Microbial and antibiotic resistant constituents associated with biological aerosols and poultry litter within a commercial poultry house

Poultry are known to harbor antibiotic resistant and pathogenic bacteria, and as such poultry litter and poultry house air can be contaminated with these bacteria. However, the presence of antibiotic resistant bacteria in biological aerosols and litter is largely not understood. The purpose of this study was to determine the amount of aerosolized bacteria and endotoxin, particularly fecal indicators, staphylococci, and enterococci, associated with poultry house and outdoor air. Aerosol samples were collected at multiple locations on the farm and in the house. Antibiotic resistance was investigated using the Kirby Bauer method on selected isolates using twelve different antibiotics spanning both narrow to broad spectrums of effectiveness. Overall there was a cyclical increase in bacterial concentrations as flocks progressed from pre-flock to late-flock, with > 2 orders magnitude lower concentration during pre-flock periods (no chickens), in both the litter and aerosol samples. The house environment provided for significantly concentrated bacterial and endotoxin levels. It was estimated that Staphylococcus bacteria accounted for at least 90% of cultured aerobic bacteria and culture-independent 16S rRNA analyses demonstrated that significant population changes occurred from pre- to late-flock. Rarely was an isolate resistant to more than 4 antibiotic classes; however there was a trend upwards in overall resistance of enterococci as the flock cycle progressed. It appears that although levels of antibiotic resistant bacteria were highly concentrated within the house, levels were much lower outside of the house, and very little house escape occurred.     

Steroid hormones in biosolids and poultry litter: a comparison of potential environmental inputs

Steroid hormones can act as potent endocrine disruptors when released into the environment. The main sources of these chemicals are thought to be wastewater treatment plant discharges and waste from animal feeding operations. While these compounds have frequently been found in wastewater effluents, few studies have investigated biosolids or manure, which are routinely land applied, as potential sources. This study assessed the potential environmental contribution of steroid hormones from biosolids and chicken litter. Hormone concentrations in samples of limed biosolids collected at a waste treatment plant over a four year period ranged from < 2.5 to 21.7 ng/g dry weight for estrone (E1) and < 2.5 to 470 ng/g dry weight for progesterone. Chicken litter from 12 mid-Atlantic farms had averages of 41.4 ng/g dry weight E1, 63.4 ng/g dry weight progesterone, and 19.2 ng/g dry weight E1-sulfate (E1-S). Other analytes studied were 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), testosterone, E2-3-sulfate (E2-3-S), and E2-17-sulfate (E2-17-3).     

Fecal bacteria and sex hormones in soil and runoff from cropped watersheds amended with poultry litter

The application of poultry litter to agricultural fields can provide plant nutrients for crops and forage production, but fecal bacteria and the sex hormones estradiol and testosterone are components of litter that can be detrimental to the environment. Our objective was to determine if applications of poultry litter to small watersheds would contribute to the load of fecal bacteria and sex hormones to soil and runoff. We, therefore, investigated the fate and transport of fecal bacteria, estradiol and testosterone from surface applied poultry litter to four small cropped watersheds. Poultry litter was applied to meet the nitrogen requirements of pearl millet (Pennisetum glaucum L.) in 2000 and grain sorghum [Sorghum bicolor (L.) Moench] in 2001. Neither Salmonella nor Campylobacter were detected in the litter but the fecal indicator bacteria were. The average load of total coliforms, Escherichia coli, and fecal enterococci applied with the litter was 12.2, 11.9, and 12.7 log(10) cells ha(-1), respectively. The average load of estradiol and testosterone was 3.1 and 0.09 mg ha(-1), respectively. Runoff events first occurred 7 months after the first litter application in 2000, and 3 weeks after the second application in 2001. Only for the 25 July 2001 runoff event 3 weeks after the second litter application were the concentrations of total coliforms, E. coli, and fecal enterococci in runoff greater than background concentrations which were on average 5.2, 2.9, and 1.1 log(10) MPN 100 ml(-1), respectively. Average background levels of total coliforms, fecal enterococci, and E. coli in surface soil were 8.2, 7.9, and 3.5 log(10) cells kg(-1) soil. At the rate of litter application the concentrations of estradiol and testosterone in the litter did not appear to impact the background levels in the soil and runoff. Because concentrations of sex hormones in litter from other broiler operations are known to be greater than in the litter we applied, further study on the connection between concentrations of sex hormones in poultry litter and operational practices is recommended.     

Virus survival in solid waste leachates

Disposal of domestic solid waste either in open dumps or in sanitary landfills results in leachates which may find their way into groundwater aquifers. This study is concerned with the survival of microorganisms of sanitary significance, with particular emphasis on enteric viruses, in leachates produced by model disposal systems. Data are presented that indicate the presence of considerable amounts of human and animal feces in fresh domestic refuse. Significant numbers of coliforms, fecal coliforms, and fecal streptococci are present in refuse and also persist for weeks in the leachates produced.A method for the concentration and recovery of virus from relatively large volumes of leachate is evaluated. Viruses were sporadically recovered for periods up to 20 weeks from leachates generated by systems to which poliovirus was purposely introduced as well as from control systems. The leachates produced were shown not to be acutely toxic to poliovirus.     

Stability of organic matter in landfill leachates

Samples of grossly polluted groundwater and of leachate collected from wells or underdrains near solid waste disposal sites were subjected to extensive organic analyses. The soluble organics were concentrated, separated and characterized by membrane ultrafiltration, gelpermeation chromatography and analysis for functional groups and specific organics. Free volatile fatty acids represented the largest group of organics, and this fraction showed a rapid decrease with increasing age of the fill. The most stable group of organics with increasing age was a fulvic-like material with a relatively high carboxyl and aromatic hydroxyl group density. Increasing stability was further noted for carbohydrates, hydrolyzable amino acids and aromatic hydroxyl compounds in that order. Only leachate from a recently generating fill can be treated successfully by microbial processes because of its large biodegradable organic content; leachate from stabilized landfills is best treated by physical-chemical processes.     

Characterization of sanitary landfill leachates

Composition of leachates from some sanitary landfills in Norway and in the U.S.A. is described. The wide range of compositions found was mainly attributed to the efficiencies of preventing water to enter the fills.

Organic acids were found to contribute almost 90% of the total organics in the high strength leachates. The ratio of carbonaceous BOD to COD increased significantly with the concentrations of organics. Thus a better biological treatability is expected for the high strength leachates. High concentrations of nitrogen mainly as ammonia prevailed in all the samples while the concentrations of phosphorus were low. Of the heavy metals, iron were high in all the leachates, zinc was found to be the next highest. The concentrations of chromium, nickel, copper, cadmium and lead were low.     

Complexation characteristics of sanitary landfill leachates

The complexation of cadmium by organic components of sanitary landfill leachates was investigated using ion-exchange and specific ion electrode methods. Four Southern Ontario leachates were all found to be capable of complexing cadmium, to varying degrees. The complexing ability associated with certain molecular weight fractions was studied. In one leachate, complexation was mainly attributed to low (<500) molecular weight compounds. Their behaviour was consistent with that of simple carboxylic acids. In another leachate, high (> 10,000) molecular weight compounds contributed significantly to complexation. Their behaviour suggested that they might contain phenolic hydroxyl groups having a stability constant towards cadmium of the order of 10⁵. It was concluded that the role of complexation in determining the fate of metals in sanitary landfill leachates depended upon several factors whose importance had not yet been adequately investigated or reported in the literature.     

Fluorescence of leachates from three contrasting landfills

Landfill leachates are composed of a complex mixture of degradation products including dissolved organic matter, which includes a wide range of potentially fluorescent organic molecules and compounds. Here we investigate the excitation-emission matrix fluorescence of landfill leachates from three contrasting landfill sites. Landfill fluorescence properties are all characterized by intense fluorescence at lambda(ex) =220-230nm, and lambda(em) =340-370nm which we suggest derives from fluorescent components of the Xenobiotic Organic Matter fraction such as naphthalene, as well as at lambda(ex) =320-360nm, and lambda(em) =400-470nm from a higher molecular weight fulvic-like fraction. Landfill leachates are characterized by intense fluorescence, with approximately 10(2) intensity units of fluorescence at lambda(ex)=220-230nm, and lambda(em)=340-370nmmg(-1) of total organic carbon, demonstrating leachate detection limits of <0.1mgl(-1) total organic carbon. We demonstrate that for all landfill sites, leachate fluorescence intensity has a strong correlation with ground water quality determinants ammonia, total organic carbon and biochemical oxygen demand. We investigate both within-site and between-site leachate fluorescence properties, and demonstrate that although there is significant within-site variability, leachates from all 3 sites can be statistically discriminated using just fluorescence properties (65% success rate) or with a combination of fluorescence and basic geochemical parameters (85%). Our findings suggest that fluorescence can be used as a rapid and sensitive tracer of leachate contamination of ground water, as well as help discriminate, together with geochemical determinants, leachates from different landfill sources.     

Photodegradation of three stormwater biocides

Photodegradation of carbendazim, diuron and terbutryn was investigated at controlled laboratory conditions under UV light and under natural sunlight. Demineralized water and two different waters from stormwater retention ponds were used. An observed decline in biocide concentration was related to the accumulated light energy during the degradation time. Diuron and terbutryn were degradable under UV light following 1^st order degradation kinetics, while no significant decrease of carbendazim was observed throughout the duration of experiments. Photodegradation of diuron and terbutryn was slightly faster in demineralized water compared with pond water. The outdoors experiments showed limited degradation of the compounds for the duration of the test (8–17 days). The results emphasize the importance of water type, the wavelength and energy of the light when investigating pollutant’s photo fate. Also, this study indicates that photodegradation is not a major process contributing to the removal of carbendazim, diuron and terbutryn in stormwater retention ponds.     

Phthalic acid esters in dissolved fractions of landfill leachates

The distribution of phthalic acid esters (PAEs) (including diisobutylphthalate (DIBP), di-n-butylphthalate (DnBP) and bis(2-ethyl)hexylphthalate (DEHP)) in dissolved organic matter (DOM) fractions of leachates from sanitary or bioreactor landfills was evaluated. The leachate DOM was fractionated into humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) fractions. Measurements showed that the PAEs were bound mostly to the HA fraction in leachate, regardless of their landfill age or the presence of leachate recirculation. The PAEs affinity for HA and FA differed considerably relative to the sorption coefficients reported for model compounds. Molecular weight of DOM correlated with PAEs partition in collected leachate samples fractions while aromaticity was a poor predictor. Based on the presence of phenolic, carboxyl or amide groups in DOM fractions, hydrogen bonding is likely to be involved in interactions between PAEs and leachate DOM. The peptide groups, particularly presented in HA fracion, might explain the strong affinity of PAEs for HA. The fluorescence excitation emission matrix contour plots showed that the HyI fractions shared certain similarities with humic substances in terms of molecular structure, which may be one reason why PAEs exhibited a clear sorption to the HyI fractions.     

Rain water leachates of heavy metals in road surface sediments

Samples of street surface and roadside gutter sediments within a separately sewered catchment in N.W. London have been analysed for heavy metal contamination. Particle size distributions are presented and the removal efficiency of metal species demonstrated for various street cleaning procedures. Laboratory sorption and desorption studies are described and solution concentrations are obtained for Pb, Cd and Mn.Solubility curves are typically variable with time with Mn showing the strongest tendency to attain equilibrium. No obvious dependence of metal concentrations on grain size is readily apparent although Cd tends to desorb more rapidly from size fractions greater than 250 μm.     

Photodegradation of estrone and 17beta-estradiol in water

The TiO(2)-assisted photodegradation of two natural female hormones, estrone (E1) and 17beta-estradiol (E2), was investigated in two UV-photo-reactors, followed by solid-phase extraction and analysis by gas chromatography-mass spectrometry (GC-MS). The degradation of E1 and E2 in both reactors followed the pseudo-first-order kinetics. In reactor 1 (150W), 97% of compounds were degraded within 4h of irradiation. Even more rapid degradation was observed in reactor 2 (15W) where 98% of both compounds disappeared within 1h, due to the shorter wavelength of UV-light in reactor 2 (fixed at 253nm) than reactor 1 (238-579nm). The influences of different initial chemical concentrations, pH value, the presence of dissolved organic matter and hydrogen dioxide, and the catalyst concentration on the degradation rate of E1 and E2 in aqueous solutions were investigated. The results show that the extent of photo-induced degradation of E1 and E2 strongly depends on the water constituents in solution. The degradation rate was increased when pH value was increased from 2 to 7.6, beyond which the degradation rate started to decrease. The presence of humic acid enhanced the degradation of E1 and E2 in both reactors as a result of photosensitisation effect of humic acid chromophore. The degradation rate increased with an increase in H(2)O(2) concentration. The degradation rate was also enhanced by increasing catalyst concentration up to 2g/l. The findings therefore suggest that photocatalysis can be a very effective method of rapidly removing certain EDCs from water.     

Chronic and reproduction studies in rats exposed to gasifier ash leachates

Ash from the coal gasification process contains a broad spectrum of elements which through leaching (gasifier ash leachates) may enter into the environment. The health effect of such leachates i.e. complex mixtures of inorganic elements is insufficiently known. We investigated the effect of gasifier ash leachates in a chronic-(9-month) and in a three-generation reproduction study. The leachates were prepared weekly by water extraction of ash from a Lurgi coal gasification plant in Yugoslavia, and given to experimental animals instead of drinking water. In the chronic experiment exposed animals showed no changes in mortality rate, haematological findings, concentration of Fe, Zn, Mn in kidneys, liver, testicles and femur, as well as in femur composition and morphometry, gross pathology and organ histology. In the reproduction study the number of pregnancies, weight and number of newborns, and concentration of Fe, Zn, Mn in carcasses of sucklings were the same in control and experimental animals.     

Assessment of metal content and toxicity of leachates from teapots

Metallic teapots traditionally used in Morocco were investigated for release of toxic metals from the teapots and their toxicity, as determined by MetPAD, a bacterial toxicity test that is specific for heavy metal toxicity. Our data show that some teapots were non-toxic while a few others were highly toxic, as shown by MetPAD. Tea addition reduced somewhat heavy metal toxicity due possibly to the complexing ability of tea. Chemical analysis of teapot leachates showed that some contained zinc and copper. Teapot No. 5, which showed the highest toxicity, also displayed the highest Zn concentration (7.39 mg/l), confirming the toxicity data. Based on estimates of tea consumption in Morocco, we showed that the extra daily burden of Zn ranged from 1.75 to 4.2 mg/day, assuming the maximum zinc concentration of 7.4 mg/l, as found in our study. This represents 3.5-8% of the LOAEL for zinc of 50 mg/day and would not be important as compared to other sources zinc intake.     

Removal of non-biodegradable organic matter from landfill leachates by adsorption

Leachates produced at the La Zoreda landfill in Asturias, Spain, were recirculated through a simulated landfill pilot plant. Prior to recirculation, three loads of different amounts of Municipal Solid Waste (MSW) were added to the plant, forming in this way consecutive layers. When anaerobic digestion was almost completed, the leachates from the landfill were recirculated. After recirculation, a new load of MSW was added and two new recirculations were carried out. The organic load of the three landfill leachates recirculated through the anaerobic pilot plant decreased from initial values of 5108, 3782 and 2560 mg/l to values of between 1500 and 1600 mg/l. Despite achieving reductions in the organic load of the leachate, a residual organic load still remained that was composed of non-biodegradable organic constituents such as humic substances. Similar values of the chemical oxygen demand (COD) were obtained when the landfill leachate was treated by a pressurised anoxic-aerobic process followed by ultrafiltration. After recirculation through the pilot plant, physico-chemical treatment was carried out to reduce the COD of the leachate. The pH of the leachate was decreased to a value of 1.5 to precipitate the humic fraction, obtaining a reduction in COD of about 13.5%. The supernatant liquid was treated with activated carbon and different resins, XAD-8, XAD-4 and IR-120. Activated carbon presented the highest adsorption capacities, obtaining COD values for the treated leachate in the order of 200mg/l. Similar results were obtained when treating with activated carbon, the leachate from the biological treatment plant at the La Zoreda landfill; in this case without decreasing the pH.     

Photodegradation of psychiatric pharmaceuticals in aquatic environments--kinetics and photodegradation products

Benzodiazepines are widely consumed psychiatric pharmaceuticals which are frequently detected in the environment. The environmental persistence and fate of these pharmaceuticals as well as their degradation products is of high relevance and it is, yet, scarcely elucidated. In this study, the relevance of photodegradation processes on the environmental persistence of four benzodiazepines (oxazepam, diazepam, lorazepam and alprazolam) was investigated. Benzodiazepines were irradiated under simulated solar irradiation and direct and indirect (together with three different fractions of humic substances) photodegradation kinetics were determined. Lorazepam was shown to be quickly photodegradated by direct solar radiation, with a half-life time lower than one summer sunny day. On the contrary, oxazepam, diazepam and alprazolam showed to be highly resistant to photodegradation with half-life times of 4, 7 and 228 summer sunny days, respectively. Apparent indirect and direct photodegradation rates are of the same order of magnitude. However, humic acids were consistently responsible for a decrease in the photodegradation rates while fulvic acids and XAD4 fraction caused an enhancement of the photodegradation. Overall, the results highlight that photodegradation might not be an efficient pathway to prevent the aquatic environmental accumulation of oxazepam, diazepam and alprazolam. Also, nineteen direct photodegradation products were identified by electrospray mass spectrometry, the majority of which are newly identified photoproducts. This identification is crucial to a more complete understanding of the environmental impact of benzodiazepines in aquatic systems.     

Mono- and diesters from o-phthalic acid in leachates from different European landfills

Leachates from 17 different landfills in Europe were analysed with respect to phthalates, i.e. phthalic acid diesters (PAEs) and their degradation products phthalic acid monoesters (PMEs) and ortho-phthalic acid (PA). Diesters are ubiquitous and the human possible exposure and potential to human health and environment has put them in focus. The aim of this study was to elucidate whether monoesters and phthalic acid could be traced in landfill leachates and in what concentrations they may be found. The results showed that phthalates were present in the majority of the leachates investigated. The monoesters appeared from 1 to 20 microg/L and phthalic acid 2-880 microg/L (one divergent value of 19 mg phthalic acid/L). Their parental diesters were observed from 1 to 460 microg/L. These observed occurrences of degradation products, of all diesters studied, support that they are degraded under the landfill conditions covered by this study. Thus, we have presented strong evidences to conclude that microorganisms in landfills degrade diesters released from formulations in a variety of products, including polyvinyl chloride (PVC) species.     

Photodegradation of 2,4-dichlorophenoxyacetic acid in various iron-mediated oxidation systems

The oxidation of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) by different iron-mediated processes, with or without the presence of ultraviolet (at 253.7 nm) and oxalate, was investigated and compared. The initial decay rate and the overall removal percentage were used as the performance indexes. To extensively explore the associated processes, the following combinations or blank systems were investigated: UV radiation only, Fe(2+)/H(2)O(2), Fe(2+)/H(2)O(2)/UV, ferrous oxalate/H(2)O(2), ferrous oxalate/H(2)O(2)/UV, Fe(3+)/H(2)O(2), Fe(3+)/H(2)O(2)/UV, ferrioxalate/H(2)O(2), and ferrioxalate/H(2)O(2)/UV. This study showed that the degradation of 2,4-D by sole UV or dark processes (without UV) is generally slow, except by the conventional Fenton's process (Fe(2+)/H(2)O(2)). However, these slow reactions can be accelerated by exposure to UV irradiation, which can increase the initial 2,4-D decay rate from ten to more than one hundred times. Furthermore, if the reaction is initiated by ferrous oxalate or ferrioxalate instead of Fe(2+) or Fe(3+) ions, the rates can be further improved, because of the higher light sensitivity of the organometallic complexes. These reactions were also found sensitive to the initial hydrogen peroxide concentration. The competition of hydroxyl free radicals by the primary intermediate, 2,4-dichlorophenol, was also observed.     

Occurrence and distribution of organotin compounds in leachates and biogases from municipal landfills

The occurrence and distribution of organotin compounds (OTC) in effluents from two different landfills were investigated through the combination of three different analytical methodologies. In this way, the determination of the volatile OTC in biogases, the dissolved volatile and dissolved ionic organotin species in leachates was carried out using these complementary approaches. In leachates, up to nine OTC (i.e. methyltin, ethyltin, butyltin and mixed methyl-ethyltins) were detected at concentrations ranging from 0.01 to 6.5 microg (Sn)L(-1), which represents 1-38% of the total tin concentration. In biogases, five volatile tin species (i.e. methyltin, mixed methyl-ethyltin and ethyltin) were determined at significant concentrations reaching up to 25 microg (Sn)m(-3). The occurrence of the overall identified species is explained by both organotin-containing waste and endogenous alkylation pathways. Two parameters seem to significantly influence the effluent OTC composition: first, wet depositions both induce leachate dilution and alter methylation/ethylation mechanisms; second, evolution of the waste degradation stage yields different volatilisation mechanisms (i.e. permethylation or perethylation). The results obtained in this work outline the diversity and variability of the organotin contamination routes provided by multiple pathways. These phenomena can lead to the release of biologically harmful species in the environment if no efficient effluent treatment is applied.     

Photodegradation of the antibiotics nitroimidazoles in aqueous solution by ultraviolet radiation

The objective of this study was to analyze the efficacy of ultraviolet (UV) radiation in the direct photodegradation of nitroimidazoles. For this purpose, i) a kinetic study was performed, determining the quantum yield of the process; and ii) the influence of the different operational variables was analyzed (initial concentration of antibiotic, pH, presence of natural organic matter compounds, and chemical composition of water), and the time course of total organic carbon (TOC) concentration and toxicity during nitroimidazole photodegradation was studied. The very low quantum yields obtained for the four nitroimidazoles are responsible for the low efficacy of the quantum process during direct photon absorption in nitroimidazole phototransformation. The R₂₅₄ values obtained show that the dose habitually used for water disinfection is not sufficient to remove this type of pharmaceutical; therefore, higher doses of UV irradiation or longer exposure times are required for their removal. The time course of TOC and toxicity during direct photodegradation (in both ultrapure and real water) shows that oxidation by-products are not oxidized to CO₂ to the desired extent, generating oxidation by-products that are more toxic than the initial product. The concentration of nitroimidazoles has a major effect on their photodegradation rate. The study of the influence of pH on the values of parameters ? (molar absorption coefficient) and k′_E (photodegradation rate constant) showed no general trend in the behavior of nitroimidazoles as a function of the solution pH. The components of natural organic matter, gallic acid (GAL), tannic acid (TAN) and humic acid (HUM), may act as promoters and/or inhibitors of OH· radicals via photoproduction of H₂O₂. The effect of GAL on the metronidazole (MNZ) degradation rate markedly differed from that of TAN or HUM, with a higher rate at low GAL concentrations. Differences in MNZ degradation rate among waters with different chemical composition are not very marked, although the rate is slightly lower in wastewaters, mainly due to the UV radiation filter effect of this type of water.