bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled Effects of Treated Effluent Irrigation and Wetting–Drying Cycles on Transport of Triazines through Unsaturated Soil Columns
Authors: Seol Yongkoo , Lee Linda S. 
Published: June 2010

ABSTRACTThe physical and chemical parameters controlling the movement of atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine; 98.8%) and prometryn [N,N′‐bis(1‐methylethyl)‐6‐(methylthio)‐1,3,5‐triazine‐2,4‐diamine; 99.5%] were investigated in columns infiltrated with treated effluent under unsaturated transient conditions and subjected to drying events at 22 or 60°C followed by rewetting. Three soils varying in soil pH and texture and three solutions were used. The infiltrating solutions consisted of either a CaCl2 matrix (CC), a swine waste–derived lagoon effluent (SW), or a simulated buffer solution (SB) representative of the element composition and pH of the SW but with no dissolved organic matter. Several parameters were monitored including leachate triazine concentrations, pH, dissolved organic carbon (DOC), inorganic carbon, and flow rates. Compared with CC, application of SW and SB increased column leachate pH, enhanced dissolution of organic carbon and particle dispersion, and decreased average flow rates, which allowed for increased desorption time. The coupled effect of these processes enhanced movement of triazines in some cases, with SW generally having the greatest effect. The individual effect of increased pH was more pronounced for prometryn (pKa = 4.05) versus atrazine (pKa = 1.66), and most dramatic for the soil with the lowest initial pH. High‐temperature drying, which simulated intensive evaporation, further enhanced the dissolution of soil organic matter and the reduction in leachate flow rates with SW and SB applications; however, the net effect under the experimental conditions employed varied with soil type. Relative to low‐temperature drying, high‐temperature drying in the silty clay loam–packed columns reduced pesticide migration.
Ryegrass Cover Crop Effects on Nitrate Leaching in Spring Barley Fertilized with 15NH415NO3
Authors: Bergström Lars F. , Jokela William E. 
Published: June 2010

ABSTRACTCover crops are a management option to reduce NO3 leaching under cereal grain production. A 2‐yr field lysimeter study was established in Uppsala, Sweden, to evaluate the effect of a perennial ryegrass (Lolium perenne L.) cover crop interseeded in barley (Hordeum vulgare L.) on NO3–N leaching and availability of N to the main crop. Barley and ryegrass or barley alone were seeded in mid‐May 1992, in lysimeters (0.3‐m diam. × 1.2‐m depth) of an undisturbed, well‐drained, sandy loam soil. Fertilizer N was applied at the same time as labeled 15NH415NO3 (10 atom % 15N) at a rate of 100 kg N ha−1 In 1993, barley was reseeded in May in the lysimeters but with nonlabeled NH4NO3 and no cover crop (previous year's cover crop incorporated just prior to seeding). Barley yields and total and fertilizer N uptake in Year 1 (1992) were unaffected by cover crop. Total aboveground N uptake by the ryegrass was 28 kg ha−1 at the time of incorporation the following spring. Recovery of fertilizer‐derived N in May 1993 was about 100%; 53% in soil, 46% in barley, <2% in ryegrass, and negligible amounts in leachate. In May 1994, the corresponding figures were: 32% in soil, <3% in barley, and, again, negligible amounts in leachate. The cover crop reduced concentrations of NO3–N in the leachate considerably (<5 mg L−1, compared with 10 to 18 mg L−1 without cover crop) at most sampling times from November 1992 to April 1994, and reduced the total amount of NO3–N leached (22 compared with 8 kg ha−1).
Distribution and Movement of Sludge‐Derived Trace Metals in Selected Nigerian Soils
Authors: Mbila Monday O. , Thompson Michael L. , Mbagwu Joe S. C. , Laird David A. 
Published: June 2010

ABSTRACTUse of metal‐rich sewage sludge as soil fertilizer may result in trace‐metal contamination of soils. This study was conducted to evaluate the effects of long‐term sludge application on trace‐metal (Zn, Cu, Pb, and Ni) distribution and potential bioavailability in Nigerian soils under a tropical wet–dry climate. Total metal analyses, sequential chemical fractionation, and DTPA extractions were carried out on samples of control and sludge‐amended pedons in Nigeria (a Rhodic Kandiustult and two Rhodic Kandiustalfs from Nigeria, respectively). The sewage sludge applied to the soils contained higher levels of Zn and Cu than Pb and Ni. The control pedon contained low levels of all four metals. Soil enrichment factors (EF) were calculated for each metal in the sludge‐amended pedons. Compared with the control soil, the sludge‐amended pedons showed elevated levels of Zn and Cu, reflecting the trace‐metal composition of the sewage sludge. Zinc and Cu in the sludge‐amended soils were strongly enriched at all depths in the profile, indicating that they had moved below the zone of sludge application. The sequential extraction and DTPA analyses indicated that the sludge‐amended soils contained more readily extractable and bioavailable metal ions than the unamended soil.
Manure Phosphorus Extractability as Affected by Aluminum‐ and Iron By‐Products and Aerobic Composting
Authors: Dao Thanh H. , Sikora L. J. , Hamasaki A. , Chaney R. L. 
Published: June 2010

ABSTRACTShifts in manure phosphorus (P) chemical forms and pool sizes induced by water treatment residuals and industrial mineral by‐products are largely undefined. We conducted a manure P fractionation study to determine mechanisms of reduction of dissolved reactive phosphorus (DRP) in poultry manure upon mineral by‐product additions. The effects of composting on the P immobilization efficacy of the by‐products were determined using laboratory self‐heating composting simulators. The mineral by‐products included an aluminum‐water treatment residual (Al‐WTR) and an iron‐rich titanium‐processing by‐product. The noncomposted manure averaged 0.11 g g−1 of total P as DRP forms. The by‐products significantly reduced manure DRP, by an average of 39 and 48% in the Al‐ and the Fe‐treated manure, respectively. The by‐products also reduced the 0.5 M NH4F–extractable phosphorus (FEP) fraction. Shifts in P forms between FEP and 0.1 M NaOH–extractable phosphorus (SHEP) depended upon the Al and Fe contents of the by‐products while the combined FEP + SHEP pool remained constant. Phosphate sorption measurements supported the observations that the Fe‐rich by‐product was more effective at reducing manure DRP and enhancing the formation of SHEP forms at the expense of FEP than the Al‐WTR. Composting had no effect on the efficacy of either by‐product to reduce DRP. Potential mechanisms of enhanced P stabilization in treated manure upon composting included chemical shifts from the DRP and FEP fractions to the citrate–bicarbonate–dithionite extractable P fraction. Thus, the choice of P immobilization agents affected the stability of immobilized P forms and should be taken into consideration in developing manure processing and nutrient stabilization methods.
Leachate Chemistry of Field‐Weathered Spent Mushroom Substrate
Authors: Guo Mingxin , Chorover Jon , Rosario Rex , Fox Richard H. 
Published: June 2010

ABSTRACTPassive leaching by rainfall and snowmelt is a popular method to treat piles of spent mushroom substrate (SMS) before its reuse. During this field weathering process, leachate percolates into the underlying soils. A field study was conducted to examine the chemistry of SMS leachate and effects of infiltration. Two SMS piles were deposited (90 and 150 cm in height) over a Typic Hapludult and weathered for 24 mo. Leachate was collected biweekly using passive capillary samplers. The SMS leachate contained high concentrations of dissolved organic carbon (DOC; 0.8–11.0 g L−1), dissolved organic nitrogen (DON; 0.1–2 g L−1), and inorganic salts. The pH, electrical conductivity, and acid neutralizing capacity were 6.6 to 9.0, 21 to 66 ds m−1, and 10 to 75 mmolc L−1, respectively. Inorganic chemistry of the leachate was dominated by K+, Cl−, and SO2−4 Leachate DOC was predominantly low molecular weight (<1000 Da) organic acids. During 2 yr of weathering, the 90‐cm SMS pile released (per cubic meter of SMS) 3.0 kg of DOC, 1.6 kg of dissolved N, and 26.6 kg of inorganic salts. The 150‐cm pile released (per cubic meter of SMS) 2.8 kg of DOC, 0.7 kg of dissolved N, and 13.6 kg of inorganic salts. The 150‐cm pile retained more water and exhibited lower net nitrification compared with the 90‐cm pile. The top 90 cm of soil retained 20 to 89% of the leachate solutes. Weathering of SMS in piles of 90 cm depth or greater may adversely affect ground water quality.
Trace Element Removal from Coal Ash Leachate by a 10‐Year‐Old Constructed Wetland
Authors: Ye Z. H. , Whiting S. N. , Qian J. H. , Lytle C. M. , Lin Z.‐Q. , Terry N. 
Published: June 2010

ABSTRACTThis study investigated the ability of a 10‐yr‐old constructed wetland to treat metal‐contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. The trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0–5 cm) of the sediment profile tended to be higher than the lower layers (5–10 and 10–15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
Cesium‐134 as a Tracer to Study Particle Transport Processes within a Small Catchment with a Buffer Zone
Authors: Syversen Nina , Øygarden Lillian , Salbu Brit 
Published: June 2010

ABSTRACTThe purpose of the study is to use soil particles labeled with the radioactive tracer cesium‐134 (134Cs) as a method for studying soil erosion and sedimentation pattern within a small catchment with buffer zones. Cesium is adsorbed to soil particles, and by measuring changes in the 134Cs activity on the soil surface, erosion, sedimentation, and pathways for particles can be traced. A harrowed area was surface‐contaminated with 134CsCl, while the buffer zone was left uncontaminated. A grid net in the tilled plot and buffer zone was established for in situ measurements of the 134Cs activity after major runoff events from October 1993 to May 1996. In addition, 134Cs activity and suspended solids in runoff were followed during the events. At the end of the experiment, the vertical distribution of 134Cs in soil profiles and uptake of 134Cs in vegetation within the buffer zone were determined. At the end of the experiment, about 54% of the applied tracer remained at the soil surface. Surface soil erosion occurred relatively uniformly across the hillslope due to sheet flow. Most of the tracer was transported vertically into the soil profile, probably during the first heavy rainfall 3 wk after application when the soil was newly tilled. Sedimentation occurred in the upper part of the buffer zone. The correlation between suspended particles in runoff and 134Cs activity was good (R2 = 0.76). The study also demonstrates the benefit of utilizing 134Cs2+ tracer for investigating transport pathways for contaminated particles within a hillslope system without disturbing the surface soil system.
Herbicide and Nutrient Transport from an Irrigation District into the South Saskatchewan River
Authors: Cessna A. J. , Elliott J. A. , Tollefson L. , Nicholaichuk W. 
Published: June 2010

ABSTRACTPesticides and nutrients can be transported from treated agricultural land in irrigation runoff and thus can affect the quality of receiving waters. A 3‐yr study was carried out to assess possible detrimental effects on the downstream water quality of the South Saskatchewan River due to herbicide and plant nutrient inputs via drainage water from an irrigation district. Automated water samplers and flow monitors were used to intensively sample the drainage water and to monitor daily flows in two major drainage ditches, which drained approximately 40% of the flood‐irrigated land within the irrigation district. Over three years, there were no detectable inputs of ethalfluralin into the river and those of trifluralin were less than 0.002% of the amount applied to flood‐irrigated fields. Inputs of MCPA, bromoxynil, dicamba and mecoprop were 0.06% or less of the amounts applied, whereas that for clopyralid was 0.31%. The relatively higher input (1.4%) of 2,4‐D to the river was probably due its presence in the irrigation water. Corresponding inputs of P (as total P) and N (as nitrate plus ammonia) were 2.2 and 1.9% of applied fertilizer, respectively. Due to dilution of the drainage water in the river, maximum daily herbicide (with the exception of 2,4‐D) and nutrient loadings to the river would not have resulted in significant concentration increases in the river water. There was no consistent remedial effect on herbicides entering the river due to passage of the drainage water through a natural wetland. In contrast, a considerable portion of the nutrients entering the river originated from the wetland.
Management Practice Effects on Phosphorus Losses in Runoff in Corn Production Systems
Authors: Bundy L. G. , Andraski T. W. , Powell J. M. 
Published: June 2010

ABSTRACTPhosphorus losses in runoff from cropland can contribute to nonpoint‐source pollution of surface waters. Management practices in corn (Zea mays L.) production systems may influence P losses. Field experiments with treatments including differing soil test P levels, tillage and manure application combinations, and manure and biosolids application histories were used to assess these management practice effects on P losses. Runoff from simulated rainfall (76 mm h−1) was collected from 0.83‐m2 areas for 1 h after rainfall initiation and analyzed for dissolved reactive P (DRP), bioavailable P, total P (TP), and sediment. In no‐till corn, both DRP concentration and load increased as Bray P1 soil test (STP) increased from 8 to 62 mg kg−1 A 5‐yr history of manure or biosolids application greatly increased STP and DRP concentrations in runoff. The 5‐yr manure treatment had higher DRP concentration but lower DRP load than the 5‐yr biosolids treatment, probably due to residue accumulation and lower runoff in the manure treatment. Studies of tillage and manure application effects on P losses showed that tillage to incorporate manure generally lowered runoff DRP concentration but increased TP concentration and loads due to increased sediment loss. Management practices have a major influence on P losses in runoff in corn production systems that may overshadow the effects of STP alone. Results from this work, showing that some practices may have opposite effects on DRP vs. TP losses, emphasize the need to design management recommendations to minimize losses of those P forms with the greatest pollution potential.
Differentiating Nonpoint Sources of Deisopropylatrazine in Surface Water Using Discrimination Diagrams
Authors: Meyer M. T. , Thurman E. M. , Goolsby D. A. 
Published: June 2010

ABSTRACTPesticide degradates account for a significant portion of the pesticide load in surface water. Because pesticides with similar structures may degrade to the same degradate, it is important to distinguish between different sources of parent compounds that have different regulatory and environmental implications. A discrimination diagram, which is a sample plot of chemical data that differentiates between different parent compounds, was used for the first time to distinguish whether sources other than atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) contributed the chlorinated degradate, deisopropylatrazine (DIA; 6‐chloro‐N‐ethyl‐1,3,5‐triazine‐2,4‐diamine) to the Iroquois and Delaware Rivers. The concentration ratio of deisopropylatrazine to deethylatrazine [6‐chloro‐N‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], called the D2R, was used to discriminate atrazine as a source of DIA from other parent sources, such as cyanazine (2‐[[4‐chloro‐6‐(ethylamino)‐1,3,5‐triazin‐2‐yl]amino]‐2‐methylpropionitrile) and simazine (6‐chloro‐N,N′‐diethyl‐1,3,5‐triazine‐2,4‐diamine). The ratio of atrazine to cyanazine (ACR) used in conjunction with the D2R showed that after atrazine, cyanazine was the main contributor of DIA in surface water. The D2R also showed that cyanazine, and to a much lesser extent simazine, contributed a considerable amount (∼40%) of the DIA that was transported during the flood of the Mississippi River in 1993. The D2R may continue to be a useful discriminator in determining changes in the nonpoint sources of DIA in surface water as cyanazine is currently being removed from the market.
In Situ Push–Pull Method to Determine Ground Water Denitrification in Riparian Zones
Authors: Addy Kelly , Kellogg D. Q. , Gold Arthur J. , Groffman Peter M. , Ferendo Gina , Sawyer Carl 
Published: June 2010

ABSTRACTTo quantify ground water denitrification in discrete locations of riparian aquifers, we modified and evaluated an in situ method based on conservative tracers and15N‐enriched nitrate. Ground water was “pushed” (i.e., injected) into a mini‐piezometer and then “pulled” (i.e., extracted) from the same mini‐piezometer after an incubation period. This push–pull method was applied in replicate mini‐piezometers at two Rhode Island riparian sites, one fresh water and one brackish water. Conservative tracer pretests were conducted to determine incubation periods, ranging from 5 to 120 h, to optimize recovery of introduced plumes. For nitrate push–pull tests, we used two conservative tracers, sulfur hexafluoride and bromide, to provide insight into plume recovery. The two conservative tracers behaved similarly. The dosing solutions were amended with15N‐enriched nitrate that enabled us to quantify the mass of denitrification gases generated during the incubation period. The in situ push–pull method detected substantial denitrification rates at a site where we had previously observed high denitrification rates. At our brackish site, we found high rates of ground water denitrification in marsh locations and minimal denitrification in soils fringing the marsh. The push–pull method can provide useful insights into spatial and temporal patterns of denitrification in riparian zones. The method is robust and results are not seriously affected by dilution or degassing from ground water to soil air. In conjunction with measurements of ground water flowpaths, this method holds promise for evaluating the influence of site and management factors on the ground water nitrate removal capacity of riparian zones.
A Dynamic Two‐Dimensional System for Measuring Volatile Organic Compound Volatilization and Movement in Soils
Authors: Allaire S.E. , Yates S.R. , Ernst F.F. , Gan J. 
Published: June 2010

ABSTRACTThere is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two‐dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real‐time concentration measurement. Gas distribution in the soil profile was sampled with gas‐tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed–furrow system. A 5‐h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3‐bromo‐1‐propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br−) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration–time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models.
Adsorption of Arsenate and Arsenite on Ferrihydrite in the Presence and Absence of Dissolved Organic Carbon
Authors: Grafe Markus , Eick Matthew J. , Grossl Paul R. , Saunders Amy M. 
Published: June 2010

ABSTRACTThe adsorption of As(V) and As(III) on synthetic two‐line ferrihydrite in the presence and absence of a peat humic acid (HAp), Suwannee River fulvic acid (FA), or citric acid (CA) was investigated. Previous work with goethite has demonstrated the ability of dissolved organic carbon (DOC) to decrease As(V) and As(III) adsorption. The results obtained demonstrate that As(V) adsorption on ferrihydrite was decreased only in the presence of CA. Arsenate decreased the adsorption of all organic acids except HAp Both FA and CA reduced As(III) adsorption on ferrihydrite, while HAp had no effect. Fulvic and citric acid adsorption on ferrihydrite was decreased in the presence of As(III); however, FA and CA adsorption increased at lower pH, which was consistent with decreased As(III) adsorption. Peat humic acid did not decrease As(III) adsorption, and we believe that the adsorption process of HAp and As(III) and As(V) on ferrihydrite are independent of each other. Previously, we observed that As(V) adsorption on goethite decreased in the presence of HAp > FA > CA, while As(III) adsorption on goethite was decreased similarly to that on ferrihydrite in the presence of CA > FA ≈ HAp, yet As(III) adsorption on ferrihydrite was greater than on goethite. The observed differences between this study and the earlier study on goethite are believed to be an intricate function of ferrihydrite's surface characteristics, which affect the mechanisms of adsorption and hence the affinity of organic acids such as HAp, FA, and CA for the ferrihydrite surface. As such, the adsorption of DOCs to ferrihydrite are assumed to be less favorable and to occur with a fewer number of ligands, resulting in lower surface coverage of weaker bond strength.