bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using beryllium‐7 to monitor the relative proportions of interrill and rill erosion from loessal soil slopes in a single rainfall event
Authors: Liu Gang , Yang Ming Yi , Warrington D.N. , Liu Pu Ling , Tian Jun Liang 
Published: August 2010

AbstractQuantifying the relative proportions of soil losses due to interrill and rill erosion processes during erosion events is an important factor in predicting total soil losses and sediment transport and deposition. Beryllium‐7 (7Be) can provide a convenient way to trace sediment movement over short timescales providing information that can potentially be applied to longer‐term, larger‐scale erosion processes. We used simulated rainstorms to generate soil erosion from two experimental plots (5 m × 4 m; 25° slope) containing a bare, hand‐cultivated loessal soil, and measured 7Be activities to identify the erosion processes contributing to eroded material movement and/or deposition in a flat area at the foot of the slope. Based on the mass balance of 7Be detected in the eroded soil source and in the sediments, the proportions of material from interrill and rill erosion processes were estimated in the total soil losses, the deposited sediments in the flat area, and in the suspended sediments discharged from the plots. The proportion of interrill eroded material in the discharged sediment decreased over time as that of rill eroded material increased. The amount of deposited material was greatly affected by overland flow rates. The estimated amounts of rill eroded material calculated using 7Be activities were in good agreement with those based on physical measurements of total plot rill volumes. Although time lags of 45 and 11 minutes existed between detection of sediment being removed by rill erosion, based on 7Be activities, and observed rill initiation times, our results suggest that the use of 7Be tracer has the potential to accurately quantify the processes of erosion from bare, loessal cultivated slopes and of deposition in flatter, downslope areas that occur in single rainfall events. Such measurements could be applied to estimate longer‐term erosion occurring over larger areas possessing similar landforms. Copyright © 2010 John Wiley & Sons, Ltd.
The effects of wildfires on the magnetic properties of soils in the Everglades
Authors: Clement Bradford M. , Javier Jose , Sah Jay P. , Ross Michael S. 
Published: August 2010

AbstractWe present results of a rock‐magnetic study of soils that were affected by wildfires that burned portions of the Everglades in the Spring of 2008. Soils at sites that were extensively burned exhibit a pronounced surface magnetic enhancement effect with magnetizations of surface samples up to 16 times greater than that observed at depth (>7 cm) at these sites. The increase in magnetization results from an increased abundance of a low‐coercivity phase (maghemite) that occurs at the expense of the abundance of a high‐coercivity phase (goethite). These results indicate that fire‐induced heating caused goethite in the surface soils to convert into a more magnetic, low‐coercivity phase, such as maghemite. Goethite is an excellent adsorber of phosphorus, and therefore we hypothesize that the destruction of goethite as a result of burning may have important implications for phosphorus cycling in the Everglades ecosystem. Copyright © 2010 John Wiley & Sons, Ltd.
High resolution transmission electron microscopy evaluation of silica glaze reveals new textures
Authors: Langworthy K. A. , Krinsley D. H. , Dorn R. I. 
Published: August 2010

AbstractWe present the first nanoscale investigation of silica glaze. High resolution transmission electron microscopy of a rock coating from the Ashikule Basin, Tibetan Plateau, reveals the presence of spheroids composed predominantly of silicon and oxygen with diameters ranging from 20 nm to 70 nm. While silica glaze spheroids co‐exist with manganese‐rich rock varnish in the same sample, the different rock coatings are texturally and physically distinct at the nanoscale. These observations are consistent with a model of silica glaze formation starting with soluble aluminum‐silicon (Al‐Si) complexes [Al(OSi(OH)3)2+], mobilized with gentle wetting events such as dew or frost. The transition between complete and partial wetting on silica surfaces rests at about 20–70 nm for liquid droplets. Upon crossing this transition, a metastable wetting film would be ruptured, initiating formation of silica glaze through spheroid deposition. Copyright © 2010 John Wiley & Sons, Ltd.
Relative importance of dust inputs and aquatic biological production as sources of lake sediments in an oligotrophic lake in a semi‐arid area
Authors: Oseguera Luis A. , Alcocer Javier , Vilaclara Gloria 
Published: August 2010

AbstractThe dustfall (DF) and mass sedimentation rate (MSR) in Lake Alchichica, Central Mexico, were studied from June 2006 to June 2008. DF ranged between 0·11–0·93 g m−2 d−1 in the warm and rainy season and 0·54–1·21 g m−2 d−1 in the cold and dry season. MSR varied from 0·52–2·40 g m−2 d−1 in the stratification season to 1·14–5·07 g m−2 d−1 in the circulation season. The timing of the highest fluxes of DF and MSR is most likely a product of several factors coinciding during the cold and dry season: (a) availability of dust sources and the presence of strong winds (>7·5 m s−1) in the DF case, and (b) the circulation period of the lake and the availability of nutrients in the MSR case. As expected, the DF in Alchichica was high and similar to that found in other arid and semi‐arid areas. However, the MSR was higher than that reported for other oligotrophic lakes. Particles captured in the aerial traps consisted mainly of detrital minerals; in contrast, particles found in the water traps were mostly biogenic and, to a lesser extent, detrital minerals. The MSR was one to seven times higher than the DF. In spite of the oligotrophic status of Lake Alchichica, the large size of the settled phytoplankton (autochthonous, waterborne) is what leads to the high MSR, which surpasses the DF (allochthonous, airborne) derived from whirlwinds originating in easily eroded terrains that are characteristic of arid/semi‐arid areas. Our results indicate that caution must be taken in considering that the DF amount measured through DF collectors located at the lake shore does actually represent the DF entering into the lake. Copyright © 2010 John Wiley & Sons, Ltd.
Distance, time and scale in soil erosion processes
Authors: Kirkby M. J. 
Published: August 2010

AbstractThis commentary brings together, as a virtual Special Issue, a number of recent papers in Earth Surface Processes and Landforms that are all related to issues of scale in soil erosion. Empirical concepts that were developed in the 1940s are now in need of re‐thinking, and papers are increasingly exploring, through modelling and measurement, appropriate ways to recognize the mechanisms that connect processes across time and space scales. Issues include a more nuanced approach to selective transportation, responses to variability in surface and sub‐surface conditions and the need to analyse measurements in ways that can be transferred between sites and storms. Copyright © 2010 John Wiley & Sons, Ltd.
Effects from filtration, capping agents, and presence/absence of food on the toxicity of silver nanoparticles to Daphnia magna
Authors: Allen H. Joel , Impellitteri Christopher A. , Macke Dana A. , Heckman J. Lee , Poynton Helen C. , Lazorchak James M. , Govindaswamy Shekar , Roose Deborah L. , Nadagouda Mallikarjuna N. 
Published: August 2010

Abstract
Relatively little is known about the behavior and toxicity of nanoparticles in the environment. Objectives of work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvantages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a silver nitrate solution and AgNPs suspensions including commercially available AgNPs (uncoated and coated), and laboratory-synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were analyzed for silver concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicities of filtered (100 nm) versus unfiltered suspensions were compared. Additionally, effects from addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water, which were then diluted and used straight or after filtration with 100-nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma–optical emission spectroscopy or graphite furnace–atomic absorption spectroscopy. Dose–response curves were generated and median lethal concentration (LC50) values calculated. The LC50 values for the unfiltered particles were (in µg/L): 1.1 ± 0.1-AgNO3; 1.0 ± 0.1-coffee coated; 1.1 ± 0.2-citrate coated; 16.7 ± 2.4 Sigma Aldrich Ag-nanoparticles (SA) uncoated; 31.5 ± 8.1 SA coated. LC50 values for the filtered particles were (in µg/L): 0.7 ± 0.1-AgNO3; 1.4 ± 0.1-SA uncoated; 4.4 ± 1.4-SA coated. The LC50 resulting from the addition of food was 176.4 ± 25.5-SA coated. Recommendations presented in this study include AgNP handling methods, effects from sample preparation, and advantages/disadvantages of different nanoparticle characterization techniques. Environ. Toxicol. Chem. 2010;29:2742–2750. © 2010 SETAC
Neutral and phenolic brominated organic compounds of natural and anthropogenic origin in northeast Atlantic Greenland shark (Somniosus microcephalus)
Authors: Strid Anna , Athanassiadis Ioannis , Athanasiadou Maria , Svavarsson Jörundur , Päpke Olaf , Bergman Åke 
Published: August 2010

Abstract
In the present study, muscle and liver tissue from 10 female Greenland sharks (Somniosus microcephalus) collected in Icelandic waters were analyzed for neutral and phenolic brominated organic compounds, including polybrominated diphenyl ethers (PBDEs) and the structurally related methoxylated (MeO) and hydroxylated (OH) PBDEs. Hydroxylated PBDEs exist both as natural products and as metabolites of the anthropogenic PBDEs, whereas MeO-PBDEs appear to exclusively be of natural origin. Other compounds examined were 2′,6-dimethoxy-2,3′,4,5′-tetrabromodiphenyl ether (2′,6-diMeO-BDE68), 2,2′-dimethoxy-3,3′,5,5′-tetrabromobiphenyl (2,2′-diMeO-BB80), 2,4,6-tribromoanisol (2,4,6-TBA) and 2,4,6-tribromophenol, all of natural origin, although 2,4,6-TBA and its phenolic counterpart may also be of anthropogenic origin. The major brominated organic compound was 6-MeO-BDE47, and ΣMeO-PBDE ranged from 49 to 210 ng/g fat in muscle and from 55 to 200 ng/g fat in liver tissue. Total concentrations of PBDEs were lower than ΣMeO-PBDE, in all but one sample, ranging between 7.3 to 190 and 9.9 to 200 ng/g fat in muscle and liver, respectively, and major congeners were BDE-47, BDE-99, and BDE-100. Polybrominated diphenyl ethers were analyzed using both high- and low-resolution mass spectrometry (MS) as a quality assurance, and the results from this comparison were acceptable. In accordance with previous work on Greenland sharks, no size/age-related accumulation was observed. Differences seen in concentrations were instead assumed to be a reflection of different feeding habits among the individuals. Phenolic compounds were only formed/retained in trace amounts in the Greenland shark. Among the phenolic compounds studied were 6-OH-BDE47, 2′-OH-BDE68, and 2,4,6-tribromophenol, all detected in liver and the latter two in muscle. Environ. Toxicol. Chem. 2010;29:2653–2659. © 2010 SETAC
Growth, abnormalities, and mortality of tadpoles of American toad exposed to combinations of malathion and nitrate
Authors: Krishnamurthy Sannanegunda V. , Smith Geoffrey R. 
Published: August 2010

AbstractAmerican toad tadpoles (Bufo americanus) were exposed to malathion and nitrate in a fully factorial experiment that crossed four concentrations of malathion ranging between 0 and 1,000 µg malathion/L, and five concentrations of nitrate ranging from 0 to16 mg NO3-N/L to identify single and interactive effects. In this 21-d experiment, we recorded tadpole length, mass, survivorship, and frequencies of diamond-shaped and stiff-tail abnormalities. Malathion increased frequency of diamond-shaped and stiff-tail abnormalities, and negatively affected survivorship, but did not affect tadpole size. Nitrate did not affect survivorship but did have sublethal effects, including effects on tadpole length and the frequency of both abnormalities. The interaction of malathion and nitrate has no effect on survivorship or tadpole size but did affect the frequency of abnormalities, with nitrate reducing malathion's effect. Results of the present study suggest that at the environmentally realistic concentrations used in our experiment, malathion has both lethal and sublethal effects, but nitrate had only sublethal effects on American toad tadpoles. The combination of malathion and nitrate had limited effects at the tested concentrations under laboratory conditions. However, the effect of the combined treatments on the frequency of tadpole developmental abnormalities suggests that such interactions may play a role under field conditions, in which pesticide and nitrate fertilizers are typically applied simultaneously. Environ. Toxicol. Chem. 2010;29:2777–2782. © 2010 SETAC
Assessing contaminated sediments in the context of multiple stressors
Authors: Burton G. Allen , Johnston Emma L. 
Published: August 2010

AbstractSediments have a major role in ecosystem functioning but can also act as physical or chemical stressors. Anthropogenic activities may change the chemical constituency of sediments and the rate, frequency, and extent of sediment transport, deposition, and resuspension. The importance of sediments as stressors will depend on site ecosystem attributes and the magnitude and preponderance of co-occurring stressors. Contaminants are usually of greater ecological consequence in human-modified, depositional environments, where other anthropogenic stressors often co-occur. Risk assessments and restoration strategies should better consider the role of chemical contamination in the context of multiple stressors. There have been numerous advances in the temporal and spatial characterization of stressor exposures and quantification of biological responses. Contaminated sediments causing biological impairment tend to be patchy, whereas more pervasive anthropogenic stressors, such as alterations to habitat and flow, physical disturbance, and nutrient addition, may drive large-scale ecosystem responses. A systematic assessment of relevant ecosystem attributes and reference conditions can assist in understanding the importance of sediments in the context of other stressors. Experimental manipulations then allow for the controlled study of dominant stressors and the establishment of causal links. This approach will result in more effective management of watersheds and waterways. Environ. Toxicol. Chem. 2010;29:2625–2643. © 2010 SETAC
Evaluation of reduced sediment volume procedures for acute toxicity tests using the estuarine amphipodLeptocheirus plumulosus
Authors: Stanley Jacob K. , Kennedy Alan J. , Farrar J. Daniel , Mount David R. , Steevens Jeffery A. 
Published: August 2010

AbstractThe volume of sediment required to perform a sediment toxicity bioassay is a major driver of the overall cost associated with that bioassay. Sediment volume affects bioassay cost because of sediment collection, transportation, storage, and disposal costs as well as labor costs associated with organism recovery at the conclusion of the exposure. The objective of the current study was to evaluate reduced sediment volume versions of the standard U.S. Environmental Protection Agency (U.S. EPA) 10-d acute Leptocheirus plumulosus method that uses a beaker size of 1,000 ml and 20 organisms. The test design used evaluated the effects of beaker size (250 and 100 ml) and associated sediment volume (75 and 30 ml, respectively) as well as organism loading density (10 and 20 organisms) on test endpoint responsiveness relative to the standard 10-d test method. These comparisons were completed with three different types of contaminated sediments: a field-collected polycyclic aromatic hydrocarbon (PAH)-contaminated sediment, a lead-spiked control sediment, and a control sediment spiked with mineral oil. Assessment criteria included test endpoint sensitivity, endpoint consistency, statistical power, water quality, and logistical assessments. Results indicate that the current U.S. EPA method is preferable to the reduced sediment volume methods we assessed, but that a 250-ml beaker/10 organism experimental design is of comparable utility and may be advantageous when reduced sediment volumes are desirable because of high contaminant (spiking studies) or sediment disposal costs. In addition, the results of the current study provide toxicity reference values for PAHs, lead, and an oil surrogate for petroleum hydrocarbons. Environ. Toxicol. Chem. 2010;29:2769–2776. © 2010 SETAC
Selecting an ignition criterion methodology for use in a radiative fire spread submodel
Authors: Baker Gregory B. , Spearpoint Michael J. , Fleischmann Charles M. , Wade Colleen A. 
Published: August 2010

AbstractResearch is ongoing to increase the functionality of the fire zone modeling software BRANZFIRE, by converting it from a deterministic to a probabilistic model. One component of this work is the development of a radiative fire spread submodel for which a suitable ignition criterion method is needed. This paper provides details of that ignition criterion procedure and its implementation into the submodel.A list of requirements that the ignition methodology had to satisfy was established. Of the many different piloted ignition models available, the Flux–Time Product technique, and its associated ignition criterion, was selected to be incorporated into the fire spread submodel. This method provides a practical engineering approximation of when a secondary fuel item that is subjected to incident radiation will ignite that is commensurate with the accuracy of the overall model.Primarily to demonstrate the use of the technique in the submodel, a series of ignition experiments were conducted on a single example of upholstered furniture using the Cone Calorimeter apparatus, with specimens tested in both the horizontal and vertical orientation, under piloted and auto ignition conditions. The experimental incident radiation and time‐to‐ignition data, for the piloted ignition mode, was analyzed using a modified Flux–Time Product correlation procedure.To deal with the auto ignition mode, an empirical approximation, based on the modified Flux–Time Product procedure, is proposed. Data for use in the submodel was therefore also derived for the auto ignition mode, based on an experimental determination of the minimum ignition flux. Copyright © 2010 John Wiley & Sons, Ltd.
Adaptive methods for multi‐material ALE hydrodynamics
Authors: Rider W. J. , Love E. , Wong M. K. , Strack O. E. , Petney S. V. , Labreche D. A. 
Published: August 2010

AbstractArbitrary Lagrangian–Eulerian (ALE) methods are commonly used for challenging problems in hydrodynamics. Among the most challenging matters are the approximations in the presence of multiple materials. The ALE code ALEGRA has used a constant volume method for computing the impact of multiple materials on both the Lagrangian step and the remap step of the method. Here, we describe modifications to these methods that provide greater modeling fidelity and better numerical and computational performance. In the Lagrangian step, the effects of differences in material response were not included in the constant volume method, but have been included in the new method. The new methodology can produce unstable results unless the changes in the variable states are carefully controlled. Both the stability analysis and the control of the instability are described. In the standard (Van Leer) method for the remap, the numerical approximation did not account for the presence of a material interface directly. The new methodology uses different, more stable and more dissipative numerical approximations in and near material interfaces. In addition, the standard numerical method, which is second‐order accurate, has been replaced by a more accurate method, which is third‐order accurate in one dimension. Published in 2010 by John Wiley & Sons, Ltd.
USING CONSTRUCTED WETLANDS TO IMPROVE DRAINAGE WATER QUALITY FROM HYDROPONICS FARMS
Authors: Abbassi Bassim , Al‐Zboon Kamel , Radaideh Jamal , Wahbeh Alaa' 
Published: August 2010

ABSTRACTIn this work, two types of pilot constructed wetlands were used to treat drainage water from the hydroponics farm in the Jordan Valley. Zeotuff was used as wetland filtering media. The wetlands were planted with giant reeds (Arundo donax L.). The performance of the wetland systems under varying hydraulic retention times (HRT) was investigated in terms of BOD, COD, NO3, PO4, cations, anions, TSS, salinity and water conservation. It has been found that the vertical flow wetland was able to reduce the biochemical oxygen demand (BOD5) concentration by more than 93% at an HRT of 7 days, where the BOD5 removal was about 89% by the horizontal flow wetland at the same HRT. The percentage removal of total suspended solids (TSS) was found to be 98 and 94% by the vertical and horizontal flow wetlands, respectively. Nutrient content (nitrate and phosphate) was reduced in both wetlands at lower HRTs by more than 77%. Both wetlands obtained high efficiency in chemical oxygen demand (COD) removal as the quality of effluent water was found to comply closely with the Jordanian Irrigation Guidelines. The wetlands were able to greatly reduce the cations and anions contained in the influent water. The vertical flow wetland system exhibited more efficiency as a treatment facility than the horizontal flow wetland system. Copyright © 2010 John Wiley & Sons, Ltd.
OPTIMIZING SUBSURFACE DRAINAGE PRACTICES IN IRRIGATED AGRICULTURE IN THE SEMI‐ARID AND ARID REGIONS: EXPERIENCES FROM EGYPT, INDIA AND PAKISTAN
Authors: Ritzema Henk , Schultz Bart 
Published: August 2010

ABSTRACTIn this paper, the role of subsurface drainage in irrigated agriculture in semi‐arid and arid regions is discussed based on experiences obtained in Egypt, India and Pakistan. Agriculture in these countries is predominantly practiced by small, marginal farmers with landholdings of often less than one hectare. In general, they do not have the means to pay for the investments in irrigation and drainage themselves. Consequently, most irrigation and drainage projects are funded by the (local) governments. Shallow horizontal pipe drainage systems have proved to be a technically feasible and cost‐effective tool to combat the twin problem of waterlogging and salinity. Their large scale implementation is, however, hampered by a number of institutional and socio‐economic reasons. The paper discusses why subsurface drainage is needed to safeguard investments in irrigated agriculture and to conserve land resources, as well as what the challenges are to make subsurface drainage work. Copyright © 2010 John Wiley & Sons, Ltd.