Interaction of Microplastics with Antibiotics in Aquatic Environment: Distribution, Adsorption, and Toxicity

Adsorption and desorption of phenanthrene and 1-hydroxyphenanthrene by goethite-coated polyvinyl chloride

Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments, and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics. In this study, three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene (PHE) and 1-hydroxyphenanthrene (1-OHPHE), and the effect of mucin on desorption was investigated. The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites. With the increase of the cover degree, the adsorption of PHE decreased because of the decrease in hydrophobicity; while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond. The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+ bridging. The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity. Mucin promoted the desorption of PHE through competitive adsorption, and inhibit the desorption of 1-OHPHE through hydrophobic interaction, hydrogen bonding and Ca2+ bridging. This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics, briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties, and emphasized the different environmental behaviors of pollutants.

Aging characteristics of polylatic acid microplastics and their adsorption on hydrophilic organic pollutants: mechanistic investigations and theoretical calculations

The extended persistence of microplastics (MPs) in aquatic habitats can result in the uptake and accumulation of various pollutants, thereby creating a serious risk to the ecosystem. The research explored how various weathering environments affect the physicochemical traits of polylactic acid (PLA) MPs and their capacity to adsorb common hydrophilic organic contaminants, such as benzoic acid (BA), sulfamethoxazole (SMZ), and sulfamethazine (SMR). The results showed that the ability to adsorb was affected by pH and was dependent on the pHPZC of PLA as well as the pKa values of the contaminants. Calculated DFT results were consistent with the actual adsorption capacity of PLA (SMX > BA > SMR). The main adsorption mechanisms included hydrophobic interaction, hydrogen bonding, and electrostatic attraction, with hydrophobicity predominating. Additionally, charge-assisted hydrogen bond (CAHB) and partition effect enhanced adsorption under specific conditions. Compared to virgin PLA, the adsorption capacity of aged PLA for hydrophilic organic pollutants generally improved, with APLA showing the most increase. The impact of oxygen concentration, surface area, and crystallinity on the adsorption ability of MPs was minimal, whereas surface charge became the primary physicochemical factor influencing the adsorption performance of aged PLA. This study would provide important theoretical references and data to deepen the understanding of the environmental behavior of PLA and its potential environmental risks.

From wastewater to sludge: The role of microplastics in shaping anaerobic digestion performance and antibiotic resistance gene dynamics

The presence of microplastics (MPs) in wastewater treatment plants (WWTPs) disrupt processes and threaten the effectiveness of anaerobic digestion (AD), raising critical environmental and operational concerns. This review assesses MP occurrence in WWTPs and its effects on biogas production and the fate of antibiotic resistance genes (ARGs) during AD to understand their impact on process efficiency and environmental health. Polypropylene (PP) and polyethylene (PE) are the most prevalent types of MPs which are found in WWTP influent at an average concentration of 801.5 particles per liter (P/L), decrease to 38.3 P/L in effluent, and accumulate in sludge at 70.5 P/L. The effect of MPs on AD performance is influenced by MP type, concentration, size, and AD conditions (i.e., feed substrate, reactor configuration, temperature, and incubation time). For example, certain MPs (polyamide 7 (PA7) and PP) increase methane production by 39.5 %, while aged MPs decrease it by 47.2 %. The review also explores how AD drives MP degradation mechanisms like oxidation, hydrolysis, mechanical stress, and biodegradation. Additionally, MPs significantly impact ARGs, with abundance increasing by 0.4-514.4 %, especially with aged MPs. Mechanistic effects of MPs on ARGs dissemination were also discussed, including horizontal gene transfer (reactive oxygen species production, cell membrane permeability, extracellular polymeric substances secretion, and ATP dynamics), vertical gene transfer, microbial community, and adsorbing pollutants. This analysis provides insights into the complex interactions between MPs, microbial processes, and ARGs, highlighting their implications for wastewater treatment and biogas production systems.

Integration of machine learning and meta-analysis reveals the behaviors and mechanisms of antibiotic adsorption on microplastics

Microplastics (MPs) can adsorb antibiotics (ATs) to cause combined pollution in the environment. Research on this topic has been limited to specific types of MPs and ATs, resulting in inconsistent findings, particularly for the influencing factors and adsorption mechanisms. Therefore, this study combined meta-analysis and machine learning to analyze a dataset comprising 6805 records from 123 references. The results indicated that polyamide has the highest adsorption capacity for ATs, which is primarily attributed to the formation of hydrogen bonds by its N-H groups, and MPs exhibited the strongest affinity for chlortetracycline because the CO and -Cl groups in chlortetracycline form hydrogen and halogen bonds with MPs. Moreover, the particle size, MP and AT concentrations, and pH were key factors affecting the adsorption process with notable interaction effects. Hydrogen bonding and electrostatic interaction were commonly involved in the adsorption of ATs onto MPs. Finally, an interactive graphical user interface was deployed to predict the adsorption amount, affinity constant, and maximum adsorption capacity of MPs for ATs, with results aligning well with the latest published data. This study provides crucial insights into the behavior of MPs carrying ATs, thereby facilitating accurate assessment of the combined environmental risks of them.

Ultrahigh-efficiency and synchronous removal of microplastics-tetracycline composite pollutants via S-scheme core-shell magnetic nanosphere

Composite pollution in aquatic environments has become a critical challenge, with emerging pollutants like antibiotics and microplastics (MPs) posing significant ecological risks. The interaction between antibiotics and MPs complicates treatment processes and underscores the need for targeted removal strategies. This study focused on a novel S-scheme core-shell magnetic nanosphere, Fe3O4@TiO2-C4N, combining TiO2 and C4N to form a heterojunction that enhances photocatalytic performance. The S-scheme heterojunction improves redox ability, enabling efficient degradation of composite pollutants under light irradiation. After 12 h reaction, Fe3O4@TiO2-C4N achieved 97.3 % removal for polyethylene (PE) MPs and 96.0 % removal for tetracycline (TC), surpassing existing TiO2-based catalysts. Moreover, Fe3O4@TiO2-C4N demonstrated excellent magnetic recyclability rate of 77.07 %, enabling easy catalyst recovery and reuse. Meanwhile, Fe3O4@TiO2-C4N outstands on TC removal at an optimal concentration (200 mg L-1). Notably, MPs in composite pollution scenarios showed higher removal rates than individual pollutants. This study highlights the powerful role of Fe3O4@TiO2-C4N as a promising photocatalyst for the joint degradation of multiple composite pollutants in aquatic environment, providing an innovative solution for addressing water pollution challenges. Furthermore, its real-world application potential is demonstrated by its efficient recovery, long-term stability, and compatibility with existing water treatment systems, paving the way for large-scale environmental remediation technologies.

Polymer-Specific Impacts of Microplastics on Mineral Retention and Soil Stability

Microplastics (MPs) contamination threatens soil structure and function. We quantified how six common polymers: polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene-terephthalate (PET), polyurethane (PU) and polyvinyl-chloride (PVC), interact with minerals in four textural (sandy-clay-loam, silty-clay-loam, clay-loam and sandy-loam). Retention, porosity, and aggregate stability were measured with SEM, FTIR, zeta-sizer, and X-ray-diffraction. Low-density polymers (PE and PP) accumulated at 5-10 mg kg-1 in fine soils and raised stability by 20 %. High-density polymers (PVC and PET) were concentrated in the clay fractions of coarse soils and reduced macroporosity by ≤ 15 %. Allophane and kaolinite adsorbed 19 % and 12 % of low-density MPs, respectively, whereas hematite and hornblende retained ≤ 7 %. Polymer density and mineral surface area jointly govern MP fate and the resulting shifts in soil physical quality. These polymer-specific mechanisms support the targeted mitigation and refined risk assessment of terrestrial microplastic pollution.

Insights into the Imprinting and Rebinding Performance of Molecularly Imprinted Hybrids for Bisphenol A and Bisphenol F

This study investigates the factors influencing the imprinting performance of molecularly imprinted hybrids (MIHs) with various template/monomer associations and their corresponding adsorption ability for three bisphenol analogues, bisphenol A (BPA), 2,2'-bisphenol F (2BPF), and 4,4'-bisphenol F (4BPF). Styrene (St) and methacrylic acid (MAA) were selected as the primary functional monomers for template complexation. Compared with hydrophilic MAA monomers, hydrophobic St monomers were more favorable for BPA imprinting, despite the lower binding energy of π-π interactions compared to hydrogen bonds. However, St monomers were unsuitable for 4BPF imprinting, while 2BPF exhibited limited complexation with MAA monomers. Among the bisphenols, BPA demonstrated the strongest imprinting capability, leading MIHs to exhibit the highest imprinting factor (IF = 14-18), adsorption capacity (Qmax = 43.7-47.6 mg/g), binding affinity (KL = 4.52-6.74 L/mg, ΔHads° = -35.2 to -38.9 kJ/mol, and ΔSads° = -40.5 to -50.6 J mol-1 K-1), and selectivity over 2BPF and 4BPF (2.0-3.5). In contrast, 2BPF- and 4BPF-imprinted hybrids exhibited significantly lower adsorption capacities (Qmax = 19.4-26.7 mg/g) and binding affinities (KL = 1.22-4.35 L/mg) for their respective templates. In competitive adsorption systems, bisphenol rebinding followed the trend BPA > 2BPF > 4BPF, regardless of which template was used for imprinting. Based on NMR analysis, the superior structure-directing and competitive rebinding abilities of BPA are attributed to the restricted rotation of its two phenyl groups, p-OH groups, and additional -CH3 groups on the bridged carbon, which enhance π-π stacking, H-bond, CH-π, and hydrophobic interactions within the imprinted cavities. In contrast, the o-OH groups of 2BPF and the rotational phenyl groups of 4BPF hinder their imprinting and rebinding via H-bond and π-π interactions, respectively.

One-pot synthesized multifunctional Zn-MOF/HOF heterostructure sensor array assisted by machine learning for efficient capture, target discrimination and optosmart sensing of doxycycline analogs

The ideal multifunctional platform that combines the capabilities of effective capture, sensitive detection, and accurate identification of doxycycline analogs (DCs) remains a serious challenge for ensuring the environment and food security. This work constructs heterostructure Zn-MOF/HOF asynchronous response fluorescence sensor using a multicomponent one-pot method for high-efficiency capturing and sensitive detecting DCs. Metal nodes and functional groups in Zn-MOF/HOF provide sites for specifically recognizing and sensitizing DCs that induce asynchronous response with blue/green fluorescence emission. Fluorescence spectra of Zn-MOF/HOF show characteristic differences due to different spatial conformations and substituents of DCs. Machine learning-assisted Zn-MOF/HOF fluorescent sensing array accurately discriminates DCs with a high precision of 100 %. An exceptional adsorption capacity of DCs up to 569.00 mg/g realizes the effective pre-enrichment of DCs, improving the sensitivity of the Zn-MOF/HOF sensor. The limits of detection of the Zn-MOF/HOF sensor are as ultra-low as 2.2 nmol/L. Satisfactory recoveries of 91.78 %-113.16 % are obtained for detecting DCs in real-world water and food samples. A portable optosmart sensing system integrating the Zn-MOF/HOF sensor and smartphone realizes visual quantitation and on-site monitoring DCs. This work innovatively reveals the great potential of Zn-MOF/HOF heterostructure as a multifunctional platform for simultaneous capture, identification, and sensing of emerging contaminants.

Microplastics in groundwater: Environmental fate and possible interactions with coexisting contaminants

Microplastics (MPs) are emerging environmental pollutants which represent a serious threat to ecosystems and human health and have received significant attention from the global community. Currently, a growing number of studies have found the presence of MPs in groundwater. This study exhaustively reviewed varying degrees of recent publications in Web of Science database and investigated the characteristics of MPs (concentration, types, sizes and shapes) in groundwater ecosystems, their migration characteristics, and interactions with co-occurring contaminants. Results suggested that current global research on MPs in groundwater has primarily focused on countries such as India, South Korea, China, Italy and United States. Pollution levels of MPs in groundwater show significant variability, ranging from 0 to 6832 n/L. The predominant plastic polymer types include PP, PE, PS, PA, PET and PVC. The sources of MPs in groundwater are primarily classified as associated with natural processes and anthropogenic activities. The physical, chemical and biological properties can influence the migration of MPs into groundwater. Furthermore, MPs can act as carriers, interacting with co-occurring contaminants, thereby enhancing their migration and toxicity, potentially posing a threat to groundwater ecosystems and human health. Consequently, the major challenges and associated recommendations for forthcoming research on MPs in groundwater are proposed.

Short-term exposure to ciprofloxacin and microplastic leads to intrahepatic cholestasis, while long-term exposure decreases energy metabolism and increases the risk of obesity

Microplastics (MPs) and antibiotics are pervasive pollutants that may pose a risk to human health. Studies have shown that both MPs and antibiotics adversely affect lipid metabolism and increase the risk of obesity. However, it remains unclear whether combined exposure to these pollutants intensify the cumulative detrimental effect on obesity and metabolism. This study demonstrated the impact of exposure to polystyrene MPs (PS, 25 nm) and ciprofloxacin (CIP), both individually and combined, for 30 d and 90 d on the hepatic metabolism of male C57BL/6J mice. The results showed that mice exposed to PS and CIP for either 30 d or 90 d exhibited lipid metabolism disorders such as increased body weight, enlarged adipocytes, triglyceride accumulation in the liver, and higher HDL-C. Differentially expressed hepatic proteins were identified via proteomic analysis. The findings indicated that exposure for 30 d caused abnormal bile acid (BA) secretion in the liver and inhibited the BA secretion pathway, which resulted in intrahepatic cholestasis. Furthermore, exposure for 90 d resolved cholestasis and reduced the overall number of differentially expressed proteins. Intestinal pathology revealed more severe damage after exposure for 30 d, while 90 d exposure decreased the adverse effect. Combined CIP and PS exposure caused damage to the organism. However, the adaptive capacity of the organism during prolonged exposure mitigated the damage caused by both, but did not imply the complete eradication of adverse effects. This study found that 90 d exposure to PS and CIP resulted in weight gain, possibly due to changes in the gut flora and suppressed energy metabolism. These results indicated that simultaneous exposure to CIP and PS exacerbated the adverse impact on the liver, causing short-term intrahepatic cholestasis. Prolonged exposure reduced the energy metabolism in the body, exhibiting varied toxicity outcomes and mechanisms at different exposure durations. This study offers novel insights into the effect of MPs and antibiotic CIP exposure on metabolic abnormalities and provides a scientific basis for assessing these risks. It also emphasizes that the adverse effect resulting from 30 d (short-term) toxic exposure may not persist and that long-term chronic toxicity needs warrants.

Transport of microplastic-antibiotic co-contaminants in tidal zones

Microplastics (MPs) and antibiotics (ATs) are emerging contaminants with recognized negative effects on marine ecosystems. MPs can adsorb and transport ATs, posing combined toxic effects to marine organisms. Despite growing concerns, research remains limited on the MP-AT co-contaminants in tidal zones, which are home to numerous aquatic species and represent a particularly susceptible ecosystem. This study used polyethylene (PE) MPs and tetracycline (TC) to investigate the influence under various conditions, including sediment sizes, tidal cycles, and MP sizes, on the transport of MP-AT co-contaminants in tidal zones using a tidal cycle simulation system, which was designed to replicate the tidal dynamics and provide insights into the movement and behavior of contaminants. It was observed that MP-AT co-contaminants in tidal sediments exist in three distinct transport states. Smaller MP-AT co-contaminants (State 1) pass through sand pores and are widely distributed in the upper sediment layers, whereas larger MP-AT co-contaminants (State 2) concentrate in layers 1-5 due to size limitations. Agglomerated MP-AT co-contaminants (State 3), unable to pass through sand pores, accumulate at the bottom. Tidal cycles enhance MP-AT co-contaminant retention, while sand size (125-212 μm) limitedly affects their distribution. MP size played a crucial role, with larger MPs settling in layers 1-5 and smaller MPs remaining more dispersed. These findings emphasize the importance of MP size in affecting contaminant transport in tidal environments. Results from this research will contribute to the development of transport models and help predict the long-term environmental impact of MP-AT co-contaminants.

Manipulating Charge Dynamics in Carbon Nitride by Carbon Dot Doping for Efficient Photocatalysis

Graphitic carbon nitride (g-C3N4), a prominent metal-free semiconductor photocatalyst, faces limitations due to its high exciton binding energy. While significant efforts have been focused on optimizing charge-carrier processes, the interplay of exciton and free carrier in this system have received less attention. Herein, this density-functional theory (DFT) and time-dependent DFT calculations demonstrate that carbon dot-functionalized g-C3N4 (g-C3N4/CD), synthesized via a facile thermal polymerization, shifts the excited state from localized to charge transfer characteristics. The g-C3N4/CD exhibits reduced exciton binding energy from 41.0 to 24.6 meV, as shown by temperature-dependent photoluminescence spectroscopy. Particularly, g-C3N4/CD-10 (10 wt.% CD solution in precursors) achieves a 3-fold increase in the photodegradation rate (k = 0.020 min⁻¹) of an emerging environmental pollutant, levofloxacin (LEV), under 10 W LED light. Enhanced photocatalytic performances correlate with optimized band structure and efficient charge transport, as confirmed by photophysical and photoelectrochemical analyses. Although the excited state lifetime in g-C3N4/CD is slightly reduced compared to pristine g-C3N4, photocatalytic activity remains unaffected, underscoring the critical role of charge excited state in enhancing photocatalytic efficiency. This work offers insights onto the potential of manipulating charge transfer excited state dynamics for improved g-C3N4-based photocatalysis in environmental applications.

Establishing g-C3N4-Vn/FeIn2S4 heterostructure for in-situ H2O2 generation and activation to degrade tetracycline in photo-Fenton process under visible light

The heterogeneous photo-Fenton catalyst has attracted much interest in wastewater remediation applications. Herein, a heterostructure (CN-Vn/FIS) between ternary chalcogenide compound (FIS) and graphitic carbon nitride with nitrogen vacancies (CN-Vn) was synthesized via hydrothermal reaction to in-situ generate H2O2 under visible light and degrade tetracycline (TC) in water. CN-Vn/FIS could achieve as high as 98.5 % TC removal efficiency which maintained at 82.3 % in the fifth recycle, and was effective in the pH range of 2.6-9.0. The optical experiment suggested that CN-Vn/FIS demonstrates a broader light absorption edge as well as a low electron transfer energy barrier. Additionally, free radical trapping and EPR experiments proved that singlet oxygen (1O2) played a prominent role in the photo-Fenton process, while competitive reaction kinetic analysis calculated 1O2 contributed to 89.7 % TC degradation in CN-Vn/FIS system, which is nearly 3 times higher than 31.5 % in CN system. The results showed that CN-Vn/FIS created a one-step pathway to generate H2O2 without the aid of the intermediate free radical •O2-. This study illustrated an efficient and green TC degradation alternative through photo-Fenton process catalyzed by CN-Vn/FIS under visible light.

Less toxic combined microplastics exposure towards attached Chlorella sorokiniana in the presence of sulfamethoxazole while massive microalgal nitrous oxide emission under multiple stresses

Microalgae-based wastewater treatment could realize simultaneous nutrients recovery and CO2 sequestration. However, impacts of environmental microplastics (MPs) and antibiotic co-exposure on microalgal growth, nutrients removal, intracellular nitric oxide (NO) accumulation and subsequent nitrous oxide (N2O) emission are unclarified, which could greatly offset the CO2 sequestration benefit. To reveal the potential impacts of environmental concentrations of MPs and antibiotic co-exposure on microalgal greenhouse gas mitigation, this study investigated the effects of representative MPs (PE, PVC, PA), antibiotic sulfamethoxazole (SMX), and nitrite (NO2--N) in various combinations on attached Chlorella sorokiniana growth, nutrients removal, anti-oxidative responses, and N2O emission originated from intracellular NO build-up. Microalgal biofilm growth was more inhibited under 10 μg/L MPs than 100 μg/L SMX, and MPs+SMX co-exposure displayed toxicity antagonism while MPs+MPs co-exposure caused toxicity synergism (up to 66 % growth inhibition). Extracellular polysaccharides content correlated well with microalgal biofilm density under various stresses, while SMX involved stresses displayed chlorophyll a content reduction. Microalgal assimilation and MPs adsorption contributed to nutrients removal, and phosphorus removal displayed less variance among different stresses (residual phosphorus <0.5 mg/L) than nitrogen. Intracellular NO conversion to N2O almost doubled during the co-exposure processes, and N2O emission under NO2--N + PE+PVC co-exposure could offset the contribution of microalgal CO2 sequestration by as high as 176.2 %. Results of this study appealed for urgent concern regarding environmental MPs and antibiotic co-exposure on primary producers' growth characteristics and their greenhouse gas mitigation properties.

Impact of the hydrated functional zone on the adsorption of ciprofloxacin to microplastics under the influence of UV aging

The inevitable UV aging of microplastics (MPs) is one of the key factors affecting their interaction with antibiotics. In this study, polyethylene (PE) and polystyrene (PS) MPs were aged with UV irradiation. The adsorption isotherms and kinetics of ciprofloxacin (CIP) to virgin and aged MPs were investigated through various models, and the effects of pH on the adsorption amount were explored. Characterization revealed that the surfaces of aged MPs became rougher, and the hydrophilicity increased. These aged MPs were still in the early stage of aging on the basis of their carbonyl index (CI) (<0.2) and O/C (<0.04) values. The adsorption isotherms indicated that the adsorption mechanism of aged PE was different from that of virgin PE. Compared with virgin PE, the adsorption amount of aged PE increased by 87.80-95.45%, and the adsorption rate decreased by 65.52-80.74%. However, aging did not significantly affect the equilibrium adsorption amount or adsorption rate of aged PS. The external diffusion rate (Kext) (about 2.29-0.36 h-1) was almost 30 times greater than the internal diffusion rate (Kint) in the film-pore mass transfer (FPMT) model, indicating that CIP adsorption rate was dominated by external diffusion. A hydrated functional zone is thought to form around aged MPs, thus changing the adsorption mechanism and adsorption amount of aged PE. Therefore, more attention should be given to alterations in the hydrated functional zone in the early stage of MPs aging.

Environmental Health and Safety Implications of the Interplay Between Microplastics and the Residing Biofilm

The increasing prevalence of microplastics in the environment has raised concerns about their potential environmental and health implications. Biofilms readily colonize microplastics upon their entry into the environment, altering their surface characteristics. While most studies have explored how biofilms influence the adsorption and transportation of other contaminants by microplastics, the reciprocal interplay between microplastics and biofilms and the resulting ecological risks remain understudied. This review comprehensively reviews the impact of microplastic properties on biofilm formation and composition, including the microbial community structure. We then explore the dynamic interactions between microplastics and biofilms, examining how biofilms alter the physicochemical properties, migration, and deposition of microplastics. Furthermore, we emphasize the potential of biofilm-colonized microplastics to influence the environmental fate of other pollutants. Lastly, we discuss how biofilm-microplastic interactions may modify the bioavailability, biotoxicity, and potential health implications of microplastics.

Bacterium-Phage Symbiosis Facilitates the Enrichment of Bacterial Pathogens and Antibiotic-Resistant Bacteria in the Plastisphere

The plastisphere, defined as the ecological niche for microbial colonization of plastic debris, has been recognized as a hotspot of pathogenic and antibiotic-resistant bacteria. However, the interactions between bacteria and phages facilitated by the plastisphere, as well as their impact on microbial risks to public health, remain unclear. Here, we analyzed public metagenomic data from 180 plastisphere and environmental samples, stemming from four different habitats and two plastic types (biodegradable and nonbiodegradable plastics) and obtained 611 nonredundant metagenome-assembled genomes (MAGs) and 4061 nonredundant phage contigs. The plastisphere phage community exhibited decreased diversity and virulent proportion compared to those found in environments. Indexes of phage-host interaction networks indicated significant associations of phages with pathogenic and antibiotic-resistant bacteria (ARB), particularly for biodegradable plastics. Known phage-encoded auxiliary metabolic genes (AMGs) were involved in nutrient metabolism, antibiotic production, quorum sensing, and biofilm formation in the plastisphere, which contributed to enhanced competition and survival of pathogens and ARB hosts. Phages also carried transcriptionally active virulence factor genes (VFGs) and antibiotic resistance genes (ARGs), and could mediate their horizontal transfer in microbial communities. Overall, these discoveries suggest that plastisphere phages form symbiotic relationships with their hosts, and that phages encoding AMGs and mediating horizontal gene transfer (HGT) could increase the source of pathogens and antibiotic resistance from the plastisphere.

Adsorption behavior of commercial biodegradable plastics towards pollutants during the biodegradation process: Taking starch-based biodegradable microplastics, oxytetracycline and Cu (II) as examples

With the widespread use of biodegradable plastic bags, their potential environmental risks need further assessment. This study focused on commercial starch-based blended biodegradable microplastics (70% Poly(butylene adipate-co-terephthalate) (PBAT)+5% Poly(lactic acid) (PLA)+20% Thermoplastic starch (TPS), PPT MPs) to investigate their adsorption behaviors towards Cu(II) and oxytetracycline (OTC) under microbial colonization and biodegradation. Post-biodegradation, the hydroxyl (-OH) peak intensity of starch in PPT significantly decreased, while carbonyl (C=O) peaks of PBAT and PLA broadened, with O/C ratio rising from 14.65% to 35.82%. The starch's degradation in PPT altered its thermal properties. Microbial colonization on PPT (B-PPT) enhanced Cu(II) and OTC adsorption, while biodegradation (D-PPT) reduced their adsorption. Reduced surface carbonyl and hydroxyl groups, alongside increased crystallinity, diminished D-PPT's Cu(II) adsorption. While OTC adsorption, driven by hydrophobic partitioning, was less affected by biodegradation. In the binary pollutant system, the Cu(II) and OTC adsorption of D-PPT increased by 20.27% and 8.63 times, respectively; B-PPT showed decreased adsorption of both. Coexisting organic matter and pH significantly affected PPT's adsorption behavior by altering Cu(II) and OTC speciation, and influencing adsorption competition, hydrogen bonding and bridging effects. This study is the first to explore biodegradation impacts of commercial starch-based microplastics on typical heavy metals and antibiotics adsorption, providing important theoretical insights for understanding their environmental risks.

Microplastics as adsorbent for Pb2+ and Cd2+: A comparative study of polypropylene, polyvinyl chloride, high-density polyethylene, and low-density polyethylene

Microplastics (MPs) in aquatic environments adsorb heavy metals, thereby posing potential environmental risks. However, further research is needed to elucidate the adsorption behavior of different types of MPs for various heavy metals. The aim of this study was to characterize four types of MPs: polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). Moreover, their Pb2+ and Cd2+ adsorption properties were determined to investigate the differences in their capacity to function as heavy metal adsorbents. MPs were characterized via scanning electron microscopy (SEM) using energy dispersive X-ray spectrometer (EDS), Brunauer-Emmett-Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR). Adsorption experiment data were analyzed using the Langmuir and Freundlich isotherm models to evaluate the adsorption capacity of the MPs. Based on the results of the adsorption isotherm models and 2D-COS FTIR, the presence of oxygen-containing functional groups, including hydroxyl, carbonyl, and carboxyl groups influences the adsorption process of Pb2+ and Cd2+ onto PP and PVC, with the maximum adsorption capacities (Qm) being 0.759 mg/g and 0.495 mg/g, respectively. Combination of the adsorption isotherm data and characteristics of MPs revealed that the following order of adsorption efficiencies of MPs for each heavy metal: PP > LDPE > PVC > HDPE for Pb2+ and PP > PVC > LDPE > HDPE for Cd2+. The results of this study suggest that MPs, particularly PP and PVC, may serve as vectors for heavy metal transport in aquatic environments, highlighting the need for further research to assess their environmental impact.

Sorption behavior of oxytetracycline on microplastics and the influence of environmental factors in groundwater: Experimental investigation and molecular dynamics simulation

Microplastics (MPs) and antibiotics can enter groundwater through the interaction of soil and surface water, and MPs as carriers of antibiotics can promote the migration of antibiotics and thus generate more serious ecological risks. Therefore, this paper used experimental and molecular dynamics (MD) simulation methods to investigate the sorption between four common types of MPs in groundwater, namely polyamide (PA), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene (PE), and oxytetracycline (OTC) with high detection rate in groundwater. Additionally, the impact of environmental factors on sorption was examined. The sorption kinetics of the four types of MPs followed the pseudo-second-order kinetics model, and the sorption isotherms of OTC on PA, PE, and PVC were highly linear, suggesting that the electrostatic interaction was the main sorption mechanism. Both experimental and simulation results indicated that PA had the highest affinity for OTC, due to the effect of the formation of hydrogen bonding between the amide groups of PA and OTC. The primary way pH affected sorption was by altering the form in which OTC exists. The effects of the representative substances of protein-like component (bovine serum albumin) and humus-like component (humic acid) in dissolved organic matter varied but were generally inhibitory. Ions could influence the sorption process by competitive sorption or forming complexes with the OTC.

Recent advances and factors affecting the adsorption of nano/microplastics by magnetic biochar

The increase in nano/microplastics (NPs/MPs) from various everyday products entering aquatic environments highlights the urgent need to develop mitigation strategies. Biochar (BC), known for its excellent adsorption capabilities, can effectively target various harmful organic and inorganic pollutants. However, traditional methods involving powdered BC necessitate centrifugation and filtration, which can lead to the desorption of pollutants and subsequent secondary pollution. Magnetic biochar (MBC) offers a solution that facilitates straightforward and rapid separation from water through magnetic techniques. This review provides the latest insights into the progress made in MBC applications for the adsorption of NPs/MPs. This review further discusses how external factors such as pH, ionic strength, temperature, competing ions, dissolved organic matter, aging time, and particle size impact the MBC adsorption efficiency of MPs. The use of machine learning (ML) for optimizing the design and properties of BC materials is also briefly addressed. Finally, this review addresses existing challenges and future research directions aimed at improving the large-scale application of MBC for NPs/MPs removal.

Short-term and long-term effects of microplastics and organic UV-filters on the invertebrate model species Daphnia magna

There is an ongoing debate regarding the role of microplastics (MPs) in enhancing the effects of various chemical compounds, highlighting the need for more detailed analyses. In this study, neonates of the water flea (Daphnia magna) were exposed to polystyrene MPs (PS-MPs; 3 µm; exposure concentration, 1.25 mg/L), a mixture of seven organic UV-filters (avobenzone, ethylhexyl triazone, homosalate, iscotrizinol, octinoxate, octisalate, and octocrylene; each at a low environmental concentration of 200 ng/L), or the combination of both pollutants for 3, 7, or 21 days. Results showed that PS-MPs alone decreased the body size of daphnids, while all treatments increased heart rate by the end of the 21-day exposure. On days 3 and 21, both PS-MPs and PS-MPs + UV-filters reduced swimming speed and total distance travelled. Additionally, PS-MPs increased the time of the first egg production, but decreased the egg number in the first production, total egg number, maximum egg number, and total neonate number during the 21-day treatment. Similarly, UV-filters or the combined pollutants increased the time of the first egg production and decreased the total neonate number. All treatments increased multixenobiotic resistance activity on days 3 and 7, while only UV-filters elevated CYP450 activity on day 3. PS-MPs or combined pollutants increased GST activity during early exposure but showed no effect on day 21. CAT activity was also affected by treatments in a time-dependent manner. These findings demonstrate that chronic exposure to PS-MPs and UV-filters, applied individually or in combination at a low environmental concentration, moderately impacts development, heart rate, and swimming activity in D. magna, while significantly altering reproduction and key cellular functions such as membrane transport activity, metabolism, and antioxidant defense. Co-exposure did not reveal a clear pattern of synergism or antagonism, suggesting that joint toxicity risks of these xenobiotics typically emerge at concentrations higher than low environmental levels. Future studies should explore potential interactions more thoroughly and assess transgenerational effects on reproduction and cellular defense pathways.

Microplastics Exacerbated Conjugative Transfer of Antibiotic Resistance Genes during Ultraviolet Disinfection: Highlighting Difference between Conventional and Biodegradable Ones

Microplastics (MPs) have been confirmed as a hotspot for antibiotic resistance genes (ARGs) in wastewater. However, the impact of MPs on the transfer of ARGs in wastewater treatment remains unclear. This study investigated the roles and mechanisms of conventional (polystyrene, PS) and biodegradable (polylactic acid, PLA) MPs in the conjugative transfer of ARGs during ultraviolet disinfection. The results showed that MPs significantly facilitated the conjugative transfer of ARGs compared with individual ultraviolet disinfection, and PSMPs exhibited higher facilitation than PLAMPs. The facilitation effects were attributed to light shielding and the production of reactive oxygen species (ROS) and nanoplastics from ultraviolet irradiation of MPs. The light shielding of MPs protected the bacteria and ARGs from ultraviolet inactivation. More importantly, ROS and nanoplastics generated from irradiated MPs induced intracellular oxidative stress on bacteria and further increased the cell membrane permeability and intercellular contact, ultimately enhancing the ARG exchange. The greater fragmentation of PSMPs than PLAMPs resulted in a higher intracellular oxidative stress and a stronger enhancement. This study highlights the concerns of conventional and biodegradable MPs associated with the transfer of ARGs during wastewater treatment, which provides new insights into the combined risks of MPs and ARGs in the environment.

Microplastics enhance the adsorption capacity of zinc oxide nanoparticles: Interactive mechanisms and influence factors

Microplastics (MPs) are of particular concern due to their ubiquitous occurrence and propensity to interact and concentrate various waterborne contaminants from aqueous surroundings. Studies on the interaction and joint toxicity of MPs on engineered nanoparticles (ENPs) are exhaustive, but limited research on the effect of MPs on the properties of ENPs in multi-solute systems. Here, the effect of MPs on adsorption ability of ENPs to antibiotics was investigated for the first time. The results demonstrated that MPs enhanced the adsorption affinity of ENPs to antibiotics and MPs before and after aging showed different effects on ENPs. Aged polyamide prevented aggregation of ZnONPs by introducing negative charges, whereas virgin polyamide affected ZnONPs with the help of electrostatic attraction. FT-IR and XPS analyses were used to probe the physicochemical interactions between ENPs and MPs. The results showed no chemical interaction and electrostatic interaction was the dominant force between them. Furthermore, the adsorption rate of antibiotics positively correlated with pH and humic acid but exhibited a negative correlation with ionic strength. Our study highlights that ENPs are highly capable of accumulating and transporting antibiotics in the presence of MPs, which could result in a widespread distribution of antibiotics and an expansion of their environmental risks and toxic effects on biota. It also improves our understanding of the mutual interaction of various co-existing contaminants in aqueous environments.

Mechanism of microplastics promoting sulfamethoxazole biodegradation in activated sludge as revealed by DNA-stable isotope probing

Microplastics (MPs) often coexist with sulfonamide antibiotics (SAs) in the activated sludge of wastewater treatment plants (WWTPs). Microbial degradation is a crucial pathway for SAs removal in the activated sludge, though its response to MPs still yet to be disclosed. Here, we combined DNA-stable isotope probing (DNA-SIP), PICRUSt and MENA techniques to explore the impact of MPs on the microbial biodegradation of sulfamethoxazole (SMX) in the activated sludge. DNA-SIP revealed 20 genera were responsible for the SMX degradation in the activated sludge, with 13 of these genera being firstly linked with sulfonamide biodegradation. The potential SMX-degrading bacteria showed complex synergistic interaction with the other microbes. Eight degradation pathways were constructed based on the nine identified SMX-related degradation genes. MPs addition enhanced the SMX biodegradation by altering the structure of degrading microbes, increasing their relative abundance and promoting the synergistic interactions between potential SMX-degrading bacteria and other microbes in activated sludge. Besides, genes related to abundant energy production and biofilm formation were involved in SMX degradation in the activated sludge with MPs. Our study reveals the MPs influence on SMX biodegradation in activated sludge, and disclose the potential underlying mechanisms, which will benefit the regulation on antibiotic removal in WWTPs.

Combined pollution of tetracyclines and microplastics in the aquatic environment: Insights into the occurrence, interaction mechanisms and effects

Tetracyclines, a widely used class of antibiotics, and synthetic plastic products are both prevalent in the environment. When released into water bodies, these pollutants can pose significant risks due to their daily influx into aquatic ecosystems. Microplastics can adsorb tetracyclines, acting as a transport vector that enhances their impact on aquatic species. Understanding the co-exposure effects of microplastics and tetracyclines is crucial. This review comprehensively examines the occurrence and distribution of microplastics and tetracyclines across various environmental contexts. The interactions between these two contaminants are primarily driven by electrostatic interactions, hydrophobic effects, hydrogen bonding, π-π interactions, and others. Factors such as the presence of heavy metals, ions, and dissolved organic matter can influence the adsorption and desorption of tetracyclines onto microplastics. The stability of microplastic-tetracycline complexes is highly dependent on pH conditions. The combined pollution tetracyclines and microplastics leads to negative impacts on marine species. Future research should focus on understanding the adsorption behavior of tetracyclines on microplastics and developing effective treatment techniques for these contaminants in aquatic environments.

Multi-omics analysis reveals interactions between host and microbes in Bama miniature pigs during weaning

Introduction

There are complex interactions between host and gut microbes during weaning, many of the mechanisms are not yet fully understood. Previous research mainly focuses on commercial pigs, whereas limited information has been known about the host and gut microbe interactions in miniature pigs.

Methods

To address the issue in Bama miniature piglets that were weaned 30 days after birth, we collected samples on days 25 and 36 for metabolomics, transcriptomics, and microgenomics analysis.

Results and discussion

The average daily weight gain of piglets during weaning was only 58.1% and 40.6% of that during 0-25 days and 36-60 days. Metabolomic results identified 61 significantly different metabolites (SDMs), of which, the most significantly increased and decreased SDMs after weaning were ectoine and taurocholate, respectively, indicating the occurrence of inflammation. Metagenomic analysis identified 30 significantly different microbes before and after weaning. Bacteria related to decreasing intestinal inflammation, such as Megasphaera, Alistipes and Bifidobacterium, were enriched before weaning. While bacteria related to infection such as Chlamydia, Clostridium, Clostridioides, and Blautia were enriched after weaning. The carbohydrate enzymes CBM91, CBM13, GH51_1, and GH94 increase after weaning, which may contribute to the digestion of complex plant fibers. Furthermore, we found the composition of antibiotic resistance genes (ARGs) changed during weaning. Transcriptomic analysis identified 147 significantly differentially expressed genes (DEGs). The upregulated genes after weaning were enriched in immune response categories, whereas downregulated genes were enriched in protein degradation. Combining multi-omics data, we identified significant positive correlations between gene MZB1, genera Alistipes and metabolite stachydrine, which involve anti-inflammatory functions. The reduced abundance of bacteria Dialister after weaning had strong correlations with the decreased 2-AGPE metabolite and the downregulated expression of RHBDF1 gene. Altogether, the multi-omics study reflects dietary changes and gut inflammation during weaning, highlighting complex interactions between gut microbes, host genes and metabolites."

Phototransformation and photoreactivity of MPs-DOM in aqueous environment: Key role of MPs structure decoded by optical and molecular signatures

The dissolved organic matter (DOM) derived from microplastics (MPs-DOM) can be one of the photoactive components in DOM. However, information on the properties and photoreactivity of MPs-DOM during phototransformation is limited. Here, we investigated the properties and photoreactivity of MPs-DOM from polyolefins (MPs-DOM-POs), MPs-DOM derived from benzene-containing polymers (MPs-DOM-BCPs), and Suwannee River natural organic matter (SR-NOM), during a 168-hour phototransformation. After phototransformation, all examined types of DOM exhibit a decrease in concentration and molecular weight. Notably, MPs-DOM-POs display increased aromaticity and saturation, while MPs-DOM-BCPs and SR-NOM show reduced aromaticity and saturation. MPs-DOM-POs present higher steady-state concentrations of •OH but much lower steady-state concentrations of 1O2 than those of MPs-DOM-BCPs. In comparison, MPs-DOM produce more •OH but less 1O2 than SR-NOM. This study proposes that the diversification of aliphatic C─H bonds (arylation and carbonylation) by reactive intermediates (especially •OH) is the main pathway for MPs-DOM-POs phototransformation for the first time. On the other hand, the cleavage on the aromatic carboxylic acids by reactive intermediates (especially 1O2) is the main mechanism for MPs-DOM-BCPs and SR-NOM phototransformation. Our findings provide new insights into the phototransformation and photoreactivity of MPs-DOM and help to understand the potential risks of MPs in aqueous environment.

Micro/nano plastics inhibit the formation of barium sulfate scale on metal surface

Mineral scale (scale) is the crystalline inorganic precipitate from aqueous solution. Scale formation in pipelines has long been a challenge in various industrial systems. Micro/nano plastics (MNPs) have the potential to strongly influence scale formation process. However, comprehensive studies and mechanistic understanding of the interactions between MNPs and scales remain significantly underexplored. To fill this gap, we firstly adopted quartz crystal microbalance with dissipation (QCM-D) technology to monitor the in situ formation of barium sulfate (BaSO4) (0.001 M, saturation index 2.5) scale influenced by MNPs on metal surfaces. Microplastic (MP) (5 µm)-loaded surface exhibits hydrophobicity (contact angle > 123.1º), which reduces the rate of scale formation (90.86 ± 11.01 (ng cm-2 min-1)). Electrostatic repulsion impeded crystal growth while ion adsorption has a limited effect. Experiments on BaSO4 formation on metal pipes loaded with foam packaging debris were conducted over 30 days, and similar inhibition results were obtained. This study highlights the important role of MNPs in controlling heterogeneous nucleation and crystal growth of scale on metal surfaces, providing valuable insights for both MNPs and scale research.

Spontaneous interactions between typical antibiotics and soil enzyme: Insights from multi-spectroscopic approaches, XPS technology, molecular modeling, and joint toxic actions

A large amount of antibiotics enters the soil environment and accumulates therein as individuals and mixtures, threatening the soil safety. However, there is little information regarding the influence of single and mixed antibiotics on key soil proteins at molecular level. In this study, setting sulfadiazine (SD) and tetracycline hydrochloride (TC) as the representative antibiotics, the interactions between these agents and α-amylase (an important hydrolase in soil carbon cycle) were investigated through multi-spectroscopic approaches, X-ray photoelectron spectrometry, and molecular modeling. It was found that both SD and TC spontaneously bound to α-amylase with 1:1 stoichiometry mainly via forming stable chemical bonds. The interactions altered the polarity of aromatic amino acids, protein backbone, secondary structure, hydrophobicity and activity of α-amylase. The SD-TC mixtures were designed based on the direct equipartition ray to comprehensively characterize the possible concentration distribution, and interactive effects indicated that the mixtures antagonistically impacted α-amylase. These findings reveal the binding characteristics between α-amylase and typical antibiotics, which probably influence the ecological functions of α-amylase in soil. This study clarifies the potential harm of antibiotics on soil functional enzyme, which is significant for the environmental risk assessment of antibiotics and their mixtures.

Combined contamination of tire and road wear microplastics with heavy metals in expressway tunnels: occurrence characteristics and risk assessment

Tire and road wear microplastics (TRWMPs), as an important type of microplastics, have attracted increasing attention. However, current studies on their contamination within expressway tunnels remain limited. Therefore, we investigated the occurrence characteristics of TRWMPs in dusts from various tunnels, and combined contamination with heavy metals (HMs). The results showed that the abundance of TRWMPs in expressway tunnel dust (53,778 n/kg) was much higher than that sampled from other land use types (1360-4960 n/kg) in the same region. A large amount of polyamide was released into the environment along with wear particles from the vehicles. Also, the abundance of TRWMPs inside tunnels was greater than outside, and the proportion of large-size TRWMPs was higher inside tunnels. TRWMPs was symmetrically distributed with respect to the center of expressway tunnel. The pollution load index (PLI) and ecological risk index (H) indicated that study area was heavily contaminated with TRWMPs. There was a significant positive correlation between the abundance of TRWMPs and concentration of Cr (p < 0.01) in dust, and their risk assessment and health risk fluctuations were almost identical. Thus, the study is of great significance for elucidating the synergistic contamination and potential risk of TRWMPs and HMs in expressway tunnels.

A new holistic perspective to assess the ecological risk of microplastics: A case study in Baiyangdian Basin, China

By integrating probabilistic ecological risk assessment with the overall risk index method, which considers the multidimensional characteristics of the microplastome, the ecological risks of microplastic pollution were assessed more comprehensively. This study took the Baiyangdian Basin as an example to address the limitations of current risk assessment methods that rely on concentration data or the individual risk of microplastics. Using an exponential regression model, the acute and chronic ecological risk thresholds for the overall risk index method were determined to be 0.43 and 0.30, respectively. The acute and chronic ecological risks of the microplastome occupied 61 % and 79 % of the Baiyangdian Wetland and 0 % and 14 % of the Fu River, while the Xiaoyi River did not exhibit risk during the rainy season. Results indicated that intense human activities, poor hydrodynamics, low settling velocity and high levels of environmental chemical pollutants jointly contributed to the high risk of the microplastome in water bodies. Compared with the probabilistic ecological risk assessment method (risk characterization ratio), there was a significant difference in the area of acute and chronic ecological risks caused by the microplastome in the Baiyangdian Basin when using the overall risk index method. This proved that considering only concentration cannot truly reflect the toxicity of microplastics to aquatic organisms.

Distribution characteristics and relationship of microplastics, phthalate esters, and bisphenol A in the Beiyun River basin of Beijing

Urban rivers are closely related to human life, and due to the widespread use of plastic products, rivers have become important carriers of pollutants such as microplastics (MP), phthalate esters (PAEs), and bisphenol A (BPA). However, our understanding of the distribution characteristics and relationships of MP, PAEs, and BPA in rivers is limited. In this study, MP, six PAEs and BPA were detected in the water and sediments of the Beiyun River basin. Polyvinyl chloride (PVC) was the most abundant type of microplastic, while di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) were the most abundant PAEs. MP, PAEs, and BPA in both water and sediment showed positive correlations, with stronger correlations and higher pollution levels in sediment than in water. The tendency for PAE congeners to partition into sediments increased with a higher octanol-water partition coefficient (Kow). There was a significant positive correlation between the distribution tendency of ∑6PAEs and TOC in sediments with a pearson correlation coefficient of 0.717. Rivers with more frequent human activities and higher levels of urbanization in the vicinity had a higher abundance of various pollutants and a greater diversity of MP types.

Microplastic and associated emerging contaminants in marine fish from the South China Sea: Exposure and human risks

Microplastics can act as vectors of chemical contaminants in aquatic environments, but the extent to which this phenomenon contributes to chemical exposure in marine organisms remains poorly understood. We investigated the occurrence of microplastics and emerging contaminants (ECs), including antibiotics and per- and polyfluoroalkyl substances (PFAS) in 14 marine fish species. Microplastics were detected in all marine fish species, mainly in the gastrointestinal tract. Fluoroquinolones and tetracyclines were the dominant antibiotics in fish muscles with maximum concentrations of 24.84 and 26.95 ng g-1 ww, while perfluorooctanesulfonic acid (PFOS, 0.039-0.95 ng g-1 ww) was the dominant component in the PFAS profile. Fish with more microplastics had significantly higher concentrations of fluoroquinolones and perfluoroalkyl acids than fish with less microplastics (p < 0.05), but the correlation was not observed in other chemicals. Structural equation modeling revealed the contribution of microplastics in fish on the level of ECs contamination. The health quotient value indicated the low health risk of single compounds via fish consumption to humans; however, the combined risk of microplastics and ECs still needs to be considered. This work highlights the link between microplastics with associated ECs ingested by aquatic organisms and the human health risk of consuming polluted seafood.

MRI-based microplastic tracking in vivo and targeted toxicity analysis

Microplastics (MPs) as an emerging pollutant have raised significant concerns in environmental health. However, elucidating the distribution of MPs in living organisms remains challenging due to their trace residue and tough detection problems. In this study, a novel magnetic resonance imaging (MRI)-based tracking method was employed to monitor functionalized MPs biodistribution in vivo. Our results identified that the liver is the primary accumulation site of polystyrene microplastics (PS-MPs) in biological systems through continuous in vivo monitoring spanning 21 days. Biochemical tests were performed to assess the toxicological effects of functionalized MPs on the liver tissue, revealing hepatocyte death, inflammatory cell infiltration, and alterations in alkaline phosphatase levels. Notably, positively charged MPs exhibited more severe effects. A combined metabolomics-proteomics analysis further revealed that PS-MPs interfered with hepatic metabolic pathways, particularly bile secretion and ABC transporters. Overall, this study effectively assessed the distribution of functionalized MPs in vivo utilizing MRI technology, validated toxicity in targeted organ, and conducted an in-depth study on underlying biotoxicity mechanism. These findings offer crucial scientific insights into the potential impact of MPs in the actual environment on human health.

Uptake, removal and trophic transfer of fluorescent polyethylene microplastics by freshwater model organisms: the impact of particle size and food availability

As an emerging contaminant, microplastics (MPs) are widely distributed in freshwater ecosystems and pose potential threats to aquatic organisms, attracting significant attention from both the scientific community and the general public. However, there is still uncertainty regarding the mechanisms of MPs transfer within aquatic biota and how particle size and food availability influence their transport patterns. In this study, zebrafish (Danio rerio) were selected as a model organism to investigate the uptake and elimination of fluorescent polyethylene (PE) MPs under different exposure scenarios (waterborne or trophic transfer, with or without food) and varying particle sizes (ranging from 10-300 μm at concentrations of 0.1, 2, and 300 mg/L). Additionally, water fleas (Daphnia magna) were provided as prey for the fish. The dynamic accumulation of PE-MPs sized between 10-20 μm at a concentration of 25 mg/L by daphnia was also determined along with its impact on animal feeding behavior. The results demonstrated that both organisms were capable of ingesting PE-MPs during exposures lasting up to 24 hours for daphnia and up to 72 hours for zebrafish. Furthermore, rapid elimination rates were observed within just 30 minutes for daphnia and between 6-12 hours for zebrafish. The presence of food reduced MPs uptake and removal by daphnia but significantly increased MP elimination by fish. Zebrafish showed a preference for ingesting larger-sized MPs that they could easily recognize; however, trophic transfer from daphnia to fish was found to be the primary route of ingestion specifically for PE-MPs sized between 10-20 μm. The findings suggest that while fish directly ingest fewer invisible MPs from the water column, they still accumulate these particles through predation on contaminated prey organisms. Therefore, it is imperative to prioritize the ecological risks associated with the transfer of MPs from zooplankton to fish.

Selection of engineered degradation method to remove microplastics from aquatic environments

Microplastics (MPs) in the aquatic environment are difficult to degrade naturally due to their hydrophobicity and structure. A variety of engineered degradation methods were developed to treat MPs contamination in the aquatic environment. Current reviews of MPs degradation methods only provided an inventory but lacked systematic comparisons and application recommendations. However, selecting suitable degradation methods for different types of MPs contamination may be more effective. This work examined the present engineered degradation methods for MPs in the aquatic environment. They were categorized into chemical degradation, biodegradation, thermal degradation and photodegradation. These degradation methods were systematically summarized in terms of degradation efficiency, technical limitations and production of environmental hazards. Also, the potential influences of different environmental factors and media on degradation were analyzed, and the selection of degradation methods were suggested from the perspectives of contamination types and degradation mechanisms. Finally, the development trend and challenges for studying MPs engineered degradation were proposed. This work will contribute to a better selection of customized degradation methods for different types of MPs contamination scenarios in aquatic environments.

Microplastic and antibiotics in waters: Interactions and environmental risks

Antibiotics (ATs) are ubiquitously detected in natural waters worldwide, and their tendency to co-migrate with microplastics (MPs) post-adsorption leads to heightened environmental risk. Research on the adsorption of ATs on MPs and their subsequent effects on the environmental risks is gaining significant attention globally. This adsorption process predominantly occurs through hydrophobic forces, hydrogen bonds, and electrostatic interactions and is influenced by various environmental factors. The interaction between MPs and ATs exhibited varying degrees of efficiency across different pH levels and ionic strengths. Furthermore, this paper outlines the environmental risks associated with the co-presence of MPs and ATs in aquatic environments, emphasizing the potential effect of MPs on the distribution of antibiotic resistance genes (ARGs) and related environmental risks. The potential hazards posed by MPs and ATs in aquatic systems warrant serious consideration. Future research should concentrate on the adsorption of ATs/ARGs on MPs under real environmental conditions, horizontal gene transfer on MPs, as well as biofilm formation and agglomeration behavior on MPs that needs to be emphasized.

Co-exposure to microplastics and soil pollutants significantly exacerbates toxicity to crops: Insights from a global meta and machine-learning analysis

Environmental contamination of microplastics (MPs) is ubiquitous worldwide, and co-contamination of arable soils with MPs and other pollutants is of increasing concern, and may lead to unexpected consequences on crop production. However, the overall implications of this combined effect, whether beneficial or detrimental, remain a subject of current debate. Here, we conducted a global meta and machine-learning analysis to evaluate the effects of co-exposure to MPs and other pollutants on crops, utilizing 3346 biological endpoints derived from 68 different studies. Overall, compared with control groups that only exposure to conventional soil contaminants, co-exposure significantly exacerbated toxicity to crops, particularly with MPs intensifying adverse effects on crop morphology, oxidative damage, and photosynthetic efficiency. Interestingly, our analysis demonstrated a significant reduction in the accumulation of pollutants in the crop due to the presence of MPs. In addition, the results revealed that potential adverse effects were primarily associated with crop species, MPs mass concentration, and exposure duration. Our study reaffirms the substantial consequences of MPs as emerging pollutants on crops within the context of integrated pollution, providing novel insights into improving sustainability in agro-ecosystems.

Selective elimination of organic pollutants and analysis of effects and novel mechanisms of aged microplastics on wavelength-dependent UV-LED/H2O2 system

The selective removal of organic pollutants and potential impact of aged microplastics (MPs) as emerging pollutants in wavelength-dependent UV-LED/H2O2 system are not fully understood. This study found that cefalexin (CFX) degradation efficiency in UV-LED alone system was highly correlated with its UV molar absorbance (R2=0.994), while in UV-LED/H2O2 system, it was correlated with ·OH yield (R2=0.991) across various wavelengths. Quantitative structure-activity relationship (QSAR) analysis showed selective degradation of six pollutants based on their e--donating capabilities (R2=0.748-0.916). The coexistence of aged MPs, introducing C-O/C=O groups and rearranging their surface e-, potentially affected the elimination efficiency of CFX. Aged polystyrene (PS) decreased the degradation efficiency of CFX by shorting the O-O bond length (lO-O) in H2O2 and capturing e- from H2O2, whereas aged polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC) had negligible effects as the lO-O elongation balanced the e--donating effect of H2O2. Additionally, phenol released from aged PS, with strong nucleophilicity, competing with CFX for ·OH, further decreasing CFX degradation efficiency. This study provides valuable insights into organic pollutant selective removal and reveals a novel inhibitory mechanism of aged PS on the performance of UV-LED/H2O2 technology.

Ecological criteria for antibiotics in aquatic environments based on species sensitivity distribution

Due to the substantial production and use of antibiotics, they inevitably remain in aquatic environments, posing a serious threat to aquatic ecosystems. However, there are currently no criteria of antibiotics for ecological risk in the water environment. In the present study, three types of antibiotics (tetracyclines, sulfonamides and quinolones) that are often detected in water environments were investigated. Toxicity data regarding bacteria, algae, plants, invertebrates and vertebrates were selected, and the species sensitivity distribution was used to obtain the ecological risk criteria of antibiotics to aquatic organisms. Animals are the least sensitive to antibiotics. The overall toxicity of antibiotics is most sensitive to bacteria and cyanobacteria, followed by green algae and plants. The recommended ecological criteria for tetracyclines, quinolones, and sulfonamides are 22, 17, and 94 μg/L, respectively. Ofloxacin needs to be used with caution because it has a small acute predicted no-effect concentration (PNEC) of 0.6 μg/L. The ecological risk criterion for chronic toxicity of total antibiotics was determined to be 1.4 μg/L. The PNECs measured for the quinolone, tetracycline, and sulfonamide antibiotics were 0.5, 2.2, and 2.4 μg/L, respectively. Norfloxacin had the highest chronic toxicity zone of 353, indicating that chronic poisoning is most likely to occur. Moreover, there was an exponential correlation between acute PNEC and chronic PNEC. In addition, a quantitative structure-activity relationship model was constructed for acute ecological risk criteria of antibiotics to aquatic organisms. These findings can expand the ecological risk threshold data on the effects of antibiotics on aquatic organisms, and provide a theoretical basis for the environmental risk assessment of antibiotics.

Polystyrene microplastics as carriers for nano-hydroxyapatite particles: Impact of surface functionalization and mechanistic insights

The potential of microplastics (MPs) to act as carriers for contaminants or engineered nanomaterials is of rising concern. However, directly determining the vector effect of polystyrene (PS) MPs towards nano-hydroxyapatite (nHAP) particles, a typical nano phosphorus fertilizer and soil remediation material, has been rarely studied. In this study, the interaction of differentially surface functionalized PS MPs with nHAP were investigated through batch experiments under different solution chemistry conditions. The results demonstrated that nHAP had the highest attachment/adsorption affinity onto carboxyl-functionalized PS, followed by bare PS and amino-functionalized PS under near-neutral pH conditions. Adsorption of nHAP exhibited a strong pH-dependent behavior with PS MPs, increasing under acidic-neutral pH (3-7) and decreasing at higher pH values. The presence of humic acid and NaCl hindered the adsorption of nHAP onto MPs. Scanning electron microscopy observations revealed a rod-like morphology for adsorbed nHAP, which was randomly distributed on MPs surface. Surface complexation and cation-π interaction were mainly responsible for the adsorption of nHAP as revealed by multiple spectroscopic analyses. These results provide mechanistic insights into nHAP-PS interactions and expound the effect of surface functionalization of PS on binding mechanisms, and thus bring important clues for better understanding the vector effects of MPs towards nanoparticles.

Decreased Sulfamethoxazole Uptake in Lettuce (Lactuca sativa L.) due to Transpiration Inhibition by Polypropylene Microplastics

Microplastics and antibiotics are emerging contaminants in agricultural soil that can have negative effects on crops. However, limited research has been conducted on the effects of the polypropylene (PP) microplastic and sulfamethoxazole (SMX) co-exposure on crops, specifically regarding the impact of PP microplastics on SMX uptake and transport in crops. In this study, hydroponic experiments were carried out using lettuce (Lactuca sativa L.), PP microplastics (1.0 g L-1), and SMX (0.5 mg L-1 or 2.5 mg L-1) to investigate the individual and co-exposure effects of PP microplastics and SMX on Lettuce growth, explore the uptake and translocation of SMX in lettuce and elucidate the underlying mechanism of PP microplastic impact on SMX uptake. Results demonstrated that co-exposure to 1.0 g L-1 of PP microplastics and 0.5 mg L-1 of SMX resulted in an enhanced toxic effect. However, no intensified toxic effect on the lettuce was observed when 1.0 g L-1 PP microplastics were added in the presence of 2.5 mg L-1 SMX, indicating that the SMX dominated the toxic effect on lettuce at high concentrations. Additionally, the study found that the water absorption process controlled by the aquaporin and transpiration contributed to the uptake and translocation of SMX in lettuce. When exposed to PP microplastics, no impact was observed on the aquaporin contents of the lettuce while the transpiration rate was significantly decreased by 31.6 % - 44.2 % resulting from microplastics adhered to the root surface. Therefore, in the presence of 2.5 mg L-1 SMX, the SMX uptake in the lettuce root was inhibited by 35.9 % (P < 0.05) when exposed to 1.0 g L-1 PP microplastic. This work deepens our understanding of the behaviour of microplastics and antibiotics in the terrestrial environment.

Fibrous microplastics in the environment: Sources, occurrence, impacts, and mitigation strategies

Fibrous microplastics (FMPs), a unique class of microplastics, are increasingly recognized as a significant environmental threat due to their ubiquitous presence and potential risks to ecological and human health. This review provides a comprehensive overview of FMPs, including their sources, prevalence in various environmental media, and potential impacts. FMPs, which can be found in over 90 % of certain environmental samples, originate from a diverse range of sources, including synthetic textiles, landfill waste, industrial emissions, and atmospheric deposition. These persistent pollutants pose a threat to both terrestrial and marine ecosystems. Their insidious presence can lead to ingestion by organisms, potentially disrupting ecosystems and posing risks to human health. Addressing the challenge of FMPs requires a multi-faceted approach. Reducing the production and use of synthetic fibers, implementing effective waste management practices, and developing new technologies to remove FMPs from wastewater and the broader environment are all crucial components of the solution. However, further research is essential to fully understand the long-term implications of FMPs on ecosystems and human health, laying the foundation for the development of robust and effective mitigation strategies.

Binding between Cu2+/Zn2+ and aged polyethylene and polyethylene terephthalate microplastics in swine wastewaters: Adsorption behavior, and mechanism insights

Microplastics (MPs) have aroused growing environmental concerns due to their biotoxicity and vital roles in accelerating the spread of toxic elements. Illuminating the interactions between MPs and heavy metals (HMs) is crucial for understanding the transport and fate of HM-loaded MPs in specific environmentally relevant scenarios. Herein, the adsorption of copper (Cu2+) and zinc (Zn2+) ions over polyethylene (PE) and polyethylene terephthalate (PET) particulates before and after heat persulfate oxidation (HPO) treatment was comprehensively evaluated in simulated and real swine wastewaters. The effects of intrinsic properties (i.e., degree of weathering, size, type) of MPs and environmental factors (i.e., pH, ionic strength, and co-occurring species) on adsorption were investigated thoroughly. It was observed that HPO treatment expedites the fragmentation of pristine MPs, and renders MPs with a variety of oxygen-rich functional groups, which are likely to act as new active sites for binding both HMs. The adsorption of both HMs is pH- and ionic strength-dependent at a pH of 4-6. Co-occurring species such as humic acid (HA) and tetracycline (TC) appear to enhance the affinity of both aged MPs for Cu2+ and Zn2+ ions via bridging complexation. However, co-occurring nutrient species (e.g., phosphate and ammonia) demonstrate different impacts on the adsorption, improving uptake of Cu2+ by precipitation while lowering affinity for Zn2+ owing to the formation of soluble zinc-ammonia complex. Spectroscopic analysis indicates that the dominant adsorption mechanism mainly involves electrostatic interactions and surface complexation. These findings provided fundamental insights into the interactions between aged MPs and HMs in swine wastewaters and might be extended to other nutrient-rich wastewaters.

Aged Microplastics and Antibiotic Resistance Genes: A Review of Aging Effects on Their Interactions

Background: Microplastic aging affects the dynamics of antibiotic resistance genes (ARGs) on microplastics, yet no review presents the effects of microplastic aging on the associated ARGs. Objectives: This review, therefore, aims to discuss the effects of different types of microplastic aging, as well as the other pollutants on or around microplastics and the chemicals leached from microplastics, on the associated ARGs. Results: It highlights that microplastic photoaging generally results in higher sorption of antibiotics and ARGs due to increased microplastic surface area and functional group changes. Photoaging produces reactive oxygen species, facilitating ARG transfer by increasing bacterial cell membrane permeability. Reactive oxygen species can interact with biofilms, suggesting combined effects of microplastic aging on ARGs. The effects of mechanical aging were deduced from studies showing larger microplastics anchoring more ARGs due to rough surfaces. Smaller microplastics from aging penetrate deeper and smaller places and transport ARGs to these places. High temperatures are likely to reduce biofilm mass and ARGs, but the variation of ARGs on microplastics subjected to thermal aging remains unknown due to limited studies. Biotic aging results in biofilm formation on microplastics, and biofilms, often with unique microbial structures, invariably enrich ARGs. Higher oxidative stress promotes ARG transfer in the biofilms due to higher cell membrane permeability. Other environmental pollutants, particularly heavy metals, antibacterial, chlorination by-products, and other functional genes, could increase microplastic-associated ARGs, as do microplastic additives like phthalates and bisphenols. Conclusions: This review provides insights into the environmental fate of co-existing microplastics and ARGs under the influences of aging. Further studies could examine the effects of mechanical and thermal MP aging on their interactions with ARGs.

The mechanism of UV accelerated aging of polyvinyl chloride in marine environment: The role of free radicals

This study systematically investigated the photo-aging of polyvinyl chloride (PVC) in deionized water, estuary water, and seawater. As the concentration of Cl- increases, the carbonyl index (CI) of PVC during photo aging also increases, indicating that Cl- plays a dominant role in PVC photoaging in the environment, which enhance carbonyl index and •OH radical accumulation. Unlike previous studies, this study discovered that halogen radicals were also generated during PVC aging. Compared to •OH radicals, halogen radicals exhibit stronger selectivity and are more conducive to the photo aging of PVC. Additionally, it was found that PVC shows specific toxicity to Paramecia caudatum at various concentrations both before and after aging, affecting the reproduction process of Paramecia caudatum. This study elucidates the mechanism by which anions in natural water bodies affect the rate of PVC aging, providing a scientific basis for understanding the photodegradation of MPs in the ocean.

Combined effects of microplastics and pharmaceutical and personal care products on algae: A critical review

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are ubiquitous in aquatic environments. Algae play an important role in aquatic environments. Thus, it is important to study the response of algae to combined exposure of MPs and PPCPs. Here, we review the effects of MPs and PPCPs on algae. First, the individual effects of MPs and PPCPs on algae were summarized. Second, the combined effects of MPs and PPCPs on algae were systematically analyzed. (1) Antagonism: ① when the MPs are too large to enter the algal cells, the adsorption of PPCPs onto MPs results in decreased the contact of MPs and PPCPs with algae; ② PPCPs and MPs have opposing actions on the same biological target; ③ MPs increase the activity of metabolic enzymes in algae, thus promoting the PPCP degradation. (2) Synergy: ① when the MPs are small enough to enter algal cells, the adsorption of PPCPs on MPs promotes the entry of PPCPs; ② when MPs are negatively charged, the adsorption of positively charged PPCPs by MPs decreases the electrostatic repulsion, increasing the interaction between algae and MPs; ③ complementary modes of action between MPs and PPCPs show combined effects on the same biological target. Third, the relative importance of the factors that impact the combined effects are evaluated using the random forest model decreased in the following order: PPCP types > algal species > MP size > MP concentration > MP types > exposure time. Finally, future directions for the combined effects of MPs and PPCPs are proposed, which will facilitate a better understanding of the environmental fate and risks of both MPs and PPCPs.

Surface characteristics and adsorption properties of polypropylene microplastics by ultraviolet irradiation and natural aging

The vast application and deep integration of plastic commodity with our human lives raise a great concern about the ubiquitous microplastics (MPs) in nature, yet the environmental behavior of MPs remain unclear. As a main type and candidate of MPs, pristine polypropylene MPs (PP-MP-Pris), as well as the influence of ultraviolet (UV) irradiation on the degree of aging and surface characteristics, were characterized quantitatively by Fourier infrared spectroscopy, scanning electron microscopy, contact angle meter, automatic specific surface area and pore analyzer and laser particle analyzer, with natural aged PP-MPs (PP-MP-Age) as comparison. The carbonyl index (CI) of UV aged PP-MPs (PP-MP-U) was increased with extension of exposure time, while biofilm with abundant functional groups and the maximum CI value were the characteristics of PP-MP-Age. Moreover, the adsorption capacity of PP-MP-U for crystal violet (CV) was increased and reached the maximum after 30 days, while that of PP-MP-Age was weakened, probably due to the enhanced hydrophilicity and the shedding of calcium carbonate (CaCO3) during the natural aging process, which was demonstrated by hydrochloric acid treatment, indicating the vital involvement of CaCO3. Moreover, the better fitting to PSO kinetics and Freundlich isotherm models indicated that the multilayered and non-homogeneous surface adsorption was acted as the rate-controlling step. Furthermore, the positive values of ΔGθ, ΔHθ and ΔSθ indicated that the adsorption was a non-spontaneous, endothermic process with increased degree of the freedom on the interface of PP-MPs and CV solution. The presence of divalent salts inhibited CV adsorption, demonstrating that electrostatic attraction played a major role in CV capture. The hydrophobic interaction, micropore filling, hydrogen bonding, and π - π conjugation were possible involved. This study is of great significance for better understanding the complex pollution of MPs and its potential environmental risks in the future.

Alleviating effects of microplastics together with tetracycline hydrochloride on the physiological stress of Closterium sp

Microplastics have significant influence on both freshwater cyanobacteria and marine microalgae, especially under co-exposure with other pollutants such as heavy metals, antibiotics, and pharmaceuticals. In the present study, combined effects of microplastics (polyethylene terephthalate (PET) or polybutylene terephthalate (PBT)) and tetracycline hydrochloride (TCH) on the microalgae Closterium sp. were studied to evaluate their acute toxicity, and the cell density, total chlorophyll concentration, photosynthetic activity, antioxidant system, and subcellular structure of Closterium sp. under different treatments were used to explain the physiological stress mechanism of the combined effects. The results indicate that both the single and combined treatments have inhibition effects on the cell growth and photosynthetic activity, with inhibition efficiencies (in terms of cell density) of 5.0%, 9.2%, 66.7%, 55.1%, and 59.8% for PET (100 mg L-1), PBT (100 mg L-1), TCH (10 mg L-1), PET/TCH (PET 100 mg L-1 and TCH 10 mg L-1), and PBT/TCH (PBT 100 mg L-1 and TCH 10 mg L-1), respectively, and relative electron-transport rates (rETRs) of 7.3%, 12.7%, 66.8%, 54.0%, and 59.9%, respectively, for each treatment compared with the control on the 7th day. Moreover, both PET and PBT have positive effects in alleviating TCH toxicity toward Closterium sp., and at the same time, the malondialdehyde level (MDA), superoxide dismutase (SOD) activity, and catalase (CAT) activity induced by the combined treatments were much higher than those from the single microplastic treatments but lower than those from TCH treatment after 7 days. It was demonstrated that TCH causes a much more serious oxidative stress than PET/TCH and PBT/TCH, and the lower oxidative stress of the PET/TCH and PBT/TCH groups could be attributed to the adsorption of TCH to PET or PBT. This work improves the understanding of the combined toxicity effects of microplastics and TCH on Closterium sp.