bluuebunny/crossref_metadata_2025 huggingface dataset:
Arsenic Speciation: Involvement in Evaluation of Environmental Impact Caused by Mine Wastes
Authors: Roussel Christophe , Bril Hubert , Fernandez Angel
Published: July 2010

Since large areas have been contaminated by arsenic‐rich industrial and mining by‐products in several countries, knowledge of arsenic (As) behavior in soils and water is of major concern for reclamation of polluted sites and evaluation of environmental risk. Cheni's tailings (France) contains average concentrations up to 7000 mg kg−1 As and was listed by the authority as an important potentially pollutant site. Because As speciation determines its mobility, it was investigated in surface and ground waters of the site and a study of the solid As‐bearing phase was performed on suspended particulate material (SPM). Results of sequential extraction, carried out on the SPM collected in drainage waters, show that most of total extracted As (78%) and Fe (77%) is bound to an iron hydrous oxide phase, which was determined to be lepidocrocite (γ‐FeOOH) by x‐ray diffraction and infrared spectrometry. Particulate material was >220 times more concentrated than dissolved As. Conditions for the stability of dissolved (<0.45 µm) arsenite [As(III)] and arsenate [As(V)] are discussed on the basis of thermodynamical data and field measurements of pH and redox potentials. The theoretical stability of As(V) corresponds to a large association between As and particulate material, and large amounts of the metalloid are released in solution when As‐rich particles come from oxidized ground waters to moderately reduced conditions. These results are important for evaluating, modeling, and rehabilitating As‐polluted sites.
Processing Environmental Samples Containing Organic Chemicals Using Polymeric Microfilters
Authors: Xing Baoshan
Published: July 2010

This paper describes a study to determine the sorption of five herbicides and three organic contaminants by five polymeric microfilters. The five filters had different membrane and housing makeups: (i) nylon‐polypropylene (NY‐PP), (ii) borosilicate glass‐acrylic (BA‐AC) (iii) polyethersulfone‐acrylic (PS‐AC), (iv) polyvinylidene difluoride‐polypropylene (PV‐PP), and (v) PTFE‐polypropylene (PT‐PP). The herbicides were isoxaflutole, diketonitrile, atrazine, metolachlor, and 2,4‐D; the contaminants were trichloroethylene, α‐naphthol, and phenanthrene. All five filters strongly sorbed the eight chemicals (except for three filters for 2,4‐D) and sorption was largest at the first passage and declined with the increasing number of passages. The first passage sorption of isoxaflutole followed a decreasing order: PV‐PP (92%) > BA‐AC (87%) > PS‐AC (42%) > PT‐PP (38%) > NY‐PP (26%); diketonitrile: BA‐AC (69%) > PV‐PP (22%) > PS‐AC (18%) = NY‐PP (18%) > PT‐PP (12%); metolachlor: BA‐AC (76%) ≥ PV‐PP (75%) > PT‐PP (32%) > PS‐AC (23%) = NY‐PP (23%); atrazine: BA‐AC (78%) > NY‐PP (24%) > PS‐AC (19%) ≥ PT‐PP (17%) ≥ PV‐PP (15%); 2,4‐D: NY‐PP (22%) > PV‐PP (7.8%) > BA‐AC (1.4%) ≥ PS‐AC (0.99%) ≥ PT‐PP (0.41%); trichloroethylene: BA‐AC (86%) > PS‐AC (35%) > PV‐PP (18%) ≥ NY‐PP (16%) ≥ PT‐PP (15%); α‐naphthol: BA‐AC (99%) = NY‐PP (99%) > PV‐PP (49%) = PS‐AC (49%) > PT‐PP (6.8%); and phenanthrene: PV‐PP (99%) = PS‐AC (99%) = NY‐PP (99%) = BA‐AC (99%) > PT‐PP (42%). These filters are not suitable for preparing and processing environmental samples involving these eight chemicals (except for three filters for 2,4‐D) unless some corrected measures are taken.
Inorganic Nitrogen in Drainage Water from Grazed Grassland in Northern Ireland
Authors: Watson C. J. , Jordan C. , Lennox S. D. , Smith R. V. , Steen R. W. J.
Published: July 2010

The loss of inorganic N in drainage water from grazed perennial ryegrass (Lolium perenne L. cv. Talbot) swards in Northern Ireland was studied for 9 yr. Plots (each 0.2‐ha area) were hydrologically isolated and artificially drained to V‐notch weirs with flow‐proportional monitoring of drainage water. Nitrogen, as calcium ammonium nitrate, was applied at 100, 200, 300, 400, or 500 kg N ha−1 yr−1. The efficiency of flow interception by drains decreased on average by 39% during the 9 yr. Annual loss of NO−3 in drain flow for the plot receiving 300 kg N ha−1 yr−1 ranged from 16 to 52 kg N ha−1 and was highest after a dry summer. In individual years, NO−3 in drainage water was linearly related to fertilizer N input with 5 to 23% of the added N input being lost. The shape of the NO−3 dose‐response curve did not change with time. Annual losses of NH+4 and NO−2 in drainage water were not related to fertilizer rate, and ranged from 0.2 to 4 kg N ha−1 and 8 to 540 g N ha−1, respectively. Annual flow‐weighted mean NO−3, NH+4, and NO−2 concentrations usually did not exceed the European Community maximum admissible limits for drinking water below a fertilizer N application rate of 300 kg N ha−1 yr−1. However, the European Community guideline NH+4 and NO−2 concentrations in salmonid and cyprinid waters were exceeded at application rates ≥100 kg N ha−1 yr−1.
Combined Effects of Ozone and Nitrogen on Secondary Compounds, Amino Acids, and Aphid Performance in Scots Pine
Authors: Kainulainen P. , Holopainen J. K. , Holopainen T.
Published: July 2010

Combined effects of O3 and N supply on Scots pine (Pinus sylvestris L.) were studied in two separate growth chamber experiments exposing seedlings to 0, 0.075, 0.15, and 0.3 µL/L of O3 during 8 h/d, 5 d/wk for a period of 5 wk. Seedlings were fertilized with low, medium, and high levels of N. Ozone and N availability affected concentrations of several primary and secondary metabolites. More changes on metabolites were detected in Exp. 1 (with seedlings ceasing their annual growth) than in Exp. 2 (with seedlings actively growing). Overall, high O3 exposure levels significantly decreased concentrations of monoterpenes and increased concentrations of resin acids. Concentrations of total phenolics were not affected by O3 exposure. Mostly lower concentrations of monoterpenes and resin acids were found at a medium N‐fertilization level than at low and high N‐fertilization levels, while total phenolic concentration decreased by enhanced N availability. In Exp. 1, significantly elevated concentrations of free amino acids were found at O3 concentration of 0.3 µL/L. Nitrogen availability did not have remarkable effects on amino acid concentrations. In Exp. 1, both O3 and N had a significant effect on the MRGR of the aphid Schizolachnus pineti. In Exp. 2, the weight of the females and nymphs and the total number of reproduced nymphs were significantly affected by O3 and N. Only a few interaction effects were found, suggesting that the N supply does not significantly modify O3‐induced effects on studied primary and secondary compounds and aphid performance in Scots pine seedlings.
Pulp Sludge as a Component in Manufactured Topsoil
Authors: Carpenter Andrew F. , Fernandez Ivan J.
Published: July 2010

The primary objective of this study was to evaluate the use of uncomposted, de‐watered pulp sludge as the organic matter component in a manufactured topsoil. Seven manufactured topsoils, containing 5.1, 8.8, 9.6, 10.9, or 13.8% pulp sludge and 0, 8.4, or 20.7% flume grit on a dry weight basis, were applied to an abandoned gravel pit. Manufactured topsoils and a control topsoil were evaluated for (i) impacts on soil and soil solution chemistry and (ii) effectiveness as a growing medium for a grass conservation mix and hybrid poplars (Populus spp.). Significant N mineralization was evident in all of the manufactured topsoils within the first field season. Soil cation exchange capacity (CEC), pH and P availability were positively correlated to pulp sludge loading rate. In soil solution, the highest concentrations of solutes were detected within 2 mo of topsoil placement and were dominated by NO3‐N and Ca. Cumulative grass yields from the 15 mo following topsoil placement were greater than those in the control topsoil and ranged from 3.9 to 7.3 Mg ha−1 in the manufactured topsoils. Tree height, diameter growth, and foliar nutrient concentrations responded positively to the manufactured topsoils. Results from this study indicate that topsoils manufactured with pulp sludge as the organic matter component can be an environmentally sound alternative to natural topsoil for the reclamation of sites on which existing conditions necessitate importing topsoil for revegetation.
Vegetation Dieback on Clay‐Capped Pyritic Mine Waste
Authors: Menzies N. W. , Mulligan D. R.
Published: July 2010

Waste rock dumps at the abandoned Rum Jungle uranium mine were capped with clay covers in order to limit entrance of water and oxygen into the dump, and hence to reduce generation of acid drainage. The soil covers consisted of a clay seal layer overlain by moisture retention and erosion resistant layers and stabilized with vegetation. An investigation of this cover system, primarily at one of the dumps, was undertaken in response to the concern that the vegetation dieback apparent on some areas was spreading. Reduced vegetative cover could potentially threaten the integrity and effectiveness of the rehabilitation. Areas of vegetation dieback on soil covers were shown to be the result of Cu toxicity. The soil covers had been acidified and contaminated with Cu by capillary rise of water from pyritic waste immediately underlying the soil capping. Over time, the surface soil on areas with progressively deeper capping is being contaminated, resulting in a gradual expansion of the bare area. The activity of Al3+ in the soil solution appears to be controlled in these contaminated soils by the solubility of an Al‐SO4 mineral, resulting in nonphytotoxic Al levels in the surface soil, despite the low pH. The lower portion of the clay seal layer was sufficiently acid that Al toxicity would restrict root growth.
Evaluation of Fluoride‐Induced Metal Mobilization in Soil Columns
Authors: Totsche Kai Uwe , Wilcke Wolfgang , Körber Markus , Kobza Jozef , Zech Wolfgang
Published: July 2010

Fluoride in soil solution may cause substantially increased leaching of dissolved organic carbon (DOC), Al, and heavy metals from soils. Our objective was to examine whether increased metal solubility is attributable to formation of fluoro‐ or organo‐complexes. The A horizon of a Slovak soil contaminated with heavy metals and F by Al smelter emissions was used to conduct two column experiments under saturated and steady‐state water flow conditions. The columns were leached with 5 mM Na2SO4, 1 mM NaCl, and 9 mM NaF solutions at pH 5.5 and an electrical conductivity of 1000 µS cm−1. Samples were collected in 70‐min intervals for approximately 7 d. Two experiments were performed. In the first experiment (single F pulse), a fluoride (F) pulse was applied for 36 pore volumes (PVs), while in the second experiment (dual F pulse), two consecutive F pulses (each for 2.8 PVs) were applied. For both experiments, Cl breakthrough curves (BTCs) revealed a convection‐dominated transport regime. The breakthrough of Cd, Cr, Fe, Ni, and Pb paralleled DOC breakthrough in both experiments indicating metal leaching as organo‐complex. In the dual F pulse experiment, peak separation of the DOC and the complexed F (Fbound) breakthrough was achieved. The highest Fbound concentration occurred 3.8 PVs later than that of DOC. The Al BTC paralleled that of Fbbound but showed tailing with a turning point simultaneous to the highest DOC concentration. Thus, the increase in Al solubility was mainly caused by fluoro‐complexation and only to a lesser extent by organo‐complexation.
Anion Transport in Columns of Variable Charge Subsoils: Nitrate and Chloride
Authors: Qafoku Nikolla P. , Sumner Malcolm E. , Radcliffe David E.
Published: July 2010

Acid variable charge subsoils exhibit a positive charge, which retards the passage of anions through the soil profile. The objective was to study the NO−3 adsorption isotherms and the effect of changing the subsoil positive charge on NO−3 and Cl− retention, estimate NO−3 and Cl− retardation in different subsoils, and quantify relationships between transport and adsorption parameters. Subsoils from different subtropical and tropical areas were used in column experiments. Four lime treatments and four leaching solutions were used to create different anion exchange capacities (AECs) in subsoils. In the Cecil subsoil (Fine, kaolinitic, thermic Typic Kanhapludult), NO−3 isotherms were linear between 5 and 30 mmol NO−3 L−1. When forced through the origin, an L‐curve NO−3 isotherm was observed at native and low soil pH. The NO−3 adsorption was largely affected by the changes in both pH and concentration of the leaching solution. Other variable charge subsoils have varying capacities to retard anions, which is reduced when either soil pH or leaching solution concentration is increased. Both parameters equally reduce the distribution coefficient Kd and the retardation coefficient R. The AEC correlates closely with R and Kd. As a result, AEC can be successfully used in the solute transport models to estimate Kd or R without measuring it to correct for the NO−3 retardation.
Runoff Water Quality from Poultry Litter‐Treated Pasture and Forest Sites
Authors: Sauer T. J. , Daniel T. C. , Nichols D. J. , West C. P. , Moore P. A. , Wheeler G. L.
Published: July 2010

In the Ozark Highlands of the USA (36–38° N, 91–95° W), annual application of poultry litter to pasture land is a routine waste management practice. The objective of this study was to measure the effect of site characteristics and poultry litter application on runoff and nutrient transport from grazed pasture and forest sites at different landscape positions. Sixteen pairs of 1 × 2 m plots were established on Nixa (loamy‐skeletal, siliceous, active, mesic Glossic Fragiudults) and Clarksville (loamy‐skeletal, siliceous, semiactive, mesic Typic Paleudults) cherty silt loams. One plot of each pair received 4.5 Mg ha−1 of poultry litter. Rainfall was simulated at 75 mm h−1 for 1 h (25‐yr return period storm) one month after litter application. A composite runoff sample was analyzed for dissolved reactive phosphorus (DRP), total phosphorus (TP), ammonia N (NH3‐N), nitrate N (NO3‐N), total Kjeldahl nitrogen (TKN), and total suspended solids (TSS). Poultry litter‐treated plots had consistently higher concentrations of all water quality parameters tested compared to untreated plots. Concentration of DRP in runoff from untreated plots was linearly correlated with three soil P tests (0.35 < r2 < 0.85). Soil P on litter‐treated plots had little effect on runoff DRP, which averaged 2.20 mg L−1. High variation in runoff resulted in only NO3‐N showing significantly greater losses due to poultry litter treatment at two pasture sites. Results indicate that variation in runoff has a significant effect on nutrient transport from grazed pastures receiving poultry litter.
Runoff, Solids, and Contaminant Losses into Surface Tile Inlets Draining Lacustrine Depressions
Authors: Ginting D. , Moncrief J. F. , Gupta S. C.
Published: July 2010

Surface tile inlets connected to subsurface tile lines provide a direct pathway for pollutants to enter water bodies. This study was conducted to evaluate the quantity and quality of surface runoff entering surface tile inlets draining natural depressions of lacustrine landscapes. Surface runoff, solids, and nutrient losses via surface tile‐inlets in two lacustrine watersheds in the southern Minnesota River Basin were investigated from 1995 to 1998. Tillage and crop rotations were: (i) fall NH3‐N injection after soybean [Glycine max (L.) Merr.] or navy bean (Phaseolus vulgaris vat. vulgaris) harvest and (ii) fall chisel plowing after corn (Zea mays subsp, mays) harvest, followed by spring field cultivation, planting, harrowing, and row cultivation. Maximum annual runoff loss via surface inlets was less than 5% of annual precipitation. Flow‐weighted total P (TP) concentration ranged from 0.2 to 2.9 mg L−1 in snowmelt and 0.7 to 6.5 mg L−1 in rainfall runoff. Nitrate N concentrations were less than 10 mg L−1. Three‐year maximum cumulative pollutant loads were: 138 kg ha−1 total solids (TS), 20 kg ha−1 chemical oxygen demand (COD), 363 g ha−1 TP, 205 g ha−1 dissolved molybdate reactive P (DMRP), 1342 g ha−1 total dissolved inorganic N (TDIN), and 1126 g ha−1 nitrate N. Most of the dissolved pollutants were associated with snowmelt runoff and most of the particulate pollutants were associated with major storms. Losses of particulate pollutants via surface tile inlets are smaller than expected doe to the dynamics of ponding in natural landscape depressions.
Nitrous Oxide Flux from Solid Dairy Manure in Storage as Affected by Water Content and Redox Potential
Authors: Brown H. A. , Wagner‐Riddle C. , Thurtell G. W.
Published: July 2010

The current global N2O budget estimates that animal production contributes one third of agricultural emissions. A study was conducted on solid dairy manure to determine the potential for N2O emission during storage. A laboratory flow‐through chamber and tunable diode laser analyzer were employed to continuously quantify the N2O flux in a temperature‐controlled environment. Water, NO3‐N and NH4‐N contents and redox potential (Eh, using a platinum and Ag‐AgCl reference electrode) also were monitored. In Experiment 1, manure samples were collected (4.3 kg wet weight) from three layers near the surface of the pile (0–15, 15–30, and 30–45 cm) and incubated at 22°C for 20 d. The mean daily N2O‐N fluxes were between 0 and 0.33 g N m−2 d−1, and N2O was only generated in samples from the top two layers of the pile. In Experiment 2, samples from the 30‐ to 45‐cm depth were adjusted by amendment with chopped straw to 70, 75, and 80% water content (WC). These samples showed less variable fluxes and produced twice as much N2O‐N as the unamended samples. Levels of straw‐amendment had no significant effect on N2O emissions. Combined results from both experiments revealed that fluxes were highest at 55 to 70% WC and 150 to 250 mV Eh. The N2O emission was limited by low NO3‐N levels in samples with high WC and low Eh. Increasing WC and decreasing Eh with depth and increasing levels of NO3 in the surface layer over time revealed that the exterior of solid manure piles is crucial to the flux of N2O.
Retention of Pesticides in Filter Membranes
Authors: Clausen Liselotte
Published: July 2010

The objective of this work was to determine the retention of pesticides in membrane filters used for the separation of suspended solids from solutions. Five types of filter materials were tested: cellulose acetate, nylon, polyethersulfone, polyvinylidene fluoride (PVDF), and polytetra‐fluorethylene (PTFE). Five aqueous solutions of pesticides with initial concentrations of 9.5 μg/L were studied: atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine), isoproturon (3‐(4‐isopropylphenyl)‐1,1‐dimethylurea), mecoprop ((RS)‐2‐(4‐chloro‐o‐tolyloxy)‐propionic acid), 2,4‐D ((2,4‐dichlorophenoxy)acetic acid), and bentazone (3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4‐(3H)‐one 2,2‐dioxide). Detectable losses of pesticides were measured on all the tested filter materials. Cellulose acetate filter, nylon filter, and polyethersulfone filter retained between 3 and 90% of all five tested pesticides. On PVDF filter and PTFE filter the retention was limited, as only two (isoproturon and mecoprop) out of five pesticides was retained with a maximum retention of 4.2% for isoproturon on the PVDF filter. In the present study no correlation between retention by filters and pesticide solubility in water was observed. The results also demonstrate that pesticides with relatively high solubility and low octanol‐water partition coefficient (Kow values) can be strongly retained by synthetic filter materials.
Persistence and Biological Activity in Soil of Insecticidal Proteins from Bacillus thuringiensis and of Bacterial DNA Bound on Clays and Humic Acids
Authors: Stotzky G.
Published: July 2010

Insecticidal proteins produced by various subspecies of Bacillus thuringiensis and bacterial transforming DNA bind rapidly and tightly on clays, both pure mined clay minerals and soil clays, and on humic acids extracted from soil. This binding reduces the susceptibility of these biomolecules, which retain their biological activity when bound, to microbial degradation. The persistence of bound insecticidal toxins may enhance the control of target pests, constitute a hazard to nontarget organisms, and result in the selection and enrichment of toxin‐resistant target insects. The persistence of bound DNA has relevance to horizontal gene transfer in soil. Because of the large differences in the chemical composition and structure between these proteins and DNA, as well as between clays and humic acids, these studies can serve as models for the potential fate and effects of other biomolecules that will be introduced to soil from “factories” of transgenic plants and animals genetically engineered to produce vaccines, hormones, antibodies, toxins, pharmaceuticals, and other bioactive compounds.
Biogenic Nitrogen in Soils as Revealed by Solid‐State Carbon‐13 and Nitrogen‐15 Nuclear Magnetic Resonance Spectroscopy
Authors: Knicker Heike
Published: July 2010

Solid‐state nuclear magnetic resonance (NMR) spectroscopy represents a valuable nondestructive alternative to common chemolytic and thermolytic analytical approaches for characterizing the formation of humified organic N from biogenic precursors in soils. In this review, recent studies using solid‐state 15N NMR spectroscopy for the examination of the fate of biogenic N in soils are summarized. From their results it can be assumed that most of the N occurs as peptide‐like structures. Heterocyclic aromatic‐N was not identified to a large extent in naturally humified material but was observed in spectra obtained from a humic acid of a soil incubated with 15N‐labeled trinitrotoluene. The dominance of amide‐N in humified organic N is supported by the application of dipolar dephasing (DD) solid‐state 13C NMR spectroscopy. This technique can be used to estimate the relative content of N‐substituted aliphatic carbons and thus, to calculate the relative contribution of peptides to the total C and N content of a sample. Applying this technique to degraded plant and algal material and to a humic fraction obtained from a natural soil indicates that peptides comprise more than 80% of the total organic N in the examined samples. The solid‐state 15N NMR spectrum of a clay fraction of the Chinese Loess Plateau (age: 10 000 yr) reveals that some peptide‐like material can survive prolonged pedogenesis. Several explanations for the protection of these commonly thought labile compounds are available and discussed.
Ground Water Recharge Through Optimized Intensive Dairy Farms
Authors: Aarts H. F. M. , Habekotté B. , van Keulen H.
Published: July 2010

To meet the increasing demand for water for human consumption, surface water is increasingly used, generally at high purification costs, as ground water availability is limited. Sandy areas can “produce” high‐quality ground water based on infiltration and leaching of the precipitation surplus. In the Netherlands, as in many other countries, these areas are used by dairy farms. Because of intensification in the recent past, ground water recharge has declined as a result of increased water consumption by crops and its quality is deteriorating as a result of nutrient leaching. Possibilities were examined to improve management at farm level in such a way that the desired upper ground water quality could be realized and extractable ground water quantity for human consumption increased without reducing milk production intensity (11 900 kg ha−1). A prototype farm system was established on an experimental farm. Nitrate concentration in the upper ground water decreased from 200 to 50 mg L−1 (associated with reduced N surpluses) and ground water recharge could be increased by 550 m3 per ha (through reduced crop water consumption). Additional experimental farming system costs were below the costs for purifying 550 m3 surface water. Therefore, it is concluded that integrating ground water management in dairy farming is technically and economically feasible and therefore attractive for farmers, water companies, and consumers.
Airborne Contamination of Forest Soils by Carbonaceous Particles from Industrial Coal Processing
Authors: Schmidt Michael W. I. , Knicker Heike , Hatcher Patrick G. , Kögel‐Knabner Ingrid
Published: July 2010

In the German Ruhr‐area industrial coal processing emitted large amounts of carbonaceous particles for a century until 1970. Our objectives were to detect the presence of airborne carbonaceous particles and assess their impact on the chemical structure of soil organic matter in two forest soils (Podzols) with potential sources of carbonaceous particles approximately 10 to 30 km away. Contamination was not visible macroscopicaily. Organic matter was characterized in bulk soils and in particle‐size separates by elemental analysis, magnetic susceptibility measurement, reflected light microscopy, and 13C solid‐state nuclear magnetic resonance (NMR) spectroscopy. Organic and mineral horizons contained carbonaceous particles including char, coke, and bituminous coal from coal combustion, coking, coal processing, and steel production. In the organic horizons of both soils we observed a material high in magnetic susceptibility (max. 109 × 10−8 m3 kg−1), whereas in the mineral horizons only the Podzol with an intense intermixing moder‐type humus had high magnetic susceptibly. This Aeh horizon was extremely rich in organic carbon (139.4 g organic C kg−1), concentrated in the 20 to 2000 µm size separates. In the second Podzol, like in many natural soils, C concentrations were largest in the <20 µm separates. Bloch decay 13C magic angle spinning (MAS) NMR spectroscopy revealed a highly aromatic structure of the carbonaceous particles. Airborne carbonaceous particles formed a macroscopically indistinguishable mixture with natural soil organic matter and could be present in many soils neighboring industrialized areas.
Kinetics of Trichloroethylene Cometabolism and Toluene Biodegradation: Model Application to Soil Batch Experiments
Authors: El‐Farhan Yassar H. , Scow Kate M. , Fan Shifang , Rolston Dennis E.
Published: July 2010

Trichloroethylene (TCE) biodegradation in soil under aerobic conditions requires the presence of another compound, such as toluene, to support growth of microbial populations and enzyme induction. The biodegradation kinetics of TCE and toluene were examined by conducting three groups of experiments in soil: toluene only, toluene combined with low TCE concentrations, and toluene with TCE concentrations similar to or higher than toluene. The biodegradation of TCE and toluene and their interrelationships were modeled using a combination of several biodegradation functions. In the model, the pollutants were described as existing in the solid, liquid, and gas phases of soil, with biodegradation occurring only in the liquid phase. The distribution of the chemicals between the solid and liquid phase was described by a linear sorption isotherm, whereas liquid‐vapor partitioning was described by Henry's law. Results from 12 experiments with toluene only could be described by a single set of kinetic parameters. The same set of parameters could describe toluene degradation in 10 experiments where low TCE concentrations were present. From these 10 experiments a set of parameters describing TCE cometabolism induced by toluene also was obtained. The complete set of parameters was used to describe the biodegradation of both compounds in 15 additional experiments, where significant TCE toxicity and inhibition effects were expected. Toluene parameters were similar to values reported for pure culture systems. Parameters describing the interaction of TCE with toluene and biomass were different from reported values for pure cultures, suggesting that the presence of soil may have affected the cometabolic ability of the indigenous soil microbial populations.
Erodibility of Fly Ash Used as a Topsoil Substitute in Mineland Reclamation
Authors: Gorman James M. , Sencindiver John C. , Horvath Donald J. , Singh Rabindar N. , Keefer Robert F.
Published: July 2010

Fly ash, a by‐product of coal‐fired power plants, has been used successfully in reclaiming abandoned mine lands by improving mine‐soil chemical and physical properties. However, the fine sand‐silt particle size of fly ash may make it more susceptible than natural soils to detachment and transport by erosive processes. Furthermore, the high content of silt‐size particles in fly ash may make it more susceptible to surface crust formation, resulting in reduced infiltration and increased surface runoff and erosion. In the summer of 1989, fly ash‐wood waste mixtures, used as a topsoil substitute, were surface applied on two separate mine sites in Preston County, WV, one with 10% slope and the other 20% slope. Erosion rates were measured directly using the Linear Erosion/Elevation Measuring Instrument (LEMI). Erosion measurements were taken during the first two growing seasons on both sites. Erosion values were up to five times greater on the fly ash‐treated minesoil than on the untreated minesoil. Mulching with wood chips reduced fly ash erosion to about one‐half the loss of the unmulched plots. Erosion was related to both the amount and type of ground cover. Increased vegetative ground cover resulted in reduced erosion. Mosses and fungi appeared to provide better erosion protection than grass‐legume cover.
Effect of Nitrate on Uptake of Pertechnetate by Tomato Plants
Authors: Krijger G. C. , Kollöffel C. , Wolterbeek H. T.
Published: July 2010

Nitrate has been shown to affect the acquisition of the nuclear waste product technetium (Tc) by plants. The mechanism responsible for this phenomenon is unknown. The uptake of [99mTc]TcO−4, [35S] SO2−4 and H2[32P]PO−4 was studied in tomato plants (Lycopersicon esculentum Mill., cv. Tiny Tim) with different growth rates due to culture at 0.5, 4.0, or 30 mM NO−3. In experiments lasting 24 h, net TcO−4 uptake decreased at higher NO−3 supplies. The inhibitory effect of NO−3 on TcO−4 uptake also was shown in TcO−4 influx experiments (Ki = 3.3 mM), although about 30% of the TcO−4 influx is suggested to be insensitive to NO−3. In contrast, H2PO−4 (30 mM) did not inhibit TcO−4 influx, whereas SO2−4 (30 mM) tended to increase TcO−4 influx, probably due to the ionic strength of the uptake solution. Significant effects of the NO−3 supply on Tc efflux were not found. Overall, this leads to the conclusion that TcO−4 and NO−3 share at least one transporter.
Imazaquin Sorption in Highly Weathered Tropical Soils
Authors: Regitano J. B. , Alleoni L. R. F. , Vidal‐Torrado P. , Casagrande J. C. , Tornisielo V. L.
Published: July 2010

Imazaqnin is a herbicide used intensively in Brazil to control a large number of weeds associated with soybean [Glycine max (L.) Merr.]. Most of the Brazilian soils are highly weathered (50–60% are Oxisols). The extent of sorption and desorption of imazaquin in these soils will dictate its mobility and environmental fate once microbial degradation is negligible. Sorption and desorption of imazaquin were studied in nine samples (seven surface and two subsurface) from highly weathered soils and in two other soils. Sorption of imazaquin was low in all soils, except in the soil with high organic carbon content (OC) content and low soil‐solution pH (Typic Humaquept, GH soil). The OC and the soil‐solution pH were the soil attributes that correlated better with the amount of sorbed imazaquin in the studied highly weathered soils [r = 0.91 (significant at the 0.01 probability level) and −0.62 (significant at the 0.05 probability level), respectively]. The Fe oxide content was an important soil attribute affecting sorption of imazaquin when OC was low. In general, a model based on hydrophobic interactions was capable of predicting sorption of imazaquin. However, this model and others based on multivariate regression were not capable of predicting sorption of imazaquin on highly weathered soils with pH‐dependent charges and low OC, such as the subsurface acric soils. Low sorption implies a high potential for mobility and, therefore, imazaquin may reach important sources of drinking water. This potential for mobility may be diminished in highly weathered soils due to their acidic nature and high Fe and Al oxide contents.
Phosphorus Solubility in Biosolids‐Amended Farm Soils in the Mid‐Atlantic Region of the USA
Authors: Maguire R. O. , Sims J. T. , Coale F. J.
Published: July 2010

There have been increased environmental concerns about agricultural P management, including land application of biosolids (municipal sewage sludge). This study investigated the influence of current N‐based land application practices for biosolids on soil P. We collected soil samples from 11 biosolids application sites and from adjacent setback areas that had never received biosolids. These samples were analyzed for oxalate‐extractable phosphorus (Pox), aluminum (Alox, and iron (Feox); degree of phosphorus saturation (DPS = (Pox/0.61[Alox + Feox]) × 100), Mehlich‐1 P; iron‐oxide strip extractable phosphorus (FeO‐P); and water‐soluble phosphorus (WSP). In many cases Mehlich‐1 P was excessive (>50 mg kg−1), but this occurred in both application sites and setback areas. Biosolids application sites had significantly greater Pox in the topsoils (0 to 20 cm) when averaged for all sites, with means of 589 and 296 mg kg−1 in the application sites and setback areas, respectively. However, biosolids applications also increased [Feox + Alox], which meant that the DPS was not always increased. There was a trend for higher Pox and FeO‐P in the biosolids‐amended soil profiles (60‐cm depth) and highest P concentrations were consistently found at the 0‐ to 5‐cm depth. The net effect of biosolids applications on Pox, relative to [Feox + Alox], was related to FeO‐P. Our data suggest that adding biosolids according to current N‐based guidelines will lead to an accumulation of P in soils, but the release of this P may be mitigated by the associated increases in soil [Feox + Alox].
Volatilization of Nitrogen from Dewatered Biosolids
Authors: Robinson M. B. , Polglase P. J.
Published: July 2010

Volatilization of N from biosolids applied to land lessens the risk of ground water contamination and reduces the amount available for plant uptake. This study determined rates of volatilization of NH+4−N from biosolids after surface‐application. Biosolids from three sewage treatment plants (Cronulla, Liverpool, and Quakers Hill) in Sydney, Australia, were applied under controlled conditions to exclude leaching and plant uptake, and volatilization was calculated using a mass balance approach. Application rates supplied 100 to 168 g m−2 of total N including 20 to 67 g m−2 of NH+4‐N. Most loss of N occurred within 1 wk of application; within 3 wk 71 to 81% of the NH+4−N applied had been lost. Subsequent changes in NH+4−N were small and there was little loss of organic N. The rapidity and magnitude of loss in both NH+4−N and total N suggests that N was primarily lost by volatilization, and that denitrification losses, involving slower biological processes, were minimal. Amounts of NH+4−N volatilized were proportional to amounts applied. Loss of applied NH+4−N did not increase with regular re‐wetting, although loss of total N was increased, suggesting mineralization of organic N followed by gaseous loss. Volatilization, an important pathway for loss of N applied in biosolids, needs to be considered when calculating rates of biosolids application to protect ground water while providing nutritional benefit.
Radiocesium Uptake by One‐Year‐Old Willows Planted as Short Rotation Coppice
Authors: Gommers A. , Thiry Y. , Vandenhove H. , Vandecasteele C. M. , Smolders E. , Merckx R.
Published: July 2010

High radioactivity concentrations in foodcrops grown in areas contaminated by the Chernobyl accident continue to justify the consideration of a change in land use. Production of biofuel may be one of the alternatives to food production. However, present knowledge about radionuclide cycling in such systems is limited. In the present study, radiocesium uptake and distribution were measured in a willow (Salix viminalis L. var. Orm) short rotation coppice (SRC) stand. This system allows production of energy from the harvested biomass. Experimental plots were established on two soil types of contrasting texture (loamy versus sandy), and contaminated with 8 × 106 Bq 134Cs m−2. Concentrations of 134Cs were measured in wood, litter, roots, and cuttings after 1 yr of growth. At the end of the growing season, only 0.0012% (loamy soil) and 0.0065% (sandy soil) of the initial radiocesium was transferred to the plant biomass (including belowground plant parts). Stem wood contained the lowest concentration of 134Cs among all plant parts analyzed. Wood radiocesium concentrations were 82 Bq kg−1 for the loamy soil and 192 Bq kg−1 for the sandy soil. These values are well below the exemption limit for fuel wood put forward in the Commonwealth of Independent States (CIS) (740 Bq kg−1). Even at this high soil contamination level, radiocesium concentrations in wood do not exceed appreciably the naturally occuring 40K content in the wood (135 Bq kg−1).
Degradation and Volatilization of the Fumigant Chloropicrin after Soil Treatment
Authors: Gan J. , Yates S. R. , Ernst F. F. , Jury W. A.
Published: July 2010

Chloropicrin (CP) is used in fumigation of soil‐borne pests. Because of its high volatility and toxicity, atmospheric emission of CP during soil application may become a source of air pollution. We investigated degradation of CP in three different soils as a function of soil temperature and moisture conditions, and evaluated its volatilization against methyl bromide (MeBr) from packed soil columns. Chloropicrin degraded much faster than MeBr in the same soil, mainly via microbial degradation. Degradation of CP accelerated as soil temperature increased, but was relatively independent of changes in soil moisture. When the soil surface was uncovered, overall volatilization loss of CP was similar to that of MeBr. Covering the soil surface with a polyethylene or high‐barrier film was much more effective in reducing volatilization of CP than MeBr. Therefore, surface covers may be used in sensitive areas to reduce human exposure to CP.
Groundwater Quality Beneath Irrigated Vegetable Fields in a North‐Central U.S. Sand Plain
Authors: Stites Will , Kraft G. J.
Published: July 2010

The dramatic expansion of irrigated agriculture since about 1970 in the north‐central USA has been accompanied by NO3 and pesticide pollution of groundwater. The expansion has been concentrated in areas with sandy soils and shallow water tables, such as the Wisconsin central sand plain. In some parts of this sand plain, most wells contain detectable pesticide residues and NO3‐N concentrations that exceed the 10 mg L−1 U.S. drinking water maximum contaminant level (MCL). To evaluate the effects on groundwater quality of this agricultural system, we monitored solutes 23 times during a 2‐yr period in the upper 3 m of the aquifer beneath and immediately upgradient of four irrigated vegetable fields. Groundwater beneath fields had significantly greater concentrations of most solutes and lower pH than upgradient groundwater. Especially pronounced were Ca, Cl, K, Mg, and NO3 differences, with concentrations 5 to 26 times greater under fields. Nitrate N concentrations averaged 21 mg L−1 under fields, compared with 1 mg L−1 upgradient. Pesticide residues were ubiquitous beneath fields, and generally persisted for many months after application. Pesticide concentrations often exceeded Wisconsin preventive‐action limits (PALs), but seldom exceeded federal MCLs. Even when agricultural management approximated best management practice (BMP) recommendations, the NO3 concentration beneath these fields approached double the MCL, indicating a need for new approaches to control agricultural groundwater pollution.
Modeling Nitrate Nitrogen Leaching in Response to Nitrogen Fertilizer Rate and Tile Drain Depth or Spacing for Southern Minnesota, USA
Authors: Davis D. M. , Gowda P. H. , Mulla D. J. , Randall G. W.
Published: July 2010

The Agricultural Drainage and Pesticide Transport (ADAPT) simulation model was used to evaluate the relative effects of nitrogen application rate, tile‐drain spacing, and tile‐drain depth on NO3‐N losses through tile drains for conditions that are typical of the Upper Midwestern USA. The ADAPT model, a daily time‐step continuous water table management model, was calibrated and validated for tile drainage and associated NO3‐N losses using long‐term monitoring data measured on three experimental plots of a Webster clay loam (fine‐loamy, mixed, superactive, mesic Typic Endoaquoll) under continuous corn (Zea mays L.) with conventional tillage treatment. For the calibration period, the model predicted mean monthly tile drainage and NO3‐N losses of 4.6 cm and 6.7 kg ha−1, respectively, against measured tile drainage and NO3‐N losses of 4.6 cm and 6.9 kg ha−1, respectively. For the validation period, the predicted mean monthly tile drainage and NO3‐N losses were 4.0 cm and 6.1 kg ha−1, respectively, against measured tile drainage and NO3‐N losses of 3.7 cm and 6.5 kg ha−1, respectively. Long‐term simulations were made for a wide range of climatic conditions between 1915 and 1996 to evaluate the effect of drain spacing, drain depth, and N application rates on tile drainage and NO3‐N losses. Simulation results indicate that much greater reductions in NO3‐N losses occur with reduced N application rates than with increases in drain spacing or decreases in drain depth.
Recovery of Giardia and Cryptosporidium from Water by Various Concentration, Elution, and Purification Techniques
Authors: Hsu Bing‐Mu , Huang Chihpin
Published: July 2010

The performances of different concentration and elution techniques, as well as two purification methods, were evaluated in terms of their recovery efficiencies of Giardia cysts and Cryptosporidium oocysts from seeded deionized water, treated water, and raw water samples. Out of the three concentration techniques, the Envirochek capsule filtration followed by the membrane filtration consistently gave the highest recovery efficiencies for both protozoan parasites. Although the cartridge filtration is the most suitable technique for handling large quantities of water, it also brought the greatest loss of protozoan parasites. For elution and centrifugation, both the membrane filter with hand‐kneading and Envirochek capsule with wrist‐action shaking attained higher recovery efficiencies for cysts and oocysts, Immunomagnetic separation (IMS), the purification procedure in Method 1623, had a much higher recovery efficiency for both Giardia and Cryptosporidium than the Percoll‐sucrose density gradient purification, which was the flotation procedure of the Information Collection Requirements Rule (ICR) protozoan method. Recovery efficiencies of IMS were 78.6% (SD = 13.7%) and 69.3% (SD = 13.3%) for cysts and oocysts, respectively, in contrast to the 22.7% (SD = 14.5%) for cysts and 29.9% (SD = 20.3%) for oocysts by using Percoll‐sucrose density gradient purification. In general, Giardia cysts attained a higher recovery efficiency. The recovery efficiencies of Method 1623, due to the use of Envirochek capsule filtration combined with the IMS, were 48.0% and 37.2% higher for Giardia and Cryptosporidium, respectively, than the ICR protozoan method for the three types of water.
Effects of Soil Amendments on the Bioavailability of Lead, Zinc, and Cadmium to Earthworms
Authors: Pearson Mark S. , Maenpaa Kimmo , Pierzynski Gary M. , Lydy Michael J.
Published: July 2010

This research investigated the effectiveness of phosphorus (P) and organic matter (OM) as possible in situ remediation techniques for metal contaminated soils. The study was designed to determine the bioavailability of Pb, Zn, and Cd individually and in combination to the earthworm Eisenia fetida in an artificial soil amended with varying levels of P and OM. A toxicokinetic approach using bioaccumulation factors and uptake rate coefficients was used to assess the bioavailability of the heavy metals. Overall, earthworms in P‐amended soils showed significantly reduced Pb levels in the individual and mixture experiments, while Zn and Cd bioavailability was not reduced. X‐ray diffraction analyses indicated that pyromorphites were formed with P amendment, thereby reducing the solubility and bioavailability of Pb within the soil. In contrast, the OM soil amendments increased bioavailability of Pb in the individual experiment and decreased it in the mixture experiment. The results of this study suggest that P amendments may be a viable technique to remediate Pb contaminated residential soils and that earthworm bioassays represent a biologically relevant measure of metal availability in soil.
Mobility of Soil Nitrogen and Microbial Responses following the Sudden Death of Established Turf
Authors: Jiang Zhongchun , Bushoven John T. , Ford Heather J. , Sawyer Carl D. , Amador José A. , Hull Richard J.
Published: July 2010

The stability of nitrogen within a turf‐soil ecosystem is important both for efficient turf management and preventing the contamination of ground water by nitrate. The objective of this study was to quantify responses of the microbial community and the mobility of soil nitrogen following the sudden death of established turf. Twelve‐year‐old turf plots comprising four cool‐season turfgrass species fertilized with five N sources were maintained on an Enfield silt loam (coarse‐silty over sandy or sandy‐skeletal, mixed, active, mesic Typic Dystrudept) at Kingston, RI. Half of the plots were killed with glyphosate in early September and any regrowth was removed mechanically. Measurements of soil physical, chemical, and microbiological properties and nitrate leaching in killed and healthy plots were compared for 12 mo. Turf death did not alter soil moisture, temperature, pH, or extractable ammonium. Nitrate levels were higher in both the root zone and at 60 cm following turf death and this difference persisted for the sampling year. Carbon mineralization and microbial biomass C were not different between soils from healthy and killed plots. Killed plots leached three times more nitrate than healthy plots but this amounted to less than 10% of total soil N present. Retention of nitrate in a turf‐soil system depends on absorption by living grass roots, although reasonable N stability is also provided by N cycling within the soil microbiota. Protecting ground water from nitrate contamination is optimized by maintaining a vigorous turfgrass cover.
Stabilization of Soil Nitrate by Reseeding with Perennial Ryegrass following Sudden Turf Death
Authors: Bushoven John T. , Jiang Zhongchun , Ford Heather J. , Sawyer Carl D. , Hull Richard J. , Amador José A.
Published: July 2010

Turf death can result in the mineralization of organic nitrogen (N) within the turf‐soil ecosystem. If not reestablished within 12 mo, dead turf can leach 10% of its total soil N as nitrate into ground water. This study investigated how rapidly and completely soil N can be restabilized following reseeding of killed turf. Twelve‐year‐old field plots, comprising four cool‐season turfgrass species growing on an Enfield silt loam (coarse‐silty over sandy‐skeletal, mixed, active, mesic Typic Dystrudepts) at Kingston, RI, were used. In early September 1997, one‐half of the plots were killed by applying glyphosate and three‐fourths of the dead plots were reseeded with ‘Palmer III’ perennial ryegrass (Lolium perenne L.) in late March 1998. Soil moisture, temperature, pH, respiration, and extractable nitrate and ammonium were monitored every 6 to 8 wk. Nitrate levels in subsoil water were monitored at 2‐wk intervals and nitrate leaching estimated for each percolation event. Reseeding enhanced soil respiration, within 6 wk of seeding, to levels comparable with those of soil in healthy plots. Surface soil nitrate levels in killed and reseeded plots declined within 6 wk of reseeding. Nitrate levels in soil water beneath the root zone declined in reseeded plots relative to those of healthy plots (9 mg NO3‐N L−1) within 8 wk of reseeding. Nitrate leaching also declined 3 mo after seeding to rates less than half of those from turf that had been killed but not reseeded. Our results indicate that the potential for increased nitrate leaching following turf death can be eliminated within 2 mo if the site is promptly reseeded.