bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uptake and Release of Cesium‐137 by Five Plant Species as Influenced by Soil Amendments in Field Experiments
Authors: Fuhrmann Mark , Lasat Mitch , Ebbs Stephen , Cornish Jay , Kochian Leon 
Published: June 2010

ABSTRACTPhytoextraction field experiments were conducted on soil contaminated with 0.39 to 8.7 Bq/g of 137Cs to determine the capacity of five plant species to accumulate 137Cs and the effects of three soil treatments on uptake. The plants tested were redroot pigweed (Amaranthus retroflexus L. var. aureus); a mixture of redroot pigweed and spreading pigweed (A. graecizans L.); purple amaranth (A. cruteus L.) × Powell's amaranth (A. powellii S. Watson), referred to here as the amaranth hybrid; Indian mustard [Brassica juncea (L.) Czern.]; and cabbage (Brassica oleracea L. var. capitata). For control plants, the concentration ratios (CR) of 137Cs were greatest for redroot pigweed and the amaranth hybrid, with average CR values of 1.0 ± 0.24 and 0.95 ± 0.14, respectively. The lowest value was for Indian mustard at 0.36 ± 0.10. The soil treatments included (i) application of NH4NO3 solution to the soil after plants had matured, (ii) addition of composted manure to increase organic matter content of the soil, (iii) combination of the manure and ammonium solution treatments, and (iv) controls. The ammonium solution gave little overall increase in accumulation of 137Cs. The use of composted manure also had little influence, but the combination of the composted manure with application of ammonium solutions had a distinctly negative effect on plant uptake of 137Cs. On average the fraction of 137Cs taken up from the soil was reduced by 57.4 ± 1.2% compared with controls. This was the result of release of competing ions, primarily Ca, from the manure and was observed across all five plant species tested. The application of ammonium solution took place in the last two weeks before harvest. The reduction of plant 137Cs content, by addition of the ammonium solution, as it interacted with the manure, indicates that substantial quantities 137Cs can be released from the shoots of plants as a result of sudden changes in soil solution chemistry.
Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment
Authors: Smith R. V. , Lennox S. D. , Bailey J. S. 
Published: June 2010

ABSTRACTAn upward trend in soluble reactive phosphorus (SRP) concentrations in Northern Ireland rivers leading to increased eutrophication has been reported for the last two decades. To identify if a similar trend could be observed in land drainage waters SRP and other P fractions were measured weekly from 1989 to 1997 in land drainage from a 9‐ha grassland catchment in Northern Ireland that had a mean P surplus applied of 23.4 kg P ha−1 yr−1 Regressions of annual median concentrations of P fractions in land drainage waters against time for 1989 through to 1997 showed significant increases of SRP and soluble unreactive phosphorus (SUP) of 2.4 and 1.2 μg P L−1 yr−1, respectively. However, the annual flow‐weighted concentrations and loads of all P fractions did not show significant increases with time. During the period 1998–2000 a change of management was introduced when only maintenance dressings of P were applied to the catchment according to Ministry of Agriculture, Fisheries and Food guidelines. This resulted in significant reductions in SRP concentrations in 2000 compared with 1997.
Aluminum Effect on Dissolution and Precipitation under Hyperalkaline Conditions
Authors: Qafoku Nikolla P. , Ainsworth Calvin C. , Szecsody James E. , Qafoku Odeta S. 
Published: June 2010

ABSTRACTSubstantial amounts of self‐boiling, Al‐rich, hyperalkaline, and saline high‐level waste fluids (HLWF) were deposited to the vadose zone at the Hanford Site, in Washington State. The objective of this study was to investigate the effects of similar fluids on the extent of dissolution and precipitation in the sediments. Metal‐ and glass‐free systems were used to conduct batch experiments at 323 K under CO2 and O2 free conditions. Base‐induced dissolution of the soil minerals was rapid in the first 48 h as indicated by immediate releases of Si and Fe into the soil solution. Potassium release lagged behind and dissolution of K‐bearing minerals (mica and K‐feldspar) proceeded faster only after 2 to 3 d of the experiment. Silicon and Fe release exhibited high dependence on aqueous [Al] (rate orders <−1), because Al decreased free OH concentration in the contact solution and probably inhibited soil mineral dissolution. Initial K release exhibited low dependence on [Al] (fractional rate orders). Initial dissolution rates calculated based on Si release varied with aqueous [Al] from 29.47 to 4.35 × 10−12 mol m−2 s−1 Aluminum participated in the formation of the secondary phases (precipitation rates of 10−8 mol s−1) but the overall precipitation rate of alumino‐silicate secondary phases was probably controlled by aqueous [Si] (rates of 10−9, and rate constants between 0.0054 and 0.0084 h−1). The changes in the soil solution chemistry (release of K, Si, Fe, and other elements) may play a significant role in the fate of radionuclides and contaminants like Cs, Sr, Cr, and U in the Hanford sediments.
An Integrated Chemical, Thermal, and Microbiological Approach to Compost Stability Evaluation
Authors: Mondini Claudio , Dell'Abate Maria Teresa , Leita Liviana , Benedetti Anna 
Published: June 2010

ABSTRACTThe evaluation of compost stability is of the utmost importance for the reliability of composting as a recycling strategy. To date there is no single parameter that can give a sure indication of the stability of composts from different starting materials. This paper investigates different methods of evaluating the dynamics of transformation of materials and the stability level of the end products in a composting process. The following parameters were determined on compost samples of different ages from cotton (Gossypium herbaceum L.) cardings and yard wastes: humification index (HI), degree of humification (DH), thermogravimetry (TG) microbial biomass C (BC), and ninhydrin‐reactive N (BNIN). Finally, from TG, derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC) thermal stability parameters were deduced. Humification parameters in the end products (0.2 and 81% for HI and DH, respectively) showed the effective stability reached by the organic matter (OM). Thermal analysis evidenced the presence of two main organic pools with different thermal stability. During composting a relative increase in the more stable organic pool was indicated by the variation of the thermostability index R1 from 0.41 to 0.74. The parameter R1 was significantly correlated with both HI (r = −0.94; P < 0.05) and DH (r = 0.97; P < 0.05). Microbial biomass content dynamics reflected the availability of readily decomposable substrates. The ratio between BNIN and total N in the end product was 0.96%, indicating a good stability level. The simultaneous application of different approaches, considering different properties of composting materials, provides a more complete description of the stability and quality reached by the organic materials.
Water‐Quality Effects of Incorporating Poultry Litter into Perennial Grassland Soils
Authors: Pote D. H. , Kingery W. L. , Aiken G. E. , Han F. X. , Moore P. A. , Buddington K. 
Published: June 2010

ABSTRACTPoultry litter provides a rich source of nutrients for perennial forages, but the usual practice of surface‐applying litter to pastures can degrade water quality by allowing nutrients to be transported from fields in surface runoff, while much of the NH4–N volatilizes. Incorporating litter into the soil can minimize such problems in tilled systems, but has not been used for perennial forage systems. In this study, we minimized disturbance of the crop, thatch, and soil structure by using a knifing technique to move litter into the root zone. Our objective was to determine effects of poultry litter incorporation on quantity and quality of runoff water. Field plots were constructed on a silt loam soil with well‐established bermudagrass [Cynodon dactylon (L.) Pers.] and mixed grass forage. Each plot had 8 to 10% slopes, borders to isolate runoff, and a downslope trough with sampling pit. Poultry litter was applied (5.6 Mg ha−1) by one of three methods: surface‐applied, incorporated, or surface‐applied on soil‐aeration cuts. There were six treatment replications and three controls (no litter). Nutrient concentrations and mass losses in runoff from incorporated litter were significantly lower (generally 80–95% less) than in runoff from surface‐applied litter. By the second year of treatment, litter‐incorporated soils had greater rain infiltration rates, water‐holding capacities, and sediment retention than soils receiving surface‐applied litter. Litter incorporation also showed a strong tendency to increase forage yield.
Nitrite Formation and Nitrous Oxide Emissions as Affected by Reclaimed Effluent Application
Authors: Master Y. , Laughlin R. J. , Stevens R. J. , Shaviv A. 
Published: June 2010

ABSTRACTThe effect of irrigation with reclaimed effluent (RE) (after secondary treatment) on the mechanisms and rates of nitrite formation, N2O emissions, and N mineralization is not well known. Grumosol (Chromoxerert) soil was incubated for 10 to 14 d with fresh water (FW) and RE treated with 15NO3− and 15NH4+ to provide a better insight on N transformations in RE‐irrigated soil. Nitrite levels in RE‐irrigated soil were one order of magnitude higher than in FW‐irrigated soil and ranged between 15 to 30 mg N kg−1 soil. Higher levels of NO2− were observed at a moisture content of 60% than at 70% and 40% w/w. Nitrite levels were also higher when RE was applied to a relatively dry Grumosol (20% w/w) than at subsequent applications of RE to soil at 40% w/w. Isotopic labeling indicated that the majority of NO2− was formed via nitrification. The amount of N2O emitted from RE‐treated Grumosol was double the amount emitted from FW treatments at 60% w/w. Nitrification was responsible for about 42% of the emissions. The N2O emission from the RE‐treated bulk soil (passing a 9.5‐mm sieve) was more than double the amount formed in large aggregates (4.76–9.5 mm in diameter). No dinitrogen was detected under the experimental conditions. Results indicate that irrigation with secondary RE stimulates nitrification, which may enhance NO3− leaching losses. This could possibly be a consequence of long‐term exposure of the nitrifier population to RE irrigation. Average gross nitrification rate estimates were 11.3 and 15.8 mg N kg−1 soil d−1 for FW‐ and RE‐irrigated bulk soils, respectively. Average gross mineralization rate estimates were about 3 mg N kg−1 soil d−1 for the two water types.
Uncertainty and Sensitivity Analysis of Spatial Predictions of Heavy Metals in Wheat
Authors: Brus D. J. , Jansen M. J. W. 
Published: June 2010

ABSTRACTHeavy metals seriously threaten the health of human beings when they enter the food chain. Therefore, policymakers require precise predictions of heavy metal concentrations in agricultural crops. In this paper we quantify the uncertainty of regression predictions of Cd and Pb in wheat (Triticum aestivumL.) and the contributions to the uncertainties in these predictions associated with inputs to the regression model. For each node of the 500‐ × 500‐m grid covering the arable soils in the Netherlands, a latin hypercube sample size of 1000 is constructed from the uncertainty distributions of the explanatory variables (pH, soil organic matter [SOM], and heavy metal concentration in soil), the regression coefficients, and the random term of the regression model. This sample is used as input for the regression model to obtain 1000 values from the uncertainty distributions of the log(Cd) and log(Pb) concentration in wheat. There were no nodes where the recent EU quality standards for Cd and Pb (0.2 mg kg−1fresh wt.) in wheat were almost certain to be exceeded. For most nodes with clay soils, the quality standard for Cd in wheat almost certainly will not be exceeded; for Pb this is much less certain. The uncertainty in the Cd concentration in soil contributes most to the uncertainty in the predicted Cd concentrations in wheat (36% on the average), followed by the random term of the regression model (23%). For Pb the contribution of the random term is by far the largest (52%).
Polycyclic Aromatic Hydrocarbon Storage in a Typical Cerrado of the Brazilian Savanna
Authors: Wilcke Wolfgang , Krauss Martin , Lilienfein Juliane , Amelung Wulf 
Published: June 2010

ABSTRACTThere may be important biological sources of polycyclic aromatic hydrocarbons (PAHs) to the global environment, particularly of naphthalene, phenanthrene, and perylene, that originate in the tropics. We (i) studied the distribution of PAHs among different compartments of a typical Cerrado to locate their sources and (ii) quantified the PAH storage of this ecosystem. The sum of 20 PAH (Σ20PAHs) concentrations ranged from 25 to 666 μg kg−1in plant tissue, 7.4 to 32 μg kg−1in litterfall, 206 to 287 μg kg−1in organic soil, and 10 to 79 μg kg−1in mineral soil. Among the living biomass compartments, the bark had the highest mean PAH concentrations and coarse roots the lowest, indicating that PAHs in the plants originated mainly from aboveground sources. Naphthalene and phenanthrene were the most abundant individual PAHs, together contributing 33 to 96% to the Σ20PAHs concentrations. The total storage of the Σ20PAHs in Cerrado was 7.5 mg m−2to a 0.15‐m soil depth and 49 mg m−2to a 2‐m soil depth. If extrapolated to the entire Brazilian Cerrado region, roughly estimated storages of naphthalene and phenanthrene correspond to 7300 and 400 yr of the published annual emissions in the United Kingdom, respectively. The storage of benzo[a]pyrene, a typical marker for fossil fuel combustion, in the Cerrado only corresponds to 0.19 yr of UK emissions. These results indicate that the Brazilian savanna comprises a huge reservoir of naphthalene and phenanthrene originating most likely from the aboveground parts of the vegetation or associated organisms. Thus, the Cerrado might be a globally important source of these PAHs.
Short‐ and Longer‐Term Effects of the Willow Root System on Metal Extractability in Contaminated Dredged Sediment
Authors: Vervaeke P. , Tack F. M. G. , Lust N. , Verloo M. 
Published: June 2010

ABSTRACTWillow (Salix spp.) stands are often proposed as vegetation covers for the restoration and stabilization of contaminated and derelict land. Planting willows on dredged sediment disposal sites for biomass production can be an alternative to traditional capping techniques. However, with the introduction of willow stands on dredged sediment disposal sites, the possibility of increased contaminant availability in the root zone must be acknowledged as it can increase the risk of leaching. Two trials investigated the availability of Cd, Zn, Cu, and Pb in the root zones of willows grown on contaminated sediment. To assess the effects of willow root growth on metal extractability and mobility, bulk and rhizosphere sediment samples were extracted with deionized water, ammonium acetate at pH 7, and ammonium acetate–EDTA at pH 4.65. A rhizobox experiment was used to investigate the short‐term effect of willow roots on metal availability in oxic and anoxic sediment. Longer‐term effects were assessed in a field trial. The rhizobox trial showed that Cd, Zn, and Cu extractability in the rhizosphere increased while the opposite was observed for Pb. This was attributed to the increased willow‐induced oxidation rate in the root zone as a result of aeration and evapotranspiration, which masked the direct chemical and biological influences of the willow roots. The field trial showed that Cu and Pb, but not Cd, were more available in the root zone after water and ammonium acetate (pH 7) extraction compared with the bulk sediment. Sediment in the root zone was better structured and aggregated and thus more permeable for downward water flows, causing leaching of a fraction of the metals and significantly lower total contents of Cd, Cu, and Pb. These findings indicate that a vegetation cover strategy to stabilize sediments can increase metal availability in the root zone and that potential metal losses to the environment should be considered.
Overland and Near‐Surface Transport ofCryptosporidium parvumfrom Vegetated and Nonvegetated Surfaces
Authors: Trask Jennifer R. , Kalita Prasanta K. , Kuhlenschmidt Mark S. , Smith Ronald D. , Funk Ted L. 
Published: June 2010

ABSTRACTUnderstanding microbial pathogen transport patterns in overland flow is important for developing best management practices for limiting microbial transport to water resources. Knowledge about the effectiveness of vegetative filter strips (VFS) to reduce pathogen transport from livestock confinement areas is limited. In this study, overland and near‐surface transport ofCryptosporidium parvumhas been investigated. Effects of land slopes, vegetation, and rainfall intensities on oocyst transport were examined using a tilting soil chamber with two compartments, one with bare ground and the other with brome (Bromus inermisLeyss.) vegetation. Three slope conditions (1.5, 3.0, and 4.5%) were used in conjunction with two rainfall intensities (25.4 and 63.5 mm/h) for 44 min using a rainfall simulator. The vegetative surface was very effective in reducingC. parvumin surface runoff. For the 25.4 mm/h rainfall, the total percent recovery of oocysts in overland flow from the VFS varied from 0.6 to 1.7%, while those from the bare ground condition varied from 4.4 to 14.5%. For the 63.5 mm/h rainfall, the recovery percentages of oocysts varied from 0.8 to 27.2% from the VFS, and 5.3 to 59% from bare‐ground conditions. For all slopes and rainfall intensities, the total (combining both surface and near‐surface) recovery ofC. parvumoocysts was considerably less from the vegetated surface than those from the bare‐ground conditions. These results indicate that the VFS can be a best management practice for controllingC. parvumin runoff from animal production facilities.
Removal of Organic Matter and Nitrogen from River Water in a Model Floodplain
Authors: Chung Jong‐Bae , Kim Seung‐Hyun , Jeong Byeong‐Ryong , Lee Young‐Deuk 
Published: June 2010

ABSTRACTA significant improvement in river water quality cannot be expected unless nonpoint‐source contaminants are treated in addition to the further treatment of point‐source contaminants. If river water is sprayed over a floodplain, the consequent water filtration through the sediment profile can simultaneously remove organic matter and nitrogen in the water through aerobic and denitrifying reactions. This hypothesis was tested using lysimeters constructed from polyvinyl chloride (PVC) pipe (150 cm long, 15 cm in diameter) packed with loamy sand floodplain sediment. Water was applied to the top of the lysimeters at three different flow rates (48, 54, and 68 mm d−1). Concentrations of NO3 and dissolved oxygen (DO), chemical oxygen demand (COD), and redox potential (Eh) in the water were measured as functions of depth after the system reached steady states for both water flow and reactions. At the rate of 68.0 mm d−1, a reducing condition for denitrification developed below the 5‐cm depth due to the depletion of O2 by organic matter degradation in the surface oxidizing layer; Eh and DO were below 205 mV and 0.4 mg L−1, respectively. At a depth of 70 cm, COD and NO3–N concentration decreased to 5.2 and 3.8 mg L−1 from the respective influent concentrations of 17.1 and 6.2 mg L−1 Most biodegradable organic matter was removed during flow and further removal of NO3 was limited by the lack of an electron donor (i.e., organic matter). These results indicate that the floodplain filtration technique has great promise for treatment of contaminated river water.
Impact of Preferential Flow at Varying Irrigation Rates by Quantifying Mass Fluxes
Authors: Gish T. J. , Kung K.‐J. S. , Perry D. C. , Posner J. , Bubenzer G. , Helling C. S. , Kladivko E. J. , Steenhuis T. S. 
Published: June 2010

ABSTRACTSolute concentration and soluble dye studies inferring that preferential flow accelerates field‐scale contaminant transport are common but flux measurements quantifying its impact are essentially nonexistent. A tile‐drain facility was used to determine the influence of matrix and preferential flow processes on the flux of mobile tracers subjected to different irrigation regimes (4.4 and 0.89 mm h−1) in a silt loam soil. After tile outflow reached steady state either bromide (Br; 280 kg ha−1) or pentafluorobenzoic acid (PFBA; 121 kg ha−1) was applied through the irrigation system inside a shed (3.5 × 24 m). Bromide fluxes were monitored at an irrigation rate of 4.4 mm h−1 while PFBA fluxes were monitored at an irrigation rate of 0.89 mm h−1 At 4.4 mm h−1 nearly one‐third of the surface‐applied Br was recovered in the tile line after only 124 mm of irrigation and was poorly fit by the one‐dimensional convective–dispersive equation (CDE). On the other hand, the one‐dimensional CDE fit the main PFBA breakthrough pattern almost perfectly, suggesting the PFBA transport was dominated by matrix flow. Furthermore, after 225 mm of water had been applied, less than 2% of the applied PFBA had been leached through the soil compared with more than 59% of the applied Br. This study demonstrates that the methodology of applying a narrow strip of chemical to a tile drain facility is appropriate for quantifying chemical fluxes at the small‐field scale and also suggests that there may be a critical input flux whereby preferential flow is initiated.
Bacterial Removal and Protozoan Grazing in Biological Sand Filters
Authors: Bomo Anne‐Marie , Stevik Tor Kristian , Hovi Ine , Hanssen Jon Fredrik 
Published: June 2010

ABSTRACTThe objective of the study was to investigate the importance of protozoan predation as a biological removal mechanism in sand filters used for purification of bacteria from wastewater. Eleven sand filter columns were seeded with a high dose of wastewater (70 mm d−1) and a high concentration (108 colony forming units [CFU] mL−1) of Aeromonas hydrophila (American Type Culture Collection [ATCC] 14715) for a period of 30 d. Water samples from three filter outlets were analyzed for the concentration of A. hydrophila In addition, one filter column was sacrificed each sampling day for the quantification of A. hydrophila, culturable bacteria (heterotrophic plate counts, HPC), total bacterial counts, and protozoa in the sand. The mean removal efficiency of A. hydrophila in the sand filter columns was 4.7 log units. The concentration of A. hydrophila in the sand filter effluent, however, had a clearly time‐dependent pattern from high (log 6) and unstable concentrations to low and more stable levels (log 2). The removal efficiency of A. hydrophila correlated significantly (P = 0.0005, r2 = 0.6) with numbers of protozoa in the sand filters. Significantly higher (P < 0.05) concentrations of A. hydrophila were observed in sand filter effluents from columns treated with the protozoan inhibitor cycloheximide, compared with nontreated columns. Results from the present study show that protozoan grazing plays an important role as a bacterial removal mechanism in sand infiltration systems.