Fate Of Tetracycline Research Articles

Impacts of draw solutes on the fate of tetracycline in an osmotic membrane bioreactor: Role of the combination between membrane fouling and microorganisms

Osmotic membrane bioreactors (OMBRs) are considered a suitable technology for treating wastewater containing tetracycline due to their high rejection and biodegradation efficiency. However, the impact of membrane fouling layer (i.e., chemical composition, microbial composition, and formation) on the filtration and biodegradation of tetracycline is still unclear. Herein, the effects of draw solute concentration and type on the formation of a membrane fouling layer for tetracycline filtration and its relationship with microbial activity were investigated. The results showed that over 99% of tetracycline was retained on the feed side by membrane rejection, and the fouling layer played an important role in tetracycline filtration. Specifically, membrane foulants resulted in a more hydrophilic membrane facilitating tetracycline filtration, while the tetracycline-degrading genera from the fouled membrane promoted tetracycline degradation. The structure equation model showed that tetracycline filtration dominated by electrostatic repulsion between tetracycline and the fouled membrane was more important than tetracycline degradation for tetracycline removal (path coefficient of 0.655 vs. 0.395). This study provided insights into the combined effect of membrane foulants and microorganisms on tetracycline removal.

Removal of tetracycline in nitrification membrane bioreactors with different ammonia loading rates: Performance, metabolic pathway, and key contributors

Membrane bioreactors (MBRs) have been widely applied for the treatment of wastewater that contains high concentrations of both ammonium and antibiotics. Nonetheless, information about tetracycline (TC) removal in nitrification MBRs with high ammonium loading rates (ALRs) is still very limited. Herein, the fate of TC at four different concentrations of 1, 5, 20, and 50 mg/L in three parallel lab-scale nitrification MBRs with different ALRs (named AN50, AN500, and AN1000) were investigated in this study. Excellent nitrification performance and high TC removal efficiency (90.46%) were achieved in AN1000 at influent TC concentration of 50 mg/L. Higher ALRs promoted the removal of TC at lower influent TC concentration (≤5 mg/L), while no significant difference was observed in TC removal efficiencies among different ALRs MBRs at higher influent TC concentration (≥20 mg/L), implying that the heterotrophic degradation could be strengthened after long-term exposure to high concentration of TC. Batch tests demonstrated that adsorption and biodegradation were the primary TC removal routes by nitrification sludge, of which both autotrophic ammonia oxidizers and heterotrophic microorganisms played an important role in the biodegradation of TC. FT-IR spectroscopy confirmed that amide groups on the sludge biomass contributed to the adsorption of TC. Mass balance analyses indicated that biodegradation (63.4–88.6% for AN50, 74.5–88.4% for AN500 and 74.4–91.4% for AN1000) was the major mechanism responsible for the removal of TC in nitrification MBRs, and its contribution increased with influent TC concentration, while only 1.1%–15.0% of TC removal was due to biosorption. TC was progressively degraded to small molecules and the presence of TC had no notable effect on membrane permeability. These jointly confirmed TC could be effectively removed via initial adsorption and subsequent biodegradation, while biodegradation was the primary mechanism in this study.

Shedding light on the transfer of tetracycline in forward osmosis through experimental investigation and machine learning modeling

Tetracycline in wastewater can pose adverse impacts on the environment and human health. Forward osmosis (FO) is a promising method to reject antibiotics due to its low energy demand and high rejection rate. Tetracycline rejection during FO is a complicated process. Mechanistic models have been developed to describe antibiotic rejection by the FO membrane under ideal conditions but cannot be applied to real wastewater. Herein, the effects of draw concentration, pH, and solute type on the fate of tetracycline during FO were investigated by combining experimentation, factor analysis, and artificial neural network (ANN) modeling. High draw concentrations led to high convection that favored tetracycline diffusion. Low draw pH helped reject antibiotics potentially due to the decreased tortuosity and pore size of the FO membrane. When different draw solutes were tested, both convection and electrostatic interaction exerted effects on tetracycline retention on the FO membrane surface, and steric hindrance could further affect the amount of tetracycline in the draw solution. Exploratory factor analysis (EFA) showed that tetracycline rejection was a combined result of convection, steric hindrance, and electrostatic interactions. Path analysis revealed the significant roles of initial conductivity and draw pH in tetracycline rejection. Eight representative input variables were selected from 13 observed explanatory variables using redundancy analysis (RDA), based on which an ANN was trained and successfully predicted tetracycline diffusion and transfer through the FO membrane. These results have provided practical and predictive insights in the development of FO processes for efficient treatment of pharmaceutical wastewater.

The fate of tetracycline in vegetated mesocosmic wetlands and its impact on the water quality and epiphytic microbes

The fate of antibiotics and their impact on antibiotic resistance genes (ARGs) and microbial communities are far from clear in wetlands. The fate and impact of tetracycline (TC) on the nutrient degradation of wetlands and epiphytic microbes were investigated. This study showed that after TC spiking, 99.7% of TC were removed from the surface water of wetlands containing Vallisneria spiralis within 4 days post-treatment. TC spiking impaired the nutrient removal capacity and disrupted epiphytic microbial community structure while enhancing the abundance of 11 ARGs subtypes, including tetracycline resistance genes, tetX, tetM, tetO, tetQ, tetS, and tet36. TC decreased bacterial biodiversity but amplified the relative abundance of Proteobacteria and Firmicutes by 4% and 61%, respectively, and increased eukaryotic diversity. 16 metabolic pathways including Carbohydrate, Energy, Amino acid, ‘cofactor and vitamins’ metabolisms were significantly (p < 0.01) increased in TC treatment. Phylogenetic, functional prediction analysis indicated that Flavobacterium was positively related with xenobiotics, cell motility, ‘terpenoids and polyketides’ metabolism but negatively related to nucleotide metabolism, while Rhodobacter showed a reverse trend but positively related with nucleotide and ‘glycan biosynthesis’ and metabolism. These data highlighted that TC has negative impacts on epiphytic microbial community and nutrients removal in wetlands.

Investigation of the deprotonation of tetracycline using differential absorbance spectra: A comparative experimental and DFT/TD-DFT study

Tetracycline is a type of broad-spectrum, naturally occurring antibiotic that leads to several side effects, such as affecting intestinal flora and increase in bacterial resistance. The affinity of tetracycline for abiotic and biotic surfaces and metal ions is closely related to its deprotonation state and charge distribution; however, its deprotonation-protonation property remains unclear. In this study, the hydrolysis of tetracycline was investigated by combining experiments with quantum-chemical calculations. The molecular structure of the probable deprotonation states were optimized by quantum-chemical calculations, and the corresponding absorbance spectra were predicted based on frontier molecular orbital (FMO) theory. The absorbance spectra showed structure-specific features at the different deprotonation states. In addition, changes in tetracycline absorbance spectra in the pH range of 2.00–12.00 was examined by spectroscopic titration. The deprotonation was found to proceed in the order of site 3, 4, 12, and 10, which was identified by comparing the quantum-chemical calculations and experimental differential absorbance spectra (DAS). The results in this study are of great significance for further studies of the transport and fate of tetracycline in the environment.

Photolysis mechanisms of tetracycline under UV irradiation in simulated aquatic environment surrounding limestone.

As the most typical geological environment, limestone landforms are widespreading in the world and affect the waters that flow around them, which may also change the fate of organic contaminants in these waters. In this study, aquatic environment surrounding limestone was simulated with calcium carbonate, and the photolysis of tetracycline was evaluated under UV irradiation (30μW/cm2). More tetracycline (up to 98%) was removed in 4h in the presence of calcium carbonate while only 50% of tetracycline was eliminated in control experiment. The removal of tetracycline was greatly enhanced due to the major roles of alkaline pH and minor roles of Ca2+ and HCO3-/CO32-. In alkaline pH, tetracycline existed as TCs- with higher electronic density in the ring structures, which was more easily attacked by OH. Besides, it could also change the bond orbital energy to facilitate tetracycline absorbing more photon. Moreover, alkaline pH was beneficial to generate more OH and thus promote the indirect photolysis. In addition, alkaline pH also changed the degradation path of tetracycline and rapidly convert tetracycline to the byproducts with m/z 457 via hydroxylation and hydrogen abstraction. This work provides not only better understanding about the fate of tetracycline in aquatic environments but also new insights into the treatment of antibiotic-contaminated water.

Effects of rainfall events on behavior of tetracycline antibiotics in a receiving river: Seasonal differences in dominant processes and mechanisms.

Tetracycline (TC) antibiotics are widely used in livestock and poultry breeding. However, limited work has been done on the partition of TCs between suspended sediment (SPS) and overlying water or on the seasonal effects of rainfall events on the behavior of TCs in receiving rivers. Here, we assessed the impacts of rainfall events in different seasons on the concentrations and fate of TCs in a typical watershed. Concentrations of TCs in river water, SPS, and surface sediment were determined before, during, and after rainfall events. Results indicated that the sequence of TC concentration levels in river water was wet season > normal season > dry season. Rainfall events in all seasons increased the concentrations of TCs in river water. The concentration of TCs in SPS reached 104 ng/g. The SPS concentrations were only 22-78 mg/L, while the daily fluxes of TCs in particulate form contributed 39%-62% of the total (dissolved and particulate) daily fluxes in river water. The increases in TCs in river water were mainly attributed to internal release from sediment during rainfall events in the dry season but to external input during rainfall events in the wet season. The degradation products of TCs with higher concentrations and greater toxicity than their parent compounds should be considered in the ecological risk assessment of TCs. This research demonstrated that manure application should not be conducted in the normal season or before rainfall events, especially heavy rainfall.

Abiotic transformation products of tetracycline and chlortetracycline in salt solutions and manure

Tetracyclines belong to the group of the most applied antibiotics in veterinary medicine worldwide. Due to their incomplete absorption and/or metabolism in the animal gut, tetracyclines are frequently detected in manure samples. Within the matrix, an elimination of these compounds has been reported in several studies. However, only little information about potential transformation products of tetracyclines in manure and the environment is available. Therefore, the fate of tetracycline (TC) and chlortetracycline (CTC) was investigated in aqueous solutions and manure. Abiotic incubation of TC in phosphate buffer led to a remarkable red-brown coloring of the solution. Subsequent compound isolation and structure elucidation by MS/MS and NMR techniques revealed the formation of seco-cycline A, a compound formerly described as a fungal biotransformation product of TC. For CTC, two comparable products were identified which were derived from its isomeric form isoCTC. All transformation products showed no antimicrobial activity for concentrations up to 500 mg L−1. When TC and CTC were incubated in cow manure for 7 d, the above mentioned three transformation products were also formed in this complex matrix (up to 5.1 mg kg−1). Manure, soil and leachate samples from Lower Saxony revealed the presence of seco-cycline A in manure and soil, but not in water. To obtain a better insight in the fate of tetracyclines in environmental matrices, future analytical and ecotoxicological studies dealing with this subject should include the analysis especially of seco-cycline A.

Fate of tetracycline and sulfonamide resistance genes in a grassland soil amended with different organic fertilizers

This study provided an assessment of the environmental fate of antibiotic resistance genes (ARGs) in a Scottish grassland field repeatedly treated with different organic fertilizers. The impacts of manure, biosolids and municipal food-derived compost on the relative abundances of tetracycline ARGs (tetA, tetB, tetC, tetG and tetW), sulfonamide ARGs (sul1 and sul2) and class 1 integron-integrase gene (IntI1) in soils were investigated, with inorganic fertilizer (NPK) as a comparison. The background soil with a history of low intensity farming showed a higher total relative abundance of tet ARGs over sul ARGs, with tetracycline efflux genes occurring in a higher frequency. In all treatments, the relative abundances of most ARGs detected in soils decreased over time, especially IntI1 and tet ARGs. This general attenuation of soil ARGs is a reflection of changes in the soil microbial community, which is supported by the result that almost all the soils at the end of the experiment had different bacterial communities from the untreated soil at the beginning of the experiment. Multiple applications of organic fertilizers to some extent counteracted the decreasing trend of soil ARGs relative abundances, which resulted in higher ARGs relative abundances in comparison to NPK, either by a lesser decrease of IntI1 and tet ARGs or an increase of sul ARGs. The enhancement of existing soil ARG prevalence by organic fertilizers was strongly dependent on the organic fertilizer type and the particular ARG. Compost contained the lowest relative abundance of inherent ARGs and had the least effect on the soil ARG decrease after application. The relative increase of tet ARGs caused by biosolids was larger than that of sul ARGs, while manure caused the opposite effect. Fertilization practices did not exert effective impacts on the soil bacterial community, although it caused significant changes in the profile of the ARG pool. Organic fertilization may thus accelerate the dissemination of ARGs in soil mainly through horizontal gene transfer (HGT), consistent with the enrichment of IntI1 in organic fertilized soils.

Effects of earthworms on the fate of tetracycline and fluoroquinolone resistance genes of sewage sludge during vermicomposting

Diverse antibiotic resistance genes (ARGs) present in sewage sludge are difficult to be eliminated using conventional sludge treatment processes. To date, little remains known on the fate of the ARGs during vermicomposting of sludge. This study aimed to investigate the effect of earthworms on the fate of tetracycline and fluoroquinolone resistance genes, and integrons during vermicomposting of sewage sludge through contrasting two systems of sludge stabilization with and without earthworms. Compared to the control without earthworms, vermicomposting significantly (p < 0.05) decreased the abundances of tetracycline and fluoroquinolone resistance genes and int1, with complete removal for parC. Variations in ARGs were associated with environmental factors, horizontal gene transfer, bacterial community composition, and earthworms during vermicomposting. In addition, earthworms strongly affected the possible host bacteria encoding ARGs and Int1, abating the pathogenic bacteria in vermicomposting product. These results imply that vermicomposting could effectively reduce tetracycline and fluoroquinolone resistance genes in the sludge.

Fate of tetracycline in enhanced biological nutrient removal process

This study investigated the fate of tetracycline at four different concentrations of 20 μg L−1, 50 μg L−1, 2 and 5 mg L−1 in the enhanced biological nutrient removal processes. At the tetracycline concentration below 50 μg L−1, no obvious inhibition on the biological N&P removal was observed, while the inhibition appeared after the tetracycline concentration was increased to 2 and 5 mg L−1. It was found that about 44%–87% of tetracycline was removed through biodegradation, while only 3%–6% of removal was due to biosorption. These results clearly suggested that a substantial amount of tetracycline eventually ended up in sludge with the tetracycline content of 23 mg to 4.5 g kg−1 sludge depending on the tetracycline concentration. Obviously, this could pose an emerging challenge to the post sludge disposal and reuse. Furthermore, phthalic anhydride was detected as a biodegradation byproduct of tetracycline, which has been known to be more toxic than tetracycline to aquatic organisms. Consequently, this study offers in-depth insights into the fate of tetracycline in the enhanced biological nutrient removal process, highlighting on the emerging ecological risks associated with sludge disposal and effluent discharge.

Fate of tetracycline and sulfamethoxazole and their corresponding resistance genes in microbial fuel cell coupled constructed wetlands

CW-MFC could significantly reduce the concentrations of TC and SMX in wastewater.

Fate of tetracycline at high concentrations in enriched mixed culture system: biodegradation and behavior

Fate of tetracycline at high concentrations in enriched mixed culture system: biodegradation and behavior

The occurrence and fate of tetracyclines in two pharmaceutical wastewater treatment plants of Northern China.

Several parameters of the method, solid-phase extraction (SPE)-ultra-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS), were optimized to investigate the presence and partitioning of 18 antibiotics (including sulfonamides, tetracyclines, quinolones, macrolides, and β-lactams) during various processing stages at two typical pharmaceutical wastewater treatment plants (PWWTPs) in northern China. Oxytetracycline (OTC), chlortetracycline (CTC), and tetracycline (TC) were all detected in each stage of both PWWTPs. Antibiotics were largely removed through biological units of both PWWTPs, with removal efficiencies of 62.0 to 78.3%. Mass balance analyses indicated that degradation (44.8-53.7% for PWWTP1 and 40.1-59.6% for PWWTP2) was the major mechanism responsible for the removal of tetracyclines, whereas the contribution of sorption by sludge (12.6-20.0% for PWWTP1 and 18.7-33.5% for PWWTP2) was less significant for the investigated pharmaceuticals. Although there was significant removal of tetracyclines through PWWTPs, large amounts of tetracyclines were still discharged through the effluent (up to 32.0 ± 6.0 mg L(-1)) and dewatered sludge (up to 5,481.1 ± 123.0 mg kg(-1)), which increased the risk of selecting for antibiotic resistance in the receiving water and soil environments.

Uptake of tetracycline and metabolites in Phragmites australis exposed to treated poultry slaughterhouse wastewaters

Abstract In this study, the uptake of tetracycline (TC) and metabolites (ETC, EATC and ATC) by Phragmites australis naturally grown in a stream (Hinsor stream, Turkey) that takes the treated wastewaters of a poultry slaughterhouse was investigated. Furthermore, the occurrence and fate of TC and metabolites were also investigated in the stream. The decreasing uptake order of TC and metabolites by P. australis was root > stem > leaf. The determined concentrations of TC and metabolites in roots and stems were followed the decreasing order of EATC > ATC> ETC> TC. The uptake order of TC and metabolites in leaves was ATC > EATC > ETC > TC. The highest TC, ETC, EATC and ATC concentrations in surface water (SW) samples were obtained as 2.37 ± 0.11, 3.96 ± 0.19, 21.3 ± 1.0 and 11.2 ± 0.5 μg/L, respectively. The highest TC, ETC, EATC and ATC concentrations in sediment samples were obtained as 9.69 ± 0.48, 27.0 ± 1.3, 13.9 ± 0.69 and 23.0 ± 1.11 ppb, respectively.

Fate of tetracycline, sulfonamide and fluoroquinolone resistance genes and the changes in bacterial diversity during composting of swine manure

This study monitored the abundance of antibiotic resistant genes (ARGs) and the bacterial diversity during composting of swine manure spiked with chlortetracycline, sulfadiazine and ciprofloxacin at two different levels and a control without antibiotics. Resistance genes of tetracycline (tetQ, tetW, tetC, tetG, tetZ and tetY), sulfonamide (sul1, sul2, dfrA1 and dfrA7) and fluoroquinolone (gyrA and parC) represented 0.02–1.91%, 0.67–10.28% and 0.00005–0.0002%, respectively, of the total 16S rDNA copies in the initial composting mass. After 28–42days of composting, these ARGs, except parC, were undetectable in the composting mass indicating that composting is a potential method of manure management. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis of bacterial 16S rDNA of the composting mass indicated that the addition of antibiotics up to 100, 20 and 20mg/kg of chlortetracycline, sulfadiazine and ciprofloxacin, respectively, elicited only a transient perturbation and the bacterial diversity was restored in due course of composting.

Transformation of Tetracyclines Mediated by Mn(II) and Cu(II) Ions in the Presence of Oxygen

Complexation of tetracyclines (TCs) with dissolved Mn(II) and Cu(II) ions were found to significantly enhance the transformation of these antibiotics in the presence of oxygen at pH 8-9.5 and pH 4-6, respectively. In the TC-Mn(II)-O2 system, oxidation of the TC-complexed Mn(II) to Mn(III) by oxygen occurs, followed by oxidation of TC by Mn(III) to regenerate Mn(II). In the TC-Cu(II)-O2 system, Cu(II) oxidizes TC within the complex and the yielded Cu(I) is reoxidized by the present oxygen. Opposite reactivity trends were observed with the two metals: OTC (oxytetracycline) > TTC (tetracycline) >> iso-CTC (iso-chlorotetracycline) for the Mn(II)-mediated reaction, whereas CTC > TTC > OTC > epimers for the Cu(II)-mediated reaction. The reactivity results and examination of TC-metal ion complexation and transformation products suggest that the BCD-ring and A-ring of TC are crucial to interact with Mn(II) and Cu(II), respectively. This study highlights that the fate of TCs in aquatic environments may differ significantly by their strong interactions with different metal species present in the systems.

Analysis of tetracycline antibiotics in soil: Advances in extraction, clean-up, and quantification

Residues of tetracyclines end up in the environment due to the common practice of land application of manure from treated animals. The environmental behavior and the fate of tetracyclines in manure and soil after cropland application remain largely unknown. The lack of information on the nature of the biodegradation products of tetracyclines formed at environmentally-relevant concentrations is mostly due to analytical difficulties encountered when trying to analyze trace levels of these compounds in the presence of complex matrices. Liquid chromatography coupled to mass spectrometry (LC-MS) has become widely used in detecting polar pollutants such as antibiotics. In applying LC-MS for environmental investigations, the analyst is faced with two major challenges: poor detectability of analytes; and, highly variable matrix interferences that compromise quantification. To improve our understanding of the fate and effects of tetracycline antibiotics in the environment, improved methods for detection, quantification, and unknown identification are needed. In this review, we discuss strategies for sample preparation, extraction, clean-up using solid-phase extraction (SPE) and molecularly-imprinted polymers (MIPs), and analysis of tetracyclines and their transformation products in soil, in order to facilitate future environmental fate studies, and to challenge analytical chemists to develop the necessary tools to allow a complete risk assessment of other pharmaceutical contaminants in the environment.

Behaviour and fate of tetracycline in river and wetland waters on the Canadian Northern Great Plains

Very little is known about the factors affecting the behaviour, degradation and persistence of tetracycline in sensitive Prairie freshwater aquatic systems in Canada. Reported are results of studies conducted for the first time of tetracycline behaviour in Prairie river and wetland waters. For comparison, studies were also conducted using distilled water as a control. Different amounts of spiked tetracycline (0, 50 and 80 percent) was adsorbed by distilled, river and wetland water, respectively. These different amounts are likely due to the differences in the matrixes of the three waters. In wetland water, the addition of EDTA generally promoted the release of tetracycline indicating that a portion of the tetracycline was bound to metal ions. Decreasing the pH of the wetland water led to increased adsorption of tetracycline suggesting either that tetracycline epimerizes or binds, by hydrogen bonding, to acidic portions of organic material in the water. However, in wetland water, a significant portion of the spiked tetracycline (≅ 50%) was irreversibly bound to the water matrix and was not released by adding EDTA and/or by varying the pH. In laboratory experiments, the t1/2 of “free-form” tetracycline exposed to light (L+) in non-sterile waters was 32, 2 and 3 days in distilled, river and wetland water respectively, while in waters with no light exposure (L−), they were 83, 18 and 13 days. Similarly, t1/2 of tetracycline in L+ sterile waters treatments was 9, 1 and 1 day for distilled, river and wetland water, respectively, and 18, 11 and 7 days in the L−. In the experiment conducted in natural sunlight, tetracycline t1/2 in the presence of ultraviolet radiation (UV) treatments was 26, 17 and 18 min in distilled, river and wetland water and 39, 28 and 32 min in the absence of UV treatment. The combination of the effects of matrixes of the water, light and UV radiation therefore play a significant role in catalyzing the removal of tetracycline from different Prairie waters. In deep waters and in systems where sunlight is highly attenuated, the effects of light on tetracycline may be considerably reduced.

Research Advances: Eating Clay?; Look to Soil for New Leads in Arthritis Treatment; The Fate of Tetracyclines

This look at recent research advances in the literature discusses understanding the link between geology and health; the search for new arthritis medications.; and the sorption of tetracyclines.