Abstract:
:Laboratory microcosm experiments were used to assess the effects of environmental parameters on the persistence of the Bacteroides 16S rRNA genes derived from equine fecal samples in stream water to investigate the utility of Bacteroides spp. as fecal indicator organisms. Quantitative real-time polymerase chain reaction (qPCR) was used to measure gene concentrations over time with treatments designed to compare filtered vs. unfiltered stream water, fecal aggregate size, initial fecal concentrations, and water temperatures. Comparison of Bacteroides16S rRNA genes/mL in microcosms constructed with unfiltered stream water and filtered stream water indicated that stream water filtration to remove indigenous microorganisms followed by temperature had the largest effects on gene persistence. First-order exponential decay functions were fitted to the data from each microcosm constructed using unfiltered stream water, and the decay constants (k) ranged from 0.0071 h(-1) in the microcosms incubated at 5 degrees C to 0.0336 h(-1) in a set of microcosms incubated at 25 degrees C. Analysis of k calculated from the 10 experimental treatments indicated that k is more highly correlated to temperature than initial Bacteroides 16S rRNA gene starting concentrations. The equation resulting from graphing k (as the dependent variable) vs. temperature (as the independent variable) best fit a peak, Gaussian, 3 parameter function with a maximum decay at 30 degrees C, a r(2) of 0.83 and all parameters were significant (P < 0.0015). Thus this data suggest that factors that reduce biological activity, such as physical removal of stream microorganisms by filtration and low temperature, result in slower Bacteroides 16S rRNA gene decay.
journal_name
J Environ Qualjournal_title
Journal of environmental qualityauthors
Bell A,Layton AC,McKay L,Williams D,Gentry R,Sayler GSdoi
10.2134/jeq2008.0258subject
Has Abstractpub_date
2009-04-27 00:00:00pages
1224-32issue
3eissn
0047-2425issn
1537-2537pii
38/3/1224journal_volume
38pub_type
杂志文章abstract::Water treatment residuals (WTRs) are a by-product of municipal drinking water treatment plants and can have the capacity to adsorb tremendous amounts of P. Understanding the WTR phosphorus adsorption process is important for discerning the mechanism and tenacity of P retention. We studied P adsorbing mechanism(s) of a...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2003.1857
更新日期:2003-09-01 00:00:00
abstract::Interest in the use of biochar from pyrolysis of biomass to sequester C and improve soil productivity has increased; however, variability in physical and chemical characteristics raises concerns about effects on soil processes. Of particular concern is the effect of biochar on soil N dynamics. The effect of biochar on...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2011.0133
更新日期:2012-07-01 00:00:00
abstract::There are growing concerns regarding the fate of nutrients, especially phosphorus (P), from land application of animal waste. One approach being studied to reduce runoff losses of P is to treat manure or the soil receiving manure with chemical amendments such as gypsum. This study used rainfall simulations to examine ...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2012.0422
更新日期:2014-01-01 00:00:00
abstract::Terbuthylazine (TA) is a herbicide that has been introduced for weed control in corn cultivations as a direct replacement for atrazine. Because incorporation of different organic amendments (OAs) is a common practice in this crop, this study investigated the effects of different OAs, including urban sewage sludge, pou...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2008.0162
更新日期:2009-02-25 00:00:00
abstract::Erosion and runoff from pastures may lead to degradation of surface water. A 2-yr grazing study was conducted to quantify the effects of grazing management on sediment, phosphorus (P), and pathogen loading of streams in cool-season grass pastures. Six adjoining 12.1-ha pastures bisected by a stream in central Iowa wer...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2010.0524
更新日期:2011-07-01 00:00:00
abstract::Contamination of unfenced streams with P, sediments, and pathogenic bacteria from cattle (Bos taurus) activity may be affected by the availability of shade and alternative water sources. The objectives of this study were to evaluate water quality in two streams draining tall fescue (Festuca arundinacea Schreb.)-common...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2004.0335
更新日期:2005-11-07 00:00:00
abstract::Determination of sorption of hydrophilic, weakly sorbing organic compounds in soil by conventional batch methods using a slurried suspension is often prone to considerable errors because small changes in the solution concentration on equilibration must be accurately determined. This difficulty is exacerbated for compo...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2003.0423
更新日期:2005-05-11 00:00:00
abstract::Quantifying and managing diffuse P losses from small catchments or at the farm scale requires detailed knowledge of farming practices and their interaction with catchment processes. However, detailed knowledge may not be available and hence modeling is required. This paper demonstrates two approaches to developing too...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2007.0651
更新日期:2009-08-24 00:00:00
abstract::The Deckers Creek watershed in northern West Virginia (USA), containing a land area of 166 km2 (63 mi2), has a long history of industrial development and attendant environmental abuses from both land and water pollution practices. The water in Deckers Creek was sampled in 1974 at 29 locations along the main stem and r...
journal_title:Journal of environmental quality
pub_type: 历史文章,杂志文章
doi:10.2134/jeq2003.6540
更新日期:2003-03-01 00:00:00
abstract::The increasing number of polluted watersheds and water bodies with total maximum daily loads (TMDLs) has resulted in increased research to find methods that effectively and universally identify fecal pollution sources. A fundamental requirement to identify such methods is understanding the microbial and chemical proce...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2013.05.0190
更新日期:2014-01-01 00:00:00
abstract::Canada's National Agri-Environmental Standards Initiative sought to develop an environmental benchmark for low-level waterborne pathogen occurrence in agricultural watersheds. A field study collected 902 water samples from 27 sites in four intensive agricultural watersheds across Canada from 2005 to 2007. Four of the ...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2010.0253
更新日期:2012-01-01 00:00:00
abstract::Phosphorus transport from agricultural soils contributes to eutrophication of fresh waters. Computer modeling can help identify agricultural areas with high potential P transport. Most models use a constant extraction coefficient (i.e., the slope of the linear regression between filterable reactive phosphorus [FRP] in...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2005.0572
更新日期:2005-03-01 00:00:00
abstract::Standard methods for the evaluation of recreational water quality rely on generic bacterial indicators such as . However, does not provide enough information to determine fecal source or public health risk. The stsudy objective was to determine factors influencing the presence of and host-specific markers (HSM) from u...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2017.03.0105
更新日期:2017-09-01 00:00:00
abstract::Because organic sorption in soil may never reach equilibrium, a thin-disc flow nonequilibrium method may be helpful in understanding herbicide-soil interactions. This research was conducted to (i) determine the influence of incubation time on imazaquin [2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2004.5810
更新日期:2004-03-01 00:00:00
abstract::The widespread use of chromium (Cr) has a deleterious impact on the environment. A number of pathways, both biotic and abiotic in character, determine the fate and speciation of Cr in soils. Chromium exists in two predominant species in the environment: trivalent [(Cr(III)] and hexavalent [Cr(VI)]. Of these two forms,...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2011.0145
更新日期:2012-07-01 00:00:00
abstract::Riparian zones are recognized as landscape features that buffer streams from pollutants, particularly nitrogen. The objectives of this experiment were to (i) assess denitrification activity within a riparian zone and (ii) determine the influence of physical, chemical, and landscape features on denitrification. This ex...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2004.2367
更新日期:2004-11-01 00:00:00
abstract::This paper reports the use of a new technique, flow field-flow fractionation (FlFFF), for the characterization of soil sampled under grassland. FlFFF can be used to determine the fine colloidal material in the <1 microm fraction obtained by gravitational settling of 1% m/v soil suspensions. The aim of this work was to...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2007.0583
更新日期:2008-06-23 00:00:00
abstract::Man has land-applied societal nonhazardous wastes for centuries as a means of disposal and to improve the soil via the recycling of nutrients and the addition of organic matter. Nonhazardous wastes include a vast array of materials, including manures, biosolids, composts, wastewater effluents, food-processing wastes, ...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2005.0007
更新日期:2005-01-01 00:00:00
abstract::Managing biosolids from end-of-life municipal lagoons is a major challenge for many small communities where landfilling or spreading of biosolids on farmland is restricted. Contaminant removal via phytoextraction may be a viable remediation option for end-of-life lagoons in such communities. This study examined the ef...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2018.06.0230
更新日期:2018-11-01 00:00:00
abstract::Most farms have a centralized location to fill spray tanks with pesticides and to flush and clean application equipment. These sites, depending on the frequency of use, could be significant sources of surface and groundwater contamination. One approach to minimize this contamination is to install a treatment system, s...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2016.04.0124
更新日期:2018-03-01 00:00:00
abstract::Chloride contamination of rivers due to nonpoint sources is increasing throughout developed temperate regions due to road salt application in winter. We developed a river-network model of chloride loading to watersheds to estimate road salt application rates and investigated the meteorological factors that control riv...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2017.11.0418
更新日期:2018-07-01 00:00:00
abstract::Mechanistic, predictive equations for phosphorus (P) transport in runoff from manure-applied fields constitute a critical knowledge gap for developing nonpoint-source pollution models. We derived two simple equations to describe the P release from animal manure during a rainfall event-one based on first-order P desorp...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2003.0097
更新日期:2005-04-20 00:00:00
abstract::Pharmaceuticals used in animal feeding operations have been detected in various environmental settings. There is a growing concern about the impact on terrestrial and aquatic organisms and the development of antibiotic-resistant strains of microorganisms. Pharmaceutical use in milking cows is relatively limited compar...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2007.0371
更新日期:2008-09-01 00:00:00
abstract::Pharmaceutical compounds (PCs) and dissolved organic matter (DOM) are co-introduced into soils by irrigation with reclaimed wastewater. We targeted carbamazepine (CBZ) as a model compound to study the tertiary interactions between relatively polar PCs, DOM, and soil. Sorption-desorption behavior of CBZ was studied wit...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2010.0446
更新日期:2011-05-01 00:00:00
abstract::Long-term monitoring data from agricultural watersheds are needed to determine if efforts to reduce nutrient transport from crop and pasture land have been effective. Goodwater Creek Experimental Watershed (GCEW), located in northeastern Missouri, is a high-runoff-potential watershed dominated by claypan soils. The ob...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2014.02.0059
更新日期:2015-01-01 00:00:00
abstract::Quantum dots (QDs) of two different surface chemistries (carboxyl [COOH] and polyethylene glycol [PEG] modified) were utilized to determine the impact of surface functionality on QD mobility and distribution in Pseudomonas aeruginosa PAO1 biofilms. Confocal laser scanning microscopy was utilized to evaluate QD associa...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2009.0455
更新日期:2010-11-01 00:00:00
abstract::Growing nitrogen (N) catch crops can reduce NO(3)-N leaching after cultivating cereals. The objective of this study was to relate NO(3)-N leaching to variation in the uptake of N and the size and distribution of the root systems of different catch crops species. In a 3-yr lysimeter experiment, phacelia (Phacelia tanac...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2009.0306
更新日期:2010-04-13 00:00:00
abstract::The organophosphate insecticide phosmet [phosphorodithioic acid, s-((1,3-dihydro-1,3-dioxo-2H-isoindol-2yl)methyl), o,o-dimethyl ester] is used to control red-legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. Th...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2002.1630
更新日期:2002-09-01 00:00:00
abstract::Control methods are needed to abate NH losses from swine anaerobic lagoons to reduce the contribution of confined swine operations to air pollution. In a 15-mo meso-scale column study, we evaluated the effect of manure pretreatment on water quality, reduction of N losses, and sludge accumulation in swine lagoons using...
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2013.08.0330
更新日期:2014-07-01 00:00:00
abstract::Long-term application of phosphorus (P) with animal manure in amounts exceeding removal with crops leads to buildup of P in soil and to increasing risk of P loss to surface water and eutrophication. In most manures, the majority of P is held within inorganic forms, but in soil leachates organic P forms often dominate....
journal_title:Journal of environmental quality
pub_type: 杂志文章
doi:10.2134/jeq2006.0131
更新日期:2007-01-09 00:00:00