Examining the Relevance of the Microplastic-Associated Additive Fraction in Environmental Compartments

Plastic contamination is ubiquitous in the environment and has been related to increasing global plastic usage since the 1950s. Considering the omnipresence of additives in plastics, the risk posed by this contamination is related not only to the physical effects of plastic particles but also to their additive content. Until now, most routine environmental monitoring programs involving additives have not considered the presence of these additives still associated with the plastic they were added to during their production. Understanding environmental additive speciation is essential to address the risk they pose through their bioavailability and plastic-associated transport. Here, we present and apply a theoretical framework for sampling and analytical procedures to characterize the speciation of hydrophobic nonionized additives in environmental compartments. We show that this simple framework can help develop sampling and sample treatment procedures to quantify plastic-associated additives and understand additive distribution between plastics and organic matter. When applied to concrete cases, internal consistency checks with the model allowed for identifying plastic-associated additives in a sample. In other cases, the plastic-organic carbon ratio and additive concentration in the matrix are key factors affecting the ability to identify plastic-associated additives. The effect of additive dissipation through diffusion out of plastic particles is also considered.publishedVersio

Molecular Impacts of Dietary Exposure to Nanoplastics Combined or Not with Arsenic in the Caribbean Mangrove Oysters (Isognomon alatus)

Nanoplastics (NPs) are anthropogenic contaminants that raise concern, as they cross biological barriers. Metals’ adsorption on NPs’ surface also carries ecotoxicological risks to aquatic organisms. This study focuses on the impacts of three distinct NPs on the Caribbean oyster Isognomon alatus through dietary exposure. As such, marine microalgae Tisochrysis lutea were exposed to environmentally weathered mixed NPs from Guadeloupe (NPG), crushed pristine polystyrene nanoparticles (PSC), and carboxylated polystyrene nanoparticles of latex (PSL). Oysters were fed with NP-T. lutea at 10 and 100 µg L−1, concentrations considered environmentally relevant, combined or not with 1 mg L−1 pentoxide arsenic (As) in water. We investigated key gene expression in I. alatus’ gills and visceral mass. NP treatments revealed significant induction of cat and sod1 in gills and gapdh and sod1 in visceral mass. As treatment significantly induced sod1 expression in gills, but once combined with any of the NPs at both concentrations, basal mRNA levels were observed. Similarly, PSL treatment at 100 µg L−1 that significantly induced cat expression in gills or sod1 in visceral mass showed repressed mRNA levels when combined with As (reduction of 2222% and 34%, respectively, compared to the control). This study suggested a protective effect of the interaction between NPs and As, possibly by decreasing both contaminants’ surface reactivity

Consecuencias económicas de la prohibición del Plástico en Colombia

Trabajo de InvestigaciónEl plástico es un material orgánico y que durante su fabricación son muchos los usos para obtener diferentes formas, además de su utilización económica para la industria y su bajo costo de fabricación, es inevitable no estar rodeados de artículos hechos a base de este componente. Sin embargo, el plástico se ha convertido en un problema que con el pasar de los días se va creciendo, dado que se encuentra en casi todos los productos que utilizamos a diario, ya sea en consumo personal o en las actividades y hasta en los alimentos. La producción y consumo de plásticos en el mundo durante los últimos años ha aumentado de forma acelerada, alcanzando cifras alarmantes y cuya consecuencia principal es la contaminación del entorno y el medio ambiente, poniendo en peligro las especies que habitan los ecosistemas del planeta, principalmente los océanos, mares y ríos; razón por la cual se es necesario empezar a revisar este tema y así tomar las diferentes decisiones que permitan dar una solución de fondo y así reducir el consumo, apoyándose en programas para la reutilización y el reciclaje de desechos impulsados por el Estado y la población en general.1. Capítulo 1: Introducción 2. Capítulo 2: Marco de Referencia 3. Resultados y Discusión de resultados 4. Conclusiones 5. ReferenciasPregradoEconomist

SOURCES ET DEVENIR DES NANOPARTICULES MANUFACTUREES ET ANTHROPIQUES : TRANSPORT, ACCUMULATION ET REACTIVITE AUX INTERFACES

Aqueous humor formation and intraocular pressure in mammals having ocular hypertension or glaucoma may be reduced by topically administering to a hypertensive eye an ophthalmologically acceptable amount of a dopamine antagonist or acid addition salt thereof. A preferred group of dopamine antagonists is the butyrophenones, especially haloperidol, trifluperidol, and moperone. An ophthalmic composition for topically treating glaucoma may comprise an aqueous solution containing 0.01% to 5% by weight of a water-soluble ophthalmologically acceptable acid addition salt of such dopamine antagonist.U

Selection of an appropriate aqueous nano-fullerene (nC60) preparation protocol for studying its environmental fate and behavior

International audienceThe inevitable future environmental release of fullerene nanoparticles (nC60) requires the development of specific analytical methodologies that are able to identify, characterize and quantify these new nanomaterial species. As is well detailed in the literature, the characterization of nanoscale materials requires the consideration of several physical and chemical parameters, such as size, size distribution, shape, charge surface, and surface chemistry. All of these parameters must be determined to assess the representative impact of manufactured nanoparticles in environmental media. Nevertheless, appropriate and environmentally representative nanoparticles standards are not currently available for the development of such analytical strategy and validating measurements. This tentative critical review presents a different pathway for the preparation of fullerene nanoparticles in aqueous media for environmental studies (characterization, fate and behavior determination). The principal drawbacks and bias measurement are presented as well as the consequences of this new pathway for our understanding of environmental implications

Improving the understanding of fullerene (nC60) aggregate structures: Fractal dimension characterization by static light scattering coupled to asymmetrical flow field flow fractionation

International audienceFullerene (C60) aggregation mechanisms in aqueous media require considerable attention in the near future due to the heavy use and application of fullerene-based products within the context of nanotechnology. Such intensive development will result in the release of massive amounts of C60 in aqueous environmental systems in the aggregate form (nC60). In that sense, the aggregation mechanisms need to be fully determined to better evaluate the environmental fate and behavior of C60. To fulfil these needs, the aim of this work was to extensively characterize the aggregation mechanisms of fullerene aggregates in aqueous media by asymmetrical flow field fractionation (AF4) coupled to static light scattering (SLS). We developed a sequential ultrafiltration method that allows the fractionation of the whole nC60 size distribution into different size classes (1–100–200–450–800 nm). Following a preliminary analysis by dynamic light scattering (DLS), we optimized several AF4 separation methods to allow screening of these colloidal size classes of nC60 with high efficiency and resolution. The fractal dimension (Df) of this entire size class was characterized directly on-line according to the radius of gyration through a combination of angle-dependent light scattering and fractal dimension analysis. We demonstrate the possible formation and persistence of colloidal populations of nC60 in aqueous media from a few nanometers up to 800 nm. Df values ranging from 1.2 to 2.8, based on the nC60 colloidal size range, strongly depend on the method of the sample filtration

Développement de méthodes de Fractionnement par couplage Flux-Force (FFF)-multi-détection pour la caractérisation de nanotubes de carbone dispersés en milieu aqueux.

Les nanotubes de carbone (CNT) de par leurs propriétés exceptionnelles sont devenus l objet d une recherche et d un développement intensifs, et des multinationales comme des industries de pointe en ont fait leur priorité en terme de production et d utilisation. Pour mieux maîriser et optimiser leurs propriétés et leurs applications, il est essentiel de les caractériser physico-chimiquement. En effet leurs propriétés, leurs applications et leur devenir dans l environnement sont intimement liés à leurs tailles, leurs charges et leurs comportements dans un milieu donné. Il est admis qu il y a un manque considérable d outils analytiques permettant une caractérisation suffisament exhaustive des CNT dans un échantillon donné. C est afin d apporter des réponses à ces questions que cette thèse a été réalisée. Elle a eu pour objectif de développer et d optimiser des méthodes basées sur l association de techniques de fractionnement par couplage flux-force ( Asymmetrical Flow Field-Flow Fractionation et Cyclical Electrical Field Flow Fractionation ) avec différents détecteurs comme l UV-Vis et la diffusion de lumière (MALS) pour la caractérisation des nanotubes de carbone dispersés en milieu aqueux. A travers la l évaluation des performances analytiques (en termes de justesse et de reproductibilité), les potentialités des différentes méthodologies développées dans ce travail de thèse et la pertinence des résultats obtenus qu elles permettent d obtenir ont été démontrées.The unique properties of Carbon Nanotubes (CNT) make them the subject of intensive research and development, and some companies such as high-tech industries have made them their priority in terms of production and use. To better understand and optimize their properties and applications, it is crucial to characterize them according to different physicochemical parameters. Indeed, their properties, applications and environmental fate are intimately linked to their sizes, charge and behavior in a given medium. It is recognized that there is a considerable lack of analytical tools and comprehensive study allowing to characterize CNT in a given sample. This work has been performed to provide answers to these questions. It aimed to develop and optimize methods based on hyphenation of Field Flow Fractionation techniques (Asymmetrical Flow Field-Flow Fractionation and Cyclical Electrical Field Flow Fractionation) to different detectors such as UV-Vis and light scattering (MALS) for the characterization of carbon nanotubes dispersed in aqueous media. The evaluation of the analytical performances (accuracy and reproductibility) allows the potentialities of all of the methods developed in this work as well as the relevance of the results that they give to be demonstrated.PAU-BU Sciences (644452103) / SudocSudocFranceF

6. Les micropolluants et les nanoparticules

Les « contaminants chimiques » sont des composés d’origine synthétique ou naturelle introduits dans l’environnement par l’activité humaine. Ils sont en nombre quasi illimité, car l'utilisation de molécules, à la fois dans l'industrie, dans l'agriculture ou par les individus, a abouti à la contamination généralisée de l'environnement et, notamment, des milieux aquatiques. Ces molécules, appelées « micropolluants » (en raison de leurs concentrations de l’ordre du microgramme par litre), se retr..