bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissolution and Transport of TNT, RDX, and Composition B in Saturated Soil Columns
Authors: Dontsova Katerina M. , Yost Sally L. , Šimunek Jiri , Pennington Judith C. , Williford Clint W. 
Published: October 2006

ABSTRACTLow‐order detonations and blow‐in‐place procedures on military training ranges can result in residual solid explosive formulations to serve as distributed point sources for ground water contamination. This study was conducted to determine if distribution coefficients from batch studies and transport parameters of pure compounds in solution adequately describe explosive transport where compounds are present as solid particles in formulations. Saturated column transport experiments were conducted with 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), and the explosive formulation, Composition B (Comp B) (59.5 ± 2.0% RDX, 39.5 ± 2.3% TNT, and 1% wax) in solid and dissolved forms. The two soils used were Plymouth loamy sand (mesic, coated Typic Quartzipsamments) from Camp Edwards, MA and Adler silt loam (coarse‐silty, mixed, superactive, thermic Fluvaquentic Eutrudepts) from Vicksburg, MS. Interrupted flow experiments were used to determine if explosives were at equilibrium distribution between soil and solution phases. The HYDRUS‐1D code was used to determine fate and transport parameters. Results indicated that sorption of high explosives was rate limited. The behavior of dissolved Comp B was similar to the behavior of pure TNT and RDX. Behavior of solid Comp B was controlled by dissolution that depended on physical properties of the Comp B sample. Adsorption coefficients determined by HYDRUS‐1D were different from those determined in batch tests for the same soils. Use of parameters specific to formulations will improve fate and transport predictions.
Emission of the Greenhouse Gases Nitrous Oxide and Methane from Constructed Wetlands in Europe
Authors: S⊘vik A. K. , Augustin J. , Heikkinen K. , Huttunen J. T. , Necki J. M. , Karjalainen S. M. , Kl⊘ve B. , Liikanen A. , Mander Ü. , Puustinen M. , Teiter S. , Wachniew P. 
Published: October 2006

ABSTRACTThe potential atmospheric impact of constructed wetlands (CWs) should be examined as there is a worldwide increase in the development of these systems. Fluxes of N2O, CH4, and CO2 have been measured from CWs in Estonia, Finland, Norway, and Poland during winter and summer in horizontal and vertical subsurface flow (HSSF and VSSF), free surface water (FSW), and overland and groundwater flow (OGF) wetlands. The fluxes of N2O–N, CH4–C, and CO2–C ranged from −2.1 to 1000, −32 to 38 000, and −840 to 93 000 mg m−2 d−1, respectively. Emissions of N2O and CH4 were significantly higher during summer than during winter. The VSSF wetlands had the highest fluxes of N2O during both summer and winter. Methane emissions were highest from the FSW wetlands during wintertime. In the HSSF wetlands, the emissions of N2O and CH4 were in general highest in the inlet section. The vegetated ponds in the FSW wetlands released more N2O than the nonvegetated ponds. The global warming potential (GWP), summarizing the mean N2O and CH4 emissions, ranged from 5700 to 26000 and 830 to 5100 mg CO2 equivalents m−2 d−1 for the four CW types in summer and winter, respectively. The wintertime GWP was 8.5 to 89.5% of the corresponding summertime GWP, which highlights the importance of the cold season in the annual greenhouse gas release from north temperate and boreal CWs. However, due to their generally small area North European CWs were suggested to represent only a minor source for atmospheric N2O and CH4
Removal of Technetium from Solution by Algal Flagellate Euglena gracilis
Authors: Ishii Nobuyoshi , Uchida Shigeo 
Published: October 2006

ABSTRACTBased on limited data for the removal of radioactive 99Tc by freshwater phytoplankton, it has been thought that phytoplankton are unsuitable for remediation of 99Tc‐contaminated waters. This work sought to verify the validity of this assumption by studying the removal of 99TcO4− by freshwater and brackish water phytoplankton. The phytoplankton used were Euglena gracilis, Chlamydomonas pulsatilla, Chlorella vulgaris, and Spirulina platensis Each of them was incubated for 63 d, and the removal of 99Tc from solution was periodically determined. Significant removal of 99Tc was observed only for E. gracilis, and the maximum removal was 70% of the total 99Tc added. The killed cells of E. gracilis, however, removed hardly any 99Tc. When E. gracilis cells were washed with fresh culture medium, only 13% of the total 99Tc was desorbed. These results suggested that intracellular uptake of 99Tc by E. gracilis occurred. These results are the first documented example of significant removal of 99Tc by planktonic microalgae.
Evaluation of Extracted Organic Carbon and Microbial Biomass as Stability Parameters in Ligno‐Cellulosic Waste Composts
Authors: Mondini Claudio , Sánchez‐Monedero Miguel A. , Sinicco Tania , Leita Liviana 
Published: October 2006

ABSTRACTExtracted organic C and microbial biomass were evaluated as stability parameters in 3 different ligno‐cellulosic waste composts. Organic C was extracted by both water and alkali and further separated in humic‐like carbon (HLC) and nonhumic carbon (NHC). Conventional humification parameters, such as humification index and degree of humification were calculated from NHC and HLC. Microbial biomass carbon (BC) was determined as an indicator of the degree of biochemical transformation, whereas ninhydrin reactive N (BNIN) was measured to obtain the stability parameter BNIN/NTOT (NTOT, total N). The water‐extracted organic C did not provide reliable information on the transformations underwent by the ligno‐cellulosic wastes during composting, since its content remained almost unaltered during the whole process. In contrast, parameters based on the alkali‐extracted organic C and microbial biomass clearly reflected organic matter (OM) changes during the process. There was an increase in the net amount of HLC in the alkali extracts throughout composting, especially in the first 7 to 12 wk of the process, as well as a relative enrichment of HLC with respect to NHC. Values of humification index and degree of humification in end products were consistent with an adequate level of compost stability. The stability parameter BNIN/NTOT showed to be a reliable indicator of stability in ligno‐cellulosic wastes. Parameters based on the alkali‐extracted C and microbial biomass clearly reflected the transformation of the OM during composting and can be used as stability parameters in ligno‐cellulosic waste composts.
Estimating Plant‐Available Nitrogen Release from Manures, Composts, and Specialty Products
Authors: Gale Eric S. , Sullivan Dan M. , Cogger Craig G. , Bary Andy I. , Hemphill Delbert D. , Myhre Elizabeth A. 
Published: October 2006

ABSTRACTRecent adoption of national rules for organic crop production have stimulated greater interest in meeting crop N needs using manures, composts, and other organic materials. This study was designed to provide data to support Extension recommendations for organic amendments. Specifically, our objectives were to (i) measure decomposition and N released from fresh and composted amendments and (ii) evaluate the performance of the model DECOMPOSITION, a relatively simple N mineralization/immobilization model, as a predictor of N availability. Amendment samples were aerobically incubated in moist soil in the laboratory at 22°C for 70 d to determine decomposition and plant‐available nitrogen (PAN) (n = 44), and they were applied preplant to a sweet corn crop to determine PAN via fertilizer N equivalency (n = 37). Well‐composted materials (n = 14) had a single decomposition rate, averaging 0.003 d−1 For uncomposted materials, decomposition was rapid (>0.01 d−1) for the first 10 to 30 d. The laboratory incubation and the full‐season PAN determination in the field gave similar estimates of PAN across amendments. The linear regression equation for lab PAN vs. field PAN had a slope not different from one and a y‐intercept not different than zero. Much of the PAN released from amendments was recovered in the first 30 d. Field and laboratory measurements of PAN were strongly related to PAN estimated by DECOMPOSITION (r2 > 0.7). Modeled PAN values were typically higher than observed PAN, particularly for amendments exhibiting high initial NH4–N concentrations or rapid decomposition. Based on our findings, we recommend that guidance publications for manure and compost utilization include short‐term (28‐d) decomposition and PAN estimates that can be useful to both modelers and growers.
Influence of Geomorphological Variability in Channel Characteristics on Sediment Denitrification in Agricultural Streams
Authors: Opdyke Matthew R. , David Mark B. , Rhoads Bruce L. 
Published: October 2006

ABSTRACTWithin fluvial systems, the spatial variability of geomorphological characteristics of stream channels and associated streambed properties can affect many biogeochemical processes. In agricultural streams of the midwestern USA, it is not known how geomorphological variability affects sediment denitrification rates, a potentially important loss mechanism for N. Sediment denitrification was measured at channelized and meandering headwater reaches in east‐central Illinois, a region dominated by intensive agriculture and high NO3–N stream export, between June 2003 and February 2005 using the chloramphenicol‐amended acetylene inhibition procedure. Sediment denitrification rates were greatest in separation zones, ranging from 0.6 to 76.4 mg N m−2h−1, compared with riffles, point bars, pools, and a run ranging from 0 to 36.5 mg N m−2h−1Differences in benthic organic matter (r= 0.70) and the percentage of fine‐grained sediments (r= 0.93) in the streambeds controlled much of the spatial variations in sediment denitrification among the geomorphological features. Although two meandering study reaches removed 390 and 99% more NO3–N by sediment denitrification than adjacent channelized reaches, NO3–N loss rates from all reaches were between 0.1 and 15.7% d−1, except in late summer. Regardless of geomorphological characteristics, streams in east‐central Illinois were not able to process the high NO3–N loads, making sediment denitrification in this region a limited sink for N.
Performance of Grass Barriers and Filter Strips under Interrill and Concentrated Flow
Authors: Blanco‐Canqui Humberto , Gantzer Clark J. , Anderson S. H. 
Published: October 2006

ABSTRACTEffectiveness of grass barriers and vegetative filter strips (FS) for reducing transport of sediment and nutrients in runoff may depend on runoff flow conditions. We assessed the performance of (1) switchgrass (Panicum virgatum L.) barriers (0.7 m) planted above fescue (Festuca arundinacea Schreb.) filter strips under interrill (B‐FS) and concentrated flow (CF‐B‐FS), and (2) fescue alone under interrill (FS) and concentrated flow (CF‐FS) for reducing runoff, sediment, nitrogen (N), and phosphorus (P) loss from fallow plots on a Mexico silt loam. We compared exclusively the performance of barriers and filter strips separately under interrill and concentrated flow. Runoff and sediment were sampled at 1 m above and at 0.7, 4, and 8 m below the downslope edge of the sediment source area. Filter strips under interrill flow reduced 80% and those under concentrated flow reduced 72% of sediment at 0.7 m (P < 0.01). With the addition of supplemental runoff simulating runoff from a larger sediment source area, FS reduced 80%, but CF‐FS reduced only 60% of sediment. The FS reduced organic N and NO3–N by an additional 50% (P < 0.01) more than CF‐FS at 0.7 m. Although the effectiveness of both treatments increased with increasing width, CF‐FS removed less sediment than FS alone at 8 m (P < 0.04). In contrast, barriers above filter strips under interrill and concentrated flow were equally effective at 8 m; decreasing runoff by 34%, sediment by 99%, and nutrients by 70%. Thus, barriers combined with FS can be an effective alternative to FS alone for sites where concentrated flows may occur.
Biosolids Affect Soil Barium in a Dryland Wheat Agroecosystem
Authors: Ippolito J. A. , Barbarick K. A. 
Published: October 2006

ABSTRACTIn December 2003, the USEPA released an amended list of 15 “candidate pollutants for exposure and hazard screening” with regard to biosolids land application, including Ba. Therefore, we decided to monitor soil Ba concentrations from a dryland wheat (Triticum aestivum L.)–fallow agroecosystem experiment. This experiment received 10 biennial biosolids applications (1982–2003) at rates from 0 to 26.8 dry Mg ha−1 per application year. The study was conducted on a Platner loam (Aridic Paleustoll), ∼30 km east of Brighton, CO. Total soil Ba, as measured by 4 M HNO3, increased with increasing biosolids application rate. In the soil‐extraction data from 1988 to 2003, however, we observed significant (P < 0.10) linear or exponential declines in ammonium bicarbonate–diethylenetriaminepentaacetic acid (AB–DTPA) extractable Ba concentrations as a function of increasing biosolids application rates. This was observed in 6 of 7 and 3 of 7 yr for the 0‐ to 20‐ and 20‐ to 60‐cm soil depths, respectively. Results suggest that while total soil Ba increased as a result of biosolids application with time, the mineral form of Ba was present in forms not extractable with AB–DTPA. Scanning electron microscopy using energy dispersive spectroscopy verified soil Ba–S compounds in the soil surface, probably BaSO4 Wet chemistry sequential extraction suggested BaCO3 precipitation was increasing in the soil subsurface. Our research showed that biosolids application may increase total soil Ba, but soil Ba precipitates are insoluble and should not be an environmental concern in similar soils under similar climatic and management conditions.
Phosphorus Sorption by Sediments in a Southeastern Coastal Plain In‐Stream Wetland
Authors: Novak J. M. , Watts D. W. 
Published: October 2006

ABSTRACTA close relationship has been reported between sediment organic C (SedOC) content and its P sorption capacity (Pmax) and total P (TP) concentration. Phosphorus sorbed to organically complexed cations is a proposed explanation for this relationship. The objectives of this study were (i) to determine relationships between in‐stream wetland SedOC content and both the sediment's Pmax and TP concentrations, and (ii) to ascertain the role of both organically complexed and oxalate‐extractable cations on the sediment Pmax and TP values. The sediment's oxalate‐extractable Fe (Feox) and Al (Alox) contents were determined using acidified ammonium oxalate, while sodium pyrophosphate was used to extract organically complexed cations (Alpryo, Capyro, Fepyro, Mgpyro, and Mnpyro). Both the sediment's Pmax and TP contents were strongly correlated with its SedOC concentration (r2 > 0.90, P < 0.001). Only the Alox contents were significantly correlated with TP and Pmax, suggesting that amorphous Al forms have an important role in P sorption. All five pyrophosphate‐extracted cations were significantly correlated with SedOC contents. Regression analyses showed that the Alpyro accounted for 88% of the variation in sediment Pmax values, whereas a combination of Alpyro and Capyro accounted for 98% of the variation in sediment TP concentrations. Additionally, Al and Ca chelated by SedOC compounds also have an important role in P binding and indicate that a linkage exists between the wetlands SedOC and Pmax content and its ability to accumulate TP. This study identified that two different mechanisms have significant roles in regulating P sorption by sediments in a southeastern Coastal Plain in‐stream wetland.
Persistence of Fermentative Process to Phenolic Toxicity in Groundwater
Authors: Wu Youxian , Lerner David N. , Banwart Steven A. , Thornton Steven F. , Pickup Roger W. 
Published: October 2006

ABSTRACTThe fermentation process is an important component in the biodegradation of organic compounds in natural and contaminated systems. Comparing with terminal electron‐accepting processes (TEAPs), however, research on fermentation processes has to some extent been ignored in the past decades, particularly on the persistence of fermentation process in the presence of toxic organic pollutants. Both field and laboratory studies, presented here, showed that microbial processes in a groundwater‐based system exhibited a differential inhibitory response to toxicity of phenolic compounds from coal tar distillation, thus resulting in the accumulation of volatile fatty acids (VFAs) and hydrogen. This indicated that fermentation processes could be more resistant to phenol toxicity than the subsequent TEAPs such as methanogenesis and sulfate reduction, thus providing us with more options for enhancing bioremediation processes.
Degree of Phosphorus Saturation Thresholds in Manure‐Amended Soils of Alberta
Authors: Casson Janna P. , Bennett D. Rodney , Nolan Sheilah C. , Olson Barry M. , Ontkean Gerald R. 
Published: October 2006

ABSTRACTThe risk of P losses from agricultural land to surface and ground water generally increases as the degree of soil P saturation increases. A single‐point soil P sorption index (PSI) was validated with adsorption isotherm data for determination of the P sorption status of Alberta soils. Soil P thresholds (change points) were then examined for two agricultural soils after eight annual applications of different rates of cattle manure and for three agricultural soils after one application of different rates of cattle manure. Linear relationships were found between soil‐test P (STP) levels up to 1000 mg kg−1and desorbed P in the five Alberta soils. Weak linear relationships were also found between STP and runoff dissolved reactive phosphorus (DRP) in three of these soils. Change points for the degree of P saturation (DPS) were detected in four of the five soils at 3 to 44% for water‐extractable P (WEP) and at 11 to 51% for CaCl2–extractable P (CaCl2–P). Change points were not found for DPS or runoff DRP. Overall DPS thresholds for the five soils combined were 27% for WEP and 44% for CaCl2–P at a critical desorbable‐P value of 1 mg L−1The corresponding STP levels (44 mg kg−1for WEP and 71 mg kg−1for CaCl2–P) are similar to agronomic thresholds for crops grown on Alberta soils. Soluble P losses in overland flow and leaching may be greater in soils with DPS values that exceed these thresholds than in soils with lower DPS values.
Nitrogen Removal in Valley Bottom Wetlands
Authors: Montreuil Olivier , Merot Philippe 
Published: October 2006

ABSTRACTAlthough the reduction of nutrient loading between uplands and streams is sometimes considered evidence of the effect of wetlands acting as buffer zones, the influence of valley bottom wetlands (VBWs) on NO3− loading has seldom been assessed at the catchment scale. The objective of this study was to quantify the impact of VBWs on NO3− concentrations in streams in the Brittany region of France. We analyzed the spatial variation in NO3–N concentrations in 18 headwater catchments located in a 400‐km2 basin, with varying topographic, climatic, and agricultural intensity conditions. Approximately every 10 d, water was sampled during the high flow season. We investigated the relationships between the mean NO3− concentration and different characteristics of the catchments: (i) the amount of effective rainfall, i.e., the combined effect of precipitation and actual evapotranspiration on discharge and chemical dilution, (ii) the intensity of farming, i.e., the area used for farming in the catchments and the surplus of the agricultural N budget, and (iii) the relative area of VBWs. Although the first two characteristics were the main factors controlling N concentration variability, a step‐by‐step regression allowed us to attribute a significant part of the NO3− concentration decrease to the increase of VBW area in each catchment. For an increase of VBW area from 11 to 16%, the NO3–N concentration decreased from 5.3 to 4.2 mg L−1 Therefore in this basin, VBWs reduced the NO3− concentrations in streams with sources in agricultural fields by 30%. This work demonstrates the contribution of natural VBWs to NO3− removal at the catchment scale compared to other sources of variation, which is a current need for integrating water quality criteria into wetland management.
Soil Profile Distribution of Phosphorus and Other Nutrients following Wetland Conversion to Beef Cattle Pasture
Authors: Sigua Gilbert C. , Kang Woo‐Jun , Coleman Sam W. 
Published: October 2006

ABSTRACTLargely influenced by the passage of the Swamp Land Act of 1849, many wetlands were lost in the coastal plain region of the southeastern United States, primarily as a result of drainage for agricultural activities. To better understand the chemical response of soils during wetland conversion, soil core samples were collected from the converted beef cattle pastures and from the natural wetland at Plant City, FL in the summers of 2002 and 2003. Data collected from the natural wetland sites were used as reference data to detect potential changes in soil properties associated with the conversion of wetlands to improved beef cattle (Bos taurus) pastures from 1940 to 2003. The average concentration of total phosphorus (TP) in pasture soils (284 mg kg−1) was significantly (p ≤ 0.001) lower than its levels in natural wetland soils (688 mg kg−1). Compared with the adjoining natural wetlands, the beef cattle pasture soils, 63 yr after being drained exhibited: (1) a decrease in TOC (−172 g kg−1), TN (−10 g kg−1), K (−0.7 mg kg−1), and Al (−130 mg kg−1); (2) an increase in soil pH (+1.8), Ca (+88 mg kg−1), Mg (+7.5 mg kg−1), Mn (+0.3 mg kg−1), and Fe (+6.9 mg kg−1); and (3) no significant change in Na, Zn, and Cu. Wetland soils had higher concentrations (mg kg−1) of Al‐P (435), CaMg‐P (42), FeMn‐P (43), and Org‐P (162) than those of 172, 11, 11, and 84 mg kg−1, respectively, found in the pasture soils. The levels of water‐soluble P and KCl‐bound P were comparable between wetland and pasture soils in 2003. Results of this study therefore suggest that wetland conversion to beef cattle pastures did not function as a source of nutrients, especially P and N, even with manure and urine additions due to the presence of grazing cattle.
Characterization of Phosphorus Species in Biosolids and Manures Using XANES Spectroscopy
Authors: Shober Amy L. , Hesterberg Dean L. , Sims J. Thomas , Gardner Sheila 
Published: October 2006

ABSTRACTIdentification of the chemical P species in biosolids or manures will improve our understanding of the long‐term potential for P loss when these materials are land applied. The objectives of this study were to determine the P species in dairy manures, poultry litters, and biosolids using X‐ray absorption near‐edge structure (XANES) spectroscopy and to determine if chemical fractionation techniques can provide useful information when interpreted based on the results of more definitive P speciation studies. Our XANES fitting results indicated that the predominant forms of P in organic P sources included hydroxylapatite, PO4 sorbed to Al hydroxides, and phytic acid in lime‐stabilized biosolids and manures; hydroxylapatite, PO4 sorbed on ferrihydrite, and phytic acid in lime‐ and Fe‐treated biosolids; and PO4 sorbed on ferrihydrite, hydroxylapatite, β‐tricalcium phosphate (β‐TCP), and often PO4 sorbed to Al hydroxides in Fe‐treated and digested biosolids. Strong relationships existed between the proportions of XANES PO4 sorbed to Al hydroxides and NH4Cl‐ + NH4F‐extractable P, XANES PO4 sorbed to ferrihydrite + phytic acid and NaOH‐extractable P, and XANES hydroxylapatite + β‐TCP and dithionite–citrate–bicarbonate (DCB)‐ + H2SO4‐extractable P (r2 = 0.67 [P = 0.01], 0.78 [P = 0.01], and 0.89 [P = 0.001], respectively). Our XANES fitting results can be used to make predictions about long‐term solubility of P when biosolids and manures are land applied. Fractionation techniques indicate that there are differences in the forms of P in these materials but should be interpreted based on P speciation data obtained using more advanced analytical tools.