bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Tebuthiuron on Characteristic Green Algae Found in Playa Lakes
Authors: Price David J. , Murphy Brian R. , Smith Loren M. 
Published: July 2010

AbstractThere are many studies on the effects of tebuthiuron (N‐(5‐(1,1‐dimethylethyl)‐1,3,4‐thiadiazol‐2‐yl)‐N,N′‐dimethylurea) on organisms, but only limited information regarding the impact that the herbicide has on green algae. Eleven species of green algae common to playa lakes were exposed tebuthiuron in 400‐mL microcosm cultures. The cultures were treated with 0.18 µg/mL tebuthiuron, simulating the highest concentration of the herbicide found in natural runoff from agricultural areas treated with > 2.24 kg/ha tebuthiuron. Sixty‐six cultures were treated before active growth (first treatment) and 45 separate cultures were treated after maximum growth (second treatment). The first treatment was used to simulate the exposure of algal communities to tebuthiuron from runoff during the wet months of May and June. The second treatment simulated exposure to the herbicide once the community was established. Production and nutrient uptake by treated algal cultures was decreased by the first treatment with tebuthiuron. Of the eleven algal species selected, only Bracteacoccus minor was significantly inhibited by tebuthiuron in the first treatment. Photosynthetic pigments, total cell counts, and packed cell volumes for cultures exposed to tebuthiuron in the first treatment were lower than controls (P < 0.05). Effects caused by the herbicide on the cultures were also evidenced by decreased water quality variables in cultures treated before active growth, with the exceptions of orthophosphates and chloride. No differences were detected between controls and treated samples 210 d after initial treatment with tebuthiuron. Once the algae reached stable cell numbers (second treatment), tebuthiuron demonstrated no significant (P < 0.05) effects on the cultures. This study indicated that runoff from agricultural fields treated with concentrations > 2.24 kg/ha tebuthiuron may adversely affect the green algal communities of playa lakes.
Trichloroethylene Residuals in the Capillary Fringe as Affected by Air‐Entry Pressures
Authors: Cary J. W. , McBride J. F. , Simmons C. S. 
Published: July 2010

AbstractTrichloroethylene (TCE) was allowed to drain through columns of soil with the capillary water fringe controlled at various depths. Outflow was measured as well as the TCE content when TCE drainage stopped. Two soils, a sand and a loamy sand, with air‐entry values of 23 and 3 cm of water, respectively, were used. The sand with the large air‐entry value retained more TCE below the capillary water fringe following TCE drainage than the loamy sand with a smaller air‐entry pressure. The TCE below the saturated water fringe in both soils varied from almost 7% on a volume basis to <2%. The majority of the TCE in both soils was shown to resist further drainage when water was passed through the soils, suggesting the TCE phase was mostly fragmented. After 10 pore volumes of water was passed, the residual TCE content was 5.5 and 2.1% for the sand and loamy sand, respectively. Even though TCE has a greater specific gravity than water, it was shown in agreement with capillary theory, that TCE will not necessarily sink through the saturated water fringe to the bottom of an aquifer. Its tendency to do so is inversely proportional to the air‐entry pressure of the porous mineral phase. The results bring out several practical points for managing contaminated areas.
Trace Metals in Soil, Vegetation, and Voles from Mine Land Treated with Sewage Sludge
Authors: Alberici T. M. , Sopper W. E. , Storm G. L. , Yahner R. H. 
Published: July 2010

AbstractTrace‐metal concentrations in soil, vegetation, and tissues of meadow voles (Microtus pennsylvanicus) were compared on a strip‐mined site reclaimed conventionally (control site) and with municipal sludge (treated site) in Somerset County, Pennsylvania, in March and April 1983. With the exception of Zn concentrations in birdsfoot trefoil (Lotus corniculatus L.), reclamation with municipal sludge did not increase trace metal concentrations in soil, vegetation, or meadow voles in comparison to the site reclaimed conventionally. Zinc concentration in birdsfoot trefoil from the site reclaimed with sludge was higher than that from the site reclaimed conventionally but was below phytotoxic levels. Concentrations of Cu, Zn, Co, Cd, and Ni in vole tissues were not significantly different between control and treated sites. However, Cr concentrations in kidney and bone and Pb concentrations in liver and bone were higher on the control site than on the treated site. Stomach analyses indicated that meadow voles preferred tall fescue (Festuca arundinaceae L.) and quackgrass (Agropyron repens L.) to birdsfoot trefoil and orchardgrass (Dactylis glomerata L.).
Application of Sewage Sludge and Other Amendments to Coal Refuse Material: III. Effects on Percolate Water Composition
Authors: Pietz R. I. , Carlson C. R. , Peterson J. R. , Zenz D. R. , Lue‐Hing C. 
Published: July 2010

AbstractThe effects of sewage sludge, lime, and gypsum on the chemical composition of percolate from acidic coal refuse material was studied at a Fulton County, IL, land reclamation site. Treatments consisted of a control, 542 dry Mg ha−1 anaerobically digested sewage sludge, 89.6 Mg ha−1 lime, 112 Mg ha−1 gypsum, and combinations of these amendments. The chemical composition of the percolate collected monthly (1976 to 1980) from suction lysimeters at a 1‐m depth reflected the treatments applied to the coal refuse material. Percolate pH, NH+4‐N and [NO−3 + NO−2]‐N levels were lowest in either the gypsum or control treatments and highest in the sewage sludge treatment. Percolate SO4 levels were lowest in either the control or sludge‐amended treatments and highest in the gypsum‐amended treatments. Levels of NH+4‐N and [NO−3 + NO−2]‐N in percolating waters from the sludge‐amended treatments declined with time, while P levels remained at <2.3 mg L−1. Percolate concentrations of Al, Cr, Cu, Fe, and Zn were lowest in the sewage sludge treatment and highest in gypsum‐amended treatments. Metal solubility in the percolate was affected by the chemical composition of the coal refuse material and the applied amendments. Percolate Al, Cd, Cr, Cu, Fe, Ni, and Zn levels were negatively related (P ≤ 0.01) to pH in the sludge and sludge + lime treatments. Estimated concentrations of the various metals at a specific pH indicates that the sludge and sludge + lime treatments were very effective in reducing metal leaching when the percolate pH was ≥5.0. The application rates of lime and sewage sludge based on theoretical procedures were effective for about 5 yr. For long‐term (>5 yr) reclamation, the effectiveness of the sludge and sludge + lime treatments would be better maintained by applying more sludge (1050 Mg ha−1) and (900 to 1350 Mg ha−1) + lime (134 to 189 Mg ha−1) initially. The factor of two difference between the theoretical and actual amounts of lime and sewage sludge needed in the field suggests that an added safety factor of one and a half to two for application of these amendments is desirable for long‐term reclamation of coal refuse material.
Copper Toxicity in Tomato Plants
Authors: Rhoads F. M. , Olson S. M. , Manning A. 
Published: July 2010

AbstractCopper (Cu)‐containing fungicides and bactericides are used extensively for disease control on staked tomatoes (Lycopersicon esculentum Mill.) in North Florida. Since Cu moves very little in most soils, the potential for Cu buildup in tomato fields is substantial over a period of continuous tomato culture. The purpose of this research was to determine the Cu levels of soil and plant tissue, which are associated with reduced growth, and the influence of soil acidity on Cu uptake and growth response of tomatoes to soil Cu. Tomato plants were grown for approximately 6 wk in a greenhouse in pots of soil (Typic Paleudult) containing two levels of calcitic lime and six levels of copper hydroxide in a factorial treatment arrangement. Lime levels were 0 and 3.5 g kg−1 in Experiment 1 and 0 and 7.0 g kg−1 in Experiment 2. Copper levels were 0, 175, 350, 700, 1400, and 2800 mg kg−1 in Experiment 1 and 0, 44, 88, 175, 350, and 700 mg kg−1 in Experiment 2. Tissue‐Cu concentration was not a conclusive indicator of Cu toxicity in tomatoes. Soil pH and Mehlich 1‐extractable Cu provided sufficient information for determining if soil‐Cu levels were reducing plant growth. Near‐maximum Cu concentration in tomato tissue occurred at soil‐Cu levels above 104 mg kg−1. Plant growth was reduced with soil‐Cu levels above 150 mg kg−1 and soil pH below 6.5. However, soil‐Cu levels above 330 mg kg−1 were necessary to reduce plant growth with soil pH above 6.5.
Exchange of Nitrogen, Phosphorus, and Organic Carbon between Transplanted Marshes and Estuarine Waters
Authors: Craft C. B. , Broome S. W. , Seneca E. D. 
Published: July 2010

AbstractFluxes of N, P, and organic C were measured between irregularly flooded transplanted marshes and estuarine waters at two sites in North Carolina. Hydrologic flux was regulated by pumping estuarine water into the marsh, holding the water for 24 h and pumping the water out. Samples were collected from waters flowing into and out of each marsh and analyzed for salinity, N, P, and organic C. Concentrations of dissolved organic C were significantly higher in water flowing out of the two transplanted marshes compared to concentrations in inflow waters. In contrast, inflow waters contained significantly higher concentrations of phosphate than outflow waters. Phosphate flux was seasonal with maximum uptake by the marsh during the summer. Estimates of nutrient fluxes indicate that transplanted marshes export dissolved organic C (3–48 mmol m−2 event) and N (0.2–5.6) and import ammonium (300–600 µmol m−2 event) and phosphate (300–1000). The transplanted marshes are young communities that lack the large soil organic matter reservoirs and reducing environment characteristic of many natural marshes. These systems probably will continue to import ammonium and phosphate until the soils become reduced and soil nutrient reservoirs develop.
Pressurized Layer Reduces Transport through Compacted Clay Liners
Authors: Kluitenberg G. J. , Horton R. 
Published: July 2010

AbstractCompacted clay liners are often used in hazardous waste surface impoundments and landfills to provide a physical barrier to the flow of leachate. If a liner develops cracks or regions of high conductivity, convective fluxes can lead to increased chemical transport through the liner. In this study, we investigate the use of a pressurized layer of coarse material sandwiched between two compacted clayey soil layers to eliminate the hydraulic gradient across the upper layer. Our hypothesis is that such a system would limit convective transport through cracks or regions of high conductivity. Miscible displacement experiments were conducted using compaction permeameters filled with layered and unlayered soil materials. Experiments were carried out with and without a “worst case” hole penetrating the soil columns vertically. The experimental results show that, by using the pressurized interlayer in the presence of a worst case hole, both mean solute travel times and times to first breakthrough were significantly greater than when no interlayer was used. Travel times and time to first breakthrough were also increased when the pressurized interlayer was introduced in a column not containing a hole. The experimental results also serve to demonstrate the devastating effect of a small crack or hole on solute transport.
Sample Size Requirements for Estimation of Throughfall Chemistry Beneath a Mixed Hardwood Forest
Authors: Kostelnik K. M. , Lynch J. A. , Grimm J. W. , Corbett E. S. 
Published: July 2010

AbstractSix rainfall events were intensively sampled below a mixed hardwood forest canopy in central Pennsylvania to determine sample size requirements for estimation of thronghfall volumes and ionic concentrations. Evaluation of the ionic parameters of thronghfall revealed that the concentrations of most major ions were nonnormally distributed. Differences in the distributions of concentrations were found to occur between ions as well as between storms. Significant departures from normality were mainly due to right‐skewness. Only H+ exhibited a left skewed sample distribution. None of the basic transformations were effective in normalizing all parameters. A high degree of spatial variability was observed for each of the chemical parameters. Nitrate and hydrogen ions (NO−3 and H+), were found to be the least variable, whereas vegetatively mobile ions such as K+ and Mg2+ exhibited the greatest variability. Because of high event‐to‐event variation in the distributions of ion concentrations, specific sample‐size requirements should be estimated for each ion through preliminary sampling of thronghfall precipitation from several storms.
Aboveground Dissolution of Tebuthiuron Particles Placed Beneath the Crowns of Small Pinyon Trees
Authors: Van Pelt Nicholas S. , West Neil E. 
Published: July 2010

AbstractPlacement of large tebuthiuron {N‐[5‐(1,1 dimethylethyl)‐1,3,4‐thiadiazol‐2yl]‐N,N′‐dimethylurea} particles (briquettes) beneath tree canopies inhibits rainfall‐driven mobilization of the active ingredient. Briquette displacement and dissolution patterns were studied at two central Utah sites after 8‐month (cool seasons) and 4‐month (summer) exposure periods. Thirty‐two 1.8 g (13% a.i.) Graslan Brush Bullets per tree were placed at the dripline, midcrown, and stem base of 24 similar pinyon pine (Pinus edulis Engelm. and P. monophylla Torr. & Frem) saplings. The effects of site, placement, and direction from the stem were analyzed via a balanced, nested factorial experiment. Residues were entirely relocatable, indicating that overland flow, wind, and animals did not move briquettes. The influence of individual trees, placement, and direction strongly depended on season. Summer thunderstorms were three times more effective per unit of precipitation than winter rain and snow. Subcanopy placements permitted 65% as much dissolution as the exposed interspace, with stemflow more effective than throughfall in summer. Directional effects caused by storm paths were mild, and only evident at the dripline after summer exposure. Stem‐base applications or smaller particles should minimize site, season, and tree effects and ensure rapid, uniform control of woody‐weed regrowth with minimal undesired impacts.
Water Treatment Sludge Influence on the Growth of Sorghum‐Sudangrass
Authors: Heil D. M. , Barbarick K. A. 
Published: July 2010

AbstractDisposal of water treatment sludges (freshwater coagulant sludges), which are primarily amorphous Fe and Al compounds, poses a management problem for most municipalities in Colorado and other states. Previous studies indicate that water treatment sludges have a high capacity to fix P and that plant P deficiencies develop when plants are grown in sludge‐soil mixtures. No attempt has been made to quantify the ability of water treatment sludges to fix P to determine specific application rate recommendations. This research was initiated to determine acceptable application rates of three types of water treatment sludges added to the Colby (Ustic Torriorthent; pH = 7.5) and Red Feather (Lithic Cryoboralf; pH = 5.5) soils. A greenhouse study was conducted utilizing mixtures of an alum, iron, or organic polymer sludge combined with each of the two soils at rates of 0, 5, 10, 15, 20, and 25 g kg−1. Three cuttings of sorghum‐sudangrass [Sorghum bicolor L. Moench ‘NB280S’‐S. sudanense (Piper) Stapf] were taken. The Langmuir adsorption isotherm approach gave an accurate prediction of the relative fixation capacity of different sludges and consequently the effect of different sludge rates on P uptake by plants. Total plant yield and plant uptake data indicated that positive plant growth responses to sludge above those in the control (0 g kg−1) were the result of improved Fe availability in the Colby soil, and possibly increased soil pH in the Red Feather soil. Yields declined at higher sludge application rates (15 – 25 g kg−1) as compared to low application rates (5 – 10 g kg−1) probably due to increased P fixation by sludge. Plant concentrations of Al, Cu, Mn, Ni, and Pb were not high enough to decrease plant growth; however, Cd concentrations associated with 20 and 25 g alum sludge kg−1 Red Feather soil were greater than 2 mg kg−1. This is the upper limit reported for normal concentrations in plants and it may pose a threat to livestock that consume this forage.
Characterization of Phosphorus in Sludge Extracts Using Phosphorus‐31 Nuclear Magnetic Resonance Spectroscopy
Authors: Hinedi Zeina R. , Chang A. C. , Lee R. W. K. 
Published: July 2010

AbstractNuclear magnetic resonance spectroscopy (31P NMR) was used to characterize the phosphorus (P) extracted from selected municipal sewage sludges. Aqueous and nonaqueous extraction schemes were studied. The trichloroacetic acid/KOH two‐step extraction and the 0.5 M NaOH extraction were effective in recovering P from sludges. It was found that the P distribution pattern is sludges was affected by the sludge digestion processes. Almost all of the P in anaerobically digested sludges was inorganic. In the waste‐activated sludge and aerobically digested sludges, more than 50% of the total P was present as P‐monoesters and P‐diesters. Several experiments were conducted to confirm P‐diester peak assignment. Incubation of the sludge with ribonuclease caused a decrease of the peak in the P‐diester region, indicating that at least a part of the P‐diesters is in the form of RNA. Results of a dialysis experiment appeared to indicate that P‐diesters were broken down from the molecular weight >1000 material to their lower molecular weight components during sludge digestion. The peaks appearing in the 31P NMR spectra of sludge‐borne phospholipids were tentatively assigned to phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and phosphatidylglycerol or diphosphatidylglycerol.
Adsorption of Sulfate by Kaolinite and Amorphous Iron Oxide in the Presence of Organic Ligands
Authors: Inskeep William P. 
Published: July 2010

AbstractThe ability of soils to adsorb SO4 is an important factor in determining the effect of acidic deposition on the transport of H+ and cations in terrestrial ecosystems. However, the role of soluble organic acids and humic substances on the adsorption of SO4 is poorly understood. Consequently, this study was conducted to determine the effects of soluble organic ligands on the adsorption of SO4 by amorphous iron oxide (AIO) and kaolinite (KGa‐2). Adsorption experiments were conducted by titrating 50 mM K2SO4 with suspensions of KGa‐2 (146‐583 m2L−1) or AIO (324 m2L−1) in 0.01 M KCl, at pH 4.3 and 25 °C. Sulfate adsorption was studied over a range in total SO4 of 0.01 to 2.5 mM in the absence and presence of organic ligands including Seward humic and fulvic acid, tannic acid, citric acid, oxalic acid, and gallic acid. Sulfate adsorption capacities in the absence of organic ligands were 3.5 and 1.3 µmolc m−2 at 324 m2L−1 AIO and 583 m2L−1 KGa‐2, respectively. Humic and tannic acid present at 1.4 to 3.6 mM total soluble C reduced SO4 adsorption by KGa‐2 at total SO4 levels below 0.12 mM. Humic, tannic, citric, gallic, and oxalic acid were all effective at inhibiting SO4 adsorption by AIO. In several cases the percent of SO4 adsorbed was reduced from near 100 to zero at total SO4 levels below 0.12 mM. The amount of inhibition was related to the quantity of oxygen‐containing functional groups added rather than the total soluble C. These results indicate that organic acids compete for SO4 adsorption sites and that the presence of organic acids in soil solutions will influence SO4 adsorption capacities.
Heavy Metal Concentrations During Ten Years of Sludge Treatment to an Old‐Field Community
Authors: Levine M. Beth , Hall A. Tilghman , Barrett Gary W. , Taylor Douglas H. 
Published: July 2010

AbstractHeavy metal concentrations were determined in three trophic levels of an old‐field community treated for 10 consecutive years with sewage sludge. The study site consisted of sludge‐treated, fertilizer‐treated, and control plots. Cadmium concentrations were highest each year in soils, vegetation, meadow vole (Microtus pennsylvanicus Ord.) livers, and earthworms (Lumbricus rubellus Hoffmeister, L. terrestris L.) from sludge‐treated plots. Mean Cd concentrations in sludge decreased from 59.0 mg kg−1 in 1978 to 19.8 mg kg−1 in 1987, whereas Cd concentrations in soil increased from 1.13 mg kg−1 in 1979 to 1.94 mg kg−1 in 1987. Plant species in sludge plots had significantly higher Cd concentration values than those collected from fertilizer or control plots. No yearly increase in Cd content was observed in meadow vole liver or kidney. Cadmium concentrations in earthworms were significantly greater in 1981 (139.2 mg kg−1) than in 1987 (60.9 mg kg−1). Copper concentrations were highest in soils, giant foxtail (Setaria faberii Hermm.), and earthworms from sludge‐treated plots. Mean Cu concentrations in sludge ranged from 320.0 mg kg−1 in 1978 to 380.6 mg kg−1 in 1984. Copper concentrations in soil ranged from 14.7 mg kg−1 in 1979 to 36.9 mg kg−1 in 1986. Vegetation in sludge plots concentrated Cu less than vegetation in fertilizer or control plots. Cu concentrations in meadow vole liver decreased from 5.0 to 3.1 mg kg−1 and in kidneys from 4.9 to 3.3 mg kg−1 in 1978 and 1987, respectively. Copper concentration in earthworms ranged from 17.1 mg kg−1 in 1981 to 23.0 mg kg−1 in 1987. Although Pb concentrations in sludge declined from 473.0 mg kg−1 in 1978 to 243.0 mg kg−1 in 1987, mean Pb concentrations in soil increased from 19.0 mg kg−1 in 1979 to 48.4 mg kg−1 in 1986. However, only giant foxtail in sludge‐treated plots significantly concentrated Pb. Mean Pb concentrations in earthworms ranged from 8.06 mg kg−1 in 1986 to 16.8 mg kg−1 in 1987. Mean Zn concentrations in sludge ranged from 865.8 mg kg−1 in 1987 to 1281.0 mg kg−1 in 1984. Zinc concentrations in soils increased from 52.4 mg kg−1 in 1979 to 107.2 mg kg−1 in 1987. Zinc concentrations varied substantially among plant species; mean Zn concentrations in 1987 ranged from 41.0 mg kg−1 for Rubus frondosus Bigel. (a perennial) to 97.3 mg kg−1 for giant foxtail (a summer annual). Zinc concentrations in earthworms decreased from 1218.5 mg kg−1 in 1981 to 615.5 mg kg−1 for 1987. The detritivore trophic level bioconcentrated heavy metals more than producer or primary consumer levels.
Tebuthiuron Persistence and Distribution in Some Semiarid Soils
Authors: Johnsen Thomas N. , Morton Howard L. 
Published: July 2010

AbstractTebuthiuron (N[5‐(1,1‐dimethylethyl)‐1,3,4‐thiadiazol‐2‐yl]‐N,N'‐dimethylurea) is a soil‐applied herbicide used on rangelands to control weeds and brush. This study was conducted at five previously treated semiarid rangeland locations in northcentral Arizona to determine how long tebuthiuron remains in the soil and to what depths it penetrates into the soil. Treatments were made from 1975 through 1979. Soils were collected from 1980 through 1986 at 0‐ to 7‐cm, 7‐to 15‐cm, and successive 15‐cm layers to bedrock or into caliche layers from the perimeter of 3‐ by 0.5‐m trenches dug perpendicular to the long axis of the plots. Tebuthiuron was assayed using gas chromatography with flame photometric detection. Tebuthiuron was detected in soil 11 yr after application. Most of the tebuthiuron detected was in the surface 30 cm of soil during the first 5 yr, but small amounts were detected as deep as 105 cm 6 and 9 yr after treatment. After 9 yr from 55 to 73% of the tebuthiuron detected was at the depth of between 60 and 90 cm.