bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decompostion of Hydrazine in Aqueous Solutions
Authors: Moliner Ana M. , Street J. J. 
Published: July 2010

AbstractThe effects of several environmental factors on the fate of hydrazinc in aqueous systems were studied. In aqueous systems, the primary mechanism of hydrazine (N2H4) degradation appears to be a four‐electron oxidation to N2 gas by oxygen. The oxidation rate was very slow in distilled water but increased with the addition of catalysts such as Cu(II) and phosphate ions. Conditions that accelerated the formation of the hydrazyl radical, the first step in hydrazine oxidation, increased the proportion of one‐electron oxidation. This resulted in increasing the formation of ammonia as one of the degradation products. Ammonia evolution was correlated with Cu(II) and phosphate ion concentrations, as well as with temperature. Hydrazine oxidation was primarily dependent on the rate of the oxygen diffusion from the gas phase.
Behavior of Aromatic Surfactants and PCBs in Sludge‐Treated Soil and Landfills
Authors: Marcomini A. , Capel P. D. , Lichtensteiger Th. , Brunner P. H. , Giger W. 
Published: July 2010

AbstractThe aromatic surfactant linear alkylbenzenesulphonate (LAS) and the refractory biointermediates of nonylphenol polyethoxylates (NPEO), namely nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO), together with polychlorinated biphenyls (PCBs) and organic carbon (OC), were determined in sludge‐treated soil at 19 time intervals during a 1‐yr period after sludge application. The initial concentrations of LAS, NP, NP1EO, and NP2EO in the amended soil were 45, 4.7, 1.1 and 0.1 mg/kg (dry wt.); the residual mean concentrations, 320 d after the last sludge application, were 5, 0.5, 0.1, and 0.01 mg/kg for LAS, NP, NP1EO, and NP2EO, respectively. All of the aromatic surfactants demonstrated a very fast decrease in concentration (>80% within the first month), presumably due to biodegradation, but all of them exhibited a residual concentration in the soil after 320 d. Total PCBs and OC showed no significant soil concentration changes, within the error of analysis, over this same 1‐yr period. The pattern of PCB congeners also demonstrated no substantial changes, indicating that they all behave very similarly. The LAS and PCBs were also measured in samples from dated ponds of four sludge‐only landfills which were in use at different times over the past 30 yr. The increase in the use of LAS and decrease in the open use of PCBs was reflected in the sludge pond concentrations at one site where there was a continuous record from 1972 to 1986.
A Semiautomated Instrument for Measuring Total and Radiolabeled Carbon Dioxide Evolution from Soil
Authors: Shelton Daniel R. , Parkin Timothy B. 
Published: July 2010

AbstractThe design and operation of a semiautomated instrument for measuring total and radiolabeled CO2 evolution from soil is described. In the recirculation mode, headspace gases are recirculated in a closed loop through an infrared (IR) detector. After a steady state is achieved, the concentration of total CO2 is read and recorded. In the flush mode, compressed air is used to flush CO2 from the headspace into test tubes containing trapping solution. Radiolabeled carbon dioxide is quantified by counting aliquots of trapping solution in a liquid scintillation counter. The variability associated with the IR detector is 3.6% (coefficient of variation). The trapping efficiency is 100% (±2.0%). The variability associated with two different methods of pesticide application to soil was also investigated. With the slurry method, aliquots of air‐dried soil were added to a pesticide solution [carbofuran(2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl methylcarbamate)] with thorough mixing. With the spray method, the carbofuran solution was applied as an aerosol to soil that had been previously wetted. There was little difference in the variability of total CO2 production between the two methods. The variability associated with 14CO2 evolution from soil (carbofuran hydrolysis), however, was greater with sprayed soil than with slurred soil, suggesting that the slurry method resulted in a more homogenous distribution of pesticide throughout the soil. The low analytical variability associated with measurements of total CO2 and 14CO2 production, as well as the large number of samples that can be accommodated (up to 94 flasks or intact soil cores) make this instrument ideal for the execution of the large screening studies needed to obtain reliable estimates of the spatial variability of rates of pesticide degradation.
The Fate of Nitrogenous Fertilizers Applied to Turfgrass
Authors: Petrovic A. Martin 
Published: July 2010

AbstractMaintaining high quality surface and groundwater supplies is a national concern. Nitrate is a widespread contaminant of groundwater. Nitrogenous fertilizer applied to turfgrass could pose a threat to groundwater quality. However, a review of the fate of N applied to turfgrass is lacking, but needed in developing management systems to minimize groundwater contamination. The discussion of the fate of N applied to turfgrass is developed around plant uptake, atmospheric loss, soil storage, leaching, and runoff. The proportion of the fertilizer N that is taken up by the turfgrass plant varied from 5 to 74% of applied N. Uptake was a function of N release rate, N rate and species of grass. Atmospheric loss, by either NH3 volatilization or denitrification, varied from 0 to 93% of applied N. Volatilization was generally <36% of applied N and can be reduced substantially by irrigation after application. Denitrification was only found to be significant (93% of applied N) on fine‐textured, saturated, warm soils. The amount of fertilizer N found in the soil plus thatch pool varied as a function of N source, release rate, age of site, and clipping management. With a soluble N source, fertilizer N found in the soil and thatch was 15 to 21% and 21 to 26% of applied N, respectively, with the higher values reflecting clippings being returned. Leaching losses for fertilizer N were highly influenced by fertilizer management practices (N rate, source, and timing), soil texture, and irrigation. Highest leaching losses were reported at 53% of applied N, but generally were far less than 10%. Runoff of N applied to turfgrass has been studied to a limited degree and has been found seldom to occur at concentrations above the federal drinking water standard for NO−3. Where turfgrass fertilization poses a threat to groundwater quality, management strategies can allow the turfgrass manager to minimize or eliminate NO−3 leaching.
Plant Responses to Rising Carbon Dioxide and Potential Interactions with Air Pollutants
Authors: Allen L. H. 
Published: July 2010

AbstractAs global population increases and industrialization expands, carbon dioxide (CO2) and toxic air pollutants can be expected to be injected into the atmosphere at increasing rates. This analysis reviews a wide range of direct plant responses to rising CO2, increasing levels of gaseous pollutants, and climate change, and to potential interactions among the factors. Although several environmental interactions on stomata and foliage temperatures are reviewed briefly, a comprehensive review of effects of potential climatic change on plants is not a major objective of this analysis. Research shows that elevated CO2 increases photosynthetic rates, leaf area, biomass, and yield. Elevated CO2 also reduces transpiration rate per unit leaf area, but not in proportion to reduction of stomatal conductance, because foliage temperature tends to rise. With increasing leaf area and foliage temperature, water use per unit land area is scarcely reduced by elevated CO2. Increases in photosynthetic water‐use efficiency are caused primarily by increased photosynthesis rather than reduced transpiration. Gaseous pollutants (O3, SO2, NOx, H2S) affect plants adversely primarily by entry through the stomata. An example calculation showed that reduction in stomatal conductance by doubled CO2 could potentially reduce the effects of ambient O3 and SO2 by 15%. However, information on the interaction of CO2 and air pollutants is scanty. More research is needed on these interactions, because regional changes in air pollutants are occurring concurrently with global changes in CO2.
A Review of the Response of Epicuticular Wax of Conifer Needles to Air Pollution
Authors: Turunen M. , Huttunen S. 
Published: July 2010

AbstractThe effects of air pollutants on the epicuticular wax structure of conifer needles and the ecophysiological consequences of the injuries are reviewed on the basis of published literature and the authors' recent investigations. Degradation of the epicuticular waxes, which appears as a fusion of wax tubes in the epistomatal chambers and finally results in an amorphous appearance of the waxes, is the most common micromorphological injury type observed in studies on the genera Abies, Larix, Picea, and Pinus. The rate of erosion correlates well with the level of air pollution, but clear evidence for the specificity of the symptoms for different air pollutants has not been observed. It is concluded that the erosion of the epicuticular waxes, a phenomenon with a large geographic distribution, is a relevant factor of the multiple forest decline syndrome. Erosion of the waxes can change needle wettability and rain retention. Increased needle wettability and permeability of the cuticles can result in enhanced leaching of nutrients and uptake of pollutants. Increased or decreased stomatal and cuticular diffusion resistance of the needles leads to altered transpiration rates. Due to the changed chemical microenvironment of the needles, the conifers are predisposed to various biotic and abiotic stresses. Because the epicuticular waxes are one of the first targets of a variety of air pollutants, they can widely be used as an early indicator of air pollution effects.
Aluminum Speciation Using Morin: I. Morin and Its Complexes with Aluminum
Authors: Browne B. A. , McColl J. G. , Driscoll C. T. 
Published: July 2010

AbstractIn this and a companion study, we developed a procedure that uses the fluorescing chelating agent morin (2,3,4,5,7‐pentahydroxy‐flavone) to speciate aqueous Al in the acidic pH range. Morin is a pentaprotic acid with five weakly acidic functional groups. However, only the first proton dissociation reaction was found to be significant in the acidic pH range, and a simple monoprotic model (pKal = 5.04) accurately described proton binding. Aluminum and morin formed complexes of 1:1 and 1:2 and/or 1:3 (Al/morin) stoichiometry, but at low total morin concentrations (near 1 µM) only 1:1 species were prevalent. The equilibrium chemistry of 1:1 Al/morin complexes in the acidic pH range was closely described by a parabolic model consistent with the formation of three complexes: AlH4MOR2+, Al(OH)H4MOR+, and Al(OH)2H4MOR0. For Al and six potentially interfering cations, the order of affinity for morin relative to Al in the acidic pH range was approximately as follows: Al > Fe(III) > Cu > Fe(II) > Ca > Mg > Mn = Zn. Formation of competing cation‐morin complexes was enhanced with increasing pH. None of the tested cations formed complexes with morin with fluorescence spectra overlapping the spectra of the Al‐morin complexes.
Aluminum Speciation Using Morin: II. Principles and Procedures
Authors: Browne B. A. , Driscoll C. T. , McColl J. G. 
Published: July 2010

AbstractIn this study we present an analytical technique that uses a dilute aqueous solution of the fluorescing chelating agent morin (2,3,4,5,7‐pentahydroxyflavone) (1 µM) to distinguish between Al species in acidic solutions. Sensitive and accurate speciation estimates were obtained for synthetic solutions containing low concentrations of model Al binding ligands (1 µM F or 0.001 M SO4). Good agreement existed with thermochemical modeling predictions, and accurate equilibrium constants were estimated for AlF2+ and Al(SO4)+. For the F solutions, speciation measurements made with morin were superior to measurements made with the F ion selective electrode. For natural water samples (n = 108) exhibiting a wide range of pH and concentrations of Al binding ligands, the addition of morin did not obscure the subtleties of the Al species distribution. The average redistribution of Al species in the presence of morin was less than 3%, and a correction factor was applied to calculate the species distribution prior to morin addition. The fraction of total Al bound with organic solutes estimated using morin (74%) was significantly higher than in previous studies using other techniques. The magnitude of uncertainties in species concentration estimates, estimated by Monte Carlo simulation, varied with pH, Al concentration, and total morin concentration. For 1 µM morin solutions, maximum uncertainties for major Al species were low (approx. <12%) in the pH range between 3 and 7.
Lake Level Influences on Sediment and Nutrient Retention in a Lakeside Wetland
Authors: Clausen J. C. , Johnson G. D. 
Published: July 2010

AbstractLake levels, sediment and nutrient retention, and flows were studied in a 180‐ha wetland adjacent to Lake Champlain, VT, to assess the role of lake levels on sediment and nutrient retention within the wetland. This wetland received both point and nonpoint sources of nutrients. Input, output, and within‐wetland water samples were collected at 15 sites, and flows were measured nine times in 1983 at lake levels varying over 2 m. The ratio of wetland inflow to outflow was related to changes in lake levels. During spring, the concentrations of total suspended solids, total P, and total Kjeldahl N throughout the wetland were lower than during summer and fall periods. Wetland outlet concentrations decreased with rising lake levels. When wetland inflows exceeded outflow, there was a net mass retention of total suspended solids, total P, and total Kjeldahl N. Exports from the wetland decreased as lake level increased. The sediment and nutrient treatment capacity of this lakeside wetland appeared to be dominated by hydrologic influences.
Release of Radon‐222 by Vascular Plants: Effect of Transpiration and Leaf Area
Authors: Lewis B. G. , MacDonell M.M. 
Published: July 2010

AbstractAt disposal sites for wastes containing radium (Ra), vegetative stabilization may allow escape of radon (Rn) via uptake and mass flow of the gas in the plant transpiration stream. The main objectives of this work were to determine the magnitude and factors of such transport. Corn (Zea mays L.), sunflower (Helianthus annuus L.), and tall fescue (Festuca arundinacea Schreb.) were grown in uranium mill railings solids containing 226Ra (4.4 × 103 Bq kg−1). The quantities of 222Rn released by the plants in a controlled environment chamber were measured in relation to water transpired and leaf areas. The 226Ra and 222Rn in corn xylem liquid, and diffusion of 222Rn across paraffin wax barriers, were also measured. The 222Rn release rates by the plants ranged from about 8 to 28 mBq s−1 m−2 of leaf area, and were unrelated to the quantity of water transpired. Generally, the plants tended to release twice as much radon at 15°C than at 30°C, a phenomenon explained in part by the increased solubility of Rn in water at the lower temperature. We suggest that the bulk of 222Rn released by the plants is taken up by mass flow in water, but at the leaf mesophyll Rn diffuses independently of water, through the entire leaf cross‐section, unimpeded by the cuticle and epicuticular wax. The species of plant does not appear to be a major factor in the quantity of Rn released to the air; rather, the amount of Rn released into the atmosphere from a given area of vegetated land is expected to be in direct proportion to the leaf area index.
Effects of Extraction Methods and Sample Storage on Properties of Solutions Obtained from Forested Spodosols
Authors: Ross Donald S. , Bartlett Richmond J. 
Published: July 2010

AbstractSoil solutions obtained by three methods from Spodosols at a high‐elevation, forested study site were compared. Solutions were extracted by miscible displacement, by centrifugation, and by compressing a soil‐packed syringe. Analyses of pH, inorganic anions, total and reactive Al, and organic C showed few differences between miscible displacement and the syringe‐pressure methods. However, centrifugation at a relative centrifugal force (RCF) of 9700 m s−2 consistently produced solutions with significantly higher pH and F− content than did the other methods. Differences after centrifugation also were found in Cl−, NO−3, SO2−4, but Al, but less frequently. Effect of soil storage time on solutions obtained using the syringe‐pressure technique was studied. Both Oa and Bhs horizon samples showed large increases in solution NO−3 after 24 h of storage at 3°C. During 36 d of storage, NO−3 levels increased by as much as 10‐fold and were accompanied by pH decreases. Measurements in solutions obtained from samples that had been frozen for 36 d were higher than in the original solutions, except for NO−3 and pH. Changes with freezing appeared to be related to large increases in soluble organic C. Our results suggest that soil solution samples should be obtained very quickly after sampling of soils and that high‐speed centrifuge techniques may give erroneous results. The syringe‐pressure method is relatively rapid, simple, and easily performed in the field. However, it may not be practical under dry conditions.
Plant Uptake of Sludge‐Borne PCBs
Authors: O'Connor G. A. , Kiehl D. , Eiceman G.A. , Ryan J.A. 
Published: July 2010

AbstractPlant uptake of sludge‐borne polychlorinated biphenyls (PCBs) (similar to Aroclor 1248) was evaluated in a greenhouse study with two food‐chain crops and a grass species. Polychlorinated biphenyl loading to two soils was varied in one experiment by adding different rates of a municipal sewage sludge heavily contaminated (52 mg kg−1 with PCBs. In a second experiment, Aroclor 1248 was spiked into unamended soils or soils amended with another sludge containing <1 mg kg−1 PCBs. Analysis of PCBs was by GC/MS with a reliable detection limit in plants of 20 µg kg−1 for individual chlorinated classes (tri‐, tetra‐, and pentachlorobiphenyls) and total PCBs. Only carrots (Daucus carota) were contaminated with PCBs, and contamination was restricted to carrot peels. Current USEPA guidelines for land application of sludges based on sludge PCB content are shown to be extremely conservative.
Volatilization of Selenium from Agricultural Evaporation Pond Water
Authors: Thompson‐Eagle E. T. , Frankenberger W. T. 
Published: July 2010

AbstractA major concern in the San Joaquin Valley, CA, is that high levels of Se in agricultural drainage water are concentrating to hazardous levels in evaporation ponds. The primary objective of this study was to determine factors that affect Se biomethylation and thus permanently remove Se directly from evaporation pond water. Pond water samples (14–2000 µg Se L−1) were set up as laboratory mesocosms. The natural formation of dimethylselenide (DMSe) in unamended water was less than 1% of the total Se inventory after 40 d of incubation. No Se methylation took place in autoclaved, unamended pond water. L‐Methionine (10 µM) stimulated DMSe production in nonsterile pond water, and in autoclaved water (1 µM). Increasing the temperature to 35°C and the addition of 1% (wt/wt) glucose with a fungal inoculum, Alternaria alternata, doubled DMSe production over the controls after 25 d of incubation. Carbon sources such as glucose, maltose, sucrose, and galacturonic acid at 2 g C L−1 under ambient conditions slightly enhanced indigenous Se methylation (1.5‐fold). Of the amino acids tested, L‐methionine (0.02 g C L−1) stimulated DMSe evolution from pond water more so than L‐cysteine, L‐cystine, and L‐serine. The proteins, egg albumen, casein, and gluten (2 g C L−1) dramatically increased Se biomethylation causing a 23, 41, and 10% Se loss from the inventory, respectively, after 43 d of incubation. The stimulation of Se volatilization from evaporation pond water through specific amendments could prove to be promising as a field detoxification technique.
Surface‐Facilitated Chemical Degradation of Tetraphenylboron in Soil
Authors: Mills Gary L. , Kaplan Daniel , Schwind Donna , Adriano Domy 
Published: July 2010

AbstractLaboratory studies were conducted to examine the surface‐promoted degradation of tetraphenylboron (TPB) in soil. The results indicated that TPB degrades rapidly in soil and that the processes involved are predominately abiotic reactions. The initial products of degradation of TPB are diphenylborinic acid (DPBA) and biphenyl. A portion of the DPBA produced subsequently degrades to produce boric acid. However, only about 20% of the total B added initially to the soil as TPB was accounted for by the measured species at the end of the experiment. Most of the remaining B appears to be present in moderately stable organic compounds. Comparison of the degradation rates in different soils indicated that the rates in the surface soil were somewhat higher than in the subsoil. The only measured characteristic of these soils that follows a corresponding trend is soil organic matter content. Additional experiments indicated that rates of the initial reaction are inversely related to soil moisture content. Observed reaction products indicate that the initial step in the degradation process is a two‐step oxidation at Lewis acid sites associated with soil component surfaces.
An Ultraviolet Absorbance Method of Estimating the Percent Aromatic Carbon Content of Humic Acids
Authors: Traina Samuel J. , Novak Jeff , Smeck Neil E. 
Published: July 2010

AbstractThe aromatic C content of humic acids strongly influences the complexation of nonpolar organic solutes by humic substances. A rapid method of estimating the aromatic C content of humic acids would be useful in studies of the fate of nonpolar organic solutes in soils and natural waters. The relationship between the UV absorptivity of nine different dissolved humic substances, measured at a wavelength of 272 nm, and their aromatic C content, as determined by 13C CPMAS NMR, was evaluated. The percent aromatic C (determined by NMR) was strongly correlated (r = 0.94) with the UV absorptivity measurements. It is suggested that determinations of UV absorptivity at 272 nm can be used to provide a quantitative estimate of the aromatic C content of dissolved humic acids.
Sensitivity of Tree Seedlings to Aluminum: I. Honeylocust
Authors: Sucoff Edward , Thornton F. C. , Joslin J. D. 
Published: July 2010

AbstractLiterature about the effects of Al on trees is reviewed in this article, emphasizing factors to consider when interpreting how seedling growth responds to Al. This article integrates two soil and two hydroponic studies that examine how honeylocust (Gleditsia triacanthos L.) seedlings respond to Al. The studies determined that honeylocust is the most Al‐sensitive forest tree to have been studied in detail. Plant biomass and root number declined as Al in the soil or hydroponic solution increased. Growth was most consistently related to e{Al3+} ({Al3+} is the Al3+ activity in the solution) or to the ratio of MAL/Ca (MAL is inorganic monomeric Al). In our study root number declined 50% between 0 and 0.05 mM MAL (0 to 0.012 mM {Al3+}). Root weight was also negatively related to root Al and positively related to root Ca. Levels of solution MAL/Ca and {Al3+} associated with more than 20% reductions in honeylocust growth were found in lysimeter solutions collected from a number of forested watersheds. However, such levels are probably not common in the natural edaphic range of honeylocust.