Determination of veterinary pharmaceuticals in poultry litter and soil by methanol extraction and liquid chromatography-tandem mass spectrometry

Pharmaceuticals are emerging contaminants with potential risks to the environment and human health. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for determination of the antimicrobials virginiamycin, monensin, salinomycin, narasin and nicarbazin in poultry litter and soil. This method involves methanol extraction and clean-up of extracts through glass microfibre filters, introduction of the extracts and separation of compounds on a Zorbax Eclipse XDB C8 column, and compound detection in a Quattro Micro Micromass spectrometer. For litter samples, Method Detection Limits ranged from 0.1–0.6 μg Kg^{? 1}, while Limits of Quantitation (LOQs) were 2, 1, 0.4, 1 and 2 μg Kg^{? 1} for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. For soil samples calculated LOQs were 2, 3, 1, 1, and 1 μg Kg^{? 1} for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. Application of the LC-MS-MS method for detection of veterinary pharmaceuticals in litter collected from commercial poultry farms showed that compounds were present at concentrations ranging from 10–11,000 μg Kg^{? 1}.     

Quantification of ionophores in aged poultry litter using liquid chromatography tandem mass spectrometry

Veterinary anticoccidials, biochemically known as ionophores, are widely used in poultry feed at therapeutic levels to treat Coccidiosis and at sub-therapeutic levels for growth- promotion. Commonly used ionophores in the US poultry industry are monensin, salinomycin, lasalocid and narasin. There is an increasing concern regarding the persistence of these anticoccidials in the environment. However, little attention has been directed to methods development for quantitatively measuring ionophores in complex environmental matrices such as poultry litters that are land applied. Here, we describe a rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method developed for simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in aged poultry litter samples. Results show significant level of monensin (97.8 ± 3.2 μg kg^?1), lasalocid (19.2 ± 6.6 μg kg^?1), salinomycin (70 ± 2.7 μg kg^?1) and narasin (57.3 ± 2.6 μg kg^?1) in poultry litter stored for over three years at < 5°C. Our findings indicate that even after several years of unmanaged storage of poultry litter, ionophores may continue to persist in this matrix, raising the possibility of prolonged release into the environment.     

Quantification of ionophores in aged poultry litter using liquid chromatography tandem mass spectrometry

Veterinary anticoccidials, biochemically known as ionophores, are widely used in poultry feed at therapeutic levels to treat Coccidiosis and at sub-therapeutic levels for growth- promotion. Commonly used ionophores in the US poultry industry are monensin, salinomycin, lasalocid and narasin. There is an increasing concern regarding the persistence of these anticoccidials in the environment. However, little attention has been directed to methods development for quantitatively measuring ionophores in complex environmental matrices such as poultry litters that are land applied. Here, we describe a rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method developed for simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in aged poultry litter samples. Results show significant level of monensin (97.8 ± 3.2?μg kg(-1)), lasalocid (19.2 ± 6.6?μg kg(-1)), salinomycin (70 ± 2.7?μg kg(-1)) and narasin (57.3 ± 2.6?μg kg(-1)) in poultry litter stored for over three years at < 5°C. Our findings indicate that even after several years of unmanaged storage of poultry litter, ionophores may continue to persist in this matrix, raising the possibility of prolonged release into the environment.     

Lead concentration increase in the hepatic and gill soluble fractions of European chub (Squalius cephalus)—an indicator of increased Pb exposure from the river water

Purpose

To examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1???g?L^?1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2???g?L^?1; EPCEU (Official J L 348:84, 2008)), would result in Pb accumulation in selected fish tissues.

Methods

Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia?CSlovenia).

Results

At the site with increased dissolved Pb in the river water, soluble gill Pb levels (17.3???g?L^?1) were approximately 20 times higher compared to uncontaminated sites (0.85???g?L^?1), whereas the ratio between contaminated (18.1???g?L^?1) and uncontaminated sites (1.17???g?L^?1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex, or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects.

Conclusions

The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters.     

Occurrence of endocrine disrupters and selected pharmaceuticals in Aisonas River (Greece) and environmental risk assessment using hazard indexes

Purpose

The presence of four phenolic endocrine disrupting compounds (EDCs: nonylphenol [NP], NP monoethoxylate[NP1EO], bisphenol A [BPA], triclosan, [TCS]) and four nonsteroidal anti-inflammatory drugs (NSAIDs: ibuprofen[IBF], ketoprofen [KFN], naproxen [NPX], diclofenac [DCF]) in a Greek river receiving treated municipal wastewater was investigated in this study.

Methods

Samples were taken from four different points of the river and from the outlet of a sewage treatment plant (STP) during six sampling campaigns, and they were analyzed using gas chromatography?Cmass spectrometry.

Results

According to the results, EDCs were detected in almost all samples, whereas NSAIDs were detected mainly in wastewater and in the part of the river that receives wastewater from the STP. Among the target compounds, the highest mean concentrations in the river were detected for NP (1,345?ng?L^?1) and DCF (432?ng?L^?1). Calculation of daily loads of the target compounds showed that STP seems to be the major source of NSAIDs to the river, whereas other sources contribute significantly to the occurrence of EDCs. The environmental risk due to the presence of target compounds in river water was estimated, calculating risk quotients for different aquatic organisms (algae, daphnids, and fish). Results denoted the possible threat for the aquatic environment due to the presence of NP and TCS in the river.     

Aquatic ecotoxicity assessment of a new natural formicide

Background, aim and scope

Agrochemicals could reach aquatic ecosystems and damage ecosystem functionality. Natural formicide could be an alternative to use in comparison with the more toxic formicides available on the market. Thus, the objective of this study was to assess the ecotoxicity of the new natural formicide Macex? with a battery of classical aquatic ecotoxicity tests.

Material and methods

Bacteria (Aliivibrio fischeri), algae (Pseudokirchneriella subcapitata), hydra (Hydra attenuata), daphnids (Daphnia magna), and fish (Danio rerio) tests were performed in accordance with international standardized methodologies.

Results

In the range of formicide concentrations tested (0.03 to 2.0?g?L^?1) EC₅₀ values varied from 0.49 to >2.0?g?L^?1, with P. subcapitata being the most sensitive species and H. attenuata and D. rerio the most tolerant species to this product in aqueous solutions.

Conclusions

This new formicide preparation can be classed as a product of low toxicity compared to the aquatic ecotoxicity of the most common commercialized formicides.     

Reduction of dinitrotoluene sulfonates in TNT red water using nanoscale zerovalent iron particles

Purpose

This research was designed to investigate the feasibility of converting the dinitrotoluene sulfonates (DNTS) in TNT red water into the corresponding aromatic amino compounds using nanoscale zerovalent iron (NZVI).

Methods

NZVI particles were simultaneously synthesized and stabilized by sodium borohydride reduction in a nondeoxygenated system. The morphology, elemental content, specific surface area, and crystal properties of the NZVI were characterized before and after the reaction by environmental scanning electron microscope; energy dispersive X-ray; Brunauer, Emmett, and Teller; and X-ray diffraction, respectively. The reduction process was conducted at pH?=?6.3 at ambient temperature. The efficiency of the NZVI-mediated DNTS reduction process was monitored by HPLC, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses.

Results

The properties of the NZVI particles prepared were found to be similar to those obtained through oxygen-free preparation and inert stabilization processes. Both 2,4-DNT-3-sulfonate (2,220?mg?L^?1) and 2,4-DNT-5-sulfonate (3,270?mg?L^?1) in TNT red water underwent a pseudo-first-order transformation when mixed with NZVI at room temperature and near-neutral pH. Their observed rate constants were 0.11 and 0.30?min^?1, respectively. Within 1?h of processing, more than 99% of DNTS was converted by NZVI-mediated reduction into the corresponding diaminotoluene sulfonates.

Conclusions

NZVI can be simultaneously prepared and stabilized in a nondeoxygenated system. NZVI reduction is a highly efficient method for the conversion of DNTS into the corresponding diaminotoluene sulfonates under near-neutral pH conditions. Therefore, NZVI reduction may be useful in the treatment of TNT red water and subsequent recovery of diaminotoluene from explosive wastewater.     

Bioremediation of chromium by novel strains Enterobacter aerogenes T2 and Acinetobacter sp. PD 12 S2

Purpose

This study had an objective to identify the most potent chromium-resistant bacteria isolated from tannery effluent and apply them for bioremediation of chromium in tannery effluents.

Methods

Two such strains (previously characterized and identified by us)??Enterobacter aerogenes (NCBI GenBank USA Accession no. GU265554) and Acinetobacter sp. PD 12 (NCBI GenBank USA Accession no. GU084179)??showed powerful chromium resistivity and bioremediation capabilities among many stains isolated from tannery waste. Parameters such as pH, concentration of hexavalent chromium or Cr (VI), and inoculum volume were varied to observe optimum bioconversion and bioaccumulation of Cr (VI) when the said strains were grown in M9 minimal salt media. E. aerogenes was used to remediate chromium from tannery effluents in a laboratory level experiment.

Results

Observation by Scanning Electron Microscope and chromium peak in Energy Dispersive X-ray Spectroscopic microanalysis revealed that E. aerogenes helped remediate a moderate amount of Cr (VI) (8?C16?mg?L^?1) over a wide range of pH values at 35?C37°C (within 26.05?h). High inoculum percentage of Acinetobacter sp. PD 12 also enabled bioremediation of 8?C16?mg?L^?1 of Cr (VI) over a wide range of temperature (25?C37°C), mainly at pH?7 (within 63.28?h). The experiment with real tannery effluent gave very encouraging results.

Conclusion

The strain E. aerogenes can be used in bioremediation of Cr (VI) since it could work in actual environmental conditions with extraordinarily high capacity.     

Removal of arsenate from groundwater by electrocoagulation method

Purpose

Arsenic, a toxic metalloid in drinking water, has become a major threat for human beings and other organisms. In the present work, attempts have been made to remove arsenate from the synthetic as well as natural water of Ballia district, India by electrocoagulation method. Efforts have also been made to optimize the various parameters such as initial arsenate concentration, pH, applied voltage, processing time, and working temperature.

Method

Electrocoagulation is a fast, inexpensive, selective, accurate, reproducible, and eco-friendly method for arsenate removal from groundwater. The present paper describes an electrocoagulation method for arsenate removal from groundwater using iron and zinc as anode and cathode, respectively.

Results

The maximum removal of arsenate was 98.8% at 2.0?mg?L^?1, 7.0, 3.0?V, 10.0?min, and 30°C as arsenate concentration, pH, applied voltage, processing time, and working temperature, respectively. Relative standard deviation, coefficient of determination (r ²), and confidence limits were varied from 1.50% to 1.59%, 0.9996% to 0.9998%, and 96.0% to 99.0%, respectively. The treated water was clear, colorless, and odorless without any secondary contamination. The developed and validated method was applied for arsenate removal of two samples of groundwater of Ballia district, U.P., India, having 0.563 to 0.805?mg?L^?1, arsenate concentrations.

Conclusions

The reported method is capable for the removal of arsenate completely (100% removal) from groundwater of Ballia district. There was no change in the groundwater quality after the removal of arsenate. The treated water was safe for drinking, bathing, and recreation purposes. Therefore, this method may be the choice of arsenate removal from natural groundwater.     

Occurrence of cyclophosphamide and epirubicin in wastewaters by direct injection analysis–liquid chromatography–high-resolution mass spectrometry

Background, aim, and scope

According to the high incidence of cancer worldwide, the amount of cytostatic drugs administered to patients has increased. These compounds are excreted to wastewaters, and therefore become potential water contaminants. At this stage, very little is known on the presence and elimination of cytostatic compounds in wastewater treatment plants (WWTP). The aim of this study was to develop a liquid chromatography?Chigh-resolution mass spectrometry (LC?COrbitrap?CMS) method for the determination of cyclophosphamide and epirubicin in wastewaters. These compounds represent two outmost used cytostatic agents.

Materials and methods

Extraction and analytical conditions were optimized for cyclophosphamide and epirubicin in wastewater. Both solid-phase extraction using Oasis 200?mg hydrophilic?Clipophilic balanced (HLB) cartridges and direct injection analysis were evaluated. Mass spectral characterization and fragmentation conditions were optimized at 50,000 resolving power (full width at half maximum, m/z 200) to obtain maximum sensitivity and identification performance. Quality parameters (recoveries, limits of detection, and repetitivity) of the methods developed were determined, and best performance was obtained with direct water analysis of the centrifuged wastewater. Finally, this method was applied to determine the presence of cyclophosphamide and epirubicin in wastewaters from a hospital effluent, an urban effluent, and influents and effluents from three WWTP.

Results and discussion

Cyclophosphamide and epirubicin were recovered after 50?mL preconcentration on solid-phase extraction 200?mg Oasis HLB cartridges (87% and 37%, respectively), and no breakthrough was observed by extracting 500?mL of water. Limits of detection were of 0.35 and 2.77?ng/L for cyclophosphamide and epirubicin, respectively. On the other hand, direct injection of water spiked at 1???g/L provided recoveries of 107% for cyclophosphamide and 44% for epirubicin and limits of detection from 3.1 to 85?ng?L^?1, respectively. The analysis of wastewaters using direct injection analysis revealed the presence of cyclophosphamide and epirubicin in WWTP influents and hospital and urban effluents at levels ranging from 5.73 to 24.8???g?L^?1.

Conclusions

The results obtained in this study demonstrate the capability of LC?COrbitrap?CMS for accurate trace analysis of these very polar contaminants. This method permitted to identify cyclophosphamide and epirubicin in wastewaters and influents of WWTP, but no traces were detected in WWTP effluents. The methodology herein developed is sensitive and robust and applicable for screening of a large number of samples since no preconcentration is needed.     

Cloud point extraction for the preconcentration of palladium and lead in environmental samples and determination by flow injection flame atomic absorption spectrometry

Purpose

An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS).

Method

The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6?mL?min^?1. The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH?6 and eluted with 1.0?mol?L^?1 nitric acid in methanol at a flow rate of 1.1?mL?min^?1 directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized.

Results

Under the optimized conditions for 25?mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4?ng?mL^?1 for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples.

Conclusions

Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard.     

Removal of cyanotoxins from surface water resources using reusable molecularly imprinted polymer adsorbents

Introduction

Microcystins (MCs; cyclic heptapeptides) are produced by freshwater cyanobacteria and cause public health concern in potable water supplies. There are more than 60 types of MCs identified to date, of which MC-LR is the most common found worldwide. For MC-LR, the WHO has established a threshold value of 1???g?L^?1 for drinking water. The present MCs removal methods such as coagulation, flocculation, adsorption, and filtration showed low efficiency for removing dissolved MC fraction from surface waters to the stipulated limit prescribed by WHO based on MC health impacts. The search for cost-effective and efficient removal method is still warranted for remediation of dissolved MC-LR-contaminated water resources.

Materials and methods

Molecularly imprinted polymer (MIP) adsorbent has been prepared using non-covalent imprinting approach. Using MC-LR as a template, itaconic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross-linking monomer, a MIP has been synthesized. Computer simulations were used to design effective binding sites for MC-LR binding in aqueous solutions. Batch binding adsorption assay was followed to determine binding capacity of MIP under the influence of environmental parameters such as total dissolved solids and pH.

Results and discussion

The adsorptive removal of MC-LR from lake water has been investigated using MIPs. The MIP showed excellent adsorption potential toward MC-LR in aqueous solutions with a binding capacity of 3.64???g?mg^?1 which is about 60% and 70% more than the commercially used powdered activated carbon (PAC) and resin XAD, respectively. Environmental parameters such as total organic carbon (represented as chemical oxygen demand (COD)) and total dissolved solids (TDS) showed no significant interference up to 300?mg?L^?1 for MC-LR removal from lake water samples. It was found that the binding sites on PAC and XAD have more affinity toward COD and TDS than the MC-LR. Further, the adsorption capacity of the MIP was evaluated rigorously by its repeated contact with fresh lake water, and it was found that the adsorption capacity of the MIP did not change even after seven adsorption/desorption cycles. The contaminated water of MC-LR (1.0???g?L^?1) of 3,640?L could be treated by 1?g of MIP with an estimated cost of US $1.5.

Conclusions

The adsorption capacity of the MIP is 40% more than commercially used PAC and resins and also the polymer showed reusable potential which is one of the important criteria in selection of cyanotoxins remediation methods.     

Heterogeneous photocatalytic degradation of methyl orange in schwertmannite/oxalate suspension under UV irradiation

Introduction

Schwertmannite was synthesized through an oxidation of FeSO₄ by Acidithiobacillus ferrooxidans LX5 cell suspension at an initial pH?2.5 and 28°C for 3?days and characterized using X-ray diffraction spectroscopy and scanning electron microscope. The schwertmannite photocatalytic degradation of methyl orange (MO) by oxalate was investigated at different initial pH values, concentrations of schwertmannite, oxalate, and MO.

Results

The results demonstrated that photodegradation of MO in the presence of schwertmannite or oxalate alone was very weak. However, the removal of MO was significantly enhanced when schwertmannite and oxalate coexisted in the reaction system. Low pH (4 or less) was beneficial to the degradation of MO. The optimal doses of schwertmannite and oxalate were 0.2?g?L^?1 and 2?mM, respectively. Hydroxyl radicals (·OH) and Fe(II), the intermediate products, were also examined during the reaction to explore their correlation with the degradation of MO.

Conclusion

A possible mechanism for the photocatalytic decomposition of MO in the study was proposed. The formation of Fe(III)-oxalate complexes on the surface of schwertmannite was a precursor of H₂O₂ and Fe(II) production, further leading to the yield of ·OH responsible for the decomposition of MO.     

Occurrence of psychoactive compounds and their metabolites in groundwater downgradient of a decommissioned sewage farm in Berlin (Germany)

Purpose

Psychoactive compounds??meprobamate, pyrithyldione, primidone, and its metabolites, phenobarbital, and phenylethylmalonamide??were detected in groundwater within the catchment area of a drinking water treatment plant located downgradient of a former sewage farm in Berlin, Germany. The aim of this study was to investigate the distribution of the psychoactive compounds in anoxic groundwater and to assess the risk of drinking water contamination. Groundwater age was determined to achieve a better understanding of present hydrogeological conditions.

Methods

A large number of observation and production wells were sampled. Samples were analyzed using solid-phase extraction and ultrahigh-performance liquid chromatography?Ctandem mass spectrometry. Groundwater age was estimated using the helium?Ctritium (³He?C³H) dating method.

Results

Concentrations of psychoactive compounds up to 1???g/L were encountered in the contamination plume. Generally, concentrations of phenobarbital and meprobamate were the highest. Elevated concentrations of the analytes were also detected in raw water from abstraction wells located approximately 2.5?km downgradient of the former sewage farm. Concentrations in the final drinking water were below the limit of quantification owing to dilution. The age of shallow groundwater samples ranged from years to a decade, whereas groundwater was up to four decades old at 40?m below ground. Concentrations of the compounds increased with groundwater age.

Conclusions

Elevated concentrations of psychoactive drugs indicate a strong persistence of these compounds in the environment under anoxic aquifer conditions. Results suggest that the heritage of sewage irrigation will affect raw water quality in the area for decades. Therefore, further monitoring of raw and final drinking water is recommended to ensure that contaminant concentrations remain below the health-based precautionary value.     

Aquatic photochemistry of paracetamol in the presence of dissolved organic chromophoric material and nitrate

Purpose

This study contains some new findings connected to the photolysis of the drug paracetamol (hereinafter APAP) especially in light of estimating natural conditions, and it will offer information to better evaluate environmental problems connected with this widely used analgesic agent. Only a few studies, so far, have focussed on the photodegradation process of APAP in the natural environment, and the question about the role of the colored/chromophoric dissolved organic matter (CDOM) and nitrate (NO ₃ ^? ) as photoinductors is almost open.

Methods

APAP dissolved in freshwater and pure laboratory water in the presence and absence of CDOM and NO ₃ ^? ions was irradiated using weak-energy photon energies simulating natural conditions.

Results

CDOM and NO ₃ ^? as photoinductors produced only the slow phototransformation of APAP under weak energy radiation, and APAP seemed to be practically resistant to direct photolysis under weak radiant energies available in natural conditions. The estimated reaction efficiencies, in addition to half-lives, speak for that NO ₃ ^? and CDOM do not act as quite independent photoinductors but their effect in conjunction (CDOM?CNO ₃ ^? ?Cwater) is stronger than the separate ones. The principal phototransformation intermediates of APAP were mono-hydroxy derivatives, depending on available photon energies formed via ortho- or meta-hydroxylation, possessing substantial power of resistance to further specific transformation reactions.

Conclusions

The estimated half-life of the phototransformation of APAP in the natural aqueous environment and in the presence of suitable photoinductors will be about 30?days or more.     

Application of central composite face-centered design and response surface methodology for the optimization of electro-Fenton decolorization of Azure B dye

Purpose

The aim of this work was to improve the ability of electro-Fenton technique for the remediation of wastewater contaminated with synthetic dyes using a model azo dye such as Azure B.

Methods

Batch experiments were conducted to study the effects of main parameters, such as dye concentration, electrode surface area, treatment time, and voltage. In this study, central composite face-centered experimental design matrix and response surface methodology were applied to design the experiments and evaluate the interactive effects of the four studied parameters. A total of 30 experimental runs were set, and the kinetic data were analyzed using first- and second-order models.

Results

The experimental data fitted to the empirical second-order model of a suitable degree for the maximum decolorization of Azure B by electro-Fenton treatment. ANOVA analysis showed high coefficient of determination value (R ²?=?0.9835) and reasonable second-order regression prediction. Pareto analysis suggests that the variables, time, and voltage produce the largest effect on the decolorization rate.

Conclusion

Optimum conditions suggested by the second-order polynomial regression model for attaining maximum decolorization were dye concentration 4.83?mg/L, electrode surface area 15?cm², voltage 14.19?V, and treatment time of 34.58?min.     

Microbial structure and chemical components of aerosols caused by rotating brushes in a wastewater treatment plant

Purpose

Bacterial community structure and the chemical components in aerosols caused by rotating brushes in an Orbal oxidation ditch were assessed in a Beijing municipal wastewater treatment plant.

Methods

Air samples were collected at different distances from the aerosol-generating rotating brushes. Molecular culture-independent methods were used to characterize the community structure of the airborne bacteria in each sample regardless of cell culturability. A clone library of 16S rDNA directly amplified from air DNA of each sample was constructed and sequenced to analyze the community composition and diversity. Insoluble particles and water-soluble ions emitted with microorganisms in aerosols were analysis by a scanning electron microscope together with energy dispersive X-ray spectroscopy and ion chromatogram analyzer.

Results

In total, most of the identified bacteria were Proteobacteria. The majority of sequences near the rotating brushes (the main source of the bioaerosols) were Proteobacteria (62.97 %) with ??-(18.52 %) and ??-(44.45?%) subgroups and Bacteroidetes (29.63 %). Complex patterns were observed for each sampling location, suggesting a highly diverse community structure, comparable to that found in water in the Orbal oxidation ditch. Accompany with microorganisms, 46.36???g/m³ of SO ₄ ^2? , 29.35???g/m³ of Cl^?, 21.51???g/m³ of NO ₃ ^? , 19.76???g/m³ of NH ₄ ⁺ , 11.42???g/m³ of PO ₄ ^3? , 6.18???g/m³ of NO ₂ ^? , and elements of Mg, Cl, K, Na, Fe, S, and P were detected from the air near the aerosols source.

Conclusions

Differences in the structure of the bacterial communities and chemical components in the aerosols observed between sampling sites indicated important site-related variability. The composition of microorganisms in water was one of the most important sources of bacterial communities in bioaerosols. Chemical components in bioaerosols may provide a media for airborne microorganism attachment, as well as a suitable microenvironment for their growth and survival in the air. This study will be benefit for the formulation of pollution standards, especially for aerosols, that take into account plant workers?? health.     

Characteristics of precipitation chemistry at Lushan Mountain, East China: 1992–2009

Introduction

Trends in precipitation pH and conductivity during 1992?C2009, and in ionic compositions from January 2007 to June 2009, are reported from Lushan Mountain, one of the highest mountains in mid-east China. Annual mean pH was in the range of 4.35?C5.01 and showed a statistically very significant (P?P?Results and discussions Over the period of study, Lushan Mountain received more rainfall in spring and summer. The pH values varied seasonally with winter minima. The winter multiyear seasonal mean pH was 4.35. The corresponding summer value was 4.88. SO ₄ ^2? and NO ₃ ^? were the main anions, and NH ₄ ⁺ and Ca²⁺ the main cations. The anion to cation ratio was 0.8?C1.0, and that of [SO ₄ ^2? ] to [NO ₃ ^? ] was 2.4-3.0, much lower than that of the 1980s. However, sulfuric acid was still the main acid present. The ratio of [NH ₄ ⁺ ] to [Ca²⁺] was about 1.0, suggesting that these two alkaline substances provided close acid neutralizing capacity. The ratio of [Cl^?] to [Na⁺] was about 0.67, somewhat lower than that of natural precipitation.

Conclusions

Ionic composition varied seasonally and was closely correlated to the amounts of rainfall and pollution. Trajectory analyses showed that the trajectories to Lushan Mountain could be classified in six clusters and trajectories originating from the South Sea and the areas surrounding Lushan Mountain had the greatest impacts on precipitation chemistry.     

Degradation and mineralization of sulcotrione and mesotrione in aqueous medium by the electro-Fenton process: a kinetic study

Introduction

The degradation and mineralization of two triketone (TRK) herbicides, including sulcotrione and mesotrione, by the electro-Fenton process (electro-Fenton using Pt anode (EF-Pt), electro-Fenton with BDD anode (EF-BDD) and anodic oxidation with BDD anode) were investigated in acidic aqueous medium.

Methods

The reactivity of both herbicides toward hydroxyl radicals was found to depend on the electron-withdrawing effect of the aromatic chlorine or nitro substituents. The degradation of sulcotrione and mesotrione obeyed apparent first-order reaction kinetics, and their absolute rate constants with hydroxyl radicals at pH?3.0 were determined by the competitive kinetics method.

Results and discussion

The hydroxylation absolute rate constant (k _abs) values of both TRK herbicides ranged from 8.20?×?10⁸ (sulcotrione) to 1.01?×?10⁹ (mesotrione) L?mol^?1?s^?1, whereas those of the TRK main cyclic or aromatic by-products, namely cyclohexane 1,3-dione , (2-chloro-4-methylsulphonyl) benzoic acid and 4-(methylsulphonyl)-2-nitrobenzoic acid, comprised between 5.90?×?10⁸ and 3.29?×?10⁹?L?mol^?1?s^?1. The efficiency of mineralization of aqueous solutions of both TRK herbicides was evaluated in terms of total organic carbon removal. Mineralization yields of about 97?C98% were reached in optimal conditions for a 6-h electro-Fenton treatment time.

Conclusions

The mineralization process steps involved the oxidative opening of the aromatic or cyclic TRK by-products, leading to the formation of short-chain carboxylic acids, and, then, of carbon dioxide and inorganic ions.