bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollutant Sources, Depositional Environment, and the Surficial Sediments of Onondaga Lake, New York
Authors: Auer Martin T. , Johnson Ned A. , Penn Michael R. , Effler Steven W. 
Published: July 2010

AbstractA physical and chemical characterization of the surficial sediments of polluted, hypereutrophic Onondaga Lake, New York is presented. Seventy samples were analyzed for a suite of parameters: particle size, moisture content, volatile solids, calcium carbonate, clastics, N, P, chemical oxygen demand, and inorganic and organic C. The lake's sediments are enriched in calcium carbonate (averaging 66% dry weight, DW), at least in part due to an industrial discharge of Ca2+. Enrichment with calcium carbonate serves to dilute other sediment constituents, yielding concentrations of N, P, and organic matter (volatile solids) unusually low for a hypereutrophic system. The distribution of sediment constituents is strongly influenced by lake morphometry: fine sediments (Φ = 4.6) relatively high in N (0.45% DW), P (0.12% DW), and volatile solids (10.7% DW) are characteristic of low energy, deep‐water depositional environments and coarse (Φ = 1.7), calcium carbonate‐rich (83% DW) sediments are typical of shallow, high energy nearshore sites. The location of tributary and point source inputs and the lake's predominant circulation pattern also influence the distribution of clastics, organic matter, and P. Cluster analysis was used to identify regions of common sediment character: (1) nearshore sediments rich in calcium carbonate, (2) shallow water sediments directly influenced by tributary and point source discharges, and (3) deep‐water sediments rich in N, P, and organic matter. The deep‐water sediment type was further subdivided in recognition of the high chemical oxygen demand characteristic of the deepest portions of the depositional basin.
Reversing Acidification in a Forested Catchment in Southwestern Sweden: Effects on Soil Solution Chemistry
Authors: Giesler Reiner , Moldan Filip , Lundström Ulla , Hultberg Hans 
Published: July 2010

AbstractThe exclusion of acid precipitation in whole‐catchment experiments can provide valuable information to further our understanding of recovery processes of acidified soils. In this study, we focused on the reversibility of acidification‐induced changes in different soil horizons when anthropogenic deposition was excluded. A small forested catchment in the Gårdsjön area in southwest Sweden was covered with a transparent roof in April 1991 and sprinkled with water that simulated preindustrial deposition levels. Within the roofed catchment and a reference catchment the soil solution was studied using a centrifugation drainage technique. Sulfate concentrations in the O and E horizons decreased by 75 and 65%, respectively, within 3 mo after treatment. In the Bs horizon, the sulfate concentration decreased more gradually, reaching about 52% of the pretreatment level in 1993 after 2.5 yr of treatment. The decline in sulfate concentrations in the runoff followed the pattern observed in the Bs horizon. The net loss from the catchment during the first 2.5 yr of the treatment period represents approximately 9% of the phosphate‐extractable sulfate pool. No increase in soil solution pH occurred until 1994. In 1993, Al concentrations were lower compared with those found in earlier samplings of the soil solution and runoff. Fluctuations in Al concentrations were correlated most strongly with changes in ionic strength in the soil solution and runoff. Nitrate concentrations remained unchanged in the soil solution and runoff. Concentrations of NO−3 were, however, already low (<30 µmol L−1) before the exclusion.
Calibration and Testing of Simulation Models for Evaluation of Trench Cap Designs
Authors: Paige G. B. , Stone J. J. , Lane L. J. , Hakonson T. E. 
Published: July 2010

AbstractA prototype decision support system (PDSS) using multi‐objective decision theory and embedded simulation models is being developed to evaluate landfill cover designs for low‐level radioactive waste disposal sites. To evaluate the performance of the PDSS, the simulation models, which are used to parameterize the decision model when data are not available, must be calibrated and tested. The two linked simulation models embedded in the PDSS are the HELP (hydrologic evaluation of landfill performance) and CREAMS (chemicals, runoff, and erosion from agricultural management systems) models. Data from a field demonstration study at Hill Air Force Base were used to calibrate the simulation models. The models were calibrated using water balance and erosion parameters for two alternative designs, a control soil cover and a modified USEPA Resource Conservation and Recovery Act design. Simulations were run using the calibrated model parameters for a 200‐yr period to evaluate the long‐term performance of the models. The progressive annual average for all of the output parameters was within the 95% confidence limits of the long‐term mean by Year 60 for both of the cover designs evaluated. The results of the calibration and long‐term evaluation of the simulation models were reasonable for the length of the data set. To fully validate and test the simulation models, other data sets of landfill covers in a variety of climates are needed.
Effects of Olestra in Sewage Sludge on Soil Physical Properties
Authors: Logan T. J. , Harrison B. J. , McAvoy D. C. , Greff J. A. 
Published: July 2010

AbstractThis study investigated the potential effects of olestra, a fat replacer, on soil physical properties following amendment in sewage sludge. Liquid and solid forms of olestra, ranging the product formulation properties, were added to anaerobically digested sludge at concentrations of 5.7 and 4.4% by weight, respectively. Sludges, with and without the two olestra formulations, were dewatered to 45% solids by weight and uniformly mixed with four distinctly different soils: Miamian silt loam (fine, mixed, mesic, Typic Hapludalf), Kokomo silt loam (fine, mixed, mesic, Typic Argiaquoll), Hazleton sand (loamy‐skeletal, mixed, mesic, Typic Dystrochrept), and Paulding clay (very fine, illitic, nonacid, mesic, Typic Haplaquept) at a rate of 25% by weight of sludge to soil. The mixtures were incubated in a greenhouse and samples were taken at 1, 6, 12, and 20 wk and analyzed for: bulk and particle densities; water retention at 0, −5.9, −33, and −1500 kPa matric potentials; saturated hydraulic conductivity (Ks); water‐stable aggregates; shrinkage; Atterberg limits; and pocket penetrometer resistance. Results showed that the presence of olestra in sewage sludge at concentrations as high as 6% by weight should not exhibit any long‐term effects on these soil physical properties.
Threshold Application Rates of Wood Ash to an Acidic Forest Soil
Authors: Kahl Jeffrey S. , Fernandez Ivan J. , Rustad Lindsey E. , Peckenham John 
Published: July 2010

AbstractChanges in soil and soil solution chemistry were studied for 2 yr after application of wood ash to an acidic forest Spodosol. Application rates to four 50 m2 plots were: 0 (control), 6, 13, and 20 Mg CaCO3 equivalents per hectare (Mg ha−1). In soil solution, the 13 and 20 Mg ha−1 treatments caused large but generally transient increases in base cations, pH, and anions. At 20 Mg ha−1, solution concentrations of H, acid neutralizing capacity (ANC), K, and SO4 remained elevated for 20 mo. There was minimal response in soil solutions at 6 Mg ha−1, suggesting that this rate may represent a threshold below which there is only minor response in soil solution chemistry. Loss of soil N into soil solution (as NO3) at the two higher application rates may have decreased available‐N in the already N‐limited soil. In the O horizon, all treatments resulted in increased pH and higher exchangeable Ca, K, Mg, CEC, and percent base saturation; Mn and Al decreased. In the B horizon, exchangeable Ca, K, Mg, and percent base saturation were higher than in the control. Responses in soil chemistry were not generally proportional to the ash application rate. Furthermore, the responses in soil chemistry at different application rates were generally not distinguishable from each other after 25 mo. The treatment rate of 6 Mg ha−1 ash was sufficient to favorably alter soil exchange chemistry, without seriously affecting solution chemistry. Above 6 Mg ha−1, soil exchange sites were unable to buffer ash amendments, resulting in substantial changes in solution chemistry.
Heavy Metal Effects on the Metabolic Activity of Elliptio complanata: A Calorimetric Method
Authors: Cheney Marcos A. , Criddle Richard S. 
Published: July 2010

AbstractThe effects of short time exposure to mercury (Hg2+), cadmium (Cd2+), and copper (Cu2+) ions on the metabolic activity of gill tissue from the freshwater bivalve Elliptio complanata were investigated by isothermal calorimetry and respirometry. Metabolic heat rates were altered following exposure of gill tissue to these ions over the concentration range from 10−6 to 10−3 M. The effects of metal ions on metabolic heat rates were metal ion specific and time and concentration dependent. Treatment of tissue with low concentrations of Hg2+ and Cu2+ for short times caused stimulation of metabolic heat rates. Longer exposures and higher concentrations caused inhibition. Cadmium was inhibitory under all conditions tested. Treatment of mitochondria isolated from gill and muscle tissues showed a similar pattern of stimulation of respiratory rate at low concentration and inhibition at higher concentration. Analysis of CO2, and O2 from the headspace gasses in the calorimeter ampule showed an enhancement of respiratory quotient (RQ, i.e., RCO2/RO2 where R = rate) following addition of 10−3 M Cd2+ for 30 min. The microcalorimetric method proved to be a useful technique to assess toxicity of heavy metals on the gills of a freshwater bivalve.
A Passive Flux Sampler for Measuring Ammonia Volatilization from Manure Storage Facilities
Authors: Sommer Sven G. , Sibbesen Erik , Nielsen Tina , Schjørring Jan K. , Olesen J. E. 
Published: July 2010

AbstractAn integrated horizontal flux technique was tested for quantification of ammonia (NH3) emission from manure storage. The method is based on a simple and inexpensive passive flux sampler consisting of two disconnectable glass tubes, coated on the inside with oxalic acid. The flux sampler is mounted at a minimum of three heights, 20 to 100 cm above the storage, on each of four masts, placed perpendicular to each other around the storage. The samplers continuously integrate the horizontal flux of NH3 at the various heights. After analysis of the NH3 content in the tubes facing the storage (exposed tubes) and surroundings (background tubes), the vertical flux of NH3 from the storage can be obtained by application of mass balance equations (micrometeorological mass balance technique). For the measurements of NH3 volatilization from slurry tanks or lagoons the technique is useful, because it is not affected by heterogenity in wind profiles and the masts with the passive flux samplers are placed on the periphery of the slurry store. The flux samplers were able to accurately quantify NH3 volatilization from slurry tanks. From above the rim of the slurry tank the horizontal net flux decline exponential with height. This may facilitate the calculation of the vertical flux of NH3. Bypass of NH3 between exposed and background tubes may occur during periods with high wind velocities (>10 m s−1) or when more than one‐fifth of the oxalate in the exposed tube has reacted. However, if bypass occurs, a good estimate of NH3 volatilization can still be obtained by addition of exposed and background tubes, because the NH3 flux from storage are usually much greater than the flux from surroundings. Bypass due to high net horizontal fluxes of NH3 can be avoided by reducing the measuring period or increasing the length of the tubes. Storm conditions with heavy rain can flood the flux samplers and spoil the measurements. Within the study NH3 volatilization from stored cattle slurry were measured eight times from October to December 1992. Daily loss rates of NH3 varied between 0.33 and 4.15 g NH3‐N m−2 d−1.
Herbicide and Nitrate Distribution in Central Iowa Rainfall
Authors: Hatfield J. L. , Wesley C. K. , Prueger J. H. , Pfeiffer R. L. 
Published: July 2010

AbstractHerbicides are detected in rainfall; however, these are a small fraction of the total applied. This study was designed to evaluate monthly and annual variation in atrazine (6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine), alachlor (2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide), metolachlor (2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)acetamide), and NO3‐N concentrations in rainfall over Walnut Creek watershed south of Ames, IA. The study began in 1991 and continued through 1994. Within the watershed, two wet/dry precipitation samplers were positioned 4 km apart. Detections varied during the year with >90% of the herbicide detections occurring in April through early July. Concentrations varied among events from nondetectable amounts to concentrations of 154 μg L−1, which occurred when atrazine was applied during an extremely humid day immediately followed by rainfall of <10 mm that washed spray drift from the atmosphere. This was a local scale phenomenon, because the other collector had a more typical concentration of 1.7 μg L−1 with an 8‐mm rainfall. Variation between the two collectors suggests that local scale meteorological processes affect herbicide movement. Yearly atrazine deposition totals were >100 μg m−2 representing <0.1% of the amount applied. Nitrate‐N concentrations in precipitation were uniformly distributed throughout the year and without annual variation in the concentrations. Deposition rates of NO3‐N were about 1.2 g m−2. Annual loading onto the watershed was about 25% of the amount applied from all forms of N fertilizers. Movement and rates of deposition provide an understanding of the processes and magnitude of the impact of agriculture on the environment.
Response of White Clover to Ozone in Different Environments
Authors: Heagle Allen S. , Reinert Richard A. , Miller Joseph E. 
Published: July 2010

AbstractThe value of research on effects of O3 done in greenhouse or field exposure systems is often questioned because chamber environments may affect plant response. Foliar injury, chlorophyll, and forage weight responses of two clones of white clover (Trifolium repens L.) to ambient O3 were compared for plants grown in charcoal‐filtered (CF) and nonfiltered air (NF) in greenhouse and open‐top field chambers and in ambient air (AA) plots at Raleigh, NC. One clone is sensitive to O3 (NC‐S), whereas the other is resistant (NC‐R). Comparisons of individual clone responses in CF vs. NF treatments in the greenhouse and in the field and the proportional response of the clones (defined as the NC‐S/NC‐R response ratio) were used to indicate the relative response to O3 in the different environments. Foliar injury and chlorophyll responses of NC‐S to O3 were similar in the NF greenhouse, NF open‐top chambers, and in AA. However, for individual harvests, the percentage decrease in NC‐S forage weight in NF compared with CF was 7 to 23% greater in the greenhouse than in open‐top chambers. The NC‐S/NC‐R forage ratios indicated that clover response to O3 in NF open‐top field chambers was the same as in AA. Large environmental differences between greenhouse and open‐top chambers apparently caused differences in plant responses to O3, whereas relatively small environmental differences between open‐top chambers and ambient air did not.
Estimating the Effects of Changing Land Use Patterns on Connecticut Lakes
Authors: Field Cathryn K. , Siver Peter A. , Lott Anne‐Marie 
Published: July 2010

AbstractChanges in land use of 30 Connecticut lake watersheds between 1934, 1970, and 1990 were quantified using aerial photographs. Results were used with existing land use models to estimate changes in concentrations of total phosphorus (TP) and total nitrogen (TN) over the 56‐yr period. On average, the watersheds have increased in urban‐residential land cover from 2% in 1934 to 16% in 1990, and decreased in agricultural land from 20 to 7% during the same time period. The mean percentage of forested land has remained relatively constant. Based on the land use models of Norvell et al. (1979) and Frink (1991), the mean estimated total phosphorus concentration (eTP) increased from 15 μg L−1 in 1934 to 25 μg L−1 in 1990. The eTP concentrations increased in 26 of the 30 study lakes. In contrast, the mean estimated concentration of total nitrogen (eTN) increased only 20% from 374 to 450 μg L−1. Principal component analysis (PCA) was used to score each study lake according to its current trophic and ionic condition using chemical data from 1991 to 1993, and the results regressed against the 1990 land use types. Trophic scores were most highly correlated with forest cover, while ionic scores were most highly correlated with forest cover and the degree of urban‐residential land cover. The effect of water retention time is discussed. Land use models provide useful tools in the management of lakes.
Groundwater Vulnerability to Pesticide Contamination on a Regional Scale
Authors: Soutter Marc , Pannatier Yvan 
Published: July 2010

AbstractRegional groundwater vulnerability maps that indicate the impact of leaching uncertainties, should be accompanied by maps expressing the probability of surpassing that index value. This case study presents first steps in a methodology for developing such an index and the probability of its value. Regionalization of piezometric data provided an estimate of the lacking water table depth at soil profiles. Monte‐Carlo simulations of pesticide fate on these soil profiles produced local distributions of a groundwater vulnerability index. Soil hydraulic properties were randomly generated using pedotransfer functions and experimental probability density functions of particle‐ size distribution and organic matter content. Medians of locally simulated distributions were then mapped to show the spatial distribution of groundwater vulnerability. It appeared that the resulting groundwater vulnerability map might be significantly affected by soil spatial variability, although soils are quite similar throughout the area. Deciles of the locally simulated distributions seem to show intrinsic coregionalization. This property could be used to build, over the whole area, an estimated groundwater vulnerability index distribution.
Input Parameter and Model Resolution Effects on Predictions of Solute Transport
Authors: Inskeep W. P. , Wraith J. M. , Wilson J. P. , Snyder R. D. , Macur R. E. , Gaber H. M. 
Published: July 2010

AbstractModel predictions of solute transport using larger scale soil and climatic data sets may be useful for classifying mapping units based on their susceptibility to chemical leaching. However, model predictions based on input data sets with low spatial resolution may not accurately reflect transport processes occurring in situ. The goal of the current study was to compare several modeling approaches that might be applicable for classifying soil mapping units (1:24 000) according to their leaching potential to (i) model results based on detailed site‐specific measurements and (ii) observed data collected at a field site (Borollic Calciorthid) in southwestern Montana. Data from a 2‐yr field study of pentafluorobenzoic acid (PFBA), 2,6‐difluorobenzoic acid (DFBA) and dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) transport in fallow and cropped systems under two water application levels were compared to simulations obtained using the Chemical Movement in Layered Soils (CMLS) and Leaching and Chemistry Estimation (LEACHM) models. The resolution of model input parameters was varied based on sources of data. In Case 1, model inputs were obtained primarily from detailed soil profile characterization and site‐specific measurements of precipitation, irrigation, and pan evaporation. LEACHM predictions were also generated using estimated conductivity and retentivity functions from textural data obtained from the USDA‐NRCS Soil Survey (SSURGO) database (Cases 2 and 3). CMLS predictions were generated using (i) detailed site‐specific measurements (Case 1) and (ii) estimated volumetric water contents from textural data (SSURGO) and estimated daily precipitation and evapotranspiration (ET) from the Weather Generator (WGEN) and Montana Agricultural Potentials (MAPS) climate database (Cases 2 and 3). Comparison of observed and simulated mean solute travel times showed that (i) LEACHM and CMLS performed adequately with high‐resolution model inputs, (ii) model performance declined when field conditions were conducive to preferential flow, (iii) estimated Ks values from regression equations based on textural data were problematic for generating adequate predictions using LEACHM, and (iv) CMLS predictions were less sensitive to data input resolution, due in part to the fact that CMLS provides an oversimplified description of transport processes.
Incorporating Spatial Variability into GIS to Estimate Nitrate Leaching at the Aquifer Scale
Authors: Görres Josef , Gold Arthur J. 
Published: July 2010

AbstractWe evaluated the effect of spatial variability of selected intrinsic soil properties and extrinsic management practices on the groundwater quality in the 330‐ha recharge area of a high yield well site in Rhode Island. The analyses were performed at different support scales, ranging from point level to a support level equal to the entire recharge area. We used a mass balance model that relates leaching from the vadose zone to long‐term estimates of NO3‐N concentration at the well. We used a GIS database and stratified sampling for both soil characterization and assessment of spatial variability of NO3 leaching. The LEACHA/N rootzone model was used in conjunction with Monte Carlo simulation to generate cumulative distribution functions (CDFs) for leaching from different land strata (given by combinations of soil type and land use). To simulate the spatial variability of properties that served as inputs to the root zone model, we used CDFs of spatial distributions of soil properties and CDFs of the spatial variability of fertilizer application rates within a field. These strata scale CDFs were then combined to generate CDFs of the NO3‐N concentrations at the well, i.e., at a recharge area support scale. Although considerable variability was found at a point support scale, the analyses generated a markedly lower variability at the recharge area support scale. The results suggest that GIS data bases generated at scales available to resource managers (i.e., 1:12 000 and 1:24 000) may be well suited to manage the water quality of large production scale wells.