bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preferential Flow of Bromide, Bentazon, and Imidacloprid in a Dutch Clay Soil
Authors: Júnior Rômulo Penna Scorza , Smelt Johan H. , Boesten Jos J. T. I. , Hendriks Rob F. A. , van der Zee Sjoerd E. A. T. M. 
Published: June 2010

ABSTRACTLeaching to ground water and tile drains are important parts of the environmental assessment of pesticides. The aims of the present study were to (i) assess the significance of preferential flow for pesticide leaching under realistic worst‐case conditions for Dutch agriculture (soil profile with thick clay layer and high rainfall) and (ii) collect a high‐quality data set that is suitable for testing pesticide leaching models. The movement of water, bromide, and the pesticides bentazon [3‐isopropyl‐1H‐2, 1,3‐benzothiadiazine‐4(3H)‐one‐2,2‐dioxide] and imidacloprid [1‐[(6‐chloro‐3‐pyridinyl)‐methyl]‐N‐nitro‐2‐imidazolidinimine] was monitored in a clay soil for about 1 yr. The 1.2‐ha field was located in the central part of the Netherlands (51°53′ N, 5°43′ E). The soil was a Eutric Fluvisol cropped with winter wheat (Triticum aestivum L.). Tile drains were present at a 0.8‐ to 0.9‐m depth and the ground water level fluctuated between a 0.5‐ and 2‐m depth. All chemicals were applied in spring. None of the soil concentration profiles showed bimodal concentration distributions. However, for each substance the highest concentration in drain water was found in the first drainage event after its application, which indicates preferential flow. This preferential flow is probably caused by permanent macropores that were present in the 0.3‐ to 1.0‐m layer. At the time of the first drainage event, the drain water concentration of each substance was about an order of magnitude higher than its ground water concentration. Thus, the flux concentrations in drain water proved to be a more sensitive detector of preferential flow than the resident concentrations in the soil profile and the ground water.
Phosphorus Speciation in Manure‐Amended Alkaline Soils
Authors: Hansen Jeremy C. , Cade‐Menun Barbara J. , Strawn Daniel G. 
Published: June 2010

ABSTRACTTwo common manure storage practices are stockpiles and lagoons. The manure from stockpiles is applied to soils in solid form, while lagoon manure is applied as a liquid. Soil amendment with manure in any form introduces a significant amount of phosphorus (P) that exists in both organic and inorganic forms. However, little is known about P speciation in manure stored under different conditions, or the subsequent forms when applied to soils. We used solution 31P nuclear magnetic resonance (NMR) spectroscopy and conventional P fractionation and speciation methods to investigate P forms in dairy manure and liquid lagoon manure, and to study how long‐term amendment with these manures influenced surface and subsurface soil P speciation. Our results show that the P forms in solid and lagoon manure are similar. About 30% of the total P was organic, mostly as orthophosphate monoesters. On a dry weight basis, total P was much higher in the solid manure. In the manure‐amended soils the total P concentrations of the surface soils were similar, regardless of manure type. Total P in the subsurface soil was greater in the lagoon‐manure‐amended soil than the solid‐manure‐amended subsurface soil. However, the fraction of organic P was greater in the subsurface of the solid‐manure‐amended soil. The NMR results indicate that the majority of organic P in the soils is phytic acid, which is enriched in the surface soils compared with the subsurface soils. These results provide insight into P speciation and dynamics in manure‐amended soils that will further increase our understanding on how best to manage manure disposal on soils.
Phosphorus Distribution in Dairy Manures
Authors: He Zhongqi , Griffin Timothy S. , Honeycutt C. Wayne 
Published: June 2010

ABSTRACTThe chemical composition of manure P is a key factor determining its potential bioavailability and susceptibility to runoff. The distribution of P forms in 13 dairy manures was investigated with sequential fractionation coupled with orthophosphate‐releasing enzymatic hydrolysis. Among the 13 dairy manures, manure total P varied between 4100 and 18300 mg kg−1 dry matter (DM). Water‐extractable P was the largest fraction, with inorganic phosphorus (Pi) accounting for 12 to 44% of manure total P (1400–6800 mg kg−1) and organic phosphorus (Po) for 2 to 23% (130–1660 mg kg−1), respectively. In the NaHCO3 fraction, Pi varied between 740 and 4200 mg P kg−1 DM (4–44% of total manure P), and Po varied between 340 and 1550 mg P kg−1 DM (2–27% of total manure P). In the NaOH fraction, Pi fluctuated around 200 mg P kg−1 DM, and Po ranged from 130 to 630 mg P kg−1 DM. Of the enzymatically hydrolyzable Po in the three fractions, phytate‐like P dominated, measuring 26 to 605 mg kg−1 DM, whereas monoester P and DNA‐like P were relatively low and less variable. Although concentrations of various P forms varied considerably, significant correlations between manure total P and certain P forms were observed. For example, H2O‐extracted Pi was correlated with total manure P (R2 = 0.62), and so was NaOH‐extracted Po (R2 = 0.81). Data also show that the amount of P released by a single extraction with sodium acetate (100 mM, pH 5.0) was equivalent to the sum of P in all three fractions (H2O‐, NaHCO3–, and NaOH‐extractable P). Thus, a single extraction by sodium acetate buffer could provide an efficient evaluation of plant‐available P in animal manure, while the sequential fractionation approach provides more detailed characterization of manure P.
Analysis of Volatile and Semivolatile Hydrocarbons Recovered from Steam‐Classified Municipal Solid Waste
Authors: Leahy Joseph G. , Carrington Thomas E. , Eley Michael H. 
Published: June 2010

ABSTRACTHazardous household wastes comprise a significant proportion of municipal solid waste (MSW), and therefore serve as the source of many toxic or carcinogenic organic chemicals that are released in the environment through landfill gases or leachates. In the present study, we demonstrate the utility of the steam classification process in removing hazardous semivolatile organic compounds (SVOCs) and volatile organic compounds (VOCs) from MSW. Steam classification is a patented technology that involves the treatment of MSW with steam under pressure to yield a cellulosic biomass product that can be used as a fuel or in building materials. The SVOCs and VOCs from the waste off‐gases are collected in the steam condensate and in an effluent charcoal filter. The results of this study show that at least two SVOCs and at least 17 VOCs can be removed from the waste. The most commonly identified compounds were diethylphthalate, styrene, 1,4‐dichlorobenzene, and toluene in the condensates, and styrene, 1,1,1‐trichloroethane, and toluene in the charcoal filters. On a weight basis, aromatic hydrocarbons were primarily recovered in the condensates, while the chloroaliphatic hydrocarbons were recovered almost exclusively from the charcoal filters. 1,3‐Dichlorobenzene, 1,4‐dichlorobenzene, and chloroform together comprised nearly 50% of the 4470 μg kg−1 average mass of SVOCs and VOCs recovered from about 454 kg of MSW in these experiments. Toxicity characteristic leaching procedure (TCLP) analyses showed that steam classification recovered at least 75 to 91% of tested analytes. Overall, these results suggest that steam classification represents an effective technology for a significant reduction or the removal of hazardous organics from the waste stream, and, consequently, in reducing the extent of environmental contamination associated with landfill leachates and gases.
Photodegradation of the Endocrine‐Disrupting Chemical 4‐Nonylphenol in Biosolids Applied to Soil
Authors: Xia Kang , Jeong Chang Yoon 
Published: June 2010

ABSTRACTThere is increasing concern about the environmental fate and impact of biosolids‐associated anthropogenic organic chemicals, among which 4‐nonylphenol (4‐NP) is one of the most studied chemicals. This is primarily because 4‐NP is an endocrine disruptor and has been frequently detected in environmental samples. Due to its high hydrophobicity, 4‐NP has high affinity for biosolids. Land application of 4‐NP–containing biosolids could potentially introduce large quantities of this chemical into the environment. A laboratory experiment was conducted to investigate the effect of artificial sunlight on 4‐NP degradation in biosolids applied to soil. When exposed to artificial sunlight for 30 d, the top‐5‐mm layer of biosolids showed a 55% reduction of 4‐NP, while less than 15% of the 4‐NP was degraded when the biosolids were kept in the dark. Our results indicate that sensitized photolysis reaction plays an important role in reducing the levels of 4‐NP in land‐applied biosolids. Surface application rather than soil incorporation of biosolids could be effective in reducing biosolids‐associated organic chemicals that can be degraded through photolysis reactions. However, the risks of animal ingestion, foliar deposition, and runoff should also be evaluated when biosolids are applied on the soil surface.
Enzyme Activities and Arylsulfatase Protein Content of Dust and the Soil Source: Biochemical Fingerprints?
Authors: Acosta‐Martínez V. , Zobeck T. M. 
Published: June 2010

ABSTRACTLittle is known about the potential of enzyme activities, which are sensitive to soil properties and management, for the characterization of dust properties. Enzyme activities may be among the dust properties key to identifying the soil source of dust. We generated dust (27 and 7 μm) under controlled laboratory conditions from agricultural soils (0–5 cm) with history of continuous cotton (Gossypium hirsutum L.) or cotton rotated with peanut (Arachis hypogaea L.), sorghum [Sorghum bicolor (L.) Moench], rye (Secale cereale L.), or wheat (Triticum aestivum L.) under different water management (irrigated or dryland) and tillage (conservation or conventional) systems. The 27‐ and 7‐μm dust samples showed activities of β‐glucosidase, alkaline phosphatase, and arylsulfatase, which are related to cellulose degradation and phosphorus and sulfur mineralization in soil, respectively. Dust samples generated from a loam and sandy clay loam showed higher enzyme activities compared with dust samples from a fine sandy loam. Enzyme activities of dust samples were significantly correlated to the activities of the soil source with r > 0.74 (P < 0.01). The arylsulfatase proteins contents of the soils (0.04–0.65 mg protein kg−1 soil) were lower than values reported for soils from other regions, but still dust contained arylsulfatase protein. The three enzyme activities studied, as a group, separated the dust samples due to the crop rotation or tillage practice history of the soil source. The results indicated that the enzyme activities of dust will aid in providing better characterization of dust properties and expanding our understanding of soil and air quality impacts related to wind erosion.
Changes in Soil Nitrogen and Phosphorus under Different Broiler Production Systems
Authors: Kratz Sylvia , Rogasik Jutta , Schnug Ewald 
Published: June 2010

ABSTRACTIn a field study, soils of four conventional free‐range and organic broiler runs were analyzed for N and P concentrations in the years 2000 and 2001. Zones of different use intensity by broilers were identified on the free runs and mean zonal nutrient contents were compared with each other. Intensity of use by birds and spatial distribution of soil nutrient concentrations were found to be related to each other. Fecal N input by broilers resulted in accumulation of soil mineral nitrogen (Nmin) contents down to a 90‐cm sampling depth. In highly frequented “hot spots,” plant requirement as defined by the German “N‐Basis‐Sollwert” (110 kg/ha Nmin) for grassland was exceeded in all four cases. This implies an increased environmental risk of ammonia volatilization and nitrate leaching. Fecal P input by broilers resulted in accumulation of plant‐available and thus mobile soil P (phosphorus extracted with calcium‐acetate‐lactate [PCAL] and phosphorus extracted with water [Pw]) in the most intensely used zones. In these areas, soil P contents exceeded 90 mg/kg PCAL (upper limit of soil test P defined in Germany for optimum plant yield) by as much as 217 mg/kg, which indicates an enhanced risk of P loss from the soil via runoff or leaching. The conclusion might be drawn that, with regard to nutrient loss from free‐run soils, intensive indoor production in a closed system may be more environmentally neutral than conventional free‐range or organic production. However, to put this into perspective, the scope of the environmental risk connected with spatially limited point accumulation of nutrients should be considered. Furthermore, an environmental evaluation must also account for the fate and environmental effects of the broiler litter produced inside the broiler house.
Sorption and Degradation of Alachlor and Metolachlor in Ground Water Using Green Sands
Authors: Lee Taeyoon , Benson Craig H. 
Published: June 2010

ABSTRACTReactive barriers are used for in situ treatment of contaminated ground water. Waste green sand, a by‐product of gray‐iron foundries that contains iron particles and organic carbon, was evaluated in this study as a low‐cost reactive material for treating ground water contaminated with the herbicides alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide] and metolachlor [2‐chloro‐6′‐ethyl‐N‐(2‐methoxy‐1‐methylethyl)‐o‐acetoluidide]. Batch and column tests were conducted with 11 green sands to determine transport parameters and reaction rate constants for the herbicides. Similar Fe‐normalized rate constants (KSA) were obtained from the batch and column tests. The KSA values obtained for green sand iron were also found to be comparable with or slightly higher than KSA values for Peerless iron, a common reactive medium used in reactive barriers. Partition coefficients ranging between 3.6 and 50.2 L/kg were obtained for alachlor and between 1.0 and 54.8 L/kg for metolachlor, indicating that the organic carbon and clay in green sands can significantly retard the movement of the herbicides. Partition coefficients obtained from the batch and column tests were similar (±25%), but the batch tests typically yielded higher partition coefficients for green sands exhibiting greater sorption. Calculations made using transport parameters from the column tests indicate that a 1‐m‐thick reactive barrier will result in a 10‐fold reduction in concentration of alachlor and metolachlor for seepage velocities less than 0.1 m/d provided the green sand contains at least 2% iron. This level of reduction generally is sufficient to reduce alachlor and metolachlor concentrations below maximum contaminant levels in the United States.
Kinetics of Chromate Adsorption on Goethite in the Presence of Sorbed Silicic Acid
Authors: Garman Stephanie M. , Luxton Todd P. , Eick Matthew J. 
Published: June 2010

ABSTRACTThe adsorption of chromate on mineral surfaces has received much attention due to its toxicity in natural systems. Spectroscopic studies have demonstrated that chromate forms inner‐sphere complexes on variable‐charge surfaces. However, in natural systems chromate has been observed to be fairly mobile, which has been explained by the presence of naturally occurring ligands competing with chromate for mineral surface sites. Silicic acid is a ubiquitous ligand in soil and water environments and also sorbs strongly to variable‐charge surfaces. Yet little research has examined its influence on chromate adsorption to variable‐charge surfaces such as goethite. This study examined the influence of silicic acid (0.10 and 1.0 mM) on the adsorption kinetics of chromate (0.05 and 0.10 mM) on goethite over a range of common soil pH values (4, 6, and 8). The rate and total quantity of chromate adsorption decreased in all the experiments except at a pH value of 4 and a chromate concentration of 0.05 mM The inhibition of chromate adsorption ranged from 3.1% (pH = 4, Si = 0.10 mM, chromate = 0.10 mM) to 83.3% (pH = 8, Si = 1.0 mM, chromate = 0.05 mM). The rate of chromate adsorption decreased with an increase in pH and silicic acid concentration. This was attributed to a reduction in the surface potential of goethite on silicic acid adsorption as well as a competition for surface sites. The presence of naturally occurring ligands such as silicic acid may be responsible for the enhanced mobility of chromate in natural systems and demonstrates the importance of competitive adsorption for evaluating the mobility of trace elements.
Degradation of N,N′‐Dibutylurea (DBU) in Soils Treated with only DBU and DBU‐Fortified Benlate Fungicides
Authors: Lee Linda S. , Sassman Stephen A. , Bischoff Marianne , Turco Ronald F. 
Published: June 2010

ABSTRACTN,N′‐dibutylurea (DBU) is a breakdown product of benomyl [methyl 1‐(butylcarbamoyl)‐2‐benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed to cause crop damage after the use of Benlate 50 DF fungicide (DuPont, Wilmington, DE). Our research focused on DBU persistence after application into soil. We assessed DBU persistence on direct application of DBU (carbonyl–14C) at two concentrations (0.08 and 0.8 μg DBU kg−1) to seven soils and two potting mixes in soil microcosms incubated at various combinations of soil water potential (−0.03 or −0.1 MPa) and temperature (23, 33, 44°C). For two soils at a subset of treatment variables we assessed DBU persistence in the presence of Benlate DF and SP fungicide formulations. Parent compounds, metabolites, and 14CO2 were tracked using chromatographic analysis with radioassay and UV detection, liquid scintillation counting, and post‐extraction oxidation of the soil. DBU degradation was primarily microbial and for most soil–treatment combinations, half‐lives were less than 2 wk. DBU degradation was retarded at the lower soil water potential and enhanced at 33°C. In the presence of the formulation, DBU degradation was slower for one soil type. The longest half‐life observed in any case was less than 7 wk; therefore, long‐term persistence of DBU applied to soils through a Benlate application is very unlikely.
Effects of Aeration on Water Quality from Septic System Leachfields
Authors: Potts David A. , Görres Josef H. , Nicosia Erika L. , Amador José A. 
Published: June 2010

ABSTRACTWe conducted a pilot‐scale study at a research facility in southeastern Connecticut to assess the effects of leachfield aeration on removal of nutrients and pathogens from septic system effluent. Treatments consisted of lysimeters periodically aerated to maintain a headspace O2 concentration of 0.209 mol mol−1 (AIR) or vented to an adjacent leachfield trench (LEACH) and were replicated three times. All lysimeters were dosed with effluent from a septic tank for 24 mo at a rate of 12 cm d−1 and subsequently for 2 mo at 4 cm d−1 LEACH lysimeters had developed a clogging mat, or biomat, 20 mo before the beginning of our study. The level of aeration in the AIR treatment was held constant regardless of loading rate. No conventional biomat developed in the AIR treatment, whereas a biomat was present in the LEACH lysimeters. The headspace of LEACH lysimeters was considerably depleted in O2 and enriched in CH4, CO2, and H2S relative to AIR lysimeters. Drainage water from AIR lysimeters was saturated with O2 and had significantly lower pH, five‐day biological oxygen demand (BOD5), and ammonium, and higher levels of nitrate and sulfate than LEACH lysimeters regardless of dosing rate. By contrast, significantly lower levels of total N and fecal coliform bacteria were observed in AIR than in LEACH lysimeters only at the higher dosing rate. No significant differences in total P removal were observed. Our results suggest that aeration may improve the removal of nitrogen, BOD5, and fecal coliforms in leachfield soil, even in the absence of a biomat.
Seawater Neutralization of Alkaline Bauxite Residue and Implications for Revegetation
Authors: Menzies N. W. , Fulton I. M. , Morrell W. J. 
Published: June 2010

ABSTRACTReaction of bauxite residue with seawater results in neutralization of alkalinity through precipitation of Mg‐, Ca‐, and Al‐hydroxide and carbonate minerals. In batch studies, the initial pH neutralization reaction was rapid (<5 min), with further reaction continuing to reduce pH for several weeks. Reaction with seawater produced a residue pH of 8 to 8.5. Laboratory leaching column studies were undertaken to provide information on seawater neutralization of the coarse‐textured fraction of the waste, residue sand (RS), under conditions comparable with those that might be applied in the field. An 0.80‐m‐deep column of RS was neutralized by the application of the equivalent of 2‐m depth of seawater. In addition to lowering the pH and Na content of the residue, seawater neutralization resulted in the addition of substantial amounts of the plant nutrients Ca, Mg, and K to the profile. Similar results were also obtained from a field‐scale assessment of neutralization. However, the accumulation of precipitate, consisting of hydrotalcite, aragonite, and pyroaurite, in the drainage system may preclude the use of in situ seawater neutralization as a routine rehabilitation practice. Following seawater neutralization, RS remains too saline to support plant growth and would require fresh water leaching before revegetation.
Water‐Soluble and Solid‐State Speciation of Phosphorus in Stabilized Sewage Sludge
Authors: Huang Xiao‐Lan , Shenker Moshe 
Published: June 2010

ABSTRACTThree chemicals, ferrous sulfate (Fe‐sul), calcium oxide (CaO), and aluminum sulfate (alum), were used to stabilize phosphorus (P) in fresh, anaerobically digested sewage sludge (FSS). The chemically stabilized sludge materials and biosolids compost (BSC) were compared with the FSS with respect to water‐soluble phosphorus (WSP) content in its inorganic (WSPi) and organic (WSPo) forms as well as water‐soluble organic carbon (DOC). Solid‐state P speciation was further probed by X‐ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy‐dispersive X‐ray elemental spectrometry (EDXS). Water‐soluble P was effectively controlled by a wide range of Fe‐sul or CaO additions to the sludge (Ca to P ratio = 3.47–17.72, Fe to P ratio = 1.01–16.53), but by only a narrow range (Al to P ratio = 1.04–2.87) of alum addition. The WSP content in the BSC was also depressed, but to a lesser extent. The pH in the treated sludge ranged from 3.0 to 12.5 and served as a key factor to control P chemistry. No correlation was observed between DOC and WSPo No crystallized Ca‐P minerals were detected in the CaO‐stabilized sludge, but brushite crystallization seemed to be obtained by low addition of Fe‐sul and alum. Variscite and strengite crystallization was obtained following high addition of Fe‐sul or alum, as detected by XRD and SEM–EDXS. Adsorption of P by newly formed Fe‐hydroxide seems to play an important role in the Fe‐sul‐stabilized sludge. We concluded that administration of the tested chemicals at the proper rate can effectively reduce the hazard of P release and leaching from sludge.