bluuebunny/crossref_metadata_2025 huggingface dataset:
Competitive Degradation between the Fumigants Chloropicrin and 1,3‐Dichloropropene in Unamended and Amended Soils
Authors: Zheng Wei , Papiernik Sharon K. , Guo Minxing , Yates Scott R.
Published: June 2010

The mixture of 1,3‐dichloropropene (1,3‐D) and chloropicrin (CP) is used as a preplant soil fumigant. In comparison with individual fumigants, application of a mixture may affect the environmental dissipation and fate of each chemical, such as emission and degradation. We investigated the degradation of CP, 1,3‐D, and their mixture in fresh soils and sterile soils, and evaluated the competitive characteristic of fumigants in the mixture. The degradation of low concentrations of CP in fresh soil was accelerated at early times in the presence of 1,3‐D, whereas the addition of CP reduced the degradation rate of trans‐1,3‐D, possibly by inhibiting the activity of trans‐1,3‐D degrading microorganisms. The potential of applying amendments to the soil to increase the rate of CP and 1,3‐D degradation was also illustrated. The degradation of both fumigants was significantly enhanced in soils amended with ammonium thiosulfate (ATS) and sodium diethyldithiocarbamate (Na‐DEDTC) compared with unamended soil. Competitive degradation was observed for CP in amended soils in the presence of 1,3‐D. The degradation of cis‐1,3‐D in amended soils spiked as a mixture of 1,3‐D and CP was repressed compared with the rate of degradation in samples spiked with 1,3‐D only. This implied that in abiotic degradation, CP and cis‐1,3‐D competed for a limited number of reaction sites in amended soil, resulting in decreased degradation rates. No significant influence of fumigant mixtures was observed for trans‐1,3‐D in amended soil.
Organic Manure and Urea Effect on Metolachlor Transport through Packed Soil Columns
Authors: Singh Neera
Published: June 2010

Application of organic manure (OM) amendments and nitrogen fertilizers can affect the sorption and movement of pesticides in soil. This study summarizes the sorption and leaching of metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylphenyl)acetamide] in soils after cow (Bos taurus) manure (2.5 and 5.0%) and urea (60 and 120 kg N ha−1) amendments in batch and column experiments. Both cow manure and urea applications increased metolachlor sorption in soils. The values of the Freundlich adsorption parameter Kf(1/n) for treatments T0, T1 (OM), and T2 (OM) were 2.31, 3.32, and 3.96 in Soil 1; 2.02, 2.77, and 3.32 in Soil 2; and 1.10, 1.46, and 2.02 in Soil 3, respectively. Similarly, Kf(1/n) values for treatment T1 (urea) and T2 (urea) were 2.37 and 2.84 in Soil 1; 2.16 and 2.83 in Soil 2; and 1.50 and 1.70 in Soil 3, respectively. Column leaching studies using Soil 1 indicated that OM application drastically reduced the metolachlor leaching losses from 50% (natural soil) to <1.0% (5.0% OM amendment). Likewise, urea application also decreased metolachlor mobility and leaching losses in columns treated with 60 and 120 kg N ha−1 urea were 33 and 20%, respectively. The reduction in the metolachlor leaching losses was achieved through the increase in the sorption capability of the OM‐ and urea‐amended soil. Therefore, coapplication of metolachlor with cow manure or urea fertilizers will not enhance metolachlor mobility and reduces metolachlor leaching losses in low‐organic‐matter soil.
Stream Transport of Herbicides and Metabolites in a Tile‐Drained, Agricultural Watershed
Authors: David Mark B. , Gentry Lowell E. , Starks Karen M. , Cooke Richard A.
Published: June 2010

The occurrence of metabolites of many commonly used herbicides in streams has not been studied extensively in tile‐drained watersheds. We collected water samples throughout the Upper Embarras River watershed [92% corn, Zea mays L., and soybean, Glycine max (L.) Merr.] in east‐central Illinois from March 1999 through September 2000 to study the occurrence of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine), metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(methoxy‐1‐methylethyl) acetamide], alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide], acetochlor [2‐chloro‐N‐(ethoxymethyl)‐N‐(2‐ethyl‐6‐methylphenyl) acetamide], and their metabolites. River water samples were collected from three subwatersheds of varying tile density (2.8–5.3 km tile km−2) and from the outlet (United States Geological Survey [USGS] gage site). Near‐record‐low totals for stream flow occurred during the study, and nearly all flow was from tiles. Concentrations of atrazine at the USGS gage site peaked at 15 and 17 μg L−1 in 1999 and 2000, respectively, and metolachlor at 2.7 and 3.2 μg L−1; this was during the first significant flow event following herbicide applications. Metabolites of the chloroacetanilide herbicides were detected more often than the parent compounds (evaluated during May to July each year, when tiles were flowing), with metolachlor ethanesulfonic acid [2‐[(2‐ethyl‐6‐methylphenyl)(2‐methoxy‐1‐methylethyl)amino]‐2‐oxoethanesulfonic acid] detected most often (>90% from all sites), and metolachlor oxanilic acid [2‐[(2‐ethyl‐6‐methylphenyl)(2‐methoxy‐1‐methylethyl)amino]‐2‐oxoacetic acid] second (40–100% of samples at the four sites). When summed, the median concentration of the three chloroacetanilide parent compounds (acetochlor, alachlor, and metolachlor) at the USGS gage site was 3.4 μg L−1, whereas it was 4.3 μg L−1 for the six metabolites. These data confirm the importance of studying chloroacetanilide metabolites, along with parent compounds, in tile‐drained watersheds.
Irrigated Mountain Meadow Fertilizer Application Timing Effects on Overland Flow Water Quality
Authors: White Shawn K. , Brummer Joe E. , Leininger Wayne C. , Frasier Gary W. , Waskom Reagan M. , Bauder Troy A.
Published: June 2010

Nonpoint‐source pollution from agricultural activities is currently the leading cause of degradation of waterways in the United States. Applying best management practices to flood‐irrigated mountain meadows may improve agricultural runoff and return flow water quality. Prior research has focused on fertilizer use for increased hay yields, while few studies have investigated the environmental implications of this practice. We examined the effects of fertilizer application timing on overland flow water quality from an irrigated mountain meadow near Gunnison, Colorado. Application of 40 kg phosphorus (P) and 19 kg nitrogen (N) ha−1 using monoammonium phosphate (11–52–0, N–P–K) fertilizer to plots in the fall significantly reduced concentrations of reactive P and ammonium N in irrigation overland flow compared with early or late spring fertilization. Reactive P loading was 9 to almost 16 times greater when fertilizer was applied in the early or late spring, respectively, compared with in the fall. Ammonium N followed a similar trend with early spring loading more than 18 times greater and late spring loading more than 34 times greater than loads from fall‐fertilized plots. Losses of 45% of the applied P and more than 17% of the N were measured in runoff when fertilizer was applied in the late spring. These results, coupled with those from previous studies, suggest that mountain meadow hay producers should apply fertilizer in the fall, especially P‐based fertilizers, to improve hay yields, avoid economic losses from loss of applied fertilizers, and reduce the potential for impacts to water quality.
Speciation of Phosphorus in Phosphorus‐Enriched Agricultural Soils Using X‐Ray Absorption Near‐Edge Structure Spectroscopy and Chemical Fractionation
Authors: Beauchemin Suzanne , Hesterberg Dean , Chou Jeff , Beauchemin Mario , Simard Régis R. , Sayers Dale E.
Published: June 2010

Knowledge of phosphorus (P) species in P‐rich soils is useful for assessing P mobility and potential transfer to ground water and surface waters. Soil P was studied using synchrotron X‐ray absorption near‐edge structure (XANES) spectroscopy (a nondestructive chemical‐speciation technique) and sequential chemical fractionation. The objective was to determine the chemical speciation of P in long‐term‐fertilized, P‐rich soils differing in pH, clay, and organic matter contents. Samples of three slightly acidic (pH 5.5–6.2) and two slightly alkaline (pH 7.4–7.6) soils were collected from A or B horizons in two distinct agrosystems in the province of Québec, Canada. The soils contained between 800 and 2100 mg total P kg−1 Distinct XANES features for Ca‐phosphate mineral standards and for standards of adsorbed phosphate made it possible to differentiate these forms of P in the soil samples. The XANES results indicated that phosphate adsorbed on Fe‐ or Al‐oxide minerals was present in all soils, with a higher proportion in acidic than in slightly alkaline samples. Calcium phosphate also occurred in all soils, regardless of pH. In agreement with chemical fractionation results, XANES data showed that Ca‐phosphates were the dominant P forms in one acidic (pH 5.5) and in the two slightly alkaline (pH 7.4–7.6) soil samples. X‐ray absorption near‐edge structure spectroscopy directly identified certain forms of soil P, while chemical fractionation provided indirect supporting data and gave insights on additional forms of P such as organic pools that were not accounted for by the XANES analyses.
On‐Farm Assessment of Biosolids Effects on Soil and Crop Tissue Quality
Authors: Shober Amy L. , Stehouwer Richard C. , Macneal Kirsten E.
Published: June 2010

Agronomic use of biosolids as a fertilizer material remains controversial in part due to public concerns regarding the potential pollution of soils, crop tissue, and ground water by excess nutrients and trace elements in biosolids. This study was designed to assess the effects of long‐term commercial‐scale application of biosolids on soils and crop tissue sampled from 18 production farms throughout Pennsylvania. Biosolids application rates ranged from 5 to 159 Mg ha−1 on a dry weight basis. Soil cores and crop tissue samples from corn (Zea mays L.), soybean (Glycine spp.), alfalfa (Medicago sativa L.), orchardgrass (Dactylis spp.) hay, and/or sorghum [Sorghum bicolor (L.) Moench] were collected for three years from georeferenced locations at each farm. Samples were tested for nutrients, trace elements, and other variables. Biosolids‐treated fields had more post–growing season soil NO3 and Ca and less soil K than control fields and there was some evidence that soil P concentrations were higher in treated fields. The soil concentrations of Cu, Cr, Hg, Mo, Mn, Pb, and Zn were higher in biosolids‐treated fields than in control fields; however, differences were ≤0.06 of the USEPA Part 503 cumulative pollutant loading rates (CPLRs). There were no differences in the concentrations of measured nutrients or trace elements in the crop tissue grown on treated or control fields at any time during the study. Commercial‐scale biosolids application resulted in soil trace element increases that were in line with expected increases based on estimated trace element loading. Excess NO3 and apparent P buildup indicates a need to reassess biosolids nutrient management practices.
Particulates, Not Plants, Dominate Nitrogen Processing in a Septage‐Treating Aerated Pond System
Authors: Hamersley M. Robert , Howes Brian L. , White David S.
Published: June 2010

In pond and wetland systems for wastewater treatment, plants are often thought to enhance the removal of ammonium and nitrogen through the activities of root‐associated bacteria. In this study, we examined the role of plant roots in an aerated pond system with floating plants designed to treat high‐strength septage wastewater. We performed both laboratory and full‐scale experiments to test the effect of different plant root to septage ratios on nitrification and denitrification, and measured the abundances of nitrifying bacteria associated with roots and septage particulates. Root‐associated nitrifying bacteria did not play a significant role in ammonium and total nitrogen removal. Investigations of nitrifier populations showed that only 10% were associated with water hyacinth [Eichhornia crassipes (Mart.) Solms] roots (at standard facility plant densities equivalent to 2.2 wet g roots L−1 septage); instead, nitrifiers were found almost entirely (90%) associated with suspended septage particulates. The role of root‐associated nitrifiers in nitrification was examined in laboratory batch experiments where high plant root concentrations (7.4 wet g L−1, representing a 38% net increase in total nitrifier populations over plant‐free controls) yielded a corresponding increase (55%) in the non‐substrate‐limited nitrification rate (Vmax). However, within the full‐scale septage‐treating pond system, nitrification and denitrification rates remained unchanged when plant root concentrations were increased to 7.1 g roots L−1 (achieved by increasing the surface area available for plants while maintaining the same tank volume). Under normal facility operating conditions, nitrification was limited by ammonium concentration, not nitrifier availability. Maximizing plant root concentrations was found to be an inefficient mechanism for increasing nitrification in organic particulate‐rich wastewaters such as septage.
Corer–Reactors for Contaminant Flux Measurement in Sediments
Authors: Jung R. F. , Jones D. R. , Batley G. E.
Published: June 2010

Design details and operating instructions are provided for a sediment corer that can be converted into a reactor for the measurement of the fluxes of contaminants from sediments to overlying waters. The corer–reactor permits measurements, under controlled laboratory conditions, on intact, largely undisturbed sediment cores, without significantly perturbing the physical and chemical conditions found in the field. The design can be constructed in‐house for around US$240 (A$400) (excluding motor and corer lid), making it a relatively inexpensive system.
The Effect of Five Forage Species on Transport and Transformation of Atrazine and Isoxaflutole (Balance) in Lysimeter Leachate
Authors: Lin C. H. , Lerch R. N. , Garrett H. E. , Johnson W. G. , Jordan D. , George M. F.
Published: June 2010

A field lysimeter study with bare ground and five different ground covers was established to evaluate the effect of forage grasses on the fate and transport of two herbicides in leachate. The herbicides were atrazine (ATR; 2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine) and isoxaflutole [IXF; 5‐cyclopropyl‐4‐(2‐methylsulfonyl‐4‐trifluormethyl‐benzoyl)isoxazole], which has the commercial name Balance (Aventis Crop Science, Strasbourg, France). The ground covers included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.), and switchgrass (Panicum virgatum L.). The results suggested that the total IXF (parent + metabolites) showed higher mobility than ATR and its metabolites. Differences in the timing of transport reflected the rapid degradation of IXF to the more soluble, stable, and biologically active diketonitrile (DKN) metabolite in the system. Although grass treatments did not promote the hydrolysis of DKN, they significantly reduced its transport in the leachate through enhanced evapotranspiration. Grass treatments significantly enhanced ATR degradation in the leachates and soils, especially through N dealkylation, but they did not reduce total ATR transported in the leachate. Leachate from the orchardgrass lysimeters contained the highest proportion of ATR metabolites (64.2%). Timothy and smooth bromegrass treatments also displayed a significant increase in ATR metabolites in leachate. Grass‐treated lysimeters showed higher microbial biomass carbon than bare ground. For ATR treatments, the proportion of metabolites in the leachate strongly correlated with the elevated soil microbial biomass carbon in forage treatments. In contrast, DKN degradation was poorly correlated with soil microbial biomass carbon, suggesting that DKN degradation is an abiotic process.
Role of Mycorrhizal Fungi and Phosphorus in the Arsenic Tolerance of Basin Wildrye
Authors: Knudson J. A. , Meikle T. , DeLuca T. H.
Published: June 2010

Revegetation of arsenic (As)‐rich mine spoils is often impeded by the lack of plant species tolerant of high As concentrations and low nutrient availability. Basin wildrye [Leymus cinereus (Scribner & Merr.) A. Löve] has been observed to establish naturally in soils with elevated As content and thus may be useful for the stabilization of As‐contaminated soils. An experiment was conducted to evaluate how variable phosphorus (P) concentrations and inoculation with site‐specific arbuscular mycorrhizal fungi influence As tolerance of basin wildrye. Basin wildrye was grown in sterile sand in the greenhouse for 16 weeks. Pots of sterile sand were amended to create one of four rates of As (0, 3, 15, or 50 mg As kg−1), two rates of P (3 or 15 mg P kg−1), and ±mycorrhizal inoculation in a 2 × 4 × 2 factorial arrangement. After 16 weeks of growth, plants were harvested, shoots and roots thoroughly washed, and the tissue analyzed for total shoot biomass, total root and shoot As and P concentrations, and degree of mycorrhizal infection. Basin wildrye was found to be tolerant of high As concentrations allowing for vigorous plant growth at application levels of 3 or 15 mg As kg−1 Arsenic was sequestered in the roots, with 30 to 50 times more As in the roots than shoots under low P conditions. Mycorrhizal infection did not confer As tolerance in basin wildrye nor did mycorrhizal fungi influence biomass production. Phosphorus concentrations of 15 mg kg−1 effectively inhibited As accumulation in basin wildrye. Basin wildrye has the potential to be used for stabilization of As‐rich soils while minimizing exposure to grazing animals following reclamation.
Light‐Catalyzed Chromium(VI) Reduction by Organic Compounds and Soil Minerals
Authors: Tzou Y. M. , Loeppert R. H. , Wang M. K.
Published: June 2010

Detoxification of Cr(VI) through reduction has been considered an effective method for reclaiming Cr‐contaminated soil, sediment, and waste water. Organic matter is widely distributed in soil and aquatic systems; however, low Cr(VI) reduction rates inhibit the adoption of Cr reduction technologies by industry. Scientists have been aware of Cr(VI) reduction catalyzed by soil minerals; however, most of the studies focused on using semiconductors as catalysts with UV irradiation to accelerate the redox reactions. The objective of this study was to evaluate the rates of Cr(VI) reduction by fluorescence light in the presence of organic materials with or without specific soil minerals. Experimental results showed that dissolved organic compounds reduced Cr(VI) slowly under laboratory light; however, Cr(VI) reduction was greatly enhanced when growth chamber light was applied. Low photon flux (i.e., laboratory light) only enhanced Cr(VI) reduction by organics when Fe(III) was also present, because the Fe(II)–Fe(III) redox couple accelerated electron transfer and decreased electrostatic repulsion between reactants. Laboratory light was required to initiate Cr(VI) reduction catalyzed by TiO2; nonetheless, light‐catalyzed Cr(VI) reduction by smectite and ferrihydrite could occur only when greater light energy was provided with a growth chamber light. Our results suggest a potential pathway for Cr(VI) reduction using naturally occurring organic compounds and colloids in acidic water systems or in surface soils when light is available.
Compartmentalization of Metals within the Diverse Colloidal Matrices Comprising Activated Sludge Microbial Flocs
Authors: Leppard Gary G. , Droppo Ian G. , West M. Marcia , Liss Steven N.
Published: June 2010

Activated sludge floc from a wastewater treatment system was characterized, with regard to principal structural, chemical, and microbiological components and properties, in relation to contaminant–colloid associations and settling. Multiscale analytical microscopies, in conjunction with multimethod sample preparations, were used correlatively to characterize diverse colloidal matrices within microbial floc. Transmission electron microscopy, in conjunction with energy dispersive spectroscopy (EDS), revealed specific associations of contaminant heavy metals with individual bacterial cells and with extracellular polymeric substances (EPS). Floc structure was mapped from the level of gross morphology down to the nano‐scale, and flocs were described with respect to settling properties, size, shape, density, porosity, bound water content, and EPS chemical composition; gross surface properties were also measured for correlation with principal floc features. Compartmentalization results based on 171 EDS analyses and representative high‐resolution images showed that nano‐scale agglomerations of (i) silver (100%) and (ii) zinc (91%) were confined almost entirely to EPS matrices while (iii) Pb (100%) was confined to intracellular granules and (iv) aluminum was partitioned between EPS matrices (41%) and intracellular matrices (59%). The results suggest that engineered changes in microbial physiology and/or in macromolecular EPS composition may influence metal removal efficiencies.
Major and Trace Elements of Selected Pedons in the USA
Authors: Burt R. , Wilson M. A. , Mays M. D. , Lee C. W.
Published: June 2010

Few studies of soil geochemistry over large geographic areas exist, especially studies encompassing data from major pedogenic horizons that evaluate both native concentrations of elements and anthropogenically contaminated soils. In this study, pedons (n = 486) were analyzed for trace (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) and major (Al, Ca, Fe, K, Mg, Na, P, Si, Ti, Zr) elements, as well as other soil properties. The objectives were to (i) determine the concentration range of selected elements in a variety of U.S. soils with and without known anthropogenic additions, (ii) illustrate the association of elemental source and content by assessing trace elemental content for several selected pedons, and (iii) evaluate relationships among and between elements and other soil properties. Trace element concentrations in the non‐anthropogenic dataset (NAD) were in the order Mn > (Zn, Cr, Ni, Cu) > (Pb, Co) > (Cd, Hg), with greatest mean total concentrations for the Andisol order. Geometric means by horizon indicate that trace elements are concentrated in surface and/or B horizons over C horizons. Median values for trace elements are significantly higher in surface horizons of the anthropogenic dataset (AD) over the NAD. Total Al, Fe, cation exchange capacity (CEC), organic C, pH, and clay exhibit significant correlations (0.56, 0.74, 0.50, 0.31, 0.16, and 0.30, respectively) with total trace element concentrations of all horizons of the NAD. Manganese shows the best inter‐element correlation (0.33) with these associated total concentrations. Total Fe has one of the strongest relationships, explaining 55 and 30% of the variation in total trace element concentrations for all horizons in the NAD and AD, respectively.
Soil Phosphorus, Management Practices, and Their Relationship to Phosphorus Delivery in the Iowa Clear Lake Agricultural Watershed
Authors: Klatt J. G. , Mallarino A. P. , Downing J. A. , Kopaska J. A. , Wittry D. J.
Published: June 2010

Clear Lake is on Iowa's list of impaired water bodies because of high P concentration. This study assessed soil‐test phosphorus (STP), management practices, and P loads from its agricultural watershed. Management practice histories and STP for eight basins were surveyed in 1999. Soil samples (15‐cm depth) were analyzed for STP with agronomic [Bray P1 (BP), Olsen (OP), Mehlich 3 (M3P)] and environmental [iron oxide–impregnated paper (FeP) and water extraction (WP)] tests. Total phosphorus (TP) concentrations in water discharge from five basins were measured during two years, and TP loads were measured for two basins. The agronomic P tests showed that 46 to 83% (depending on the test) of the area tested above optimum for crops. Correlations among tests were high for OP, M3P, and FeP (r > 0.96) and lower for BP and WP (r = 0.88–0.93). Moldboard‐ and chisel‐plow tillage predominated (82% of the area). Applied P (mainly fertilizer) averaged 15 kg P ha−1 yr−1, and 40% of the high‐testing area (M3P test) was being fertilized. The mean annual water TP concentration across five basins was 275 to 474 μg L−1 The two‐year mean TP loads for the two gauged basins were 1504 and 1510 g P ha−1 yr−1 Water TP concentration increased linearly with increasing STP. Relationships were stronger for M3P and FeP (R2 = 0.96–0.97 for annual means and 0.77–0.79 for storm‐flow events) than for BP or WP (R2 = 0.88–0.91 and 0.59–0.69, respectively). Improving P and soil conservation practices in high‐testing areas could reduce P loads to the lake.
Simulating Pesticide Leaching and Runoff in Rice Paddies with the RICEWQ–VADOFT Model
Authors: Miao Zewei , Cheplick Mark J. , Williams Martin W. , Trevisan Marco , Padovani Laura , Gennari Mara , Ferrero Aldo , Vidotto Francesco , Capri Ettore
Published: June 2010

There is a current need to simulate leaching and runoff of pesticide from rice (Oryza sativa L.) paddies for assessing environmental impacts on a valuable agricultural system. The objective of this study was to develop a model for determining predicted environmental concentration (PEC) in soil, runoff, and ground water through the linkage of two models, rice water quality model (RICEWQ) and vadose zone transport model (VADOFT), to simulate pesticide fate and transport within a rice paddy and underlying soil profile. Model performance was evaluated with a field data set obtained from a 2‐yr field experiment in 1997 and 1998 in northern Italy. The predictions of amount of pesticide running off from the paddy field and accumulating in the paddy sediment were in agreement with measured values. Leaching into the vadose zone accounted for approximately 19% of the applied dose, but only a small amount of chemical (<0.1%) was predicted to reach ground water at a 5‐m depth due to sorption and transformation in the soil. The permeability of the soil and the water management practices in the paddy field were shown to have a strong influence on pesticide fate. These factors need to be well characterized in the field if model predictions are to be successful. The combined model developed in this work is an effective tool for exposure assessments for soil, surface water, and ground water, in the particular conditions of rice cultivation.
Phenols and Flavonoids in Aleppo Pine Needles as Bioindicators of Air Pollution
Authors: Robles Christine , Greff Stéphane , Pasqualini Vanina , Garzino Suzanne , Bousquet‐Mélou Anne , Fernandez Catherine , Korboulewsky Nathalie , Bonin Gilles
Published: June 2010

The aim of the present study is to assess whether certain ecophysiological responses (contents of total phenols, total proanthocyanidins, and total and simple flavonols), in the needles of Aleppo pines (Pinus halepensis Mill.) may be valid bioindicators for the assessment of the air quality. Samples were taken at five natural sites polluted by various pollutants (NO, NO2, other NOx, SO2, and O3). The results show a decrease in total phenol concentrations with levels of nitrogen oxide pollutions (significant negative correlations between the total phenol concentrations and concentrations of NO, NO2, and other NOx). Total flavonoids (total flavonols and proanthocyanidins) are useful bioindicators for ozone pollution (significant negative correlations between total proanthocyanidins and the concentrations of ozone and significant positive correlations between total flavonols and the ozone pollution). Sulfur dioxide pollution is distinguished by low concentrations in quercetin, isorhamnetin, and kaempferol (significant negative correlations between these simple flavonols and the concentrations of SO2). This work confirms the strong interest of using the phenolic compounds of Pinus halepensis as biological indicators of air quality.
Uptake and Release of Cesium‐137 by Five Plant Species as Influenced by Soil Amendments in Field Experiments
Authors: Fuhrmann Mark , Lasat Mitch , Ebbs Stephen , Cornish Jay , Kochian Leon
Published: June 2010

Phytoextraction field experiments were conducted on soil contaminated with 0.39 to 8.7 Bq/g of 137Cs to determine the capacity of five plant species to accumulate 137Cs and the effects of three soil treatments on uptake. The plants tested were redroot pigweed (Amaranthus retroflexus L. var. aureus); a mixture of redroot pigweed and spreading pigweed (A. graecizans L.); purple amaranth (A. cruteus L.) × Powell's amaranth (A. powellii S. Watson), referred to here as the amaranth hybrid; Indian mustard [Brassica juncea (L.) Czern.]; and cabbage (Brassica oleracea L. var. capitata). For control plants, the concentration ratios (CR) of 137Cs were greatest for redroot pigweed and the amaranth hybrid, with average CR values of 1.0 ± 0.24 and 0.95 ± 0.14, respectively. The lowest value was for Indian mustard at 0.36 ± 0.10. The soil treatments included (i) application of NH4NO3 solution to the soil after plants had matured, (ii) addition of composted manure to increase organic matter content of the soil, (iii) combination of the manure and ammonium solution treatments, and (iv) controls. The ammonium solution gave little overall increase in accumulation of 137Cs. The use of composted manure also had little influence, but the combination of the composted manure with application of ammonium solutions had a distinctly negative effect on plant uptake of 137Cs. On average the fraction of 137Cs taken up from the soil was reduced by 57.4 ± 1.2% compared with controls. This was the result of release of competing ions, primarily Ca, from the manure and was observed across all five plant species tested. The application of ammonium solution took place in the last two weeks before harvest. The reduction of plant 137Cs content, by addition of the ammonium solution, as it interacted with the manure, indicates that substantial quantities 137Cs can be released from the shoots of plants as a result of sudden changes in soil solution chemistry.
Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment
Authors: Smith R. V. , Lennox S. D. , Bailey J. S.
Published: June 2010

An upward trend in soluble reactive phosphorus (SRP) concentrations in Northern Ireland rivers leading to increased eutrophication has been reported for the last two decades. To identify if a similar trend could be observed in land drainage waters SRP and other P fractions were measured weekly from 1989 to 1997 in land drainage from a 9‐ha grassland catchment in Northern Ireland that had a mean P surplus applied of 23.4 kg P ha−1 yr−1 Regressions of annual median concentrations of P fractions in land drainage waters against time for 1989 through to 1997 showed significant increases of SRP and soluble unreactive phosphorus (SUP) of 2.4 and 1.2 μg P L−1 yr−1, respectively. However, the annual flow‐weighted concentrations and loads of all P fractions did not show significant increases with time. During the period 1998–2000 a change of management was introduced when only maintenance dressings of P were applied to the catchment according to Ministry of Agriculture, Fisheries and Food guidelines. This resulted in significant reductions in SRP concentrations in 2000 compared with 1997.
Aluminum Effect on Dissolution and Precipitation under Hyperalkaline Conditions
Authors: Qafoku Nikolla P. , Ainsworth Calvin C. , Szecsody James E. , Qafoku Odeta S.
Published: June 2010

Substantial amounts of self‐boiling, Al‐rich, hyperalkaline, and saline high‐level waste fluids (HLWF) were deposited to the vadose zone at the Hanford Site, in Washington State. The objective of this study was to investigate the effects of similar fluids on the extent of dissolution and precipitation in the sediments. Metal‐ and glass‐free systems were used to conduct batch experiments at 323 K under CO2 and O2 free conditions. Base‐induced dissolution of the soil minerals was rapid in the first 48 h as indicated by immediate releases of Si and Fe into the soil solution. Potassium release lagged behind and dissolution of K‐bearing minerals (mica and K‐feldspar) proceeded faster only after 2 to 3 d of the experiment. Silicon and Fe release exhibited high dependence on aqueous [Al] (rate orders <−1), because Al decreased free OH concentration in the contact solution and probably inhibited soil mineral dissolution. Initial K release exhibited low dependence on [Al] (fractional rate orders). Initial dissolution rates calculated based on Si release varied with aqueous [Al] from 29.47 to 4.35 × 10−12 mol m−2 s−1 Aluminum participated in the formation of the secondary phases (precipitation rates of 10−8 mol s−1) but the overall precipitation rate of alumino‐silicate secondary phases was probably controlled by aqueous [Si] (rates of 10−9, and rate constants between 0.0054 and 0.0084 h−1). The changes in the soil solution chemistry (release of K, Si, Fe, and other elements) may play a significant role in the fate of radionuclides and contaminants like Cs, Sr, Cr, and U in the Hanford sediments.
An Integrated Chemical, Thermal, and Microbiological Approach to Compost Stability Evaluation
Authors: Mondini Claudio , Dell'Abate Maria Teresa , Leita Liviana , Benedetti Anna
Published: June 2010

The evaluation of compost stability is of the utmost importance for the reliability of composting as a recycling strategy. To date there is no single parameter that can give a sure indication of the stability of composts from different starting materials. This paper investigates different methods of evaluating the dynamics of transformation of materials and the stability level of the end products in a composting process. The following parameters were determined on compost samples of different ages from cotton (Gossypium herbaceum L.) cardings and yard wastes: humification index (HI), degree of humification (DH), thermogravimetry (TG) microbial biomass C (BC), and ninhydrin‐reactive N (BNIN). Finally, from TG, derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC) thermal stability parameters were deduced. Humification parameters in the end products (0.2 and 81% for HI and DH, respectively) showed the effective stability reached by the organic matter (OM). Thermal analysis evidenced the presence of two main organic pools with different thermal stability. During composting a relative increase in the more stable organic pool was indicated by the variation of the thermostability index R1 from 0.41 to 0.74. The parameter R1 was significantly correlated with both HI (r = −0.94; P < 0.05) and DH (r = 0.97; P < 0.05). Microbial biomass content dynamics reflected the availability of readily decomposable substrates. The ratio between BNIN and total N in the end product was 0.96%, indicating a good stability level. The simultaneous application of different approaches, considering different properties of composting materials, provides a more complete description of the stability and quality reached by the organic materials.
Water‐Quality Effects of Incorporating Poultry Litter into Perennial Grassland Soils
Authors: Pote D. H. , Kingery W. L. , Aiken G. E. , Han F. X. , Moore P. A. , Buddington K.
Published: June 2010

Poultry litter provides a rich source of nutrients for perennial forages, but the usual practice of surface‐applying litter to pastures can degrade water quality by allowing nutrients to be transported from fields in surface runoff, while much of the NH4–N volatilizes. Incorporating litter into the soil can minimize such problems in tilled systems, but has not been used for perennial forage systems. In this study, we minimized disturbance of the crop, thatch, and soil structure by using a knifing technique to move litter into the root zone. Our objective was to determine effects of poultry litter incorporation on quantity and quality of runoff water. Field plots were constructed on a silt loam soil with well‐established bermudagrass [Cynodon dactylon (L.) Pers.] and mixed grass forage. Each plot had 8 to 10% slopes, borders to isolate runoff, and a downslope trough with sampling pit. Poultry litter was applied (5.6 Mg ha−1) by one of three methods: surface‐applied, incorporated, or surface‐applied on soil‐aeration cuts. There were six treatment replications and three controls (no litter). Nutrient concentrations and mass losses in runoff from incorporated litter were significantly lower (generally 80–95% less) than in runoff from surface‐applied litter. By the second year of treatment, litter‐incorporated soils had greater rain infiltration rates, water‐holding capacities, and sediment retention than soils receiving surface‐applied litter. Litter incorporation also showed a strong tendency to increase forage yield.
Nitrite Formation and Nitrous Oxide Emissions as Affected by Reclaimed Effluent Application
Authors: Master Y. , Laughlin R. J. , Stevens R. J. , Shaviv A.
Published: June 2010

The effect of irrigation with reclaimed effluent (RE) (after secondary treatment) on the mechanisms and rates of nitrite formation, N2O emissions, and N mineralization is not well known. Grumosol (Chromoxerert) soil was incubated for 10 to 14 d with fresh water (FW) and RE treated with 15NO3− and 15NH4+ to provide a better insight on N transformations in RE‐irrigated soil. Nitrite levels in RE‐irrigated soil were one order of magnitude higher than in FW‐irrigated soil and ranged between 15 to 30 mg N kg−1 soil. Higher levels of NO2− were observed at a moisture content of 60% than at 70% and 40% w/w. Nitrite levels were also higher when RE was applied to a relatively dry Grumosol (20% w/w) than at subsequent applications of RE to soil at 40% w/w. Isotopic labeling indicated that the majority of NO2− was formed via nitrification. The amount of N2O emitted from RE‐treated Grumosol was double the amount emitted from FW treatments at 60% w/w. Nitrification was responsible for about 42% of the emissions. The N2O emission from the RE‐treated bulk soil (passing a 9.5‐mm sieve) was more than double the amount formed in large aggregates (4.76–9.5 mm in diameter). No dinitrogen was detected under the experimental conditions. Results indicate that irrigation with secondary RE stimulates nitrification, which may enhance NO3− leaching losses. This could possibly be a consequence of long‐term exposure of the nitrifier population to RE irrigation. Average gross nitrification rate estimates were 11.3 and 15.8 mg N kg−1 soil d−1 for FW‐ and RE‐irrigated bulk soils, respectively. Average gross mineralization rate estimates were about 3 mg N kg−1 soil d−1 for the two water types.
Uncertainty and Sensitivity Analysis of Spatial Predictions of Heavy Metals in Wheat
Authors: Brus D. J. , Jansen M. J. W.
Published: June 2010

Heavy metals seriously threaten the health of human beings when they enter the food chain. Therefore, policymakers require precise predictions of heavy metal concentrations in agricultural crops. In this paper we quantify the uncertainty of regression predictions of Cd and Pb in wheat (Triticum aestivumL.) and the contributions to the uncertainties in these predictions associated with inputs to the regression model. For each node of the 500‐ × 500‐m grid covering the arable soils in the Netherlands, a latin hypercube sample size of 1000 is constructed from the uncertainty distributions of the explanatory variables (pH, soil organic matter [SOM], and heavy metal concentration in soil), the regression coefficients, and the random term of the regression model. This sample is used as input for the regression model to obtain 1000 values from the uncertainty distributions of the log(Cd) and log(Pb) concentration in wheat. There were no nodes where the recent EU quality standards for Cd and Pb (0.2 mg kg−1fresh wt.) in wheat were almost certain to be exceeded. For most nodes with clay soils, the quality standard for Cd in wheat almost certainly will not be exceeded; for Pb this is much less certain. The uncertainty in the Cd concentration in soil contributes most to the uncertainty in the predicted Cd concentrations in wheat (36% on the average), followed by the random term of the regression model (23%). For Pb the contribution of the random term is by far the largest (52%).
Polycyclic Aromatic Hydrocarbon Storage in a Typical Cerrado of the Brazilian Savanna
Authors: Wilcke Wolfgang , Krauss Martin , Lilienfein Juliane , Amelung Wulf
Published: June 2010

There may be important biological sources of polycyclic aromatic hydrocarbons (PAHs) to the global environment, particularly of naphthalene, phenanthrene, and perylene, that originate in the tropics. We (i) studied the distribution of PAHs among different compartments of a typical Cerrado to locate their sources and (ii) quantified the PAH storage of this ecosystem. The sum of 20 PAH (Σ20PAHs) concentrations ranged from 25 to 666 μg kg−1in plant tissue, 7.4 to 32 μg kg−1in litterfall, 206 to 287 μg kg−1in organic soil, and 10 to 79 μg kg−1in mineral soil. Among the living biomass compartments, the bark had the highest mean PAH concentrations and coarse roots the lowest, indicating that PAHs in the plants originated mainly from aboveground sources. Naphthalene and phenanthrene were the most abundant individual PAHs, together contributing 33 to 96% to the Σ20PAHs concentrations. The total storage of the Σ20PAHs in Cerrado was 7.5 mg m−2to a 0.15‐m soil depth and 49 mg m−2to a 2‐m soil depth. If extrapolated to the entire Brazilian Cerrado region, roughly estimated storages of naphthalene and phenanthrene correspond to 7300 and 400 yr of the published annual emissions in the United Kingdom, respectively. The storage of benzo[a]pyrene, a typical marker for fossil fuel combustion, in the Cerrado only corresponds to 0.19 yr of UK emissions. These results indicate that the Brazilian savanna comprises a huge reservoir of naphthalene and phenanthrene originating most likely from the aboveground parts of the vegetation or associated organisms. Thus, the Cerrado might be a globally important source of these PAHs.
Short‐ and Longer‐Term Effects of the Willow Root System on Metal Extractability in Contaminated Dredged Sediment
Authors: Vervaeke P. , Tack F. M. G. , Lust N. , Verloo M.
Published: June 2010

Willow (Salix spp.) stands are often proposed as vegetation covers for the restoration and stabilization of contaminated and derelict land. Planting willows on dredged sediment disposal sites for biomass production can be an alternative to traditional capping techniques. However, with the introduction of willow stands on dredged sediment disposal sites, the possibility of increased contaminant availability in the root zone must be acknowledged as it can increase the risk of leaching. Two trials investigated the availability of Cd, Zn, Cu, and Pb in the root zones of willows grown on contaminated sediment. To assess the effects of willow root growth on metal extractability and mobility, bulk and rhizosphere sediment samples were extracted with deionized water, ammonium acetate at pH 7, and ammonium acetate–EDTA at pH 4.65. A rhizobox experiment was used to investigate the short‐term effect of willow roots on metal availability in oxic and anoxic sediment. Longer‐term effects were assessed in a field trial. The rhizobox trial showed that Cd, Zn, and Cu extractability in the rhizosphere increased while the opposite was observed for Pb. This was attributed to the increased willow‐induced oxidation rate in the root zone as a result of aeration and evapotranspiration, which masked the direct chemical and biological influences of the willow roots. The field trial showed that Cu and Pb, but not Cd, were more available in the root zone after water and ammonium acetate (pH 7) extraction compared with the bulk sediment. Sediment in the root zone was better structured and aggregated and thus more permeable for downward water flows, causing leaching of a fraction of the metals and significantly lower total contents of Cd, Cu, and Pb. These findings indicate that a vegetation cover strategy to stabilize sediments can increase metal availability in the root zone and that potential metal losses to the environment should be considered.
Overland and Near‐Surface Transport ofCryptosporidium parvumfrom Vegetated and Nonvegetated Surfaces
Authors: Trask Jennifer R. , Kalita Prasanta K. , Kuhlenschmidt Mark S. , Smith Ronald D. , Funk Ted L.
Published: June 2010

Understanding microbial pathogen transport patterns in overland flow is important for developing best management practices for limiting microbial transport to water resources. Knowledge about the effectiveness of vegetative filter strips (VFS) to reduce pathogen transport from livestock confinement areas is limited. In this study, overland and near‐surface transport ofCryptosporidium parvumhas been investigated. Effects of land slopes, vegetation, and rainfall intensities on oocyst transport were examined using a tilting soil chamber with two compartments, one with bare ground and the other with brome (Bromus inermisLeyss.) vegetation. Three slope conditions (1.5, 3.0, and 4.5%) were used in conjunction with two rainfall intensities (25.4 and 63.5 mm/h) for 44 min using a rainfall simulator. The vegetative surface was very effective in reducingC. parvumin surface runoff. For the 25.4 mm/h rainfall, the total percent recovery of oocysts in overland flow from the VFS varied from 0.6 to 1.7%, while those from the bare ground condition varied from 4.4 to 14.5%. For the 63.5 mm/h rainfall, the recovery percentages of oocysts varied from 0.8 to 27.2% from the VFS, and 5.3 to 59% from bare‐ground conditions. For all slopes and rainfall intensities, the total (combining both surface and near‐surface) recovery ofC. parvumoocysts was considerably less from the vegetated surface than those from the bare‐ground conditions. These results indicate that the VFS can be a best management practice for controllingC. parvumin runoff from animal production facilities.
Removal of Organic Matter and Nitrogen from River Water in a Model Floodplain
Authors: Chung Jong‐Bae , Kim Seung‐Hyun , Jeong Byeong‐Ryong , Lee Young‐Deuk
Published: June 2010

A significant improvement in river water quality cannot be expected unless nonpoint‐source contaminants are treated in addition to the further treatment of point‐source contaminants. If river water is sprayed over a floodplain, the consequent water filtration through the sediment profile can simultaneously remove organic matter and nitrogen in the water through aerobic and denitrifying reactions. This hypothesis was tested using lysimeters constructed from polyvinyl chloride (PVC) pipe (150 cm long, 15 cm in diameter) packed with loamy sand floodplain sediment. Water was applied to the top of the lysimeters at three different flow rates (48, 54, and 68 mm d−1). Concentrations of NO3 and dissolved oxygen (DO), chemical oxygen demand (COD), and redox potential (Eh) in the water were measured as functions of depth after the system reached steady states for both water flow and reactions. At the rate of 68.0 mm d−1, a reducing condition for denitrification developed below the 5‐cm depth due to the depletion of O2 by organic matter degradation in the surface oxidizing layer; Eh and DO were below 205 mV and 0.4 mg L−1, respectively. At a depth of 70 cm, COD and NO3–N concentration decreased to 5.2 and 3.8 mg L−1 from the respective influent concentrations of 17.1 and 6.2 mg L−1 Most biodegradable organic matter was removed during flow and further removal of NO3 was limited by the lack of an electron donor (i.e., organic matter). These results indicate that the floodplain filtration technique has great promise for treatment of contaminated river water.