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Accepted, edited articles are published here after author proofing to provide rapid publication and better access to the newest research in the Journal of Environmental Quality. Articles are compiled into bimonthly issues at dl.sciencesocieties.org/publications/jeq, which include the complete archive. Citation | Articles posted here are considered published and may be cited by the doi.

Maguire, R.O., P.J. A. Kleinman, C.J. Dell, D.B. Beegle, R.C. Brandt, J.M. McGrath, and Q.M. Ketterings. 2011. Manure application technology in reduced tillage and forage systems: A review. J. Environ. Qual. doi: 10.2134/jeq2009.0228

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Current issue: J. Environ. Qual. 44(4)



  • ATMOSPHERIC POLLUTANTS AND TRACE GASES

    • Branly Eugene, Philip A. Moore, Hong Li, Dana Miles, Steven Trabue, Robert Burns and Michael Buser
      Effect of Alum Additions to Poultry Litter on In-House Ammonia and Greenhouse Gas Concentrations and Emissions

      Alum [Al2(SO4)3 ·14H2O] addition to poultry litter has been shown to reduce ammonia (NH3) concentrations in poultry houses; however, its effects on greenhouse gas (GHG; N2O, CH4, and CO2) emissions is unknown. The objectives of this study were to determine the effects of alum additions on (i) in-house NH3 and GHG concentrations, (ii) NH3 and GHG emissions, and (iii) litter chemical properties. Two identical broiler houses located in northwest Arkansas were used for this study: one house was a control and the other was treated with alum between each flock of birds. Ventilation rates were coupled with in-house NH3 and GHG measurements to determine emission rates. (continued)

      Core Ideas:
      • Alum additions did affect NH3 concentrations in poultry houses.
      • Alum additions did affect NH3 emissions from poultry houses.
      • Alum additions did affect CO2 emissions from poultry houses.
      • Alum additions did not affect N2O and CH4 emissions from poultry houses.

      doi:10.2134/jeq2014.09.0404
      Published: August 21, 2015



    • Steven A. Cryer, Patrick L. Havens, David E. Hillger and Ian J. van Wesenbeeck
      An Improved Indirect Procedure for Estimating Pesticide Volatility from Field Trials

      Conventional indirect approaches for estimating pesticide volatility from agricultural fields require an air dispersion model and near-field, temporal air concentration measurements. The model pesticide flux profile is chosen such that field observations are recovered. Ross et al. (1996) first proposed a back-calculation method (BCM) using a single iteration of the Industrial Source Complex Short Term (ISCST) parameterized by a unit source flux. (continued)

      Core Ideas:
      • The classical back-calculation method is refined using optimization (BCMO).
      • The classical BCMO consistently improved flux estimates for all pesticides and scenarios investigated.
      • The classical BCMO can separate measured air concentrations to respective contributing sources.
      • The classical BCMO offers an improved alternative to the original methodology for all pesticides.

      doi:10.2134/jeq2015.03.0125
      Published: August 17, 2015



    • Hung V. Le, Eric C. Sivret, Gavin Parcsi and Richard M. Stuetz
      Impact of Storage Conditions on the Stability of Volatile Sulfur Compounds in Sampling Bags

      Odorous emissions from agricultural and waste management operations can cause annoyance to local populations. Volatile sulfur compounds (VSCs) are dominant odorants that are often lost during collection using sample bags. The degree of VSC losses depends on factors such as storage time, bag materials, temperature, sample relative humidity (RH), light exposure, and the presence of volatile organic compounds (VOCs). To assess the impact of those factors on the stability of 10 VSCs (hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, tert-butanethiol, ethyl methyl sulfide, 1-butanethiol, dimethyl disulfide, diethyl disulfide, and dimethyl trisulfide), laboratory-based experiments were conducted according to a factorial experimental design. (continued)

      Core Ideas:
      • Predictive models accommodate quick loss predictions for 10 VSCs.
      • Significant temperature and humidity interaction effects on VSC stability observed.
      • Significant light and humidity interaction effects on VSC stability observed.
      • Maximum storage of 18 h recommended in Tedlar to retain at least 75% of the VSCs.
      • Maximum storage of 12 h in Mylar and Nalophan to retain at least 74% of the VSCs.

      doi:10.2134/jeq2014.12.0532
      Published: August 17, 2015



  • BIOREMEDIATION AND BIODEGRADATION

    • Nicholson N. Jeke, Francis Zvomuya, Nazim Cicek, Lisette Ross and Pascal Badiou
      Biomass, Nutrient, and Trace Element Accumulation and Partitioning in Cattail ( Typha latifolia L.) during Wetland Phytoremediation of Municipal Biosolids

      Biomass and contaminant accumulation and partitioning in plants determine the harvest stage for optimum contaminant uptake during phytoremediation of municipal biosolids. This wetland microcosm bioassay characterized accumulation and partitioning of biomass, nutrients (N and P), and trace elements (Zn, Cu, Cr, and Cd) in cattail (Typha latifolia L.) in a growth room. Four cattail seedlings were transplanted into each 20-L plastic pail containing 3.9 kg (dry wt.) biosolids from an end-of-life municipal lagoon. A 10-cm-deep water column was maintained above the 12-cm-thick biosolids layer. (continued)

      Core Ideas:
      • Wetland system using cattail can remove contaminants from biosolids.
      • Wetland-based phytoremediation is more effective with two harvests than one harvest.
      • Phytoextraction is optimized if plants are harvested at maximum aboveground contaminant accumulation.

      doi:10.2134/jeq2015.02.0064
      Published: July 17, 2015



  • ENVIRONMENTAL ISSUES

    • J. Thad Scott and Brian E. Haggard
      Implementing Effects-Based Water Quality Criteria for Eutrophication in Beaver Lake, Arkansas: Linking Standard Development and Assessment Methodology

      To address water quality standards needed to prevent accelerated eutrophication, many states in the United States have developed effects-based standards related to nutrients. In many cases, this has resulted in specific standards for Secchi transparency (ST) and phytoplankton biomass measured as sestonic chlorophyll a (chl-a). The state of Arkansas recently adopted its first effects-based water quality criteria for Beaver Lake in northwestern Arkansas, which was a growing-season geometric mean chl-a <8 μg L−1 and an annual average ST >1.1 m. However, the adopted standard did not have a predefined assessment methodology that outlined the frequency and duration of potential exceedances. (continued)

      Core Ideas:
      • Linking water quality assessment methods to standard development has not been well established for numeric nutrient criteria.
      • Effects-based criteria are becoming more common but with little consideration of intra- and interannual variability and their influence on assessment.
      • Failure to consider assessment options in advance could result in unintended consequences during water quality assessment.

      doi:10.2134/jeq2015.01.0020
      Published: August 6, 2015



  • ENVIRONMENTAL MICROBIOLOGY

    • Emma C. Stea, Lisbeth Truelstrup Hansen, Rob C. Jamieson and Christopher K. Yost
      Fecal Contamination in the Surface Waters of a Rural- and an Urban-Source Watershed

      Surface waters are commonly used as source water for drinking water and irrigation. Knowledge of sources of fecal pollution in source watersheds benefits the design of effective source water protection plans. This study analyzed the relationships between enteric pathogens (Escherichia coli O157:H7, Salmonella spp., and Campylobacter spp. [C. (continued)

      Core Ideas:
      • Human marker (HF183) detection revealed human fecal contamination in both watersheds.
      • Ruminant markers (BacR and CowM2) only occurred in the rural watershed (6%).
      • The mtDNA markers were less sensitive due to lower initial fecal copy numbers.
      • E. coli ≥100 CFU 100 mL−1 or turbidity ≥1 NTU increased the odds of pathogen presence.
      • Storm events increased detection of pathogens and MST markers in the rural watershed.

      doi:10.2134/jeq2014.11.0459
      Published: August 28, 2015



    • Robert S. Dungan and April B. Leytem
      Detection of Purple Sulfur Bacteria in Purple and Non-purple Dairy Wastewaters

      The presence of purple bacteria in manure storage lagoons is often associated with reduced odors. In this study, our objectives were to determine the occurrence of purple sulfur bacteria (PSB) in seven dairy wastewater lagoons and to identify possible linkages between wastewater properties and purple blooms. Community DNA was extracted from composited wastewater samples, and a conservative 16S rRNA gene sequence within Chromatiaceae and pufM genes found in both purple sulfur and nonsulfur bacteria was amplified. Analysis of the genes indicated that all of the lagoons contained sequences that were 92 to 97% similar with Thiocapsa roseopersicina. (continued)

      Core Ideas:
      • PSB are often associated with reduced odors from livestock lagoons.
      • PSB were found in both purple and non-purple dairy wastewaters.
      • All dairy lagoons contained gene sequences similar to that of Thiocapsa roseopersicina.
      • It may be possible to stimulate the growth of PSB in non-purple ponds without inoculation.

      doi:10.2134/jeq2015.03.0128
      Published: July 31, 2015



  • ENVIRONMENTAL MODELS, MODULES, AND DATASETS

    • Lauren E. Padilla, Michael F. Winchell and Scott H. Jackson
      Evaluation of AGRO-2014 for Predicting Hydrophobic Organic Chemical Concentrations in Ponds

      Highly hydrophobic organic chemicals (HOCs), like pyrethroids, adsorb strongly to eroded soil and suspended sediment. Therefore, total suspended solids (TSS) concentration in the water column of receiving waters is important for determining the proportion of chemical in the sediment-sorbed vs. the dissolved (bioavailable) state. However, most current regulatory exposure models, such as the Exposure Analysis Modeling System (EXAMS) and Variable Volume Water Model (VVWM), do not include dynamic modeling of TSS. (continued)

      Core Ideas:
      • Novel comparison of three receiving-water models for predicting pesticide exposure.
      • Comparison of model predictions to mesocosm observed pyrethroid concentrations.
      • Evaluates importance of explicitly modeling sediment dynamics for hydrophobic organic chemicals.
      • Dynamic sediment processes significantly affected model results of high-KOC chemicals.
      • Introduction of the refined AGRO-2014 model for pesticide exposure modeling.

      doi:10.2134/jeq2015.03.0149
      Published: August 6, 2015



  • LANDSCAPE AND WATERSHED PROCESSES

    • Louise R.M. Barthod, Kui Liu, David A. Lobb, Philip N. Owens, Núria Martínez-Carreras, Alexander J. Koiter, Ellen L. Petticrew, Gregory K. McCullough, Cenwei Liu and Leticia Gaspar
      Selecting Color-based Tracers and Classifying Sediment Sources in the Assessment of Sediment Dynamics Using Sediment Source Fingerprinting

      The use of sediment color as a fingerprint property to determine sediment sources is an emerging technique that can provide a rapid and inexpensive means of investigating sediment sources. The present study aims to test the feasibility of color fingerprint properties to apportion sediment sources within the South Tobacco Creek Watershed (74 km2) in Manitoba, Canada. Suspended sediment from 2009 to 2011 at six monitoring stations and potential source samples along the main stem of the creek were collected. Reflectance spectra of sediments and source materials were quantified using a diffuse reflectance spectrometry, and 16 color coefficients were derived from several color space models. (continued)

      Core Ideas:
      • Defining sources and testing the behavior of tracers are critical for sediment source apportionment.
      • The predominant sources of river sediment varied at different reaches of the study creek.
      • Integrating color and conventional fingerprinting techniques likely improves source apportionment.
      • Color fingerprinting is a promising, cost-effective technique for sediment source ascription.

      doi:10.2134/jeq2015.01.0043
      Published: July 24, 2015



    • M. D. Sunohara, N. Gottschall, G. Wilkes, E. Craiovan, E. Topp, Z. Que, O. Seidou, S.K. Frey and D. R. Lapen
      Long-Term Observations of Nitrogen and Phosphorus Export in Paired-Agricultural Watersheds under Controlled and Conventional Tile Drainage

      Controlled tile drainage (CTD) regulates water and nutrient export from tile drainage systems. Observations of the effects of CTD imposed en masse at watershed scales are needed to determine the effect on downstream receptors. A paired-watershed approach was used to evaluate the effect of field-to-field CTD at the watershed scale on fluxes and flow-weighted mean concentrations (FWMCs) of N and P during multiple growing seasons. One watershed (467-ha catchment area) was under CTD management (treatment [CTD] watershed); the other (250-ha catchment area) had freely draining or uncontrolled tile drainage (UCTD) (reference [UCTD] watershed). (continued)

      Core Ideas:
      • Paired watershed study evaluates conventional and control drainage impacts at watershed scale.
      • Controlled tile drainage imposed en masse at watershed scales reduces stream, nitrate, ammonium, and dissolved reactive P fluxes during the growing season.
      • Total P fluxes in stream were shown to reduce and increase depending on location in watershed.

      doi:10.2134/jeq2015.01.0008
      Published: July 24, 2015



  • ORGANIC COMPOUNDS IN THE ENVIRONMENT

    • Guixiang Quan, Chuntao Yin, Tianming Chen and Jinlong Yan
      Degradation of Herbicide Mesotrione in Three Soils with Differing Physicochemical Properties from China

      The movement and fate of herbicides in soils under various environmental factors are important in evaluating their mobility and ecological impact. The effects of sterilization, solarization, and soil physicochemical properties on the degradation of herbicide mesotrione in three soils from China were evaluated using laboratory incubation method, and the degradation kinetics were also simulated using pseudo first-order reaction model. The calculated half-lives (t1/2) of mesotrione were found to be 3.78- to 5.24-fold increased in sterilized soils than nonsterilized soils, which indicated that the degradation of mesotrione was strongly affected by soil microbial activity. A certain role of promoting degradation effect of natural light was found, and the t1/2 values appeared to be only 7.90, 15.89, and 25.29 d−1 in the surface of paddy soil, sandy loess, and silt clay loam, respectively. (continued)

      Core Ideas:
      • Mesotrione degraded fastest in nonsterilized paddy soil with half-life ∼8.53 d.
      • Degradation of mesotrione was strongly affected by soil microbial activity.
      • Degradation rate constant was highly correlated with soil pH value and organic matter content.
      • Promoting degradation effect of solar light was found.

      doi:10.2134/jeq2014.12.0528
      Published: July 24, 2015



  • PLANT AND ENVIRONMENT INTERACTIONS

    • Aaron L. M. Daigh, Xiaobo Zhou, Matthew J. Helmers, Carl H. Pederson, Robert Horton, Meghann Jarchow and Matt Liebman
      Subsurface Drainage Nitrate and Total Reactive Phosphorus Losses in Bioenergy-Based Prairies and Corn Systems

      We compare subsurface-drainage NO3–N and total reactive phosphorus (TRP) concentrations and yields of select bioenergy cropping systems and their rotational phases. Cropping systems evaluated were grain-harvested corn–soybean rotations, grain- and stover-harvested continuous corn systems with and without a cover crop, and annually harvested reconstructed prairies with and without the addition of N fertilizer in an Iowa field. Drainage was monitored when soils were unfrozen during 2010 through 2013. The corn–soybean rotations without residue removal and continuous corn with residue removal produced similar mean annual flow-weighted NO3–N concentrations, ranging from 6 to 18.5 mg N L−1 during the 4-yr study. (continued)

      Core Ideas:
      • Bioenergy prairies limited NO3–N losses in subsurface drainage even when N fertilizer was applied.
      • Bioenergy continuous corn with cover crop can supply feedstocks while minimizing NO3–N losses.
      • Drainage TRP concentrations in bioenergy systems need evaluation in areas with high P losses.

      doi:10.2134/jeq2015.02.0080
      Published: July 31, 2015



  • SHORT COMMUNICATIONS

    • Tricia Coakley, Gail M. Brion and Alan E. Fryar
      Prevalence of and Relationship between Two Human-Associated DNA Biomarkers for Bacteroidales in an Urban Watershed

      Human-associated fecal biomarkers offer potent tools for the detection and control of human fecal pollution in watersheds. In some cases, the probability of false-negative findings may call for using a less specific biomarker that is present in higher quantities as long as it can be related to the more specific indicator. The objective of this study is to investigate the relationship between two previously published human-associated biomarkers for Bacteroidales bacteria in an urban watershed influenced by human fecal pollution and to determine if the less specific marker may be used to identify the locations of broken or leaking sewer lines. Samples were collected from 19 stream locations on 10 dates. (continued)

      Core Ideas:
      • The HuBac biomarker is linearly correlated to the more specific qHF183 biomarker.
      • Determine location, rather than identify an unknown source, with a more sensitive biomarker.
      • HuBac and qHF183 may be used in urban watershed studies.
      • A more sensitive marker is preferred when “less than” values are problematic in modeling.

      doi:10.2134/jeq2014.11.0494
      Published: July 31, 2015



  • SPECIAL SECTION: ANTIBIOTICS IN AGROECOSYSTEMS: STATE OF THE SCIENCE

    • Shanwei Xu, Srinivas Sura, Rahat Zaheer, George Wang, Alanna Smith, Shaun Cook, Andrew F. Olson, Allan J. Cessna, Francis J. Larney and Tim A. McAllister
      Dissipation of Antimicrobial Resistance Determinants in Composted and Stockpiled Beef Cattle Manure

      Windrow composting or stockpiling reduces the viability of pathogens and antimicrobial residues in manure. However, the impact of these manure management practices on the persistence of genes coding for antimicrobial resistance is less well known. In this study, manure from cattle administered 44 mg of chlortetracycline kg−1 feed (dry wt. basis) (CTC), 44 mg of CTC and 44 mg of sulfamethazine kg−1 feed (CTCSMZ), 11 mg of tylosin kg−1 feed (TYL), and no antimicrobials (control) were composted or stockpiled over 102 d. (continued)

      Core Ideas:
      • Dissipation of antimicrobial resistance genes was higher in composted than stockpiled manure.
      • Inclusion of antimicrobials in diet did not increase most anti-microbial resistance genes in manure.
      • Antimicrobials did alter copy numbers of bacteria in manure.
      • Measured genes declined from 0.5 to 3 log in stockpiled and composted manure.

      doi:10.2134/jeq2015.03.0146
      Published: August 28, 2015



  • SPECIAL SECTION: MICROBIAL TRANSPORT AND FATE IN THE SUBSURFACE

    • Feike J. Leij, Scott A. Bradford, Yusong Wang and Antonella Sciortino
      Langmuirian Blocking of Irreversible Colloid Retention: Analytical Solution, Moments, and Setback Distance

      Soil and aquifer materials have a finite capacity for colloid retention. Blocking of the limited number of available retention sites further decreases the rate of retention with time and enhances risks (e.g., pathogens or colloid-associated contaminants) or benefits (e.g., remediation by microorganisms or nanoparticles) of colloid migration. Our objective was to use a straightforward procedure, based on variable transformation and Laplace transform, to solve the problem of advective colloid transport with irreversible retention and Langmuirian blocking for a pulse-type condition. Formulas for the mean breakthrough time and retardation factor were obtained using zero- and first-order time moments of the breakthrough curves. (continued)

      Core Ideas:
      • Analytical solution for blocking of colloid retention.
      • Determination of zero and first moments.
      • Expressions for setback distance and arrival time.
      • Simulation of Escherichia coli D21g transport and retention.

      doi:10.2134/jeq2015.03.0147
      Published: August 21, 2015



    • Hehuan Liao, Leigh-Anne H. Krometis, Karen Kline and W. C. Hession
      Long-Term Impacts of Bacteria–Sediment Interactions in Watershed-Scale Microbial Fate and Transport Modeling

      Elevated levels of fecal indicator bacteria (FIB) remain the leading cause of surface water-quality impairments in the United States. Under the Clean Water Act, basin-specific total maximum daily load (TMDL) restoration plans are responsible for bringing identified water impairments in compliance with applicable standards. Watershed-scale model predictions of FIB concentrations that facilitate the development of TMDLs are associated with considerable uncertainty. An increasingly cited criticism of existing modeling practice is the common strategy that assumes bacteria behave similarly to “free-phase” contaminants, although many field evidence indicates a nontrivial number of cells preferentially associate with particulates. (continued)

      Core Ideas:
      • The HSPF model was modified to account for bacteria–sediment interactions.
      • Both water and sediment FIB concentrations were calibrated to observational data.
      • Improved model performance was achieved as compared to previous efforts.
      • Long-term impact of bacteria–sediment interactions in FIB predictions was negligible.
      • Watershed-specific characteristics likely affect the impact of sediment.

      doi:10.2134/jeq2015.03.0169
      Published: August 21, 2015



    • Raymond M. Flynn, German Mallèn, Marion Engel, Ashraf Ahmed and Pierre Rossi
      Characterizing Aquifer Heterogeneity Using Bacterial and Bacteriophage Tracers

      Gravel aquifers act as important potable water sources in central western Europe, yet they are subject to numerous contamination pressures. Compositional and textural heterogeneity makes protection zone delineation around groundwater supplies in these units challenging; artificial tracer testing aids characterization. This paper reappraises previous tracer test results in light of new geological and microbiological data. Comparative passive gradient testing, using a fluorescent solute (Uranine), virus (H40/1 bacteriophage), and comparably sized bacterial tracers Escherichia coli and Pseudomonas putida, was used to investigate a calcareous gravel aquifer’s ability to remove microbiological contaminants at a test site near Munich, Germany. (continued)

      Core Ideas:
      • Comparative tracer test in sand and gravel aquifer.
      • Use of similarly sized bacterial tracers and similarly charged bacterium and virus.
      • Microbiological tracer responses used to investigate subsurface heterogeneity.
      • Tracer test results reconciled with outcrop observations.

      doi:10.2134/jeq2015.02.0117
      Published: August 21, 2015



    • Nanxi Lu, Arash Massoudieh, Xiaomeng Liang, Dehong Hu, Tamir Kamai, Timothy R. Ginn, Julie L. Zilles and Thanh H. Nguyen
      Swimming Motility Reduces Azotobacter vinelandii Deposition to Silica Surfaces

      The transport and fate of bacteria in porous media is influenced by physicochemical and biological properties. This study investigated the effect of swimming motility on the attachment of Azotobacter vinelandii cells to silica surfaces through comprehensive analysis of cell deposition in model porous media. Distinct motilities were quantified for different strains using global and cluster-based statistical analyses of microscopic images taken under no-flow condition. The wild-type, flagellated strain DJ showed strong swimming as a result of the actively swimming subpopulation whose average speed was 25.6 μm/s; the impaired swimming of nifH strain DJ77 was attributed to the lower average speed of 17.4 μm/s in its actively swimming subpopulation; and both the nonflagellated JZ52 and chemically treated DJ cells were nonmotile. (continued)

      Core Ideas:
      • Statistical cluster analyses of cell trajectories separated actively swimming cells from nonswimming ones.
      • Motility was evaluated in multiple porous media model systems with increasing complexity.
      • Strong motility changed trajectories near the surface and reduced attachment.

      doi:10.2134/jeq2015.03.0141
      Published: August 21, 2015



    • Xunde Li, Edward R. Atwill, Elizabeth Antaki, Olin Applegate, Brian Bergamaschi, Ronald F. Bond, Jennifer Chase, Katherine M. Ransom, William Samuels, Naoko Watanabe and Thomas Harter
      Fecal Indicator and Pathogenic Bacteria and Their Antibiotic Resistance in Alluvial Groundwater of an Irrigated Agricultural Region with Dairies

      Surveys of microbiological groundwater quality were conducted in a region with intensive animal agriculture in California, USA. The survey included monitoring and domestic wells in eight concentrated animal feeding operations (CAFOs) and 200 small (domestic and community supply district) supply wells across the region. Campylobacter was not detected in groundwater, whereas Escherichia coli O157:H7 and Salmonella were each detected in 2 of 190 CAFO monitoring well samples. Nonpathogenic generic E. (continued)

      Core Ideas:
      • Systemic surveys of groundwater microbiological quality are performed at site and regional scales.
      • Confined animal systems are chronic sources of pathogens and high enteric microbial loads.
      • Pathogen loading to groundwater is effectively mitigated by alluvial aquifer system.
      • Some microbial indicators are too ubiquitous to be useful as indicators.
      • Antibiotic resistance from CAFOs and human sources affects the alluvial aquifer system.

      doi:10.2134/jeq2015.03.0139
      Published: August 21, 2015



    • Emmanuelle Arnaud, Anna Best, Beth L. Parker, Ramon Aravena and Kari Dunfield
      Transport of Escherichia coli through a Thick Vadose Zone

      Livestock manure applications on fields can be a source of contamination in water resources, including groundwater. Although fecal indicators like Escherichia coli have often been detected in tile drainage systems, few studies have monitored groundwater at depth after manure treatments, especially at sites with a deep, heterogeneous vadose zone. Our hypothesis was that microbial transport through a thick vadose zone would be limited or nonexistent due to attenuation processes, subsurface thickness, and heterogeneity. This study tested this hypothesis by monitoring E. (continued)

      Core Ideas:
      • E. coli was detected in groundwater 1 wk after manure application.
      • Underlying bedrock aquifer was contaminated despite a 12-m-thick vadose zone.
      • Results challenge our understanding of transport and fate in thick unsaturated zone.
      • Microbial transport to the deep water table suggests active preferential pathways.
      • Persistent low levels of E. coli suggest continued mobilization of bacteria.

      doi:10.2134/jeq2015.02.0067
      Published: August 17, 2015



    • Lee Burbery, Louise Weaver, Bronwyn Humphries and Jan Gregor
      Efficacy of Coral Sand for Removal of Escherichia coli and Bacteriophage under Saturated Flow Conditions

      Knowledge of how effectively microbes are transported through porous media is useful for water resource/wastewater management. Despite much research having been done to characterize microbial contaminant transport through various sedimentary materials, very little study has been made on coral sand, such as constitutes the primary substrate of many Pacific atolls. We conducted a set of laboratory column experiments as a preliminary examination of how effective coral sand is at attenuating model pathogens Escherichia coli J6-2 and MS2 bacteriophage (phage) under saturated flow conditions mildly representative of field conditions at the Bonriki freshwater lens, South Tarawa, Kiribati. The very poorly sorted gravelly sand coral substrate tested proved very effective at attenuating the bacterial tracer, and spatial removal rates of between 0.02 and 0.07 log10 cm−1 were determined for E. (continued)

      Core Ideas:
      • Effective removal rates of model pathogens were measured for saturated coral sand.
      • Lab-based transport experiments used E. coli J6-2 and MS2 bacteriophage.
      • Coral sand is effective at filtering E. coli, with removal rates of 0.02–0.07 log cm−1.
      • Coral sand did not provide significant natural attenuation of MS2 bacteriophage.

      doi:10.2134/jeq2015.01.0044
      Published: August 6, 2015



    • Margaret E. Stevenson, Regina Sommer, Gerhard Lindner, Andreas H. Farnleitner, Simon Toze, Alexander K.T. Kirschner, Alfred P. Blaschke and Jatinder P.S. Sidhu
      Attachment and Detachment Behavior of Human Adenovirus and Surrogates in Fine Granular Limestone Aquifer Material

      The transport of human adenovirus, nanoparticles, and PRD1 and MS2 bacteriophages was tested in fine granular limestone aquifer material taken from a borehole at a managed aquifer recharge site in Adelaide, South Australia. Comparison of transport and removal of virus surrogates with the pathogenic virus is necessary to understand the differences between the virus and surrogate. Because experiments using pathogenic viruses cannot be done in the field, laboratory tests using flow-through soil columns were used. Results show that PRD1 is the most appropriate surrogate for adenovirus in an aquifer dominated by calcite material but not under high ionic strength or high pH conditions. (continued)

      Core Ideas:
      • Adenovirus was compared to three surrogates: 100-nm particles and MS2 and PRD1 bacteriophages.
      • Column tests were performed in experiments using fine granular limestone aquifer material.
      • Column experiments under variable chemical conditions have not been done before using adenovirus.
      • PRD1 bacteriophage was the best surrogate to model the attachment of adenovirus but not detachment.
      • Implications of the work could influence interpretation of experiments using surrogates.

      doi:10.2134/jeq2015.01.0052
      Published: August 6, 2015



    • Ronald W. Harvey, David W. Metge, Denis R. LeBlanc, Jen Underwood, George R. Aiken, Kenna Butler, Timothy D. McCobb and Jay Jasperse
      Importance of the Colmation Layer in the Transport and Removal of Cyanobacteria, Viruses, and Dissolved Organic Carbon during Natural Lake-Bank Filtration

      This study focused on the importance of the colmation layer in the removal of cyanobacteria, viruses, and dissolved organic carbon (DOC) during natural bank filtration. Injection-and-recovery studies were performed at two shallow (0.5 m deep), sandy, near-shore sites at the southern end of Ashumet Pond, a waste-impacted, kettle pond on Cape Cod, MA, that is subject to periodic blooms of cyanobacteria and continuously recharges a sole-source drinking-water aquifer. The experiment involved assessing the transport behaviors of bromide (conservative tracer), Synechococcus sp. IU625 (cyanobacterium, 2.6 ± 0.2 µm), AS-1 (tailed cyanophage, 110 nm long), MS2 (coliphage, 26 nm diameter), and carboxylate-modified microspheres (1.7 µm diameter) introduced to the colmation layer using a bag-and-barrel (Lee-type) seepage meter. (continued)

      Core Ideas:
      • More than 98% of cyanobacteria, coliphages, and viruses being tracked were removed in the colmation layer.
      • Modified Lee-type seepage meters are useful for conducting colloid transport studies at the bottom of lakes.
      • 44% of the pond dissolved organic C transported into the aquifer was removed within the colmation layer.
      • Transport through the colmation layer resulted in a substantive change in dissolved organic C character.

      doi:10.2134/jeq2015.03.0151
      Published: July 31, 2015



    • Ivan Morales, José A. Amador and Thomas Boving
      Bacteria Transport in a Soil-Based Wastewater Treatment System under Simulated Operational and Climate Change Conditions

      Bacteria removal efficiencies in a conventional soil-based wastewater treatment system (OWTS) have been modeled to elucidate the fate and transport of E. coli bacteria under environmental and operational conditions that might be expected under changing climatic conditions. The HYDRUS 2D/3D software was used to model the impact of changing precipitation patterns, bacteria concentrations, hydraulic loading rates (HLRs), and higher subsurface temperatures at different depths and soil textures. Modeled effects of bacteria concentration shows that greater depth of treatment was required in coarser soils than in fine-textured ones to remove E. (continued)

      Core Ideas:
      • Retention of E. coli was modeled in a conventional onsite wastewater treatment.
      • The model was run under varied operational and climate changing conditions.
      • Lower hydraulic loading rate values removed more E. coli due to unsaturated conditions.
      • Precipitation and warmer soil temperatures affect E. coli removal in the soil.
      • Higher soil temperatures increased E. coli die-off rates and system performance.

      doi:10.2134/jeq2014.12.0547
      Published: July 24, 2015



    • Jack Schijven, Julia Derx, Ana Maria de Roda Husman, Alfred Paul Blaschke and Andreas H. Farnleitner
      QMRAcatch: Microbial Quality Simulation of Water Resources including Infection Risk Assessment

      Given the complex hydrologic dynamics of water catchments and conflicts between nature protection and public water supply, models may help to understand catchment dynamics and evaluate contamination scenarios and may support best environmental practices and water safety management. A catchment model can be an educative tool for investigating water quality and for communication between parties with different interests in the catchment. This article introduces an interactive computational tool, QMRAcatch, that was developed to simulate concentrations in water resources of Escherichia coli, a human-associated Bacteroidetes microbial source tracking (MST) marker, enterovirus, norovirus, Campylobacter, and Cryptosporidium as target microorganisms and viruses (TMVs). The model domain encompasses a main river with wastewater discharges and a floodplain with a floodplain river. (continued)


      doi:10.2134/jeq2015.01.0048
      Published: June 5, 2015



    • Ryan A. Blaustein, Yakov A. Pachepsky, Daniel R. Shelton and Robert L. Hill
      Release and Removal of Microorganisms from Land-Deposited Animal Waste and Animal Manures: A Review of Data and Models

      Microbial pathogens present a leading cause of impairment to rivers, bays, and estuaries in the United States, and agriculture is often viewed as the major contributor to such contamination. Microbial indicators and pathogens are released from land-applied animal manure during precipitation and irrigation events and are carried in overland and subsurface flow that can reach and contaminate surface waters and ground water used for human recreation and food production. Simulating the release and removal of manure-borne pathogens and indicator microorganisms is an essential component of microbial fate and transport modeling regarding food safety and water quality. Although microbial release controls the quantities of available pathogens and indicators that move toward human exposure, a literature review on this topic is lacking. (continued)


      doi:10.2134/jeq2015.02.0077
      Published: May 27, 2015



  • SPECIAL SECTION: SOIL IN THE CITY

    • Nele Delbecque and Ann Verdoodt
      Spatial Patterns of Heavy Metal Contamination by Urbanization

      Spatial analysis of heavy metals (HMs) is an important step toward developing predictive models of urban HM contamination. This study assessed the spatial distribution of the enrichment of eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the city of Ghent, Belgium. A database with soil HM concentrations measured at 2194 point observations was collected from the Public Waste Agency of Flanders. The degree of anthropogenic HM enrichment was quantified using an urban pollution index (PI). (continued)

      Core Ideas:
      • Urban pollution index maps reveal anthropogenic soil heavy metal (HM) enrichment.
      • In Ghent, soil HM enrichment is generally most pronounced for Ni, Cu, Pb, and Zn.
      • In Ghent, soil HM enrichment by As, Cd, Cr, and Hg is on average low.
      • Spatial patterns of HM enrichment reflect historical industrial contamination.
      • Time since development and land use relate to HM enrichment.

      doi:10.2134/jeq2014.11.0508
      Published: July 24, 2015



    • Sally Brown, Amber Corfman, Katrina Mendrey, Kate Kurtz and Fritz Grothkopp
      Stormwater Bioretention Systems: Testing the Phosphorus Saturation Index and Compost Feedstocks as Predictive Tools for System Performance

      A replicated column trial was conducted to evaluate the potential for the phosphorus saturation index (PSI) to predict P movement in bioretention soil mixtures (BSMs). The impact of compost feedstock on BSM performance was also evaluated. Three composts (biosolids/yard, yard/food waste, and manure/sawdust) were each brought to PSI values of 0.1, 0.5, and 1.0 through the addition of Fe-based water treatment residuals (WTRs) to lower the PSI and P salts to increase the PSI. A synthetic stormwater solution was used for 12 leaching events. (continued)

      Core Ideas:
      • Phosphorus saturation index predicts phosphorus movement in bioretention systems.
      • Compost feedstocks are not a good predictor of bioretention performance.
      • All bioretention mixtures had high copper removal.
      • Plant response varied by phosphorus saturation index and compost type.

      doi:10.2134/jeq2014.10.0414
      Published: July 17, 2015



    • Giada Brandani, Marco Napoli, Luciano Massetti, Martina Petralli and Simone Orlandini
      Urban Soil: Assessing Ground Cover Impact on Surface Temperature and Thermal Comfort

      The urban population growth, together with the contemporary deindustrialization of metropolitan areas, has resulted in a large amount of available land with new possible uses. It is well known that urban green areas provide several benefits in the surrounding environment, such as the improvement of thermal comfort conditions for the population during summer heat waves. The purpose of this study is to provide useful information on thermal regimes of urban soils to urban planners to be used during an urban transformation to mitigate surface temperatures and improve human thermal comfort. Field measurements of solar radiation, surface temperature (Ts), air temperature (Tair), relative humidity, and wind speed were collected on four types of urban soils and pavements in the city of Florence during summer 2014. (continued)


      doi:10.2134/jeq2014.12.0521
      Published: May 27, 2015



    • Sara C. Koropchak, W. Lee Daniels, Abbey Wick, G. Richard Whittecar and Nick Haus
      Beneficial Use of Dredge Materials for Soil Reconstruction and Development of Dredge Screening Protocols

      Upland placement of dredge sediments has the potential to provide beneficial reuse of suitable sediments for agricultural uses or urban soil reconstruction. However, the use of many dredge materials is limited by contaminants, and most established screening protocols focus on limiting major contaminants such as heavy metals and polycyclic aromatic hydrocarbons and generally ignore fundamental agronomic parameters. Since 2001, we have placed over 450,000 m3 of Potomac River fresh water dredge materials and 250,000 m3 of saline materials from various locations into monitored confined upland facilities in Charles City, VA, and documented their conversion to agricultural uses. Groundwater and soil quality monitoring has indicated no adverse effects from material placement and outstanding agricultural productivity for the freshwater materials. (continued)


      doi:10.2134/jeq2014.12.0529
      Published: May 15, 2015



    • Arjun K. Venkatesan, Abdul-Hakeem M. Hamdan, Vanessa M. Chavez, Jasmine D. Brown and Rolf U. Halden
      Mass Balance Model for Sustainable Phosphorus Recovery in a US Wastewater Treatment Plant

      In response to limited phosphorus (P) reserves worldwide, several countries have demonstrated the prospect of recovering significant amounts of P from wastewater treatment plants (WWTPs). This technique uses enhanced biological P removal (EBPR) to concentrate P in sludge followed by chemical precipitation of P as struvite, a usable phosphate mineral. The present study models the feasibility of this enhanced removal and recovery technique in a WWTP in Arizona with design parameters typical of infrastructure in the United States. A mass balance was performed for existing treatment processes and modifications proposed to estimate the quantity of P that could be recovered under current and future flow conditions. (continued)


      doi:10.2134/jeq2014.11.0504
      Published: March 27, 2015



  • SPECIAL SECTION: THE URBAN FOREST AND ECOSYSTEM SERVICES

    • S. J. Livesley, A. Ossola, C. G. Threlfall, A. K. Hahs and N. S. G. Williams
      Soil Carbon and Carbon/Nitrogen Ratio Change under Tree Canopy, Tall Grass, and Turf Grass Areas of Urban Green Space

      Soils in urban green spaces are an important carbon (C) store, but urban soils with a high carbon to nitrogen (C/N) ratio can also buffer N eutrophication from fertilizer use or atmospheric deposition. The influence of vegetation management practices on soil C cycling and C/N ratios in urban green spaces is largely unknown. In 2013, we collected replicate (n = 3) soil samples from tree canopy, tall grass, and short turf grass areas (n = 3) at four random plot locations (n = 4) established in 13 golf courses (n = 13). At each sample point, soil was separated into 0- to 0.1-, 0.1- to 0.2-, and 0.2- to 0.3-m depths (total n = 1404). (continued)

      Core Ideas:
      • We sampled soil under tree canopy, tall grass, and short grass in 13 urban greenspaces.
      • Tree canopy soil had significantly greater soil C density and C/N ratios.
      • Soil C/N ratios increased significantly with increasing green space age.
      • Soil C and C/N were best modeled by tree basal area and understory vegetation.
      • Tree canopy areas can be managed to buffer nitrogen eutrophication.

      doi:10.2134/jeq2015.03.0121
      Published: August 21, 2015



    • Qingfu Xiao and E. Gregory McPherson
      Surface Water Storage Capacity of Twenty Tree Species in Davis, California

      Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage capacity is known to vary widely among tree species, but it is little studied. This research measured surface storage capacities of 20 urban tree species in a rainfall simulator. (continued)

      Core Ideas:
      • Quantitative analysis of surface water storage capacities for 20 urban tree species.
      • Surface water storage capacities varied threefold among tree species.
      • Conifers had the highest storage capacities and simulated interception rates.

      doi:10.2134/jeq2015.02.0092
      Published: August 17, 2015



    • E. C. Denman, P. B. May and G. M. Moore
      The Potential Role of Urban Forests in Removing Nutrients from Stormwater

      Biofiltration systems can be used to improve the quality of stormwater by treating runoff using plants grown in a moderately permeable soil. Most biofilters use herbaceous species, but in highly urbanized locations, such as streets, trees may be a more suitable vegetation. Biofilters that use urban woody vegetation are less studied. This experiment investigated the use of four street tree species [Eucalyptus polyanthemos Schauer, Lophostemon confertus (R. (continued)

      Core Ideas:
      • Street trees reduced N and P concentrations compared with unplanted profiles.
      • Street trees receiving stormwater generally grew larger.
      • Differences between tree species in nutrient removal performance were not large.
      • It is relatively easy to reduce P in leachate, while nitrogen is more difficult.
      • Organic matter addition to biofiltration soils is not recommended.

      doi:10.2134/jeq2015.01.0047
      Published: July 27, 2015



    • J. Deak Sjöman, A. Hirons and H. Sjöman
      Branch Area Index of Solitary Trees: Understanding Its Significance in Regulating Ecosystem Services

      The chief aim of this study was to investigate how different species of solitary trees in temperate urban areas vary in their branch structure during winter by assessing branch area indices (BAIs). The BAI data showed significant differences (P < 0.0001) between species and genotypes. The lowest mean BAI in the dataset was for Gingko biloba L., which had a BAI of 0.27. Pinus strobus L. (continued)

      Core Ideas:
      • Branch density and architectural make up of solitaire trees differ in winter.
      • Branch area indices vary significantly between species and genotypes of trees.
      • Different branch area indices will influence mean radiant temperature and wind speed in a complex urban setting.
      • The results are discussed with regards to the design of urban green space.

      doi:10.2134/jeq2015.02.0069
      Published: July 24, 2015



    • Paloma Cariñanos, Cristiano Adinolfi, Consuelo Díaz de la Guardia, Concepción De Linares and Manuel Casares-Porcel
      Characterization of Allergen Emission Sources in Urban Areas

      Pollen released by urban flora—a major contributor to airborne allergen content during the pollen season—has a considerable adverse impact on human health. Using aerobiological techniques to sample and characterize airborne biological particulate matter (BPM), we can identify the main species contributing to the pollen spectrum and chart variations in counts and overall pollen dynamics throughout the year. However, given the exponential increase in the number of pollen allergy sufferers in built-up areas, new strategies are required to improve the biological quality of urban air. This paper reports on a novel characterization of the potential allergenicity of the tree species most commonly used as ornamentals in Mediterranean cities. (continued)

      Core Ideas:
      • Pollen emissions by urban flora are the chief source of airborne allergens.
      • A novel characterization of the potential allergenicity of urban trees is presented.
      • Wind-pollinated species are associated with higher allergenicity values.
      • Assigning an allergenic value to each tree species will help to improve air quality.

      doi:10.2134/jeq2015.02.0075
      Published: July 17, 2015



    • Bryant C. Scharenbroch, Justin Morgenroth and Brian Maule
      Tree Species Suitability to Bioswales and Impact on the Urban Water Budget

      Water movement between soil and the atmosphere is restricted by hardscapes in the urban environment. Some green infrastructure is intended to increase infiltration and storage of water, thus decreasing runoff and discharge of urban stormwater. Bioswales are a critical component of a water-sensitive urban design (or a low-impact urban design), and incorporation of trees into these green infrastructural components is believed to be a novel way to return stored water to the atmosphere via transpiration. This research was conducted in The Morton Arboretum’s main parking lot, which is one of the first and largest green infrastructure installations in the midwestern United States. (continued)


      doi:10.2134/jeq2015.01.0060
      Published: June 12, 2015



    • Ruzana Sanusia, Denise Johnstone, Peter May and Stephen J. Livesley
      Street Orientation and Side of the Street Greatly Influence the Microclimatic Benefits Street Trees Can Provide in Summer

      Maintaining human thermal comfort (HTC) is essential for pedestrians because people outside can be more susceptible to heat stress and heat stroke. Modification of street microclimates using tree canopy cover can provide important benefits to pedestrians, but how beneficial and under what circumstances is not clear. On sunny summer days, microclimatic measures were made in residential streets with low and high percentages of tree canopy cover in Melbourne, Australia. Streets with east-west (E-W) and streets with north-south (N-S) orientation were repeatedly measured for air temperature, relative humidity, wind speed, solar radiation, and mean radiant temperature on both sides of the street between early morning and midafternoon. (continued)


      doi:10.2134/jeq2015.01.0039
      Published: June 5, 2015



  • SURFACE WATER QUALITY

    • Sarah A. Doydora, Dorcas Franklin, Peizhe Sun, Miguel Cabrera, Aaron Thompson, Kimberly Love-Myers, John Rema, Vaughn Calvert, Spyros G. Pavlostathis and Ching-Hua Huang
      Alum and Rainfall Effects on Ionophores in Runoff from Surface-Applied Broiler Litter

      Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an acidic material such as aluminum sulfate (alum) would reduce ionophore losses to runoff (i.e., monensin and salinomycin concentrations, loads, or amounts lost). We quantified ionophore loss to runoff in response to (i) addition of alum to broiler litter and (ii) length of time between litter application and the first simulated rainfall event. (continued)

      Core Ideas:
      • Two methods to reduce anticoccidials in runoff from grasslands receiving broiler litter.
      • Ionophore losses in surface runoff can be reduced by adding alum to broiler litter.
      • Ionophores in runoff decreased when rainfall occurs 2 to 4 weeks after broiler litter application.

      doi:10.2134/jeq2015.02.0099
      Published: August 28, 2015



    • J. J. Jiménez, N. Darwiche-Criado, R. Sorando, F. A. Comín and J. M. Sánchez-Pérez
      A Methodological Approach for Spatiotemporally Analyzing Water-Polluting Effluents in Agricultural Landscapes Using Partial Triadic Analysis

      Multivariate techniques for two-dimensional data matrices are normally used in water quality studies. However, if the temporal dimension is included in the analysis, other statistical techniques are recommended. In this study, partial triadic analysis was used to investigate the spatial and temporal variability in water quality variables sampled in a northeastern Spain river basin. The results highlight the spatiality of the physical and chemical properties of water at different sites along a river over 1 yr. (continued)

      Core Ideas:
      • The spatiality of the physicochemical properties of water along a river is demonstrated.
      • PTA can efficiently summarize site-specific water chemistry patterns.
      • Significant positive and negative autocorrelation at several distance lags was shown.
      • PTA is useful for evaluating and monitoring water quality.

      doi:10.2134/jeq2014.09.0377
      Published: August 21, 2015



    • Natasha Bell, Richard A. C. Cooke, Todd Olsen, Mark B. David and Robert Hudson
      Characterizing the Performance of Denitrifying Bioreactors during Simulated Subsurface Drainage Events

      The need to mitigate nitrate export from corn and soybean fields with subsurface (tile) drainage systems, a major environmental issue in the midwestern United States, has made the efficacy of field-edge, subsurface bioreactors an active subject of research. This study of three such bioreactors located on the University of Illinois South Farms during their first 6 mo of operation (July–Dec. 2012) focused on the interactions of seasonal temperature changes and hydraulic retention times (HRTs), which were subject to experimental manipulation. Changes in nitrate, phosphate, oxygen, and dissolved organic carbon were monitored in influent and effluent to assess the benefits and the potential harmful effects of bioreactors for nearby aquatic ecosystems. (continued)

      Core Ideas:
      • Bioreactors successfully reduced nitrate loads from drainage tiles.
      • Nitrate removal rate was independent of hydraulic residence time.
      • Initially high DRP and DO were reduced after a month of operation.
      • Temperature and residence time explained 85% of the variance in N load reduction.
      • Temperature and residence time explained 66% of the variance in N removal rate.

      doi:10.2134/jeq2014.04.0162
      Published: July 24, 2015



  • VADOSE ZONE PROCESSES AND CHEMICAL TRANSPORT

    • Marco Napoli, Stefano Cecchi, Camillo A. Zanchi and Simone Orlandini
      Leaching of Glyphosate and Aminomethylphosphonic Acid through Silty Clay Soil Columns under Outdoor Conditions

      Glyphosate [N-(phosphono-methyl)-glycine] is the main herbicide used in the Chianti vineyards. Considering the pollution risk of the water table and that the vineyard tile drain may deliver this pollutant into nearby streams, the objective of the present study was to estimate the leaching losses of glyphosate under natural rainfall conditions in a silty clay soil in the Chianti area. The leaching of glyphosate and its metabolite (aminomethylphosphonic acid [AMPA]) through soils was studied in 1-m-deep soil columns under outdoor conditions over a 3-yr period. Glyphosate was detected in the leachates for up to 26 d after treatments at concentrations ranging between 0.5 and 13.5 μg L−1. (continued)

      Core Ideas:
      • Leaching of glyphosate and AMPA was assessed in 1-m soil columns.
      • Glyphosate and AMPA may be transported in leachates through 100 cm of silty clay soil profile.
      • About 0.82%, on average, of the total glyphosate applied was recovered in soil and leachate.

      doi:10.2134/jeq2015.02.0104
      Published: July 31, 2015



  • WASTE MANAGEMENT

    • J. G. Murnane, R. B. Brennan, M. G. Healy and O. Fenton
      Use of Zeolite with Alum and Polyaluminum Chloride Amendments to Mitigate Runoff Losses of Phosphorus, Nitrogen, and Suspended Solids from Agricultural Wastes Applied to Grassed Soils

      Diffuse pollutant losses containing phosphorus (P), nitrogen (N), and suspended solids (SS) can occur when agricultural wastes are applied to soil. This study aimed to mitigate P, N, and SS losses in runoff from grassed soils, onto which three types of agricultural wastes (dairy slurry, pig slurry, and dairy-soiled water [DSW]), were applied by combining amendments of either zeolite and polyaluminum chloride (PAC) with dairy and pig slurries or zeolite and alum with DSW. Four treatments were investigated in rainfall simulation studies: (i) control soil, (ii) agricultural wastes, (iii) dairy and pig slurries amended with PAC and DSW amended with alum, and (iv) dairy and pig slurries amended with zeolite and PAC and DSW amended with zeolite and alum. Our data showed that combined amendments of zeolite and PAC applied to dairy and pig slurries reduced total P (TP) in runoff by 87 and 81%, respectively, compared with unamended slurries. (continued)

      Core Ideas:
      • Surface runoff studies have mainly focused on mitigation of one contaminant.
      • This paper optimizes mitigation of two contaminants by optimizing amendments.
      • Zeolite and chemical mixtures increased N and P removal from agricultural waste.
      • More N and P were removed from zeolite and chemical mixtures than chemicals only.
      • Zeolite and chemical mixtures improved suspended solids removal from dairy soiled water runoff.

      doi:10.2134/jeq2014.07.0319
      Published: July 24, 2015



  • WETLANDS AND AQUATIC PROCESSES

    • Julia G. Lazar, Kelly Addy, Arthur J. Gold, Peter M. Groffman, Richard A. McKinney and Dorothy Q. Kellogg
      Beaver Ponds: Resurgent Nitrogen Sinks for Rural Watersheds in the Northeastern United States

      Beaver-created ponds and dams, on the rise in the northeastern United States, reshape headwater stream networks from extensive, free-flowing reaches to complexes of ponds, wetlands, and connecting streams. We examined seasonal and annual rates of nitrate transformations in three beaver ponds in Rhode Island under enriched nitrate-nitrogen (N) conditions through the use of 15N mass balance techniques on soil core mesocosm incubations. We recovered approximately 93% of the nitrate N from our mesocosm incubations. Of the added nitrate N, 22 to 39% was transformed during the course of the incubation. (continued)

      Core Ideas:
      • In rural watersheds of southern New England with high N loading, denitrification from beaver ponds may remove 5–45% of watershed nitrate-N loading.
      • Beaver ponds represent a relatively new, substantial sink for watershed N if current beaver populations persist.
      • Denitrification had the highest rates of nitrate transformation in our beaver pond study, with N2 as the dominant product.

      doi:10.2134/jeq2014.12.0540
      Published: July 24, 2015



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