. A third paper documents the influence of riparian vegetation on the biological structure and water quality of a small stream draining an agricultural field. A comparison of the upper reach lined with herbaceous plants and the lower reach with mature woody vegetation showed a more stable biological community structure and Water- quality characteristics in the woody reach than in the herbaceous reach. The water-quality characteristics monitored were pH, temperature, dissolved oxygen, and specific conductance. The herbaceous reach had a greater diversity and abundance of organisms during spring and early summer, but the abundance dropped by approximately 85 percent during late summer. A fourth study describes the transport of aldicarb and its metabolites--aldicarb sulfoxide and aldicarb sulfone-in runoff at a small stream draining a cotton field. During 1991 to 1995, aldicarb and its metabolites were detected in runoff events. The highest concentrations occurred when aldicarb was applied to the field just hours before a rain storm. Aldicarb was not detectable in runoff a few weeks after application. The metabolites of aldicarb were detectable for 76 days after application. These studies demonstrate streambank vegetation and wetlands have a significant influence on stream water quality. The importance of weather conditions to herbicide application and runoff also is evident. This information can be used by resource managers to sustain and improve our Nation's streams for future generations.

Water-Resources Investigations Report↗
USGS1997

Distribution of fish, benthic invertebrate, and algal communities in relation to physical and chemical conditions, Yakima River basin, Washington, 1990

Biological investigations were conducted in the Yakima River Basin, Washington, in conjunction with a pilot study for the U.S. Geological Survey's National Water-Quality Assessment Program. Ecological surveys were conducted at 25 sites in 1990 to (1) assess water-quality conditions based on fish, benthic invertebrate, and algal communities; (2) determine the hydrologic, habitat, and chemical factors that affect the distributions of these organisms; and (3) relate physical and chemical conditions to water quality. Results of these investigations showed that land uses and other associated human activities influenced the biological characteristics of streams and rivers and overall water-quality conditions. Fish communities of headwater streams in the Cascades and Eastern Cascades ecoregions of the Yakima River Basin were primarily composed of salmonids and sculpins, with cyprinids dominating in the rest of the basin. The most common of the 33 fish taxa collected were speckled dace, rainbow trout, and Paiute sculpin. The highest number of taxa (193) was found among the inverte- brates. Insects, particularly sensitive forms such as mayflies, stoneflies, and caddisflies (EPT--Ephemeroptera, Plecoptera, and Trichoptera fauna), formed the majority of the invertebrate communities of the Cascades and Eastern Cascades ecoregions. Diatoms dominated algal communities throughout the basin; 134 algal taxa were found on submerged rocks, but other stream microhabitats were not sampled as part of the study. Sensitive red algae and diatoms were predominant in the Cascades and Eastern Cascades ecoregions, whereas the abundance of eutrophic diatoms and green algae was large in the Columbia Basin ecoregion of the Yakima River Basin. Ordination of physical, chemical, and biological site characteristics indicated that elevation was the dominant factor accounting for the distribution of biota in the Yakima River Basin; agricultural intensity and stream size were of secondary importance. Ordination identified three site groups and three community types. Site groups consisted of (1) small streams of the Cascades and Eastern Cascades ecoregions, (2) small streams of the Columbia Basin ecoregions, and (3) large rivers of the Cascades and Columbia Basin ecoregions. The small streams of the Columbia Basin could be further subdivided into two groups--one where agricultural intensity was low and one where agricultural intensity was moderate to high. Dividing the basin into these three groups removed much of the influence of elevation and facilitated the analysis of land-use effects. Community types identified by ordination were (1) high elevation, cold-water communities associated with low agricultural intensity; (2) lower elevation, warm-water communities associated with low agricultural intensity, and (3) lower elevation, warm-water communities associated with moderate to high agricultural intensity. Multimetric community condition indices indicated that sites in the Cascades and Eastern Cascades site group were largely unimpaired. In contrast, all but two sites in the Columbia Basin site group were impaired, some severely. Agriculture (nutrients and pesticides) was the primary factor responsible for this impairment, and all impaired sites were characterized by multiple indicators of impairment. Three sites (Granger Drain, Moxee Drain, and Spring Creek) had high levels of impairment. Sites in the large-river site group were moderately to severely impaired downstream from the city of Yakima. High levels of impairment at large-river sites corresponded with high levels of pesticides in fish tissues and the occurrence of external anomalies.

Washington↗
USGS1999

Water-resources-related information for the Oneida Reservation and vicinity, Wisconsin

Water-resources information has been compiled from 82 studies in which data were collected from the Oneida Reservation and vicinity. Forty-seven studies addressed surface-water issues, 33 studies addressed ground-water issues, and 23 studies addressed aquatic-biology issues. Some multidisciplinary studies are included in more than one category. Most of the surface-water studies summarized in this report included both water-quality and flow information. Several surface-water studies provided detailed short-term descriptions of surface- water quality and flow for parts of the Reservation and vicinity. Surface-water and stream-sediment quality data from several data bases have been compiled for this report. Most of the compiled data come from two sites on Duck Creek. Data from Duck Creek were analyzed for trends in concentrations of suspended sediment, dissolved nitrite plus nitrate, and dissolved atrazine. No trends were detected for any of these constituents. Trends in concentration of most constituents in surface-water samples were not calculated because of the short period of data collection at nearly all of the sites. Most of the ground-water reports that were identified included both quality and quantity and flow information. None of the ground-water studies provided a detailed description of ground-water quality for the Reservation as a whole. Several reports provide varied and detailed information for ground-water models that are useful for understanding hydrogeology and ground-water flow for the Reservation and vicinity. Ground-water quality data from 180 wells, compiled from several data bases, provided an incomplete summary of the condition of the drinking- water resources of the Reservation. Only 12 constituents, from a small number of wells, exceeded a USEPA drinking-water limit. Most of the exceedences were for trace metals and organics. No exceedences for pesticides or nitrate were reported; however, pesticide data were collected from only a small number of wells. Most of the aquatic biology studies described in this report include fish data, habitat data, or calculations of biotic index values, most of which comes from Duck Creek. Historical aquatic biology data for the Reservation and vicinity are limited. Most of the 23 studies described here were done since 1992. Most of the biota-quality data compiled for this report come from several sites on Duck Creek and represent a small number of samples. Results of the community survey regarding the water resources of the Oneida Reservation indicate that water usage by Tribal members today has declined when compared to the past. The most common reason given for the decline in usage was pollution. Most of those surveyed perceived Duck Creek as being "polluted," but about 50 percent thought that water quality in the Reservation was improving.

Wisconsin↗
USGS2000

Biodegradation of chlorinated ethenes at a karst site in middle Tennessee

This report presents results of field and laboratory investigations examining the biodegradation of chlorinated ethenes in a karst aquifer contaminated with trichloroethylene (TCE). The study site, located in Middle Tennessee, was selected because of the presence of TCE degradation byproducts in the karst aquifer and available site hydrologic and chlorinated-ethene information. Additional chemical, biological, and hydrologic data were gathered to evaluate whether the occurrence of TCE degradation byproducts in the karst aquifer was the result of biodegradation within the aquifer or simply transport into the aquifer. Geochemical analysis established that sulfate-reducing conditions, essential for reductive dechlorination of chlorinated solvents, existed in parts of the contaminated karst aquifer. Other areas of the aquifer fluctuated between anaerobic and aerobic conditions and contained compounds associated with cometabolism, such as ethane, methane, ammonia, and dissolved oxygen. A large, diverse bacteria population inhabits the contaminated aquifer. Bacteria known to biodegrade TCE and other chlorinated solvents, such as sulfate-reducers, methanotrophs, and ammonia-oxidizers, were identified from karst-aquifer water using the RNA-hybridization technique. Results from microcosms using raw karst-aquifer water found that aerobic cometabolism and anaerobic reductive-dechlorination degradation processes were possible when appropriate conditions were established in the microcosms. These chemical and biological results provide circumstantial evidence that several biodegradation processes are active in the aquifer. Additional site hydrologic information was developed to determine if appropriate conditions persist long enough in the karst aquifer for these biodegradation processes to be significant. Continuous monitoring devices placed in four wells during the spring of 1998 indicated that pH, specific conductance, dissolved oxygen, and oxidation-reduction potentials changed very little in areas isolated from active ground-water flow paths. These stable areas in the karst aquifer had geochemical conditions and bacteria conducive to reductive dechlorination of chlorinated ethenes. Other areas of the karst aquifer were associated with active ground-water flow paths and fluctuated between anaerobic and aerobic conditions in response to rain events. Associated with this dynamic environment were bacteria and geochemical conditions conducive to cometabolism. In summary, multiple lines of evidence developed from chemical, biological, and hydrologic data demonstrate that a variety of biodegradation processes are active in this karst aquifer.

Tennessee↗
USGS2015

Dust control products at Hagerman National Wildlife Refuge, Texas: environmental safety and performance

Controlling fugitive dust while protecting natural resources is a challenge faced by all managers of unpaved roads. Unfortunately, road managers choosing between dust control products often have little objective environmental information to aid their decisions. To address this information gap, the U.S. Geological Survey and the U.S. Fish and Wildlife Service collaborated on a field test of three dust control products with the objectives of ( a ) evaluating product performance under real-world conditions, ( b ) verifying the environmental safety of products identified as practically nontoxic in laboratory tests, and ( c ) testing the feasibility of several environmental monitoring techniques for use in dust control tests. In cooperation with refuge staff and product vendors, three products (one magnesium chloride plus binder, one cellulose, and one synthetic fluid plus binder) were applied in July 2012 to replicated road sections at the Hagerman National Wildlife Refuge in Texas. These sections were monitored periodically for 12 months after application. Product performance was assessed by mobile-mounted particulate-matter meters measuring production of fugitive dust and by observations of road conditions. Environmental safety was evaluated through on-site biological observations and leaching tests with samples of treated aggregate. All products reduced dust and improved surface condition during those 12 months. Planned environmental measurements were not always compatible with day-to-day refuge management actions; this incompatibility highlighted the need for flexible biological monitoring plans. As one of the first field tests of dust suppressants that explicitly incorporated biological endpoints, this effort provides valuable information for improving field tests and for developing laboratory or semifield alternatives.

Texas↗
USGS1998

Cadmium resistance in an oligochaete and its effect on cadmium trophic transfer to an omnivorous shrimp

It has been demonstrated that the deposit-feeding oligochaete Limnodrilus hoffmeisteri inhabiting Foundry Cove (FC), a severely cadmium (Cd)-contaminated cove located on the Hudson River, New York, USA, has evolved resistance to Cd. In this study we investigate how this resistance influences Cd trophic transfer from this oligochaete to the grass shrimp Palaemonetes pugio. Cadmium-resistant worms collected from FC and nonresistant worms collected from an adjacent unpolluted site were investigated for differences in Cd tolerance, accumulation, subcellular distribution and bioavailability to shrimp. FC worms were more tolerant of Cd, surviving twice as long as worms from the unpolluted site during a toxicity bioassay. The 7 d concentration factor of Cd-resistant worms was 4 times greater than that of nonresistant worms (2020 vs 577). There were also differences between worm populations with respect to subcellular Cd distributions. Cd-resistant worms produced metallothionein-like proteins (MT) as well as metal-rich granules (MRG) for Cd storage and detoxification; nonresistant worms only produced MT. These differences in subcellular Cd distributions led to large differences in Cd bioavailability to shrimp; shrimp fed Cd-resistant worms absorbed 21% of the ingested Cd, while those fed nonresistant worms absorbed roughly 4 times that amount (~75%). These absorption efficiencies were in good agreement with the proportions of Cd bound to the worm's most biologically available subcellular fractions (i.e. the cytosol and organelles). Although Cd-resistant worms predominantly stored the toxic metal in biologically unavailable MRG, their increased accumulation of Cd would still result in substantial trophic transfer to shrimp because of the storage of Cd in the biologically available fractions. This work demonstrates that the evolution of Cd resistance can have profound implications for Cd bioavailability and cycling within aquatic ecosystems.

Marine Ecology Progress Series↗