bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient Conversions by Photosynthetic Bacteria in a Concentrated Animal Feeding Operation Lagoon System
Authors: Sund J.L. , Evenson C.J. , Strevett K.A. , Nairn R.W. , Athay D. , Trawinski E. 
Published: June 2010

ABSTRACTA diurnal examination was conducted to determine the effect of photosynthetic bacteria on nutrient conversions in a two‐stage concentrated animal feeding operation (CAFO) lagoon system in west‐central Oklahoma. Changes in nutrients, microbial populations, and physical parameters were examined at three depths (0, 1.5, and 3.0 m) every 3 h over a 36‐h period. The south lagoon (SL) was anaerobic (dissolved oxygen [DO] = 0.09 ± 0.12 mg/L) while the north lagoon (NL) was facultative (DO ranged from 4.0–0.1 mg/L over 36‐h period). Negative sulfide–sulfate (−0.85) and bacteriochlorophyll a (bchl a)–sulfate (−0.83) correlations, as well as positive bchl a–sulfide (0.87) and light intensity (I)–bchl a (0.89) correlations revealed that the SL was dominated by sulfur conversions driven by the photosynthetic purple sulfur bacteria (PSB). The correlation data was supported by diurnal trends for sulfate, sulfide, and bchl a Both nitrogen and sulfur conversions played a role in the NL; however, nitrogen conversions appeared to dominate this system because of the activity of cyanobacteria. This was shown by positive chlorophyll a (chl a)–I (0.91) and chl a–nitrate (0.98) correlations and the negative correlation between ammonium and nitrite (−0.88). Correlation data was further supported by diurnal trends observed for chl a, DO, and ammonium. For both lagoons, the dominant photosynthetic microbial species determined which nutrient conversion processes were most important.
Aging Effects on Cadmium Transport in Undisturbed Contaminated Sandy Soil Columns
Authors: Seuntjens P. , Tirez K. , Šimůnek J. , van Genuchten M.Th. , Cornelis C. , Geuzens P. 
Published: June 2010

ABSTRACTLimited information is available on the effects of contaminant aging (i.e., the contact time of Cd with the soil) on Cd transport in soils. We conducted displacement experiments in which indigenous Cd and freshly applied Cd were leached simultaneously from undisturbed samples of three Spodosol horizons. Sorption of Cd was described using Freundlich isotherms, whereas transport was described as a convection–dispersion process. Parameter optimization analysis using a mobile–immobile transport model applied to nonsorbing tracer displacement data showed that 16 to 22% of the water in the columns was immobile. The low dimensionless mass transfer coefficients in the mobile–immobile model were indicative of diffusion‐limited transfer between mobile and immobile water, and hence physical nonequilibrium. A two‐site kinetic sorption model could be fitted closely to breakthrough curves of the non‐aged Cd for three soil horizons. No conclusive evidence was found that contaminant aging in soil affects cadmium transport. On the one hand, predictions of aged Cd leaching, using parameters estimated from displacement experiments with non‐aged Cd, differed from those for the aged Cd in the E horizon. On the other hand, no meaningful differences in transport behavior between aged and non‐aged Cd were found for the humus Bh and Bh/C horizons. The two‐site kinetic rate coefficient αc was found to depend on water flux, further indicating that mass transfer between sorption sites and the liquid is limited by diffusion rather than by kinetic sorption.
Off‐Site Movement of Endosulfan from Irrigated Cotton in New South Wales
Authors: Kennedy I.R. , Sánchez‐Bayo F. , Kimber S.W. , Hugo L. , Ahmad N. 
Published: June 2010

ABSTRACTThe fate and transport of endosulfan (6,7,8,9,10,10‐hexachloro‐1,5,5a,6,9,9a‐hexahydro‐6,9‐methano‐2,4,3‐benzodioxathiepin 3‐oxide) applied to cotton (Gossypium hirsutum L.) fields were studied throughout three consecutive years on two selected locations in New South Wales (Australia). Rates of dissipation from foliage and soil, volatilization from the field, and transport of residues in irrigation and/or storm runoff waters were measured in order to estimate a total field balance. Dissipation of endosulfan from both foliage and soil is best explained by a two‐phase process rather than by a first‐order decay. Half‐lives of total endosulfan toxic residues (α‐ and β‐endosulfan and the sulfate product) in the first phase were 1.6 d in foliage and 7.1 d in soil, and could be explained by the rapid volatilization of the parent isomers in the first 5 d (up to 70% of endosulfan volatilizes). In the second phase, half‐lives were 9.5 d in foliage and 82 d in soil, mostly due to the persistence of the sulfate product. Concentration of endosulfan residues in runoff water varied from 45 to 2.5 μg L−1 depending on the residue levels present on field soil at the time of the irrigation or storm events. These in turn are related to the total amounts applied, the cotton canopy cover at application, and the time since last spraying. Most of the endosulfan in runoff was found in the water phase (80%), suggesting it was bound to colloidal matter. Total endosulfan residues in runoff for a whole season accounted for no more than 2% of the pesticide applied on‐field.
Simulating Endosulfan Transport in Runoff from Cotton Fields in Australia with the GLEAMS Model
Authors: Connolly R.D. , Kennedy I.R. , Silburn D.M. , Simpson B.W. , Freebairn D.M. 
Published: June 2010

ABSTRACTEndosulfan (6,7,8,9,10,10‐hexachloro‐1,5,5a,6,9,9a‐hexahydro‐6,9‐methano‐2,4,3‐benzodioxathiepin 3‐oxide), a pesticide that is highly toxic to aquatic organisms, is widely used in the cotton (Gossypium hirsutum L.) industry in Australia and is a risk to the downstream riverine environment. We used the GLEAMS model to evaluate the effectiveness of a range of management scenarios aimed at minimizing endosulfan transport in runoff at the field scale. The field management scenarios simulated were (i) Conventional, bare soil at the beginning of the cotton season and seven irrigations per season; (ii) Improved Irrigation, irrigation amounts reduced and frequency increased to reduce runoff from excess irrigation; (iii) Dryland, no irrigation; (iv) Stubble Retained, increased soil cover created by retaining residue from the previous crop or a specially planted winter cover crop; and (v) Reduced Sprays, a fewer number of sprays. Stubble Retained was the most effective scenario for minimizing endosulfan transport because infiltration was increased and erosion reduced, and the stubble intercepted and neutralized a proportion of the applied endosulfan. Reducing excess irrigation reduced annual export rates by 80 to 90%, but transport in larger storm events was still high. Reducing the number of pesticide applications only reduced transport when three or fewer sprays were applied. We conclude that endosulfan transport from cotton farms can be minimized with a combination of field management practices that reduce excess irrigation and concentration of pesticide on the soil at any point in time; however, discharges, probably with endosulfan concentrations exceeding guideline values, will still occur in storm events.
Fate and Toxicity of Endosulfan in Namoi River Water and Bottom Sediment
Authors: Leonard Alex W. , Hyne Ross V. , Lim Richard P. , Leigh Kellie A. , Le Jiawei , Beckett Ronald 
Published: June 2010

ABSTRACTEndosulfan (6,7,8,9,10,10,‐hexachloro‐1,5,5a,6,9,9a‐hexahydro‐6,9‐methano‐2,4,3‐benzodioxathiepine‐3‐oxide) sorption (standardized to 1% total organic carbon and dry weight) was significantly (P < 0.05) more concentrated on the large (>63 μm) particle fraction compared with smaller size fractions (<5 μm and 5–24 μm) of bottom sediments from the Namoi River, Australia. Following completion of the particle size fractionation (6 to 12 wk) and a sediment toxicity assessment (2 wk), the sediments showed large decreases in concentrations of α‐endosulfan that coincided with an increase in endosulfan sulfate concentrations and minimal changes in β‐endosulfan concentrations. In the Namoi River, similar patterns were observed in the composition of total endosulfan in monthly measurements of bottom sediments and in passive samplers placed in the water column following runoff from cotton (Gossypium hirsutum L.) fields. The toxicity of endosulfan sulfate in river water indicated by the nymphs of the epibenthic mayfly Jappa kutera, was more persistent than the α‐ and β‐endosulfan parent isomers due to its longer half‐life. This suggests that endosulfan sulfate would contribute most to previously observed changes in population densities of aquatic biota. Measured concentrations of total endosulfan in river water of up to 4 μg L−1 following storm runoff, exceed the range of the 96‐h median lethal concentration (LC50) values in river water for both α‐endosulfan (LC50 = 0.7 μg L−1; 95% confidence interval [CI] = 0.5 to 1.1) and endosulfan sulfate (LC50 = 1.2 μg L−1; 95% CI = 0.4 to 3.3). In contrast, the 10‐d LC50 value for total endosulfan in the sediment toxicity test (LC50 = 162 μg kg−1; 95% CI = 120 to 218 μg kg−1) was more than threefold higher than the highest measured concentration of total endosulfan in field samples of bottom sediment (48 μg kg−1). This suggests that pulse exposures of endosulfan in the water column following storm runoff may be more acutely toxic to riverine biota than in contaminated bottom sediment.
A Micrometeorological Technique to Monitor Total Hydrocarbon Emissions from Landfarms to the Atmosphere
Authors: Ausma Sandra , Edwards Grant C. , Wong Edwina K. , Gillespie Terry J. , Fitzgerald‐Hubble Colleen R. , Halfpenny‐Mitchell Laurie , Mortimer Wendy P. 
Published: June 2010

ABSTRACTLandfarming is used to treat petroleum hydrocarbon–contaminated soils and a variety of waste streams from industrial operations. Wastes are applied to a soil surface and indigenous soil microorganisms utilize the hydrocarbons in the applied waste as a carbon source for metabolism, thereby biodegrading the applied material. Concerns have been expressed that abiotic losses, such as volatilization, play a significant role in hydrocarbon reduction within the soil. To assist in better defining atmospheric releases of total hydrocarbons from landfarms treating petroleum hydrocarbons, a flux gradient micrometeorological approach was developed and integrated with a custom‐built total hydrocarbon detector, and a novel air sampling system and averaging algorithm. The micrometeorological technique offers unobtrusive spatially averaged real‐time continuous measurements, thereby providing a time history of emissions. This provides opportunities to investigate mechanisms controlling emissions and to evaluate landfarm management strategies. The versatility of the technique is illustrated through measurements performed at a remote landfarm used to treat diesel fuel–contaminated soil in northern Ontario and during routine operations at two active refinery landfarms in southwestern Ontario.
Effect of Land Use on Methane Flux from Soil
Authors: Chan A.S.K. , Parkin T.B. 
Published: June 2010

ABSTRACTThe precise effects of natural and disturbed terrestrial systems on the atmospheric CH4pool are uncertain. This study was conducted to quantify and compare CH4fluxes from a variety of ecosystems in central Iowa. We investigated agricultural systems under different management practices, a hardwood forest site, native and restored prairies, and a municipal landfill. Flux measurements were obtained using a closed‐chamber method, and measurements were compiled by sampling over the 1993 and 1994 growing seasons. In 1993, most of the agricultural sites were net CH4producers with cumulative CH4fluxes ranging from −0.02 to 3.19 g m−2over the 258‐d sampling season, while the natural ecosystems were net CH4consumers, with cumulative seasonal fluxes ranging from −0.27 to −0.07 g m−2258 d−1In 1994, only the landfill and the agricultural site treated with broadcast liquid swine manure (LSM) were net CH4producers, while the remainder of the natural and agricultural ecosystems were net CH4consumers, with mean seasonal flux rates ranging from −0.43 to −0.008 g m−2271 d−1We hypothesize that the differences in CH4fluxes between the two years are due to differences in rainfall. To illustrate the integration between land use and CH4flux, we computed an area‐weighted soil CH4flux for the state of Iowa. Our calculations yielded a net average soil CH4flux of 139000 Mg CH4for 1993 and 1994.
Atrazine, Isoproturon, Mecoprop, 2,4‐D, and Bentazone Adsorption onto Iron Oxides
Authors: Clausen Liselotte , Fabricius Ida 
Published: June 2010

ABSTRACTIron oxides are important components influencing the adsorption of various inorganic and organic compounds in soils and sediments. In this study the adsorption on iron oxides of nonionic and ionic pesticides was determined as a function of solution pH, ionic strength, and pesticide concentration. The investigated iron oxides included two‐line ferrihydrite, goethite, and lepidocrocite. Selected pesticides comprised atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine), isoproturon [3‐(4‐isopropylphenyl)‐1,1‐dimethylurea)], mecoprop [(RS)‐2‐(4‐chloro‐2‐methylphenoxy)propionic acid], 2,4‐D (2,4‐dichlorophenoxyacetic acid), and bentazone [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4‐(3H)‐one 2,2‐dioxide]. The adsorption of the nonionic pesticides (atrazine and isoproturon) was insignificant, whereas the adsorption of the acidic pesticides (mecoprop, 2,4‐D, and bentazone) was significant on all investigated iron oxides. The adsorption capacity increased with decreasing pH, with maximum adsorption reached close to the pKa values. The addition of CaCl2 in concentrations from 0.0025 to 0.01 M caused the adsorption capacity to diminish. The adsorption of bentazone was significantly lower than the adsorption of mecoprop and 2,4‐D, illustrating the importance of a carboxyl group in the pesticide structure. The adsorption capacity on the iron oxides increased in the order: lepidocrocite < goethite < two‐line ferrihydrite. The maximum adsorption capacities of mecoprop and 2,4‐D on goethite were found to be equivalent to the site density of singly coordinated hydroxyl groups on the faces of the dominant {110} form, suggesting that singly coordinated hydroxyl groups are responsible for adsorption. Differences in adsorption capacities between iron oxides can be explained by differences in the surface site density of singly coordinated hydroxyl groups. The maximum measured adsorption capacity of mecoprop on two‐line ferrihydrite was equivalent to 0.2 mol/mol Fe.
Photosynthesis, Chlorophyll Integrity, and Spectral Reflectance in Lichens Exposed to Air Pollution
Authors: Garty J. , Tamir O. , Hassid I. , Eshel A. , Cohen Y. , Karnieli A. , Orlovsky L. 
Published: June 2010

ABSTRACTThe major objective of the present study was to identify the relationship of physiologial parameters of the photosynthetic system with the elemental content of the lichen Ramalina lacera (With.) J.R. Laund. Thalli of R. lacera were collected in an unpolluted site and transplanted in a national park and an industrial region in Israel for 8 mo. Analyses of photosynthetic activity, chlorophyll integrity, spectral reflectance, and amount of 11 metals were performed after this period of exposure. The normalized difference vegetation index (NDVI), indicative of the spectral reflectance response of the thallus, correlated with photosynthetic rate and chlorophyll and K content and correlated inversely with amounts of Ba, Cr, Cu, and Ni. The NDVI appears to enable the detection of early signs of pollutant‐induced stress before changes in other physiological parameters become apparent. Elevated amounts of Cr, Cu, Fe, Mn, Ni, and Zn in lichens transplanted to an industrial area and the correlation of Mn and Ni, Mn and V, Ni and V, Fe and Mn, Fe and V, and Fe and Zn point for the greater part to metal processing in a steel smelter. Correlations of Cr and Ni, Cu and Ni, Zn and Cu, Cu and Mn, and Zn and Ni could be related to metal processing in the industrial area but indicate also vehicular activity as a possible originator.
Timing of Phosphorus Fertilizer Application within an Irrigation Cycle for Perennial Pasture
Authors: Bush Belinda J. , Austin Nicholas R. 
Published: June 2010

ABSTRACTIrrigated pastures are significant contributors of phosphorus (P) to inland watercourses, with much of the P coming from applied fertilizer. It was hypothesized that the timing of P fertilizer application relative to irrigation regulates P concentrations in runoff and infiltrating water. To test this hypothesis, a two‐by‐two factorial experiment was conducted on twelve 8‐ × 30‐m border‐irrigated bays growing perennial pasture. Phosphorus fertilizer in the form of single superphosphate (44 kg P ha−1) was surface‐broadcast onto the bays when the nominal change in soil water deficit reached 0 or 50 mm (U.S. Class A pan evaporation minus rainfall). Following fertilizer application, the bays were again irrigated when the nominal soil water deficit between fertilizing and the subsequent irrigation reached either 0 or 50 mm. The volume of water applied, runoff volume, and changes in soil water content were recorded for the three irrigations following fertilizer application. Total phosphorus (TP) and filtrable reactive phosphorus (FRP, <0.45 μm) concentrations in runoff and at depths of 0.1, 0.3, and 0.6 m in the soil were also measured. Soil water content at fertilizer application had less effect on P concentrations in runoff and soil water than the additional time between fertilizing and irrigating. By allowing a deficit of 50 mm between fertilizer application and irrigation, the average concentration of P in runoff and moving below a soil depth of 0.1 m was approximately halved. To maximize fertilizer use efficiency and minimize environmental effects, a delay should occur between applying P fertilizer and irrigating perennial pasture.
Effects of Alum and Aluminum Chloride on Phosphorus Runoff from Swine Manure
Authors: Smith D.R. , Moore P.A. , Griffis C.L. , Daniel T.C. , Edwards D.R. , Boothe D.L. 
Published: June 2010

ABSTRACTPhosphorus (P) runoff from fields fertilized with swine (Sus scrofa domesticus) manure may contribute to eutrophication. The objective of this study was to evaluate the effect of aluminum sulfate (alum) and aluminum chloride applications to swine manure on P runoff from small plots cropped to tall fescue (Festuca arundinacea Shreb.). There were six treatments in this study: (i) unfertilized control plots, (ii) untreated manure, (iii) manure with alum at 215 mg Al L−1, (iv) manure with aluminum chloride at 215 mg Al L−1, (v) manure with alum at 430 mg Al L−1, and (vi) manure with aluminum chloride at 430 mg Al L−1 Manure application rates were equivalent to approximately 125 kg N ha−1 Alum and aluminum chloride additions lowered soluble reactive phosphorus (SRP) levels from about 130 mg P L−1 to approximately 30 mg P L−1 at low rates. At high rates, SRP levels in swine manure were around 1 mg P L−1 Soluble reactive P concentrations in runoff were 5.50, 3.66, 3.00, 0.87, 0.87, and 0.55 mg P L−1, for normal manure, low alum, low aluminum chloride, high alum, high aluminum chloride, and unfertilized control plots, respectively. Hence, high alum and aluminum chloride reduced SRP concentrations in runoff by 84% and were not statistically different from SRP concentrations in runoff from unfertilized control plots. These data indicate that treating swine manure with alum or aluminum chloride could result in significant reductions in nonpoint‐source P runoff.
Aerosol Chemical and Optical Properties during the Mt. Zirkel Visibility Study
Authors: Watson John G. , Chow Judith C. , Lowenthal Douglas H. , Cahill Catherine F. , Blumenthal Donald L. , Richards L.Willard , Jorge Helena González 
Published: June 2010

ABSTRACTAerosol chemical and optical properties were measured near the Mt. Zirkel Wilderness Area in northwestern Colorado. Six‐hour PM2.5 (particles with aerodynamic diameters less than 2.5 μm) mass concentrations and PM2.5 dry particle light scattering at 550 nm averaged 4.6 μg m−3 and 8.6 Mm−1, respectively. Sulfates, organic carbon, and geological material were the principle components of particle mass and light scattering. Hygroscopic growth was consistent with that expected for ammonium sulfate aerosols. Size distributions derived from three‐wavelength (i.e., 450, 550, and 700 nm) nephelometer data were similar to those measured in other remote areas of the western USA. Quasi‐dry chemical light scattering efficiencies derived using Mie theory were 3.6 m2 g−1 for organic carbon, 2.5 m2 g−1 for sulfates (ammonium sulfate and ammonium bisulfate), 2.6 m2 g−1 for ammonium nitrate, and 1.76 m2 g−1 for geological material. These values are lower than but consistent with previously reported results. Realistic efficiencies could not be derived using the multiple linear regression (MLR) approach.
Chemical Immobilization of Lead, Zinc, and Cadmium in Smelter‐Contaminated Soils Using Biosolids and Rock Phosphate
Authors: Basta N.T. , Gradwohl R. , Snethen K.L. , Schroder J.L. 
Published: June 2010

ABSTRACTChemical immobilization, an in situ remediation method where inexpensive chemicals are used to reduce contaminant solubility in contaminated soil, has gained attention. We investigated the effectiveness of lime‐stabilized biosolid (LSB), N‐Viro Soil (NV), rock phosphate (RP), and anaerobic biosolid (AB) to reduce extractability and plant and gastrointestinal (GI) bioavailability in three Cd‐, Pb‐, and Zn‐contaminated soils from smelter sites. Treated (100 g kg−1 soil) and control soils were incubated at 27°C and −0.033 MPa (−0.33 bar) water content for 90 d. The effect of soil treatment on metal extractability was evaluated by sequential extraction, on phytoavailability by a lettuce bioassay (Lactuca sativa L.), on human GI availability of Pb from soil ingestion by the Physiologically Based Extraction Test. The largest reductions in metal extractability and phytoavailability were from alkaline organic treatments (LSB and NV). Phytotoxic Zn [1188 mg Zn kg−1 extracted with 0.5 M Ca(NO3)2] in Blackwell soil (disturbed soil) was reduced by LSB, NV, and RP to 166, 25, and 784 mg Zn kg−1, respectively. Rock phosphate was the only treatment that reduced GI‐available Pb in both gastric and intestinal solutions, 23 and 92%, respectively. Alkaline organic treatments (LSB, NV) decreases Cd transmission through the food chain pathway, whereas rock phosphate decreases risk from exposure to Pb via the soil ingestion pathway. Alkaline organic treatments can reduce human exposure to Cd and Pb by reducing Zn phytotoxicity and revegetation of contaminated sites.