Ecotoxicological Effects of Microplastics Combined With Antibiotics in the Aquatic Environment: Recent Developments and Prospects.

Both microplastics and antibiotics are commonly found contaminants in aquatic ecosystems. Microplastics have the ability to absorb antibiotic pollutants in water, but the specific adsorption behavior and mechanism are not fully understood, particularly in relation to the impact of microplastics on toxicity in aquatic environments. We review the interaction, mechanism, and transport of microplastics and antibiotics in water environments, with a focus on the main physical characteristics and environmental factors affecting adsorption behavior in water. We also analyze the effects of microplastic carriers on antibiotic transport and long-distance transport in the water environment. The toxic effects of microplastics combined with antibiotics on aquatic organisms are systematically explained, as well as the effect of the adsorption behavior of microplastics on the spread of antibiotic resistance genes. Finally, the scientific knowledge gap and future research directions related to the interactions between microplastics and antibiotics in the water environment are summarized to provide basic information for preventing and treating environmental risks. Environ Toxicol Chem 2024;00:1-12. © 2024 SETAC.

Fluoroquinolone antibiotics in the aquatic environment: environmental distribution, the research status and eco-toxicity.

The increasing presence of fluoroquinolone (FQ) antibiotics in aquatic environments is a growing concern due to their widespread use, negatively impacting aquatic organisms. This paper provides an overview of the environmental distribution, sources, fate, and both single and mixed toxicity of FQ antibiotics in aquatic environments. It also examines the accumulation of FQ antibiotics in aquatic organisms and their transfer into the human body through the food chain. The study identifies critical factors such as metabolism characteristics, physiochemical characteristics, light, temperature, dissolved oxygen, and environmental compatibility that influence the presence of FQ antibiotics in aquatic environments. Mixed pollutants of FQ antibiotics pose significant risks to the ecological environment. Additionally, the paper critically discusses advanced treatment technologies designed to remove FQ antibiotics from wastewater, focusing on advanced oxidation processes (AOPs) and electrochemical advanced oxidation processes (EAOPs). The discussion also includes the benefits and limitations of these technologies in degrading FQ antibiotics in wastewater treatment plants. The paper concludes by proposing new approaches for regulating and controlling FQ antibiotics to aid in the development of ecological protection measures.

Synergistic enhanced activation of peroxymonosulfate by heterojunction Co3O4-CuO@CN for removal of oxytetracycline: Performance, mechanism, and stability.

Metal-organic frameworks (MOFs) as precursors for catalysts has drawn growing attentions. In this study, heterojunction Co3O4-CuO doped carbon materials (noted as Co3O4-CuO@CN) were prepared by direct carbonization of CuCo-MOF in air. It was found that the Co3O4-CuO@CN-2 exhibited excellent catalytic activity with the highest Oxytetracycline (OTC) degradation rate of 0.0902 min-1 at 50 mg/L of Co3O4-CuO@CN-2 dosage, 2.0 mM of PMS and 20 mg/L of OTC, which was 4.25 and 4.96 times that of CuO@CN and Co3O4@CN, respectively. Furthermore, Co3O4-CuO@CN-2 was efficient over a wide pH range (pH 1.9-8.4), and possessed good stability and reusability without OTC degradation decrease after five consecutive uses at pH 7.0. In a comprehensive analysis, the rapid regeneration of Cu(II) and Co(II) is responsible for their excellent catalytic performance, and the p-p heterojunction structure formed between Co3O4 and CuO acts as an intermediary of electron transfer to accelerate PMS decomposition. Moreover, it was interesting to find that Cu rather than Co species played a vital role in the PMS activation. The quenching experiments and electron paramagnetic resonance demonstrated that .OH, SO4•-, and 1O2 were the reactive species responsible for oxidation of OTC and the non-radical pathway triggered by 1O2 was dominant.

The Research Status, Potential Hazards and Toxicological Mechanisms of Fluoroquinolone Antibiotics in the Environment.

Fluoroquinolone antibiotics are widely used in human and veterinary medicine and are ubiquitous in the environment worldwide. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect is reviewed based on in vitro and in vivo experiments referring to many organisms, such as microorganisms, cells, higher plants, and land and aquatic animals. Furthermore, a comparison of the various toxicology mechanisms of fluoroquinolone antibiotic residues on environmental organisms is made. This study identifies gaps in the investigation of the toxic effects of fluoroquinolone antibiotics and mixtures of multiple fluoroquinolone antibiotics on target and nontarget organisms. The study of the process of natural transformation toward drug-resistant bacteria is also recognized as a knowledge gap. This review also details the combined toxicity effect of fluoroquinolone antibiotics and other chemicals on organisms and the adsorption capacity in various environmental matrices, and the scarcity of data on the ecological toxicology evaluation system of fluoroquinolone antibiotics is identified. The present study entails a critical review of the literature providing guidelines for the government to control the discharge of pollutants into the environment and formulate policy coordination. Future study work should focus on developing a standardized research methodology for fluoroquinolone antibiotics to guide enterprises in the design and production of drugs with high environmental biocompatibility.

Synthesis of Bimetallic FeCu-MOF and Its Performance as Catalyst of Peroxymonosulfate for Degradation of Methylene Blue.

Bimetallic MOFs have recently emerged as promising materials for wastewater treatment based on advanced oxidation processes. Herein, a new bimetallic MOF (FeCu-MOF) was fabricated by hydrothermal process. The structural, morphological, compositional and physicochemical properties of the as-synthesized bimetallic FeCu-MOF were characterized by XRD, FT-IR, SEM, TEM, BET, and XPS. TEM and XPS confirmed the homogeneous distribution of CuO2 nanoparticles in the as-synthesized materials. The result of wastewater treatment indicated that 100% of MB was removed by 6.0 mM PMS activated with 0.6 g/L of FeCu-MOF in 30 min. The high catalytic performance of FeCu-MOF was probably due to the accelerated electron and mass transfer resulting from the existence of a homogeneous distribution of unsaturated metal sites and an abundant mesoporous structure. The obtained results from the competitive quenching tests demonstrated that sulfate radicals (SO4•-) were the major species responsible for MB oxidation. In addition, hydroxyl (·OH) and singlet oxygen (1O2) also had a nonnegligible role in the MB removal. Interestingly, the addition of acetate ion (CHCOO-) promoted the removal of MB while other anions (including NO2-, H2PO4-, SO42-, HPO42-, and HCO3-) inhibited the MB removal. Furthermore, a possible mechanism based on both heterogeneous and homogeneous activation of PMS was proposed, along with the MB degradation mechanism.

Effect of temperature on fermentative VFAs production from waste sludge stimulated by riboflavin and the shifts of microbial community.

Fermentative volatile fatty acids (VFAs) production from waste activated sludge (WAS) under moderate temperature is a promising way for resource and energy regeneration in municipal wastewater treatment plants (MWTPs). In this study, the effect of temperature on VFAs production and the associated microbial community from riboflavin-assisted WAS fermentation were investigated. Three fermentative reactors under 25, 35 and 55 °C were operated for 30 days, respectively. The results indicated that riboflavin enhanced VFAs production from WAS fermentation under moderate temperatures (25 °C, 35 °C), increasing conversion of organic matters to bioavailable substrates for the subsequent acidification process. Although a small dosage of riboflavin (1.0 ± 0.05 mM) hardly inhibited the methanogenic process, it could mediate the electron sink for VFAs under lower temperatures. This in turn increased the accumulation of acetic and propionic acids (up to 234 mg/g of volatile suspended solids) and their proportions relative to the total VFAs, being efficient electron donors and carbon sources for nutrient removal in MWTPs. Furthermore, microbial communities were shifted in response to temperature, and riboflavin stimulated the special fermentative bacteria under room temperature and mesophilic conditions. The study suggested a feasible and eco-friendly method to improve VFAs production from crude WAS at a relatively lower temperature.

PMS activation by magnetic cobalt-N-doped carbon composite for ultra-efficient degradation of refractory organic pollutant: Mechanisms and identification of intermediates.

Refractory organic pollutant effluent has led to severe water pollution. In this study, magnetic Co-N-doped carbon hybrid catalysts (Co-NC-x) were fabricated using a facile cation exchange combined pyrolysis and self-reduction technique to activate peroxymonosulfate (PMS) for rehabilitation of the water environment. Factors affecting the catalytic activity of the Co-NC-850 were comprehensively examined. 100% of RhB degradation efficiency within 20 min was achieved in the Co-NC-850/PMS system at the optimum conditions (C0 = 80 mg L-1, catalyst loading 0.025 g L-1, PMS concentration 0.8 mM, native pH and 25 °C). The electron paramagnetic resonance measurements and competitive quenching tests demonstrated that a sulfate radical (SO4•-) and singlet oxygen (1O2) account for RhB degradation in the Co-NC-850/PMS system, and 1O2 contributed ~86.2% to RhB removal. The synergistic effect of Co0 nanoparticles (NPs) and NC on Co-NC-850 might induce a predominant non-radical route to trigger PMS activation for RhB degradation. Direct oxidation of O2•- by a hydroxyl radical (•OH) might be the crucial process for forming 1O2. Magnetic response and successive cycles verified that Co-NC-850 has superior separable performance and reusability. This innovative magnetic Co-NC-850 hybrid catalyst for PMS activation delivered vast potential for disintegration of refractory organic contaminants.

Selective and leaching-resistant palladium catalyst on a porous polymer support for phenol hydrogenation.

Selective hydrogenation of phenol is promising for the utilization of renewable lignocellulose and production of cyclohexanone that usually relies on petroleum, but it is challenging to simultaneously achieve high activity and selectivity. Herein, we report an amino-functionalized nanoporous polymer stabilized palladium nanoparticle catalyst, which is prepared via a one-pot co-polymerization method, as highly active and selective catalysts for the phenol hydrogenation, giving cyclohexanone selectivity over 99.5% with full conversion of phenol under mild reaction conditions without any soluble additives. Importantly, the palladium leaching was efficiently hindered, maintaining the catalytic performances in continuously recycle tests. In contrast, the commercial palladium catalysts exhibit much lower selectivity and obvious deactivation because of the palladium leaching.

Contamination of drinking water by neonicotinoid insecticides in China: Human exposure potential through drinking water consumption and percutaneous penetration.

Neonicotinoids (NEOs) are the most widely used pesticides and have posed a serious threat to human health. However, data on human exposure to NEOs are extremely scarce. To bridge this gap, human exposure potential of NEOs through drinking water consumption and percutaneous penetration was evaluated with the influences of 17 age groups, 4 seasons, 6 regions, and 2 genders. The results showed that drinking water in the present study had an upper middle level of NEO contamination. Anthropogenic activity and weather condition played important roles in the regional distribution of NEOs in tap water. For both children and adults, NEOs intake from drinking water exposure (NDE) and percutaneous exposure (NPE) in the south regions of China are significantly higher than those in the north regions, while the order of NDE and NPE by season is summer > spring = autumn > winter. Furthermore, human age and gender also have remarkable impacts on NDE and NPE. The age groups of children subjected to the highest NDE and NPE were 9 months - 2 years old and 9-12 years old, respectively. This study provides insights into the role of seasonal and regional influence, age and gender in the risk of drinking water and percutaneous exposure to NEOs.

Nano-porous bimetallic CuCo-MOF-74 with coordinatively unsaturated metal sites for peroxymonosulfate activation to eliminate organic pollutants: Performance and mechanism.

The importance of clean water resources for maintaining sustainable development of society is self-evident. In this study, bimetallic metal-organic framework (CuCo-MOF-74) was synthesized and characterized by XRD, FT-IR, SEM, TEM, BET, and XPS techniques. The structural analysis results revealed that CuCo-MOF-74 was nano-porous materials with coordinatively unsaturated metal sites. With the addition of PMS, Cu1Co1-MOF-74 exhibited high activity for methylene blue (MB) removal (100% degradation) within 30 min under low 50 mg/L catalyst dosage. The effects of catalyst dosage, PMS dosage, MB concentration, initial pH, and common anions were evaluated. Quenching reactions and EPR studies revealed the coexistence of sulfate radical (SO4•-), hydroxyl radical (·OH), and singlet oxygen (1O2), which was attributed to the potential in-situ recycling of cobalt and copper species (Co(III)→Co(II), Cu(II)→Cu(I))). Fukui index (f0) and dual descriptor (Δf) by Density functional theory (DFT) calculations were applied to predict the most reactive sites of MB. Meanwhile, the possible degradation pathway of MB was proposed with the help of oxidative intermediates identified by UPLC-MS.

Magnetic Fe3O4-N-doped carbon sphere composite for tetracycline degradation by enhancing catalytic activity for peroxymonosulfate: A dominant non-radical mechanism.

The design of sustainable, effective and recyclable hybrid catalysts for advanced oxidation processes is highly significant for remediation of the water environment. In this study, we synthesized magnetic Fe3O4-N-doped carbon sphere composite catalysts (Fe3O4-NCS-x) for efficient removal of tetracycline by activating peroxymonosulfate (PMS). The Fe3O4-NCS-x composite was obtained by facile hydrothermal treatment of chitosan-iron complexes followed by pyrolysis. The unique structure of N-doped carbon spheres embedded in Fe3O4 nanoparticles intensified the electron transport, consequently improving the catalytic activity via a synergistic effect. Factors influencing the catalytic activity of the Fe3O4-NCS-2 were systematically investigated. High degradation efficiency of TC-97.1% within 1 h-was achieved in this Fe3O4-NCS-2/PMS system under the optimum conditions (C0 = 20 mg L-1, catalyst dosage 0.2 g L-1, PMS concentration 2.4 mM, native pH and 25 °C). The inhibitory effect of anions in the water matrix decreased in the order Cl- > NO3- > SO42- > CH3COO- > HCO3-. The obtained results from the competitive quenching tests and electron paramagnetic resonance measurements demonstrated that singlet oxygen (1O2), a non-radical species, plays a major role in TC degradation. It is estimated that 1O2 and hydroxyl radicals (·OH) contributed ∼65.2% and ∼24.2% to TC degradation in the Fe3O4-NCS-2/PMS system, respectively. The M-H hysteresis loop of Fe3O4-NCS-2 revealed that its saturation moment is 56 emu g-1. Magnetic responsive behavior and consecutive runs confirmed that Fe3O4-NCS-2 possesses remarkable separation performance and desirable reusability. This novel magnetic Fe3O4-NCS-2 composite activator for PMS promises great potential in TC degradation.

Environmental distribution, transport and ecotoxicity of microplastics: A review.

Microplastics (MPs) have become a global environmental pollutant because of their unique properties. The extensive MP toxicity reports have focused on the aquatic environment, while the pervasive MP contamination in the soil and air has largely been overlooked. This review summarizes the abundance, sources and transport of MPs in different environments. It analyzes the toxicity of MPs based on various environmentally relevant bacterial, cellular, plant, aquatic animal and mammalian test groups, using both in vitro and in vivo experiments. The combined toxicity effects of MPs and various other environmental pollutants on ecosystems are also discussed. Currently, data on the adverse effects on combined MP toxicity are very limited. Thus, a systematic assessment of the environmental risk in different environments and in various species from MPs is challenging. Thus, this review proposes the possible risks and identifies the knowledge gaps posed by MPs to food safety and human health.

A review of microplastics in the aquatic environmental: distribution, transport, ecotoxicology, and toxicological mechanisms.

The interactions between microplastics (MPs) and aquatic organisms are becoming increasingly frequent due to the extensive distribution of MPs in aquatic environments. MPs from the aquatic environment tend to accumulate and move through living organisms. Therefore, MPs can affect human health though the food chain and human consumption. In this brief review, the environmental distribution, sources, and transport of MPs are reviewed, and the potential consequences of the presence of MPs in the aquatic environment to human food are discussed. This review also summarized the toxicity effects and toxicity mechanisms of MPs based on various environmentally relevant test species and discussed the combined toxicity effects of MPs and various pollutants in aquatic ecosystems. The knowledge of the adverse effects on combined toxicity and the mechanism of MPs toxicity are very limited. Thus, a systematic assessment of the aquatic environmental risk in various species from MPs is challenging. In the end, we identify the knowledge gaps that need to be filled and provide suggestions for future research.

Exposure to polycyclic aromatic hydrocarbons (PAHs) in people living in urban and rural areas as revealed by hair analysis.

Some polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic to humans. However, little is known about PAH exposure to people living in urban and suburban areas through comparative studies. Some studies have indicated that human hair can be used as a noninvasive biomarker of PAH exposure. Therefore, we collected hair samples from 66 volunteers from Nanjing and Ningbo, China, to detect PAH concentrations in this work. The highest levels in the hair samples were found in phenanthrene > anthracene > naphthalene among the parent PAHs. Sixteen parent PAHs showed higher concentrations in the samples from Nanjing than in the samples from Ningbo. Significantly higher levels of some PAHs were observed in male hair than in female hair in Nanjing, and in hair from smokers than in hair from non-smokers in both Nanjing and Ningbo. In addition, there was a significant effect of the age on the concentration of low-molecular-weight PAHs and ∑PAHs in human hair in both Nanjing and Ningbo. Studying the inter-chemical associations between these PAHs indicated similarities and differences between Nanjing and Ningbo.

ZnO nanoparticles: recent advances in ecotoxicity and risk assessment.

The widespread application of zinc oxide nanoparticles (nano-ZnO) has received increasing attention because of their potential risks to human health and the environment. This review summarizes the relationship between the toxic effects and physicochemical properties of nano-ZnO and the underlying toxicity mechanisms of nano-ZnO. This study presents the possible human health hazards posed by nano-ZnO exposure and the biotoxicity to bacteria, algae, higher plants, aquatic animals, terrestrial invertebrates and vertebrates in vitro and in vivo. The advances in research on the ecotoxicity of nano-ZnO and the potential risks to human health are discussed. Finally, the current research deficiencies in this area are identified, and recommendations for future research are proposed.

Nanoporous bimetallic metal-organic framework (FeCo-BDC) as a novel catalyst for efficient removal of organic contaminants.

In this work, we report on the synthesis and characterization of nanoporous bimetallic metal-organic frameworks (FeCo-BDC). Effects of synthesis time and temperature on the structures, morphology, and catalytic performance of FeCo-BDC were investigated. Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) were used to reveal the morphological and textural characteristics. The crystal structure and chemical composition of FeCo-BDC were determined by means of X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) measurements. Interestingly, FeCo-BDC grew into the same crystal structure with different morphology in the temperature of 110-150 °C with 12-48 h. The heterogeneous catalytic activity of FeCo-BDC was tested to activate peroxydisulfate (PDS) and peroxymonosulfate (PMS) for removal of methylene blue (MB). The results found that FeCo-BDC synthesized at 150 °C with 24 h exhibited the best catalytic performance for PMS and obtained 100% of MB removal within 15 min. The abundant unsaturated metal active sites of Fe(II) and Co(II) in the skeleton of FeCo-BDC made a great contribution to the generation of sulfate () and hydroxyl radicals (OH), which resulted in the excellent performance for MB degradation.

A review of organophosphorus flame retardants (OPFRs): occurrence, bioaccumulation, toxicity, and organism exposure.

Organophosphorus flame retardants (OPFRs) are increasingly being applied as flame retardants due to their unique properties. OPFRs are commonly detected in various environmental matrices, and organisms are extensively exposed to them. Considering the adverse effects of OPFRs, many researchers have devoted their attention to environmental risk assessments. This review outlines the current knowledge regarding the toxicity of OPFRs based on both in vitro and in vivo experiments in various environmentally relevant test species. The production, absorption, bioaccumulation, and biomagnification of OPFRs in animals and humans are also described. The joint effects of OPFRs and their coexisting characteristics are also discussed based on the limited available data and results. Finally, knowledge gaps and perspectives for future exposure studies of OPFRs in animals and humans are identified.

Cu@Co-MOFs as a novel catalyst of peroxymonosulfate for the efficient removal of methylene blue.

In this study, for the first time, we describe the single step synthesis of a Cu particle-doped cobalt-based metal-organic framework (Cu@Co-MOF) using a hydrothermal method. The as-prepared materials were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy-energy disperse spectroscopy, thermogravimetry, and X-ray photoelectron spectroscopy, which confirmed the incorporation of zero-valent copper on the surface of the Co-MOFs. The heterogeneous catalytic activity of Cu@Co-MOFs was tested to activate peroxymonosulfate (PMS) for the removal of methylene blue (MB). The ratio of n(Cu)/n(Co) in the Cu@Co-MOFs showed a strong impact on the catalytic activity of the Cu@Co-MOFs, whereas a n(Cu)/n(Co) of 1 : 1 exhibited the best catalytic performance and obtained 100% MB removal within 30 min. The effects of initial pH, reaction temperature, PMS concentration, and catalyst dosages were investigated in this study. The stability and reusability of the Cu@Co-MOFs were also investigated. The results showed a low decline in the MB removal with the increase in cycle numbers, whereas 100% MB was removed by prolonging the reaction time. Heterogeneous reactions taking place in the pores and surface of the Cu@Co-MOFs played an important role in the generation of the sulfate radicals (SO4˙-) and hydroxyl radicals (·OH) that were the primary reactive species responsible for MB degradation.

A review on silver nanoparticles-induced ecotoxicity and the underlying toxicity mechanisms.

Silver nanoparticles (Ag-NPs) are increasingly being applied in many consumer products due to their unique properties. Widespread use of Ag-NPs leads to an increasing human exposure to Ag-NPs in many different pathways. This review summarized the toxicity mechanisms of Ag-NPs based on various environmentally relevant test species, such as bacteria, cells, plants, aquatic animals and mammals, in both in vitro and in vivo experiments. Nanoparticles were usually exposed to combination chemicals but to single chemicals in the environment and thereby exert combined toxicities to the organisms. Therefore, the joint effects of nanomaterials and their co-existing characteristics were also discussed. The current knowledge gaps and safe product designs of Ag-NPs have been discussed in detail. The limited and existing data implied that understanding the toxicity mechanisms is crucial to the future research development of nanomaterials.

Parental transfer of perfluorooctane sulfonate and ZnO nanoparticles chronic co-exposure and inhibition of growth in F1 offspring.

Perfluorooctane sulfonate (PFOS) and ZnO nanoparticles (Nano-ZnO) are two kinds of environmental contaminants that have been frequently detected in natural waters. The potential joint toxicity of PFOS and nano-ZnO remains to be fully elucidated. The objective of this study was to evaluate co-exposure effects of PFOS and nano-ZnO on growth in initial generation (F0) zebrafish after chronic exposure and to examine possible parental transfer of PFOS and nano-ZnO transgenerational effects on the growth of first generation (F1) larvae. When zebrafish (2 h after incubation) were exposed to single- and co-exposure groups for 120 days, bioconcentration resulted in significantly less growth as measured by body length and body weight, higher mortality, and less spawning in the F0 generation. These effects were possibly due to the down-regulation of the expression of Vtg1 genes along with a sex hormone (T/E2) involved in the hypothalamus-pituitary-gonad (HPG) axis. Furthermore, after long-term exposure, less fertilization, less hatching, greater mortality and more malformation were found in the F1 generation. The down-regulation of genes and hormones might be responsible for transgenerational toxicity. This study suggested that chronic exposure to PFOS and nano-ZnO adversely impacts development, reproduction in the F0 generation, and offspring embryonic growth.