Effect of microplastic size on the adsorption behavior and mechanism of triclosan on polyvinyl chloride

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.

The potential of microplastics acting as vector for triclosan in aquatic environments

There is increased evidence of the co-occurrence of microplastics (MPs) with other co-pollutants in surface water globally, leading to ecological and environmental concerns. The risks and toxicity of co-occurring pollutants largely depend on the mechanisms controlling the activation of their various sources, their fate and transport in different environmental media. Due to their size-specific surface area, MPs in the environment can have a strong affinity for interactions with hydrophobic compounds and have a high sorption capacity for various emerging contaminants (ECs). ECs like the antibacterial and antifungal agent such as Triclosan (TCS) are persistent in the environment. Moreover, TCS in aquatic environments has a low solubility, and high octanol-water partitioning co-efficient which raises the possibility of TCS to interact with other environmental pollutants such as MPs. The interactions of TCS with MPs in the environment are controlled by a range of mechanism such as hydrogen bonding, hydrophobic interactions, π-π interactions as well as electrostatic interactions. The interacting behaviour of these driving forces needs to be fully understood to determine how the co-occurrence of TCS and MPs may lead to adverse effects on the biological functioning of aquatic ecosystems. Hence, here we conduct a systematic review of the current state-of-the-art and synthesize the available knowledge of how MPs can act as vectors for TCS in aquatic environments. This review reveals MP and TCS interactions in aquatic ecosystems, their individual and collective fate, and toxicological impacts on aquatic organisms, evidencing that MPs can act as potential vectors for transporting TCS across different trophic levels. This review also reveals critical limitations in the research of the combined toxicity and interactions of co-occurring MPs and TCS. Based on the rigorous review of the current knowledge base, we propose that multifactorious investigations along with long-terms monitoring are crucial to fully understand the impacts of co-occurring MPs and TCS in aquatic systems to underline future mitigation policies and management plans.

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.

The Impact of Microplastics on Adsorption of Chlorophenols by River-Suspended Sediments

Although microplastics (MPs) are widely recognized as carriers of environmental pollutants, their impact on the adsorption behavior of chlorophenols (CPs) by river-suspended sediments (SS) remains poorly understood. This study systematically investigated the effects of three common MPs (PVC, PS, and PE) on the adsorption of 4-chlorophenol (MCP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) by SS from the Yellow River. Adsorption isotherms revealed that PVC significantly promoted CP adsorption, fitting well with the Langmuir model (R² > 0.95), whereas PS and PE showed better agreement with the Freundlich model (R² > 0.96). The enhancement effect varied with MP type and CP species, with PVC demonstrating the most pronounced promotion (65% increase for 2,4,6-TCP). Conversely, PS and PE hindered 2,4-DCP adsorption due to its higher partition coefficient in SS (36.83 ± 6.3 L/kg) compared to MPs (1.85 ± 0.01 L/kg for PS and 2.03 ± 0.05 L/kg for PE). Environmental factor analysis revealed that ionic strength exerted dual effects by initially enhancing CP adsorption through reduced solubility and later inhibiting it via electrostatic repulsion. Humic acid (HA) promoted TCP adsorption but inhibited DCP adsorption through aggregation and dispersal mechanisms on SS surfaces. Acidic conditions (pH 2-6) significantly enhanced CP adsorption by maintaining their molecular states, while alkaline conditions reduced adsorption due to electrostatic repulsion. Mechanistically, MPs altered SS surface properties and formed aggregates that either facilitated or competed for CP adsorption sites. This study provides a theoretical basis for ecological risk assessment of combined microplastic-pollutant contamination in sediment-laden rivers.

Charged polystyrene microplastics inhibit uptake and transformation of 14C-triclosan in hydroponics-cabbage system

INTRODUCTION

Since the outbreak of COVID-19, microplastics (MPs) and triclosan in pharmaceuticals and personal care products (PPCPs) are markedly rising. MPs and triclosan are co-present in the environment, but their interactions and subsequent implications on the fate of triclosan in plants are not well understood.

OBJECTIVE

This study aimed to investigate effects of charged polystyrene microplastics (PS-MPs) on the fate of triclosan in cabbage plants under a hydroponic system.

METHODS

14C-labeling method and liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (LC-QTOF-MS) analysis were applied to clarify the bioaccumulation, distribution, and metabolism of triclosan in hydroponics-cabbage system. The distribution of differentially charged PS-MPs in cabbage was investigated by confocal laser scanning microscopy and scanning electron microscopy.

RESULTS

The results showed that MPs had a significant impact on bioaccumulation and metabolism of triclosan in hydroponics-cabbage system. PS-COO-, PS, and PS-NH3+ MPs decreased the bioaccumulation of triclosan in cabbage by 69.1 %, 81.5 %, and 87.7 %, respectively, in comparison with the non-MP treatment (control). PS-MPs also reduced the translocation of triclosan from the roots to the shoots in cabbage, with a reduction rate of 15.6 %, 28.3 %, and 65.8 % for PS-COO-, PS, and PS-NH3+, respectively. In addition, PS-NH3+ profoundly inhibited the triclosan metabolism pathways such as sulfonation, nitration, and nitrosation in the hydroponics-cabbage system. The above findings might be linked to strong adsorption between PS-NH3+ and triclosan, and PS-NH3+ may also potentially inhibit the growth of cabbage. Specially, the amount of triclosan adsorbed on PS-NH3+ was significantly greater than that on PS and PS-COO-. The cabbage biomass was reduced by 76.9 % in PS-NH3+ groups, in comparison with the control.

CONCLUSION

The uptake and transformation of triclosan in hydroponics-cabbage system were significantly inhibited by charged PS-MPs, especially PS-NH3+. This provides new insights into the fate of triclosan and other PPCPs coexisted with microplastics for potential risk assessments.

Sorption and dissipation of current-use pesticides and personal-care products on high-density polyethylene microplastics in seawater

Sorption kinetics and the desorption of three current-use pesticides (CUPs: methyl-chlorpyrifos - m-CPF -, pendimethalin and propyzamide) and three personal-care products (PCPs: triclosan - TCS-, tonalide and galaxolide) on high-density polyethylene (HDPE) in seawater were characterised in this study. Sorption kinetic equilibrium and mass balance were determined for all contaminants, evidencing simultaneous dissipation processes (degradation, volatilization, etc.) after 72 h, particularly for propyzamide, pendimethalin, galaxolide and tonalide. However, they were lower than 24 % for TCS and m-CPF, getting the steady-state for all considered analytes in 24 h. The concentration of contaminants sorbed on HDPE increased with the hydrophobicity from 13.9 ng g-1 to 35.1 ng g-1 for m-CPF and TCS, respectively. No clear effect of temperature was observed for m-CPF sorption, and apparently the sorption of TCS was higher at 15 °C than at 25 °C, but it can be affected by the higher dissipation at 25 °C for this compound. This study confirmed the desorption of TCS and m-CPF from HDPE, being higher than 30 % in all cases during the first 24 h, especially for the highest tested concentrations (200 ng L-1). Sorption of TCS and m-CPF were favoured (4-7 times) on HDPE with the highest specific surface (estimated in an increase of 49-fold times).

The role of marine microalgae in the transmission of HOCs from contaminated microplastics in the aqueous environment

The prevalence of microplastics in marine environments is recognized for its ecotoxicological risks as vectors for hydrophobic organic contaminants (HOCs). This study explored the role of microalgae as vectors in the transfer of Phenanthrene (Phe) from contaminated microplastics to marine filter feeders. Employing a spatial exposure system, the sorption of Phe onto polyethylene (PE) particles, its desorption mediated by microalgae into microalgal suspensions, and subsequent accumulation in the tissues of filter feeders were investigated. In the spatial exposure system for clams, after 28 days of exposure, Phe concentrations in clams' tissues were 67.71 ng/g and 84.21 ng/g for the medium with and without microalgae, respectively; however, no statistically significant difference was observed between them (p > 0.05). In the spatial exposure system for mussels, the highest Phe concentrations in mussels' tissues were 277.71 ± 25.98 μg/g in the digestive glands after 3 days of exposure and 185.32 ± 35.76 μg/g in the mantle after 6 days of exposure, both in the Tetraselmis helgolandica suspension. Significant differences were observed between the control group and the T. helgolandica suspension group from 3 to 10 days of exposure (p < 0.05). Although microalgae were confirmed to enhance the desorption of Phe from PE particles, their role in significantly increasing the bioaccumulation of Phe in filter feeders was less than anticipated, showing no significant long-term differences between experimental groups with and without microalgae. The potential biodegradation of Phe by marine organisms was also observed, which may have contributed to the overall transfer and bioaccumulation processes, introducing an additional layer of complexity to the interpretation of the results. These findings suggest that microalgae can act as intermediate carriers facilitating the transfer of Phe, albeit with the impact of various influencing factors not aligning with initial hypotheses. The study highlights the need for further investigation into how different microalgal species and environmental conditions affect the fate of HOCs absorbed by microplastics, contributing to an enriched understanding of microplastic impacts in marine ecosystems. This establishes that microalgae mediate the transfer of Phe from microplastics into benthic filter feeders, affirming their role as significant vectors in contaminant dynamics.

Microplastic aging and adsorption in the atmosphere, and their associated impacts on various spheres of the earth: A review

Microplastic (MPs, size <5 mm) is an emerging category of contaminants with detrimental effects on human health, climate, and ecology. The atmospheric pathway is a crucial transport route for the migration of MPs from source to receptor locations. This long-range transport leads to the ubiquitous presence of MPs across all environmental matrices and constrains the source-transport pathway-sink interaction. During atmospheric transport, MPs experience aging and adsorption as a result of interactions with winds, solar radiation, moisture, pH, and atmospheric pollutants, which alters their hydrophilicity, structure, surface area, size, color, and the capacity for adsorption, often resulting in elevated toxicity and associated risks. However, the multifaceted dynamics of atmospheric aging of MPs and consequent impacts are poorly understood. This review presents a critical assessment of three major factors that determine the nature and degree of MP aging and adsorption in the atmosphere, namely: intrinsic MP properties such as the degree of unsaturation, crystallinity, presence of functional groups, charge, specific surface area, and structural defects; environmental factors such as temperature, pH, moisture, and the presence of chemical species; and pollutant characteristics such as charge and hydrophilicity/hydrophobicity that influence adsorption, with an emphasis on potential mechanisms. Additionally, the review presents a comparative assessment of the critical factors and mechanisms responsible for aging and adsorption in atmosphere with those in other environmental media. Further, the potential impacts of atmospherically aged MPs on climate, the biosphere, cryosphere, pedosphere, and hydrosphere are summarized. The review finally identifies key knowledge gaps and outlines perspectives for future research.

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.

Interfacial sorption of 17β-E2 on nano-microplastics: Effects of particle size, functional groups and hydrochemical conditions

Nano-microplastics and 17β-E2 have been frequently detected as emerging high-concern pollutants in aquatic systems, and their interaction at the solid/liquid interface has become a research focus in environmental studies. The interfacial sorption kinetics and equilibrium characteristics of 17β-estradiol (17β-E2) on nano-polystyrene (Nano-PS) with different particle sizes and organic functional group modifications were systematically investigated in aqueous environments in this study. The interfacial interaction mechanism between Nano-PS particles and 17β-E2 was elucidated by utilizing SEM, FTIR, XPS and BET techniques. The experimental results demonstrated that the interfacial sorption kinetics of 17β-E2 on different Nano-PS were rapid, in accordance with the pseudo-first-order models. Both Langmuir and Freundlich models provided a nice description of 17β-E2 sorption equilibrium on Nano-PS, indicating that physical effects predominantly governed the interfacial interactions. Modification of Nano-PS by -OH and -NH2 resulted in increase in polarity, decrease in hydrophobicity and reduction in the sorption capacity for 17β-E2, suggesting that hydrophobic partitioning primarily controlled the interfacial interaction between Nano-PS and 17β-E2. Furthermore, the superior sorption capacity of PS100-OH relative to PS100-NH2 can primarily be attributed to the enhanced hydrogen bonding capability provided by the -OH group. The sorption capacity of 17β-E2 by the same Nano-PS was inversely proportional to the particle size, indicating that a smaller particle size possessed larger specific surface area, thereby providing more active sites and facilitating more pore filling. Low temperature promoted the sorption process and increased the sorption capacity. This study established a scientific foundation for better assessment of the environmental behavior arising from co-pollution of nano-microplastics and endocrine disruptors (EDCs).

Sorption kinetics of metallic and organic contaminants on micro- and nanoplastics: remarkable dependence of the intraparticulate contaminant diffusion coefficient on the particle size and potential role of polymer crystallinity

We developed a mechanistic diffusion model to describe the sorption kinetics of metallic and organic contaminants on nano- and micro-plastics. The framework implements bulk depletion processes, transient fluxes, and fully adaptable particle/water boundary conditions, i.e. not only the typically assumed simple linear Henry regime, which is not applicable to many contaminant-particle situations. Thus, our model represents a flexible and comprehensive theory for the analysis of contaminant sorption kinetics, which goes well beyond the traditional empirical pseudo first or second order kinetic equations. We applied the model to the analysis of a large body of literature data on the equilibrium and kinetic features of sorption of a wide range of contaminants by diverse types and sizes of plastic particles. Results establish the paramount importance of sorption boundary conditions (Henry, Langmuir, or Langmuir-Freundlich) and reveal interesting and often overlooked sorption features that depend on the plastic particle size and the extent to which the target compound is depleted in the bulk medium. The greater degree of polymer crystallinity reported for smaller particles may underlie our findings that the intraparticulate contaminant diffusion coefficient decreases with a decreasing particle size. We establish a universal law to predict the sorption kinetics and diffusion of any compound within any plastic phase, which has far reaching importance across many domains relevant to the environment and human health.

Understanding the interaction between selected microplastics and the toxic dye "Congo red" in water

This study thoroughly investigated the adsorption of Congo Red (CR) dye onto various microplastics (MPs), including high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP) and polyethylene terephthalate (PET). Initial adsorption capacities (qe) revealed that HDPE had the highest value (21.90 mg/g), followed by PVC (4.2 mg/g), LDPE (3.7 mg/g), PP (3.1 mg/g) and PET (2.8 mg/g). Based on these findings, HDPE and PVC were selected for detailed analysis. Adsorption experiments were conducted under controlled conditions: CR concentration of 100 mg/L, adsorbent dosage of 2 g/L, pH of 5, and temperature of 303 K. Isotherm studies indicated that HDPE followed the Freundlich model (R2 - 0.99), while PVC was best described by the Redlich-Peterson model (R2 - 0.97). Kinetic analysis showed that HDPE adhered to the Bangham model (reliable ((R2 = 0.9267, 0.950, 0.988, and 0.988) R2 values obtained for all the concentrations), highlighting pore-filling mechanisms. The conclusion, supported by FTIR analysis, indicates no significant changes in HDPE's functional groups after the adsorption. In contrast, PVC followed a pseudo-second order kinetic model (reliable R2 values (0.999, 0.765, 0.956, 0.972) obtained for all the concentrations), suggesting chemisorption, confirmed by FTIR changes in the C-Cl bonds. The optimal pH for adsorption was 5 for HDPE and 4 for PVC. Both processes were exothermic with intraparticle and film diffusion identified as rate-limiting steps. Maximum adsorption capacities (qmax) were 110.1 mg/g for HDPE and 8.1 mg/g for PVC. Desorption experiments were conducted only for HDPE due to PVC's lower adsorption. The highest desorption for HDPE occurred at pH 4 (5.7 mg/L) with an adsorbent dosage of 2 g/L. This study underscores the dual environmental threat posed by MPs, which not only adsorb organic pollutants like CR but also release them under certain conditions. While this research advances our understanding of MPs as pollutant carriers, future work should focus on their desorption behavior in complex, real-world environments. Further studies on other organic pollutants and microplastic types in real wastewater systems are also recommended.

Environmental release behavior, cell toxicity and intracellular distribution of novel biodegradable plastic materials

In response to the increasingly severe issue of plastic waste, biodegradable plastics have garnered extensive attention as a potential alternative to traditional plastics. Among these materials, biodegradable plastics hold a dominant position. The objective of this study was to assess the environmental risks of five commercially available biodegradable plastics: polyglycolic acid (PGA), polylactic acid (PLA), poly(butylene succinate) (PBS), poly(butylene carbonate) (PBC), and poly(butylene adipate-co-terephthalate) (PBAT). The evaluation included their physical properties, microplastic release behavior, and cytotoxicity. In addition, the effect of age process on the environmental behavior of biodegradable plastic materials was further investigated. The results revealed that PGA and PBS exhibited lower risks in terms of microplastic release, whereas PLA demonstrated higher environmental mobility. Further cytotoxicity experiments indicated that PLA and PBS exerted significant toxic effects on human cell lines, including human normal liver cells (LO2), human monocytic leukemia cells (THP-1), human umbilical vein endothelial cells (HUVECs), and human colon carcinoma cells (Caco-2). Additionally, this study utilized Nile Red labeling to observe the co-culture system of PGA with THP-1 cells, uncovering that THP-1 cells gradually engulfed and internalized PGA microplastics over time. This finding provides new insights into the potential mechanism by which microplastics promote cell proliferation. Moreover, we also found that the aging process partially reduced the cytotoxicity of PGA, but had little effect on environmental mobility. Considering the comprehensive research findings, PGA is considered an ideal material for large-scale applications due to its low cytotoxicity and environmental risks. In contrast, the environmental safety of other types of plastics requires more comprehensive risk assessment to determine their suitability. This study provides significant scientific evidence for the environmental impact assessment of biodegradable plastics and plays a crucial role in promoting the development of sustainable plastic alternatives.

Degradation of polyvinyl chloride (PVC) microplastics employing the actinobacterial strain Streptomyces gobitricini

The disposal of plastic materials has resulted in the huge increase of microplastics in the environment. One of the most hazardous plastic waste is polyvinyl chloride (PVC) due to its durability. A tool to remediate PVC microplastic polluted environment might be offered by microorganisms such as Actinobacteria, which has been proven to degrade PVC. Streptomyces gobitricini was isolated from soil polluted by heavy metals and plastic debris and used in a PVC microplastics degradation experiment. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM) were used to study the characteristics of microplastic particles. For the incubation, the optimal pH 7.5 was determined in a preliminary experiment where also pH 5.5 and pH 9.5 were included. Three PVC concentrations (200, 400, and 800 mg/L) were incubated in Luria-Bertani broth with S. gobitricini for 90 days. After the incubation, PVC-MP particles were recovered by filtering. The percentual weight loss of microplastics was highest (66%) in 200 mg/L treatment. Relatively high reductions were observed for the higher microplastic concentrations as well (400 mg/L; 65% and 800 mg/L; 60%). The bacterial growth decreased in order 200 mg/L (3.1 ± 0.1 CFU × 105/mL), 400 mg/L (3.0 ± 0.0 CFU × 105/mL) and 800 mg/L treatment (2.7 ± 0.0 CFU × 105/mL). High hydrophobicity was observed in all treatments at the end of the incubation indicating the formation of bacterial biofilm on the surfaces of plastic particles. The highest hydrophobicity (84%) associated with the bacterial strain was observed in 200 mg/L microplastics treatment. The results show that the bacterium S. gobitricini suits for further studies to reduce PVC microplastic waste in the environment.

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.

Co-Existing Nanoplastics Further Exacerbates the Effects of Triclosan on the Physiological Functions of Human Serum Albumin

The potential health risks posed by the coexistence of nanoplastics (NPs) and triclosan (TCS) have garnered significant attention. However, the effects and underlying mechanisms of NPs and TCS on key functional proteins at the molecular level remain poorly understood. This study reports the effect of polystyrene nanoplastics (PSNPs) on the binding of TCS to human serum albumin (HSA) using multispectral methods and molecular simulation systems. The experimental results show that TCS significantly inhibits HSA esterase activity, with exacerbating inhibition in the presence of PSNPs, which is attributed to the alteration of HSA conformation and microenvironment of the amino acid residues induced by PSNPs. Molecular docking and site marker competitive studies indicate that TCS predominantly binds to site I of subdomain Sudlow II and the presence of PSNPs does not affect the binding sites. Spectra analyses indicate that the quenching mechanism between TCS and HSA belongs to the static quenching type and the presence of PSNPs does not change the fluorescence quenching type. The HSA fluorescence quenching and the conformational alterations induced by TCS are further enhanced in the presence of PSNPs, indicating that PSNPs enhance the binding of TCS to HSA by making TCS more accessible to the binding sites. This study provides valuable information about the toxicity of PSNPs and TCS in case of co-exposure.

Adsorption and Desorption Behavior of Cr(VI) on Two Typical UV-Aged Microplastics in Aqueous Solution

Microplastics (MPs) are novel pollutants that can adsorb heavy metals in water environments and migrate together as carriers and are prone to aging due to the light in water. However, few reports have been published on the synergistic behavior and effects of these different types of aged MPs on the adsorption and desorption of Cr(VI). Here, two MP types─polyamide (PA) and polylactic acid (PLA)─were aged by UV irradiation, and the adsorption and desorption behaviors of MPs on Cr(VI) were studied. The results indicated that UV light can rapidly age MPs. After the MPs were exposed to UV light, their specific surface area, negative charge, and oxygenic groups increased, resulting in enhanced hydrophilicity. The aged MPs depicted a markedly enhanced adsorption capacity for Cr(VI) compared with the results of aged-PA > pristine-PA > aged-PLA > pristine-PLA. The process followed the Langmuir and pseudo-second-order models, confirming that chemical and monolayer adsorption are the primary processes involved in the adsorption of Cr(VI) by aged MPs. Cr(VI) was more easily desorbed in the simulated gastric fluid environment. The desorption rate of aged MPs was lower than that of pristine MPs because of their stronger binding forces to Cr(VI). The binding of Cr(VI) to MPs mainly depends on synergistic mechanisms such as electrostatic attraction, reduction reactions, and chelation of oxygenic groups. This study clarifies the reciprocity mechanism between aging MPs and Cr(VI) and provides further insights and guidance for controlling the joint pollution between MPs and heavy metal pollutants in the future.

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.

Environmental microplastic and phthalate esters co-contamination, interrelationships, co-toxicity and mechanisms. A review

Plastics have been pervasive in society for decades, causing extensive environmental contamination. The co-occurrence of microplastics (MPs) and phthalate esters (PAEs) in the environment has significant implications for the global population. This review focuses on the simultaneous presence of MPs and PAEs, exploring co-pollution, leaching, adsorption, correlation, and co-toxicity. Both MPs and PAEs are found in various environmental compartments, including water, sediments, aquatic organisms, pig feed, masks, gloves, and liquid waste from garbage infiltration. Factors such as time, temperature, UV light exposure, and the type of MPs can influence the leaching and adsorption of PAEs onto MPs. The correlation between MPs and PAEs allows for the use of PAEs as indicators for the presence of MPs. However, current constraints, like limited data availability and regional coverage, impede the feasibility of comprehensive tracking. Additionally, the combined effects of MPs and PAEs demonstrate synergistic toxicity, leading to adverse health effects such as reproductive toxicity, neurotoxicity, hepatotoxicity, nephrotoxicity, and other toxicities, primarily mediated by oxidative stress processes. Consequently, the findings provide valuable insights for future researchers and regulatory bodies, enabling the development of more effective strategies to address the simultaneous presence of microplastics and PAEs and mitigate their harmful impacts on human health.

Assessing the interaction between 4-methylbenzylidene camphor and microplastic fibers in aquatic environments: Adsorption kinetics and mechanisms

Wastewater treatment plants play a crucial role in managing environmental pollutants, but they often release persistent contaminants like synthetic microplastic fibers (MPFs) into ecosystems. These microplastics, mainly from the textile industry and domestic washing of synthetic fabrics, are a major type of microplastic found in aquatic environments. Some harmful chemicals have an affinity for these microplastics, making them vectors for contaminants. This study investigates the adsorption of 4-methylbenzylidene camphor (4-MBC), an organic UV filter, onto microplastic fibers from two different sources. Batch experiments conducted at room temperature (25 °C) under laboratory conditions assessed the adsorption kinetics and mechanisms. Morphological and visual characterization of the microplastic fibers was done using optical microscopy and scanning electron microscopy (SEM), revealing diverse shapes, types, and colors. Physico-chemical properties were confirmed through thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). The data matched well with the PSO kinetic model and Langmuir isotherm, indicating monolayer chemisorption with equilibrium achieved within 24 h. The adsorption mechanisms involved electrostatic attraction, hydrogen bonding, and π-π interactions. Both types of microplastic fibers exhibited a tendency to adsorb 4-MBC, indicating the significance of this research in understanding the interactions between this compound and various fiber types emphasizing the need for further research under the different environmental conditions.

Ameliorating arsenic and PVC microplastic stress in barley (Hordeum vulgare L.) using copper oxide nanoparticles: an environmental bioremediation approach

The present study investigates the impact of varying concentrations of PVC microplastics (PVC-MPs) - specifically 0 (no PVC-MPs), 2, and 4 mg L- 1 -alongside different arsenic (As) levels of 0 (no As), 150, and 300 mg kg- 1 in the soil, with the concurrent application of copper oxide-nanoparticles (CuO-NPs) at 0 (no CuO -NPs), 25 and 50 µg mL- 1 to barley (Hordeum vulgare L.) plants. This research primarily aims to assess plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators, as well as the response of various antioxidants (both enzymatic and non-enzymatic) and their relevant genes expression, proline metabolism, the AsA-GSH cycle, and cellular fractionation within the plants. The findings showed that increased levels of PVC-MPs and As stress in the soil significantly reduced plant growth and biomass, photosynthetic pigments, and gas exchange characteristics. Additionally, PVC-MPs and As stress increased oxidative stress in the roots and shoots, as evidenced by elevated levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL), which in turn stimulated the production of various enzymatic and non-enzymatic antioxidants, gene expression, and sugar content. Furthermore, a notable increase in proline metabolism, the AsA-GSH cycle, and cellular pigmentation was observed. Conversely, the application of CuO-NPs resulted in a substantial improvement in plant growth and biomass, gas exchange characteristics, and the activity of enzymatic and non-enzymatic antioxidants, along with a reduction in oxidative stress. Additionally, CuO-NPs enhanced cellular fractionation while decreasing proline metabolism and the AsA-GSH cycle in H. vulgare plants. These outcomes provide new insights into sustainable agricultural practices and offer significant potential in addressing the critical challenges of heavy metal contamination in agricultural soils.

The influence of digestive tract protein on cytotoxicity of polyvinyl chloride microplastics

Microplastics in food and drinking water can enter the human body through oral exposure, posing potential health risks to the human health. Most studies on the toxic effects of microplastics have focused on aquatic organisms, but the effects of the human digestive environment on the physicochemical properties of microplastics and their potential toxicity during gastrointestinal digestion are often limited. In this study, we first studied the influence of interactions between digestive tract protein (α-amylase, pepsin, and trypsin) and microplastics on the activity and conformation of digestive enzymes, and the physicochemical properties of polyvinyl chloride microplastics (PVC-MPs). Subsequently, a simulated digestion assay was performed to determine the biotransformation of PVC-MPs in the digestive tract and the intestinal toxicity of PVC-MPs. The in vitro experiments showed that the protein structure and activity of digestive enzymes were changed after adsorption by microplastics. After digestion, the static contact angle of PVC-MPs was decreased, indicating that the hydrophilicity of the PVC-MPs increased, which will increase its mobility in organisms. Cell experiment showed that the altered physicochemical property of PVC-MPs after digestion process also affect its cytotoxicity, including cellular uptake, cell viability, cell membrane integrity, reactive oxygen species levels, and mitochondrial membrane potential. Transcriptome analyses further confirmed the enhanced biotoxic effect of PVC-MPs after digestion treatment. Therefore, the ecological risk of microplastics may be underestimated owing to the interactions of microplastics and digestive tract protein during biological ingestion.

Removal of microplastics from aqueous media using activated jute stick charcoal

Microplastics (MPs), which are repositories of various pollutants, have significant effects on the people and the environment. Therefore, there is an urgent need for efficient and eco-friendly techniques to eliminate microplastics from water-based environments. This study introduces a new method for producing jute stick-activated charcoal (JSAC) by placing jute sticks on high-temperature pyrolysis without oxygen, followed by chemical activation with HCl. This process greatly enhances the adsorption capacity of JSAC for polyvinylchloride-based microplastics (PVC-MPs). JSAC was characterized using UV-Vis, FT-IR, XRD, and SEM studies both before and after adsorption. The study investigated the influence of pH, adsorbent quantity, and contact time on the optimization of the JSAC process. The PVC-MPs exhibited a maximum adsorption capacity of 94.12 % for the target MPs (5 g L-1) within 120 min when 10 g L-1 of JSAC was added at pH 7. This work also examined adsorption rate and various isotherm models. Adsorption kinetics analysis reveals electrostatic, hydrogen bond, π-π, and hydrophobic interactions are the combined forces responsible for MPs adsorption onto JSAC. However, the decrease in hydrophobicity in acidic or basic media led to a decrease in adsorption. The isotherm analysis was conducted using the Langmuir isotherm model, and predicted the maximum adsorption capacity of PVC-MPs to be 4.4668 mg/g. Furthermore, by employing density functional theory, the interaction energy after PVC-MP adsorption was calculated to be -269 kcal/mol, demonstrating robust adsorption and agreement with the experimental findings. Due to its large surface area and porous structure containing many functional groups, JSAC can potentially be used to treat MP contamination in water.

Adsorption behavior and mechanism of different types of (aged) microplastics for napropamide in soils

The role of microplastics (MPs) as pollutant carriers and their influence on the fate of organic pollutants has received considerable attention. However, the impacts of MPs on the adsorption of amide herbicides in soil, have not been investigated. In this study, non-biodegradable (polyethylene, PEM) and biodegradable (polybutylene adipate terephthalate, PBATM) MPs were aged by exposure to one month of ultraviolet irradiation. The impacts of MPs on the adsorption of napropamide (Nap) in two agricultural soils (black soil [BS] and fluvo-aquic soil [CS]) were investigated through batch experiments. The findings suggested that the adsorption of Nap onto PEM was mainly governed by physical processes, while, chemical mechanisms, should not be overlooked on PBATM. With the addition of 0.2% MPs, the maximum adsorption capacity (Qm) and adsorption distribution coefficient (KF) of soil containing PEM (soil-PEM) were higher than that of soil-PBATM, however, the Qm and KF values of soil-PBATM for Nap were higher when the addition of MPs was 2%. After UV aging, the increased specific surface area of MPs led to an increased adhesion of soil particles. These were attributed to the different surface properties and concentrations of different (aged) MPs, resulting in differences in the inhibition effect by soil particles. The adhesion of soil particles was confirmed by X-ray photoelectron spectroscopy. Additionally, regardless of the addition of MPs, the Qm values of BS for Nap were higher than those for CS. In summary, MPs can alter the adsorption of Nap in soil, influencing both its mobility within the soil ecosystem and the environmental risk.

Colonization characteristics and surface effects of microplastic biofilms: Implications for environmental behavior of typical pollutants

This paper summarizes the colonization dynamics of biofilms on microplastics (MPs) surfaces in aquatic environments, encompassing bacterial characteristics, environmental factors affecting biofilm formation, and matrix types and characteristics. The interaction between biofilm and MPs was also discussed. Through summarizing recent literatures, it was found that MPs surfaces offer numerous benefits to microorganisms, including nutrient enrichment and enhanced resistance to environmental stress. Biofilm colonization changes the surface physical and chemical properties as well as the transport behavior of MPs. At the same time, biofilms also play an important role in the fragmentation and degradation of MPs. In addition, we also investigated the coexistence level, adsorption mechanism, enrichment, and transformation of MPs by environmental pollutants mediated by biofilms. Moreover, an interesting aspect about the colonization of biofilms was discussed. Biofilm colonization not only had a great effect on the accumulation of heavy metals by MPs, but also affects the interaction between particles and environmental pollutants, thereby changing their toxic effects and increasing the difficulty of MPs treatment. Consequently, further attention and research are warranted to delve into the internal mechanisms, environmental risks, and the control of the coexistence of MPs and biofilms.

The competition of heavy metals between hyporheic sediments and microplastics of driving factors in the Beiluo River Basin

Both sediments and microplastics (MPs) are medias of heavy metals (HMs) in river ecosystems. This study investigated HMs (Mn, Cr, V, As, Cu, Co, Cd, Pb, and Ni) concentration and driving factors for competitive enrichment between hyporheic sediments versus MPs. The medias basic characteristics indicated that the sediments were mostly sand and rich in Fe2O3; three polymer types were identified, with blue, fragment, less than 500 µm being the main types of MPs. The results have shown that the average content of extracted HMs in MPs was much higher than that of the same metals accumulated in sediments. HMs in sediments and MPs reached heavily polluted at some points, among which As and Cd were ecological risks. Electrostatic adsorption and surface complexation, and biofilm-mediated and organic matter complexation were the interaction mechanism of HMs with sediments and MPs. Further, the driving factors affecting the distribution of HMs in the two carriers were analyzed by multivariate statistical analysis. The results demonstrated that carrier characteristics, hydrochemical factors, and the inherent metal load of MPs were the main causes of the high HMs content. These findings improved our understanding of HMs fate and environmental risks across multiple medias.

Impact on sulfadiazine bio-accessibility in soils through organic diffusive gradients in thin films (o-DGT): Differentiation based on microplastic polymers, aging, and soil properties

Due to the similar sources of swage irrigation, organic fertilizer, and sludge application, microplastics (MPs) and antibiotics coexist inevitably in the agriculture soils. However, the impacts of MPs with different polymer types and aging status on the bio-accessibility of co-existing antibiotics in soils remained unclear. Therefore, we using the diffusive gradients films for organic compounds devices (o-DGT) to evaluated the distribution of sulfadiazine (SDZ) in both paddy soil and saline soil amended with 0.5 % (w/w) MPs. Four polymer types (polyethylene: PE, polypropylene: PP, polyamide: PA, and polyethylene terephthalate: PET) and two aging statuses (aged PE and aged PP) of MPs were used in this study. Results showed that soil properties significantly influence the partition of SDZ in soil and soil solution, and SDZ gained a lower degradation rate but higher mobility in saline soil. MPs pose different impacts on partition of SDZ between paddy soil and saline soil. Notably, PP reduced the labile solid phase-solution phase partition coefficient (Kdl) by 17.7 % in paddy soil, while PE, PP, and aPE increased the Kdl value by 2.00, 1.62, and 2.81 times in saline soil. Besides, in saline soil, all the MPs reduced the SDZ concentration in the soil solution, while significantly increased the SDZ in o-DGT phase. Conversely, MPs did not impact the SDZ's o-DGT concentration in paddy soil. Additionally, MPs increased the R value of SDZ in two soils, especially in saline soil. It suggested that MPs could potentially enhance the resupply of SDZ from soil to plants, particularly under saline conditions. Furthermore, aged MPs had a more pronounced effect on these indicators compared to virgin MPs in saline soil. Therefore, MPs in soil poses a potential risk for biota's uptake of SDZ, particularly in fragile environment. Moreover, the risk intensifies with aged MPs.

Interactions of traditional and biodegradable microplastics with neonicotinoid pesticides

Neonicotinoid pesticides (NNPs) and microplastics (MPs) are two emerging contaminants in agricultural environment. However, the interaction between MPs (especially biodegradable plastics) and NNPs is currently unclear. Therefore, taking thiacloprid (THI) as an example of NNPs, this study explores the adsorption-desorption process and mechanism of NNPs on MPs (traditional and biodegradable plastics), and analyzed the main factors affecting the adsorption (pH, salinity and dissolved organic matter). In addition, by using diffusive gradients in thin-films device, this study assessed the impact of MPs on the bioavailability of NNPs in soil. The results showed that the maximum adsorption capacity of polyamide 6 (96.49 μg g-1) for THI was greater than that of poly (butylene adipate co-terephthalate) (88.78 μg g-1). Aging increased the adsorption amount of THI (5.53 %-15.8 %) due to the higher specific surface area and reduced contact angle of MPs, but the adsorption mechanism remained unchanged. The desorption amount of THI from MPs in simulated intestinal fluid is 1.30-1.36 times. The MPs in soil alter the distribution of THI in the soil, increasing the bioavailability of THI while inhibiting its degradation. The results highlighted the significance of examining the combined pollution caused by MPs and NNPs.

Role of UV radiation and oxidation on polyethylene micro- and nanoplastics: impacts on cadmium sorption, bioaccumulation, and toxicity in fish intestinal cells

This study investigated the role of ultraviolet (UV) radiation and oxidation in high-density polyethylene microplastics (2-15 μm) and nanoplastics (0.2-9.9 μm) (NMPs) on particle chemistry, morphology, and reactivity with cadmium (Cd). Additionally, toxicity of NMPs alone and with Cd was evaluated using RTgutGC cells, a model of the rainbow trout (Oncorhynchus mykiss) intestine. The role on NMPs on Cd bioaccumulation in RTgutGC cells was also evaluated. Dynamic light scattering indicated that after UV radiation NPs agglomerated size increased from 0.8 to 28 µm, and to 8 µm when Cd was added. Oxidized MPs agglomerated size increased from 11 and 7 to 46 and 27 µm in non-UV- and UV-aged oxidized MPs when adding Cd, respectively. Cd-coated particles exhibited generally significantly higher zeta potential than non-Cd-coated particles, while attenuated total reflectance-Fourier transform infrared spectroscopy showed that the functional chemistry of the particles was oxidized and modified after being exposed to UV radiation. Presence of NMPs resulted in a significant decrease in Cd bioaccumulation in RTgutGC cells (100.5-87.9 ng Cd/mg protein) compared to Cd alone (138.1 ng Cd/mg protein), although this was not quite significant for co-exposures with UV-aged NPs (105.7 ng Cd/mg protein). No toxicity was observed in RTgutGC cells exposed to NMPs alone for 24 h. Moreover, co-exposures with Cd indicated that NMPs reduce the toxicity of Cd. Altogether these results show that UV aging enhances NMP surface reactivity, increasing Cd absorption in solution, which resulted in a reduction in Cd bioavailability and toxicity.

Adsorption properties and mechanism of Cu(II) on virgin and aged microplastics in the aquatic environment

Microplastics (MPs) migrate by adsorbing heavy metals in aquatic environments and act as their carriers. However, the aging mechanisms of MPs in the environment and the interactions between MPs and heavy metals in aquatic environments require further study. In this study, two kinds of materials, polyamide (PA) and polylactic acid (PLA) were used as target MPs, and the effects of UV irradiation on the physical and chemical properties of the MPs and the adsorption behavior of Cu(II) were investigated. The results showed that after UV irradiation, pits, folds and pores appeared on the surface of aged MPs, the specific surface area (SSA) increased, the content of oxygen-containing functional groups increased, and the crystallinity decreased. These changes enhanced the adsorption capacity of aged MPs for Cu(II) pollutants. The adsorption behavior of the PA and PLA MPs for Cu(II) conformed to the pseudo-second-order model and Langmuir isotherm model, indicating that the monolayer chemical adsorption was dominant. The maximum amounts of aged PA and PLA reached 1.415 and 1.398 mg/g, respectively, which were 1.59 and 1.76 times of virgin MPs, respectively. The effects of pH and salinity on the adsorption of Cu(II) by the MPs were significant. Moreover, factors such as pH, salinity and dosage had significant effects on the adsorption of Cu(II) by MPs. Oxidative complexation between the oxygen-containing groups of the MPs and Cu(II) is an important adsorption mechanism. These findings reveal that the UV irradiation aging of MPs can enhance the adsorption of Cu(II) and increase their role as pollutant carriers, which is crucial for assessing the ecological risk of MPs and heavy metals coexisting in aquatic environments.

Adsorption characteristics of ciprofloxacin hydrochloride on polystyrene microplastics in freshwater

In order to reveal the adsorption mechanism of microplastics (MPs) on antibiotics, polystyrene (PS) was chosen as a typical microplastic, Fenton and high-temperature aging methods were used to obtain aged MPs particles. The adsorption behavior and mechanism of ciprofloxacin hydrochloride (CIP) on PS before and after aging were studied by batch adsorption experiments, and other influencing environmental conditions were evaluated concurrently. The results showed that the adsorption of CIP on PS was an exothermic reaction, the pseudo-second-order model and Freundlich isothermal models could fit the adsorption of CIP on PS. Aging treatment enhanced the adsorption capacity of PS to CIP, and Fenton aging for 7 days had the best effect. The highest adsorption was observed when the solution pH was 6. The adsorption capacity of microplastics gradually decreased with increasing ionic strength and the concentration of fulvic acid, while the aging microplastics changed little with the concentration of fulvic acid. The presence of both Cu (II) and CIP inhibits the adsorption of each other on microplastics. Based on the above findings, the adsorption of CIP on PS is dominated by physical adsorption, and electrostatic interactions and hydrogen bonding interactions are also important mechanisms for the adsorption of CIP on microplastics.

Efficient Extraction and Analysis of Nanoplastics by Ionic Liquid-Assisted Cloud-Point Extraction Coupled with Electromagnetic Heating Pyrolysis Mass Spectrometry

Nanoplastics have attracted much attention due to their potential hazards. However, analysis of nanoplastics remains challenging. In this study, ionic liquid-assisted cloud-point extraction (IL-assisted CPE) was developed to enrich nanoplastics in the aqueous environment and further coupled with electromagnetic heating pyrolysis mass spectrometry. The use of trace ILs improves the extraction efficiency of CPE for nanoplastics. The effects of ILs (types, contents), nanoplastic properties (type, size), and environmental factors (aging time, humic acid content) were systematically investigated to evaluate the applicability. The limits of detection of poly(methyl methacrylate) (PMMA) and polystyrene (PS) were determined to be 1.78 and 2.67 μg/L, respectively. Real environmental samples including lake water, rainwater, and influent and effluent from wastewater treatment plant were analyzed with good accuracy (79.58-116.87%) and satisfactory precision (RSD ≤ 11.99%). A possible mechanism for ILs being absorbed into the ordered surfactant micellar and generating larger micelles to synergically enclose hydrophobic nanoplastics was proposed. This work provides a simple and efficient approach to the extraction and analysis of nanoplastics in aqueous environments.

Adsorption behavior and interaction mechanism of microplastics with typical hydrophilic pharmaceuticals and personal care products

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are two types of emerging contaminants widely present in the global aquatic ecosystem. The ecological risks associated with the coexistence of these two contaminants have garnered increasing attention from researchers. In this study, we selected 15 typical hydrophilic PPCPs, including Sulfacetamide (SA), Thiamphenicol, Florfenicol, Chloramphenicol (CHL), Ampicillin, Cephalexin, Ofloxacin, Fluorouracil, Phenytoin, Theophylline, Cimetidine, Methylparaben, Diethyltoluamide, Benzophenone-2 (BP-2), and Benzophenone-4, as adsorbates. We evaluated the adsorption potential of five traditional plastics (TPs), namely Polyamide 6 (PA6), Polystyrene (PS), Polyethylene terephthalate (PET), Polyvinyl chloride (PVC), and Polyurethane (TPU), as well as three biodegradable plastics (BDPs), including Polylactic acid (PLA), Polybutylene succinate (PBS), and Poly (ε-caprolactone) (PCL), for these adsorbates. Out of the 120 combinations of MPs and PPCPs tested, only 24 exhibited significant adsorption behavior. Notably, the adsorption performance of the three BDPs was stronger than that of the three typical TPs (PS, PET, and PVC). Based on their adsorption potential, PA6, BDPs, phenytoin, and BP-2 were identified as potential sources of high ecological risk. To further explore the adsorption mechanism, we investigated the adsorption behaviors of SA, BP-2, and CHL on PA6. The conclusions were as follows: SA, BP-2, and CHL all reached adsorption equilibrium within 24 h, with the partition coefficient (Kd) following this order: BP-2 (8.051) ≫ SA (0.052) > CHL (0.018). The primary forces of adsorption were electrostatic interactions, intermolecular hydrogen bonding, and hydrophobic interaction, respectively. Additionally, weak electrostatic effects were observed in the adsorption of CHL and BP-2. The effects of pH, ionic strength, and fulvic acid on adsorption capacity varied. These results highlight a complex adsorption mechanism between MPs and hydrophilic contaminants in the aquatic environment. This study provides a basis for further evaluating the ecological risks of MPs and PPCPs combined pollution.

Bidimensional Dynamic Magnetic Levitation: Sequential Separation of Microplastics by Density and Size

There is a current gap in sample preparation techniques integrating the separation of microplastics according to their different material types and particle sizes. We describe herein the Bidimensional Dynamic Magnetic Levitation (2D-MagLev) technique, enabling the resolution of mixtures of microplastics sorting them by plastic type and particle size. Separations are carried out in a bespoke flow cell sandwiched between two ring magnets and connected to programmable pumps for flow control. The first separation dimension is based on sequential increases in the concentration of a paramagnetic salt (MnCl2), enabling magnetic levitation of microplastics with determined densities. The second dimension is based on increasing flow rate gradients and maintaining constant MnCl2 concentrations. This fractionates the magnetically levitating microplastics according to their different particle sizes. Microplastics are therefore collected by their increasing density, and the particles corresponding to each density are fractionated from smaller to larger size. Using polyethylene microspheres with defined density (1.03-1.13 g cm-3) and size (98-390 μm) as microplastic mimicking materials, we investigated their optimum threshold velocities for their size fractionation, potential effects of medium viscosity and sample loading, and types of flow rate gradients (linear, step). Performing a separation using a combination of step gradients in both MnCl2 concentration and flow rate, mixtures comprising microplastics of two different densities and three different particle sizes were separated. 2D-MagLev is simple, fast, versatile, and robust, opening new avenues to facilitate the study of the environmental presence and impact of microplastics.

The adsorption and its mechanism of venlafaxine by original and aged polypropylene microplastic and the changes of joint toxicity

Conjugation with the increment of consumption of polypropylene (PP) masks and antidepressants during pandemic, PP microplastics (MPs) and Venlafaxine (VEN) widely co-existed in surface waters. However, their environmental fate and the combined toxicity were unclear. Hence, we investigated the adsorption behaviors, and associated mechanisms of PP MPs for VEN. The impact factors including pH, salinity, and MPs aging were estimated. The results indicated PP MPs could adsorb amount of VEN within 24 h. The pseudo second-order kinetic model (R2 = 0.97) and Dubinin-Radushkevich model (R2 = 0.89) fitted well with the adsorption capacity of PP MPs for VEN, implying that chemical adsorption accompanied by electrostatic interaction might be the predominant mode for the interactions between PP MPs and VEN. Meanwhile, the adsorption capacity of PP MPs declined from pH of 2.5-4.5 and then increased from 4.5 to 9.5. The increased salinity (5-35 ppt) significantly suppressed the adsorption capacity. Aging by sunlight and UV triggered the formation of new functional group (carbonyl) on MPs, and then enhanced the adsorption capacity for VEN. Gaussian Model analysis further evidenced the electrostatic adsorption occurring in PP MPs and VEN. The combined exposure to PP MPs and VEN showed significantly antagonistic toxicity on Daphnia magna. The adsorption of VEN by PP MPs mitigated the lethal effects and behavioral function impairment posed by VEN on animals, implying the potential protective effects on zooplankton by PP MPs. This study for the first time provides perspective for assessing the environmental fate of MPs and antidepressants in aquatic system.

Characterization of the microplastic photoaging under the action of typical salt ions of biological nitrogen removal processes

Microplastics (MPs) are one of the most prevalent and diverse contaminants, and wastewater treatment plants are significant MP aggregators. Controlling the pollution caused by microplastics requires an understanding of how they age. The properties of the MPs photoaging process under the influence of salt ions typical of biological nitrogen elimination processes were disclosed in this work. The aging process of polyvinyl chloride microplastics (PVC-MPs) was greatly slowed down by greater HCO3- and NO2- concentrations, according to a comparison of the carbonyl index changes that occurred during photoaging. The carbonyl index had a negative correlation with the thermal stability of the photo-aged PVC-MPs, and aging accelerated the elimination of chlorine from the water. The samples were aged by UV radiation after 36 h at 40 °C, and the amount of chlorine eliminated was 10.13 times greater than that of the original MPs samples. It was discovered that the leachate concentration of aged MPs dramatically increased with decreasing particle size and was positively connected with the level of aging by comparing the concentration of leachate for two particle sizes (1 mm and 100 m). Photoaging caused MPs to become rougher, which in turn improved the NO3--N, NH4+-N, and NO2--N adsorption by PVC-MPs.

A comprehensive review on the source, ingestion route, attachment and toxicity of microplastics/nanoplastics in human systems

Microplastics (MPs)/nanoplastics (NPs) are widely found in the natural environment, including soil, water and the atmosphere, which are essential for human survival. In the recent years, there has been a growing concern about the potential impact of MPs/NPs on human health. Due to the increasing interest in this research and the limited number of studies related to the health effects of MPs/NPs on humans, it is necessary to conduct a systematic assessment and review of their potentially toxic effects on human organs and tissues. Humans can be exposed to microplastics through ingestion, inhalation and dermal contact, however, ingestion and inhalation are considered as the primary routes. The ingested MPs/NPs mainly consist of plastic particles with a particle size ranging from 0.1 to 1 μm, that distribute across various tissues and organs within the body, which in turn have a certain impact on the nine major systems of the human body, especially the digestive system and respiratory system, which are closely related to the intake pathway of MPs/NPs. The harmful effects caused by MPs/NPs primarily occur through potential toxic mechanisms such as induction of oxidative stress, generation of inflammatory responses, alteration of lipid metabolism or energy metabolism or expression of related functional factors. This review can help people to systematically understand the hazards of MPs/NPs and related toxicity mechanisms from the level of nine biological systems. It allows MPs/NPs pollution to be emphasized, and it is also hoped that research on their toxic effects will be strengthened in the future.

A Latest Review on Micro- and Nanoplastics in the Aquatic Environment: The Comparative Impact of Size on Environmental Behavior and Toxic Effect

Micro and nanoplastics (MNPs) have attracted growing global research attention due to their distinct environmental impacts, addressing escalating concerns. The diverse materials, sizes, and shapes of MNPs result in a range of environmental impacts. Size, a crucial characteristic of MNPs, influences their environmental behavior, affecting processes like migration, sedimentation, aggregation, and adsorption. Moreover, size modulates the biodistribution and toxicity of MNPs in aquatic organisms. This review delves into the comprehensive impacts of plastic size, with a primary focus on environmental behavior and toxic effects. Ultimately, this review emphasizes the ecological implications of MNP size, laying a foundation for future research in this field.

Coupled adsorption-photocatalysis process for the removal of diclofenac using magnetite/reduced graphene oxide nanocomposite

Diclofenac (DCF) is frequently detected in water bodies (ng/L to g/L) as it is not completely removed by conventional wastewater treatment plants. Adsorption and photocatalysis have been studied as promising methods for treating DCF; however, both processes have limitations. Thus, in this study, the removal efficiency of DCF is evaluated using a magnetite/reduced graphene oxide (Fe3O4/RGO) nanocomposite via a coupled adsorption-catalysis process. The Fe3O4/RGO nanocomposite was successfully synthesized using a microwave-assisted solvothermal method and exhibited a bandgap of 2.60 eV. The kinetic data best fitted the Elovich model (R2 = 0.994, χ2 = 0.29), indicating rapid adsorption. The maximum DCF adsorption capacity calculated using the Langmuir model was 80.33 mg/g. An ultraviolet C (UVC) light source and 0.1 g/L of Fe3O4/RGO nanocomposite were the optimum conditions for the removal of DCF (C0 = 30 mM) by a coupled adsorption-photocatalysis process (first-order rate constant (k) = 0.088/min), which was greater than the single adsorption (k = 0.029/min) and pre-adsorption and post-photocatalysis (k = 0.053/min) processes. This indicates that the adsorbed DCF did not hamper the photocatalytic reaction of the Fe3O4/RGO nanocomposite, but rather enhanced the coupled adsorption-photocatalytic reaction. DCF removal efficiency was higher at acidic conditions (pH 4.3-5.0), because high H+ promotes the generation of certain reactive oxygen species (ROS) and increases of electrostatic interaction. The presence of NaCl and CaCl2 (10 mM) did not notably affect the total DCF removal efficiency; however, Ca2+ affected the initial DCF adsorption affinity. Scavenger experiments demonstrated O2∙- and h+ play a key ROS than ·OH to degrade DCF. The acute toxicity of DCF towards Aliivibrio fischeri gradually decreased with increasing treatment time.

Natural aging and adsorption/desorption behaviors of polyethylene mulch films: Roles of film types and exposure patterns

Polyethylene (PE) mulch films are an important source of microplastics (MPs) in agricultural soils, which may further affect the bioavailability of coexisting pollutants. In this study, white (WM), black (BM), and silver-black (SM) PE mulch films were aged on the soil surface and under soil burial to simulate the two exposure patterns of abandoned mulch films in the field. Results indicated that the soil-surface exposure induced more pronounced aging characteristics, and WM seemed the most susceptible. Serious surface deterioration by aging led to a drastic decrease in the tensile properties of the films, suggesting the tendency to fragment. Oxygen-containing functional groups were generated on the film surfaces, with oxygen/carbon ratios increasing by up to 29 times, which contributed to the prominent increase in Pb adsorption on the film-derived MPs. Additionally, the film surface became more hydrophobic when exposed to the soil surface but more hydrophilic in the soil-burial exposure, which was in agreement with the change in triclosan adsorption, i.e., promotion and suppression, respectively. Aging generally decreased the desorption potential of the adsorbed pollutants in simulated gastrointestinal solutions due to increased interactions. By comparison, exposure patterns were revealed to be the critical factor for these changes, regardless of film types.

Nanoscale-controlled organicinorganic hybrid spheres for comprehensive enrichment of ultratrace chlorobenzenes in marine and fresh water

The size of the adsorbent has the potential to influence extraction performance, but the size effect at the nanoscale is still poorly understood. In this study, organic-inorganic hybrid nanospheres (OIHNs) with controllable nanoscale sizes of 30, 50, and 100 nm were successfully prepared. These materials were further fabricated as solid phase microextraction (SPME) coatings with similar thicknesses, and coupled with gas chromatography-mass spectrometry (GC-MS) to investigate their extraction performance. The results showed that the extraction capacities of OIHNs for chlorobenzenes (CBs) and polycyclic aromatic hydrocarbons (PAHs) were much better than those of their corresponding derived carbon materials, despite the smaller specific surface areas and lower porosities of them. In addition, the enrichment performance increased significantly with decreasing particle size, and the OIHN-30 coating demonstrated the best performance, with enrichment factors ranging from 1098 to 6853 for CBs. Finally, a highly sensitive and practical analytical method was established with a wide linear range of 0.5-5000 ng·L-1, and the limits of quantification (LOQs) were 0.43-1.7 ng·L-1. The determinations of ultratrace CBs in five marine water samples and five fresh water samples were realized successfully. This study is expected to contribute to a deep understanding of the environmental effects of nanoparticles and the design of high-performance adsorbents.

Microplastic pollution in terrestrial ecosystems: Global implications and sustainable solutions

Microplastic (MPs) pollution has become a global environmental concern with significant impacts on ecosystems and human health. Although MPs have been widely detected in aquatic environments, their presence in terrestrial ecosystems remains largely unexplored. This review examines the multifaceted issues of MPs pollution in terrestrial ecosystem, covering various aspects from additives in plastics to global legislation and sustainable solutions. The study explores the widespread distribution of MPs worldwide and their potential antagonistic interactions with co-occurring contaminants, emphasizing the need for a holistic understanding of their environmental implications. The influence of MPs on soil and plants is discussed, shedding light on the potential consequences for terrestrial ecosystems and agricultural productivity. The aging mechanisms of MPs, including photo and thermal aging, are elucidated, along with the factors influencing their aging process. Furthermore, the review provides an overview of global legislation addressing plastic waste, including bans on specific plastic items and levies on single-use plastics. Sustainable solutions for MPs pollution are proposed, encompassing upstream approaches such as bioplastics, improved waste management practices, and wastewater treatment technologies, as well as downstream methods like physical and biological removal of MPs. The importance of international collaboration, comprehensive legislation, and global agreements is underscored as crucial in tackling this pervasive environmental challenge. This review may serve as a valuable resource for researchers, policymakers, and stakeholders, providing a comprehensive assessment of the environmental impact and potential risks associated with MPs.

Adsorption behavior of triclosan on polystyrene nanoplastics: The roles of particle size, surface functionalization, and environmental factors

Nanoplastics (NPs) contribute substantially to the transport of waterborne pollutants. Triclosan (TCS) has a high potential to contact with NPs because of their prevalence in natural waters. Herein, this study investigated the adsorption behavior of TCS on differently sized and functionalized polystyrene (PS) NPs. The effects of environmental factors such as pH, salinity, and dissolved organic matter (DOM) were also evaluated. Results suggest that the adsorption equilibrium constant (kd) of TCS in pristine PSNP suspensions followed the order as: PSNPs-50 nm (4.39 L·g-1) > PSNPs-100 nm (2.78 L·g-1) > PSNPs-200 nm (2.59 L·g-1) > PSNPs-500 nm (1.36 L·g-1) ≈ PSNPs-900 nm (1.36 L·g-1). For the functionalized PSNPs (i.e., PSNPs-COOH, PSNPs-NH2), the values of specific surface area normalized kd called kd, SSA were higher than those of pristine PSNPs. Meanwhile, TCS adsorption on two functionalized PSNPs remained stable and then decreased as salinity increased, while an opposite trend was observed toward pristine PSNPs. All these suggested that physicochemical properties of PSNPs (e.g., particle size and surface functional groups) are important factors influencing their adsorption capacity. When the solution pH raised, the adsorbed amounts of TCS on all tested PSNPs prone to decline. However, DOM only affected the adsorption behavior of PSNPs-50 nm, probably owing to its aggregation with tiny PSNPs and the induced secondary adsorption.

Small microplastic particles promote tetracycline and aureomycin adsorption by biochar in an aqueous solution

Biochar (BC) has been used to remove antibiotics from wastewater. Microplastics are emerging contaminants of wastewater. The capacities of microplastics for adsorbing antibiotics and the effects of microplastics of different types and particle sizes on antibiotic adsorption by BC have not been studied. Here, adsorption isotherm and kinetics experiments were performed to investigate tetracycline and aureomycin adsorption to polyvinyl chloride particles with diameters of 10, 100, 500, and 2000 μm, polylactic acid particles with diameters of 30, 100, 500, and 2000 μm (PLA30, PLA100, PLA500, and PLA2000, respectively), and wheat straw BC. The highest tetracycline adsorption capacity (25.00 mg g-1) was found for a PLA30 + BC. The tetracycline adsorption capacities of the other microplastic particles were 20.44-24.57 mg g-1. The highest aureomycin adsorption capacity (39.50 mg g-1) was found for 10 μm polyvinyl chloride particles and BC. The aureomycin adsorption capacities of the other microplastic particles were 32.21-38.42 mg g-1. The tetracycline adsorption capacities were 13.69%, 6.28%, 5.49%, and 4.54% higher for PLA30 + BC, PLA100 + BC, PLA500 + BC, and PLA2000 + BC, respectively, than for only BC. This may have been because there were more sites available per unit mass of microplastic for adsorbing tetracycline and dissolved organic carbon on small microplastic particles than large microplastic particles. The results indicated that microplastics can adsorb antibiotics and increase the amounts of antibiotics adsorbed by BC. Therefore, it is essential to consider potential interactions between BC and microplastics when BC is used to remove antibiotics from wastewater.

Effective triclosan removal by using porous aromatic frameworks in continuous fixed-bed column studies

Triclosan (TCS) has been regarded as an emerging contaminant in aquatic systems, making its efficient removal of great significance. In this study, NPVMo@iPAF-1, with a specific surface area of 665 m2/g, was prepared by incorporating (NH4)5H6PV8Mo4O40 into porous aromatic frameworks (PAF). The maximum adsorption capacity of TCS on NPVMo@iPAF-1 reached 917.1 mg/g, as calculated from the Langmuir model. Fixed-bed columns packed with NPVMo@iPAF-1 were employed for TCS removal; the experiment data strongly correlated with the Thomas and Yoon-Nelson models under different operational conditions. Pore preservation, electrostatic effects, and the synergistic effect of π-π interactions contributed to the effective adsorption of TCS onto NPVMo@iPAF-1. The NPVMo@iPAF-1 fixed-bed column could be effectively regenerated through in-situ ozonation for more than 10 regeneration cycles. NPVMo@iPAF-1 turned out to be a promising adsorbent for removing TCS not only from pure water but also from reclaimed water and surface water samples.

Ecotoxicological effects of antibiotic adsorption behavior of microplastics and its management measures

Microplastics adsorb heavy metals and organic pollutants to produce combined pollution. Recently, the adsorption behavior of antibiotics on microplastics has received increasing attention. Exploring the sorption behavior of pollutants on microplastics is an important reference in understanding their ecological and environmental risk studies. In this paper, by reviewing the academic literature in recent years, we clarified the current status of research on the adsorption behavior of antibiotics on microplastics, discussed its potential hazards to ecological environment and human health, and summarized the influence of factors on the adsorption mechanisms. The results show that the adsorption behavior of antibiotics on microplastics is controlled by the physical and chemical properties of antibiotics, microplastics, and water environment. Antibiotics are adsorbed on microplastics through physical and chemical interactions, which include hydrophobic interaction, partitioning, electrostatic interaction, and other non-covalent interactions. Intensity of adsorption between them is mainly determined by their physicochemical properties. The basic physicochemical properties of the aqueous environment (e.g., pH, salinity, ionic strength, soluble organic matter content, and temperature) will affect the physicochemical properties of microplastics and antibiotics (e.g., particle size, state of dispersibility, and morphology), leading to differences in the type and strength of their interactions. This paper work is expected to provide a meaningful perspective for better understanding the potential impacts of antibiotic adsorption behavior of microplastics on aquatic ecology and human health. In the meantime, some indications for future related research are provided.

First evidence of microplastics in the water and sediment of Surakarta city river basin, Indonesia

The main aim of this study was to assess the presence of microplastics in the water and sediments of the Surakarta city river basin in Indonesia. In order to accurately reflect the river basin, a deliberate selection process was employed to choose three separate sampling locations and twelve sampling points. The results of the study revealed that fragments and fibers were the primary types of microplastics seen in both water and sediment samples. Furthermore, a considerable percentage of microplastics, comprising 53.8 % of the total, had dimensions below 1 mm. Moreover, the prevailing hues identified in the water samples were blue and black, comprising 45.1 % of the overall composition. In contrast, same color categories accounted for 23.3 % of the microplastics found in the soil samples. The analysis of microplastic polymers was carried out utilizing ATR-FTIR spectroscopy, which yielded the identification of various types including polystyrene, silicone polymer, polyester, and polyamide.

Adsorption-desorption behaviors of ciprofloxacin onto aged polystyrene fragments in aquatic environments

As two emerging pollutants of great concern, microplastics (MPs) and antibiotics inevitably cooccur in various aquatic environments and interact with each other, impacting the fate and ecological risks. Aging obviously complicates their interaction and deserves further study. Therefore, the adsorption-desorption behaviors of ciprofloxacin (CIP) onto polystyrene (PS) fragments with various aging extent were investigated, and the key physiochemical properties influencing the interaction and the interaction mechanisms were clarified by redundancy analysis, FTIR and XPS spectra. The physicochemical properties of PS MPs were significantly changed with aging time, and the morphological and chemical changes seemed to occur asynchronously. The adsorption of CIP onto the pristine PS MPs relied on physisorption, especially the ion-involving electrostatic and cation-π interaction. Due to the hydrogen bonding formed by the C-OH, CO, and O-CO groups of PS and CIP, the adsorption capacities of the aged PS MPs were greatly increased. The desorption efficiency of CIP from MPs in the gastric fluid was closely related to the solution ionic strengths, C-OH and CO groups of MPs, while that in the intestinal fluid was associated with O-CO groups of MPs. The different impact factors could be well described by the differences in the chemical components and pHs of the simulated gastric and intestinal fluids. This study gives a comprehensive understanding of the adsorption-desorption behaviors of antibiotics onto MPs at a molecular level and indicates that MPs could act as Trojan horses to transport antibiotics into aquatic organisms.

Sorption behaviour of tebuconazole on microplastics: kinetics, isotherms and influencing factors

Microplastics (MPs) and pesticides are two classes of environmental pollutants and have become global challenges. MPs could adsorb substantial environmental pollutants, which may affect their transportation, distribution and cause combination toxicity. Therefore, the study of sorption properties and mechanisms is the basis of the ecological risk assessment of co-exposure of pesticides and MPs. In this research, typical triazole fungicide tebuconazole (TEB) is selected as a model pollutant, and its sorption behaviour was investigated by kinetic and isotherm models. Meanwhile, a series of environmental influencing factors, like pH, salinity, and metals were conducted. Results showed that the sorption of TEB on MPs could reach equilibrium at 24 h, and the sorption capacity followed the order of PA (polyamide) > PS (polystyrene) > PP (polypropylene). The pseudo-second-order model was the most appropriate model to describe kinetic data, and the Freundlich model was well fit for PA sorption isotherms, in contrast the Langmuir model is better for PP and PS. Additionally, the pH of the solution, salinity, and metals have an important effect on sorption. Combined with Fourier Transform Infrared Spectroscopy and environmental influencing factors, the sorption mechanisms were mainly electrostatic interaction and hydrogen bond for PA and PP, and hydrophobic force, intermolecular force, and electrostatic force for PS, respectively.

Longitudinal and vertical distribution of microplastics in various pipe scales in an operating drinking water distribution system

Microplastics (MPs) are ingested by humans through the daily consumption of drinking water. Pipe scales are recognized as important sites of MPs occurrence in the drinking water distribution system (DWDS). Despite extensive research on drinking water, no study has been conducted to investigate the distribution of MPs in pipe scales within an operational DWDS. The underground placement of DWDSs brings challenges for sampling pipe scales. In this study, 5 tap water and 16 pipe scales samples were collected from a typical DWDS. The analysis of MPs abundance in these 21 samples filled the data gap in the distribution of MPs in both pipe scales and tap water along the DWDSs. MPs were detected in all water samples (1.74-20.88 MPs/L) and pipe scales samples (0.03-3.48 MPs/cm2). In tap water, MPs abundance increased abruptly in the stagnant-slow flow region and reached the maximum value (20.88 MPs/L), even surpassing the abundance in raw water (6.42 MPs/L). In the pipe scales, MPs abundance decreased from the upstream to downstream of DWDS and was associated with the heavy metal concentration. MPs smaller than 150 µm accounted for 91.6% of the tap water (21-971 µm) and pipe scales (20-2055 µm). The abundance of MPs showed a logarithmic increase as the size decreased. The proportion of MPs fibers in tap water was lower than that in pipe scales. A total of 35 MPs polymers were detected, with 34 polymers in pipe scales and 26 polymers in tap water. In terms of abundance, polyethylene terephthalate (50.0%) was the dominant polymer in pipe scales, while polyamide (70.3%) was the dominant polymer in tap water. Regarding detection rate, polyamide was detected in all 21 samples, followed by polyurethane in 19 samples. The distribution of MPs along the longitudinal direction of the DWDS was correlated with heavy metal. While the distribution of MPs in the vertical direction of large diameter pipe scales was dependent on their sizes, and densities. The greatest abundance, size and density of MPs were detected at the bottom 120-degree.