bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spray Drift of Pesticides Arising from Aerial Application in Cotton
Authors: Woods Nicholas , Craig Ian P. , Dorr Gary , Young Brian 
Published: June 2010

ABSTRACTThis paper presents results from field studies carried out during the 1993–1998 Australian cotton (Gossypium hirsutum L.) seasons to monitor off‐target droplet movement 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) insecticide applied to a commercial cotton crop. Averaged over a wide range of conditions, off‐target deposition 500 m downwind of the field boundary was approximately 2% of the field‐applied rate with oil‐based applications and 1% with water‐based applications. Mean airborne drift values recorded 100 m downwind of a single flight line were a third as much with water‐based application compared with oil‐based application. Calculations using a Gaussian diffusion model and the U.S. Spray Drift Task Force AgDRIFT model produced downwind drift profiles that compared favorably with experimental data. Both models and data indicate that by adopting large droplet placement (LDP) application methods and incorporating crop buffer distances, spray drift can be effectively managed.
Endosulfan Transport: I. Integrative Assessment of Airborne and Waterborne Pathways
Authors: Raupach M.R. , Briggs P.R. , Ford P.W. , Leys J.F. , Muschal M. , Cooper B. , Edge V.E. 
Published: June 2010

ABSTRACTTo reduce endosulfan (C9H6O3Cl6S; 6,7,8,9,10,10‐hexachloro‐1,5,5a,6,9,9a‐hexahydro‐6,9‐methano‐2,4,3‐benzodioxathiepin 3‐oxide) contamination in rivers and waterways, it is important to know the relative significances of airborne transport pathways (including spray drift, vapor transport, and dust transport) and waterborne transport pathways (including overland and stream runoff). This work uses an integrated modeling approach to assess the absolute and relative contributions of these pathways to riverine endosulfan concentrations. The modeling framework involves two parts: a set of simple models for each transport pathway, and a model for the physical and chemical processes acting on endosulfan in river water. An averaging process is used to calculate the effects of transport pathways at the regional scale. The results show that spray drift, vapor transport, and runoff are all significant pathways. Dust transport is found to be insignificant. Spray drift and vapor transport both contribute low‐level but nearly continuous inputs to the riverine endosulfan load during spraying season in a large cotton (Gossypium hirsutum L.)‐growing area, whereas runoff provides occasional but higher inputs. These findings are supported by broad agreement between model predictions and observed typical riverine endosulfan concentrations in two rivers.
Olfactory Response to Mushroom Composting Emissions as a Function of Chemical Concentration
Authors: Noble R. , Hobbs P.J. , Dobrovin‐Pennington A. , Misselbrook T.H. , Mead A. 
Published: June 2010

ABSTRACTOdor pollution is a major problem facing mushroom [Agaricus bisporus(Lange) Imbach] compost production. Techniques for quantifying mushroom composting odors are needed to assess the effectiveness of odor control measures. Odor samples were obtained in nalophane bags from 11 mushroom composting sites. Samples were collected 0.2 m downwind from the pre‐wetting heaps (aerated or unaerated) of raw composting ingredients (wheat straw, poultry and horse manures, and gypsum) and subsequent Phase I composting windrows or aerated tunnels. The odor concentrations (OCs) of the samples were assessed using serial dilution olfactometry and the chemical composition of the samples was determined using gas chromatography–mass spectrometry (GC–MS), both 24 h after sampling. Gas detector tubes were used for on‐site measurement of gaseous compounds. Odorants that exceeded their published olfactory detection thresholds by the greatest order of magnitude, in decreasing order, were: H2S, dimethyl sulfide (DMS), butanoic acid, methanethiol, and trimethylamine. Concentrations of NH3were not significantly correlated with OC, and they were not significantly affected by the use of aeration. Aeration reduced the OC and the combined H2S + DMS concentrations by 87 and 92%, respectively. There was a very close correlation (r= 0.948,P< 0.001) between the OC of bag samples and the combined H2S + DMS concentrations, measured on‐site with detector tubes. This relationship was unaffected by the NH3concentration or the type of compost: aerated or unaerated, pre‐wet or Phase I, poultry manure–based or horse and poultry manure–based compost. Prediction of the OC will enable rapid and low‐cost identification of odor sources on mushroom composting sites.
Adsorption of Pesticides onto Quartz, Calcite, Kaolinite, and α‐Alumina
Authors: Clausen L. , Fabricius I. , Madsen L. 
Published: June 2010

ABSTRACTThe fate of pesticides in aquifers is influenced by the small but not insignificant adsorption of pesticides to mineral surfaces. Batch experiments with five pesticides and four minerals were conducted to quantify the contributions to adsorption from different mineral surfaces and compare adsorption characteristics of selected pesticides. Investigated mineral phases included quartz, calcite, kaolinite, and α‐alumina. 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]. Specific surface area and mineral surface charge proved to be important for the adsorption of these pesticides. Detectable adsorption of the anionic pesticides (mecoprop, 2,4‐D, and bentazone) was only measured when positive sites were present on the mineral surface. However, when CaCl2 was added as an electrolyte, a detectable adsorption of mecoprop and 2,4‐D was also measured on kaolinite (which exhibits a negative surface charge), probably due to formation of Ca–pesticide–surface complexes. Adsorption of the uncharged pesticides (atrazine and isoproturon) was detected only on kaolinite. The lack of adsorption on α‐alumina indicates that the uncharged pesticides have a greater affinity for the silanol surface sites (=SiOH) than for the aluminol surface sites (=AlOH) in kaolinite. No measurable effect of ionic strength was found for the uncharged pesticides. The results indicate that quartz and calcite play a smaller role than clay minerals.
Plant Uptake of Cadmium‐109 and Zinc‐65 at Different Temperature and Organic Matter Levels
Authors: Almås Å.R. , Singh B.R. 
Published: June 2010

ABSTRACTThe uptake of 109Cd and 65Zn and their stable isotopes by ryegrass (Lolium multiflorum Lam.), grown on two different soil types, was investigated in climatically controlled growth chambers at 9 and 21°C. The soils were treated with 0 and 4% organic matter (pig [Sus scrofa] manure) and spiked with 109Cd and 65Zn before sowing. The organic matter addition resulted in increased uptake of the 109Cd, Cd, and Zn by ryegrass, but the uptake of 65Zn was decreased. The latter effect was ascribed to isotopic dilution of 65Zn as the amount of stable Zn in the plant tissues increased with the organic matter addition. The effect of temperature was more pronounced than that of organic matter addition, and the uptake of both 109Cd and 65Zn and their stable isotopes was higher in ryegrass grown at 21°C than that grown at 9°C. Results from fractionation and speciation analysis of soil cadmium and zinc were correlated with plant uptake, and there was a good consistency between observed plant uptake and the physico–chemical forms of cadmium and zinc in soil and soil solution presumed to be plant available.
Copper and Calcium Transport through an Unsaturated Soil Column
Authors: Vogeler Iris 
Published: June 2010

ABSTRACTTo determine the relative importance of the physical and chemical factors that influence the movement of heavy metals through soils, leaching experiments were carried out under conditions of constant molarity during unsaturated steady‐state water flow through a Manawatu fine sandy loam (a Dystric Fluventic Eutochrept). The movement and exchange of copper was studied in a binary Cu–Ca system. The movement of the associated anions, namely chloride and sulfate, was also monitored. The measurements were compared with predictions from the convection–dispersion equation (CDE), linked with cation exchange theory. The agreement between the measured and predicted breakthrough of sulfate and copper was good. This indicates that copper retardation in the Manawatu soil is closely related to the cation exchange capacity, and that exchange between Ca and Cu is the main process of Cu retardation in the Manawatu soil. However, copper appeared slightly later in the effluent than predicted, indicating that non‐exchange processes are also involved in copper transport. Measurements of suction cups could also be used to obtain the parameters for the CDE to describe sulfate movement through the soil. Time domain reflectometry (TDR) measurements of the bulk‐soil electrical conductivity could be used to monitor the movement of both sulfate and copper. This indicates that TDR can also be used to monitor cation transport and exchange through the soil, provided the percolating solution causes a sufficient change in the electrical conductivity.
In Situ Bioremediation through Mulching of Soil Polluted by a Copper–Nickel Smelter
Authors: Kiikkilä Oili , Perkiömäki Jonna , Barnette Matthew , Derome John , Pennanen Taina , Tulisalo Esa , Fritze Hannu 
Published: June 2010

ABSTRACTBioremediation of a heavy metal–polluted soil was investigated in a 3‐yr field experiment by adding mulch to a polluted forest floor. The mulch consisted of a mixture of compost and woodchips. The remediation treatment decreased the toxicity of the soil solution to bacteria as determined by the [3H]‐thymidine incorporation technique, that is, by measuring the growth rate of soil bacteria extracted from unpolluted humus after exposing them to soil solution containing heavy metals from the experimental plots. Canonical correlation analysis was performed in order to identify the chemical and microbiological changes in the soil. The pH of the mulched organic layer increased by one unit. The concentration of complexed Cu increased and that of free Cu2+ decreased in the soil solution from the mulch treatment. According to basal respiration and litter decomposition, microbial activity increased during the 3 yr following the remediation treatment. The [3H]‐thymidine incorporation technique was also used to study the growth rate and tolerance of bacteria to Cu. The bacterial growth rate increased and the Cu tolerance decreased on the treated plots. The structure of the microbial community, as determined by phospholipid fatty acid (PLFA) analysis, remained unchanged. The results indicate that remediation of the polluted soil had occurred, and that adding a mulch to the forest floor is a suitable method for remediating heavy metal–polluted soil.
Controlling Nitrate Leaching in Irrigated Agriculture
Authors: Spalding Roy F. , Watts Darrell G. , Schepers James S. , Burbach Mark E. , Exner Mary E. , Poreda Robert J. , Martin Glen E. 
Published: June 2010

ABSTRACTThe impact of improved irrigation and nutrient practices on ground water quality was assessed at the Nebraska Management System Evaluation Area using ground water quality data collected from 16 depths at 31 strategically located multilevel samplers three times annually from 1991 to 1996. The site was sectioned into four 13.4‐ha management fields: (i) a conventional furrow‐irrigated corn (Zea maysL.) field; (ii) a surge‐irrigated corn field, which received 60% less water and 31% less N fertilizer than the conventional field; (iii) a center pivot‐irrigated corn field, which received 66% less water and 37% less N fertilizer than the conventional field; and (iv) a center pivot‐irrigated alfalfa (Medicago sativaL.) field. Dating (3H/3He) indicated that the uppermost ground water was <1 to 2 yr old and that the aquifer water was stratified with the deepest water ∼20 yr old. Recharge during the wet growing season in 1993 reduced the average NO3–N concentration in the top 3 m 20 mg L−1, effectively diluting and replacing the NO3‐contaminated water. Nitrate concentrations in the shallow zone of the aquifer increased with depth to water. Beneath the conventional and surge‐irrigated fields, shallow ground water concentrations returned to the initial 30 mg NO3–N L−1level by fall 1995; however, beneath the center pivot‐irrigated corn field, concentrations remained at ∼13 mg NO3–N L−1until fall 1996. A combination of sprinkler irrigation and N fertigation significantly reduced N leaching with only minor reductions (6%) in crop yield.
A Novel Continuous‐Flow Sequential Extraction Procedure for Metal Speciation in Solids
Authors: Shiowatana J. , Tantidanai N. , Nookabkaew S. , Nacapricha D. 
Published: June 2010

ABSTRACTA continuous‐flow extraction system was developed to speed up, facilitate, and improve the accuracy of the chemical fractionation of metals in solid materials. A three‐step sequential extraction scheme was used to evaluate the novel system by analyzing calcium (Ca), iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in a soil certified reference material (National Institute of Standards and Technology [NIST] SRM 2710). In the proposed system, extraction occurred in a closed chamber through which extractants were passed sequentially. The extracts were collected in a number of subfractions for subsequent flame atomic absorption analysis. Apart from the advantages of simplicity, speed, and less risk of the contamination that flow analysis systems usually possess, the continuous‐flow system can improve the accuracy of chemical fractionation of metals by sequential extraction. The system ensures that extraction is performed at designated pH values without any need of adjustment. Variation of sample weight to chamber volume ratios from 1:12 to 1:40 had no effect on the extractability of the metals studied. In the extraction of the acid soluble fraction, concentrations of acetic acid in the range 0.11 to 0.5 mol L−1 had no significant effect on the amounts of metals extracted, except Fe. Increasing the concentration of hydroxylamine in the reducible fraction step from 0.04 to 0.5 mol L−1 affected the extraction efficiency for Fe, Mn, and Zn. The extraction profile, rather than a single value of extracted concentration, of each element offers additional information about the kinetics of leaching processes and chemical associations between elements in the solid materials.
Evaluation of Leachates from Coal Refuse Blended with Fly Ash at Different Rates
Authors: Stewart B.R. , Daniels W.L. , Zelazny L.W. , Jackson M.L. 
Published: June 2010

ABSTRACTThere is great interest in returning coal combustion products to mining sites for beneficial reuse as liming agents. A column study examined the effects of blending two coal fly ashes with an acid‐forming coal refuse (4% pyritic S). Both fly ashes were net alkaline, but had relatively low neutralizing capacities. One ash with moderate alkalinity (CRF) was bulk blended with coal refuse at 0, 20, and 33% (w/w), while another lower alkalinity ash (WVF) was blended at 0, 5, 10, 20, and 33% (w/w). The columns were leached (unsaturated) weekly with 2.5 cm of simulated precipitation for >150 wk. Where high amounts of ash alkalinity (>20% w/w) were mixed with the coal refuse, pyrite oxidation was controlled and leachate pH was >7.0 with low metal levels throughout the study. At lower rates of alkalinity loading, trace metals were sequentially released from the WVF ash as the 5, 10, and 20% treatments acidified due to pyrite oxidation. Lechate metals increased in proportion to the total amounts applied in the ash. In this strongly acidic environment, metals such as Mn, Fe, and Cu were dissolved and leached from the ash matrix in large quantities. If ash is to be beneficially reused in the reclamation of acid‐producing coal refuse, the alkalinity and potential acidity of the materials must be balanced through the appropriate addition of lime or other alkaline materials to the blend. Highly potentially acidic refuse material, such as that used here, may not be suitable for ash/refuse codisposal scenarios.
Denitrification at a Long‐Term Forested Land Treatment System in the Piedmont of Georgia
Authors: Meding S.Mercer , Morris Lawrence A. , Hoover Coeli M. , Nutter Wade L. , Cabrera Miguel L. 
Published: June 2010

ABSTRACTSpray irrigation of forested land can provide an effective system for nutrient removal and treatment of municipal wastewater. Evolution of N2+ N2O from denitrifying activity is an important renovation pathway for N applied to forested land treatment systems. Federal and state guidance documents for design of forested land treatment systems indicate the expected range for denitrification to be up to 25% of applied N, and most forest land treatment systems are designed using values from 15 to 20% of applied N. However, few measurements of denitrification following long‐term wastewater applications at forested land treatment sites exist. In this study, soil N2+ N2O–N evolution was directly measured at four different landscape positions (hilltop, midslope, toe‐slope, and riparian zone) in a forested land treatment facility in the Georgia Piedmont that has been operating for more than 13 yr. Denitrification rates within effluent‐irrigated areas were significantly greater than rates in adjacent nonirrigated buffer zones. Rates of N2+ N2O–N evolved from soil in irrigated forests ranged from 5 to 10 kg ha−1yr−1N on the three upland landscape positions and averaged 38 kg ha−1yr−1N within the riparian zone. The relationship between measured riparian zone denitrification rates and soil physical and chemical properties was poor. The best relationship was with soil temperature, with anr2of 0.18. Overall, on a landscape position weighted basis, only 2.4% of the wastewater‐applied N was lost through denitrification.
Acidification–Neutralization Processes in a Lignite Mine Spoil Amended with Fly Ash or Limestone
Authors: Seoane S. , Leirós M.C. 
Published: June 2010

ABSTRACTA laboratory experiment was conducted to investigate the long‐term effects of amending sulfide‐rich lignite mine spoil with fly ash (originating from a coal‐fired power station and largely comprised of aluminosilicates) and/or agricultural limestone. The experiment was carried out with soil moisture maintained at field capacity or alternate cycles of wetting and drying. Results obtained suggest that the principal acidification processes were oxidation of sulfide and formation of hydroxysulfate (FeOHSO4), whereas the main neutralization processes were weathering of aluminosilicates in fly ash–treated samples and dissolution of calcium carbonate in limestone‐treated samples. The highest dose of limestone rapidly raised the pH of the spoil, but this increase was not maintained throughout the one‐year experiment. In contrast, fly ash–treated samples showed a more sustained increase in pH, attributable to the gradual weathering of aluminosilicates. The best results (i.e., good short‐ and long‐term neutralization) were obtained in samples treated with both fly ash and limestone. The low liming capacity of the fly ash (47.85 cmol kg−1) means that it must be used in large quantities, an advantage in achieving the further aim of disposing of the fly ash.
Mechanisms of Nutrient Attenuation in a Subsurface Flow Riparian Wetland
Authors: Casey Ryan E. , Taylor M. D. , Klaine Stephen J. 
Published: June 2010

ABSTRACTRiparian wetlands are transition zones between terrestrial and aquatic environments that have the potential to serve as nutrient filters for surface and ground water due to their topographic location. We investigated a riparian wetland that had been receiving intermittent inputs of NO−3 and PO3−4 during storm runoff events to determine the mechanisms of nutrient attenuation in the wetland soils. Few studies have shown whether infrequent pulses of NO−3 are sufficient to maintain substantial denitrifying communities. Denitrification rates were highest at the upstream side of the wetland where nutrient‐rich runoff first enters the wetland (17–58 μg N2O–N kg soil−1 h−1) and decreased further into the wetland. Carbon limitation for denitrification was minor in the wetland soils. Samples not amended with dextrose had 75% of the denitrification rate of samples with excess dextrose C. Phosphate sorption isotherms suggested that the wetland soils had a high capacity for P retention. The calculated soil PO3−4 concentration that would yield an equilibrium aqueous PO3−4 concentration of 0.05 mg P L−1 was found to be 100 times greater than the soil PO3−4 concentration at the time of sampling. This indicated that the wetland could retain a large additional mass of PO3−4 without increasing the dissolved PO3−4 concentrations above USEPA recommended levels for lentic waters. These results demonstrated that denitrification can be substantial in systems receiving pulsed NO−3 inputs and that sorption could account for extensive PO3−4 attenuation observed at this site.
Aluminum Output Fluxes from Forest Ecosystems in Europe: A Regional Assessment
Authors: Dise N. B. , Matzner E. , Armbruster M. , MacDonald J. 
Published: June 2010

ABSTRACTData from 89 forested catchments and plots across Europe were used to define empirical relationships between aluminum leaching and input fluxes of major ions, output fluxes of major ions, ecosystem parameters such as soil pH, and combinations of these. Forests that release dissolved Al to seepage or surface waters are located primarily in areas receiving the highest loading of acid rain, and the output flux of Al shows the highest correlations to the throughfall flux of inorganic nitrogen, the output fluxes of NO−3, H+, and SO2−4, and the mineral soil pH. If the speciation of Al is taken to be Al3+ (an overestimate), Al is released in a nearly 1:1 molar charge ratio with the sum of NO−3 and SO2−4 in runoff or seepage water over a wide range of base‐poor bedrock types and acid deposition across Europe. The empirical data point to a threshold range of N deposition of 80 to 150 mmolc N m−2 yr−1 and a (less clearly defined) range of S deposition of 100 to 200 mmolc SO2−4 m−2 yr−1 above which Al released from forests exceeds 100 mmolc Al m−2 yr−1 Within this threshold range, the sites that release little or no dissolved Al are those that continue to assimilate input N and/or have high soil pH (>4.5).