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This work reports the production of nanoplastics (NPs) from polypropylene (PP) free of the antioxidant Irgafos® 168 (IRG) and alkane oligomers (ALK). PP pellets were milled into a powder with particle sizes in the 100–500 μm range. Additives and oligomers were removed using dichloromethane, and the powder exposed to UV irradiation, followed by filtration through 1 μm filters. PP suspensions, free of antioxidant and oligomers, were reloaded with IRG and ALK to their original commercial concentrations. This approach allowed testing the aquatic toxicity of IRG at concentrations compromised by water solubility limits. Toxicity assays using the cladoceran Daphnia magna with 24–48 h immobilization of neonates as endpoint showed toxicity for NPs containing IRG, with EC 20 (48 h) in the 1.8–3.5 mg/L range, that corresponded to IRG exposure <1.2 μg/L. Suspensions of PP containing ALK, but not IRG, exhibited low toxicity (EC 20 > 20 mg/L). The results allowed estimating the toxicity of IRG with a EC 50 value of 3.3 ± 1.1 μg/L. Assays with different proportions of IRG and its oxidized form showed no differences. This work demonstrated the aquatic toxicity of IRG, for which there were no previous data, and developed a method for testing the toxicity of non-polar additives without being limited by their solubility. [Display omitted] • Additive-free polypropylene nanoplastics can be used as carrier for toxicity tests. • Additive-free polypropylene nanoplastics showed low toxicity to Daphnia magna. • The toxicity of nanoplastic suspensions reloaded with polypropylene oligomers was low. • Irgafos® 168 in reloaded nanoplastics was toxic, reaching EC20 (48 h) at <1.2 μg/L. [ABSTRACT FROM AUTHOR]

In this work, we studied the hydrolytic and photochemical degradation of three low-density polyethylene (LDPE) materials, within the size range of microplastics (MP). The MPs were exposed to mechanical agitation and UV irradiation equivalent to one year of solar UVB + UVA in a stirred photoreactor. Flow cytometry was used to track the formation of small (1–25 μm) MPs by applying Mie's theory to derive the size of MP particles from scattering intensity readings. The calculation was based on a calibration with polystyrene (PS) beads. The results showed that the generation of 1–5 μm MP reached 104-105 MPs in the 1–25 μm range per gram of LDPE. ATR-FTIR and micro-FTIR measurements evidenced the formation of oxygenated moieties, namely hydroxyl, carbonyl, and carbon-oxygen bonds, which increased with irradiation time. We also found evidence of the production of a high number of nanoplastics (<1 μm, NPs). The Dynamic Light Scattering size of secondary NPs was in the hundreds of nm range and might represent up to 1010 NPs per gram of LDPE. Our results allowed the unambiguous spectroscopic assessment of the generation of NPs from LDPE under conditions simulating environmental exposure to UV irradiation and used flow cytometry for the first-time to track the formation of secondary MPs. [Display omitted] • The mechanical fragmentation of LDPE produces high number of secondary MPs. • Solar photochemical ageing of LDPE produces NPs from secondary MPs. • Secondary MPs/NPs showed oxygenated moieties that increased upon irradiation. • High number of secondary MPs in the 1–25 μm range representing 104-105 items/g LDPE. • Estimation of the concentration of NPs in the order of 1010 NPs/g LDPE. [ABSTRACT FROM AUTHOR]

• Mesoporous UiO-66 and derivatives prepared by direct solvothermal synthesis. • Mesoporous UiO-66s were used as adsorbents to remove polystyrene nanospheres. • UiO-66-NH 2 /P123 showed high efficiency for nanoplastics removal. Nanoplastics have garnered significant global attention as emerging environmental contaminants due to their susceptibility to be internalized by organisms, potentially leading to higher ecological and health risks compared to microplastics. Recently, adsorption has emerged as a promising strategy for nanoplastic removal, and new adsorbents have demonstrated impressive performance in this regard. In this study, we focused on the removal of polystyrene nanoplastics (NPs) from aqueous environments using a series of mesoporous Metal Organic Frameworks (MOFs). We synthesized mesoporous UiO-66 and its derivatives (–OH and –NH 2) through direct solvothermal synthesis in the presence of cetyltrimethylammonium bromide (CTAB) or Pluronic-type triblock copolymer (P123). The resulting materials had high crystallinity and displayed a hierarchical mesoporosity. Remarkably, we found that UiO-66-NH 2 /P123 demonstrated exceptional efficiency in removing NPs, achieving up to 100 % removal efficiency at an initial concentration of 1 g·L-1. This indicates its potential as a highly effective adsorbent for nanoplastic removal from aqueous media. [ABSTRACT FROM AUTHOR]

• The main synthetic polymers detected were polyamide, polyester, and polypropylene. • Particle size and mass distributions parameterized by power law distributions. • The average concentration of microplastics was 12.5 ± 4.9 MPs/m3 or 50.3 ng/L. • Scale invariant fragmentation would yield very low concentration of nanoplastics. • Daily consumption of 1.5 L represents 6.8 MPs per year per person weighing 24.9 µg. The purpose of this study was to investigate the occurrence of microplastics (MPs) in drinking water in Spain by comparing tap water from different locations using common sampling and identification procedures. We sampled tap water from 24 points in 8 different locations from continental Spain and the Canary Islands by means of 25 μm opening size steel filters coupled to household connections. All particles were measured and spectroscopically characterized including not only MPs but also particles consisting of natural materials with evidence of industrial processing, such as dyed natural fibres, referred insofar as artificial particles (APs). The average concentration of MPs was 12.5 ± 4.9 MPs/m3 and that of anthropogenic particles 32.2 ± 12.5 APs/m3. The main synthetic polymers detected were polyamide, polyester, and polypropylene, with lower counts of other polymers including the biopolymer poly(lactic acid). Particle size and mass distributions were parameterized by means of power law distributions, which allowed performing estimations of the concentration of smaller particles provided the same scaling parameter of the power law applies. The calculated total mass concentration of the identified MPs was 45.5 ng/L. The observed size distribution of MPs allowed an estimation for the concentration of nanoplastics (< 1 µm) well below the ng/L range; higher concentrations are not consistent with scale invariant fractal fragmentation. Our findings showed that MPs in the drinking water sampled in this work do not represent a significant way of exposure to MPs and would probably pose a negligible risk for human health. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, we used palladium-doped polystyrene NPLs (PS-NPLs with a primary size of 286 ± 4 nm) with an irregular surface morphology which allowed for particle tracking and evaluation of their toxicity on two primary producers (cyanobacterium, Anabaena sp. PCC7120 and green algae, Chlamydomonas reinhardtii) and one primary consumer (crustacean, Daphnia magna). the concentration range for Anabaena and C. reinhardtii was from 0.01 to 1000 mg/L and for D. magna , the range was from 7.5 to 120 mg/L.EC 50 s ranged from 49 mg NPLs/L for D. magna (48hEC 50 s) to 248 mg NPLs/L (72hEC 50 s for C. reinhardtii). PS-NPLs induced dose-dependent reactive oxygen species overproduction, membrane damage and metabolic alterations. To shed light on the environmental fate of PS-NPLs, the short-term distribution of PS-NPLs under static (using lake water and sediments) and stirring (using river water and sediments) conditions was studied at laboratory scale. The results showed that most NPLs remained in the water column over the course of 48 h. The maximum percentage of settled particles (∼ 30 %) was found under stirring conditions in comparison with the ∼ 10 % observed under static ones. Natural organic matter increased the stability of the NPLs under colloidal state while organisms favored their settlement. This study expands the current knowledge of the biological effects and fate of NPLs in freshwater environments. [Display omitted] • Pd-doped polystyrene nanoplastics were only lethal at high concentrations. • EC 50 s ranged from 49 mg NPLs/L for D. magna to 248 mg NPLs/L for C. reinhardtii. • Pd-doped nanoplastics caused membrane damage by physical interaction. • After 48 h ∼ 50 % of the nanoplastics remained in water under colloidal stability. • The presence of organisms promoted nanoplastic settlement in the sediments. [ABSTRACT FROM AUTHOR]