Antibiotic Pollution Research Articles

Current Status and Spatiotemporal Evolution of Antibiotic Residues in Livestock and Poultry Manure in China

The use of antibiotics in the livestock and poultry industries has raised significant concern about environmental and health problems. In light of this, accurate knowledge of antibiotic residues in livestock and poultry manure is important for pollution management and strategic decision-making at the national level. This study aims to provide a comprehensive report on antibiotic residues in livestock and poultry manure in China using the published data of 3751 livestock and poultry feces in 29 provincial-level units over the past 20 years. In this study, the overall status of antibiotic residues in livestock and poultry feces was analyzed by mathematical statistics. Moreover, the spatio-temporal variation characteristics were analyzed by spatial statistics, and the differences among livestock and poultry species were evaluated by subgroup analysis. The finding indicated that tetracyclines (TCs), quinolones (QLs), sulfonamides (SAs), and macrolides (MLs) were the most abundant residues in livestock and poultry manure. The spatial and temporal variation revealed that the overall trend of antibiotic residues decreased gradually, and the spatial distribution was primarily concentrated in the southeast of Hu Line, exhibiting a “northeast-southwest” distribution. The distribution range also decreased slightly, with the residues of tetracyclines (TCs), quinolones (QLs), sulfonamides (SAs), and pleuromutilins (PMs) showing a significant spatial hot spot. The center of gravity of antibiotic residue shifted to the southwest between 2003 and 2021. In comparison to cow and sheep manure, the tetracyclines (TCs), sulfonamides (SAs), and macrolides (MLs) in pig and chicken manure were higher. The results can serve as a reference for the control and reduction of antibiotic pollution in livestock and poultry manure, as well as the wise utilization of those resources and achieving goals for clean agriculture.

Sulfur vacancies promoted highly efficient visible light photocatalytic degradation of antibiotic and phenolic pollutants over WS2/rGO heterostructure

Antibiotic and phenolic contaminations are severe and have become a significant source of worry in recent years. A multifunctional sulfur vacancy-induced WS2/rGO heterostructure was fabricated by a simple hydrothermal process for the photocatalytic degradation of antibiotic and phenolic compounds. The sulfur-based defects can reduce bandgap energies and enhance visible light absorption. The sulfur-enriched WS2/rGO heterostructure exhibited efficient photocatalytic activity towards Ciprofloxacin (CIP) and 4-Nitrophenol (4-NP) degradation under visible light illumination, and the deceptive rate constant is about 13 and 22 times higher than pristine WS2, and the removal efficiency was 16 and 13 times higher than pristine GO catalysts. The degradation efficiency and kinetic rate constants of 4-NP and CIP were 96.95 %, 92.30 %, and 0.113 min−1, 0.027 min−1, respectively. The excellent photocatalytic activity of WS2/rGO heterostructure was due to rGO acts as an electron mediator, and helps to accelerate charge separation and reduce the recombination rates. In addition, rGO improved the surface appearance of the heterostructure and provided more adsorption and reaction sites. The photocurrent measurement and time-resolved spectrum were used to investigate the photogenerated charge separation. Furthermore, the superoxide radical was the dominant reactive species of 4-NP and CIP degradation, as demonstrated by electron spin resonance and scavenger experiments. The possible degradation pathway and mechanism of 4-NP were proposed using liquid chromatography-mass spectroscopy.

Microbial community and gene dynamics response to high concentrations of gadolinium and sulfamethoxazole in biological nitrogen removal system

The impact of high antibiotic and heavy metal pollution levels on biological nitrogen removal in wastewater treatment plants (WWTPs) remains poorly understood, posing a global concern regarding the issue spread of antibiotic resistance induced by these contaminants. Herein, we investigated the effects of gadolinium (Gd) and sulfamethoxazole (SMX), commonly found in medical wastewater, on biological nitrogen removal systems and microbial characteristics, and the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and mobile genetic elements (MGEs). Our findings indicated that high SMX and Gd(III) concentrations adversely affected nitrification and denitrification, with Gd(III) exerting a strong inhibitory effect on microbial activity. Metagenomic analysis revealed that high SMX and Gd(III) concentrations could reduce microbial diversity, with Thauera and Pseudomonas emerging as dominant genera across all samples. While the relative abundance of most ARGs decreased under single Gd(III) stress, MRGs increased, and nitrification functional genes were inhibited. Conversely, combined SMX and Gd(III) pollution increased the relative abundance of intl1. Correlation analysis revealed that most genera could host ARGs and MRGs, indicating co-selection and competition between these resistance genes. However, most denitrifying functional genes exhibited a positive correlation with MRGs. Overall, our study provides novel insights into the impact of high concentrations of antibiotics and heavy metal pollution in WWTPs, and laying the groundwork for the spread and proliferation of resistance genes under combined SMX and Gd pollution.

A co-precipitation synthesized BiOI/(BiO)2CO3 nanocatalyst: An experimental design and mechanism study towards photodegradation of sulfasalazine

BackgroundIncreased antibiotic consumption residues a large amount of antibiotics in the bacterial communities and ecosystems, leading to bacterial persistence against them. Thus, in recent decades, an urgent need has been to introduce/develop novel catalysts/adsorbents/methods to diminish the pollution extent of the aquatic environment by various organic pollutants like antibiotics. MethodsBiOI/(BiO)2CO3 was synthesized by adding ammonium iodide to the aqueous suspension of (BiO)2CO3 (BOC) under hydrothermal conditions. The individual BiOI and (BiO)2CO3 and their p-n heterojunction system were characterized by some identification techniques like UV–vis diffuse reflectance spectroscopy (DRS) and electrochemical impedance spectroscopy (EIS). Significant findingsThe direct band gap energies of 1.99, 3.54, and 2.42 eV were obtained for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 samples from the Tauc plots. Both CVs and EIS results confirmed better charge transfer in the coupled catalyst. pHpzc for BiOI, (BiO)2CO3 and BiOI/(BiO)2CO3 was 6.3, 10.1, and 6.5. The response surface methodology (RSM) approach was used to construct a design model to investigate the interaction effects of the most influencing variables on the boosted catalytic effect of the coupled catalyst toward sulfasalazine (SSZ) as a model antibiotic pollutant. The model goodness was confirmed based on model F-value=20.59 > F0.05, 14, 13 = 2.55 and lake of fit (LOF) F-value = 0.364 < F0.05, 10, 3 = 8.73, as well as by adequate regression coefficient (R2) of 0.9705, adjusted R2 (0.9699), and predicted R2 (0.9575) values. RSM optimal run included pH 6.0, catalyst dose: 0.55 g/L, irradiation time: 50 min, and SSZ concentration of 6 ppm, which resulted in a 95.3 % photodegradation efficiency. The relative role of photoinduced holes> photoinduced electrons > hydroxyl radicals> superoxide radicals was obtained in the photodegradation efficiency by the results obtained in the presence of some scavenging species. Accordingly, the photodegradation pathway was suggested. We believe simple preparation of the BiOI/(BiO)2CO3 photocatalyst via a co-precipitation anion-exchanged consisted procedure by adding iodide anion to the aqueous suspension of (BiO)2CO3 is an advantage of this work.

Occurrence, distribution, and behaviors of erythromycin A, production byproducts, transformation products, and resistance genes in a full-scale erythromycin A production wastewater treatment system

Antibiotic production wastewater from pharmaceutical manufacturing is a significant source of antibiotic and resistance gene pollution in the environment. Given that Erythromycin A (Ery-A) is a widely used antibiotic in both human clinical and livestock breeding, it is imperative to ascertain its presence, along with related compounds, in the biological treatment processes of production wastewater. In this study, the occurrence and behavior of Ery-A, its production byproducts, transformation products, and resistance genes were first systematically investigated in a full-scale anaerobic-aerobic system for treating Ery-A production wastewater. Simultaneously, residual antibacterial activity in wastewater and sludge was evaluated throughout the wastewater treatment process. Ery-A contributes only 24.2 – 36.0% to the antibacterial activities. Ery-A-derived compounds including production byproducts (erythromycin B and erythromycin C) and transformation products (anhydro erythromycin A, N-demethyl-erythromycin A, and erythromycin A enol ether), are determined to contribute to the antibacterial activities of the wastewater treatment system. High concentrations of antibiotics with antibacterial activity (up to 1,258.9 mg/kg·TS for erythromycin A enol ether) adsorbed in the sludge result in near collapse of the first-stage anaerobic sludge system. Sludge biodegradation in second-stage anaerobic and anoxic-aerobic tanks is essential in removing Ery-A-related compounds from wastewater. The Ery-A-related compounds in the secondary effluent and excess sludge are determined to be 44.5 g/h and 1.5 g/h through the mass balance analysis, respectively. The discharge of MLS resistance genes from the secondary effluent and excess sludge is 1.0 × 1016 copies/h and 7.1 × 1015 copies/h, respectively. These findings highlight the significant concern over the release of Ery-A-related compounds and MLS resistance genes from the Ery-A production wastewater treatment system. As a result, it is crucial to implement strategies for the removal of Ery-A-related compounds from production wastewater before biological processes. This study is the first to report the occurrence and behavior of Ery-A-related compounds and resistance genes along the full-scale wastewater treatment processes. Additionally, it sheds light on the importance of byproducts and transformation products with antibacterial activity from Ery-A in the Ery-A production wastewater treatment system.

Adsorption of levofloxacin by ultraviolet aging microplastics

Microplastics can combine with pollutants such as antibiotics and pose a threat to the environment and organisms. At the same time, the inevitable aging behavior of microplastics in the actual environment leads to changes in their physical and chemical properties, and thus changes the reaction mechanism between microplastics and other pollutants. In this study, we used three common microplastics PE/PS/PA to study the adsorption behavior of levofloxacin hydrochloride. Ultraviolet aging method was used to simulate the aging process of levofloxacin hydrochloride under sunlight, and compared with that of before aging. The results showed that the order of adsorption capacity was PS-UV > PA-UV > PE-UV > PA > PS > PE. Aging behavior can significantly enhance the adsorption capacity of microplastics to pollutants. Both Langmuir and Freundlich models can be used to fit the isothermal adsorption process well, indicating that the adsorption process was not a simple monolayer adsorption, but also a multi-molecular layer adsorption. The experiments showed that the adsorption process was affected by various mechanisms, including π-π conjugation, hydrogen bond, ion exchange and electrostatic interaction. This study elucidated the interaction mechanism between microplastics and levofloxacin hydrochloride, which has important significance for future control of microplastics and antibiotic pollution.

Red mud-based heterogeneous catalyst for hydrothermal resource-based degradation of norfloxacin in pharmaceutical wastewater by hydrogen peroxide

Red mud (RM) was used as a catalyst for the hydrothermal degradation of antibiotics in simulated pharmaceutical wastewater by H2O2 to produce formic acid. Formic acid could be adopted as hydrogen storage, conforming to carbon neutral strategy. When 10 mL norfloxacin (NOR) solution was used at 40 mg/L, the optimal reaction conditions were 0.02 g RM activated at 100 °C, 0.2 mL added H2O2, as well as the reaction time and temperature of 0.5 h and 90 °C, leading to NOR degradation rate of 69.26 % and a formic acid yield of 58.36 % (selectivity: 87.56 %). The RM catalyst presented good activity and stability in reuse. In this study, phase composition and structure of RM catalyst before and after the reaction were comprehensively characterized, and kinetic model was established. Moreover, the key intermediate pathway of NOR degradation was identified by LC-MS. Under the concept of “treating waste with waste”, these results suggested that wastewater-treatment technology of solid waste (Red Mud) was “Fenton-like” catalyst for resource-based degrading high-ecotoxicity antibiotic pollutants in pharmaceutical wastewater. This process could support environmental protection and green development of the pharmaceutical industry, together with hazardous waste-recycling treatment. In short, this research provides a theoretical basis for the subsequent engineering resource treatment of pharmaceutical wastewater.

Source Apportionment and Source-specific Risk of Typical Antibiotics in Baiyangdian Lake

The current situation of antibiotic pollution in lakes is critical. At present, most of the previous studies on antibiotics in lakes have focused on the spatiotemporal distribution and risk assessment, while less attention has been paid to the source apportionment. Ultra-high performance liquid chromatography-mass spectrometry was used to determine the concentration of tetracyclines (TCs), sulfonamides (SAs), and quinolones (QNs) in the samples. The source apportionment and source-specific risk of typical antibiotics in the study area were analyzed using the combination of a PMF model and risk quotients (RQ). The results showed that ① the total concentrations of target antibiotics (Σ antibiotics) ranged from ND to 2635 ng·L-1 for surface water and from ND to 259.8 ng·g-1 for sediments. ② The spatial distribution of QNs in surface water decreased from west to east, SAs decreased from middle to north and south, and TCs increased from middle to north and south. In the sediment, QNs decreased from middle to east and west, whereas SAs and TCs increased from east to west. ③ Aquaculture was the major antibiotic source, accounting for the highest proportion (33.2%), followed by sewage treatment plants (29.2%), livestock activities (18.9%), and domestic sewage (18.7%). ④ The ecological risk assessment results showed that enrofloxacin and flumequine were at a medium-high risk level. ⑤ For the spatial distribution of source-specific risk, the results showed that the aquaculture at S1 was at a high risk level, whereas the source-specific risks for other sites were at a medium-low risk level. In terms of source types, aquaculture was at a medium-high risk level, whereas the other sources were at a medium-low risk level. Therefore, considering the major sources and source-specific risk level of antibiotics, more precise and scientific antibiotic risk control should be adopted in Baiyangdian Lake.

Spatial-temporal Changes and Driving Factors of Soil Microbial Communities in a Typical City of North China Plain

The structure and function of microbial communities are affected by several environmental factors. To clarify the spatial-temporal changes and main influencing factors of soil microbial communities in a typical pharmaceutical city, it is urgent to study the spatial-temporal changes in microbial communities in soils for typical cities. Shijiazhuang City was selected as the study area, and 12 sampling sites were selected. The topsoil was collected in June (summer) and September (autumn) of 2021. The 16S rRNA high-throughput sequencing technology was used to study the structure and function of microbial communities in the soil and explore their spatial-temporal changes. Concurrently, Pearson correlation analysis was applied to establish the correlation between the microbial community and environmental factors, and identify the main driving factors of temporal and spatial changes in the microbial community. The results showed that:① Actinobaciota and Proteobateria were the main dominant bacteria in the surface soil of Shijiazhuang City; at the phylum level, the relative abundance of Actinobacteria and Proteobateria decreased from summer to autumn; at the genus level, the dominant genera were Arthrobacter and unknown genera in summer and Arthrobacter and Candidatus_Nitrocosmicus in autumn, which showed significant seasonal differences (P<0.05). ② For seasonal variation, the mean values of the Simpson, Ace, and Chao indices increased, whereas the mean values of OTU decreased; for spatial variation, the Shannon and Simpson indices showed significant spatial difference (P<0.01 and P<0.05). ③ There were no significant spatial-temporal differences in various functional genes; thereinto, the relative abundances of energy production and transformation functional genes were the highest (24.06%-24.84% in summer and 24.63%-25.98% in autumn, respectively). ④ The compositions of microbial community, diversity index, and functional genes were significantly correlated with quinolone antibiotics (QNs), total phosphorus (TP), and nitrate nitrogen (NO3--N), most significantly correlated with QNs (|r|>0.900), which indicated that antibiotics were the main driving factor of soil microbial communities. Therefore, to ensure the stability of microbial community structure and function in urban soil, the comprehensive management and control of antibiotic pollution in soil should be further strengthened.

Flesh Without Blood: The Public Health Benefits of Lab‐Grown Meat

Synthetic meat made from animal cells will transform how we eat. It will reduce suffering by eliminating the need to raise and slaughter animals. But it will also have big public health benefits if it becomes widely consumed. In this paper, we discuss how “clean meat” can reduce the risks associated with intensive animal farming, including antibiotic resistance, environmental pollution, and zoonotic viral diseases like influenza and coronavirus. Since the most common objection to clean meat is that some people find it “disgusting” or “unnatural,” we explore the psychology of disgust to find possible counter-measures. We argue that the public health benefits of clean meat give us strong moral reasons to promote its development and consumption in a way that the public is likely to support. We end by depicting the change from farmed animals to clean meat as a collective action problem and suggest that social norms rather than coercive laws should be employed to solve the problem.

A fluorescent Zinc-based coordination polymer for sensing antibiotic pollutants

A fluorescent Zinc-based coordination polymer for sensing antibiotic pollutants

Integrons, transposons and IS elements promote diversification of multidrug resistance plasmids and adaptation of their hosts to antibiotic pollutants from pharmaceutical companies.

Plasmids are important vehicles for the dissemination of antibiotic resistance genes (ARGs) among bacteria by conjugation. Here, we determined the complete nucleotide sequences of nine different plasmids previously obtained by exogenous plasmid isolation from river and creek sediments and wastewater from a pharmaceutical company. We identified six IncP/P-1ε plasmids and single members of IncL, IncN and IncFII-like plasmids. Genetic structures of the accessory regions of the IncP/P-1ε plasmids obtained implied that multiple insertions and deletions had occurred, mediated by different transposons and Class 1 integrons with various ARGs. Our study provides compelling evidence that Class 1 integrons, Tn402-like transposons, Tn3-like transposons and/or IS26 played important roles in the acquisition of ARGs across all investigated plasmids. Our plasmid sequencing data provide new insights into how these mobile genetic elements could mediate the acquisition and spread of ARGs in environmental bacteria.

Facile design and fabrication of RP/ZnIn2S4 composite photocatalysts with efficient removal of antibiotics under visible-light irradiation

Efficient photocatalysts with visible light irradiation have a bright future in practical environmental remediation. ZnIn2S4 is a promising environmentally friendly visible-light photocatalyst, due to its appropriate narrow band gap and excellent chemical stability. In this research, the RP/ZnIn2S4 composites with flower spheroidal morphology were synthesized by loading RP onto the surface of ZnIn2S4 via a one-pot hydrothermal process. The experimental results show that the tetracycline (TC) degradation efficiency of RP(1 wt%)/ZnIn2S4 was up to 85.1 %, compared with pure RP, ZnIn2S4, and other series of RP/ZnIn2S4 composites. The optimal degradation conditions were as following: 1 wt% RP modification amount, 30 mg catalyst amount, 30 mg/L initial TC solution concentration, and the initial reaction pH of 7. At the same time, good repeatability and stability of RP(1 wt%)/ZnIn2S4 toward TC removal confirm its potential value for practical applications. In addition, the degradation efficiency of RP(1 wt%)/ZnIn2S4 for rifamycin and ofloxacin under the similar conditions was 80.2 % and 65.3 %, respectively, indicating the universal application of RP/ZnIn2S4 for degradation of different antibiotic pollutants. The possible photocatalytic mechanism was proposed based on the trapping experiment and ESR test. The RP(1 wt%)/ZnIn2S4 composite photocatalytic materials with high efficiency and stability are expected to contribute to the exploration of the environmental protection field.

The genome of Symbiodiniaceae-associated Stutzerimonas frequens CAM01 reveals a broad spectrum of antibiotic resistance genes indicating anthropogenic drift in the Palk Bay coral reef of south-eastern India.

An increase in antibiotic pollution in reef areas will lead to the emergence of antibiotic-resistant bacteria, leading to ecological disturbances in the sensitive coral holobiont. This study provides insights into the genome of antibiotics-resistant Stutzerimonas frequens CAM01, isolated from Favites-associated Symbiodiniaceae of a near-shore polluted reef of Palk Bay, India. The draft genome contains 4.67 Mbp in size with 52 contigs. Further genome analysis revealed the presence of four antibiotic-resistant genes, namely, adeF, rsmA, APH (3")-Ib, and APH (6)-Id that provide resistance by encoding resistance-nodulation-cell division (RND) antibiotic efflux pump and aminoglycoside phosphotransferase. The isolate showed resistance against 73% of the antibiotics tested, concurrent with the predicted AMR genes. Four secondary metabolites, namely Aryl polyene, NRPS-independent-siderophore, terpenes, and ectoine were detected in the isolate, which may play a role in virulence and pathogenicity adaptation in microbes. This study provides key insights into the genome of Stutzerimonas frequens CAM01 and highlights the emergence of antibiotic-resistant bacteria in coral reef ecosystems.

Source apportionment and specific-source-site risk of quinolone antibiotics for effluent-receiving urban rivers and groundwater in a city, China

There is a large surface-groundwater exchange downstream of wastewater treatment plants (WWTPs), and antibiotics upstream may influence sites downstream of rivers. Thus, samples from 9 effluent-receiving urban rivers (ERURs) and 12 groundwater sites were collected in Shijiazhuang City in December 2020 and April 2021. For ERURs, 8 out of 13 target quinolone antibiotics (QNs) were detected, and the total concentration of QNs in December and April were 100.6-4,398 ng/L and 8.02–2,476 ng/L, respectively. For groundwater, all target QNs were detected, and the total QNs concentration was 1.09–23.03 ng/L for December and 4.54–170.3 ng/L for April. The distribution of QNs was dissimilar between ERURs and groundwater. Most QN concentrations were weakly correlated with land use types in the system. The results of a positive matrix factorization model (PMF) indicated four potential sources of QNs in both ERURs and groundwater, and WWTP effluents were the main source of QNs. From December to April, the contribution of WWTP effluents and agricultural emissions increased, while livestock activities decreased. Singular value decomposition (SVD) results showed that the spatial variation of most QNs was mainly contributed by sites downstream (7.09%-88.86%) of ERURs. Then, a new method that combined the results of SVD and PMF was developed for a specific-source-site risk quotient (SRQ), and the SRQ for QNs was at high level, especially for the sites downstream of WWTPs. Regarding temporal variation, the SRQ for WWTP effluents, aquaculture, and agricultural emissions increased. Therefore, in order to control the antibiotic pollution, more attention should be paid to WWTP effluents, aquaculture, and agricultural emission sources for the benefit of sites downstream of WWTPs.

Face-to-face interfacial assembly of a hybrid NiAl-LDH@BiOIO3 photocatalyst for the effective solar-induced abatement of antibiotic and dye pollutants: Insights into surface engineering and S-scheme charge transfer

The development of hybrid catalysts with 2D/2D interfacial contact and step-scheme (S-scheme) charge transfer is crucial for photocatalysis because these catalysts potentially offer more efficient photoexcited charge separation and separated charge carriers with a stronger redox capability. In this study, we strategically developed a novel hybrid NiAl layered double hydroxide (LDH)@BiOIO3 (BOI) photocatalyst with effective S-scheme charge transfer for the efficient solar-induced abatement of aqueous antibiotic and dye pollutants. The in-situ growth of LDH sheets on BOI sheets yielded a hybrid 2D/2D LDH@BOI photocatalyst with favorable face-to-face interfacial contact, which provided a broader platform for photoinduced charge migration and minimizes charge recombination. Furthermore, the S-scheme charge transfer mechanism within the hybrid photocatalyst effectively promoted the separation of the photoinduced charge carriers and preserved their strong redox capability. These beneficial features, in combination with the large specific surface area and enhanced light-harvesting capability, were responsible for the exceptional photocatalytic performance of the optimized hybrid LDH@BOI photocatalyst in terms of the degradation and mineralization of sulfamethoxazole and Congo red dye. Notably, the proposed hybrid photocatalyst outperformed BOI and LDH individually and previously reported state-of-the-art photocatalysts while maintaining its stability over consecutive test cycles, highlighting it as a promising candidate for photocatalytic applications.

Comparison of antibiotic-resistant Escherichia coli and extra-intestinal pathogenic E. coli from main river basins under different levels of the sewer system development

Antimicrobial-resistant Escherichia coli in the aquatic environments is considered a strong indicator of sewage or animal waste contamination and antibiotic pollution. Sewer construction and wastewater treatment plant (WWTP) infrastructure may serve as concentrated point sources of contamination of antibiotic-resistant bacteria and antibiotic resistance genes. In this study, we focused on the distribution of antimicrobial-resistant E. coli in two rivers with large drainage areas and different urbanisation levels. E. coli from Kaoping River with drainage mainly from livestock farming had higher resistance to antibiotics (e.g. penicillins, tetracyclines, phenicols, aminoglycosides, and sulpha drugs) and presented more positive detection of antibiotic-resistance genes (e.g. ampC, blaTEM, tetA, and cmlA1) than that from Tamsui River. In Kaoping River with a lower percentage of sewer construction nearby (0–30%) in contrast to a higher percentage of sewer construction (55–92%) in Tamsui River, antimicrobial-resistant E. coli distribution was related to livestock farming waste. In Tamsui River, antimicrobial resistant E. coli isolates were found more frequently in the downstream drainage area of WWTPs with secondary water treatment than that of WWTPs with tertiary water treatment. The Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR showed that the fingerprinting group was significantly related to the sampling site (p < 0.01) and sampling date (p < 0.05). By utilising ERIC-PCR in conjunction with antibiotic susceptibility and antibiotic-resistance gene detection, the relationship among different strains of E. coli could be elucidated. Furthermore, we identified the presence of six extra-intestinal pathogenic E. coli isolates and antibiotic-resistant E. coli isolates near drinking water sources, posing a potential risk to public health through community transmission. In conclusion, this study identified environmental factors related to antibiotic-resistant bacteria and antibiotic-resistance gene contamination in rivers during urban development. The results facilitate the understanding of specific management of different waste streams across different urban areas. Periodic surveillance of the effects of WWTPs and livestock waste containing antibiotic-resistant bacteria and antibiotic-resistance genes on river contamination is necessary.

Simultaneous removal of Cd and ciprofloxacin hydrochloride by ZVI/biochar composite in water: Compound effects and removal mechanism

The combined pollution of heavy metals and antibiotics in wastewater does great harm to the ecological environment in recent years. In this work, ZVI/biochar (Fe@C) was prepared by a simple green method and was used to remove Cd2+ and ciprofloxacin hydrochloride (HCIP) from aqueous solution. The material has shown splendid efficiency in the simultaneous adsorption of Cd2+ and degradation of HCIP. The adsorption isotherms results exhibited that the adsorption capacity of the Fe@C for Cd2+ and HCIP was 367.95 and 262.76 mg/g, respectively. The TOC removal efficiency reached 33.64 % after degradation for 4 h. The adsorption mechanisms of Cd2+ were precipitation adsorption and complex formation with oxygen-containing functional groups, while the HCIP were cation bridging, electrostatic interactions, π-π interaction and hydrogen bonding interaction, and Cd2+ could act as a bridge. The adsorption of Cd2+ was enhanced because of the existence of HCIP. The degradation of HCIP was promoted visibly due to the complexation of Cd2+ and HCIP. The quenching experiments and electron paramagnetic resonance analysis showed that the superoxide free radical (O2·−) rather than SO4·− and ·OH was the main species leading to HCIP degradation. This work provides a simple, green and low-cost way for the preparation of environmental remediation materials, and can effectively achieve co-removal of Cd2+ and HCIP, which has potential application prospects.

The erythromycin sorption removal at environmentally relevant concentration based on molecular imprinted polymer: Performance and mechanism

The antibiotic pollution emerged in different environments has raised a great concern. Adsorption is an effective method to solve the problem. However, conventional adsorbents are not always efficient for antibiotic removal with interferences. Therefore, in this study, molecularly imprinted polymer (EMIP) with selective adsorption ability was prepared to remove a typical antibiotic-erythromycin (ERY) at environmentally relevant concentration. The specific surface area of EMIP was 265.62 m2/g with large pore volume, small pore size and hydrophobic surface. The adsorption capacity of EMIP was increased from 211.08 to 4015.51 μg/g when the concentration of ERY was increased from 5.00 to 100.00 μg/L. The isothermal adsorption process was fitted well with the Langmuir model. The adsorption kinetic could be well described by the pseudo-second-order model. With co-existing of interferences, the imprinting factor for ERY was 2.57, which demonstrated EMIP had good adsorption selectivity. After five consecutive adsorption-desorption experiments, the adsorption capacity of EMIP was still over 80%. The results of molecular dynamic simulation showed the adsorption energy between ERY and EMIP was high, which was favorable for ERY adsorption removal. Hopefully, the results of this study could provide new insights for trace antibiotic removal by molecular imprinting polymers in different aqueous environments.

Response of biofilm–based systems for antibiotics removal from wastewater: Resource efficiency and process resiliency

Biofilm–based systems have efficient stability to cope–up influent shock loading with protective and abundant microbial assemblage, which are extensively exploited for biodegradation of recalcitrant antibiotics from wastewater. The system performance is subject to biofilm types, chemical composition, growth and thickness maintenance. The present study elaborates discussion on different type of biofilms and their formation mechanism involving extracellular polymeric substances secreted by microbes when exposed to antibiotics–laden wastewater. The biofilm models applied for estimation/prediction of biofilm–based systems performance are explored to classify the application feasibility. Further, the critical review of antibiotics removal efficiency, design and operation of different biofilm–based systems (e.g. rotating biological contactor, membrane biofilm bioreactor etc.) is performed. Extending the information on effect of various process parameters (e.g. hydraulic retention time, pH, biocarrier filling ratio etc.), the microbial community dynamics responsible of antibiotics biodegradation in biofilms, the technological problems, related prospective and key future research directions are demonstrated. The biofilm–based system with biocarriers filling ratio of ∼50–70% and predominantly enriched with bacterial species of phylum Proteobacteria protected under biofilm thickness of ∼1600 μm is effectively utilized for antibiotic biodegradation (>90%) when operated at DO concentration ≥3 mg/L. The C/N ratio ≥1 is best suitable condition to eliminate antibiotic pollution from biofilm–based systems. Considering the significance of biofilm–based systems, this review study could be beneficial for the researchers targeting to develop sustainable biofilm–based technologies with feasible regulatory strategies for treatment of mixed antibiotics–laden real wastewater.