bluuebunny/crossref_metadata_2025_split huggingface dataset:
Partitioning of Heavy Metals in a Soil Contaminated by Slag: A Redistribution Study
Authors: Bunzl K. , Trautmannsheimer M. , Schramel P. 
Published: July 2010

AbstractIn order to interpret reasonably the partitioning of heavy metals in a contaminated soil as observed from applying a sequential extraction procedure, information on possible redistribution processes of the metals during the various extraction steps is essential. For this purpose, sequential extraction (extended Tessier procedure) was used to study the chemical partitioning of Ag, Cu, Ni, Pb, and Zn in a soil contaminated either by a slag from coal firing or by a slag from pyrite roasting. Through additional application of sequential extraction to the pure slags as well as to the uncontaminated soil, it was shown that during the various extraction steps applied to the soil/slag mixtures, substantial redistribution processes of the metals between the slag‐ and soil particles can occur. In many cases, metals ions released during the extraction with acid hydroxylamine or acid hydrogen peroxide are partially readsorbed by solid constituents of the mixture and will therefore be found in the subsequent fractions extracted. As a result, one has to realize that (i) it will be difficult to predict the chemical partitioning of these metals in contaminated soils by investigating pure slags only, and (ii) information on the partitioning of a metal in a slag contaminated soil will not necessarily give any relevant information on the form of this metal in the slag or in the slag/soil mixture, because the redistribution processes during sequential extraction will not be the same as those occurring in the soil solution under natural conditions.
Characterization of Technetium Species Induced in Spinach
Authors: Harms A. V. , Krijger G. C. , van Elteren J. T. , de Goeij J. J. M. 
Published: July 2010

AbstractPlants have the ability to accumulate the long‐lived fission product 99Tc. In this work, an attempt was made to separate and characterize technetium species induced by spinach plants (Spinacia oleracea L.) grown on a TcO−4 containing nutrient solution. Combination of data obtained with selective extraction (ammonium sulfate, acetone, diethyl ether, and 8‐hydroxyquinoline in chloroform) and chromatography (size‐exclusion chromatography and reversed‐phase ion‐pair chromatography) gave us insight into Tc speciation in spinach plants. The following classes of Tc species in spinach leaf homogenate were found after an incubation period of 11 d: TcO−4 (ca. 7%), TcV‐cysteine (ca. 25%), Tc bound to insoluble cell‐wall polysaccharides (ca. 17%), Tc bound to proteins (ca. 26%), and hydrophilic non‐protein Tc species (ca. 25%). These results may yield a new insight into the metabolic pathways of Tc in plants.
Chemical Composition of Leachate of Dairy Manure Mixed with Fluidized Bed Combustion Residue
Authors: Elrashidi M. A. , Baligar V. C. , Korcak R. F. , Persaud N. , Ritchey K. D. 
Published: July 2010

AbstractThis study was initiated to investigate the hypothesis that using Fiuidized Bed Combustion (FBC) residue to stabilize a dairy feedlot surface (DFS) could enhance element attenuation and minimize the environmental impact on water quality. The laboratory leaching experiment included FBC, dairy manure (DM), and DM/FBC treatments. The leaching process consisted of 10 weekly additions of distilled water, each of 460 mL. Using FBC with DM decreased the concentration of most elements (e.g., P, N, K, Ca, Al, Si, Fe, Mn, Cu, Zn, Pb, Cd, Co, Cr, Ni, As, and Se) in the leachate. A decrease ranging from 5.6 to 100% was obtained. The presence of high concentration of dissolved organic matter (DOM) is believed to enhance element attenuation by FBC minerals (e.g., Feo, and Al‐oxides). Several mechanisms involved in this process are proposed: (i) formation of insoluble metal‐organic complexes; (ii) sorption of soluble organic and inorganic species on mineral surfaces; and (iii) precipitation of soluble inorganic species. These mechanisms are discussed in relation to each of the measured elements. On the other hand, using FBC with DM appeared to increase the concentration of B (235%), S (47.3%), and Mg (36.5%) in the leachate. Reactions of DOM with FBC minerals to form soluble organic complexes were suggested to explain B and S increases. The increase in leached Mg could be attributed to the presence of SO2−4. Our results provide evidence that using FBC to stabilize DFS has the advantage of immobilizing a large portion of most elements present in DM leachate.
Some Equilibrium Approaches to Study the Retention and Release of Sulfate in Some Highly Acid German Subsoils
Authors: Ludwig Bernard , Khanna Partap , Prenzel Jürgen 
Published: July 2010

AbstractA decrease in sulfate (SO4) deposition in recent years has been predicted to affect the long‐term changes in soil SO4 dynamics differently, depending upon the equilibrium approaches (sorption isotherms or AlOHSO4 solubility) used. This study reassesses the usefulness of equilibrium approaches using data from batch experiments where the solution concentrations were changed in small steps. Experiments were carried out using five highly acid German subsoils. The approaches included solubilities of SO4 minerals, the classical one‐ and two‐site Langmuir isotherms, an empirical Freundlich isotherm with a pH‐dependent coefficient and modified Langmuir isotherm approaches considering the activity of protons (H+‐dependent Langmuir) or the square of the proton activity ((H+)2‐dependent Langmuir) in the equations. The ion activity product of AlOHSO4 was not constant for most experiments but was a function of the SO4 sorption for all five soils. Dynamics of the retention and release of SO4 in these soils indicated the limitation in the use of one‐ and two‐site Langmuir isotherms considering the theoretical basis behind these isotherms. The (H+)2‐dependent Langmuir isotherm approach described SO4 sorption better than one‐ and two‐site Langmuir isotherms, but not as well as the pH‐dependent Freundlich and the H+‐dependent Langmuir isotherms. For describing SO4 sorption in highly acid soils it is important to include its relationship with protons. It would mean using any of the following approaches: (i) the empirical pH‐dependent Freundlich isotherm, (ii) the H+‐dependent Langmuir isotherm approach, or (iii) an ion activity product of AlOHSO4 as a function of SO4 sorption.
Nitrogen Management Impacts on Yield and Nitrate Leaching in Inbred Maize Systems
Authors: Rasse Daniel P. , Ritchie Joe T. , Peterson W. Richard , Loudon Ted L. , Martin Edward C. 
Published: July 2010

AbstractLittle information is available regarding N management of inbred maize (Zea mays L.), which exports less N than hybrid maize. Nitrate contamination of the groundwater has been a concern in St Joseph County in southwest Michigan where >20 000 ha of seed maize are grown on sand and sandy loam soils. Over application of N fertilizer potentially reduces profits of the local growers and poses a threat to the environment. A field experiment was conducted from 1990 to 1994 to estimate N fertilizer requirements of three different inbred varieties for maximizing yields while minimizing ground water pollution. Yield and N content of grain and stover were analyzed at the end of each growing season. Nitrate leaching was monitored throughout the 5 yr of study by collecting and analyzing drainage flows out of five large field lysimeters. Grain yield was the least responsive to N fertilization, compared with stover biomass, and grain and stover N concentrations. Analyses of yield, NO3‐N leaching and soil N balance indicated that the appropriate fertilization of the P38 mid‐season inbred approximated 108 kg N ha−1. Nitrate leaching out of unfertilized plots reached a threshold of 12 to 15 kg N ha−1 yr−1, during the last 2 yr of treatment. Application of 101 and 202 kg N ha−1 generated an average annual loss of 26 and 60 kg N ha−1, respectively, during the last 2 yr of treatment.
The Promotive Effect of Selenium on Plant Growth as Triggered by Ultraviolet Irradiation
Authors: Hartikainen Helinä , Xue Tailin 
Published: July 2010

AbstractSelenium is known to be important in antioxidation in human and animals, but little attention has been paid to its role in higher plants. Chemically it is a photovoltaic element, and in order to study its effects on plants, ryegrass (Lolium perenne L.) and lettuce (Lactuca sativa L.) were cultivated in a pot experiment without or with H2SeO4 (0.1 and 1.0 mg Se kg−1) under normal light or subjected to UV(B)‐irradiation episodes. Without Se addition, UV(B) diminished markedly the yield of lettuce (by 8%) but not that of ryegrass. The lower Se dosage had no effect on yields under normal light conditions, but in combination with UV(B) it enhanced plant growth. This indicates that UV light acted as a trigger for the growth‐promoting effect of Se. The higher Se dosage was toxic to plants, but the toxicity was alleviated under UV(B). The positive interaction between the high‐energy light and Se was manifested also as increased concentrations of nucleic acids and soluble proteins. The synergistic effect was partly attributable to the antioxidative function of Se, shown as inhibition of lipid peroxidation and promotion of glutathione peroxidase (GSH‐Px) activity. Some other possible mechanisms of the positive action of Se are discussed.
Temperature and Moisture Effects on Fumigant Degradation in Soil
Authors: Gan J. , Papiernik S. K. , Yates S. R. , Jury W. A. 
Published: July 2010

AbstractRecent discovery of the contribution of methyl bromide fumigation to stratospheric ozone depletion has revealed our limited understanding of the environmental processes of fumigants. For instance, little is known about fumigant degradation in soil under high temperature or low moisture conditions that prevail near the soil surface during fumigation. In this study we determined the interaction of soil temperature and moisture with degradation of 1,3‐dichloropropene (1,3‐D) and methyl isothiocyanate (MITC) for extended soil temperature and moisture ranges. Fumigant degradation increased 5 to 12 times when temperature increased from 20 to 50°C. It was further shown that chemical transformation of fumigants always increased with increasing temperature, but temperature effects on microbial degradation were fumigant dependent. The relative contribution of microbial degradation to the overall fumigant degradation was highest for the soil with highest organic matter content, and was greater for MITC than for 1,3‐D isomers. When the temperature was >30°C, microbial degradation of 1,3‐D was substantially suppressed, while that of MITC was greatly stimulated. As soil moisture content increased, 1,3‐D degradation accelerated, but that of MITC decreased. The specific responses of fumigant degradation to temperature and moisture variations should be considered when describing their transport in the environment, and also may be used for designing fumigation practices that allow reduced atmospheric emissions.
Oxyanion Sorption and Surface Anion Exchange by Surfactant‐Modified Clay Minerals
Authors: Li Zhaohui 
Published: July 2010

AbstractIn this study the sorption of nitrate (NO−3) and chromate (CrO2−4) from aqueous solution by surfactant‐modified clay minerals was investigated. Both the sorption and desorption of oxyanions were found to follow a Langmuir sorption isotherm. In general, the sorption affinity is higher for chromate than for nitrate, reflecting that the interaction between the divalent anions and the surfactant bilayer is stronger than that between the monovalent anions and the surfactant bilayer. Surfactant‐modified kaolinite has a higher sorption capacity for chromate. The sorption capacities for chromate and nitrate are equal for surfactant‐modified illite while the sorption capacity for nitrate is higher for surfactant‐modified smectite. Desorption by water revealed that chromate sorption was irreversible, while nitrate sorption was slightly reversible. In a mixed solution system, nitrate and chromate compete for the same sorption sites, resulting in a decrease in sorption capacity for each anion. Stoichiometric counterion desorption due to chromate and/or nitrate sorption further confirms that sorption of oxyanions by surfactant‐modified clay minerals was due to surface anion exchange. The selectivity coefficients were higher for chromate to replace bromide than for nitrate to replace bromide for surfactant‐modified kaolinite, but lower when surfactant‐modified illite and smectite were the anion exchangers. The results indicate that surfactant‐modified clay minerals are effective sorbents to remove anionic contaminants from water. However, the types of clay minerals should be correctly selected to maximize the contaminant removal efficiency.
Nitrite and the Two Stages of Nitrification in Nitrogen Polluted Onondaga Lake, New York
Authors: Gelda Rakesh K. , Effler Steven W. , Brooks Carol M. 
Published: July 2010

AbstractNitrite (NO−2) concentrations in the upper waters of N polluted Onondaga Lake, New York, are documented for the April through October interval for a 10‐yr (1989–1998) period. Inputs of NO−2 from a domestic waste treatment facility (METRO) and tributaries (4) to the lake are quantified for four of the years (1991–1994). The NO−2 concentrations measured in Onondaga Lake (e.g., annual maxima in the range 200–1000 mg N m 3) are some of the highest reported for lakes and rivers in the literature. These levels represent severe violations of toxicity standards. Annual average concentrations in the METRO effluent ranged from 412 to 1097 mg N m−3. The METRO load represented >90% of the total external NO−2 load to the lake. A mechanistic mass balance model for NO−2 and NO−3 is developed and applied for the lake to identify occurrences, and quantify the rates, of the first and second stages of nitrification. Nitrite is found to behave in a nearly conservative manner in the upper waters of the lake over the April to July interval. The progressive increases in concentrations over this interval have been largely in response to inputs from METRO. Major deviations from conservative behavior occurred for NO−2 in most years over the July to October interval as a result of the irregular operation of the two stages of the nitrification process. This has been manifested as large and abrupt changes in NO−2 concentration in the July to October interval. Potential factors responsible for the observed dynamics in nitrification and the NO−2 pool are considered.
Plant Community Responses to Disturbance by Mechanized Military Maneuvers
Authors: Milchunas Daniel G. , Schulz Keith A. , Shaw Robert B. 
Published: July 2010

AbstractThe effects of 10 yr of military training exercises on vegetation structure were assessed across plant communities that differed in physiognomy and soil texture at Pinon Canyon Maneuver Site (PCMS), Colorado, after release from previous grazing management. Covariate analyses aided in separating temporal trends due to both release from grazing and imposition of training disturbance from the direct effect of training. The shift in land use had both synergistic and antagonistic impacts on successional trajectories of communities, and on horizontal and vertical structural heterogeneity. Vegetation basal cover declined with increasing intensity of disturbance by tracked vehicles, but release from grazing acts additively in this ecosystem. Litter cover increased following release from grazing, even though it declined with increasing levels of disturbance. Vehicular maneuvering generally reduced woody life forms in tail‐height classes to a greater extent than short‐height classes. Low growing cacti were susceptible to crushing. Species and functional group responses to vehicular disturbance were sometimes dependent on community type. Long‐lived perennials declined, but were replaced by short‐lived perennials in only the shrub‐grassland community. Annuals and exotics did not show relationships with intensity of disturbance, though some weed species increased. Community‐wide species dissimilarity did not show large shifts, and patterns in species diversity or richness were not related to intensity of disturbance. The PCMS appears to be in a transient stage where release from grazing has had as much or more impacts as did the imposition of military training. Fine textured soils may be more susceptible to the cumulative effects of vehicular loads.
Physiological Effects of the Mexico City Atmosphere on Lichen Transplants on Oaks
Authors: Zambrano A. , Nash T. H. , Gries C. 
Published: July 2010

AbstractTwo lichen species, Usnea ceratina Ach. and Everniastrum neocirrhatum (Hale M. Wirth) Hale ex Sipman, were transplanted for 54 d into an oak forest (Quercus rugosa) in the vicinity of Mexico City to assess their ability to survive near a highly polluted urban environment. Net photosynthesis based on dry weight and chlorophyll b decreased respectively ca. 30 and 25% compared with control samples in a less polluted site, ca. 100 km north of Mexico City. There was no interspecific difference in the response of carbon fixation, but E. neocirrhatum was more sensitive to chlorophyll b degradation near Mexico City than U. ceratina. Chlorophyll a was also degradated (ca. 15%) near Mexico City. Changes in total carotenes were mostly dependent on species and time rather than on location. High concurrent levels of ozone and sulfur dioxide in the air are discussed as possible causes of the decline in the lichen photosynthesis and chlorophyll content.
Radiological Impact of Phosphogypsum Applied to Soils under Bahiagrass Pasture
Authors: Alcordo I. S. , Rechcigl J. E. , Roessler C. E. , Littell R. C. 
Published: July 2010

AbstractPhosphogypsum (PG), a by‐product in the manufacture of phosphoric acid, is primarily gypsum. The USEPA regulates the removal of PG from stacks because it contains 226Ra. Measures to quantify the transfer of radioactivity in PG to the agricultural environment are needed. The objective of the study was to collect data needed for assessment of the radiological impacts of PG applied to two Florida soils. Field experiments using 0, 10, and 20 Mg PG ha−1 were conducted for 2 yr at the University of Florida RCREC, Ona, FL. PG‐attributable levels of 226Ra, 210Pb, and 210Po were observed in the top 5‐cm layer of the soils. Surface 222Rn flux increased by 0.067 to 0.078 mBq m−2 s 1 per Mg PG ha−1. Radionuclide concentrations in regrowth forages increased at one site where the first post‐treatment rainfall did not occur until 20 d after PG application. In mature forages, radionuclide levels generally increased with PG in both soils. No effects on radionuclide levels in subsurface water down to 90 cm and only slight effects on gamma radiation and on airborne 222Rn measured 1 m from the ground were noted. The linear regression slope for a radiological parameter normalized with respect to the pertinent radionuclide applied per m2 per Mg PG ha−1 is proposed as the transfer factor (TF) of that radionuclide in PG to the agricultural medium in terms of that parameter. The TF permits the calculation of the potential effect on certain radiological parameters of PCs containing different radionuclide concentrations from the one used in this study.
Long‐Term Monitoring of Soil Gas Fluxes with Closed Chambers Using Automated and Manual Systems
Authors: Scott Albert , Crichton Ian , Ball Bruce C. 
Published: July 2010

AbstractWe describe two gas sample collection techniques, each of which is used in conjunction with custom made automated or manually operated dosed chambers. The automated system allows automatic collection of gas samples for simultaneous analysis of multiple trace gas efflux from soils, permitting long‐term monitoring. Since the manual system is cheaper to produce, it can be replicated more than the automated and used to estimate spatial variability of soil fluxes. The automated chamber covers a soil area of 0.5 m2 and has a motor driven lid that remains operational throughout a range of weather conditions. Both systems use gas‐tight containers of robust metal construction, which give good sample retention, thereby allowing longterm storage and convenience of transport from remote locations. The containers in the automated system are filled by pumping gas from the closed chamber via a multiway rotary valve. Stored samples from both systems are analysed simultaneously for N2O and CO2 using automated injection into laboratory‐based gas chromatographs. The use of both collection systems is illustrated by results from a field experiment on sewage sludge disposal to land where N2O fluxes were high. The automated gas sampling system permitted quantification of the marked temporal variability of concurrent N2O and CO2 fluxes and allowed improved estimation of cumulative fluxes. The automated measurement approach yielded higher estimates of cumulative flux because integration of manual point‐in‐time observations missed a number of transient high‐flux events.
The Influence of Nitrilotriacetate on Heavy Metal Uptake of Lettuce and Ryegrass
Authors: Kulli B. , Balmer M. , Krebs R. , Lothenbach B. , Geiger G. , Schulin R. 
Published: July 2010

AbstractMetal uptake and removal from the soil by plants may be a useful measure to remediate contaminated soils. These processes can be enhanced by adding metal chelators to soil. We investigated the effect of nitrilotriacetate (NTA) and urea on the uptake of Cd, Cu, and Zn by lettuce (Lactuca sativa L. cv. Orion) and Italian ryegrass (Lolium perenne L. cv. Bastion) in pot experiments. Nitric acid‐extractable heavy metal concentrations in the contaminated soil were 2 mg Cd, 530 mg Cu, and 700 mg Zn kg−1. Three NTA treatments (0.5, 1.8, and 5.3 mol m−2) were compared with two urea treatments (0.25 and 0.9 mol m−2), and a control. Nitrilotriacetate and urea increased the NaNO3‐extractable soil concentrations of the three metals. At the highest NTA dose, metal concentrations in the aboveground plant biomass was 4 to 24 times greater than in the control plants. While NTA increased plant metal concentrations, it reduced plant matter production. At lower doses, this effect was small. At the highest NTA dose, plant growth was almost completely inhibited. Severe visual symptoms indicated metal toxicity as the likely cause. The urea treatments generally increased the plant matter production. Total metal uptake was in general larger at the lowest or at the intermediate NTA dose than at the highest doses. Little additional total metal uptake was achieved with NTA treatments than with urea. Compared with the controls, neither NTA nor urea enhanced total uptake under the given conditions by more than threefold.