bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequential Fractionation of Copper, Lead, Cadmium and Zinc in Soils from or near Doñana National Park
Authors: Ramos L. , Hernandez L. M. , Gonzalez M. J. 
Published: July 2010

AbstractA knowledge of the total amount of trace metals is not enough to assess the environmental impact of polluted soils. For this reason, the determination of metal species in solution is important to evaluate their behavior in the environment and their mobilization capacity. Soils contaminated by Cu, Pb, Cd, and Zn found at Doñana National Park (Spain) were examined for total content. Sequential extraction schemes were used to determine the degree of pollution and to partition the trace elements in soils. The three areas studied (marshes, stabilized sand, and mine) have different contamination levels. The northern‐most marshes of Doñana National Park have the highest total levels of the four metals due to the influence of a mine located 40 km away. The stabilized sand was not polluted by the metals studied. The bioavailable fraction of Cd represents more than 50% of the total Cd found in soils, and this percentage is much greater than that of the other elements examined. Most of the Cu was present in the organic fraction, with only small amounts being associated with the crystalline Fe‐oxide fraction. Lead and Zn were associated mainly with the crystalline Fe‐oxide fraction, but the amount of Zn associated with the carbonates and amorphous Fe‐oxide fractions was also significant. The total amount of Cu, Pb, Cd, and Zn in the soils and their distribution in the five fractions depended on total metal contents, soil type, and soil properties (i.e., pH and percentage of sand, clay, organic matter, and carbonates). Mobility of soil metals were Cd > Zn > Pb > Cu.
Ultraviolet‐B Radiation and Ozone Effects on Growth, Yield, and Photosynthesis of Soybean
Authors: Miller J. E. , Booker F. L. , Fiscus E. L. , Heagle A. S. , Pursley W. A. , Vozzo S. F. , Heck W. W. 
Published: July 2010

AbstractThe projected increase in solar ultraviolet‐B (UV‐B) radiation due to depletion of stratospheric ozone (O3) has caused concern regarding possible UV‐B damage to crops. At the same time, tropospheric O3 is projected to remain at concentrations that are known to damage crops. Since these two stressors may co‐occur, experiments were performed to determine their separate and joint effects on crop growth, yield, and photosynthesis. Open‐top chambers, equipped with filtered UV‐B lamp systems, were used in 3 yr of field studies to treat soybean [Glycine max (L.) Merr.; ‘Coker 6955’, ‘Essex’, and ‘S 53‐34’] with supplemental UV‐B radiation and/or O3 from emergence through physiological maturity. Treatment levels of biologically effective UV‐B radiation (UV‐BBE) simulated the increase in ground level UV‐B for stratospheric O3 depletion up to 37% (approximately a doubling of ambient UV‐BBE). Ozone treatment concentrations ranged from 14 to 83 nL L−1 (seasonal mean 12 h d−1 concentrations). Ultraviolet‐B radiation did not affect soybean seed yield in any of the 3 yr of the study. In 1 yr, UV‐B affected pod and seed number and pod weight, but the treatment means were not consistently related to the UV‐B dose. No O3 × UV‐B interactions were found for any yield component at final harvest. Biweekly harvests of Essex during the growing season did not reveal any persistent effects of increased UV‐B radiation on growth. Net carbon exchange rate (NCER), stomatal conductance, and transpiration of Essex soybean leaves were not suppressed by supplemental UV‐B radiation. On the other hand, O3 treatment consistently induced visible injury, suppressed NCER and water use efficiency, accelerated reproductive development, and suppressed growth and yield. It is concluded that tropospheric O3 poses a greater threat to soybean production than projected levels of UV‐B radiation.
Potential for Bioremediation of High Nitrate Irrigation Water Via Denitrification
Authors: Weier K. L. , Doran J. W. , Mosier A. R. , Power J. F. , Peterson T. A. 
Published: July 2010

AbstractNitrogen fertilizer application to irrigated corn (Zea mays L.) can result in N leaching from the crop rooting zone into groundwater. Microbial denitrification, with ethanol as an energy source, was evaluated for prevention of groundwater contamination under irrigated corn in Nebraska where irrigation water NO−3‐N levels can exceed 30 mg L−1. A field study was conducted on a Hord silt loam (Pachic Haplustoll) in central Nebraska by installing plastic (PVC) cylinders (28.7‐cm diam. by 1.8 m long) in soil to a depth of 1.2 m and irrigating with 17.1 cm of water containing 30 mg L−1 isotopically enriched (76.6 atom% 15N) KNO3‐N equivalent to 51.8 kg N ha−1. Soil remediation treatment included addition of 10 mL ethanol (644 kg C ha−1) to three of six cylinders. Gas samples taken every 6 h for 4 d from the soil surface and soil profile indicated that ethanol addition stimulated microbial respiration and denitrification. Cumulative loss of gaseous N from the soil surface over this period was 12.7 kg N ha−1 or 24.5% of the added 15N‐NO3; an additional 27 kg N ha−1 NO3 was lost from the ethanol‐amended soil profile. In the laboratory, intact soil cores taken at five intervals to a 132‐cm soil depth adjacent to field cylinders were brought to 90% WFPS (water‐filled pore space) by applying treatments of ethanol (19.8 kg C ha−1) and NO−3 (0.88 kg NO−3‐N ha−1) and incubated at 25 °C, with 100 mL L−1 C2H2, for 7 d during which time headspace gas samples were analyzed for N2O and CO2. Soil respiration and denitrification increased with ethanol addition except in surface soil where C availability was not limiting. We conclude that ethanol addition to high NO−3 irrigation water may remediate groundwater NO−3 contamination.
Sugarcane Production Impact on Nitrogen and Phosphorus in Drainage Water from an Everglades Histosol
Authors: Coale F. J. , Izuno F. T. , Bottcher A. B. 
Published: July 2010

AbstractThe Everglades Agricultural Area (EAA) in southern Florida is a 280 000‐ha tract of land that has come under scrutiny by environmental, agricultural industry, and government water management groups that are concerned with the impact of nutrient‐enriched drainage water on the ecology of adjoining bodies of water and wetlands. Sugarcane (Saccharum sp.) is grown on 155 000 ha or 78% of the cultivated organic soils in the EAA. The objectives of this study were to determine the N and P concentrations and off‐field loads in drainage water from sugarcane and fallow fields. Sugarcane was planted in four of eight hydraulically independent and similar field plots. Four plots were maintained fallow. Drainage water volume, and total nitrogen (TN), total dissolved phosphorus (TDP), and total phosphorus (TP) concentrations were monitored during 12 drainage events during two crop seasons. For two drainage events, TN concentrations were higher in drainage water from fallow plots that in drainage water from sugarcane plots and it was speculated that crop uptake of mineralized soil N may have contributed to the reductions during these events. Analysis of the mean for the 12 drainage events indicated no overall differences in TN off‐field loads between sugarcane and fallow plots. Further, no significant differences were found in TDP or TP concentration in drainage water from sugarcane and fallow plots during any of the drainage events monitored. It was concluded that, due to the large quantity of soil N and P mineralized and due to crop N and P uptake, the impact of sugarcane production on drainage water N and P concentrations was minimal.
Frequency of MUG Negative Escherichia coli in Kentucky Groundwater Samples
Authors: Coyne Mark S. , Schuler Jan C. 
Published: July 2010

AbstractMUG negative Escherichia coli are a small fraction (2.5%) of the total E. coli in Kentucky groundwater samples. It is unlikely that they alone will cause a significant potential to underestimate fecal contamination using MUG as the primary criterion for that assessment. An unresolved question is how effectively MUG‐based, defined‐substrate tests address false negative water samples containing MUG positive E. coli.
Impact of Long‐Term Land Application of Broiler Litter on Environmentally Related Soil Properties
Authors: Kingery W.L. , Wood C.W. , Delaney D.P. , Williams J.C. , Mullins G.L. 
Published: July 2010

AbstractThe largest portion of Alabama's rapidly growing poultry industry is geographically concentrated in the Sand Mountain region of northern Alabama. The result is that large amounts of waste are applied to relatively small areas of agricultural soils. A study was conducted to determine the effects of long‐term broiler waste (litter) application on environmentally related soil conditions in the region. The region has an average annual rainfall of 1325 mm, which is evenly distributed throughout the year, a thermic temperature regime, and soils in the region are of the Ultisol order. In each of four major broiler‐producing counties, three pairs of sites consisting of long‐term (15–28 yr) littered and nonlittered fields on matching soil series and maintained under perennial tall fescue (Festuca arundinacea Schreb.) were sampled. Soil cores were taken to 3 m or lithic contact and depth‐incremented samples (0–15, 15–30, and each subsequent 30‐cm interval) were analyzed for organic C, total N, NO3‐N, pH, electrical conductivity, and acid‐extractable P, K, Ca, Mg, Cu, and Zn. Litter application increased organic C and total N to depths of 15 and 30 cm, respectively, as compared with nonlittered soils, whereas pH was 0.5 units higher to a depth of 60 cm under littered soils. Significant accumulation of NO3‐N was found in littered soils to or near bedrock. Extractable P concentrations in littered soils were more than six times greater than in nonlittered soils to a depth of 60 cm. Elevated levels of extractable K, Ca, and Mg to depths greater than 60 cm also were found as a result of long‐term litter use. Extractable Cu and Zn had accumulated in littered soils to a depth of 45 cm. These findings indicate that long‐term land application of broiler litter, at present rates, has altered soil chemical conditions and has created a potential for adverse environmental impacts in the Sand Mountain region of Alabama.
Adsorption of Dissolved Organic Carbon Extracted from Sewage Sludge on Montmorillonite and Kaolinite in the Presence of Metal Ions
Authors: Baham John , Sposito Garrison 
Published: July 2010

AbstractThe adsorption of dissolved organic carbon extracted from sewage sludge (SSDOC) and its complexes with Cu, Pb, and Cd by montmorillonite and kaolinite was measured at 283, 298, and 308 K. Experiments were conducted at 2 g L−3 clay suspension concentration in an ionic background of 50 mM NaClO4. Sufficient metal ion concentrations were present to saturate the clays (92 and 5 cmol(c) kg−1 for montmorillonite and kaolinite, respectively). The pH value of the suspensions was adjusted to 5.5 prior to initiation of the adsorption experiments. Kinetic studies conducted under aseptic conditions indicated that within 2 h the adsorption of the SSDOC by the clays reached an equilibrium value. Adsorption of SSDOC was found to be reversible with respect to small changes in the concentration of the adsorbate thus meeting the criteria for thermodynamic equilibrium. Rapid adsorption of the SSDOC suggests that adsorption was restricted to the external surfaces of the layer silicates. Statistical analysis of the data showed that all of the isotherms were described by a linear isotherm model. The average isosteric heat of adsorption () was estimated to be 0 ± 2 kJ mol−1 SSDOC, within experimental error, for each of the clay‐metal combinations. The low values for suggests that adsorption of SSDOC by montmorillonite and kaolinite is the result of an increase in the configurational entropy of the clay‐metal‐SSDOC system. Pooled adsorption data across temperatures yielded a single regression line for each clay‐metal‐SSDOC system with the following order of slopes and calculated average free energy of adsorption (): Pb > Cu > Cd. The observed order of the values for follow the same trend for the formation constants of metal humic complexes. This observation suggests that the favorable increase in is the result of changes in the conformation of the SSDOC making adsorption more favorable. When the value for was computed on the basis of external clay surface area the differences between the two clays decreased markedly, suggesting that adsorption was restricted to the external surfaces of the minerals.
Long‐Term Development of Element Fluxes with Bulk Precipitation and Throughfall in Two German Forests
Authors: Matzner E. , Meiwes K. J. 
Published: July 2010

AbstractLong‐term monitoring of element fluxes with bulk precipitation and throughfall in two forest ecosystems of the German Soiling area revealed substantial changes in the chemical climate of these ecosystems. From 1969 to 1990, fluxes of NO3 and NH3 in throughfall increased by 40 to 60%. In contrast, SO4, H+, and Ca fluxes decreased by 30 to 60%. The changes of the element fluxes correspond to the development of emission rates in Germany for dust, SO2, and NO2.
Nonisothermal Sorption Gaseous Exchange in a Synthetic Soil
Authors: Goldman S. , Minkin L.M. 
Published: July 2010

AbstractNonisothermal sorption on soil surfaces is involved in the exchange of gases between soils and the atmosphere. This process is considered in context of soil pore‐size distribution. We found that the gas flux caused by nonisothermal sorption can be significant and can exceed the gas fluxes induced by other physical mechanisms of soil‐atmosphere exchange. We investigated the influence of fluctuations of soil temperature on the amount of gas sorbed to soil. For a given soil mass and for a given primary atmospheric gas, the ratio between the moles of gas sorbed or desorbed on a soil surface due to one Kelvin change of soil temperature and the moles of gas initially adsorbed ranges from 0.016 to 0.054 K−1. This temperature dependence, in turn, leads to a significant change of gas concentration in porous media, especially for dry and fine‐structured soils and clays. Significant gas fluxes can result. For an upper soil layer with a specific surface area of 2 × 104 m2 kg−1, the CO2 flux induced by nonisothermal sorption equals 8.3 × 10−4 kg m−2 s−1 when the soil temperature changes 1 K h−1 . These sorption processes are considered for soils having different pore‐size distributions. In certain fine‐structured soils, the number of sorbed molecules in a given soil mass is similar to the number of nonsorbed (mobile) molecules in the porous volume, particularly for gases with enthalpy of adsorption greater than 20 000 J mol−1 K−1. A new type of function is offered for describing pore diameter distribution. This function can be fitted easily to experimental data for many types of soil matrices, and it is also convenient for statistical moment analysis. This concept has been applied to the matrices of Walla‐Walla (coarse, silty, mixed, mesic Typic Haploxerolls) and Bashaw soils (very fine, montmorillonitic, mesic Typic Pelloxererts) (Oregon).
Sulfate Sorption in Soils under Acid Deposition: Comparison of Two Modeling Approaches
Authors: Prenzel Jürgen 
Published: July 2010

AbstractSoil acidification under the impact of acid deposition is often modeled by adsorption isotherms. The assumption of solubility equilibria for basic Al sulfates is an alternative modeling approach. Similarities and differences between both concepts are discussed. A simple solubility equilibrium model is defined and used to demonstrate that the second model can explain results that are well described by typical adsorption isotherms. The same model can also explain a pH dependency of adsorption isotherms that has been widely reported. In the application to assumed soil acidification scenarios, predictions are presented that could not be described by an adsorption isotherm approach.
Quartz Vein Impact on Hydraulic Conductivity and Solute Transport through Quartz‐Phyllite Saprolite
Authors: Williams J. P. , Vepraskas M. J. , Hoover M. T. 
Published: July 2010

AbstractSaprolite cannot be used for on‐site wastewater disposal in North Carolina if it has quartz veins within 60 cm (2 ft) of the septic trench bottom, because it is believed such features could transmit raw sewage quickly to groundwater. A quartz phyllite saprolite was sampled to compare the saturated and unsaturated hydraulic conductivities between samples with and without quartz veins. The fine sandy loam saprolite had veins that were approximately 0.8 cm wide and comprised 0.2 cm2/cm2 of the sample's cross‐sectional area. The mean saturated hydraulic conductivity values of 32 undisturbed cores with veins and 27 cores without veins were not significantly different (α = 0.10) and the geometric mean for a combined population was 0.85 cm/h. Unsaturated hydraulic conductivities for a soil water pressure head of −30 cm were also not significantly different between the two populations. Dye studies confirmed that water flowed both along the vein but also through the saprolite matrix. Examination of thin sections showed that pores within the vein were coated or plugged with Fe‐Mn oxides that restricted the water movement through the vein. It was computed that a noninteracting solute would travel 60 cm in the vertical direction in 33 h when the saprolite was saturated, and in 88 h when the soil water pressure head was −30 cm. These results suggested the quartz vein would not transmit raw sewage fast enough to contaminate groundwater at the site.
Iron Nutrition Influence on Cadmium Accumulation by Arabidopsis thaliana (L.) Heynh.
Authors: Rodecap Kent D. , Tingey David T. , Lee E. Henry 
Published: July 2010

AbstractGreenhouse experiments were conducted to determine whether Arabidopsis thaliana (L.) Heynh., a putative Fe‐efficient species, accumulated higher concentrations of Cd from a sparingly soluble Cd source (cadmium dihydrogen phosphate) when growing in Fe‐deficient rather than in Fe‐sufficient conditions. The Arabidopsis plants, which were grown in double‐container, vermiculite‐hydroponic plot culture systems and were provided with nutrient solution containing either sufficient (89.5 µM) or deficient (0 µM) Fe supplied as the diethylene triamine pentacetate chelate, were exposed to four levels of Cd (nominally 0, 0.45, 0.89, or 1.78 mmol kg−1 vermiculite). At each substrate Cd level, rosette Cd concentrations were similar at both Fe levels, but racemes and seeds from the Fe‐deficient treatment accumulated significantly higher concentrations of Cd than those from the Fe‐sufficient treatment. For example, at the highest substrate Cd concentration, the Cd bioaccumulation factor (tissue Cd concentration predicted from polynomial response surface equations describing the relationship between tissue and substrate Cd concentrations divided by nominal substrate Cd concentration) for rosettes was 3.2 in both Fe treatments, but raceme Cd bioaccumulation factors were 1.7 and 0.9, and seed Cd bioaccumulation factors were 0.4 and 0.2 in the Fe‐deficient and Fe‐sufficient treatments, respectively. Rosette biomass was largely unaffected by tissue Cd level, but at tissue Cd concentrations of at least 1.26 mmol kg−1 for racemes and 0.32 mmol kg−1 for seeds, substantial biomass reductions occurred. Analysis of the uptake of other elements by Arabidopsis suggests that the greater accumulation of Cd by plants in the Fe‐deficient treatment may be a consequence of the species' Fe efficiency mechanisms. Our results support the hypothesis that uptake of toxic elements by Fe‐efficient species can be enhanced when the plants are growing in Fe‐deficient soils.
Growth Responses of 53 Open‐Pollinated Loblolly Pine Families to Ozone and Acid Rain
Authors: McLaughlin S. B. , Layton P. A. , Adams M. B. , Edwards N. T. , Hanson P. J. , O'Neill E. G. , Roy W. K. 
Published: July 2010

AbstractField exposures of 9950 containerized 12‐wk‐old loblolly pine (Pinus taeda L.) seedlings representing 53 commercially important, open‐pollinated families were conducted to evaluate individual and interactive effects of acid rain and O3 on growth response. A 36‐plot field research facility comprised of 33 open‐top chambers and three open plots was used to test effects of five O3 levels that included ambient (A) and seasonally integrated levels that were 0.53, 1.10, 1.58, or 2.15 times ambient. Individual effects of three levels of simulated acid rain (pH 3.3, 4.5, and 5.2) as well as their interaction with O3 at 0.53A, 1.58A, and 2.15A levels were also included. Exposure to ambient air reduced average growth in height (26%), diameter (5%), and volume (14%) compared with growth of seedlings exposed to a 47% lower dose in charcoal filtered (CF) air. Responses to increasing O3 above ambient levels varied widely between families, became increasingly inhibitory at the highest O3 levels, but did not significantly exceed growth reductions found in ambient air. Diameter growth was reduced in most families by all levels of O3 addition. Acid rain caused a general stimulation of height growth at ambient levels (pH 4.5), while both height and diameter growth were reduced at a mean pH of 3.3. Significant antagonism between rainfall acidity and O3 effects on height and biomass increment was detected with increasing pollutant concentrations. Ozone reduced root/shoot biomass in most families, while acid rain did not.
Sorption and Retention of Herbicides in Vertically Oriented Earthworm and Artificial Burrows
Authors: Stehouwer R. C. , Dick W. A. , Traina S. J. 
Published: July 2010

AbstractIn many temperate region no‐tillage agro‐ecosystems, the vertically oriented burrows of the nightcrawler earthworm (Lumbricus terrestris L.) function as preferential flow paths and may promote the rapid downward transport of surface‐applied chemicals. The burrows of nightcrawlers, however, are lined with a material that is enriched in organic C relative to the surrounding soil matrix that may affect transport of organic chemicals. Vie investigated the effect of this lining on the sorption and retention of four herbicides: atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N(2‐methoxy‐1‐methylethyl)acetamide], dicamba (3,6‐dichloro‐2‐methoxybenzoic acid), and primisulfuron [3‐[4,6‐bis(difluoromethoxy)‐pyrimidin‐2yl]‐1‐(2‐methoxy carbonylphenyl sulfonyl) urea]. Batch sorption isotherms were determined using burrow lining and bulk soil collected from seven depth intervals from 0 to 50 cm. Sorption of the more strongly sorbed herbicides (atrazine and metolachlor) was enhanced by a factor of up to three on burrow lining relative to bulk soil, while there was little or no enhancement of the weakly sorbed herbicides (dicamba and primisulfuron). Transport and retention of these herbicides was measured in intact burrows in undisturbed soil blocks. Concentrations of the two strongly sorbed herbicides decreased during flow through nightcrawler and artificial (unlined) burrows, with the largest decreases occurring in earthworm burrows. Concentrations of the two weakly sorbed herbicides decreased very little during flow through either type of burrow. Retained herbicide concentrations were higher in nightcrawler than in artificial burrow walls, and decreases in concentration from the surface to the second 1‐mm wall layer were greater in nightcrawler than in artificial burrow walls. These results indicate the material lining nightcrawler burrows may significantly retard herbicide transport during lateral flow into and out of burrows.