bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Phytase Addition to Poultry Diets on Phosphorus Forms and Solubility in Litters and Amended Soils
Authors: Maguire R. O. , Sims J. T. , Saylor W. W. , Turner B. L. , Angel R. , Applegate T. J. 
Published: June 2010

ABSTRACTDiet modification to decrease phosphorus (P) concentration in animal feeds and manures can reduce surpluses of manure P in areas of intensive animal production. We generated turkey and broiler litters from two and three flock trials, respectively, using diets that ranged from “high” to “low” in non‐phytate phosphorus (NPP) and some of which contained feed additives such as phytase. Phosphorus forms in selected litters were analyzed by sequential chemical fractionation and solution 31P nuclear magnetic resonance (NMR) spectroscopy. Selected litters were also incubated with four contrasting soils. Reducing dietary NPP and using phytase decreased total P in litters by up to 38%. Water‐soluble phosphorus (WSP) in litters was decreased 21 to 44% by feeding NPP closer to animal requirement, but was not affected by phytase addition. Solution 31P NMR spectroscopy showed that feeding NPP closer to requirement decreased orthophosphate in litters by an average of 38% and that adding phytase to feed did not increase the concentration of orthophosphate in litters. Phytase also decreased phytate P in litters by 25 to 38%, demonstrating that it increases phytate P hydrolysis. Incorporation of litters with soils at the same total P rate increased WSP in soils relative to the control; this increase was correlated to soluble P added with litters at 5 d, but not by 29 d. Changes in soil Mehlich‐3 phosphorus (M3‐P) were related to total P added in litter, rather than soluble P. We conclude that feeding NPP closer to requirement and using feed additives such as phytase decrease total P concentrations in litters, while having little effect on P solubility in litters and amended soils.
Phosphorus Composition of Manure from Swine Fed Low‐Phytate Grains
Authors: Leytem April B. , Turner Benjamin L. , Thacker P. A. 
Published: June 2010

ABSTRACTIncluding low‐phytic‐acid grains in swine diets can reduce P concentrations in manure, but the influence on manure P composition is relatively unknown. To address this we analyzed manure from swine fed one of four barley (Hordeum vulgare L.) varieties. The barley types consisted of wild‐type barley (CDC bold, normal barley diet) and three low‐phytic‐acid mutant barleys that contained similar amounts of total P but less phytic acid. The phytic acid concentrations in the mutant barleys were reduced by 32% (M422), 59% (M635), and 97% (M955) compared with that in the wild‐type barley, respectively. Phosphorus concentrations were approximately one‐third less in manures from animals fed low‐phytic‐acid barleys compared with those fed the wild‐type variety. Phytic acid constituted up to 55% of the P in feed, but only trace concentrations were detected in NaOH–EDTA extracts of all manures by solution 31P nuclear magnetic resonance (NMR) spectroscopy. Phosphate was the major P fraction in the manures (86–94% extracted P), with small concentrations of pyrophosphate and simple phosphate monoesters also present. The latter originated mainly from the hydrolysis of phospholipids during extraction and analysis. These results suggest that phytic acid is hydrolyzed in swine, possibly in the hind gut by intestinal microflora before being excreted in feces, even though the animals have little phytase activity in the gut and derive little nutritional benefit from phytate P. We conclude that feeding low‐phytic‐acid grains reduces total manure P concentrations and the manure P is no more soluble than P generated from normal barley diets.
Sustainable Land Application
Authors: O'Connor G. A. , Elliott H. A. , Basta N. T. , Bastian R. K. , Pierzynski G. M. , Sims R. C. , Smith J. E. 
Published: June 2010

ABSTRACTMan has land‐applied societal nonhazardous wastes for centuries as a means of disposal and to improve the soil via the recycling of nutrients and the addition of organic matter. Nonhazardous wastes include a vast array of materials, including manures, biosolids, composts, wastewater effluents, food‐processing wastes, industrial by‐products; these are collectively referred to herein as residuals. Because of economic restraints and environmental concerns about land‐filling and incineration, interest in land application continues to grow. A major lesson that has been learned, however, is that the traditional definition of land application that emphasizes applying residuals to land in a manner that protects human and animal health, safeguards soil and water resources, and maintains long‐term ecosystem quality is incomplete unless the earning of public trust in the practices is included. This overview provides an introduction to a subset of papers and posters presented at the conference, “Sustainable Land Application,” held in Orlando, FL, in January 2004. The USEPA, USDA, and multiple national and state organizations with interest in, and/or responsibilities for, ensuring the sustainability of the practice sponsored the conference. The overriding conference objectives were to highlight significant developments in land treatment theory and practice, and to identify future research needs to address critical gaps in the knowledge base that must be addressed to ensure sustainable land application of residuals.
Beneficial Reuse and Sustainability: The Fate of Organic Compounds in Land‐Applied Waste
Authors: Overcash Michael , Sims Ronald C. , Sims Judith L. , Nieman J. Karl C. 
Published: June 2010

ABSTRACTLand application systems, also referred to as beneficial reuse systems, are engineered systems that have defined and permitted application areas based on site and waste characteristics to determine the land area size requirement. These terrestrial systems have orders of magnitude greater microbial capability and residence time to achieve decomposition and assimilation compared with aquatic systems. In this paper we focus on current information and information needs related to terrestrial fate pathways in land treatment systems. Attention is given to conventional organic chemicals as well as new estrogenic and pharmaceutical chemicals of commerce. Specific terrestrial fate pathways addressed include: decomposition, bound residue formation, leaching, runoff, and crop uptake. Molecular decomposition and formation of bound residues provide the basis for the design and regulation of land treatment systems. These mechanisms allow for assimilation of wastes and nondegradation of the environment and accomplish the goal of sustainable land use. Bound residues that are biologically produced are relatively immobile, degrade at rates similar to natural soil materials, and should present a significantly reduced risk to the environment as opposed to parent contaminants. With regard to leaching and runoff pathways, no comprehensive summary or mathematical model of organic chemical migration from land treatment systems has been developed. For the crop uptake pathway, a critical need exists to develop information for nonagricultural chemicals and to address full‐scale performance and monitoring at more land application sites. The limited technology choices for treatment of biosolids, liquids, and other wastes implies that acceptance of some risks and occurrence of some benefits will continue to characterize land application practices that contribute directly to the goal of beneficial reuse and sustainability.
Processes for Managing Pathogens
Authors: Godfree Alan , Farrell Joseph 
Published: June 2010

ABSTRACTWastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post‐application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.
The Evolving Science of Chemical Risk Assessment for Land‐Applied Biosolids
Authors: Schoof Rosalind A. , Houkal Dana 
Published: June 2010

ABSTRACTBiosolids, effluents, and manures are widely applied to agricultural land and other land with varying degrees of pretreatment or control. Regulations governing land application of biosolids take several broad forms in different countries, including limitations based on rates that do not lead to increases in background chemical concentrations or risk assessment approaches such as those used in the United States. Risk assessment is a process that is inherently limited by currently available information and practices, and consequently, risk‐based land application limits must be reevaluated periodically. For complex mixtures such as biosolids, three principal categories of information will be affected by changing practices and scientific advances: (i) chemical constituents present in the material, (ii) the nature of expected exposures, and (iii) toxicity of the chemical constituents. New analytical methods and lower detection limits will affect chemical identification in wastes. Approaches to exposure assessment, such as increasing emphasis on probabilistic analyses, will continue to evolve, and exposure assumptions will change as new studies provide better data on factors such as soil ingestion, plant uptake of chemicals, and bioavailability of chemicals in soil. Similarly, toxicity assessments will be updated as new studies are conducted. The evolving science over the past decade is illustrated by comparing approaches used by the USEPA to assess human health and ecological risks for the Part 503 rule compared with the more recent evaluation of dioxins and related compounds in biosolids. While risks of chemicals in land‐applied biosolids and other residuals need to be periodically reevaluated, such reevaluations may take forms other than full risk assessments.
Atmospheric Supply of Trace Elements Studied by Peat Samples from Ombrotrophic Bogs
Authors: Steinnes E. , Hvatum O. Ø. , B⊘lviken B. , Varskog P. 
Published: June 2010

ABSTRACTConcentrations of Fe and 12 trace elements in peat from ombrotrophic bogs were used to estimate the atmospheric deposition of these elements on a temporal and spatial scale. Peat samples were collected at 21 different sites in Norway encompassing large geographical differences in marine influence and air pollution. The study demonstrates that surface peat is an excellent medium to study geographical differences in heavy metal deposition, provided that effects of the surface plant cover are properly considered. Long‐range atmospheric transport of pollutants is the main source for As, Cd, Pb, Sb, and Zn, and to a lesser extent for Cu and Se. Biogenic emissions from the ocean appear to be the main source of Se to the peat. The metals Co, Cr, Fe, and Ni are mainly associated with windblown local soil dust. Surface enrichment of Mn, and in part Zn, is mainly caused by nutrient circulation between the surface peat and vascular plants growing on it. Deposition of marine salts appears to be the main reason for lower Mn concentrations in the peat near the coast.
Fracture‐Controlled Nitrate and Atrazine Transport in Four Iowa Till Units
Authors: Helmke Martin F. , Simpkins William W. , Horton Robert 
Published: June 2010

ABSTRACTFractures in till may provide pathways for agricultural chemicals to contaminate aquifers and surface waters. This study was conducted to quantify the influence of fractures on solute fate and transport using three conservative and two nonconservative tracers. The conservative tracers were potassium bromide (KBr), pentafluorobenzoic acid (PFBA), and 1,4‐piperazinediethanesulfonic acid disodium salt (PIPES); the nonconservative tracers were nitrate and atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine]. Three sites in Iowa were investigated, including four late Wisconsinan and Pre‐Illinoian tills. Laboratory tracer experiments were conducted using eight large (0.4–0.45 m long by 0.43 m in diameter), undisturbed columns of till collected from depths of 1 to 28 m. The tills were densely fractured, with fracture spacing ranging from 3.8 to 10.4 cm. First arrival velocities of Br− ranged from 0.004 to 64.8 m d−1, 10 to 100 times faster than predicted for unfractured media. Nitrate behaved as a conservative tracer in weathered till columns, but degraded during experiments using deeper tills. Sorption caused retardation of atrazine in the shallowest four columns. Atrazine degradation occurred in deeper columns as demonstrated by deviations between atrazine and the conservative tracers. Mobile–immobile model (MIM) simulations estimated first‐order exchange coefficients (α) ranging from 1 × 10−8 to 1.7 × 10−2 s−1, sorption coefficients (Kd) for atrazine ranging from 2.6 × 10−5 to 1 × 10−3 m3 kg−1, and degradation half‐lives ranging from 0.24 to 67 d (nitrate) and 1.6 to 277 d (atrazine). This study suggests that aquifers and surface waters associated with thin, fractured till units may be vulnerable to contamination, yet deeper aquifers may be protected by these materials due to increased residence times provided by matrix diffusion.
A Laboratory Study of Bacteria‐Facilitated Cadmium Transport in Alluvial Gravel Aquifer Media
Authors: Pang L. , Close M. E. , Noonan M. J. , Flintoft M. J. , van den Brink P. 
Published: June 2010

ABSTRACTColloids, including bacteria, can dramatically accelerate the transport of heavy metals in ground water. Batch and column experiments were conducted to investigate adsorption of cadmium (Cd) onto Bacillus subtilis spores or Escherichia coli vegetative cells and Cd transport in alluvial gravel aquifer media in the presence of these bacteria. Results of the batch experiments showed that adsorption of Cd onto the bacteria was (i) positively related to solution pH, bacterial concentration, and negative surface charge, but inversely related to Cd concentration and (ii) a rate‐limited nonlinear process, but adsorption onto E. coli was much less. For column influent Cd concentrations of about 4 mg/L and bacterial concentrations of ≥105 colony‐forming units (cfu)/mL, there was a significant increase in total Cd effluent concentrations. In comparison with controls that did not have bacteria‐facilitated transport, Cd traveled 17 to 20 times faster when it traveled with mobile bacteria. However, Cd traveled mostly 2 to 3 times slower during the desorption phase under the influence of bacteria retained in the column. The difference between total and dissolved Cd concentrations was significant during Cd cotransport with B. subtilis spores, but this concentration difference was very small during Cd cotransport with E. coli, suggesting an adsorption‐dominant mechanism during Cd cotransport with the spores and the possibility of Cd chelation by the dissolved membrane vesicles secreted from E. coli cell walls. Bacteria‐facilitated transport of heavy metals may pose a threat to ground water quality in sites such as landfills and following land disposal of industrial and domestic effluent and sludge.
Effects of Sedimentation on Soil Nutrient Dynamics in Riparian Forests
Authors: Lockaby B. G. , Governo R. , Schilling E. , Cavalcanti G. , Hartsfield C. 
Published: June 2010

ABSTRACTThe influence of sedimentation rates on biogeochemistry of riparian forests was studied near ephemeral streams at Fort Benning, GA. Upper reaches of seven ephemeral streams had received varying rates of sedimentation stemming from erosion along unpaved roadways at the military installation. Two reference catchments were also included in the study. Decomposition of foliar litter, microbial C and N, N mineralization, and arthropod populations were compared within and among catchments. Rates of sedimentation over the past 25 yr ranged from 0 in references to 4.0 cm yr−1Decomposition rates declined exponentially with sedimentation rates as low as 0.20 to 0.32 cm yr−1and appeared to reach an equilibrium at a sedimentation rate of 0.5 cm yr−1Nitrogen mineralization and microbial C and N followed the same trend. Sedimentation had no discernible effect on arthropod populations. These data suggest that biogeochemical cycles may be altered by sedimentation rates that commonly occur in some floodplain forests.
Assessment of Denitrification Gaseous End‐Products in the Soil Profile under Two Water Table Management Practices Using Repeated Measures Analysis
Authors: Elmi Abdirashid A. , Astatkie Tess , Madramootoo Chandra , Gordon Robert , Burton David 
Published: June 2010

ABSTRACTThe denitrification process and nitrous oxide (N2O) production in the soil profile are poorly documented because most research into denitrification has concentrated on the upper soil layer (0–0.15 m). This study, undertaken during the 1999 and 2000 growing seasons, was designed to examine the effects of water table management (WTM), nitrogen (N) application rate, and depth (0.15, 0.30, and 0.45 m) on soil denitrification end‐products (N2O and N2) from a corn (Zea mays L.) field. Water table management treatments were free drainage (FD) with open drains and subirrigation (SI) with a target water table depth of 0.6 m. Fertility treatments (ammonium nitrate) were 120 kg N ha−1 (N120) and 200 kg N ha−1 (N200). During both growing seasons greater denitrification rates were measured in SI than in FD, particularly in the surface soil (0–0.15 m) and at the intermediate (0.15–0.30 m) soil depths under N200 treatment. Greater denitrification rates under the SI treatment, however, were not accompanied with greater N2O production. The decrease in N2O production under SI was probably caused by a more complete reduction of N2O to N2, which resulted in lower N2O to (N2O + N2) ratios. Denitrification rate, N2O production and N2O to (N2O + N2) ratios were only minimally affected by N treatments, irrespective of sampling date and soil depth. Overall, half of the denitrification occurred at the 0.15‐ to 0.30‐ and 0.30‐ to 0.45‐m soil layers, and under SI, regardless of fertility treatment level. Consequently, sampling of the 0‐ to 0.15‐m soil layer alone may not give an accurate estimation of denitrification losses under SI practice.
Copper Availability in Seven Israeli Soils Incubated with and without Biosolids
Authors: Oliver I. W. , Hass A. , Merrington G. , Fine P. , McLaughlin M. J. 
Published: June 2010

ABSTRACTLand application is becoming a preferred option for disposal of sewage sludge (biosolids) from wastewater treatment plants. However, it creates potential risks due to the heavy metal contents of these materials, with copper (Cu) being of chief concern. The long‐term fate of biosolid metals applied to agricultural soils is not well understood, particularly in the soils of the Middle East. This investigation was conducted to determine whether the availability of Cu changes with time in biosolid‐amended and nonamended soils from Israel. Seven soils, typifying the span of properties and formation environments encountered in Israel, were incubated with and without biosolids for 7 yr, and changes in organic carbon (OC) content and labile Cu concentration were determined. Isotopic exchange techniques, using64Cu, and ion activity measurements, using a Cu2+ion selective electrode, revealed that the available Cu concentration remained relatively low and stable over the 7‐yr incubation. This was despite substantial reductions in OC. This study shows that, with regard to Cu, application of such biosolids to these soils at rates of up to 250 Mg ha−1does not pose a threat to the environment in the short to medium term.
Characterization of the Pesticide Chlordane in Estuarine River Sediments
Authors: Ouyang Y. , Ou L.‐T. , Sigua G. C. 
Published: June 2010

ABSTRACTSediments are increasingly recognized as both carrier and potential source of contaminants in aquatic environments. This study investigated the characteristics and spatial distribution of total chlordane and its three most abundant compounds, including α‐chlordane, γ‐chlordane, and trans‐nonachlor, in sediments from the Cedar and Ortega rivers, Florida, USA, using geographic information system (GIS)‐based kriging analyses and field measurements. Kriging analysis showed that two areas, one from the Cedar River area and the other from the northern end of the Ortega River area, were contaminated. The maximum concentrations of total chlordane, γ‐chlordane, α‐chlordane, and trans‐nonachlor in the sediments were, respectively, 101.8, 20.1, 26.3, and 19.2 μg/kg. A plot of total organic carbon (TOC)‐normalized chlordane concentrations showed that effects of grain size on sediment chlordane contamination were negligible. A principal axis analysis further revealed that a linear correlation existed between α‐chlordane and total chlordane as well as between γ‐chlordane and total chlordane, whereas no correlation existed between trans‐nonachlor and total chlordane. Comparison of total chlordane concentration with Florida Sediment Assessment Guidelines showed that the Cedar River and the northern end of the Ortega River had total chlordane concentrations above the probable effect level (4.79 μg/kg), which could pose a potential risk to aquatic life.