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| Registros recuperados: 40 | |
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| Alves, B.S.Q.; Dungan, R.S.; Carnin, R.L.P; Galvez, R.; de Carvalho Pinto, C.R.S.. |
| While most waste molding foundry sands (WFSs) are not hazardous in nature, regulatory agencies are often reluctant to permit their beneficial use in agricultural and geotechnical applications due to concerns over metal leaching. The objective of this study was to quantify total and Toxicity Characteristic Leaching Procedure (TCLP) metals in 16 waste sands from Brazilian ferrous foundries and assess their potential to leach metals to groundwater using a probabilistic model developed by the U.S. EPA. Total and TCLP metal concentrations in the non-hazardous sands fell within ranges as reported in the literature, although some of the leachate concentrations were found to exceed drinking water and groundwater maximum contaminant levels MCLs. Leachate values... |
| Tipo: Article |
Palavras-chave: Foundry sand. |
| Ano: 2014 |
URL: http://eprints.nwisrl.ars.usda.gov/1537/1/1494.pdf |
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| Bougouin, Adeline; Leytem, A.B.; Dijkstra, Jan; Dungan, R.S.; Kebreab, Ermias. |
| Nitrogen (N) excreted in urine by dairy cows can be potentially transformed to ammonia (NH3) and emitted to the atmosphere. Dairy production contributes to NH3 emission, which can create human respiratory problems and odor issues, reduces manure quality, and is an indirect source of nitrous oxide (N2O). The objective of this study was to (i) investigate environmental factors and measurement method that influence NH3 from dairy housing, and (ii) identify key explanatory variables in the prediction of NH3 emissions from dairy barns using a meta-analytical approach. Data from 25 studies were used for the preliminary analysis and data from 10 studies reporting 87 treatment means were used for the meta-analysis. Season, flooring type, manure handling and... |
| Tipo: Article |
Palavras-chave: Air Emissions; Animal Production; Animal health; Manure. |
| Ano: 2016 |
URL: http://eprints.nwisrl.ars.usda.gov/1624/1/1581.pdf |
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| Carnin, R.L.P; Folgueras, M.V.; Luvizao, R.R.; Correia, S.L.; da Cunha, C.J.; Dungan, R.S.. |
| A fresh green sand, spent green sand, and a weathered spent green sand from a landfill were analyzed using diffractometry, electron microscopy, granulometry, spectrometry, and thermogravimetry. Our objective was to understand how the physicochemical properties of the green sands change from their original form after being subjected to the casting process, then after weathering at the landfill. A quantitative phase composition model was also postulated for each material based on thermogravimetric results and it was found to be the most reliable and informative quantitative data for this type of residue. The weathered sample, that remained in a landfill for two years, was found to be composed of almost pure sand. Because of the weathering process, it may... |
| Tipo: Article |
Palavras-chave: Soil. |
| Ano: 2012 |
URL: http://eprints.nwisrl.ars.usda.gov/1458/1/1423.pdf |
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| Dayton, E.A.; Whitacre, S.D.; Dungan, R.S.; Basta, N.T.. |
| Abstract As of 2007, of the 2,000 United States foundries, 93% produce ferrous or aluminum castings, generating 9.4 million tons of non-hazardous spent foundry sand (SFS) annually. Only 28% of the SFS is beneficially used. The U.S. EPA Resource Conservation Challenge identifies SFS as a priority material for beneficial use, with soil blending as a potential reuse option. The objectives of this work were to measure: (1) select chemical and physical properties important to soil quality and function and (2) total and soluble elemental content of 39 SFSs, in order to evaluate SFS suitability as a component in manufactured soils. Total elemental concentration of the SFS was lower than natural background soil levels for most elements analyzed, suggesting limited... |
| Tipo: Article |
Palavras-chave: Soil. |
| Ano: 2010 |
URL: http://eprints.nwisrl.ars.usda.gov/1359/1/1336.pdf |
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| Dungan, R.S.. |
| In the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aerosolized during center pivot irrigation of diluted dairy wastewaters. The dispersion of pathogens (Campylobacter jejuni, Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, and Salmonella spp.) was modeled using the atmospheric dispersion model, AERMOD. Pathogen concentrations at downwind receptors were used to calculate infectious risks during one-time (1, 8, and 24 h) and multi-day (7 d at 1 h/d) exposure events using a Beta-Poisson... |
| Tipo: Article |
Palavras-chave: Microbial Transport; Center pivot. |
| Ano: 2014 |
URL: http://eprints.nwisrl.ars.usda.gov/1538/1/1495.pdf |
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| Dungan, R.S.. |
| Animal manures are known to harbor a variety of zoonotic pathogens, which are suspected of being transported off-site as aerosols from confined feeding operations. In this study, aerosols were collected using a high-volume sampler downwind from a 10,000 cow open-freestall dairy and nearby fields being sprinkler irrigated with wastewater. DNA extracts were prepared from the aerosol samples, then a region of the16S ribosomal RNA gene was sequenced for bacterial identification and phylogenetic classification. At the dairy and irrigation sites, Proteobacteria was the most abundant phylum, representing 78% and 69% of all sequences, respectively, while Actinobacteria, Bacteroidetes and Firmicutes represented only 10% or less of the sequences. Of the 191... |
| Tipo: Article |
Palavras-chave: Sprinkler irrigation; Manure. |
| Ano: 2012 |
URL: http://eprints.nwisrl.ars.usda.gov/1445/1/1410.pdf |
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| Dungan, R.S.. |
| Airborne microorganisms and microbial byproducts from intensive livestock and manure management systems are a potential health risk to workers and individuals in nearby communities. This report presents information on zoonotic pathogens in animal wastes and the generation, fate, and transport of bioaerosols associated with animal feeding operations and land applied manures. Though many bioaerosol studies have been conducted at animal production facilities, few have investigated the transport of bioaerosols during the land application of animal manures. As communities in rural areas converge with land application sites, concerns over bioaerosol exposure will certainly increase. While most studies at animal operations and wastewater spray irrigation sites... |
| Tipo: Article |
Palavras-chave: Manure Management; Manure. |
| Ano: 2010 |
URL: http://eprints.nwisrl.ars.usda.gov/1405/1/1375.pdf |
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| Dungan, R.S.. |
| Airborne endotoxin in occupational environments are a potential respiratory hazard to individuals. In this study, total and inhalable airborne endotoxin samples were collected via filtration from inside animal housing units and downwind from agricultural production sites and a wastewater treatment plant. Filter extracts were then diluted to examine the effect of interfering substances on the kinetic Limulus amebocyte lysate (LAL) assay. In most cases, the overall endotoxin concentration was shown to decrease with increasing dilution up to 1,000-fold, suggesting the presence of enhancing substances in the filter extracts. This dilution dependent effect was most prominent in the inhalable endotoxin samples, while total endotoxin samples displayed little... |
| Tipo: Article |
Palavras-chave: Air Emissions; Endotoxins. |
| Ano: 2011 |
URL: http://eprints.nwisrl.ars.usda.gov/1410/1/1380.pdf |
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| Dungan, R.S.; Bjorneberg, D.L.; Leytem, A.B.. |
| In this study we conducted simulated spray irrigation events of dairy wastewater to assess the impact of pressure and sprinkler type upon post-sprinkler culturable microorganism concentrations. Dairy wastewater was sampled before and after it was pumped through sprinklers typically used on center pivot irrigation systems. Three different sprinklers types were used at three different operating pressures to give a range of water drop sizes. The microorganisms quantified in this study were total coliforms, Escherichia coli, Clostridium perfringens, heterotrophic bacteria, and coliphage. In most cases the pre- and post-sprinkler concentrations were determined to be statistically similar, suggesting that culturable viability was not affected when wastewater... |
| Tipo: Article |
Palavras-chave: Sprinkler irrigation; Manure. |
| Ano: 2011 |
URL: http://eprints.nwisrl.ars.usda.gov/1444/1/1409.pdf |
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| Dungan, R.S.; Kim, J.; Weon, H.; Leytem, A.B.. |
| The purpose of this research was to characterize the structure and composition of bacterial communities in sandy loam and silty clay soils amended with 30% spent sand from iron, aluminum, and steel foundries. All spent foundry sand (SFS) blends were grown with or without perennial ryegrass and samples were collected at 4 weeks and 6 months. Regions of the 16S rRNA gene were amplified using PCR and subsequently analyzed by DGGE and sequenced for bacterial identification and phylogenetic classification. Cluster analyses of PCR-DGGE banding patterns revealed that SFS blends from week 4 and month 6 produced unique clusters, with most ryegrass treatments clustering away from those without ryegrass. The diversity of the bacterial community revealed that it... |
| Tipo: Article |
Palavras-chave: Soil; Soil quality. |
| Ano: 2009 |
URL: http://eprints.nwisrl.ars.usda.gov/1339/1/1316.pdf |
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| Dungan, R.S.; Kim, Jong-Shik; Makama, Mfundi; Petito, Janine; Park, Nyun-Ho; Cohan, F.M.. |
| The objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain-specific primers, a region of the 16S rRNA gene was amplified using PCR, and the product was subsequently used to create a clone library. A total of 243 bacterial clones, 99 archaeal clones, and 209 bacterial isolates were examined. The 243 clones from Bacteria were affiliated with the following groups: the Bacilli (59 clones) and Clostridia (1) of the Firmicutes, Bacteroidetes (90), Proteobacteria (27), Cyanobacteria (18), Gemmatimonadetes (41), candidate division OP1 (5), Actinobacteria (1), and the Deinococcus-Thermus division (1). Within the class Bacilli, 46 of 59... |
| Tipo: Article |
Palavras-chave: Soil. |
| Ano: 2012 |
URL: http://eprints.nwisrl.ars.usda.gov/1453/1/1418.pdf |
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| Dungan, R.S.; Klein, Marcus; Leytem, A.B.. |
| Zoonotic pathogens in land-applied dairy wastewaters are a potential health risk. The abundance and occurrence of 10 pathogens and 3 fecal indicators was determined by quantitative real-time PCR (qPCR) in 30 dairy wastewaters from southern Idaho. Samples tested positive for Campylobacter jejuni, stx1- and eaeA-positive Escherichia coli, Listeria monocytogenes, Mycobacterium avium, and Salmonella enterica, with mean recoveries ranging from 1,000 to 10,000 genome copies per mL of wastewater. The most dominant organisms were C. jejuni and M. avium, being detected in up to 21 and 29 of 30 wastewater ponds, respectively. The qPCR detection limits for the putative pathogens in the wastewaters ranged from 16 cells mL for M. avium to 1,689 oocysts mL for... |
| Tipo: Article |
Palavras-chave: Chemistry; Manure. |
| Ano: 2012 |
URL: http://eprints.nwisrl.ars.usda.gov/1473/1/1438.pdf |
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| Dungan, R.S.; Leytem, A.B.. |
| The generation of airborne microorganisms from concentrated animal-feeding operations (CAFOs) is a concern from a human and animal health perspective. To better understand the airborne microorganisms found in these environments, a number of collection and analytical techniques have been utilized and will be discussed in this review. The most commonly used bioaerosol collection method is the liquid impingement format, which is suitable with a number of culture-based and non-culture molecularbased approaches, such as polymerase chain reaction. However, the vast majority of airborne microorganism studies conducted at CAFOs utilize culture-based analyses. Because of the limitations often associated with culturebased analyses, we focused our... |
| Tipo: Article |
Palavras-chave: Manure; Animal. |
| Ano: 2009 |
URL: http://eprints.nwisrl.ars.usda.gov/1337/1/1314.pdf |
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| Dungan, R.S.; Leytem, A.B.. |
| Collection fluids used in liquid-based bioaerosol samplers can influence the viability of microorganisms. In this study we determined the recovery efficiency of vegetative E. coli O157:H7 cells that were spiked into low viscosity evaporating collection fluids during operation of a BioSampler™ for up to 90 min at room temperature. The collection fluids tested were distilled (DI) water, phosphate-buffered saline (PBS) and osmoprotectants consisting of peptone and/or antifoam or betaine at 0.1% (w/w) in DI water. Using DI water, there was a rapid decline in the recovery of culturable E. coli, with only 11, 3, and 0% being recovered after 30, 60, and 90 min, respectively. Recoveries were substantially greater with use of PBS (53, 25, and 16%, respectively) but... |
| Tipo: Article |
Palavras-chave: Air Emissions; Water quality. |
| Ano: 2016 |
URL: http://eprints.nwisrl.ars.usda.gov/1613/1/1570.pdf |
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| Dungan, R.S.; Leytem, A.B.. |
| Endotoxins are derived from gram-negative bacteria and are a potential respiratory health risk for animals and humans. To determine the potential for endotoxin transport from a large open-lot dairy, total airborne endotoxin concentrations were determined at an upwind location (background) and five downwind locations on three separate days. The downwind locations were situated at of the edge of the lot, 200 and 1390 m downwind from the lot, and downwind from a manure composting area and wastewater holding pond. When the wind was predominantly from the west, the average endotoxin concentration at the upwind location was 24 endotoxin units (EU) m?3, whereas at the edge of the lot on the downwind side it was 259 EU m?3. At 200 and 1390 m downwind... |
| Tipo: Article |
Palavras-chave: Manure. |
| Ano: 2009 |
URL: http://eprints.nwisrl.ars.usda.gov/1330/1/1307.pdf |
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| Dungan, R.S.; Leytem, A.B.. |
| Purple sulfur bacteria (PSB) in livestock wastewaters use reduced sulfur compounds and simple volatile organics as growth factors. As a result, the presence of PSB in manure storage ponds or lagoons is often associated with reduced odors. In this study, our objectives were to use molecular- and culture-based techniques to evaluate the occurrence of PSB in eight dairy wastewater ponds and identify physiochemical properties that might cause blooms to occur. Community DNA was extracted from composited wastewater samples, then the PufM gene and a conservative sequence for Chromatiaceae were amplified. Analysis of the 16S rRNA genes from denaturing gradient gel electrophoresis (DGGE) bands indicated that all of the dairy wastewater ponds contained sequences... |
| Tipo: Article |
Palavras-chave: Air Emissions. |
| Ano: 2015 |
URL: http://eprints.nwisrl.ars.usda.gov/1604/1/1562.pdf |
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| Registros recuperados: 40 | |
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