Previous studies of uptake and effects of nanoplastics by marine organisms have been conducted at what may be unrealistically high concentrations. This is a consequence of the analytical challenges in tracking plastic particles in organisms at environmentally relevant concentrations and highlights the need for new approaches. Here, we present pulse exposures of 14C-radiolabeled nanopolystyrene to a commercially important mollusk, Pecten maximus, at what have been predicted to be environmentally relevant concentrations (<15 μg L–1). Uptake was rapid and was greater for 24 nm than for 250 nm particles. After 6 h, autoradiography showed accumulation of 250 nm nanoplastics in the intestine, while 24 nm particles were dispersed throughout the whole-body, possibly indicating some translocation across epithelial membranes. However, depuration was also relatively rapid for both sizes; 24 nm particles were no longer detectable after 14 days, although some 250 nm particles were still detectable after 48 days. Particle size thus apparently influenced the biokinetics and suggests a need for chronic exposure studies. Modeling extrapolations indicated that it could take 300 days of continued environmental exposure for uptake to reach equilibrium in scallop body tissues although the concentrations would still below 2.7 mg g–1. Comparison with previous work in which scallops were exposed to nonplastic (silver) nanomaterials of similar size (20 nm), suggests that nanoparticle composition may also influence the uptake tissue distributions somewhat.

Owing to their physical and chemical properties, particles generated by the abrasion of tyre tread against road surfaces, or tyre wear particles, are recognised as microplastics. Recent desk-based studies suggest tyre wear to be a major contributor of microplastic emissions to the environment. This study aimed to quantify tyre wear in roadside drains and the natural environment near to a major road intersection. Tyre particles were identified by visual identification and a subsample confirmed as tyre wear by GC-MS using Ncyclohexyl-2-benzothiazolamine (NCBA) as a marker. The abundance of tyre wear within roadside drains was greater in areas associated with increased braking and accelerating than high traffic densities (p = <0.05). Tyre particle abundance in the natural environment ranged from 0.6±0.33 to 65±7.36 in 5 mL of material, with some evidence of decline with distance from the road. This study offers preliminary data regarding the generation and abundance of this under-researched microplastic.

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International audienceSoils in riparian wetlands are periodically flooded, resulting in the establishment of reducing conditions and the solubilization of As, subsequently to the reductive dissolution of Fe(III)-oxyhydroxides. When the water level decreases, the wetlands are reoxidized. However, although the behavior of As under the reducing period is well documented, there is a lack of information regarding its behavior during the oxidizing period.In this study, we investigated As speciation in oxidation products from an initially reduced wetland soil solution recovered from the Naizin-Kervidy riparian wetland (France). The oxidation products were studied using NanoSIMS analysis and synchrotron X-ray techniques. These products were enriched in organic carbon, Fe and As compared with the soil and soil solution. The NanoSIMS analysis showed a colocalization of As and Fe but also revealed the presence of As hotspots where As was either associated with Fe or organic matter (OM). X-ray absorption spectroscopy (XAS) showed that As was sorbed to Fe(III)-oxyhydroxides. The linear combination fitting (LCF) of the As K-edge XANES revealed that As was not totally oxidized (i.e. between 65 and 100% of As(V)). Shell-by-shell fits of the As K-edge EXAFS showed that As formed binuclear edge-sharing 2E (RAs-Fe = 2.74–2.95 Å) and corner-sharing 2C (RAs-Fe = 3.28–3.43 Å) complexes with Fe.In addition to study of natural samples, oxidized reference samples were analyzed and demonstrated the role of OM on As speciation. The persistence of As(III) was explained by OM control on the As carrying phase during the oxidation, via the formation of nano-lepidocrocite and small Fe-clusters bound to OM. The small size of the Fe phase led to an increased capacity for As adsorption and an increase in 2E sites compared to 2C active sites for As(III) oxidation

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Search for low-energy b contaminations in industrial environments requires using Liquid Scintillation Counting. This indirect measurement method supposes a fine control from sampling to measurement itself. Thus, in this paper, we focus on the definition of a measurement method, as generic as possible, for both smears and aqueous samples' characterization. That includes choice of consumables, sampling methods, optimization of counting parameters and definition of energy windows, using the maximization of a Figure of Merit. Detection limits are then calculated considering these optimized parameters. For this purpose, we used PerkinElmer Tri-Carb counters. Nevertheless, except those relative to some parameters specific to PerkinElmer, most of the results presented here can be extended to other counters.

While there is great demand for effective, affordable radiation detectors in various applications, many commonly used scintillators have major drawbacks. Conventional inorganic scintillators have a fixed emission wavelength and require expensive, high-temperature synthesis; plastic scintillators, while fast, inexpensive, and robust, have low atomic numbers, limiting their X-ray stopping power. Formamidinium lead halide perovskite nanocrystals show promise as scintillators due to their high X-ray attenuation coefficient and bright luminescence. Here, we used a room-temperature, solution-growth method to produce mixed-halide FAPbX3 (X = Cl, Br) nanocrystals with emission wavelengths that can be varied between 403 and 531 nm via adjustments to the halide ratio. The substitution of bromine for increasing amounts of chlorine resulted in violet emission with faster lifetimes, while larger proportions of bromine resulted in green emission with increased luminescence intensity. By loading FAPbBr3 nanocrystals into a PVT-based plastic scintillator matrix, we produced 1 mm-thick nanocomposite scintillators, which have brighter luminescence than the PVT-based plastic scintillator alone. While nanocomposites such as these are often opaque due to optical scattering from aggregates of the nanoparticles, we used a surface modification technique to improve transmission through the composites. A composite of FAPbBr3 nanocrystals encapsulated in inert PMMA produced even stronger luminescence, with intensity 3.8× greater than a comparative FAPbBr3/plastic scintillator composite. However, the luminescence decay time of the FAPbBr3/PMMA composite was more than 3× slower than that of the FAPbBr3/plastic scintillator composite. We also demonstrate the potential of these lead halide perovskite nanocomposite scintillators for low-cost X-ray imaging applications.

Available analytical methods cannot detect nanoplastics at environmentally realistic concentrations in complex matrices such as biological tissues. Here, we describe a one-step polymerization method, allowing direct radiolabeling of a sulfonate end-capped nano-sized polystyrene (nPS; proposed as a model nanoplastic particle representing negatively charged nanoplastics). The method, which produces nanoplastics trackable in simulated environmental settings which have already been used to investigate the behavior of a nanoplastic in vivo in a bivalve mollusc, was developed, optimized and successfully applied to synthesis of 14C-labeled nPS of different sizes. In addition to a description of the method of synthesis, we describe the details for quantification, mass balance and recovery of the labelled particles from complex matrices offered by the radiolabelling approach. The radiolabeling approach described here, coupled to use of a highly sensitive autoradiographic method for monitoring nanoplastic body burden and distributions, may provide a valuable procedure for investigating the environmental pathways followed by negatively charged nanoplastics at low predicted environmental concentrations. Whether the behaviour of the synthetic nPS manufactured here, synthesised using a very common inititator, represents that of manufactured nPS found in the environment, remains to be seen.