Antibiotic residue and toxicity assessment of wastewater during the pharmaceutical production processes

From wastewater to clean water: Recent advances on the removal of metronidazole, ciprofloxacin, and sulfamethoxazole antibiotics from water through adsorption and advanced oxidation processes (AOPs)

Antibiotics released into water sources pose significant risks to both human health and the environment. This comprehensive review meticulously examines the ecotoxicological impacts of three prevalent antibiotics-ciprofloxacin, metronidazole, and sulfamethoxazole-on the ecosystems. Within this framework, our primary focus revolves around the key remediation technologies: adsorption and advanced oxidation processes (AOPs). In this context, an array of adsorbents is explored, spanning diverse classes such as biomass-derived biosorbents, graphene-based adsorbents, MXene-based adsorbents, silica gels, carbon nanotubes, carbon-based adsorbents, metal-organic frameworks (MOFs), carbon nanofibers, biochar, metal oxides, and nanocomposites. On the flip side, the review meticulously examines the main AOPs widely employed in water treatment. This includes a thorough analysis of ozonation (O3), the photo-Fenton process, UV/hydrogen peroxide (UV/H2O2), TiO2 photocatalysis, ozone/UV (O3/UV), radiation-induced AOPs, and sonolysis. Furthermore, the review provides in-depth insights into equilibrium isotherm and kinetic models as well as prospects and challenges inherent in these cutting-edge processes. By doing so, this review aims to empower readers with a profound understanding, enabling them to determine research gaps and pioneer innovative treatment methodologies for water contaminated with antibiotics.

Insight into the generation of toxic by-products during UV/H2O2 degradation of carbamazepine: Mechanisms, N-transformation and toxicity

Carbamazepine (CBZ) is a widely used anticonvulsant drug that has been detected in aquatic environments. This study investigated the toxicity of its by-products (CBZ-BPs), which may surpass CBZ. Unlike the previous studies, this study offered a more systematic approach to identifying toxic BPs and inferring degradation pathways. Furthermore, quadrupole time-of-flight (QTOF) and density functional theory (DFT) calculations were employed to analyze CBZ-BP structures and degradation pathways. Evaluation of total organic carbon (TOC) and total nitrogen (TN) mineralization rates, revealed carbon (C) greater susceptibility to mineralization compared with nitrogen (N). Furthermore, three rules were established for CBZ decarbonization and N removal during degradation, observing the transformation of aromatic compounds into aliphatic hydrocarbons and stable N-containing organic matter over time. Five potentially highly toxic BPs were screened from 14 identified BPs, with toxicity predictions guiding the selection of commercial standards for quantification and true toxicity testing. Additionally, BP207 emerged as the most toxic, supported by the predictive toxicity accumulation model (PTAM). Notably, highly toxic BPs feature an acridine structure, indicating its significant contribution to toxicity. These findings offered valuable insights into the degradation mechanisms of emerging contaminants and the biosafety of aquatic environments during deep oxidation.

Occurrence, bioaccumulation, fate, and risk assessment of emerging pollutants in aquatic environments: A review

Significant concerns on a global scale have been raised in response to the potential adverse impacts of emerging pollutants (EPs) on aquatic creatures. We have carefully reviewed relevant research over the past 10 years. The study focuses on five typical EPs: pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), drinking water disinfection byproducts (DBPs), brominated flame retardants (BFRs), and microplastics (MPs). The presence of EPs in the global aquatic environment is source-dependent, with wastewater treatment plants being the main source of EPs. Multiple studies have consistently shown that the final destination of most EPs in the water environment is sludge and sediment. Simultaneously, a number of EPs, such as PFASs, MPs, and BFRs, have long-term environmental transport potential. Some EPs exhibit notable tendencies towards bioaccumulation and biomagnification, while others pose challenges in terms of their degradation within both biological and abiotic treatment processes. The results showed that, in most cases, the ecological risk of EPs in aquatic environments was low, possibly due to potential dilution and degradation. Future research topics should include adding EPs detection items for the aquatic environment, combining pollution, and updating prediction models.

Occurrence and fate of pharmaceutical pollutants in wastewater: Insights on ecotoxicity, health risk, and state-of-the-art removal

Pharmaceutical active compound (PhAC) residues are considered an emerging micropollutant that enters the aquatic environment and causes harmful ecotoxicity. The significant sources of PhACs in the environment include the pharmaceutical industry, hospital streams, and agricultural wastes (animal husbandry). Recent investigations demonstrated that wastewater treatment plants (WWTPs) are an important source of PhACs discharging ecosystems. Several commonly reported that PhACs are detected in a range level from ng L-1 to μg L-1 concentration in WWTP effluents. These compounds can have acute and chronic adverse impacts on natural wildlife, including flora and fauna. The approaches for PhAC removals in WWTPs include bioremediation, adsorption (e.g., biochar, chitosan, and graphene), and advanced oxidation processes (AOPs). Overall, adsorption and AOPs can effectively remove PhACs from wastewater aided by oxidizing radicals. Heterogeneous photocatalysis has also proved to be a sustainable solution. Bioremediation approaches such as membrane bioreactors (MBRs), constructed wetlands (CWs), and microalgal-based systems were applied to minimize pharmaceutical pollution. Noteworthy, applying MBRs has illustrated high removal efficiencies of up to 99%, promising prospective future. However, WWTPs should be combined with advanced solutions, e.g., AOPs/photodegradation, microalgae-bacteria consortia, etc., to treat and minimize their accumulation. More effective and novel technologies (e.g., new generation bioremediation) for PhAC degradation must be investigated and specially designed for a low-cost and full-scale. Investigating green and eco-friendly PhACs with advantages, e.g., low persistence, no bioaccumulation, less or non-toxicity, and environmentally friendly, is also necessary.

Airborne antibiotic resistome and microbiome in pharmaceutical factories

Antimicrobial resistance is considered to be one of the biggest public health problems, and airborne transmission is an important but under-appreciated pathway for the spread of antibiotic resistance genes (ARGs) in the environment. Previous research has shown pharmaceutical factories to be a major source of ARGs and antibiotic resistant bacteria (ARB) in the surrounding receiving water and soil environments. Pharmaceutical factories are hotspots of antibiotic resistance, but the atmospheric transmission and its environmental risk remain more concerns. Here, we conducted a metagenomic investigation into the airborne microbiome and resistome in three pharmaceutical factories in China. Soil (average: 38.45%) and wastewater (average: 28.53%) were major contributors of airborne resistome. ARGs (vanR/vanS, blaOXA, and CfxA) conferring resistance to critically important clinically used antibiotics were identified in the air samples. The wastewater treatment area had significantly higher relative abundances of ARGs (average: 0.64 copies/16S rRNA). Approximately 28.2% of the detected airborne ARGs were found to be associated with plasmids, and this increased to about 50% in the wastewater treatment area. We have compiled a list of high-risk airborne ARGs found in pharmaceutical factories. Moreover, A total of 1,043 viral operational taxonomic units were identified and linked to 47 family-group taxa. Different CRISPR-Cas immune systems have been identified in bacterial hosts in response to phage infection. Similarly, higher phage abundance (average: 2451.70 PPM) was found in the air of the wastewater treatment area. Our data provide insights into the antibiotic resistance gene profiles and microbiome (bacterial and non-bacterial) in pharmaceutical factories and reveal the potential role of horizontal transfer in the spread of airborne ARGs, with implications for human and animal health.

A combined evaluation of the characteristics and antibiotic resistance induction potential of antibiotic wastewater during the treatment process

Antibiotic wastewater contains a variety of pollutant stressors that can induce and promote antibiotic resistance (AR) when released into the environment. Although these substances are mostly in concentrations lower than those known to induce AR individually, it is possible that antibiotic wastewater discharge might still promote the AR transmission risk via additive or synergistic effects. However, the comprehensive effect of antibiotic wastewater on AR development has rarely been evaluated, and its treatment efficiency remains unknown. Here, samples were collected from different stages of a cephalosporin production wastewater treatment plant, and the potential AR induction effect of their chemical mixtures was explored through the exposure of the antibiotic-sensitive Escherichia coli K12 strain. Incubation with raw cephalosporin production wastewater significantly promoted mutation rates (3.6 × 103-9.3 × 103-fold) and minimum inhibition concentrations (6.0-6.7-fold) of E. coli against ampicillin and chloramphenicol. This may be attributed to the inhibition effect and oxidative stress of cephalosporin wastewater on E. coli. The AR induction effect of cephalosporin wastewater decreased after the coagulation sedimentation treatment and was completely removed after the full treatment process. A Pearson correlation analysis revealed that the reduction in the AR induction effect had a strong positive correlation with the removal of organics and biological toxicity. This indicates that the antibiotic wastewater treatment had a collaborative processing effect of conventional pollutants, toxicity, and the AR induction effect. This study illustrates the potential AR transmission risk of antibiotic wastewater and highlights the need for its adequate treatment.

Advanced oxidation and biological integrated processes for pharmaceutical wastewater treatment: A review

The stress of pharmaceutical and personal care products (PPCPs) discharging to water bodies and the environment due to increased industrialization has reduced the availability of clean water. This poses a potential health hazard to animals and human life because water contamination is a great issue to the climate, plants, humans, and aquatic habitats. Pharmaceutical compounds are quantified in concentrations ranging from ng/Lto μg/L in aquatic environments worldwide. According to (Alsubih et al., 2022), the concentrations of carbamazepine, sulfamethoxazole, Lutvastatin, ciprofloxacin, and lorazepam were 616-906 ng/L, 16,532-21635 ng/L, 694-2068 ng/L, 734-1178 ng/L, and 2742-3775 ng/L respectively. Protecting and preserving our environment must be well-driven by all sectors to sustain development. Various methods have been utilized to eliminate the emerging pollutants, such as adsorption and biological and advanced oxidation processes. These methods have their benefits and drawbacks in the removal of pharmaceuticals. Successful wastewater treatment can save the water bodies; integrating green initiatives into the main purposes of actor firms, combined with continually periodic awareness of the current and potential implications of environmental/water pollution, will play a major role in water conservation. This article reviews key publications on the adsorption, biological, and advanced oxidation processes used to remove pharmaceutical products from the aquatic environment. It also sheds light on the pharmaceutical adsorption capability of adsorption, biological and advanced oxidation methods, and their efficacy in pharmaceutical concentration removal. A research gap has been identified for researchers to explore in order to eliminate the problem associated with pharmaceutical wastes. Therefore, future study should focus on combining advanced oxidation and adsorption processes for an excellent way to eliminate pharmaceutical products, even at low concentrations. Biological processes should focus on ideal circumstances and microbial processes that enable the simultaneous removal of pharmaceutical compounds and the effects of diverse environments on removal efficiency.

Two-step pyrolytic preparation of biochar for the adsorption study of tetracycline in water

In this study, cow dung biomass was converted into biochar (BC). BC900 was obtained through one-step pyrolysis at 900 °C, while BC700-900 and BC900-700 were obtained via two-step pyrolysis at temperature ranges of 700-900 °C and 900-700 °C, respectively. The primary objective was to investigate the adsorption performance and application value of BCs for tetracycline (TC) in water. The samples underwent characterization using scanning electron microscopy and mapping analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Subsequently, the effects of reaction time, adsorbent dosage, temperature, pH, and ionic strength were analyzed. Based on the fitting results of adsorption kinetics, the pyrolytic BCs exhibited a better fit with the pseudo-secondary kinetic model. The adsorption isotherm indicated monolayer adsorption on the surface of the adsorbents, with maximum adsorption capacities of 158.93 mg/g for BC900-700, 150.15 mg/g for BC700-900, and 142.56 mg/g for BC900, respectively. Furthermore, results from simulated wastewater and regeneration experiments demonstrated that BC900-700 exhibited not only excellent adsorption performance in wastewater but also remarkable regeneration capabilities. The two-step pyrolysis BCs in this study displayed a higher adsorption capacity compared to the one-step pyrolysis BCs in practical applications. These findings provide insights for further exploring the adsorption mechanism and optimizing the process.

Pollutant profile complexity governs wastewater removal of recalcitrant pharmaceuticals

Organic pollutants are an increasing threat for wildlife and humans. Managing their removal is however complicated by the difficulties in predicting degradation rates. In this work, we demonstrate that the complexity of the pollutant profile, the set of co-existing contaminants, is a major driver of biodegradation in wastewater. We built representative assemblages out of one to five common pharmaceuticals (caffeine, atenolol, paracetamol, ibuprofen, and enalapril) selected along a gradient of biodegradability. We followed their individual removal by wastewater microbial communities. The presence of multichemical background pollution was essential for the removal of recalcitrant molecules such as ibuprofen. High-order interactions between multiple pollutants drove removal efficiency. We explain these interactions by shifts in the microbiome, with degradable molecules such as paracetamol enriching species and pathways involved in the removal of several organic pollutants. We conclude that pollutants should be treated as part of a complex system, with emerging pollutants potentially showing cascading effects and offering leverage to promote bioremediation.

Degradation of sulfamethoxazole and antibiotic resistance genes from surface water in the photocatalyst-loading bionic ecosystems

The behavior and removal of sulfamethoxazole (SMX) and 3 typical corresponding antibiotic resistance genes (ARGs) including sul1, sul2, sul3, and 16S rDNA in surface water were investigated in the photocatalyst-loading bionic ecosystems (PCBEs). Synthesized composite photocatalyst g-C3N4/TiO2 showing higher catalytic activity than Fe/g-C3N4/TiO2 was selected in the PCBEs. Five PCBEs, i.e., A-the control (without bionic grass or photocatalyst), B-bionic grass loaded with 4.12 g/m2 g-C3N4/TiO2, C-bionic grass loaded with 8.25 g/m2 g-C3N4/TiO2, D-bionic grass loaded with 12.37 g/m2 g-C3N4/TiO2, and E-bionic grass loaded with 16.5 g/m2 g-C3N4/TiO2 were constructed and operated in a medium-scale running cyclical flume. SMX could be photolyzed efficiently by g-C3N4/TiO2 with an optimal unit load on the bionic grass of 12.37 g/m2. 3-amino-5-methylisooxazole and p-aminobenzene sulfonamide were selected as main intermediates through the analyses of SMX degradation mechanisms and pathways, and detected in the aqueous phase and bionic grass. The intermediates were higher in the underwater part of the bionic grass than the above-water part. The overall removal of SMX ranged from 31.7 % to 82.3 % in 5 PCBEs, and the removal of sul1and sul2 were 0.2 %- 62.9 % in the aqueous phase and 8.4 %-63.2 % in the sediment. PCBE D might be the best construction when SMX and ARGs' removal was considered comprehensively. Moreover, the microbial structures showed Proteobacteria as the most dominant bacterial species had a relative abundance of 22.2 %-26.6 % and 33.4 %-68.2 % in the aquatic phase and sediment respectively, illustrating that the removal of the antibiotic and ARGs was bound up with the variations of dominant bacteria in the ecosystems. The findings illustrated that ecosystems with bionic grass and photocatalysts could be a promising technology for the removal of typical antibiotics and ARGs from surface water.

Contribution of wastewater to antimicrobial resistance: A review article

OBJECTIVES

Antimicrobial resistance (AMR) is a global challenge that has raised concern globally, owing to its detrimental effects on the health and economy of countries. The ever-growing threat of AMR and sources of AMR are still being investigated. Wastewater plays an important role as a habitat for bacteria and an environment conducive to gene transfer. The primary aim of this review was to highlight the contribution of wastewater to AMR.

METHODS

Evidence of AMR in wastewater was drawn from literature published in the last 10 years, from 2012 to 2022.

RESULTS

Wastewater from agricultural practices, pharmaceutical manufacturing plants, and hospital effluents was established to promote AMR. Furthermore, stress factors such as the presence of antibiotics, heavy metals, pH, and temperature initiate and propagate AMR in bacteria living in wastewater. AMR in bacteria from wastewater was established to be either natural or acquired. Wastewater treatment techniques such as membrane filtration, coagulation, adsorption, and advanced oxidation processes have been used to remove resistant bacteria with varying success levels.

CONCLUSION

Wastewater is a major contributor to AMR, and an understanding of its role in AMR is necessary to find a lasting solution. In this regard, the spread of AMR in wastewater should be considered a threat that requires a strategy to stop further damage.

Comparative Investigation of the Spectroscopic Behavior Based on High-Concentrated Solution in Nitrogen and Air Atmospheres

In order to accurately obtain photometric information of high concentration SO42- and other substances in the process industry, the spectroscopy behavior of SO42-, S2-, Ni2+ and Cu2+ in air and nitrogen atmosphere was compared based on the UV-visible spectrophotometer with a nitrogen replacing the oxygen. Different from Ni2+ and Cu2+, the accuracy of SO42- and S2- in the ultraviolet region was effectively improved by using a nitrogen atmosphere (P detection results were regressed within the limited standard range, RE < 5%). The nitrogen atmosphere suppressed the additional light attenuation caused by its absorption of ultraviolet rays by isolating oxygen and was also reflected in the decrease in the degree of red shift of the characteristic wavelength for SO42- with increasing concentration. Therefore, the detection results of SO42- showed an effective improvement in sensitivity. Nevertheless, according to the complementary experimental results and theoretical calculations, in addition to oxygen absorption, the low detection accuracy of SO42- high concentration is also attributed to the reduction of the energy required for electronic excitation per unit group caused by the interaction between SO42- groups, resulting in a deviation of the C-A curve from linearity at high concentrations. The influence of this intermolecular force on the detection results is far more important than oxygen absorption. The research can provide reliable theoretical guidance and technical support for the pollution-free direct measurement of high-concentration solutions in the process industry and promote the sustainable development of the process industry.

High-risk antibiotics positively correlated with antibiotic resistance genes in five typical urban wastewater

Antibiotic resistance genes (ARGs) and antibiotic amount increased within close proximity to human dominated ecosystems. However, few studies assessed the distribution of antibiotics and ARGs in multiple ecosystems especially the different urban wastewater. In this study, the spatial distribution of ARGs and antibiotics across the urban wastewater included domestic, livestock, hospital, pharmaceutical wastewater, influent of the wastewater treatment plant (WWTP) in Northeast China. The q-PCR results showed that ARGs were most abundant in community wastewater and followed by WWTP influent, livestock wastewater, pharmaceutical wastewater and hospital wastewater. The ARG composition differed among the five ecotypes with qnrS was the dominant ARG subtypes in WWTP influent and community wastewater, while sul2 dominant in livestock, hospital, pharmaceutical wastewater. The concentration of antibiotics was closely related to the antibiotic usage and consumption data. In addition to the high concentration of azithromycin at all sampling points, more than half of the antibiotics in livestock wastewater were veterinary antibiotics. However, antibiotics that closely related to humankind such as roxithromycin and sulfamethoxazole accounted for a higher proportion in hospital wastewater (13.6%) and domestic sewage (33.6%), respectively. The ambiguous correlation between ARGs and their corresponding antibiotics was detected. However, antibiotics that exhibited high ecotoxic effects were closely and positively correlated with ARGs and the class 1 integrons (intI1), which indicated that high ecotoxic compounds might affect antimicrobial resistance of bacteria by mediating horizontal gene transfer of ARGs. The coupling mechanism between the ecological risk of antibiotics and bacterial resistance needed to be further studied, and thereby provided a new insight to study the impact of environmental pollutants on ARGs in various ecotypes.

Extracellular polymeric substances-antibiotics interaction in activated sludge: A review

Antibiotics, the most frequently prescribed drugs, have been widely applied to prevent or cure human and veterinary diseases and have undoubtedly led to massive releases into sewer networks and wastewater treatment systems, a hotspot where the occurrence and transformation of antibiotic resistance take place. Extracellular polymeric substances (EPS), biopolymers secreted via microbial activity, play an important role in cell adhesion, nutrient retention, and toxicity resistance. However, the potential roles of sludge EPS related to the resistance and removal of antibiotics are still unclear. This work summarizes the composition and physicochemical characteristics of state-of-the-art microbial EPS, highlights the critical role of EPS in antibiotics removal, evaluates their defense performances under different antibiotics exposures, and analyzes the typical factors that could affect the sorption and biotransformation behavior of antibiotics. Next, interactions between microbial EPS and antibiotic resistance genes are analyzed. Future perspectives, especially the engineering application of microbial EPS for antibiotics toxicity detection and defense, are also emphatically stressed.

Deciphering chloramphenicol biotransformation mechanisms and microbial interactions via integrated multi-omics and cultivation-dependent approaches

BACKGROUND

As a widely used broad-spectrum antibiotic, chloramphenicol is prone to be released into environments, thus resulting in the disturbance of ecosystem stability as well as the emergence of antibiotic resistance genes. Microbes play a vital role in the decomposition of chloramphenicol in the environment, and the biotransformation processes are especially dependent on synergistic interactions and metabolite exchanges among microbes. Herein, the comprehensive chloramphenicol biotransformation pathway, key metabolic enzymes, and interspecies interactions in an activated sludge-enriched consortium were elucidated using integrated multi-omics and cultivation-based approaches.

RESULTS

The initial biotransformation steps were the oxidization at the C₁-OH and C₃-OH groups, the isomerization at C₂, and the acetylation at C₃-OH of chloramphenicol. Among them, the isomerization is an entirely new biotransformation pathway of chloramphenicol discovered for the first time. Furthermore, we identified a novel glucose-methanol-choline oxidoreductase responsible for the oxidization of the C₃-OH group in Sphingomonas sp. and Caballeronia sp. Moreover, the subsequent biotransformation steps, corresponding catalyzing enzymes, and the microbial players responsible for each step were deciphered. Synergistic interactions between Sphingomonas sp. and Caballeronia sp. or Cupriavidus sp. significantly promoted chloramphenicol mineralization, and the substrate exchange interaction network occurred actively among key microbes.

CONCLUSION

This study provides desirable strain and enzyme resources for enhanced bioremediation of chloramphenicol-contaminated hotspot sites such as pharmaceutical wastewater and livestock and poultry wastewater. The in-depth understanding of the chloramphenicol biotransformation mechanisms and microbial interactions will not only guide the bioremediation of organic pollutants but also provide valuable knowledge for environmental microbiology and biotechnological exploitation. Video Abstract.

Antibiotics and antibiotic resistant bacteria/genes in urban wastewater: A comparison of their fate in conventional treatment systems and constructed wetlands

There is a growing concern that the use and misuse of antibiotics can increase the detection of antibiotic resistant genes (ARGs) in wastewater. Conventional wastewater treatment plants provide a pathway for ARGs and antibiotic resistant bacteria (ARB) to be released into natural water bodies. Research has indicated that conventional primary and secondary treatment systems can reduce ARGs/ARB to varying degrees. However, in developing/low-income countries, only 8-28% of wastewater is treated via conventional treatment processes, resulting in the environment being exposed to high levels of ARGs, ARB and pharmaceuticals in raw sewage. The use of constructed wetlands (CWs) has the potential to provide a low-cost solution for wastewater treatment, with respect to removal of nutrients, pathogens, ARB/ARGs either as a standalone treatment process or when integrated with conventional treatment systems. Recently, CWs have also been employed for the reduction of antibiotic residues, pharmaceuticals, and emerging contaminants. Given the benefits of ARG removal, low cost of construction, maintenance, energy requirement, and performance efficiencies, CWs offer a promising solution for developing/low-income countries. This review promotes a better understanding of the performance efficiency of treatment technologies (both conventional systems and CWs) for the reduction of antibiotics and ARGs/ARB from wastewater and explores workable alternatives.