Environmental Science › Water Science and Technology

Water Quality and Resources Studies

Works Count: 50820

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Description

This cluster of papers covers a wide range of topics related to water quality, hydrogeology, sediment analysis, and environmental impact assessment. It includes statistical methods for monitoring and analyzing water quality, as well as the use of various analytical techniques for chemical analysis. The papers also address the impact of human activities on water resources and provide guidelines for data reporting.

Keywords

Water Quality; Hydrogeology; Groundwater; Sediment Analysis; Surface Water; Statistical Methods; Monitoring; Environmental Impact; Chemical Analysis; Data Reporting

Site selection and collection of bridge-scour data in Delaware, Maryland, and Virginia

1993-01-01

Donald C. Hayes

Scour in stream channels is the leading cause of bridge failure.Accurate field measurements of scour are difficult to obtain because of the flow conditions at bridges during floods and the … Scour in stream channels is the leading cause of bridge failure.Accurate field measurements of scour are difficult to obtain because of the flow conditions at bridges during floods and the inability of existing measuring equipment to function under those conditions.This report describes criteria and methods that were developed by the U.S. Geological Survey to collect base-line data concerning the bridge structure, channel morphology, and bed material; and to collect streambed-profile and stream-velocity data during floods.Criteria were developed for selecting bridge sites to be monitored for scour during floods.Principal criteria defined for selection of a monitoring site were safety of personnel during measurements, accessibility of the site during floods, and accessibility of possible scour holes at abutments and piers.Fifteen bridge sites were selected for active bridge-scour data collection from more than 13,500 bridges spanning waterways in Delaware, Maryland, and Virginia.Bed-material characteristics are a principal explanatory variable to scour characteristics at a bridge site.Bed-material sampling procedures were developed to characterize the bed material of the channel near the bridge site.Grid-sample procedures were developed for gravel-bed channels, and bulk-sample procedures were developed for sand-bed channels.Structural information concerning bridge geometry was obtained from bridge plans and verified during the field survey.Channel geometry was surveyed at the approach section, the upstream side of the bridge, the downstream side of the bridge, and at the exit section.Standard streamflow-gaging equipment and procedures for defining streambed profiles and velocities near abutments and piers during floods were developed.Techniques to define streambed profiles using a fathometer also were developed.Comparison and limitations of the streambed profile defined by a sounding weight and fathometer are discussed.

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New reporting procedures based on long-term method detection levels and some considerations for interpretations of water-quality data provided by the U.S. Geological Survey National Water Quality Laboratory

1999-01-01

C.J. Childress , William T. Foreman , Brooke F. Connor +1 more

This report describes the U.S. Geological Survey National Water Quality Laboratory's approach for determining long-term method detection levels and establishing reporting levels, details relevant new reporting conventions, and provides preliminary … This report describes the U.S. Geological Survey National Water Quality Laboratory's approach for determining long-term method detection levels and establishing reporting levels, details relevant new reporting conventions, and provides preliminary guidance on interpreting data reported with the new conventions. At the long-term method detection level concentration, the risk of a false positive detection (analyte reported present at the long-term method detection level when not in sample) is no more than 1 percent. However, at the long-term method detection level, the risk of a false negative occurrence (analyte reported not present when present at the long-term method detection level concentration) is up to 50 percent. Because this false negative rate is too high for use as a default 'less than' reporting level, a more reliable laboratory reporting level is set at twice the determined long-term method detection level. For all methods, concentrations measured between the laboratory reporting level and the long-term method detection level will be reported as estimated concentrations. Non-detections will be censored to the laboratory reporting level. Adoption of the new reporting conventions requires a full understanding of how low-concentration data can be used and interpreted and places responsibility for using and presenting final data with the user rather than with the laboratory. Users must consider that (1) new laboratory reporting levels may differ from previously established minimum reporting levels, (2) long-term method detection levels and laboratory reporting levels may change over time, and (3) estimated concentrations are less certain than concentrations reported above the laboratory reporting level. The availability of uncensored but qualified low-concentration data for interpretation and statistical analysis is a substantial benefit to the user. A decision to censor data after they are reported from the laboratory may still be made by the user, if merited, on the basis of the intended use of the data.

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Design of the National Water-Quality Assessment Program; occurrence and distribution of water-quality conditions

1995-01-01

Robert J. Gilliom , William M. Alley , Martin E. Gurtz

The National Water-Quality Assessment Program assesses the status of and trends in the quality of the Nation's ground- and surface-water resources. The occurrence and distribution assessment component characterizes broad-scale water-quality … The National Water-Quality Assessment Program assesses the status of and trends in the quality of the Nation's ground- and surface-water resources. The occurrence and distribution assessment component characterizes broad-scale water-quality conditions in relation to major contaminant sources and background conditions in each study area. The surface-water design focuses on streams. The ground-water design focuses on major aquifers, with emphasis on recently recharged ground water associated with human activities.

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Water Quality Monitoring

1996-07-25

Richard Ballance , Jamie Bartram

In response to the coal ash spill at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant (KIF), TVA, the Tennessee Department of Environment and Conservation (TDEC) and the Environmental Protection … In response to the coal ash spill at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant (KIF), TVA, the Tennessee Department of Environment and Conservation (TDEC) and the Environmental Protection Agency (EPA) have collected surface water samples from the Emory, Clinch, and Tennessee Rivers.The objective of the surface water monitoring was to determine whether there was any immediate down-river migration of ashrelated constituents posing an imminent public health or environmental threat.Sampling was conducted at five Emory River, four Clinch River, and two Tennessee River locations.TVA sampled these locations two days per week and analyzed the samples for a 24 total and dissolved metals and total suspended solids.To monitor the effectiveness of best management practices to reduce ash migration during dredging, TVA performed daily monitoring of dredge plumes in the Emory River.TVA has collected more than 2,500 surface water samples since the spill.During the time-critical removal action, total arsenic in four Emory River surface water samples exceeded its Tennessee Domestic Water Supply Standard (TDWS) and Tennessee Water Quality Criterion (TWQC) of 0.01 mg/L.Dissolved copper exceeded the fish and aquatic life criterion in one sample at ERM 1.75.Total lead exceeded its TDWS in two Emory River samples at ERM 1.75.Thallium was detected in 64 samples, all of which exceeded its TWQC.This poster summarizes the results of TVA water quality monitoring a KIF during the period in which dredging of ash from the river was occurring.

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Hydrogeologic framework of the Floridan aquifer system in Florida and in parts of Georgia, Alabama, and South Carolina

1986-01-01

James A. Miller

For additional information, contact: Caribbean-Florida Water Science CenterU.S. Geological Survey3321 College AvenueDavie, FL 33314Contact Pubs Warehouse The Floridan aquifer system of the Southeastern United States is comprised of a thick … For additional information, contact: Caribbean-Florida Water Science CenterU.S. Geological Survey3321 College AvenueDavie, FL 33314Contact Pubs Warehouse The Floridan aquifer system of the Southeastern United States is comprised of a thick sequence of carbonate rocks that are mostly of Paleocene to early Miocene age and that are hydraulically connected in varying degrees. The aquifer system consists of a single vertically continuous permeable unit updip and of two major permeable zones (the Upper and Lower Floridan aquifers) separated by one of seven middle confining units downdip. Neither the boundaries of the aquifer system or of its component high- and low-permeability zones necessarily conform to either formation boundaries or time-stratigraphic breaks. The rocks that make up the Floridan aquifer system, its upper and lower confining units, and a surficial aquifer have been separated into several chronostratigraphic units. The external and internal geometry of these stratigraphic units is presented on a series of structure contour and isopach maps and by a series of geohydrologic cross sections and a fence diagram. Paleocene through middle Eocene units consist of an updip clastic facies and a downdip carbonate bank facies, that extends progressively farther north and east in progressively younger units. Upper Eocene and Oligocene strata are predominantly carbonate rocks throughout the study area. Miocene and younger strata are mostly clastic rocks. Subsurface data show that some modifications in current stratigraphic nomenclature are necessary. First, the middle Eocene Lake City Limestone cannot be distinguished lithologically or faunally from the overlying middle Eocene Avon Park 'Limestone.' Accordingly, it is proposed that the term Lake City be abandoned and the term Avon Park Formation be applied to the entire middle Eocene carbonate section of peninsular Florida and southeastern Georgia. A reference well section in Levy County, Fla., is proposed for the expanded Avon Park Formation. The Avon Park is called a 'formation' more properly than a 'limestone' because the unit contains rock types other than limestone. Second, like the Avon Park, the lower Eocene Oldsmar and Paleocene Cedar Keys 'Limestones' of peninsular Florida practically everywhere contain rock types other than limestone. It is therefore proposed that these units be referred to more accurately as Oldsmar Formation and Cedar Keys Formation. The uppermost hydrologic unit in the study area is a surficial aquifer that can be divided into (1) a fluvial sand-and-gravel aquifer in southwestern Alabama and westernmost panhandle Florida, (2) limestone and sandy limestone of the Biscayne aquifer in southeastern peninsular Florida, and (3) a thin blanket of terrace and fluvial sands elsewhere. The surficial aquifer is underlain by a thick sequence of fine clastic rocks and low-permeability carbonate rocks, most of which are part of the middle Miocene Hawthorn Formation and all of which form the upper confining unit of the Floridan aquifer system. In places, the upper confining unit has been removed by erosion or is breached by sinkholes. Water in the Floridan aquifer system thus occurs under unconfined, semiconfined, or fully confined conditions, depending upon the presence, thickness, and integrity of the upper confining unit. Within the Floridan aquifer system, seven low permeability zones of subregional extent split the aquifer system in most places into an Upper and Lower Floridan aquifer. The Upper Floridan aquifer, which consists of all or parts of rocks of Oligocene age, late Eocene age, and the upper half of rocks of middle Eocene age, is highly permeable. The middle confining units that underlie the Upper Floridan are mostly of middle Eocene age but may be as young as Oligocene or as old as early Eocene. Where no middle confining unit exists, the entire aquifer system is comprised of permeable rocks and for hydrologic discussions is treated as the Upper Floridan aquifer. The Lower Floridan aquifer contains a cavernous high-permeability horizon in the lower part of the early Eocene of south

Ground-Water Data-Collection Protocols and Procedures for the National Water-Quality Assessment Program: Collection and Documentation of Water-Quality Samples and Related Data

1995-01-01

Michael T. Koterba , Franceska D. Wilde , Wayne W. Lapham

Protocols for ground-water sampling are described in a report written in 1989 as part of the pilot program for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey … Protocols for ground-water sampling are described in a report written in 1989 as part of the pilot program for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). These protocols have been reviewed and revised to address the needs of the full-scale implementation of the NAWQA Program that began in 1991. This report, which is a collaborative effort between the NAWQA Program and the USGS Office of Water Quality, is the result of that review and revision. This report describes protocols and recommended procedures for the collection of water-quality samples and related data from wells for the NAWQA Program. Protocols and recommended procedures discussed include (1) equipment setup and other preparations for data collection; (2) well purging and field measurements; (3) collecting and processing ground-water-quality samples; (4) equipment decontamination; (5) quality-control sampling; and (6) sample handling and shipping.

Field guide for collecting and processing stream-water samples for the National Water-Quality Assessment Program

1994-01-01

L.R. Shelton

The U.S. Geological Survey's National Water-Quality Assessment program includes extensive data- collection efforts to assess the quality of the Nations's streams. These studies require analyses of stream samples for major … The U.S. Geological Survey's National Water-Quality Assessment program includes extensive data- collection efforts to assess the quality of the Nations's streams. These studies require analyses of stream samples for major ions, nutrients, sediments, and organic contaminants. For the information to be comparable among studies in different parts of the Nation, consistent procedures specifically designed to produce uncontaminated samples for trace analysis in the laboratory are critical. This field guide describes the standard procedures for collecting and processing samples for major ions, nutrients, organic contaminants, sediment, and field analyses of conductivity, pH, alkalinity, and dissolved oxygen. Samples are collected and processed using modified and newly designed equipment made of Teflon to avoid contamination, including nonmetallic samplers (D-77 and DH-81) and a Teflon sample splitter. Field solid-phase extraction procedures developed to process samples for organic constituent analyses produce an extracted sample with stabilized compounds for more accurate results. Improvements to standard operational procedures include the use of processing chambers and capsule filtering systems. A modified collecting and processing procedure for organic carbon is designed to avoid contamination from equipment cleaned with methanol. Quality assurance is maintained by strict collecting and processing procedures, replicate sampling, equipment blank samples, and a rigid cleaning procedure using detergent, hydrochloric acid, and methanol.

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Acid Deposition and the Acidification of Soils and Waters

1986-01-01

J. O. Reuss , D. W. Johnson

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of inorganic and organic constituents in water and fluvial sediments

1993-01-01

M. J. Fishman

Book 5, chapter Al, entitled Techniques of Water-Resources Investigations of the U.S. Geological Survey, contains methods used to analyze samples of water, suspended sediment, and bottom material for their content … Book 5, chapter Al, entitled Techniques of Water-Resources Investigations of the U.S. Geological Survey, contains methods used to analyze samples of water, suspended sediment, and bottom material for their content of inorganic and organic constituents. Technology continually changes, and so this laboratory manual includes new and revised methods for determining the concentration of dissolved constituents in water, whole water recoverable constituents in water-suspended sediment samples, and recoverable concentration of constituents in bottom material. Each method consists of the application, the principle of the method, interferences, the apparatus and reagents required, a detailed description of the analytical procedure, reporting results, units and significant figures, and analytical precision data. Included in this manual are 30 methods.

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Methods for collection and analysis of water samples

1960-01-01

F. H. Rainwater , L. L. Thatcher

This manual contains methods used by the U.S. Geological Survey to collect, preserve, and analyze water samples. Throughout, the emphasis is on obtaining analytical results that accurately describe the chemical … This manual contains methods used by the U.S. Geological Survey to collect, preserve, and analyze water samples. Throughout, the emphasis is on obtaining analytical results that accurately describe the chemical composition of the water in situ. Among the topics discussed are selection of sampling sites, frequency of sampling, field equipment, preservatives and fixatives, analytical techniques of water analysis, and instruments. Seventy-seven laboratory and field procedures are given for determining fifty-three water properties.

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The quality of our nation's waters: Nutrients in the nation's streams and groundwater, 1992-2004

2010-01-01

Neil M. Dubrovsky , Karen R. Burow , Gregory M. Clark +7 more

National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, … National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins.Do NAWQA findings substantiate national concerns for aquatic and human health?National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or "background" levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development.Nitrate concentrations above the Federal drinking-water standard—or Maximum Contaminant Level (MCL)—of 10 milligrams per liter (mg/L, as nitrogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public‑supply wells.Are levels of nutrients in water increasing or decreasing?A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation's most pristine streams warrants consideration.The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult.Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

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Guidelines and standard procedures for continuous water-quality monitors: Station operation, record computation, and data reporting

2006-01-01

Richard J. Wagner , R.W. Boulger , Carolyn J. Oblinger +1 more

The U.S. Geological Survey uses continuous water-quality monitors to assess the quality of the Nation's surface water. A common monitoring-system configuration for water-quality data collection is the four-parameter monitoring system, … The U.S. Geological Survey uses continuous water-quality monitors to assess the quality of the Nation's surface water. A common monitoring-system configuration for water-quality data collection is the four-parameter monitoring system, which collects temperature, specific conductance, dissolved oxygen, and pH data. Such systems also can be configured to measure other properties, such as turbidity or fluorescence. Data from sensors can be used in conjunction with chemical analyses of samples to estimate chemical loads. The sensors that are used to measure water-quality field parameters require careful field observation, cleaning, and calibration procedures, as well as thorough procedures for the computation and publication of final records. This report provides guidelines for site- and monitor-selection considerations; sensor inspection and calibration methods; field procedures; data evaluation, correction, and computation; and record-review and data-reporting processes, which supersede the guidelines presented previously in U.S. Geological Survey Water-Resources Investigations Report WRIR 00-4252. These procedures have evolved over the past three decades, and the process continues to evolve with newer technologies.

Ground water in freshwater-saltwater environments of the Atlantic Coast

2003-01-01

Paul M. Barlow

Pesticides in the Nation's Streams and Ground Water, 1992–2001

2006-01-01

Robert J. Gilliom , Jack E. Barbash , Charles G. Crawford +7 more

For additional information, contact: National Water-Quality Assessment ProgramU.S. Geological Survey413 National Center12201 Sunrise Valley DriveReston, Virginia 20192https://water.usgs.gov/nawqa/ This report is one of a series of publications, The Quality of Our … For additional information, contact: National Water-Quality Assessment ProgramU.S. Geological Survey413 National Center12201 Sunrise Valley DriveReston, Virginia 20192https://water.usgs.gov/nawqa/ This report is one of a series of publications, The Quality of Our Nation's Waters, that describe major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents evaluations of pesticides in streams and ground water based on findings for the first decadal cycle of NAWQA. 'Pesticides in the Nation's Streams and Ground Water, 1992-2001' greatly expands the analysis of pesticides presented in 'Nutrients and Pesticides,' which was the first report in the series and was based on early results from 1992 to 1995. Other reports in this series cover additional water-quality constituents of concern, such as volatile organic compounds and trace elements, as well as physical and chemical effects on aquatic ecosystems. Each report builds toward a more comprehensive understanding of regional and national water resources. The information in this series is intended primarily for those interested or involved in resource management, conservation, regulation, and policymaking at regional and national levels. In addition, the information might interest those at a local level who wish to know more about the general quality of streams and ground water in areas near where they live and how that quality compares with other areas across the Nation.

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Weighted Regressions on Time, Discharge, and Season (WRTDS), with an Application to Chesapeake Bay River Inputs1

2010-09-07

Robert M. Hirsch , Douglas Moyer , S. A. Archfield

Hirsch, Robert M., Douglas L. Moyer, and Stacey A. Archfield, 2010. Weighted Regressions on Time, Discharge, and Season (WRTDS), With an Application to Chesapeake Bay River Inputs. Journal of the … Hirsch, Robert M., Douglas L. Moyer, and Stacey A. Archfield, 2010. Weighted Regressions on Time, Discharge, and Season (WRTDS), With an Application to Chesapeake Bay River Inputs. Journal of the American Water Resources Association (JAWRA) 46(5):857‐880. DOI: 10.1111/j.1752‐1688.2010.00482.x Abstract: A new approach to the analysis of long‐term surface water‐quality data is proposed and implemented. The goal of this approach is to increase the amount of information that is extracted from the types of rich water‐quality datasets that now exist. The method is formulated to allow for maximum flexibility in representations of the long‐term trend, seasonal components, and discharge‐related components of the behavior of the water‐quality variable of interest. It is designed to provide internally consistent estimates of the actual history of concentrations and fluxes as well as histories that eliminate the influence of year‐to‐year variations in streamflow. The method employs the use of weighted regressions of concentrations on time, discharge, and season. Finally, the method is designed to be useful as a diagnostic tool regarding the kinds of changes that are taking place in the watershed related to point sources, groundwater sources, and surface‐water nonpoint sources. The method is applied to datasets for the nine large tributaries of Chesapeake Bay from 1978 to 2008. The results show a wide range of patterns of change in total phosphorus and in dissolved nitrate plus nitrite. These results should prove useful in further examination of the causes of changes, or lack of changes, and may help inform decisions about future actions to reduce nutrient enrichment in the Chesapeake Bay and its watershed.

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Laboratory theory and methods for sediment analysis

1969-01-01

Harold P. Guy

The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by … The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspended-sediment samples and the particle-size distribution of both suspended-sediment and bed-material samples. Other analyses related to these determinations may include particle shape, mineral content, and specific gravity, the organic matter and dissolved solids of samples, and the specific weight of soils. The merits and techniques of both the evaporation and filtration methods for concentration analysis are discussed. Methods used for particle-size analysis of suspended-sediment samples may include the sieve pipet, the VA tube-pipet, or the BW tube-VA tube depending on the equipment available, the concentration and approximate size of sediment in the sample, and the settling medium used. The choice of method for most bed-material samples is usually limited to procedures suitable for sand or to some type of visual analysis for large sizes. Several tested forms are presented to help insure a well-ordered system in the laboratory to handle the samples, to help determine the kind of analysis required for each, to conduct the required processes, and to assist in the required computations. Use of the manual should further 'standardize' methods of fluvial sediment analysis among the many laboratories and thereby help to achieve uniformity and precision of the data.

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U.S. "Mussel Watch" 1976-1978: an overview of the trace-metal, DDE, PCB, hydrocarbon and artificial radionuclide data

1983-08-01

John W. Farrington , Edward D. Goldberg , Robert W. Risebrough +2 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTU.S. "Mussel Watch" 1976-1978: an overview of the trace-metal, DDE, PCB, hydrocarbon and artificial radionuclide dataJohn W. Farrington, Edward D. Goldberg, Robert W. Risebrough, John H. Martin, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTU.S. "Mussel Watch" 1976-1978: an overview of the trace-metal, DDE, PCB, hydrocarbon and artificial radionuclide dataJohn W. Farrington, Edward D. Goldberg, Robert W. Risebrough, John H. Martin, and Vaughan T. BowenCite this: Environ. Sci. Technol. 1983, 17, 8, 490–496Publication Date (Print):August 1, 1983Publication History Published online1 May 2002Published inissue 1 August 1983https://pubs.acs.org/doi/10.1021/es00114a010https://doi.org/10.1021/es00114a010research-articleACS PublicationsRequest reuse permissionsArticle Views649Altmetric-Citations319LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Dominance statistics: Ordinal analyses to answer ordinal questions.

1993-11-01

Norman Cliff

Much behavioral rescarch involves comparing the central tendencies of different groups, or of the same subjects under different conditions, and the usual analysis is some form of mean comparison. This … Much behavioral rescarch involves comparing the central tendencies of different groups, or of the same subjects under different conditions, and the usual analysis is some form of mean comparison. This article suggests that an ordinal statistic, d, is often more appropriate. d compares the number of times a score from one group or condition is higher than one from the other, compared with the reverse. Compared to mean comparisons, d is more robust and equally or more powerful; it is invariant under transformation; and it often conforms more closely to the experimenter's research hypothesis. It is suggested that inferences from d be based on sample estimates of its variance rather than on the more traditional assumption of identical distributions

History of metal pollution in southern California coastal zone

1974-05-01

Kenneth W. Bruland , K.K. Bertine , Minoru Koide +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHistory of metal pollution in southern California coastal zoneKenneth W. Bruland, Kathe Bertine, Minoru Koide, and Edward D. GoldbergCite this: Environ. Sci. Technol. 1974, 8, 5, 425–432Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHistory of metal pollution in southern California coastal zoneKenneth W. Bruland, Kathe Bertine, Minoru Koide, and Edward D. GoldbergCite this: Environ. Sci. Technol. 1974, 8, 5, 425–432Publication Date (Print):May 1, 1974Publication History Published online1 May 2002Published inissue 1 May 1974https://pubs.acs.org/doi/10.1021/es60090a010https://doi.org/10.1021/es60090a010research-articleACS PublicationsRequest reuse permissionsArticle Views771Altmetric-Citations336LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

A Sediment Quality Triad: Measures of sediment contamination, toxicity and infaunal community composition in Puget Sound

1985-10-01

Edward R. Long , Peter M. Chapman

Phosphorus, Nitrogen, and Algae in Lake Washington after Diversion of Sewage

1970-08-14

W. T. Edmondson

After diversion of sewage effluent from Lake Washington, winter concentrations of phosphate and nitrate decreased at different rates. From 1963 to 1969, phosphate decreased to 28 percent of the 1963 … After diversion of sewage effluent from Lake Washington, winter concentrations of phosphate and nitrate decreased at different rates. From 1963 to 1969, phosphate decreased to 28 percent of the 1963 concentration, but nitrate remained at more than 80 percent of the 1963 value. Free carbon dioxide and alkalinity remained relatively high. The amount of phytoplanktonic chlorophyll in the summer was very closely related to the mean winter concentration of phosphate, but not to that of nitrate or carbon dioxide.

Environmental Impact Assessment: "Pseudoreplication" in Time?

1986-08-01

Allan Stewart‐Oaten , William W. Murdoch , Keith R. Parker

A recent monograph by Hurlbert raised several problems concerning the appropriate design of sampling programs to assess the impact upon the abundance of biological populations of, for example, the discharge … A recent monograph by Hurlbert raised several problems concerning the appropriate design of sampling programs to assess the impact upon the abundance of biological populations of, for example, the discharge of effluents into an aquatic ecosystem at a single point. Key to the resolution of these issues is the correct identification of the statistical parameter of interest, which is the mean of the underlying probabilistic "process" that produces the abundance, rather than the actual abundance itself. We describe an appropriate sampling scheme designed to detect the effect of the discharge upon this underlying mean. Although not guaranteed to be universally applicable, the design should meet Hurlbert's objections in many cases. Detection of the effect of the discharge is achieved by testing whether the difference between abundances at a control site and an impact site changes once the discharge begins. This requires taking samples, replicated in time, Before the discharge begins and After it has begun, at both the Control and Impact sites (hence this is called a BACI design). Care needs to be taken in choosing a control site so that it is sufficiently far from the discharge to be largely beyond its influence, yet close enough that it is influenced by the same range of natural phenomena (e.g., weather) that result in long—term changes in the biological populations. The design is not appropriate where local events cause populations at Control and Impact sites to have different long—term trends in abundance; however, these situations can be detected statistically. We discuss the assumptions of BACI, particularly additivity (and transformations to achieve it) and independence.

Model Assisted Survey Sampling

1992-01-01

Carl‐Erik Särndal , Bengt Swensson , Jan Wretman

Estimating the discharge of contaminants to coastal waters by rivers: Some cautionary comments

1985-12-01

Desmond E. Walling , B. Webb

Occurrence of sulfonylurea, sulfonamide, imidazolinone, and other herbicides in rivers, reservoirs and ground water in the Midwestern United States, 1998

2000-04-01

William A. Battaglin , Edward T. Furlong , Mark R. Burkhardt +1 more

Studying Dried, Stored Soil Samples — Some Pitfalls

1980-07-01

Richmond J. Bartlett , Bruce R. James

Abstract Dried, pulverized, and sieved soil samples are prepared and stored for laboratory research convenience. Drying and increasing time of storage both tend to push soil, which is metastable, toward … Abstract Dried, pulverized, and sieved soil samples are prepared and stored for laboratory research convenience. Drying and increasing time of storage both tend to push soil, which is metastable, toward increased surface acidity, reduced Mn, and increased solubility and oxidizability of soil organic matter. Reformation of metastable moist soil is a slow process mediated by environmental conditions interacting with life in the soil. Similar effects undoubtedly occur in the field as soils are dried. Two sets of problems confront the researcher using dried soil samples: those associated with drying itself and those associated with remoistening. The behavior of a dried sample immediately after adding water to it is different from that of the continuously moist soil. Remoistening for a longer period is followed by a microbiological explosion. The behavior of the soil for an extended period, perhaps more than a month after rewetting, may be anomalous, or at least unpredictable. Keeping a soil moist and aerobic, though certainly inconvenient, is the most satisfactory method of storage for many research uses.

The Connecticut Crackdown on Speeding: Time-Series Data in Quasi-Experimental Analysis

1968-08-01

Donald T. Campbell , H. Laurence Ross

Social research frequently encounters the task of evaluating change produced in nonrandomly selected groups by events which are beyond the researcher's control. The social scientist must verify that there has … Social research frequently encounters the task of evaluating change produced in nonrandomly selected groups by events which are beyond the researcher's control. The social scientist must verify that there has in fact been a change, and that the indicated event is its cause. Illustrations are manifold: a state terminates capital punishment, and proponents of this type of punishment predict an increase in the murder rate; a school is integrated, and supporters of the reform expect to find an increase in the positive self-evaluation of Negro pupils; a natural disaster occurs in a community, and altruistic behavior is expected to increase. Because in these situations the investigator has no control over the assignment of individuals or groups to “experimental” and “control” situations, the logic of the classical experiment must be reexamined in a search for optimal interpretative procedures.

The Iowa Articulation Norms Project and its Nebraska Replication

1990-11-01

Ann Bosma Smit , Linda Hand , J. Joseph Freilinger +2 more

The purpose of the Iowa Articulation Norms Project and its Nebraska replication was to provide normative information about speech sound acquisition in these two states. An assessment instrument consisting of … The purpose of the Iowa Articulation Norms Project and its Nebraska replication was to provide normative information about speech sound acquisition in these two states. An assessment instrument consisting of photographs and a checklist form for narrow phonetic transcription was administered by school-based speech-language pathologists to stratified samples of children in the age range 3–9 years. The resulting data were not influenced by the demographic variables of population density (rural/urban), SES (based on parental education), or state of residence (Iowa/Nebraska); however, sex of the child exerted a significant influence in some of the preschool age groups. The criteria used to determine acceptability of a production appeared to influence outcomes for some speech sounds. Acquisition curves were plotted for individual phoneme targets or groups of targets. These curves were used to develop recommended ages of acquisition for the tested speech sounds, with recommendations based generally on a 90% level of acquisition. Special considerations were required for the phonemes /n s z/.

Normalization and Elemental Sediment Contamination in the Coastal United States

1995-02-01

Kostas D. Daskalakis , Thomas P. O’Connor

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNormalization and Elemental Sediment Contamination in the Coastal United StatesKostas D. Daskalakis and Thomas P. O'ConnorCite this: Environ. Sci. Technol. 1995, 29, 2, 470–477Publication Date (Print):February 1, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNormalization and Elemental Sediment Contamination in the Coastal United StatesKostas D. Daskalakis and Thomas P. O'ConnorCite this: Environ. Sci. Technol. 1995, 29, 2, 470–477Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published inissue 1 February 1995https://pubs.acs.org/doi/10.1021/es00002a024https://doi.org/10.1021/es00002a024research-articleACS PublicationsRequest reuse permissionsArticle Views849Altmetric-Citations281LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

1995-01-01

Steven D. Zaugg , Mark W. Sandstrom , Steven G. Smith +1 more

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. … A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

A Working Model for the Variation in Stream Water Chemistry at the Hubbard Brook Experimental Forest, New Hampshire

1969-12-01

Noye M. Johnson , Gene E. Likens , Franz–Josef Bormann +2 more

Stream water chemistry varies hyperbolically with stream discharge through four decades of discharge change within the Hubbard Brook Experimental Forest, New Hampshire. This dilution process is most simply explained by … Stream water chemistry varies hyperbolically with stream discharge through four decades of discharge change within the Hubbard Brook Experimental Forest, New Hampshire. This dilution process is most simply explained by the mixing of rain water or surface water with deeper soil water. The resultant mixture of waters subsequently appears as stream water. Sodium and silica concentrations in stream water are markedly diluted during high discharge periods while hydrogen ion, aluminum, and nitrate concentrations are increased. Magnesium, calcium, sulfate, chloride and potassium concentrations are changed very little by stream discharge variations. During the summer, biologic activity measurably reduces the concentration of nitrate and potassium in stream water.

Fabricating data: How substituting values for nondetects can ruin results, and what can be done about it

2006-06-07

Dennis R. Helsel

The unequal variance t-test is an underused alternative to Student's t-test and the Mann–Whitney U test

2006-05-17

Graeme D. Ruxton

Often in the study of behavioral ecology, and more widely in science, we require to statistically test whether the central tendencies (mean or median) of 2 groups are different from … Often in the study of behavioral ecology, and more widely in science, we require to statistically test whether the central tendencies (mean or median) of 2 groups are different from each other on the basis of samples of the 2 groups. In surveying recent issues of Behavioral Ecology (Volume 16, issues 1–5), I found that, of the 130 papers, 33 (25%) used at least one statistical comparison of this sort. Three different tests were used to make this comparison: Student’s t-test (67 occasions; 26 papers), Mann–Whitney U test (43 occasions; 21 papers), and the t-test for unequal variances (9 occasions; 4 papers). My aim in this forum article is to argue for the greater use of the last of these tests. The numbers just related suggest that this test is not commonly used. In my survey, I was able to identify tests described simply as ‘‘t-tests’’ with confidence as either a Student’s t-test or an unequal variance t-test because the calculation of degrees of freedom from the 2 sample sizes is different for the 2 tests (see below). Hence, the neglect of the unequal variance t-test illustrated above is a real phenomenon and can be explained in several (nonexclusive ways) ways: 1. Authors are unaware that Student’s t-test is unreliable

Taking Serial Correlation into Account in Tests of the Mean

1995-02-01

Francis W. Zwiers , Hans von Storch

The comparison of means derived from samples of noisy data is a standard pan of climatology. When the data are not serially correlated the appropriate statistical tool for this task … The comparison of means derived from samples of noisy data is a standard pan of climatology. When the data are not serially correlated the appropriate statistical tool for this task is usually the conventional Student's t-test. However, frequently data are serially correlated in climatological applications with the result that the t test in its standard form is not applicable. The usual solution to this problem is to scale the t statistic by a factor that depends upon the equivalent sample size ne. It is shown, by means of simulations, that the revised t tea is often conservative (the actual significance level is smaller than the specified significance level) when the equivalent sample size is known. However, in most practical cases the equivalent sample size is not known. Then the test becomes liberal (the actual significance level is greater than the specified significance level). This systematic error becomes small when the true equivalent sample size is large (greater than approximately 30). The difficulties inherent in difference of means tests when there is serial dependence are reexamined. Guidelines for the application of the “usual” t test are provided and two alternative tests are proposed that substantially improve upon the “usual” t test when samples are small.

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Dividing the waters: governing groundwater in southern California

1993-06-01

William Blomquist

The Misuse of Ratios, Indices, and Percentages in Ecophysiological Research

1988-01-01

Gary C. Packard , Thomas J. Boardman

Ratios are used by many ecological physiologists to adjust (or scale) data that vary allometrically with body size. We use two sets of real data from our laboratory to illustrate … Ratios are used by many ecological physiologists to adjust (or scale) data that vary allometrically with body size. We use two sets of real data from our laboratory to illustrate in detail how investigators may be misled by statistical analyses performed on such ratios. The first example concerns the use of ratios to increase the precision of data gathered in planned experiments where body size varies within experimental groups but not among them. The second example concerns the use of ratios to remove confounding effects of body size from studies where animals in one group are larger than those in other groups, as a result either of the experimental manipulation itself or of the procedure for assigning animals to treatment groups. In both of these examples, statistical analyses of ratios lead to conclusions that are inconsistent with impressions gained from visual examinations of data displayed in bivariate plots. In comparison, analyses of covariance lead to conclusions that agree with impressions gained from these same plots. We therefore recommend that ecological physiologists discontinue using ratios to scale data and that they use the ANCOVA instead.

Environmental monitoring and assessment

2011-09-05

The quality of our nation's waters: Nutrients and pesticides

1999-01-01

This report is the first in a series of nontechnical publications, 'The quality of our nation's waters,' designed to describe major findings of the National Water-Quality Assessment Program regarding water-quality … This report is the first in a series of nontechnical publications, 'The quality of our nation's waters,' designed to describe major findings of the National Water-Quality Assessment Program regarding water-quality issues of regional and national concern. Sources, seasonal and geographic patterns of occurrence, and long-term trends are evaluated for nutrients and pesticides in streams and ground water and for pesticides in bed sediment and fish tissue from 20 major river basins and (or) aquifer systems across the conterminous United States. Implications of these national findings relative to water policies and strategies are presented. Issues discussed include relationships of nutrients and pesticides to natural features, land and chemical use, and resource-management practices; effects on human and aquatic health; considerations for development of water-quality standards; and approaches to modeling.

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WETLAND FUNCTIONS AND VALUES: THE STATE OF OUR UNDERSTANDING

1981-12-01

Statistical methods in water resources

2002-01-01

Dennis R. Helsel , Robert M. Hirsch

First posted September 1, 2002 For additional information, contact: Contact Pubs Warehouse PrefaceThis book began as class notes for a course we teach on applied statistical methods to hydrologists of … First posted September 1, 2002 For additional information, contact: Contact Pubs Warehouse PrefaceThis book began as class notes for a course we teach on applied statistical methods to hydrologists of the Water Resources Division, U. S. Geological Survey (USGS). It reflects our attempts to teach statistical methods which are appropriate for analysis of water resources data. As interest in this course has grown outside of the USGS, incentive grew to develop the material into a textbook. The topics covered are those we feel are of greatest usefulness to the practicing water resources scientist. Yet all topics can be directly applied to many other types of environmental data.This book is not a stand-alone text on statistics, or a text on statistical hydrology. For example, in addition to this material we use a textbook on introductory statistics in the USGS training course. As a consequence, discussions of topics such as probability theory required in a general statistics textbook will not be found here. Derivations of most equations are not presented. Important tables included in all general statistics texts, such as quantiles of the normal distribution, are not found here. Neither are details of how statistical distributions should be fitted to flood data -- these are adequately covered in numerous books on statistical hydrology.We have instead chosen to emphasize topics not always found in introductory statistics textbooks, and often not adequately covered in statistical textbooks for scientists and engineers. Tables included here, for example, are those found more often in books on nonparametric statistics than in books likely to have been used in college courses for engineers. This book points the environmental and water resources scientist to robust and nonparametric statistics, and to exploratory data analysis. We believe that the characteristics of environmental (and perhaps most other 'real') data drive analysis methods towards use of robust and nonparametric methods.Exercises are included at the end of chapters. In our course, students compute each type of analysis (t-test, regression, etc.) the first time by hand. We choose the smaller, simpler examples for hand computation. In this way the mechanics of the process are fully understood, and computer software is seen as less mysterious.We wish to acknowledge and thank several other scientists at the U. S. Geological Survey for contributing ideas to this book. In particular, we thank those who have served as the other instructors at the USGS training course. Ed Gilroy has critiqued and improved much of the material found in this book. Tim Cohn has contributed in several areas, particularly to the sections on bias correction in regression, and methods for data below the reporting limit. Richard Alexander has added to the trend analysis chapter, and Charles Crawford has contributed ideas for regression and ANOVA. Their work has undoubtedly made its way into this book without adequate recognition.Professor Ken Potter (University of Wisconsin) and Dr. Gary Tasker (USGS) reviewed the manuscript, spending long hours with no reward except the knowledge that they have improved the work of others. For that we are very grateful. We also thank Madeline Sabin, who carefully typed original drafts of the class notes on which the book is based. As always, the responsibility for all errors and slanted thinking are ours alone.

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Geochemical and sediment dynamics during an experimental high flow pulse event on the Allegheny River: Lessons for river system management

2025-06-25

Emily M. Elliott , Hailey Sinon , Abby J. Yancy +7 more | Biogeochemistry

Ecological Study Exploring Relationships between County Level Birth Defect Rates and Nitrate, Atrazine, and Other Nitrosatable Agrichemicals in Nebraska Groundwater

2025-06-13

Martha G. Rhoades , Alex A. Adjei , Debora Barnes–Josiah +4 more | ACS ES&T Water

Chorioallantoic Membrane of Northern Bobwhite (Colinus virginianus) as a Non-Lethal Method for Evaluating Forever Chemical Exposure to Avian Offspring

2025-06-12

Kenneth N Kikanme , Adcharee Karnjanapiboonwong , Angappan Rameshkumar +5 more | Environmental Toxicology and Chemistry

Abstract Per- and poly-fluoroalkyl substances (PFAS) are accumulative, persistent and pervasive environmental contaminants known to cause adverse effects in wildlife after prolonged exposure. Oviparous species, particularly during their embryonic development … Abstract Per- and poly-fluoroalkyl substances (PFAS) are accumulative, persistent and pervasive environmental contaminants known to cause adverse effects in wildlife after prolonged exposure. Oviparous species, particularly during their embryonic development stages, are highly susceptible to PFAS-related toxicity. Chronic exposure to these substances has been linked to bioaccumulation, resulting in arrested embryonic development, weakened immune responses, and reproductive defects in these animals. Traditional approaches, such as tissue chemical residue analysis, provide valuable insights into PFAS exposure but involve invasive methods, making them less viable for continuous monitoring. The chorioallantoic membrane (CAM) of bird embryos has emerged as a promising, non-invasive alternative for detecting persistent pollutants. In this regard, CAM samples were collected from hatched Northern Bobwhite (NOBO) eggs derived from reproductive toxicity experiments where females were exposed to PFAS-contaminated drinking water over varying durations. In one experiment, females were exposed for 60 days to a fire suppression foam containing perfluorobutanoic acid (PFBA) and perfluorohexanoic acid (PFHxA), while the second experiment involved 90-day exposure to perfluorooctane sulfonic acid (PFOS) alone and a mixture of PFOS and perfluorohexane sulfonic acid (PFHxS). Liquid chromatography-mass spectrometry (LC-MS) analysis revealed detectable but often unquantifiable levels of PFAS in CAM samples at low exposure concentrations. At higher exposure concentrations (20 ng/mL), yet still environmentally relevant, CAM analysis became more effective in providing an indication of PFAS exposure. These findings emphasize the potential utility of CAMs as a non-lethal method for assessing PFAS exposure in oviparous wildlife from certain scenarios and providing important insights into maternal transfer and transmembrane diffusion of PFAS from maternal tissue to hatchlings.

Pre-Removal Detention: Length, Conditions, and Oversight

2025-06-06

| University of Toronto Press eBooks

Qualitative and Quantitative Analysis of Highly-Polar Contaminants in Atlanta Urban Water

2025-06-01

Francesc Labad , Sandra Pérez | Analytica Chimica Acta

Turning Death Valley's arid air into a source of water

2025-06-01

A. L. Wilkins | The New Scientist

Talbert Channel and Huntington Beach Channel Sheet Pile Repairs, Orange County, California

2025-05-29

Satish Chilka , Victor Tirado , Craig Lewis | Ports 2022

DESIGN AND MANAGEMENT OF NATURAL AND NATURE BASED FEATURES CASE STUDIES IN SOUTHWEST FLORIDA, USA

2025-05-29

Mohamed A. Dabees | Coastal Engineering Proceedings

Natural disasters and coastal storms present an increasing threat for public safety and property damage in coastal communities. Climate and weather-related natural disasters have been on the rise in intensities … Natural disasters and coastal storms present an increasing threat for public safety and property damage in coastal communities. Climate and weather-related natural disasters have been on the rise in intensities and frequency over the past decades. The geography and exposure of the State of Florida to coastal storms necessitates development of coastal resiliency plans to manage and reduce the risk of flooding and damage due to coastal storms. Southwest Florida in particular, experienced increased frequency and intensity of tropical storms with multiple major hurricanes impacting the region over the past few decades. Recently, Hurricane Ian caused major catastrophic damages to the region in 2022 and Hurricane Idalia impacted the coastal areas with storm surge and waves as it passed through the Gulf of Mexico in 2023. This paper will discuss two examples of NNBF in Southwest Florida, their responses to tropical storms and the management efforts to maintain those features. Examples include Clam Bay Natural Resources Protection Area (NRPA) in Naples and The Tigertail Lagoon/ Sand Dollar Island Ecosystem in Marco Island (Dabees et al 2022).

MULTIVARIATE ANALYSIS FOR THE COMPOUND ASSESSMENT OF COASTAL STRUCTURES: THE MILFORD-ON-SEA (UK) CASE STUDY

2025-05-29

Antonio Francone , Gianfausto Salvadori , Fabrizio Durante +3 more | Coastal Engineering Proceedings

The assessment of sea structures is a critical endeavor in coastal engineering, ensuring the safety and sustainability of coastal developments and infrastructures. Effective management and protection of coastal areas require … The assessment of sea structures is a critical endeavor in coastal engineering, ensuring the safety and sustainability of coastal developments and infrastructures. Effective management and protection of coastal areas require reliable predictions of shoreline evolution when hard structures are present. In most cases, sea structure assessment involves dealing with both deterministic and random factors. Deterministic modeling is adopted to determine the shoreline response based on wave conditions, providing a baseline understanding on how the structure might behave under standard circumstances. However, the natural variability of the marine environment means that deterministic models alone are insufficient to capture the full range of possible scenarios. The present study addresses the inherent randomness in wave conditions by employing a stochastic technique to generate random sea states based on known parameters. This novel approach is applied to the coastal area of Milford-on-Sea, located in Hampshire (UK) where, in 2007, a field experiment was conducted involving the temporary installation of a 46-meter-long groyne.

Partnership for Safe Water Provides a Framework for Aurora Water's Success

2025-05-15

Amy Gahran

In the semiarid landscape of Aurora, Colo., where water scarcity is a growing challenge, Aurora Water has emerged as a model of excellence in water treatment and public health protection. … In the semiarid landscape of Aurora, Colo., where water scarcity is a growing challenge, Aurora Water has emerged as a model of excellence in water treatment and public health protection. Serving a city of 400,000 people, the utility operates three treatment plants and one distribution system, all of which have garnered awards for superior performance.

Thickening Impacts and Optimization when Transitioning to BNR -- Salt Lake Case Study

2025-05-04

C. Goss , Jose Rubalcaba , G. W. Davies +4 more

Proximity to, and Presence of, Golf Courses on Vulnerable and Non-vulnerable Groundwater Service Areas and Risk of Parkinson Disease in a Population-based Study (P2-5.005)

2025-04-07

Brittany Krzyzanowski , Aidan F. Mullan , E. Ray Dorsey +5 more

American Water (Excerpts)

2025-04-06

DAVID CHIN

ORGANIZATIONAL CAPACITY AND PERFORMANCE OF WATER PROJECTS IN MACHAKOS COUNTY

2025-04-04

Richard Orengo Odhiambo , Charles Rambo , Ngahu Catherine

Objective: This study examines the influence of organizational capacity on the performance of water projects in Machakos County, Kenya. Specifically, it investigates the role of resource mobilization, stakeholder collaboration, technical … Objective: This study examines the influence of organizational capacity on the performance of water projects in Machakos County, Kenya. Specifically, it investigates the role of resource mobilization, stakeholder collaboration, technical expertise, and monitoring and evaluation in shaping project outcomes. Theoretical Framework: The study is grounded in the resource-based view theory, which posits that an organization’s internal resources and capabilities determine its competitive advantage and performance. In regard to water projects, organizational capacity, comprising financial resources, human capital, and technical expertise acts as a critical determinant of project success. Method: A descriptive cross-sectional survey design was adopted, employing both qualitative and quantitative approaches. The study targeted 70 water projects in Machakos County, with data collected through structured questionnaires. The relationship between organizational capacity and project performance was analyzed using the ordinary least squares model. Results and Discussion: The findings indicate that organizational capacity has a significant positive effect on the performance of water projects. Strengthening technical expertise, fostering stakeholder collaboration, and improving resource mobilization enhance project success. However, weaknesses in monitoring and evaluation were identified as challenges to long-term project sustainability. Research Implications: The study highlights the importance of continuous training, collaboration, and structured resource mobilization frameworks for effective water project implementation. Policymakers should establish monitoring and evaluation mechanisms to enhance adaptability and sustainability. Managers should focus on capacity-building initiatives to improve project efficiency. Future research should explore longitudinal studies, compare urban and rural water projects, and use diverse metrics to measure organizational capacity and project performance. Originality/Value: This study contributes to the body of knowledge on water project management by providing empirical evidence on the role of organizational capacity. It offers practical recommendations for improving project implementation and sustainability while informing policy decisions on resource allocation and governance in the water sector.

Testing recreational waters for bacterial contamination in selected streams in Jefferson County WV

2025-04-04

B. L. Bayne , Peter B. Vila

BRAEDEN BAYNE and PETER VILA, Dept of Natural and Physical Sciences, Shepherd University, Shepherdstown, WV 25443. Testing recreational waters for bacterial contamination in selected streams in Jefferson County WV Three … BRAEDEN BAYNE and PETER VILA, Dept of Natural and Physical Sciences, Shepherd University, Shepherdstown, WV 25443. Testing recreational waters for bacterial contamination in selected streams in Jefferson County WV Three streams - Bullskin Run, Evitts Run, and Town Run - that flow through urban and rural areas were sampled for Escherichia coli (E. coli) contamination using IDEXX methodology. There was no significant difference between first order and mouth mainstem CFU/mL values and many samples exceeded the EPA criterion of 409 CFU/mL for lightly used waters with full body contact. In contrast, E. coli levels at a Town Run Spring were low (0-47 CFU/mL), indicating that groundwater bacterial levels are low and bacterial contamination in the mainstem originates from surface or shallow surface water inputs. Preliminary analysis indicates that the three watersheds differ in land cover: agriculture, forest, and urban/developed use. With varying land uses surrounding each of the stream locations microbial source tracking or a source determination study will be required to determine the source of bacterial contamination found in surface waters.

Flow through the Golden Horn Estuary

2025-04-02

B. Mutlu Sumer , V. Ş. Özgür Kırca

Arizona

2025-04-01

Davíd G. Martínez

The state of Arizona has struggled to reconcile its $1.3 billion deficit. To do so, the current governor, Katie Hobbs, has focused on education, decreasing the education budget by 5.8% … The state of Arizona has struggled to reconcile its $1.3 billion deficit. To do so, the current governor, Katie Hobbs, has focused on education, decreasing the education budget by 5.8% in baseline funding directed to the Arizona Department of Education and $239.8 million directed toward new educational initiatives. This manuscript provides an overview of the legislation related to P-20 funding, including Arizona’s funding priorities for P-12 and/or higher education, changes to the school funding formula, and the major human resources management initiatives funded through the new governor’s budget and several house and senate bills.

Constraining the Modern Hydrological Balance of Bear Lake, Utah‐Idaho: Insights From Stable Isotopes (δ18O and δ2H)

2025-04-01

Manuel Justin Custado , C. Gagnon , Bryce Belanger +6 more

Abstract Freshwater lakes are vital water resources, especially in the context of a changing climate. Supplementing existing hydrological methods to monitor lake levels may greatly improve resource management, particularly in … Abstract Freshwater lakes are vital water resources, especially in the context of a changing climate. Supplementing existing hydrological methods to monitor lake levels may greatly improve resource management, particularly in drought‐prone regions. In this study, we performed dual‐isotope (δ 18 O and δ 2 H) calculations to model the hydrological balance of Bear Lake, Utah‐Idaho. The lake is a critical water resource and site for paleoclimate studies of the latest Pleistocene. Using the Craig‐Gordon isotopic mass balance model, we simultaneously constrained unknown fluxes, including groundwater discharge and particularly evaporation, which is typically under‐constrained due to inconsistencies across existing methods. Data from community databases and sampling campaigns in 2022 and 2023 were utilized to derive an evaporation rate of 2.18 × 10 8 m 3 /yr (±4.94 × 10 6 m 3 /yr, 1σ using δ 18 O; ±3.47 × 10 6 m 3 /yr, 1σ using δ 2 H) at a calculated relative humidity of 0.62 above the lake. Detailed analysis of the sensitivity of the model revealed that parameters related to atmospheric moisture, particularly humidity and its isotopic composition, significantly influence evaporation estimates. Using carbonate‐based isotope data, we leveraged this sensitivity to provide insights in the evaporation and humidity at Bear Lake during different time periods. This study shows the potential of using modern water isotopic composition to aid with interpreting carbonate‐based paleoclimate data sets and informing current and future water resource management practices.

Identification of Contaminants in the Upper Basin of the Santa River: Implications for the Ecosystem

2025-03-13

Fray Masías Cruz Reyes , Miguel Comeca - Chuquipul , Angel Aronés - Cisneros +3 more

The study aimed to identify the main pollutants in the upper basin of the Santa (Ancash – Perú) River and evaluate their relationship with mining tailings and other sources of … The study aimed to identify the main pollutants in the upper basin of the Santa (Ancash – Perú) River and evaluate their relationship with mining tailings and other sources of contamination. Physical-chemical, inorganic, microbiological and parasitological parameters were analyzed at eight sampling points between the Negro River and Catac, using data from the National Water Authority (ANA) and comparing with the Environmental Quality Standards (ECA). The results revealed high levels of iron and aluminum at point 1, arsenic and chlorides at point 2, and bacteria such as Coliforms and E. coli at points 2 and 4, which implies a risk to public health and the ecosystem. It is concluded that constant monitoring and remediation measures are necessary in critical areas to protect water quality.

Age of Skarn Formation and Meteoric Water Infiltration in the Willsboro-Lewis Wollastonite District (Adirondack Highlands, New York)

2025-03-13

William H. Peck , Sean P. Regan , Tyler B. Blum +2 more

Abstract The Willsboro-Lewis wollastonite district occurs along the margin of the 1.15 Ga Marcy anorthosite massif in the Adirondack Highlands (New York), and records mineralogical and isotopic evidence for formation … Abstract The Willsboro-Lewis wollastonite district occurs along the margin of the 1.15 Ga Marcy anorthosite massif in the Adirondack Highlands (New York), and records mineralogical and isotopic evidence for formation in the anorthosite’s low-pressure metamorphic contact aureole. Wollastonite – garnet – pyroxene gneisses in the ~25 km long, 1.5 km thick skarn belt are mined for wollastonite, and are intercalated with massive garnetite and pyroxene ± garnet skarns, all of which have low oxygen isotope ratios indicating circulation of heated meteoric water and relatively shallow depths above the brittle-ductile transition during their formation. Anorthosite, skarns, and country rocks were all variably deformed and recrystallized at depths of 25-30 km during the 1.09–1.02 Ga Ottawan phase, and locally altered during the 1.01–0.98 Ga Rigolet phase, of the Grenvillian orogeny. This study examined rare zircon in low-δ18O skarn rocks to constrain the timing of surface-derived meteoric water infiltration. Zircon was dated and trace elements were measured by laser-ablation ICPMS, and oxygen isotopes were measured by ion microprobe, yielding a spectrum of ages and oxygen isotope ratios reflecting the polymetamorphic history of these rocks. Most samples are dominated by metamorphic zircon having Ottawan or Rigolet 207Pb/206Pb ages and are in high-temperature oxygen isotopic equilibrium with host wollastonite, garnet, and/or pyroxene. Several samples contain igneous zircon with disturbed U-Pb isotope systematics, reflecting some combination of new zircon growth and recrystallization during subsequent metamorphism. Relict 1150–1140 Ma ages are preserved in some zircon cores, which are taken as the ages of igneous zircon incorporated during skarn formation or from protoliths. Some of these 1150–1140 Ma cores preserve the low-δ18O record of interaction with meteoric water. Ages seen in the Willsboro-Lewis skarns reproduce the span of igneous, disturbed, and metamorphic ages in Adirondack anorthosite, and point to contemporaneous anorthosite emplacement, meteoric water circulation, and skarn formation at ca. 1150 Ma. This result is consistent with shallow emplacement of the Marcy anorthosite massif during crustal thinning related to the collapse of the 1.19–1.14 Ga Shawinigan orogeny, and that granulite facies overprinting was a later tectonic event.

Final Expansion of California's Celebrated Groundwater Replenishment Project

2025-03-13

James H. Clark , Jeff Neemann , Mehul Patel +1 more

Key Takeaways After two expansions since its opening in 2008, Southern California's Groundwater Replenishment System is at its goal capacity of 130 mgd. Through rigorous simulations and full‐scale testing, two … Key Takeaways After two expansions since its opening in 2008, Southern California's Groundwater Replenishment System is at its goal capacity of 130 mgd. Through rigorous simulations and full‐scale testing, two special districts determined the best materials, methods, and designs to overcome challenges to ensure peak performance from the expansion. Efficiencies gained with improved methods, advanced technologies, and reviving an old pipeline could save the districts millions in energy costs.

Colorado River

2025-03-12

Heather G. Lettner-Rust , Brent S. Roberts , Michael J. Mergen

Ground Water from Lower Cretaceous Rocks in Kansas

2025-02-06

Katherine M. Keene , Charles K. Bayne

Sandstones in Lower Cretaceous rocks contain supplies of water that may be adequate to meet increasing present and future demands for supplemental municipal and domestic use in central and western … Sandstones in Lower Cretaceous rocks contain supplies of water that may be adequate to meet increasing present and future demands for supplemental municipal and domestic use in central and western Kansas. An estimated 70 to 80 million acre-feet of water containing less than 1,000 milligrams per liter dissolved solids may be acceptable for use at the present (1976). An additional 10 to 15 million acre-feet containing 1,000 to 3,000 milligrams per liter dissolved solids is estimated to be available for use in the future with appropriate desalinization. Lower Cretaceous rocks crop out from Washington County on the north to Comanche County on the south. The rocks dip from a structural high in the southwest part of the State to structural lows in the northwest and north-central part. Depth below land surface increases generally northwestward to about 2,600 feet; thickness of the rocks increases westward from nearly zero to about 850 feet. The rocks consist chiefly of marine to nonmarine shale and siltstone interbedded with coastal to deltaic sandstone. The interbedded sandstone, which composes about one-third of the rocks, consists of one or more lenses that thicken westward to about 400 feet in the central part of western Kansas. The yield of water to individual wells is related to area] extent, thickness, and interconnection of the sand lenses and to grain size and cementation of the sand. Large amounts of water may be pumped by wells where loosely cemented sand lenses are interconnected. Wells commonly yield adequate supplies for domestic and stock use; reported yields from municipal and irrigation wells range from about 100 to 2,000 gallons per minute. Recharge to the Lower Cretaceous rocks occurs in the area of outcrop and from hydraulically connected saturated Cenozoic rocks, especially in the southern part of the State. Movement of water is principally northeastward from areas of recharge to areas of discharge where streams intersect the sandstone outcrops. Water in the sandstone aquifers commonly is confined between beds of relatively impermeable shale, causing water in wells to rise above the top of the aquifer. Water levels fluctuate in response to changes in atmospheric pressure, recharge, and discharge; greatest fluctuations result from discharge to wells for municipal and irrigation use. Progressive declines in water levels have occurred where irrigation withdrawals exceed recharge. Calcium bicarbonate water is dominant near recharge areas; mixed sodium and calcium bicarbonate water and sodium chloride water become successively dominant as the water moves downgradient from the recharge areas. The quality of water ranges from fresh to very saline (less than 1,000 to 35,000 milligrams per liter dissolved solids). In the areas of generally fresh water, localized areas of calcium sulfate water result from solution of gypsum in the Kiowa Formation, and areas of sodium chloride water result from contamination by oil-field brines.

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Great Lakes Coastal Wetlands Monitoring Program (EPA)

2025-02-03

Reply to Holliday et al. regarding the Carolina Bays

2025-01-25

Antonio Zamora

Turbidity more than herbivory, negatively correlated with Podostemum ceratophyllum Michx. stem length and biomass in slow water habitats in three Appalachian Plateau rivers.

2025-01-08

Ashley Vankirk , James L. N. Wood

The effects of environmental stressors (water chemistry, habitat characteristics, herbivory, etc.), on macrophytes are understudied and fewer studies have focused on how stressors impact macrophytes in swiftwater habitats. Podostemum ceratophyllum, … The effects of environmental stressors (water chemistry, habitat characteristics, herbivory, etc.), on macrophytes are understudied and fewer studies have focused on how stressors impact macrophytes in swiftwater habitats. Podostemum ceratophyllum, a swiftwater macrophyte native to Eastern North America, has been identified as a foundation species of Appalachian rivers because of the plant’s positive influence on macroinvertebrates, fish, and ecosystem processes. We initially sought to explore the effects of herbivory on the plant in three rivers in the Appalachian Plateau, however, we found little evidence of herbivory limiting Podostemum stem length and biomass. Instead, we observed that when Podostemum was exposed to low-flow conditions for approximately two weeks, stem length significantly decreased, and reduced stem length and plant biomass were correlated with turbidity in these rivers. Continued research exploring how environmental stressors influence Podostemum growth and survival could improve river management and support the conservation and restoration of the plant to eastern North American Rivers.