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Verlin C Stephens - One of the best experts on this subject based on the ideXlab platform.
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the effects of land use on fluvial Sediment Chemistry for the conterminous u s results from the first cycle of the nawqa program trace and major elements phosphorus carbon and sulfur
Science of The Total Environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited ( or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
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The effects of land use on fluvial Sediment Chemistry for the conterminous U.S. - results from the first cycle of the NAWQA Program: trace and major elements, phosphorus, carbon, and sulfur.
The Science of the total environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited (or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
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The effects of land use on fluvial Sediment Chemistry for the conterminous U.S. — Results from the first cycle of the NAWQA Program: Trace and major elements, phosphorus, carbon, and sulfur
Science of The Total Environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited ( or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
Arthur J Horowitz - One of the best experts on this subject based on the ideXlab platform.
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the effects of land use on fluvial Sediment Chemistry for the conterminous u s results from the first cycle of the nawqa program trace and major elements phosphorus carbon and sulfur
Science of The Total Environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited ( or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
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The effects of land use on fluvial Sediment Chemistry for the conterminous U.S. - results from the first cycle of the NAWQA Program: trace and major elements, phosphorus, carbon, and sulfur.
The Science of the total environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited (or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
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The effects of land use on fluvial Sediment Chemistry for the conterminous U.S. — Results from the first cycle of the NAWQA Program: Trace and major elements, phosphorus, carbon, and sulfur
Science of The Total Environment, 2008Co-Authors: Arthur J Horowitz, Verlin C StephensAbstract:In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed Sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed Sediment samples were collected. All samples were size-limited ( or=95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on Sediment Chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (
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Effects of Hurricanes Katrina and Rita on the Chemistry of bottom Sediments in Lake Pontchartrain, La.
Circular, 2007Co-Authors: Peter C. Van Metre, Barbara J. Mahler, Arthur J Horowitz, William T. Foreman, Christopher C. Fuller, Mark R. Burkhardt, Kent A. Elrick, Edward T. Furlong, Stanley C. Skrobialowski, James J. SmithAbstract:The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the Sediment Chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom Sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom Sediments exceeded median concentrations in U.S. urban lakes and Sediment-quality guidelines. The extent of the elevated concentrations was limited, however, to within a few hundred meters of the mouth of the 17th Street Canal, similar to results of historical assessments. Chemical and radionuclide analysis of pre- and post-Hurricane Rita samples indicates that remobilization of near-shore Sediment by lake currents and storms is an ongoing process. The effects of Hurricanes Katrina and Rita on the Sediment Chemistry of Lake Pontchartrain are limited spatially and are most likely transitory.
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Effects of hurricanes Katrina and Rita on the Chemistry of bottom Sediments in Lake Pontchartrain, Louisiana, USA
Environmental science & technology, 2006Co-Authors: Peter C. Van Metre, Barbara J. Mahler, Arthur J Horowitz, William T. Foreman, Christopher C. Fuller, Mark R. Burkhardt, Kent A. Elrick, Edward T. Furlong, Stanley C. Skrobialowski, James J. SmithAbstract:The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the Sediment Chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom Sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom Sediments exceeded median concentrations in U.S. urban lakes and Sediment-quality guidelines. The extent of the elevated concentrations was limited, however, to within a few hundred meters of the mouth of the 17th Street Canal, similar to results of historical assessments. Chemical and radionuclide analysis of pre- and post-Hurricane Rita samples indicates that remobilization of near-shore Sediment by lake currents and storms is an ongoing process. The effects of Hurricanes Katrina and Rita on the Sediment Chemistry of Lake Pontchartrain are limited spatially and are most likely transitory.
Kathy Welch - One of the best experts on this subject based on the ideXlab platform.
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revision of Sediment quality triad indicators in puget sound washington usa i a Sediment Chemistry index and targets for mixtures of toxicants
Integrated Environmental Assessment and Management, 2013Co-Authors: Edward R. Long, Margaret Dutch, Valerie Partridge, Sandra Weakland, Kathy WelchAbstract:The Washington State Department of Ecology annually conducts Sediment quality monitoring in Puget Sound as a component of the Puget Sound Ecosystem Monitoring Program. Sediment samples are analyzed to determine the concentrations of about 170 chemical and physical variables. A Sediment Chemistry Index (SCI) was derived using the State of Washington Sediment Management Standards to account for the presence and concentrations of mixtures of toxicants. Mean Sediment Quality Standard quotients (mSQSq) were calculated as the basis for the SCI and compared to the incidence and degree of toxicity in laboratory tests and to metrics of the diversity and abundance of resident benthic assemblages in a database consisting of as many as 664 samples. These data were evaluated with co-occurrence analyses to identify “cut points” (i.e., thresholds) in the index below which the frequency and magnitude of biological effects were relatively low and above which they occurred with increasing frequency or magnitude. Iterative trials of different sets of cut points established the final cut points in mSQSq of 0.1, 0.3, and 0.5. They defined 4 ranges in chemical exposure: Minimum (<0.1), Low (0.1– < 0.3), Moderate (0.3– < 0.5), and Maximum (≥0.5). Across these 4 exposure ranges both the incidence and magnitude of toxicity in some laboratory tests increased, the abundance of most stress-sensitive benthic taxa decreased, and the abundance of most stress-tolerant taxa increased. The mSQSq cut point of 0.1 appears to be the target value for protection of benthic resources, the value below which the probability and magnitude of adverse effects either in the laboratory or the field are the lowest. The mSQSq values are rescaled from 0 to 100 to form the SCI, used by the Puget Sound Partnership and environmental managers as a Dashboard Indicator, with biologically relevant targets selected to monitor ecosystem recovery. Integr Environ Assess Manag 2013; 9: 31–49. © 2012 SETAC
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Revision of Sediment quality triad indicators in Puget Sound (Washington, USA): I. a Sediment Chemistry Index and targets for mixtures of toxicants.
Integrated environmental assessment and management, 2012Co-Authors: Edward R. Long, Margaret Dutch, Valerie Partridge, Sandra Weakland, Kathy WelchAbstract:The Washington State Department of Ecology annually conducts Sediment quality monitoring in Puget Sound as a component of the Puget Sound Ecosystem Monitoring Program. Sediment samples are analyzed to determine the concentrations of about 170 chemical and physical variables. A Sediment Chemistry Index (SCI) was derived using the State of Washington Sediment Management Standards to account for the presence and concentrations of mixtures of toxicants. Mean Sediment Quality Standard quotients (mSQSq) were calculated as the basis for the SCI and compared to the incidence and degree of toxicity in laboratory tests and to metrics of the diversity and abundance of resident benthic assemblages in a database consisting of as many as 664 samples. These data were evaluated with co-occurrence analyses to identify “cut points” (i.e., thresholds) in the index below which the frequency and magnitude of biological effects were relatively low and above which they occurred with increasing frequency or magnitude. Iterative trials of different sets of cut points established the final cut points in mSQSq of 0.1, 0.3, and 0.5. They defined 4 ranges in chemical exposure: Minimum (
Edward R. Long - One of the best experts on this subject based on the ideXlab platform.
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revision of Sediment quality triad indicators in puget sound washington usa i a Sediment Chemistry index and targets for mixtures of toxicants
Integrated Environmental Assessment and Management, 2013Co-Authors: Edward R. Long, Margaret Dutch, Valerie Partridge, Sandra Weakland, Kathy WelchAbstract:The Washington State Department of Ecology annually conducts Sediment quality monitoring in Puget Sound as a component of the Puget Sound Ecosystem Monitoring Program. Sediment samples are analyzed to determine the concentrations of about 170 chemical and physical variables. A Sediment Chemistry Index (SCI) was derived using the State of Washington Sediment Management Standards to account for the presence and concentrations of mixtures of toxicants. Mean Sediment Quality Standard quotients (mSQSq) were calculated as the basis for the SCI and compared to the incidence and degree of toxicity in laboratory tests and to metrics of the diversity and abundance of resident benthic assemblages in a database consisting of as many as 664 samples. These data were evaluated with co-occurrence analyses to identify “cut points” (i.e., thresholds) in the index below which the frequency and magnitude of biological effects were relatively low and above which they occurred with increasing frequency or magnitude. Iterative trials of different sets of cut points established the final cut points in mSQSq of 0.1, 0.3, and 0.5. They defined 4 ranges in chemical exposure: Minimum (<0.1), Low (0.1– < 0.3), Moderate (0.3– < 0.5), and Maximum (≥0.5). Across these 4 exposure ranges both the incidence and magnitude of toxicity in some laboratory tests increased, the abundance of most stress-sensitive benthic taxa decreased, and the abundance of most stress-tolerant taxa increased. The mSQSq cut point of 0.1 appears to be the target value for protection of benthic resources, the value below which the probability and magnitude of adverse effects either in the laboratory or the field are the lowest. The mSQSq values are rescaled from 0 to 100 to form the SCI, used by the Puget Sound Partnership and environmental managers as a Dashboard Indicator, with biologically relevant targets selected to monitor ecosystem recovery. Integr Environ Assess Manag 2013; 9: 31–49. © 2012 SETAC
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Revision of Sediment quality triad indicators in Puget Sound (Washington, USA): I. a Sediment Chemistry Index and targets for mixtures of toxicants.
Integrated environmental assessment and management, 2012Co-Authors: Edward R. Long, Margaret Dutch, Valerie Partridge, Sandra Weakland, Kathy WelchAbstract:The Washington State Department of Ecology annually conducts Sediment quality monitoring in Puget Sound as a component of the Puget Sound Ecosystem Monitoring Program. Sediment samples are analyzed to determine the concentrations of about 170 chemical and physical variables. A Sediment Chemistry Index (SCI) was derived using the State of Washington Sediment Management Standards to account for the presence and concentrations of mixtures of toxicants. Mean Sediment Quality Standard quotients (mSQSq) were calculated as the basis for the SCI and compared to the incidence and degree of toxicity in laboratory tests and to metrics of the diversity and abundance of resident benthic assemblages in a database consisting of as many as 664 samples. These data were evaluated with co-occurrence analyses to identify “cut points” (i.e., thresholds) in the index below which the frequency and magnitude of biological effects were relatively low and above which they occurred with increasing frequency or magnitude. Iterative trials of different sets of cut points established the final cut points in mSQSq of 0.1, 0.3, and 0.5. They defined 4 ranges in chemical exposure: Minimum (
Olaf L. F. Weyl - One of the best experts on this subject based on the ideXlab platform.
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Water or Sediment? Partitioning the role of water column and Sediment Chemistry as drivers of macroinvertebrate communities in an austral South African stream.
The Science of the total environment, 2017Co-Authors: Tatenda Dalu, Ryan J. Wasserman, Jonathan D. Tonkin, Tongayi Mwedzi, Mandla L. Magoro, Olaf L. F. WeylAbstract:Water pollution is a critical management issue, with many rivers and streams draining urban areas being polluted by the disposal of untreated solid waste and wastewater discharge, storm water and agricultural runoff. This has implications for biodiversity, and many rivers in the developing world are now considered compromised. We investigated benthic macroinvertebrate community structure and composition in relation to physico-chemical conditions of the water column and Sediments. The study was conducted in an Austral catchment subject to both urban and agricultural pollutants in two different seasons. We assessed whether Sediment characteristics were more important drivers of macroinvertebrate community composition than water column characteristics. We expected clear differences in macroinvertebrate community composition and in the associated community metrics due to distinct flow conditions between the two seasons. A combination of multivariate analyses (canonical correspondence analysis (CCA)) and biological indicator analysis were used to examine these patterns. Chironomidae was the most abundant family (>60%) in the upper mainstem river and stream sites. Stream sites were positively associated with CCA axis 2, being characterised by high turbidity and lower pH, salinity, phosphate concentration, channel width and canopy cover. Canopy cover, channel width, substrate embeddedness, phosphate concentration, pH, salinity and turbidity all had a significant effect on macroinvertebrate community composition. Using CCA variation partitioning, water quality was, however, a better predictor of benthic macroinvertebrate composition than Sediment chemical conditions. Furthermore, our results suggest that seasonality had little effect on structuring benthic macroinvertebrate communities in this south-eastern zone of South Africa, despite clear changes in Sediment Chemistry. This likely reflects the relative lack of major variability in water Chemistry compared to Sediment Chemistry between seasons and the relatively muted variability in precipitation between seasons than the more classic Austral temperate climates.