Nanoplastics: From model materials to colloidal fate

Metal-free AAO membranes function as both filters and Raman enhancers for the analysis of nanoplastics

Nanoplastics (NPs) are growing concerns for health and the environment, being widely distributed across marine, freshwater, air, and biological systems. Analyzing NPs in real environmental samples requires pretreatment, which has traditionally been complex and often leads to underestimation in actual samples, creating a gap between real-world conditions and research findings. In this study, we propose using anodic aluminum oxide (AAO) membrane as a direct Raman substrate for particles on a filter, achieving complete recovery during separation and concentration while simplifying the pretreatment stages. Moreover, our study introduces AAO itself, without any metal coating, as a normal Raman spectroscopy substrate with strong Raman signal enhancement for NPs and an ultra-flat surface for rapid analysis. By using AAO with nanometer-sized pores, we effectively detected standard polystyrene spherical particles on the AAO membrane down to 200 nm. Our investigation extended to irregular NPs containing PP, PE, PET, PS, PMMA, and PLA, confirming the reliability of this approach. Our results suggest that employing an AAO membrane with dual functionality as both a filter and a Raman substrate effectively serves as a cost-effective, rapid, simple, and accurate tool for NP analysis in complex environments.

Incognito forms of polyethylene small micro and nanoplastics in solvents: Changes in molecular vibrations

Plastic particles in the range of 1 nm to 1 μm in diameter are nano pollutants in all environments, ubiquitous throughout the air, all waters and living organisms. The formation of nanoplastics (NP) occurs in different ways that include material abrasion, light exposure and even from normal use of plastic materials. In solvents, NP and small microplastics (< 10 μm diameter) differ from larger plastic particles in that they can mix and suspend, similar to other colloidal sized particles. In this study, we used normal mixing conditions and our novel solubilization method to generate polyethylene (PE) small microplastic and nanoplastic solutions (sM&NP), both in water and in common organic solvents. The sM&NP were examined using Raman spectroscopy and microscopy, transmission electron microscopy (TEM) and particle size analysis using dynamic light scattering (DLS) methods. The Raman data showed notable spectral changes compared to solid PE, which indicates significant molecular and morphological changes of the PE polymer when it is part of these sM&NP solutions or suspensions. In organic solvents, the spectral changes for sM&NP signified a loss of polymer crystallinity, while the changes in aqueous solutions suggest greater molecular reorganization of the polymer structure. These structural changes were supported by TEM images of the particles that appeared mostly amorphous with varying thickness. Importantly, the changed spectra of these small particles of PE likely render them more difficult to detect and study, particularly in real-world aqueous systems. These findings indicate that solubilized sM&NP are routinely modified by solvent exposure, and thereby interact differently from larger plastic materials, particularly in aqueous environments.

Colloidal stability of UV-aged and protein-coated nanoplastics in natural waters under warming

Nanoplastics, particles smaller than 1000 nm that are produced by degradation of plastic debris, pose an environmental threat and may endanger natural ecosystems and human health. In aquatic environments, the large surface area and high surface energy of NPs facilitate their interactions with the surroundings; thus, understanding their behavior, transport, and fate is essential. In this study, we investigated the individual and combined effects of UV aging and protein coating on the stability of NPs in aquatic environments under elevated temperatures. UV-aged NPs were created via indoor UV lamp exposure, and protein coating was achieved by introducing bovine serum albumin (BSA). Sequential processes produced UV + BSA and BSA + UV-coated NPs for comprehensive analysis. Aggregation kinetics and stability were examined in electrolyte solutions (NaCl and CaCl2) and natural waters. Results indicated that BSA coating improved the colloidal stability of NPs in electrolyte solutions by promoting steric repulsion, a trend observed in rivers, lakes, and seawater but not in groundwater. Sequential UV aging after BSA coating caused protein denaturation, reducing the stability of NPs. Additionally, increased temperatures led to a greater level of NP aggregation due to lower energy barriers. These findings highlight UV aging, protein coating, and temperature as critical factors influencing the behavior and fate of NPs in natural environments.

Polystyrene nanoplastics impact the bioenergetics of developing zebrafish and limit molecular and physiological adaptive responses to acute temperature stress

Plastic pollution is a growing environmental concern due to its ubiquitous impact on aquatic ecosystems. Nanoplastics can be generated from the breakdown of plastic waste and interact with organisms at the cellular level, potentially disrupting cellular physiology. We investigated the effects of 44 nm polystyrene nanoparticles (44 nm NanoPS) on the development and physiology of zebrafish (Danio rerio) in the presence of sublethal heat stress (32 °C vs control, 28 °C). We hypothesized that the simultaneous exposure to nanoplastics and rising temperatures seriously threaten developing fish. This combination could create a critical imbalance: rising temperatures may lead to heightened energy demands, while nanoplastic exposure reduces energy production, threatening animal survival. As expected, 32 °C increased markers associated with animal metabolism and developmental timing, such as growth, hatching, heart rate, and feeding. Changes in apoptosis dynamics, oxygen consumption rates, and a decrease in mitochondrial content were detected as adaptive processes to temperature. 44 nm NanoPS alone did not alter development but decreased mitochondrial efficiency in ATP production and increased apoptosis in the heart. Surprisingly, exposure to 44 nm NanoPS at 32 °C did not cause major implications to survival, developmental success, or morphology. Still, 44 nm NanoPS mitigated the temperature-driven change in heart rate, increased oxidative stress, and decreased the coupling efficiency of the less abundant and highly active mitochondria under heat stress. We highlight the interplay between temperature and nanoplastics exposure and suggest that the combined impact of nanoplastics and temperature stress results in a scenario where physiological adaptations are strained, potentially leading to compromised development. This research underscores the need for further investigation into the metabolic costs of plastic pollution, particularly in the context of global warming, to better understand its long-term implications for aquatic life.

Microplastics in Agricultural Crops and Their Possible Impact on Farmers' Health: A Review

The indiscriminate use of plastic products and their inappropriate management and disposal contribute to the increasing presence and accumulation of this material in all environmental zones. The chemical properties of plastics and their resistance to natural degradation lead over time to the production of microplastics (MPs) and nanoplastics, which are dispersed in soil, water, and air and can be absorbed by plants, including those grown for food. In agriculture, MPs can come from many sources (mulch film, tractor tires, compost, fertilizers, and pesticides). The possible effects of this type of pollution on living organisms, especially humans, increase the need to carry out studies to assess occupational exposure in agriculture. It would also be desirable to promote alternative materials to plastic and sustainable agronomic practices to protect the safety and health of agricultural workers.

Ecological fitness impairments induced by chronic exposure to polyvinyl chloride nanospheres in Daphnia magna

The aim of this study was to evaluate the effects of chronic exposure (21 days) to an environmentally relevant concentration (10 μg/L) of two different nanoplastic (NP) polymers on the aquatic model organism Daphnia magna. This study examined the impact of exposure to 200 nm polystyrene nanoplastics (PS-NPs) and polyvinyl chloride nanoplastics (PVC-NPs), which had an average size similar to that of PS-NPs (ranging from 50 nm to 350 nm). The effects of polymer exposure on morphometric parameters, number of molts, swimming behaviour, and reproductive outcomes were evaluated. The findings indicate that PVC exposure induced higher body dimensions, while both polymers resulted in an increase in molting behaviour. Moreover, exposure to PVC-NPs had a negative impact on the reproduction of D. magna, as evidenced by a delay in the day of the first brood, a reduction in the total number of offspring produced, and, consequently, a slower population growth rate. It is hypothesised that the ingestion of PVC-NPs by D. magna may have resulted in an impairment of ecdysone hormone functionality and that the increased moulting events potentially representing an adaptive response to the negative effects of PVC-NP adhesion to the organism's body surfaces. These two organisms' responses could concur to explain the observed effects. This study identified the fitness impairments caused by exposure to PVC-NPs, which can lead to relevant ecological consequences. The comparative analysis of the effects induced by two types of polymers has revealed the generation of disparate hazards to D. magna. Furthermore, the chemical composition appears to be a pivotal factor in the onset of these effects. It can therefore be stated that PS is not a suitable standard for representing the toxicity of all plastics.

Local thermal adaption mediates the sensitivity of Daphnia magna to nanoplastics under global warming scenarios

The toxicity of nanoplastics at environmentally relevant concentrations has received widespread attention in the context of global warming. Despite numerous studies on the impact of mean temperature (MT), the effects of daily temperature fluctuations (DTFs) on the ecotoxicity of nanoplastics remains largely unexplored. Moreover, the role of evolutionary adaptation in assessing long-term ecological risks is unclear. Here, we investigated the effects of polystyrene nanoplastics (5 μg L-1) on Daphnia magna under varying MT (20 °C and 24 °C) and DTFs (0 °C, 5 °C, and 10 °C). Capitalizing on a space-for-time substitution approach, we further assessed how local thermal adaptation affect the sensitivity of Daphnia to nanoplastics under global warming. Our results indicated that nanoplastics exposure in general reduced heartbeat rate, thoracic limb activity and feeding rate, and increased CytP450, ETS activity and Hgb concentrations. Higher MT and DTFs enhanced these effects. Notably, clones originating from their respective sites performed better under their native temperature conditions, indicating local thermal adaptation. Warm-adapted low-latitude D. magna showed stronger nanoplastics-induced increases in CytP450, ETS activity and Hgb concentrations under local MT 24 °C, while cold-adapted high-latitude D. magna showed stronger nanoplastics-induced decreases in heartbeat rate, thoracic limb activity and feeding rate under high MT than under low MT.

Heteroaggregation kinetics of oppositely charged nanoplastics in aquatic environments: Effects of particle ratio, solution chemistry, and interaction sequence

Interactions between positively charged amino-modified (APS) and negatively charged bare (BPS) polystyrene nanoplastics may cause heteroaggregation in aquatic environments. This study investigated the effects of particle concentration ratio, solution chemistry [electrolytes, pH, and natural organic matter (NOM)], and interaction sequence on their heteroaggregation kinetics. In the absence of electrolytes and NOM, the APS/BPS ratio for attaining maximum heteroaggregation rate (khetero) increased from APS/BPS= 3/7 to APS/BPS= 1/1 as pH increased from 4 to 10, indicating that electrostatic interactions dominated heteroaggregation. In the absence of NOM, khetero ranked APS/BPS= 2/3 > APS/BPS= 1/1 > APS/BPS= 3/2. Colloidal stability decreased linearly as pH increased from 4 to 8 at APS/BPS= 1/1, while diffusion-limited heteroaggregation persisted at pH 10. In NaCl solution, humic acid (HA) retarded heteroaggregation more effectively than sodium alginate (SA) via steric hindrance and weakening electrostatic interactions, following the modified Derjaguin-Landau-Verwey-Overbeek (MDLVO) theory. Compared with simultaneous interactions among APS, BPS, NaCl, and NOM, the NOM retardation effects on heteroaggregation weakened if delaying its interaction with others. In CaCl2 solution, the effects of NOM on heteroaggregation depended on counterbalance among charge screening, steric hindrance, and calcium bridging. These findings highlight the important role of heteroaggregation between oppositely charged nanoplastics on their fate and transport in aquatic environments.

The dosage- and size-dependent effects of micro- and nanoplastics in lettuce roots and leaves at the growth, photosynthetic, and metabolomics levels

The occurrence of microplastics (MPs) and nanoplastics (NPs) in soils potentially induce morphological, physiological, and biochemical alterations in plants. The present study investigated the effects of MPs/NPs on lettuce (Lactuca sativa L. var. capitata) plants by focusing on (i) four different particle sizes of polyethylene micro- and nanoplastics, at (ii) four concentrations. Photosynthetic activity, morphological changes in plants, and metabolomic shifts in roots and leaves were investigated. Our findings revealed that particle size plays a pivotal role in influencing various growth traits of lettuce (biomass, color segmentation, greening index, leaf area, and photosynthetic activity), physiological parameters (including maximum quantum yield - Fv/Fmmax, or quantum yield in the steady-state Fv/FmLss, NPQLss, RfdLss, FtLss, FqLss), and metabolomic signatures. Smaller plastic sizes demonstrated a dose-dependent impact on aboveground plant structures, resulting in an overall elicitation of biosynthetic processes. Conversely, larger plastic size had a major impact on root metabolomics, leading to a negative modulation of biosynthetic processes. Specifically, the biosynthesis of secondary metabolites, phytohormone crosstalk, and the metabolism of lipids and fatty acids were among the most affected processes. In addition, nitrogen-containing compounds accumulated following plastic treatments. Our results highlighted a tight correlation between the qPCR analysis of genes associated with the soil nitrogen cycle (such as NifH, NirK, and NosZ), available nitrogen pools in soil (including NO3- and NH4), N-containing metabolites and morpho-physiological parameters of lettuce plants subjected to MPs/NPs. These findings underscore the intricate relationship between specific plastic contaminations, nitrogen dynamics, and plant performance.

Nanopolystyrene size effect and its combined acute toxicity with halogenated PAHs on Daphnia magna

Nanoplastics (NPs, diameter <1 μm) not only have toxicity but also change the toxicity of other pollutants in water. To date, the nanopolystyrene (nano-PS) size effect and its combined toxicity with halogenated polycyclic aromatic hydrocarbons (HPAHs) remain unclear. In this study, the single toxicity, combined toxicity, and mode of action of the binary mixture of polystyrene (PS) and HPAH were examined. At the same time, the nano-PS size effect on combined toxicity was also discussed. According to our results, the 48 h acute toxicity test results showed that 30 nm PS was highly toxic (EC50-48 h = 1.65 mg/L), 200 nm PS was moderately toxic (EC50-48 h = 17.8 mg/L), and 1 μm PS was lowly toxic (EC50-48 h = 189 mg/L). The NP toxicity decreased with increasing size. HPAHs were highly toxic substances to Daphnia magna (EC50-48 h = 0.12-0.22 mg/L). The mode of action of PS and HPAHs was antagonistic according to the toxicity unit method (TU), additive index method (AI), and mixture toxicity index method (MTI). The size effect of nano-PS operates via two mechanisms: the inherent toxicity of nano-PS and the sorption of pollutants by nano-PS. The former impacts the combined toxicity more than the latter. In the binary mixed system, the larger the particle size and the higher the proportion of NPs in the system, the less toxic the system was. Linear interpolation analysis can be used to predict the combined toxicity of a mixed system with any mixing ratio.

Characterization of polyethylene terephthalate (PET) and polyamide (PA) true-to-life nanoplastics and their biological interactions

Plastic and microplastics, including polyethylene (PE), polypropylene (PP), and polystyrene (PS), are major contributors to environmental pollution. However, there is a growing recognition of the need to investigate a wider range of plastic polymers to fully understand the extent and impacts of plastic pollution. This study focuses on the comprehensive characterization of true-to-life nanoplastics (T2LNPs) derived from polyethylene terephthalate (PET) and polyamide (PA) to enhance our understanding of environmental nanoplastics pollution. T2LNPs were produced through cryogenic mechanical fragmentation of everyday items made from these polymers. A solid methodological framework incorporating various characterization techniques was established. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA) were employed to study the chemical composition and confirm the absence of chemical modifications possibly occurring during fragmentation. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the morphology of the T2LNPs. Additionally, AFM image analysis compared to dynamic light scattering (DLS) measurements provided insights into the size distribution and the stability of the T2LNP suspensions. The results revealed the heterogeneity of T2LNPs derived from PET and PA, emphasizing the importance of studying different plastic compositions to comprehensively understand nanoplastics pollution. Lastly, the distinctive characteristics and morphology of T2LNPs were translated into the realm of biological interactions, offering initial insights into the influence of these disparities on the formation of the protein corona on the surface of T2LNPs. By proposing T2LNPs as test materials and establishing a comprehensive characterization approach, this study aims to bridge the knowledge gap regarding the behavior and toxicity of nanoplastics. Furthermore, it highlights the need for a reliable and transferable analytical package for nanoplastic characterization to facilitate future studies on the environmental impact of nanoplastics.

Advancements in Raman imaging for nanoplastic analysis: Challenges, algorithms and future Perspectives

BACKGROUND

While the concept of microplastic (<5 mm) is well-established, emergence of nanoplastics (<1000 nm) as a new contaminant presents a recent and evolving challenge. The field of nanoplastic research remains in its early stages, and its progress is contingent upon the development of reliable and practical analytical methods, which are currently lacking. This review aims to address the intricacies of nanoplastic analysis by providing a comprehensive overview on the application of advanced imaging techniques, with a particular focus on Raman imaging, for nanoplastic identification and simultaneous visualisation towards quantification.

RESULTS

Although Raman imaging via hyper spectrum is a potentially powerful tool to analyse nanoplastics, several challenges should be overcome. The first challenge lies in the weak Raman signal of nanoplastics. To address this, effective sample preparation and signal enhancement techniques can be implemented, such as by analysing the hyper spectrum that contains hundred-to-thousand spectra, rather than a single spectrum. Second challenge is the complexity of Raman hyperspectral matrix with dataset size at megabyte (MB) or even bigger, which can be adopted using different algorithms ranging from image merging to multivariate analysis of chemometrics. Third challenge is the laser size that hinders the visualisation of small nanoplastics due to the laser diffraction (λ/2NA, ∼300 nm), which can be solved with involving the use of super-resolution. Signal processing, such as colour off-setting, Gaussian fitting (via deconvolution), and re-focus or image re-construction, are reviewed herein, which show a great promise for breaking through the diffraction limit.

SIGNIFICANCE

Overall, current studies along with further validation are imperative to refine these approaches and enhance the reliability, not only for nanoplastics research but also for broader investigations in the realm of nanomaterials.

Metabolic equilibrium and reproductive resilience: Freshwater gastropods under nanoplastics exposure

Nanoplastics (NPs) have gained increasing attention due to their widespread presence in aquatic environments and potential adverse effects on organisms. The interaction between NPs and freshwater gastropods can lead to a range of physiological and reproductive disturbances. In this study, we investigated the adverse effects of NPs (two size: 20 nm and 100 nm; three concentrations: 0.5, 50 and 100 ppm) on energy metabolism and reproductive fitness in freshwater gastropods Lymnean stagnalis after 21 days exposure. Briefly, the condition index negatively correlated with increasing NPs concentrations for both sizes. Bioaccumulation revealed a concentration-dependent trend in the 100 nm group, and the highest accumulation appeared in the 100 ppm group, compared to all the rest groups. This phenomenon could be attributed to the larger surface area which facilitates stronger attachment to tissues, while smaller particles could be cleared more readily from body. Carbohydrate and protein reserves remained largely unaffected at all concentrations. However, 100 nm NPs triggered stress responses, increasing lipid production, and 20 nm NPs potentially interfered with mitochondrial function, affecting electron transport system activity. Despite the variations observed in lipid levels and energy cost, the ratio of available energy to energy cost remained stable across for both NPs sizes, and this resilience suggests that cellular energy allocation endured undisturbed, hinting at mechanisms that enable gastropods to maintain their metabolic equilibrium. Reproductively, NPL-exposed groups had fewer clutches, with clutches per collection time decreasing over time for both sizes. In terms of egg development, shell growth and hatching rates remained unaffected, suggesting resilience in aquatic ecosystems.In conclusion, this study underscores the substantial impact of NPs on freshwater gastropods, raising ecological and reproductive concerns. The intricate interplay between nanoparticle size, concentration, and physiological responses highlights the complexity of NPs interactions in aquatic ecosystems, necessitating further research and regulatory measures.

A review on the fate of micro and nano plastics (MNPs) and their implication in regulating nutrient cycling in constructed wetland systems

This review discusses the micro-nano plastics (MNPs) and their interaction with physical, chemical and biological processes in a constructed wetland (CW) system that is typically used as a nature-based tertiary wastewater treatment for municipal as well as industrial applications. Individual components of the CW system such as substrate, microorganisms and plants were considered to assess how MNPs influence the CW processes. One of the main functions of a CW system is removal of nutrients like nitrogen (N) and phosphorus (P) and here we highlight the pathways through which the MNPs influence CW's efficacy of nutrient removal. The presence of morphologically (size and shape) and chemically different MNPs influence the growth rate of microorganisms important in N and P cycling, invertebrates, decomposers, and the plants which affect the overall efficiency of a CW treatment system. Certain plant species take up the MNPs, and some toxicity has been observed. This review focuses on two significant aspects: (1) the presence of MNPs in a significant concentration affects the efficiency of N and P removal, and (2) the removal of MNPs. Because MNPs reduce the enzyme activities in abundance and overproduction of ROS oxidizes the enzyme active sites, resulting in the depletion of proteins, ultimately inhibiting nitrogen and phosphorus removal within the substrate layer. The review found that the majority of the studies used sand-activated carbon (SAC), granular-activated carbon (GAC), rice straw, granular limestone, and calcium carbonate, as a substrate for CW treatment systems. Common plant species used in the CW include Phragmites, Arabidopsis thaliana, Lepidium sativum, Thalia dealbata, and Canna indica, which were also found to be dominant in the uptake of the MNPs in the CWs. The MNPs were found to affect earthworms such as Eisenia fetida, Caenorhabditis elegans, and, Enchytraeus crypticus, whereas Metaphire vulgaris were found unaffected. Though various mechanisms take place during the removal process, adsorption and uptake mechanism effectively emphasize the removal of MNPs and nitrogen and phosphorus in CW. The MNPs characteristics (type, size, and concentration) play a crucial role in the removal efficiency of nano-plastics (NPs) and micro-plastics (MPs). The enhanced removal efficiency of NPs compared to MPs can be attributed to their smaller size, resulting in a faster reaction rate. However, NPs dose variation showed fluctuating removal efficiency, whereas MPs dose increment reduces removal efficiency. MP and NPs dose variation also affected toxicity to plants and earthworms as observed from data. Understanding the fate and removal of microplastics in wetland systems will help determine the reuse potential of wastewater and restrict the release of microplastics. This study provides information on various aspects and highlights future gaps and needs for MNP fate study in CW systems.

Characterization of Nanoprecipitated PET Nanoplastics by 1H NMR and Impact of Residual Ionic Surfactant on Viability of Human Primary Mononuclear Cells and Hemolysis of Erythrocytes

Manufactured nanoplastic particles (NPs) are indispensable for in vitro and in vivo testing and a health risk assessment of this emerging environmental contaminant is needed. The high surface area and inherent hydrophobicity of plastic materials makes the production of NPs devoid of any contaminants very challenging. In this study, we produced nanoprecipitated polyethylene terephthalate (PET) NPs (300 nm hydrodynamic diameter) with an overall yield of 0.76%. The presence of the ionic surfactant sodium dodecyl sulfate (SDS) was characterized by 1H NMR, where the relative ratio of NP/surfactant was monitored on the basis of the chemical shifts characteristic of PET and SDS. For a wide range of surfactant/NP ratios (17:100 to 1.2:100), the measured zeta potential changed from -42.10 to -34.93 mV, but with an NP concentration up to 100 μg/mL, no clear differences were observed in the cellular assays performed in protein-rich media on primary human cells. The remaining impurities contributed to the outcome of the biological assays applied in protein-free buffers, such as human red blood cell hemolysis. The presence of SDS increased the NP-induced hemolysis by 1.5% in protein-rich buffer and by 7.5% in protein-free buffer. As the size, shape, zeta potential, and contaminants of NPs may all be relevant parameters for the biological effects of NPs, the relative quantification of impurities exemplified in our work by the application of 1H NMR for PET NPs and the ionic surfactant SDS could be a valuable auxiliary method in the quality control of manufactured NPs.

Visual mapping of global nanoplastics research progresses and hotspots: a scientometric assessment analysis

Environmental plastic wastes are continuously degraded into microplastics (MPs) and nanoplastics (NPs); the latter are more potentially harmful to organisms and human health as their smaller size and higher surface-to-volume ratio. Previous reviews on NPs mainly concentrate on specific aspects, such as sources, environmental behavior, and toxicological effects, but few focused on NPs-related scientific publications from a global point of view. Therefore, this bibliometric study aims to summarize the research themes and trends on NPs and also propose potential directions for future inquiry. Related papers were downloaded from the Web of Science Core Collection database on NPs published from 2008 to 2021, and then retrieved information was analyzed using CiteSpace 6.1 R2 and VOSviewer (version 1.6.). Research on NPs mainly involved environmental behaviors, toxicological effects, identification and extraction of NPs, whereas aquatic environments, especially marine systems, attracted more attentions from these scientists compare to terrestrial environments. Furthermore, the adsorption behavior of pollutants by NPs and the toxicological effects of organisms exposed to NPs are the present hotspots, while the regulation of humic acid (HA) on NPs behaviors and the environmental behavior of NPs in freshwater, like rivers and lakes, are the frontier areas of research. This study also explored the possible opportunities and challenges that may be faced in NPs research, which provide a valuable summary and outlook for ongoing NPs-related research, which may be of intrigue and noteworthiness for relevant researchers.

Insights into Anthropogenic Micro- and Nanoplastic Accumulation in Drinking Water Sources and Their Potential Effects on Human Health

Anthropogenic microplastics (MPs) and nanoplastics (NPs) are ubiquitous pollutants found in aquatic, food, soil and air environments. Recently, drinking water for human consumption has been considered a significant pathway for ingestion of such plastic pollutants. Most of the analytical methods developed for detection and identification of MPs have been established for particles with sizes > 10 μm, but new analytical approaches are required to identify NPs below 1 μm. This review aims to evaluate the most recent information on the release of MPs and NPs in water sources intended for human consumption, specifically tap water and commercial bottled water. The potential effects on human health of dermal exposure, inhalation, and ingestion of these particles were examined. Emerging technologies used to remove MPs and/or NPs from drinking water sources and their advantages and limitations were also assessed. The main findings showed that the MPs with sizes > 10 μm were completely removed from drinking water treatment plants (DWTPs). The smallest NP identified using pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS) had a diameter of 58 nm. Contamination with MPs/NPs can occur during the distribution of tap water to consumers, as well as when opening and closing screw caps of bottled water or when using recycled plastic or glass bottles for drinking water. In conclusion, this comprehensive study emphasizes the importance of a unified approach to detect MPs and NPs in drinking water, as well as raising the awareness of regulators, policymakers and the public about the impact of these pollutants, which pose a human health risk.

Micro(nano)plastics in the atmosphere of the Atlantic Ocean

The occurrence, long-range atmospheric transport and deposition of micro and nano plastics (MNPLs) remains un-quantified for the oceanic atmosphereopen ocean. Here we show the characterisation of MNPLs and the aerosol composition (PM₁₀) in a north-south Atlantic transect from Vigo (Spain) to Punta Arenas (Chile). The analytical procedure to assess the composition of MNPLs consisted of a double suspect screening approach of the polymers and additives, the two constituents of plastics. Polymers were analysed by size exclusion chromatography coupled with high-resolution mass spectrometry using an atmospheric pressure photoionization source operated in positive and negative conditions (HPLC(SEC)-APPI(+/-)-HRMS). Plastic additives were screened with high-performance liquid chromatography coupled to high-resolution mass spectrometry using an electrospray ionisation source (HPLC-ESI(+/-)-HRMS). The most common polymers were polyethylene (PE), polypropylene (PP), polyisoprene (PI), and polystyrene (PS), with the highest polymer concentration being 51.7 ng·m^-3 of PI. The air mass back trajectories showed the variable influence of oceanic and terrestrial air masses. These differences were reflected in the aerosol composition with different contributions of Saharan dust, sea spray aerosol, organic/elemental carbon, and MNPLs. Results showed that samples largely influenced by sea-spray and air masses originating from coastal South America and the north Atlantic subtropical gyre were more contaminated by MNPLs. Moreover, this information was complemented by the characterisation of the largest particles using scanning electron microscopy (SEM) and µ-Fourier Transform Infrared Spectroscopy (µ-FTIR). This work provides the first field evidence of the long-range transport of MNPLs in most of the Atlantic Ocean, as the result of dynamic coupling between the lower atmosphere and the surface ocean. Sea-spray formation arises as a key driver for the aerosolisation of MNPLs, and atmospheric transport followed by dry deposition may modulate the occurrence of MNPLs in large oceanic regions, issues that will require future research efforts.

Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics

Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D_h = 180.5 ± 5.8  nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of ζ = -43 ± 2 mV.

Removal efficiency and adsorption mechanisms of CeO2 nanoparticles onto granular activated carbon used in drinking water treatment plants

The presence of NPs in drinking water resources raises a global concern on their potential risk for human health, and whether or not drinking water treatment plants are able to effectively remove NPs to prevent their ingestion by humans. In this study, we investigate the efficiency of granular activated carbon (GAC), commonly used in conventional municipal water treatment processes, for the removal of CeO₂ NPs. In ultrapure water, NPs are found to have a good affinity for GAC and results indicate an increase in the adsorption capacity from 0.62 ± 0.10 to 5.05 ± 0.51 mg/g, and removal efficiency from 35 % ± 4 to 54 % ± 5 with increasing NPs concentration. Kinetic studies reveal that intraparticle diffusion is not the only rate controlling step indicating that mass transfer effect is also playing a role. Adsorption mechanisms are mainly controlled by the electrostatic attractions between the positively charged NPs and negatively charged GAC. Although electrostatic conditions in Lake Geneva water are less favorable for NPs adsorption, the adsorption capacity and removal efficiency are higher than in ultrapure water with values raising from 0.41 ± 0.17 to 7.13 ± 1.13 mg/g and 26 % ± 8 to 75 % ± 11, respectively. Furthermore, the external mass transfer process onto GAC surface is more important than for ultrapure water. NPs adsorption mechanism is explained by the presence of divalent cations and natural organic matter (NOM) which promote the formation of CeO₂ NPs-NOM-divalent cation heteroaggregates increasing both adsorption and removal efficiency by cation bridging.

Nanoplastics in the soil environment: Analytical methods, occurrence, fate and ecological implications

Soils play a very important role in ecosystems sustainability, either natural or agricultural ones, serving as an essential support for living organisms of different kinds. However, in the current context of extremely high plastic pollution, soils are highly threatened. Plastics can change the chemical and physical properties of the soils and may also affect the biota. Of particular importance is the fact that plastics can be fragmented into microplastics and, to a final extent into nanoplastics. Due to their extremely low size and high surface area, nanoplastics may even have a higher impact in soil ecosystems. Their transport through the edaphic environment is regulated by the physicochemical properties of the soil and plastic particles themselves, anthropic activities and biota interactions. Their degradation in soils is associated with a series of mechanical, photo-, thermo-, and bio-mediated transformations eventually conducive to their mineralisation. Their tiny size is precisely the main setback when it comes to sampling soils and subsequent processes for their identification and quantification, albeit pyrolysis coupled with gas chromatography-mass spectrometry and other spectroscopic techniques have proven to be useful for their analysis. Another issue as a consequence of their minuscule size lies in their uptake by plants roots and their ingestion by soil dwelling fauna, producing morphological deformations, damage to organs and physiological malfunctions, as well as the risks associated to their entrance in the food chain, although current conclusions are not always consistent and show the same pattern of effects. Thus, given the omnipresence and seriousness of the plastic menace, this review article pretends to provide a general overview of the most recent data available regarding nanoplastics determination, occurrence, fate and effects in soils, with special emphasis on their ecological implications.

Acute toxicity of nanoplastics on Daphnia and Gammarus neonates: Effects of surface charge, heteroaggregation, and water properties

Despite progress in evaluation of risk assessment, knowledge gaps largely exist understanding the toxicity of nanoplastics in aquatic systems considering nanoplastics surface properties, environmental media characteristics and species ecological traits. In this study, amidine - functionalized polystyrene nanoparticles (PS-NPLs) of 20, 40, 60 and 100 nm are considered using Geneva lake water and mineral water to investigate the behavior and effects in neonate organisms of the plankton Daphnia magna and the benthos Gammarus fossarum. Key parameters including ζ-potential, z-average diameter, conductivity, polydispersity index, pH, EC50 were investigated. The results showed that the toxicity of PS-NPLs exhibited a dose-response relationship, size- and exposure condition-dependent trend. The smaller size PS-NPLs (20 and 40 nm) induced higher adverse effects than PS-NPLs of 60 and 100 nm in both water conditions and crustacean species. Moreover, PS-NPLs were found more toxic in the mineral water compared to lake water. Principal component analysis evidenced that the surface charge and aggregation behavior are the most influential toxicity of PS-NPLs factor for D. magna and Gammarus fossarum, respectively. These results highlight the relationship between PS-NPLs intrinsic properties, their transformation behavior, water properties and species-specificity in the evaluation of PS-NPLs biological effects on crustacean neonates in natural aquatic environments.

Exploring the effect on the environment of encapsulated micro- and nano-plastics into asphalt mastics for road pavement

A new environmental problem is represented by the huge transformation of plastic waste released into the environment into small fragments, the so called micro- and nano-plastics, due to atmospheric phenomena. The smaller the size of the plastic fragments, the more their spreading into environmental compartments. The aim of this study is to test encapsulation into asphalt mastics of waste plastic material (WPM) as sustainable strategy to obtain road flexible pavements and to evaluate the potential release in water of micro and nano plastics. A new mastic mixing method was developed to blend the WPM with the bitumen contained into a bitumen emulsion (BE60/40) by adopting low mixing temperatures. Three different WPM contents, equal to 5, 10 and 20% by the weight of the bitumen contained in the BE60/40, were adopted to produce the mastics; the mastics' rheological properties, obtained by frequency sweep and multiple stress creep and recovery tests, were compared to those of a traditional asphalt mastic containing limestone filler. The aging of asphalt mastics was analyzed by soaking them in water and gradually lowering and raising temperature between -10 and 60 °C at predefined intervals. The addition of WPM improved greatly the asphalt mastic performance; in particular, for a WPM content of 10%, the rheological response in terms of stiffness remained unchanged after the mastic underwent thermal excursions in water. Encapsulation of micro and nano plastics into mastics reduced of more than 99% their potential water release.

Facile nanoplastics formation from macro and microplastics in aqueous media

The immense production of plastic polymers combined with their discordancy with nature has led to vast plastic waste contamination across the geosphere, from the oceans to freshwater reservoirs, wetlands, remote snowpacks, sediments, air and multiple other environments. These environmental pollutants include microplastics (MP), typically defined as small and fragmented plastics less than 5 mm in size, and nanoplastics (NP), particles smaller than a micrometer. The formation of micro and nanoplastics in aqueous media to date has been largely attributed to fragmentation of plastics by natural (i.e., abrasion, photolysis, biotic) or industrial processes. We present a novel method to create small microplastics (≲ 5 μm) and nanoplastics in water from a wide variety of plastic materials using a small volume of a solubilizer liquid, such as n-dodecane, in combination with vigorous mixing. When the suspensions or solutions are subjected to ultrasonic mixing, the particle sizes decrease. Small micro- and nanoparticles were made from commercial, real world and waste (aged) polyethylene, polystyrene, polycarbonate and polyethylene terephthalate, in addition to other plastic materials and were analyzed using dark field microscopy, Raman spectroscopy and particle size measurements. The presented method provides a new and simple way to create specific size distributions of micro- and nanoparticles, which will enable expanded research on these plastic particles in water, especially those made from real world and aged plastics. The ease of NP and small MP formation upon initial mixing simulates real world environments, thereby providing further insight into the behavior of plastics in natural settings.

Aging of colloidal contaminants and pathogens in the soil environment: Implications for nanoplastic and COVID-19 risk mitigation

Colloidal contaminants and pathogens are widely distributed in soil, whose tiny sizes and distinct surface properties render unique environmental behaviours. Because of aging, colloids can undergo dramatic changes in their physicochemical properties once in the soil environment, thus leading to diverse or even unpredictable environmental behaviour and fate. Herein, we provide a state-of-art review of colloid aging mechanisms and characteristics and implications for risk mitigation. First, we review aging-induced formation of colloidal contaminants and aging-associated changes. We place a special focus on emerging nanoplastic (NP) contaminants and associated physical, chemical, and biological aging processes in soil environments. Second, we assess aging and survival features of colloidal pathogens, especially viruses. Viruses in soils may survive from several days to months, or even several years in groundwater, depending on their rates of inactivation and the reversibility of attachment. Furthermore, we identify implications for risk mitigation based on aging mechanisms. Hotspots of (photo)chemical aging of NPs, including plastic gauzes at construction sites and randomly discarded plastic waste in rural areas, are identified as area requiring greater research attention. For COVID-19, we suggest taking greater care in regions where viruses are persist for long periods, such as cold climate regions. Soil amendment with quicklime (CaO) may act as an effective means for pathogen disinfection. Future risk mitigation of colloidal contaminants and pathogens relies on a better understanding of aging mechanisms and more sophisticated models accurately depicting processes in real soil environments.

Behavioural, physiological and molecular responses of the Antarctic fairy shrimp Branchinecta gaini (Daday, 1910) to polystyrene nanoplastics

Plastic pollution represents an emerging environmental issue in terrestrial Antarctica, especially in the Antarctic Peninsula and Maritime Antarctica, which have been recently recognized as hot spots for plastic litter. In these regions, freshwater (FW) environments such as lakes host isolated ecosystems and species that can be severely affected by increasing environmental and anthropogenic stressors, which include plastics that are still overlooked. In this study, we investigated for the first time the impact of nanoplastics on adults of the fairy shrimp Branchinecta gaini (Order Anostraca) populating Antarctic FW ecosystems, using surface charged polystyrene nanoparticles (PS NPs) as a proxy. Short-term acute toxicity (48 h) was investigated by exposing adults to carboxyl (-COOH, 60 nm) and amino-modified (-NH₂, 50 nm) PS NPs at 1 and 5 μg mL^-1. Biodisposition of PS NPs and lethal and sub-lethal effects (i.e., swimming, moulting, histology, gene expression) were assessed. Behaviour of PS NPs in Antarctic FW media was monitored through 48 h of exposure showing that both PS NPs kept their nanoscale size in the Antarctic FW media. Survival of fairy shrimp adults over short-term exposure was not affected, on the other hand an increase in moulting rate and alterations in the gut epithelium were observed upon exposure to both PS NPs. Significant alterations at the behavioural (ventilation rate) and molecular (up-regulation of Hsp70mit, Hsp83, Sod, P450) levels were related to PS NP surface charge and associated with PS-NH₂ exposure only. Nanoplastics could represent a threat for Antarctic FW biodiversity and the Antarctic fairy shrimp could be a valuable model for assessing their impact on such remote and pristine aquatic ecosystems.

The interaction of micro/nano plastics and the environment: Effects of ecological corona on the toxicity to aquatic organisms

Concerns about the micro/nano plastics (MNPs) exposure risks have risen in recent years. The ecological corona (EC), which is generated by the interaction between MNPs and environmental substances, has a significant impact on their environmental fate and ecological risks. As the largest sink of MNPs, the aquatic environment is of great significance for understanding the environmental behaviour of MNPs. Transmission Electron Microscope (TME), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscope (SEM), Dynamic Light Scattering (DLS) and other analytical methods have been used as effective methods to analyse the formation process of EC and detect the existing EC directly or indirectly on the surface of MNPs. The physicochemical properties of MNPs, complex aquatic environments and ageing time have been identified as the key factors affecting EC formation in aquatic environments. Moreover, the EC absorbed on MNPs significantly changed their environmental behaviour and toxicity to aquatic organisms. This review gives a full understanding of the EC formation progress on the surface of MNPs and different analytical methods for EC have been summarised which can further assist the ecological risk assessment of MNPs in the aquatic environment.

Plastic is in the air: Impact of micro-nanoplastics from airborne pollution on Tillandsia usneoides (L.) L. (Bromeliaceae) as a possible green sensor

Due to the increasing evidence of widespread plastic pollution in the air, the impact on plants of airborne particles of polycarbonate (PC), polyethyleneterephthalate (PET), polyethylene (PE), and polyvinylchloride (PVC) was tested by administering pristine and aged airborne micro-nanoplastics (MNPs) to Tillandsia usneoides for two weeks. Here we showed that exposure to pristine MNPs, significantly reduced plant growth with respect to controls. Particularly, PVC almost halved plant development at the end of the treatment, while the other plastics exerted negative effects on growth only at the beginning of the exposure, with final stages comparable to those of controls. Plants exposed to aged MNPs showed significantly decreased growth at early stages with PC, later in the growth with PE, and even later with PET. Aged PVC did not exert a toxic effect on plants. When present, the plastic-mediated reduction in plant growth was coupled with a decrease in photosynthetic activity and alterations in the plant concentration of macro- and micronutrients. The plastic particles were showed to adhere to the plant surface and, preferentially, on the trichome wings. Our results reported, for the first time, evidence of negative effects of airborne plastic pollution on plant health, thus raising concerns for related environmental risks.

Sensitivity of the Transport of Plastic Nanoparticles to Typical Phosphates Associated with Ionic Strength and Solution pH

The influence of phosphates on the transport of plastic particles in porous media is environmentally relevant due to their ubiquitous coexistence in the subsurface environment. This study investigated the transport of plastic nanoparticles (PNPs) via column experiments, paired with Derjaguin–Landau–Verwey–Overbeek calculations and numerical simulations. The trends of PNP transport vary with increasing concentrations of NaH₂PO₄ and Na₂HPO₄ due to the coupled effects of increased electrostatic repulsion, the competition for retention sites, and the compression of the double layer. Higher pH tends to increase PNP transport due to the enhanced deprotonation of surfaces. The release of retained PNPs under reduced IS and increased pH is limited because most of the PNPs were irreversibly captured in deep primary minima. The presence of physicochemical heterogeneities on solid surfaces can reduce PNP transport and increase the sensitivity of the transport to IS. Furthermore, variations in the hydrogen bonding when the two phosphates act as proton donors will result in different influences on PNP transport at the same IS. This study highlights the sensitivity of PNP transport to phosphates associated with the solution chemistries (e.g., IS and pH) and is helpful for better understanding the fate of PNPs and other colloidal contaminants in the subsurface environment.

Ageing and fragmentation of marine microplastics

The generation of small fragments from the environmental ageing of microplastics (MPs) is still a poorly known process. This work addresses the fragmentation of MPs obtained from marine debris consisting of polyethylene and polypropylene (PE and PP in environmental mixture) and polystyrene (PS) after exposure to accelerated ageing by irradiation and mechanical stirring. Number particle size distribution in the 1-100 μm range was assessed by combining laser diffractometry with particle counts from flow cytometry. The results showed the generation of a high number of small MP particles, which reached 10⁵-10⁶ items/mg of plastic with most fragments <2 μm. The results showed that environmentally aged MPs give rise to a larger number of small MPs in a pattern consistent with progressive fragmentation in the three spatial dimensions. The proportion of small MPs was much higher than that found in current sampling campaigns, suggesting a severe underestimation of the environmental presence of small MPs. We also demonstrated the generation of nanoplastics (NPs) in the fraction <1 μm from irradiated runs. The results showed that the mechanism that produced nanoplastics (NPs) from MPs was irradiation, which yielded up to 10¹¹-10¹³ NPs/g with particle size in the few hundreds of nm range. Our results are relevant for the assessment of fate and risk of plastic debris in the environment showing that the number of small plastic fragments produced during the ageing of MPs is much larger than expect from the extrapolation of larger size populations.

Evaluating the Occurrence of Polystyrene Nanoparticles in Environmental Waters by Agglomeration with Alkylated Ferroferric Oxide Followed by Micropore Membrane Filtration Collection and Py-GC/MS Analysis

Although nanoplastics (NPs) are recognized as emerging anthropogenic particulate pollutants, the occurrence of NPs in the environment is rarely reported, partly due to the lack of sensitive methods for the concentration and detection of NPs. Herein, we present an efficient method for enriching NPs of different compositions and various sizes. Alkylated ferroferric oxide (Fe₃O₄) particles were prepared as adsorbents for highly efficient capture of NPs in environmental waters, and the formed large Fe₃O₄-NP agglomerates were separated by membrane filtration. Detection limits of 0.02-0.03 μg/L were obtained for polystyrene (PS) and poly(methyl methacrylate) (PMMA) NPs by detection with pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). When analyzing real water samples from different sources, it is remarkable that PS NPs were detected in 11 out of 15 samples with concentrations ranging from <0.07 to 0.73 μg/L, while PMMA were not detected. The wide detection of PS NPs in our study confirms the previous speculation that NPs may be ubiquitous in the environmental waters. The accurate quantification of PS NPs in environmental waters make it possible to monitor the pollution status of NPs in aquatic systems and evaluate their potential risks.

In Vitro High-Throughput Toxicological Assessment of Nanoplastics

Sub-micrometer particles derived from the fragmentation of plastics in the environment can enter the food chain and reach humans, posing significant health risks. To date, there is a lack of adequate toxicological assessment of the effects of nanoplastics (NPs) in mammalian systems, particularly in humans. In this work, we evaluated the potential toxic effects of three different NPs in vitro: two NPs obtained by laser ablation (polycarbonate (PC) and polyethylene terephthalate (PET1)) and one (PET2) produced by nanoprecipitation. The physicochemical characterization of the NPs showed a smaller size, a larger size distribution, and a higher degree of surface oxidation for the particles produced by laser ablation. Toxicological evaluation performed on human cell line models (HePG2 and Caco-2) showed a higher toxic effect for the particles synthesized by laser ablation, with PC more toxic than PET. Interestingly, on differentiated Caco-2 cells, a conventional intestinal barrier model, none of the NPs produced toxic effects. This work wants to contribute to increase knowledge on the potential risks posed by NPs.

Nanoplastics: Status and Knowledge Gaps in the Finalization of Environmental Risk Assessments

Nanoplastics (NPs) are particles ranging in size between 1 and 1000 nm, and they are a form of environmental contaminant of great ecotoxicological concern. Although NPs are widespread across ecosystems, they have only recently garnered growing attention from both the scientific community and regulatory bodies. The present study reviews scientific literature related to the exposure and effects of NPs and identifies research gaps that impede the finalization of related environmental risk assessments (ERAs). Approximately 80 articles published between 2012 and 2021 were considered. Very few studies (eight articles) focused on the presence of NPs in biotic matrices, whereas the majority of the studies (62 articles) assessed the lethal and sublethal effects of NPs on aquatic and terrestrial organisms. Whilst many studies focused on nude NPs, only a few considered their association with different aggregates. Amongst NPs, the effects of polystyrene are the most extensively reported to date. Moreover, the effects of NPs on aquatic organisms are better characterized than those on terrestrial organisms. NP concentrations detected in water were close to or even higher than the sublethal levels for organisms. An ERA framework specifically tailored to NPs is proposed.

Autofluorescence of Model Polyethylene Terephthalate Nanoplastics for Cell Interaction Studies

This work contributes to fill one of the gaps regarding nanoplastic interactions with biological systems by producing polyethylene terephthalate (PET) model nanoplastics, similar to those found in the marine environment, by means of a fast top-down approach based on mechanical fragmentation. Their size distribution and morphology were characterized by laser diffraction and atomic force microscopy (AFM). Their autofluorescence was studied by spectrofluorimetry and fluorescence imaging, being a key property for the evaluation of their interaction with biota. The emission spectra of label-free nanoplastics were comparable with those of PET nanoplastics labeled with Nile red. Finally, the suitability of label-free nanoplastics for biological studies was assessed by in vitro exposure with Mytilus galloprovincialis hemolymphatic cells in a time interval up to 6 h. The nanoplastic internalization into these cells, known to be provided with phagocytic activity, was assessed by fluorescence microscopy. The obtained results underlined that the autofluorescence of the model PET nanoplastics produced in the laboratory was adequate for biological studies having the potential to overcome the disadvantages commonly associated with several fluorescent dyes, such as the tendency to also stain other organic materials different from plastics, to form aggregates due to intermolecular interactions at high concentrations with a consequent decrease in fluorescence intensity, and to dye desorption from nanoparticles. The results of the autofluorescence study provide an innovative approach for plastic risk assessment.

Nanoplastic Labelling with Metal Probes: Analytical Strategies for Their Sensitive Detection and Quantification by ICP Mass Spectrometry

The detection and quantification of nanoplastics in aquatic environments is one of the major challenges in environmental and analytical research nowadays. The use of common analytical techniques for this purpose is not only hampered by the size of nanoplastics, but also because they are mainly made of carbon. In addition, the expected concentrations in environmental samples are below the detection limit of the majority of analytical techniques. In this context, the great detection capabilities of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in its Single Particle mode (SP-ICP-MS) have made of this technique a good candidate for the analysis of nanoplastics. Since the monitoring of carbon by ICP-MS faces several difficulties, the use of metal tags, taking advantage of the great potential of nanoplastics to adsorb chemical compounds, has been proposed as an alternative. In this perspectives paper, three different strategies for the analysis of polystyrene (PS) nanoplastics by SP-ICP-MS based on the use of metals species (ions, hydrophobic organometallic compound, and nanoparticles) as tags are presented and discussed. Advantages and disadvantages of each strategy, which rely on the labelling process, are highlighted. The metal nanoparticles labelling strategy is shown as a promising tool for the detection and quantification of nanoplastics in aqueous matrices by SP-ICP-MS.