bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pesticide‐Contaminated Soil Sample Stability during Frozen Storage
Authors: Puchalski Michele , Horvath Gareth , Loughran Michael , Elsner Gary , Koskinen William 
Published: July 2010

AbstractLittle information is available in the literature on pesticide‐contaminated soil sample stability during frozen storage. This research was conducted to evaluate the effects of sample holding times on frozen clay loam, clay, and loamy sand soils spiked with eight different herbicides: EPTC (S‐ethyl dipropylthiocarbamate); trifluralin (α, α, α‐trifluoro‐2,6‐dinitor‐N,N‐dipropyl‐p‐toluidine); atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1.3.5‐triazine‐2,4‐diamine); alachlor (2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide); dicamba (3,6‐dichloro‐2‐methoxybenzoic acid); 2,4‐D (2,4‐dichlorophenoxyacetic acid); silvex ((±)‐2‐(2,4,5‐trichlorophenoxy)propionic acid); and 2,4,5‐TB (4‐(2,4,5‐trichlorophenoxy)butanoic acid). Each soil was spiked with eight herbicides (1 mg kg−1 each herbicide) and stored at −15°C for up to 450 d. The pesticides tested could generally be stored up to 450 d without affecting pesticide recovery on all soil types with the exception of trifluralin. Trifluralin decreased by 50% in the loamy sand, 40% in the clay loam, and 66% in the clay soil over the length of the study. In the loamy sand, clay loam, and clay soils a significant decrease in trifluralin concentration occurred at Day 180, 360, and 270, respectively. This study shows that long‐term frozen storage can affect the sample integrity of some pesticide‐contaminated soils. In addition, soil type can be a factor in sample integrity during frozen storage. Spiked controls should be a part of quality assurance and quality control during long‐term frozen storage.
Mercury and Organic Carbon Relationships in Streams Draining Forested Upland/Peatland Watersheds
Authors: Kolka R. K. , Grigal D. F. , Verry E. S. , Nater E. A. 
Published: July 2010

AbstractWe determined the fluxes of total mercury (HgT), total organic carbon (TOC), and dissolved organic carbon (DOC) from five upland/peatland watersheds at the watershed outlet. The difference between TOC and DOC was defined as particulate OC (POC). Concentrations of HgT showed moderate to strong relationships with POC (R2 = 0.77) when all watersheds were grouped. Although POC only accounts for 10 to 20% of the OC transported, we estimate that it is associated with 52 to 80% of the HgT transported from the five watersheds. Total transport of HgT from the watersheds ranged from 0.70 to 2.82 µg m−2 yr−1. Watershed geometry and hydrology play important roles in determining the influence of OC on HgT transport in forested watersheds. Watershed properties such as peatland area have considerable promise as predictors for estimating HgT transport in streams draining forested watersheds in the Great Lakes States.
Copper Solution Geochemistry in Arable Soils: Field Observations and Model Application
Authors: Römkens Paul , Hoenderboom Guido , Dolfing Jan 
Published: July 2010

AbstractThe solubility and vertical displacement of Cu in near neutral arable soils largely depends on the presence of dissolved organic carbon (DOC) in solution. In this paper the solubility of Cu in sandy soils is predicted by a previously calibrated model that describes Cu binding to both low and high molecular weight components of DOC. Soil solution samples were obtained by centrifugation of field moist soil. Dissolved Cu concentrations increased with DOC and total soil Cu content, but decreased with organic matter and pH; after lime application, both DOC and Cu solubility were strongly reduced in the CuSO4‐treated soils. No single multiple linear regression equation could be obtained, however, that was able to describe the dissolved Cu concentrations in the various treatments. In contrast to this, a two‐species Langmuir model enabled us to describe the dissolved Cu concentrations in soil solution samples quite well in the pH range from 4.2 to 6 in both contaminated and noncontaminated soils (R2 = 0.5–0.9 for various treatments). Measured Cu concentrations were generally underpredicted by the model below pH 4.2. In the manured soil, the predictive capacity of the model decreased with depth (R2 = 0.6 in the topsoil to 0.3 in the deeper soil horizons), which is most likely related to changes in the nature of DOC. The use of a relatively simple model that requires only a few input parameters may prove useful for the prediction of the solubility of Cu under field conditions.
Ammonia Volatilization from Freshwater Fish Ponds
Authors: Gross A. , Boyd C. E. , Wood C. W. 
Published: July 2010

AbstractThis study evaluated ammonia (NH3) emissions to the atmosphere from fishpond waters and uneaten, floating feed. Channel catfish (Ictalurus punctatus) were stocked at 550 pond−1 in four, 400‐m2 ponds at the Auburn University Fisheries Research (AUFRU), Auburn, AL, on 30 May 1997. Feed (28% crude protein), prepared as floating pellets was applied daily. Ponds were harvested between 7 and 9 Oct. 1997. Ammonia traps were placed in ponds on a weather vane sampler. Ammonia emissions were measured from June through September 1997. In addition, NH3 volatilization from wetted catfish feed was measured in a laboratory experiment. Average NH3 volatilization from ponds ranged between 8.8 to 71.0 mg NH3‐N m2 d−1, and averaged 3.75% of total NH3 nitrogen (TAN) concentration in water. Positive linear correlations were found between the amount of feed applied and TAN concentration in the water and between TAN and NH3 volatilization. Volatilization from wetted feed was not a major NH3 loss to the atmosphere. The study suggested that 24 kg ha−1 of N were lost to the atmosphere between 23 June 1997 and 30 Sept. 1997 from ponds into which 158 kg ha−1 N were applied. In the USA, there are about 66 000 ha of catfish ponds. Extrapolation from this study suggests that 1584 t of NH3 could volatilize from catfish ponds each summer.
Effectiveness of Switchgrass Filter Strips in Removing Dissolved Atrazine and Metolachlor from Runoff
Authors: Mersie W. , Seybold C. A. , McNamee C. , Huang J. 
Published: July 2010

AbstractThe effectiveness of switchgrass (Panicum virgatum L.) filter strips in removing dissolved atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine) and metolachlor (2‐chloro‐N‐2‐ethyl‐6‐methylphenyl‐N‐2‐methoxy‐1‐methylethyl acetamide) in runoff was investigated using aluminum‐tilted beds set at 1% slope, filled with Emporia sandy loam soil (fine‐loamy, siliceous, thermic Typic Hapludults) and planted to switchgrass. Solution containing herbicides, followed by water alone after 2 and 4 wk were applied on the up slope of beds with and without switchgrass. Water samples from surface flow, lateral, and vertical leachates as well as soil samples were analyzed for the two herbicides using a gas chromatograph. Switchgrass filter strips reduced the mass of dissolved atrazine and metolachlor by 52 and 59% from the applied runon, respectively. The bare soil strips removed 41% of atrazine and 44% of metolachlor. Less than 0.5% of the applied herbicide was released by the two water runons 2 and 4 wk after herbicide‐solution application. The average concentrations of both herbicides in surface runoff were greater than in leachate samples. Herbicides were removed by the soil as runon moved through the soil profile. The concentration of either herbicide on the top surface (0–2.5 cm) was greater than in the soil immediately below (2.5–5 cm). Degradation of both herbicides was faster in beds with switchgrass than without. Greater amounts of both herbicides were retained in the first 67‐cm section of beds with the grass than without. Switchgrass helped to remove the herbicides by slowing runoff velocity and increasing their retention by soil.
Relating Agricultural Land Uses to In‐Stream Stormwater Quality
Authors: McFarland Anne M. S. , Hauck Larry M. 
Published: July 2010

AbstractSixteen largely agricultural watersheds in the upper portion of the North Bosque River of central Texas were instrumented to collect storm event samples for nutrient analysis. Flow‐weighted storm‐event mean concentrations were averaged across storm events to characterize the water quality at each site for storms sampled between November 1992 and August 1995. Nutrient concentrations were related to land uses above sampling sites using correlation and regression analysis to indicate major sources of nutrient nonpoint source pollution to the upper North Bosque River. Consistently, N and P concentrations increased as the proportion of land area used for dairy waste application fields (or milking cow densities) increased in the drainage basins above sampling sites. The proportion of total P (TP) in runoff represented by soluble reactive P (SRP) also increased as the percent of dairy waste application fields above a sampling site increased; likely as a response to the common practice of surface application of manure to permanent pasture. This increase in SRP is of particular importance because SRP is readily bioavailable in aquatic systems, thus increasing the potential for accelerated eutrophication in receiving waterbodies. The results of these analyses indicate a strong association between in‐stream nutrient concentrations during storm events and the percent of dairy waste application fields comprising a drainage area. This indicates a need to manage the movement of nutrients, particularly soluble P, from manure application fields in areas where in‐stream nutrient levels are considered a nonpoint source pollution problem.
Modeling Nitrogen Oxide Emissions from Current and Alternative Pastures in Costa Rica
Authors: Plant Roel A. J. , Bouman Bas A. M. 
Published: July 2010

AbstractEmissions of nitrogen (N) oxide were simulated for one current, unsustainable pasture management system (Natural) and two alternative, sustainable systems (Grass‐Legume and Fertilized Improved) relevant to the Northern Atlantic Zone (NAZ) of Costa Rica. To produce frequency distributions of N oxide emissions, an expert system for generating technical coefficients of pastures was linked with a process‐based simulation model. The expert model generated parameter sets representing different options for the three management systems. The simulation model was rerun for each parameter set. Simulated nitrous oxide (N2O)‐N losses 25 yr after pasture establishment were 3 to 5 kg ha−1 yr−1 for natural pastures, 12 to 15 for grass‐legume mixtures, and 7 to 28 for fertilized grasses. Losses of nitric oxide (NO)‐N were 1 to 2 kg ha−1 yr−1 for natural pastures, 7 to 8 for grass‐legume mixtures, and 3 to 16 for fertilized grasses. Stepwise multiple regression showed that N2O‐N losses were explained by annual C input to the soil (R2 = 0.997), and NO‐N losses by attainable dry matter production (R2 = 0.972). Carbon input and dry matter production were controlled by stocking rate and fertilizer level. Soilatmosphere N oxide emissions from pastures may increase by a factor 3 to 5 when natural pastures are converted to improved pastures. Such conversion may increase the sustainability of the pasture by stopping the decline of soil N. However, the change is not necessarily sustainable from a global perspective because it increases the emission of N oxide greenhouse gases.
Volatilization of Methyl Isothiocyanate from Soil after Application of Metam‐Sodium with Two Techniques
Authors: van den Berg F. , Smelt J. H. , Boesten J. J. T. I , Teunissen W. 
Published: July 2010

AbstractThe large‐scale use of soil fumigants results in substantial emissions into the air. To describe the fate of these chemicals in soil, the PEST‐icide Leaching and Accumulation (PESTLA) model was extended to include the diffusion of pesticides through the gas phase and their volatilization at the soil surface. The model was tested against measurements of methyl isothiocyanate after injection of metam‐sodium into the soil at 0.19‐m depth with a blade injector and after injection at 0.10‐m depth followed by rototillage. For both techniques, the fumigant behavior in soil was described reasonably well. The volatilization rates measured in the field corresponded roughly to the rates computed. After injection with the blade injector at 0.19‐m depth, the initial volatilization rates measured were higher than those computed. This is possibly the result of rapid diffusion of fumigant through large voids in the topsoil. Such heterogeneities were not accounted for in the model. For shallow injection followed by rototillage, the volatilization rates were high from the start, both in the computations and measurements. The cumulative volatilization of methyl isothiocyanate when injecting metam‐sodium at 0.19‐m depth was computed to range up to a few percent of the dosage. When shallow injection was followed by rototillage, the computed cumulative emission ranged between 17 and 34% of the dosage. The model can be used to evaluate the effect of different factors on the volatilization of fumigants and that of other, soil‐incorporated pesticides from homogeneous noncracking soils, but for the evaluation of tillage factors model development is needed.
Sorption of Chlorobiphenyls in Sediment—Water Systems Containing Nonionic Surfactants
Authors: Park Jae‐Woo , Boyd Stephen A. 
Published: July 2010

AbstractNonionic surfactants may aid remediation of contaminated soils and sediments by increasing aqueous concentrations of poorly water‐soluble organic contaminants. In order to explore the effects of nonionic surfactants on the sediment—water distribution of PCBs, a series of batch experiments was performed using four commercial nonionic surfactants (Triton X‐100, Triton X‐405, Triton X‐705, and Tween 80) and Red Cedar River sediment. Sediment—water distributions of 4,4′‐dichlorobiphenyl (Di‐CB), 2,2′,4,4′‐tetrachlorobiphenyl (Tetra‐CB), and 2,2′,4,4′,5,5′‐hexachlorobiphenyl (Hexa‐CB) were studied at aqueous surfactant concentrations ranging from zero to >1.5 times the critical micelle concentration (CMC) of each surfactant. The results show decreases in apparent soil—water distribution coefficients (K*) of PCB congeners at all surfactant concentrations as compared to the intrinsic sorption coefficient (K) in the absence of surfactant, unlike that previously reported. A new model incorporating a surface micellization concept for the sorbed surfactant phase was successfully applied to experimental data presented here and in a previous study.
Ground Water Nitrate Removal in Subsoil of Forested and Mowed Riparian Buffer Zones
Authors: Addy K. L. , Gold A. J. , Groffman P. M. , Jacinthe P. A. 
Published: July 2010

AbstractWe studied two similar riparian sites in southern New England and examined ground water nitrate (NO−3‐N) removal in the subsurface of mowed (i.e., herbaceous) vs. forested (i.e., woody) vegetation. Each site consisted of poorly drained, fine to medium sands and contained adjacent areas of mowed and forested vegetation. We dosed mesocosms with bromide and 15N labeled NO−3‐N amended ground water to simulate the shallow ground water NO−3‐N dynamics of riparian buffer zones. Mesocosms were composed of undisturbed, horizontal soil cores (40 cm long, 15 cm diam.) extracted from seasonally saturated subsoil We observed substantial ground water NO−3‐N removal and denitrification at all locations. Ground water NO−3‐N removal rates were significantly correlated with carbon‐enriched patches of organic matter. This correlation supports previous work that patches function as hotspots of microbial activity in the subsoil. Within each site, we found no significant difference in ground water NO−3‐N removal rates in the subsoil of forested and mowed areas and we noted tree roots throughout the subsoil of the mowed areas. We found that ground water NO3‐N removal rates differed significantly between similar sites. We caution against ascribing specific ground water NO−3‐N removal rates to different riparian aboveground vegetation types without recognizing the importance of site differences, e.g., water table dynamics, land use legacy and adjacent vegetation. Riparian zones composed of a mix of forested and mowed vegetation, common in agroforestry and suburban land uses, may remove substantial amounts of ground water NO−3‐N.
Predicting Nitrate Leaching from Drained Arable Soils Derived from Glacial Till
Authors: Vinten A. J. A. 
Published: July 2010

AbstractRegional‐scale prediction of ground and surface water pollution by nitrate (NO3) requires field‐scale prediction of NO3 leaching. This can be done by a N balance sheet approach, but this is not robust, because no account is taken of organic matter dynamics or denitrification. In this paper, predictions of NO3 leaching made using a balance sheet method and those using a dynamic N cycle model, Agricultural Nitrogen Model (ANIMO), are compared with observations of NO3 leaching from drained plot experiments on two Scottish arable soils, a clay loam (aquic Haplaquept) and a sandy loam (dystric Eutrochrept). Mineral N fertilizer applications in these experiments varied from 0 to 210 kg N ha−1 and the mean observed NO3‐N leaching to drains was 21 kg N ha−1 for the clay loam and 53 kg N ha−1 for the sandy loam. The balance sheet method on average overpredicted NO3 leaching by 120% for the clay loam and underpredicted by 16% for the sandy loam. ANIMO predictions using default parameters were poor but when subsoil respiration was included to a depth of 0.7 m at the clay loam site and 2.0 m at the sandy loam site, the mean predicted NO3‐N leaching was within 2% of observed. The root mean square error was still quite large (76 and 53% for the clay loam and sandy loam, respectively) and the correlation coefficient was poor at the clay loam site (r = 0.09 and 0.91 for the clay loam and sandy loam, respectively). Simulated denitrification losses are strongly dependent on the depth to which soil respiration occurs. Work is needed to obtain more direct evidence of subsoil denitrification. Heterogeneity of topsoil organic matter and respiration may also need to be taken into account.
Using Granulated Wood Charcoal as a Filter Medium
Authors: Agbanobi R. O. 
Published: July 2010

AbstractThe use of activated carbon (AC) filtration and chlorination to polish wastewater effluent is becoming increasingly costly. A cost‐effective approach is needed to clean large volumes of wastewater often discharged into surface waters or used to recharge depleted ground water aquifers. Hardwood charcoal is characterized by large pore size, which makes it a possible media for absorbing bacteria and organic matter, similar to AC in filtration capabilities. To determine the efficiency of granular wood charcoal (GWC) as a filter medium, a comparative study was carried out in a laboratory test using GWC and sand. The results showed that GWC is superior to the sand in pollutant removal and length of effectiveness. This is important because GWC can be obtained at relatively little cost. This is an effective and environmentally sound approach for recycling the growing volume of wood charcoal in the municipal solid waste stream.
Enzyme and Earthworm Activities during Vermicomposting of Carbaryl‐Treated Sewage Sludge
Authors: Benitez E. , Nogales R. , Elvira C. , Masciandaro G. , Ceccanti B. 
Published: July 2010

AbstractThe feasibility of vermicomposting pesticide contaminated refuses was evaluated. A mixture of sewage sludges was amended, at a ratio of 1:1 (v/v), with a garden refuse artificially contaminated with carbaryl, a carbamate insecticide commonly used in farming and gardening. Ten clitellated earthworms were then placed in this material. We determined the evolution of earthworm (Eisenia foetida, Savigny) biomass and changes in enzyme activities during an 18‐wk period of sewage sludge vermicomposting. The carbaryl produced a chronically toxic effect on the earthworms, measured by weight gain and sexual maturity. The growth was slower in the presence of pesticide. In addition, carbaryl treatments showed inhibited enzyme activity in the first weeks of the vermicomposting process, slowing down organic matter biodegradation. The dynamics of the vermicomposting process can be followed by combining easily detectable parameters related to the global microbial metabolism: a traditional chemical (water‐soluble C/water‐soluble N) and biochemical (dehydrogenase activity/water‐soluble C) index, were calculated. In particular, this last seemed more useful in characterizing the vermicomposting process even a longer maturation time (10–18 wk).
Single‐Phase Microemulsification of a Complex Light‐Nonaqueous‐Phase‐Liquid: Laboratory Evaluation of Several Mixtures of Surfactant/Alcohol Solutions
Authors: Rhue R. Dean , Rao P. Suresh C. , Annable Michael D. 
Published: July 2010

AbstractA recent advance in conventional pump‐and‐treat technology for aquifer remediation involves the use of surfactant‐alcohol mixtures that will form a clear, transparent, thermodynamically stable oil‐in‐water microemulsion on contact with a residual non‐aqueousphase‐liquid (NAPL). An initial screening of 86 commercial‐grade surfactants for aqueous solubility resulted in selection of 58 that were further tested in batch experiments to evaluate the capacity to solubilize a complex NAPL waste collected from a Superfund site (Operable Unit OU‐1) at Hill AFB, UT. The selected group of 58 surfactants represented six classes of anionic, nine classes of nonionic, and one class of amphoteric surfactants. Batch studies on NAPL solubilization identified a number of surfactants suitable for use in the field demonstration phase of the project; a further criterion in surfactant selection was that the flushing solution had a viscosity <2 cp. The best surfactants among this group had HLB (hydrophilic‐lipophilic balance) values between 12 and 13, and solubilized 10 to 20 g L−1 of the OU‐1 NAPL when the surfactant concentration was 3%. Column tests using NAPL‐coated glass beads showed that the more efficient surfactants could remove >90% of the NAPL after flushing with <10 pore volumes. Brij 97, an ethoxylated alcohol ether surfactant, showed a high capacity for solubilizing the OU‐1 NAPL. In a column test using contaminated Hill AFB aquifer material, flushing with a mixture of 3% Brij 97 and 2.5% n‐pentanol removed essentially all of the mass of nine target analytes in the NAPL after flushing with <10 pore volumes without mobilizing the NAPL or destabilizing aquifer colloids.
Volatile Organic Compound Losses from Sewage Sludge‐Amended Soils
Authors: Wilson S. C. , Jones K. C. 
Published: July 2010

AbstractVolatile organic compounds (VOCs) applied to soil in sludge have been assumed to disappear quickly and completely. The VOC behavior in sludge‐amended soils has been studied previously only in laboratory systems where the sludged soil has been spiked with compounds of interest. Behavior in these systems may not necessarily represent compound behavior in field soils to which contaminated sludge is added. A series of laboratory microcosm experiments were designed therefore to investigate the behavior of toluene, ethyl benzene, o‐, m‐, and p‐xylene applied to soil in contaminated sludge, and factors influencing loss processes. The VOC loss from sludge‐amended soil was well described by a simple one step pseudo‐first‐order model but in certain soils was better described by a two step first‐order model. Volatilization was the predominant loss process. Rates of loss depended on sludge application rate, method of sludge application, soil properties, and on compound characteristics. Experiments indicated that spiking sludge‐amended soils gave a reasonable indication of VOC loss rates from systems amended with contaminated sludge at least over a period of 23 d. The majority of VOCs applied to soils in sludge volatilizes quickly to the atmosphere over a few to 10s of days with a small fraction lost more slowly. Potential for VOC crop uptake, livestock ingestion, and contamination of ground water (the transfer routes of most concern) is low under routine, managed applications of sewage sludge to agricultural land.