bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vegetative Filter Treatment of Dairy Milkhouse Wastewater
Authors: Schwer C. B. , Clausen J. C. 
Published: July 2010

AbstractA vegetated filter strip constructed to treat milkhouse wastewater from a Vermont dairy farm was evaluated to determine its effectiveness in reducing solids, P and N concentrations and exports in surface and subsurface flow. The liquid waste was applied twice daily via a level lip spreader at a rate of 2.94 cm/wk on a vegetated loam soil having a 2% slope. The flow and concentrations of inputs and surface and subsurface outputs were continuously monitored during the 2‐yr study. The strip significantly (P < 0.01) reduced solids, P, and N on a concentration basis, and retained 95% solids, 89% P, and 92% N on a mass basis. Retention was the greatest during the growing season and the poorest during snowmelt periods. Concentrations in subsurface outputs were greater than in surface runoff and over 75% of the mass export was in subsurface flow. Comparisons of this study with values reported in the literature suggests that hydraulic loading rate governs the effectiveness of filter strip treatment.
Infiltration of Wastewater in a Newly Started Pilot Sand‐Filter System: II. Development and Distribution of the Bacterial Populations
Authors: Pell Mikael , Nyberg Fred 
Published: July 2010

AbstractThe objective of the study was to monitor the development of the bacterial populations in a sand‐filter system consisting of a three‐chambered septic tank, a sand filter with a one‐person capacity, and eight columns. The system was loaded with 67 L m−2 day−1 of an artificial wastewater. Monitoring was conducted from start‐up until a steady state was reached. The wastewater contained over two orders of magnitude higher numbers of aerobic bacteria in the third chamber compared to the first chamber of the septic tank. Populations of aerobic and denitrifying bacteria in the sand surface layer of the columns increased markedly in number within the first 10 d, reaching peaks on Day 24. The following decline was attributed to the development of anaerobic conditions. This hypothesis was supported by an observed increase in the number of sulfate‐reducing bacteria. No increase in nitrifier populations was observed. In the sand‐filter surface layer both aerobic and denitrifying bacteria increased in numbers until Days 65 to 75, thereafter remaining in a steady state at around 108 bacteria g−1 dry sand. Populations of ammonium‐ and nitrite‐oxidizing bacteria both started out at low levels. Thereafter they increased until Days 70 to 95, by which time populations of 106 to 107 and 105 to 106 g−1 dry sand, respectively, had been established. By the time that bacterial growth had reached a steady state, an estimated 8% of the pore volume in the sand surface layer was occupied by bacterial cells. This biomass accounts for the amounts of N and P in the sewage water produced by one person during a 20‐d period.
Dissolved Organic Matter Interaction with Napropamide and Four Other Nonionic Pesticides
Authors: Lee Dar‐Yuan , Farmer Walter J. 
Published: July 2010

AbstractEquilibrium dialysis was used to measure the extent of interaction between dissolved organic matter (DOM) and five nonionic pesticides. The association‐dissociation of DOM with the relatively polar, nonionic pesticide napropamide [2‐(a‐naphthoxy)‐N,N‐diethylpropionamide], was emphasized in this study. A negative linear correlation was found between the log of the solubility and the log of the association coefficient of these five pesticides with dissolved humic acid derived from peat (peat‐DHA). However, napropamide, which is more water soluble and therefore considered less hydrophobic than lindane (γ‐1,2,3,4,5,6‐hexachlorocyclohexane) and prometryn [2,4‐bis(isopropylamino‐6‐methyl‐thio‐s‐triazine] had a greater extent of association with peat‐DHA, suggesting that hydrophobicity of nonionic pesticides is not the only factor governing their interaction with DOM. When comparing DOM from several sources, dissolved humic acid had a higher affinity than dissolved fulvic acid for napropamide, DDT [1,1,1‐trichloro‐2,2‐bis(p‐chlorophenyl)ethane], and lindane. Association of napropamide with peat‐DHA increased with increasing pH above pH 6.4, decreasing ionic strength, and decreasing charge on cations added to the system. Dissociation studies showed that the interaction between napropamide and peat‐DHA was not fully reversible. The results suggest that the source of the DOM, properties of the solution environment, and reversibility of the interaction should be taken into account when evaluating the interaction between DOM and nonionic pesticides. In addition, dissolved humic and fulvic acid released from two soils showed a different affinity for napropamide compared to bulk soil organic matter when the ability of the whole soil to retain napropamide was expressed on the fraction organic‐carbon‐content basis.
The Degradation of Trichloroethylene in Mixed Methanogenic Cultures
Authors: Baek Nam H. , Jaffe Peter R. 
Published: July 2010

AbstractSymbiosis between nonmethanogenic fermenters and methanogens, which occurs through a phenomenon called the interspecies hydrogen transfer, can play an important role in the growth of these microorganisms. In the degradation of natural materials, methane production is frequently supported by this interspecies hydrogen transfer from fermenters that degrade the primary substrate, to methanogens that use the hydrogen to reduce carbonate to methane. The objective of this work was to evaluate the role of the fermenters in the degradation of trichloroethylene during methanogenesis. The results show that the fermentation process enhances the anaerobic degradation of trichloroethylene. In addition, it is shown that chloroethane appears as one of the products of the degradation of trichloroethylene by this mixed culture. The production of chloroethane indicates that hydrogenation of the double bond of a chlorinated ethene occurs during the degradation of trichloroethylene by cultures containing nonmethanogenic fermenters and methanogens. The metabolism involved in this degradation process may therefore provide a possible mechanism to completely degrade trichloroethylene under anaerobic conditions, because it is known that chloroethane is degraded rapidly to inorganic carbon.
Acidity Produced by Leguminous Plants through Symbiotic Dinitrogen Fixation
Authors: Liu Wen‐Cheh , Lund L. J. , Page A. L. 
Published: July 2010

AbstractRed clover (Trifolium prateuse L.), sweet clover (Meliotus alba Medik.), alfalfa (Medicago sativa L.), and crown vetch (Vica villosa Roth) were grown in nitrogen‐free Hoagland's solution in a declining nutrient condition. Increases in acidity of the nutrient solutions were recorded over the experimental period. In general, the excess bases and the excess bases/nitrogen ratio varied considerably among harvests. Significant positive relationships between total N and proton efflux, excess bases and H+ excretion, and dry weight and H+ efflux were observed. The milligrams H+ produced per gram N fixed for the four legumes were 49 for red clover, 43 for crown vetch, 42 for alfalfa, and 37 for sweet clover. By extrapolating the protons produced per gram dry weight in this study to yields commonly observed in the field, annual hydrogen production per hectare would amount to 9.7 kg for red clover, 4.6 kg for sweet dover, 15.2 kg for alfalfa, and 4.5 kg for crown vetch. The amounts of acidity produced per hectare per year calculated from the values of N2 fixation were 5.2 to 14 kg by alfalfa, 4.2 to 9.4 kg by red clover, 3.2 to 7.1 kg by sweet clover, and 3.9 to 6.8 kg by crown vetch. The study demonstrates that production of H+ through symbiotic fixation by legumes is an important source of acidity in agricultural ecosystems. The acidifying effect of legumes could, in the long‐term, result in acidification of the bulk soil causing the downward leaching of exchangeable cations and a decrease in base saturation.
Tolerance of Red Oak and American and European Beech Seedlings to Aluminum
Authors: Thornton F. C. , Schaedle M. , Raynal D. J. 
Published: July 2010

AbstractThe effect of aluminum (Al) on the growth of red oak (Quercus rubra L.), American beech (Fagus grandifolia Ehrh.), and European beech (Fagus sylvatica L.) seedlings was studied in solution culture containing from 0 to 3000 µM Al at pH 4.0. Aluminum had no detrimental effect on biomass of shoots of red oak and American beech. Shoot biomass of European beech was significantly reduced by Al, with greater reductions measured for seedlings grown in lower ionic‐strength media. Root biomass of species did not decline with increasing Al, and actually increased in some Al treatments. Generally, Ca, Mg, and P tissue concentrations of leaves and roots decreased with increasing solution Al for all three species. Even at the lowest solution Al concentration, 500 µM, significant reductions relative to the controls were measured. Of the elements measured, P appeared to be the most strongly correlated with shoot biomass response, having r values of 0.87 and 0.98 for American beech and European beech, respectively. Results from these studies indicate that the risk of direct effects of toxic soil solution Al concentrations on growth of red oak and American beech seedlings is low. However, soil solution concentrations of 500 µM have been reported in Europe and these correspond to the Al level found to significantly reduce shoot biomass of European beech in this study.
Uranium, Vanadium, and Molybdenum in Saline Waters of California
Authors: Bradford G. R. , Bakhtar D. , Westcot D. 
Published: July 2010

AbstractAnalyses of saline water samples from large salt water bodies, agricultural drainage and evaporation ponds, and soil water extracts were used to determine the extent of elevated uranium (U), vanadium (V), and molybdenum (Mo) in agricultural environments of the San Joaquin Valley. Saline water samples and soil extracts were pretreated by chelation and solvent extraction to separate and concentrate, U, V, and Mo for analyses. Mean concentrations of U, V, and Mo were considerably elevated in agricultural drainage and evaporation ponds of the San Joaquin Valley compared to saline waters of Salton Sea and Mono Lake. Relatively high correlation coefficients were observed between U, Mo, and salinity.
Sensitivity of Tree Seedlings to Aluminum: II. Red Oak, Sugar Maple, and European Beech
Authors: Kelly J.M. , Schaedle M. , Thornton F. C. , Joslin J. D. 
Published: July 2010

AbstractA series of solution culture and greenhouse studies were conducted as part of the ALBIOS project to evaluate the response of northern red oak (Quercus rubra L.), sugar maple (Acer saccharum Marsh.), and European beech (Fagus sylvatica L.) seedlings to Al. Several soil and plant variables were evaluated as possible indicators of plant response to increased Al. Of the soil variables evaluated, 0.01 M SrCl2 extractable Al was found to be well correlated (r = 0.70) with plant response. Changes in root branching frequency were found to be an even more sensitive indicator of potential impact, although routine applications in the field was deemed impractical. Of the three species evaluated, northern red oak was the most sensitive to increasing Al, exhibiting root growth reductions at Al concentrations ranging from 0.12 to 0.28 mM in two separate experiments. The Ca/Al ratio was found to be particularly important in establishing toxicity thresholds for northern red oak with no Al impacts observed when Ca/Al ratio was greater than 4. In low ionic strength solution culture experiments, shoot growth of European beech was reduced by 40% at an Al concentration of 0.5 mM. Foliage tissue Al concentrations tended to be less reliable than root concentrations as predictors of plant response. Comparison of established critical tissue levels (CTL) of Al to tissue data from various field sites indicated that only northern red oak (CTL = ∼6600 µg g−1) may be near impact levels, whereas soil and soil solution data indicate rhizosphere levels generally well below those producing an impact. All results and thresholds must be extrapolated with caution because there are many interacting factors producing a variety of responses in the face of seemingly similar experimental treatments.
Sensitivity of Tree Seedlings to Aluminum: III. Red Spruce and Loblolly Pine
Authors: Raynal D. J. , Joslin J. D. , Thornton F. C. , Schaedle M. , Henderson G. S. 
Published: July 2010

AbstractUnexplained declines in the growth of both red spruce (Picea rubens Sarg.) and loblolly pine (Pinus taeda L.) have been reported within their natural ranges recently. The possible role of Al phytotoxicity as a causal agent in these declines has been studied extensively. Results of experiments with seedlings grown in solution, sand, and soil indicate minimal involvement of Al in the decline of loblolly pine. However, both controlled studies and field data indicate that reductions in tissue Ca and Mg may occur at Al concentrations well below those causing direct injury. Thus, Al may be involved in reductions in pine growth through interference with nutrient uptake and translocation. Several independent studies demonstrate that Al does directly affect growth of red spruce seedlings at Al concentrations of ≤0.25 mM, a concentration that might approach the range of soil solution Al concentrations measured in native red spruce stands in the Appalachian Mountains (0.1–0.28 mM). In these seedling studies, concentration of Ca and Mg in red spruce roots and foliage were also markedly reduced by relatively low solution Al concentrations. Thus, a contributing role for Al phytotoxicity in red spruce decline, through both direct biomass reduction and indirect effects due to interference with nutrient uptake, appears plausible.
Geochemical Factors Controlling the Mobilization of Inorganic Constituents from Fossil Fuel Combustion Residues: II. Review of the Minor Elements
Authors: Eary L. E. , Rai Dhanpat , Mattigod S. V. , Ainsworth C. C. 
Published: July 2010

AbstractPast studies of the environmental aspects of fossil fuel waste disposal have focused on determining elemental concentrations, elemental distributions, and empirical rates of elemental extraction. The concentration data for the minor elements (i.e., As, B, Ba, Cd, Cr, Cu, Pb, Mn, Hg, Mo, Ni, Se, Sr, V, and Zn) are extremely variable and are dependent on fuel composition and combustion processes. Studies of elemental extraction rates have provided empirical information on short‐term leaching behavior that is relevant only to a specific waste sample. Extraction studies serve to characterize the initial states of wastes prior to disposal but generally have not provided information on the dominant weathering reactions that will control the long‐term concentrations of minor elements in the disposal environment. We propose that a more useful approach for understanding leachate chemistry involves the consideration of the thermodynamics of specific dissolution/precipitation, adsorption/desorption, and redox speciation reactions that occur during weathering in addition to empirical data. Because fossil fuel wastes are composed of high‐temperature solids that formed under conditions of combustion, this approach can be used to describe the reaction paths governing the alteration of the high‐temperature solids to assemblages of secondary solids and aqueous species that are stable in weathering environments. The depiction of leaching behavior through solubility and speciation relationships rather than through empirical interpretations of extraction rates allows one to establish bounds for the aqueous concentrations of various elements, given information on the chemistry of waste solids and on physical and chemical conditions. The determination of thermodynamic data and application of those data to understanding the leachate chemistry of the minor elements in the disposal environment remains an area where much research is needed.
Application of Radioactive Fallout Cesium‐137 for Measuring Soil Erosion and Sediment Accumulation Rates and Patterns: A Review
Authors: Ritchie Jerry C. , McHenry J. Roger 
Published: July 2010

AbstractRadioactive fallout 137Cs (cesium‐137) deposited across the landscape from atmospheric nuclear tests is strongly absorbed on soil particles limiting its movement by chemical and biological processes. Most 137Cs movement in the environment is by physical processes; therefore, 137Cs is a unique tracer for studying erosion and sedimentation. Cesium‐137 loss from a watershed has been shown to correlate strongly with soil loss calculated by the Universal Soil Loss Equation (USLE) or measured from small runoff plates. By measuring spatial patterns of 137Cs in vertical and horizontal planes across the landscape, rates of soil loss or deposition can be measured for different parts of a watershed. Even within landscape units, redistribution of soil can be mapped and erosion or deposition rates for different parts of individual fields measured and mapped. Sediment accumulation rates can be measured by comparing the vertical distribution of 137Cs in sediments with the temporal deposition of fallout 137Cs from the atmosphere to locate sediment horizons. Using these dated sediment horizons, sediment accumulation rates can be measured. Interpretations about the location of these dated horizons must consider particle size of the sediments, reworking of deposited sediments, diffusional movement of 137Cs, and time rates of physical process in the sedimentation process. The 137Cs technique can be used to determine sediment accumulation rates in a wide variety of depositional environments including reservoirs, lakes, wetlands, coastal areas, and floodplains. The bibliography shows that 137Cs has been used widely for studying erosion and sedimentation in many different environments around the world.
Soil Nitrate Accumulations following Nitrogen‐Fertilized Corn in Pennsylvania
Authors: Roth G. W. , Fox R. H. 
Published: July 2010

AbstractNitrate (NO−3‐N) contamination of surface waters and groundwater in Pennsylvania has made it necessary to evaluate the impact of N fertilization practices for corn (Zea mays L.) on the accumulation of NO−3‐N in the soil. This study was initiated to (i) determine soil NO−3‐N accumulations following the harvest of corn fertilized at various N rates in Pennsylvania, (ii) estimate the soil nitrate accumulation at the economic optimum N rate under a range of conditions, and (iii) estimate changes in soil NO−3‐N over the winter. Soils in nine N response experiments in central and southeastern Pennsylvania and in a long‐term N source experiment in central Pennsylvania were sampled in 30.5‐cm increments to 122 cm following corn harvest in the fall of either 1986 or 1987. Five of these experiments were sampled again the following spring. All experiments were located on limestone‐derived silt loams classified as either Duffield (fine‐loamy, mixed, mesic Ultic Hapludalfs), Hagerstown (fine, mixed, mesic Typic Hapludalfs), or Murrill (fine‐loamy, mixed, mesic Typic Hapludults) soils. Soil NO−3‐N accumulation to 120 cm in the N response experiments, averaged over N rates, ranged from 36 to 295 kg NO−3‐N ha−1. Sites with a history of manure applications generally had greater NO−3‐N accumulation. At economic optimum N (EON) fertilizer rates, estimates of soil NO−3‐N accumulation to 120 cm ranged from 41 to 138 kg N ha−1. Accumulations at the EON averaged 74 kg ha−1 in nonmanured sites and 94 kg ha−1 in responsive, manured sites. Soil NO−3‐N accumulation in two check treatments on manured sites where no yield response to N occurred averaged 169 kg NO−3‐N ha−1. In the longterm experiment, soil NO−3‐N accumulation at the economic optimum N rate in the manured system was greater (135 kg N ha−1) than in the nonmanured system (115 kg N ha−1). Changes in soil NO−3‐N accumulations between fall and spring were variable, but often a substantial accumulation was still present in the spring. The results of this study indicate need for careful N management in manure‐based systems, identification of nonresponsive and potentially polluting sites, and consideration of soil NO−3‐N accumulation in N fertilizer recommendations.
Exchange of Phosphorus from Shallow Sediments at Nine Alberta Lakes
Authors: Shaw J. F. H. , Prepas E. E. 
Published: July 2010

AbstractPotential exchange of P between sediments and lakewater and particulate sediments and porewater was evaluated in nine eutrophic lakes in Alberta. Lakewater above the sediments, porewater, and sediments were collected from shallow depths during May to August 1986. Lakewater soluble‐reactive P concentrations ([SRP]) were positively correlated with porewater [SRP] (P < 0.01) and negatively with the Fe/P molar ratio in porewater (P < 0.001). Potential release of SRP from sediments to lakewater (by molecular diffusion) was positively correlated with particulate P fractions that are known to exchange P with water (P < 0.01). In porewater, [SRP] was positively correlated with Fe2+ concentration and weakly correlated with pH (P < 0.001 and 0.05, respectively). These results indicate (i) potential transport of P from sediments to lakewater when Fe is not abundant, (ii) common sources and similar mobilities of Fe and P, and (iii) importance of pH in regulation of P exchange between particulate sediments and porewater. No significant relationships (P > 0.05) were found between porewater [SRP] and particulate P fractions. In this study, correlation coefficients were generally low, which suggests (i) the chemical fractionation of particulate sediments failed to isolate the exchangeable P fraction and (ii) partitioning of P within sediments and the release of P from sediments to lakewater are complex processes, only partially regulated by pH and Fe2+ in porewater. To gain better understanding of P release from shallow sediments, future studies should include possible interactions between P and redox potential, Al, Mn, Ca, and S.
A Water Balance Study of Two Landfill Cover Designs for Semiarid Regions
Authors: Nyhan J. W. , Hakonson T. E. , Drennon B. J. 
Published: July 2010

AbstractThe results from several field experiments on methods to control soil erosion, biointrusion, and water infiltration were used to design and test an enhanced landfill cover that improves the ability of the disposal site to isolate buried wastes. The performance of the improved cover design in managing water and biota at the disposal site was compared for 3 yr with that obtained from a more conventional design that has been widely used in the industry. The conventional cover design consisted of 20 cm of sandy loam topsoil over 108 cm of a sandy silt backfill, whereas the improved design consists of 71 cm of topsoil over a minimum of 46 cm of gravel, 91 cm of river cobble, and 38 cm of sandy silt backfill. Each plot was lined with an impermeable liner to allow for mass balance calculation of water dynamics. Results over a 3‐yr period, including 2 wet yr, demonstrated that the improved design reduced percolation of water through the landfill cover by a factor of >4 over the conventional design. This decrease in percolation was attributed to a combination of increased evapotranspiration from the plant cover and the effect of a capillary barrier embedded in the enhanced cover profile in diverting water laterally in the cover. The field data are finally discussed in terms of its usefulness for waste management decisions to be made in the future for both new and existing landfills at Los Alumos, NM, and at other semiarid waste disposal sites.