HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Search for Related Content

EXECUTIVE SUMMARIES

This Issue in Journal of Environmental Quality

	Crust Formation Reduces Ammonia Emissions

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

	Methyl Bromide Air Concentration Predicted by Use

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
The exposure assessment of methyl bromide depends on estimation or measurement of its air concentrations. Li et al. (p. 420–428) propose a methodology for systematically exploring the empirical relationship between methyl bromide use intensity and ambient air concentrations. Monitored air concentrations were regressed to methyl bromide use over various spatiotemporal scales that step-wise increased around the monitoring site and monitoring period. Results showed the best fit was Y = 0.46 + 0.00120X (R² = 0.95, n = 11), where Y was the 8-wk average ambient air concentration (µg/m³) and X was the weekly average use (kg/wk) over an area of 11.3 x 11.3 km² (7 x 7 mile²). This model can be used in methyl bromide subchronic exposure assessment from field fumigation.

	Milk Production Intensity and Greenhouse Gas Emissions

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Livestock production is a major contributor to Ireland's greenhouse gas (GHG) emissions. Life cycle assessment methodology was used to compare GHG emission for Irish dairy units operating within an agri-environmental scheme and as conventional dairy units. Casey and Holden (p. 429–436) show that on average total emissions from conventional units were around 18% greater than the agri-environmental scheme units, while emissions per hectare were 17% greater but there was no significant difference in terms of emission per unit milk produced. In terms of the intensity of milk production, it was concluded that fewer cows producing more milk at lower stocking rates are required to achieve a national reduction in GHG emissions from Irish dairy production. Such a move would represent extensification in terms of area, but intensification in terms of animal husbandry.

	Tillage Affects Soil Carbon Dioxide Emission

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Intensive tillage systems can induce soil carbon dioxide (CO₂) emission and soil C loss. Al-Kaisi and Yin (p. 437–445) report that no-tillage and strip-tillage systems significantly increased total soil organic C at the 0- to 10-cm soil depths compared with chisel and moldboard plow tillage systems after 3 yr of tillage practices. Soil CO₂ release immediately after tillage operation with moldboard plow was significantly greater than that from conservation tillage systems. Cumulative soil CO₂ release from soil with conservation tillage systems was 19 to 41% less than moldboard plow tillage system. Adopting less intensive tillage systems such as no-tillage and strip-tillage are effective in reducing CO₂ emission, thus improving soil C sequestration in a corn–soybean rotation.

	Subirrigation Enhances Reduction of N2O to N2

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Water table management, consisting of free drainage and controlled drainage–subirrigation, is a beneficial practice that has been shown to improve drainage water quality by reducing nitrate pollution through enhanced denitrification. Denitrification is the major biological process by which nitrates are reduced to N₂, with nitrous oxide (N₂O) being an intermediary product. Whether nitrate removal by denitrification is beneficial to the wider environment depends on whether the dominant end product is N₂O or N₂. Elmi et al. (p 446–454) report on a 2-yr field-scale study during which total denitrification (N₂O + N₂), N₂O production, and N₂O to N₂O + N₂ ratios in subsurface environment (0–0.45 m) as influenced by water table management were quantified. Denitrification rates in the soil profile were generally greater under subirrigation than free drainage in most sampling dates. Ratios of N₂O to N₂O + N₂ were lower in subirrigation plots than free drainage, suggesting the subirrigation treatment created conditions that enhance further reduction of N₂O to N₂. It was concluded that higher denitrification rates under subirrigation than free drainage do not necessarily add to concerns over global atmospheric N₂O loadings as the majority of gaseous N would have been emitted as N₂ under our field conditions.

	Methane Oxidation Discovered in Slurry Storages

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Livestock manure is a significant source of atmospheric methane (CH₄), especially during liquid storage. Petersen et al. (p. 455–461) show that methane-oxidizing bacteria inhabit surface crusts of slurry storages and conclude that the process is a potentially important sink for methane produced during storage. Surface crust materials were sampled from experimental storages with cattle slurry or anaerobically digested cattle slurry. Methane was oxidized by extracts of surface crust material and by field-moist material, but not by autoclaved samples. Partial drying of surface crust samples stimulated methane oxidation. Methane oxidation rates were comparable with the activity in wetlands and rice paddies. Measures to ensure crust formation with or without a solid cover appear to be a cost-effective greenhouse gas mitigation option.

	Unraveling Complexities of Polycyclic Aromatic Hydrocarbon Degradation

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Polycyclic aromatic hydrocarbons, such as phenanthrene and naphthalene, are ubiquitous pollutants and can sometimes resist biodegradation. Phytooxidation is often listed as a cause of structural changes that can promote or inhibit biodegradation of these compounds. Holt et al. (p. 462–468) report that 9,10-phenanthrenequinone catalyzes its own formation as the main photoproduct of phenanthrene. This quinone also inhibits biodegradation of naphthalene, while phenanthrene itself does not. Finally, one phenanthrene-degrading enrichment culture degrades the quinone cometabolically. These behaviors of 9,10-phenanthrenequinone are even more interesting as they apply to complex mixtures such as creosote.

	Straining and Attachment of Oocysts

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Knowledge of the processes that control the movement and fate of pathogenic Cryptosporidium parvum oocysts is required to protect water supplies. Previous studies and models have neglected straining as a mechanism of oocyst deposition, and assumed that oocyst migration was controlled by attachment. Laboratory and mathematical modeling studies were undertaken by Bradford and Bettahar (p. 469–478) to examine mechanisms of oocyst transport and deposition in ground water systems. Results indicate that oocysts can also be retained in small pores due to straining. The ability of a mathematical model to describe oocyst transport in three sands was improved by inclusion of straining, attachment, and detachment.

	Desorption of Arsenate from Kaolinite

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Arsenic is highly toxic and therefore represents a potential threat to the environment and human health. The mobility and bioavailability of As in soil is mostly controlled by adsorption and desorption reactions. Quaghebeur et al. (p. 479–486) report that the amount of arsenate desorbed over time using a flow-through setup was higher in comparison with the amount desorbed over time using a traditional batch desorption setup. The pH had a large effect on the amount of arsenate desorbed from kaolinite, with both an increase and a decrease in pH (from the initial pH 6.4) enhancing arsenate desorption. Modelling desorption over time revealed that pH can influence arsenate desorption over extended periods of time.

	Selenium Removal by Zerovalent Iron

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Removal of Se from Se-contaminated water is important in protecting wetland wildlife. Zhang et al. (p. 487–495) used zerovalent Fe to remove selenate from water in the presence of varying concentrations of Cl^–, SO₄^2–, NO₃^–, HCO₃^–, and PO₄^3–. Under an open condition, zerovalent Fe effectively removed 100 and 93% of the added selenate in the 10 mM Cl^– and SO₄^2– solutions, respectively. Selenate was also removed from 5, 50, and 100 mM Cl^–; 1, 5, and 10 mM NO₃^–; 5, 50, and 100 mM SO₄^2–; 1, 5, and 10 mM HCO₃^–; and 1 and 5 mM PO₄^3– solutions during a 2-d experiment. This work suggests zerovalent Fe may be an effective agent to remove Se from Se-contaminated agricultural drainage water.

	Prediction of Metal Availability to Wheat

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
This is the first paper to investigate bioavailability of a suite of metals in soil simultaneously using such a comprehensive set of chemical techniques. It is also the first time the new technique of diffusive gradients in thin films (DGT) and the concept of effective concentration (C_E) have been used to assess Zn, Cd, Cu, and Pb availability to wheat. Nolan et al. (p. 496–507) found that Zn uptake is best predicted by DGT, Pb uptake by DGT and soil solution, Cd uptake by DGT and CaCl₂ extractable, and surprisingly Cu uptake by total Cu. The underlying processes that determine these findings are discussed.

	Copper Availability in Biosolids-Amended Israeli Soils

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Although having many potential benefits, land application of biosolids may pose a risk to the environment because the material commonly has high concentrations of heavy metals (with Cu being a major concern). It is therefore important to determine whether the practice will lead to Cu toxicity in the environment, particularly over the medium to long term when organic matter and other protective components in the biosolids may break down. Oliver et al. (p. 508–513) report that, even when applied at rates vastly exceeding current practices, the availability of Cu sourced from biosolids was low and stable, and did not increase over a 7-yr period. Therefore, current practices do not pose a significant risk to the environment in terms of Cu toxicity. The availability of Cu was monitored using isotopic dilution techniques.

	Lake Sediments Characterize Catchment Erosion

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Increasing concern for the problems of soil degradation and associated off-site sedimentation at the regional and global scale has highlighted the need for improved information on rates of soil loss and sediment sources and thus for new approaches to assembling such information. Zhang and Walling (p. 514–523) report how the Cs-137 content of sediment cores collected from lakes and reservoirs can be used to characterize surface erosion rates and the main sediment sources in the upstream catchment. The rate of decline of Cs-137 concentrations in the upper part of a sediment core provides valuable information on the rate of soil loss from the eroding areas of the upstream watershed. Equally, the magnitude of the Cs-137 concentrations in recently deposited sediment provides a means of assessing the relative importance of surface and channel, gully, and/or subsurface erosion in contributing to the sediment deposited in the lake or reservoir. The approach has been successfully tested using the Cs-137 profiles for sediment cores collected from lakes and reservoirs in areas representative of a wide range of erosion intensities.

	Ground Water Denitrification in Deep Riparian Wetland Soils

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
The contribution of riparian areas to the catchment-scale N budget is of great interest to researchers and land use managers. Kellogg et al. (p. 524–533) found that within two common geomorphic settings (i.e., glacial outwash and alluvial), riparian wetlands can remove substantial ground water nitrate at depths down to 3 m at sites located in permeable stratified sediments. Correlations of site characteristics with in situ ground water denitrification rates varied with depth below the soil surface. At 65 cm, ground water denitrification rates varied with factors associated with the surface ecosystem (temperature, dissolved organic C). At deeper depths, ground water denitrification rates were significantly higher closer to the stream where the subsoil often contains organically enriched deposits that indicate fluvial geomorphic processes, such as intermittent flooding events and stream meandering. High ground water denitrification rates observed in hydric soils down to 3 m within 10 m of the stream in both alluvial and glacial outwash settings argue for the importance of both types of riparian wetland settings as potential N sinks at the catchment scale.

	Herbicide Leaching in Tropical Soils

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Intensive application of organic chemicals to a newly irrigated sugarcane area in the semiarid western part of Reunion Island (France) has prompted local regulation agencies to question the potential to contaminate ground water resources. Bernard et al. (p. 534–543) used the simple attenuation factor approach to assess potential leaching of five herbicides through the vadose zone of two Inceptisols. Results show a lower risk of leaching in temperate regions due to the tropical conditions characterized by higher temperatures and an abundance of highly adsorbent soils. Potential leaching of the herbicides was found to be unlikely except during the raining period (December to mid-April) and especially 40 d within February and March when there is a 2.5% probability of recharge rates equal to or higher than 50 mm d^–1.

	New Insights into Chlordane Contamination

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Sediments are increasingly recognized as both carrier and potential source of contaminants in aquatic environments. Using linear regression and principal axis analysis, Ouyang et al. (p. 544–551) discovered that a linear correlation existed between -chlordane and total chlordane as well as between -chlordane and total chlordane, whereas no correlation existed between trans-nonachlor and total chlordane. A GIS-based kriging analysis showed that the Cedar River and the north end of the Ortega River in Florida, USA, had total sediment chlordane concentrations above the probable effect level (4.79 µg/kg), which could pose a potential risk to aquatic life.

	Hydrophobic Fractions Sorb Organic Compounds

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Dissolved organic matter (DOM) from wastewater can affect the sorption behavior of organic compounds in soils. Ilani et al. (p. 552–562) have tested the role of structural fractions of wastewater DOM in sorption of organic pollutants. For all sorbates, binding to the hydrophobic neutral (HoN) fractions was much higher than to the hydrophobic acid (HoA) fractions and bulk DOM. Higher sorption coefficients were exhibited by DOM samples containing a higher level of hydrophobic fractions (HoA + HoN), suggesting the sorption of hydrophobic organic compounds by DOM is governed by the level of these structural substances. Although the HoN fraction made up a relatively small portion of DOM (<10%) and is mainly composed from aliphatic moieties, it is a dominant sorbent, especially in DOM, which is characterized by low hydrophobicity.

	Phytase Does Not Increase Phosphorus Solubility

TOP Crust Formation Reduces Ammonia... Methyl Bromide Air Concentration... Milk Production Intensity and... Tillage Affects Soil Carbon... Subirrigation Enhances Reduction... Methane Oxidation Discovered in... Unraveling Complexities of... Straining and Attachment of... Desorption of Arsenate from... Selenium Removal by Zerovalent... Prediction of Metal Availability... Copper Availability in Biosolids... Lake Sediments Characterize... Ground Water Denitrification in... Herbicide Leaching in Tropical... New Insights into Chlordane... Hydrophobic Fractions Sorb... Phytase Does Not Increase... One Extraction Coefficient... Resuspension of Bacteria-Laden... Reducing Nitrate Losses to... Phosphorus Bioavailability... Leaching of Glyphosate and... Data Availability Affects... Effluent Treatment Differs... Feedlot Soil Composition... Feedlot Soil Composition Affects... Modeling Carbon and Nitrogen... Dry Coal Combustion Products... Dietary Changes Affect... Diet Affects Gaseous Emissions... Nitrate Removal in Riparian... Phosphorus Enrichment Triggers... Reservoir Sediments Release...

 
Poultry and swine growers routinely include phytase in dietary formulations. Phytase improves diet P availability by cleaving phytate bonds that are abundant in cereal grains typically fed to livestock. By cleaving the phytate bond, the cereal grain P can be absorbed by swine and poultry. However, this has raised the concern of whether or not phytase increases the solubility of excreted P, thereby increasing the risk for short-term environmental pollution. The goal of research by Angel et al. (p. 563–571) was to determine if phytase, when fed correctly with a concurrent reduction in dietary total phosphorus (TP), increased excreted water-soluble phosphorus (WSP) or if observed increases in WSP are due to microbial activity, post-excretion. Experiments were conducted with broiler chickens, turkeys, and swine. Incubation of excreta resulted in increased WSP, irrespective of phytase addition. Addition of antibiotics before incubation prevented the increase in WSP. Therefore, when phytase is used properly (i.e., with a simultaneous decrease in non-phytin P), WSP or WSP as a percent of TP are not affected. The increase in WSP as a percent of TP post-excretion is a function of excreta microbial activity a