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

Measurement Bias on Nanoparticle Size Characterization by Asymmetric Flow Field-Flow Fractionation Using Dynamic Light-Scattering Detection

International audienceIn this work, we highlight the influence of the particle–particle interaction on the retention behavior in asymmetric flow field-flow fractionation (A4F) and the misunderstanding considering the size determination by a light-scattering detector (static and dynamic light scattering) by comparing fullerene nanoparticles to similar sized polystyrene nanoparticle standards. The phenomena described here suggest that there are biases in the hydrodynamic size and diffusion determination induced by particle–particle interactions, as characterized by their virial coefficient. The dual objectives of this paper are to (1) demonstrate the uncertainties resulting from the current practice of size determination by detectors coupled to an A4F system and (2) initiate a discussion of the effects of particle–particle interactions using fullerene nanoparticles on their characterization as well as their origins. The results presented here clearly illustrate that the simple diffusion coefficient equation that is generally used to calculate the hydrodynamic size of nanoparticles (NPs) cannot be considered for whole fractograms according to their size distribution. We tried to identify particle interactions that appear during fractionation and demonstrated using the fully developed diffusion coefficient equation. We postulate that the observed interaction-dependent retention behavior may be attributed to differences in the virial coefficient between NPs and between NPs and the accumulation wall (membrane surface) without quantifying it. We hope that our results will stimulate discussion and a reassessment of the size determination procedure by A4F-LS to more fully account for all the influential material parameters that are relevant to the fractionation of nanoscale particles by A4F

Polymer science for an overall study of micro and nanoplastic hazards: Sources, fate and effects

International audienceNovel samplers have been developed to sequester and conc. org. pollutant and contaminants. They differ from classic samplers by their unique geometry as a result of the manufg. technique. A droplet-​flow millifluidic process allowed precise control of the size and the geometry and the sensors have been called Diffusive Milligel Beads (DMG)​. DMG opens a lot of perspectives and opportunities in environmental monitoring. Developed in a first approach to detect heavy metal in soils, they are now dedicated to better understand the dynamic and the fate of nanoplastics (NPs) in freshwater and seawater. Not only is the toxicity of NPs of major concern, but also NPs assocd.-​toxicants. DMG are designed to give a comprehensive approach of the Trojan horse effect of nanoplastics (NPs)​. This term was recently used to warn the community about the notion of microplastic and a fortiori NPs concg. pollutants acquired from the surrounding environment and potentially releasing them into tissues or cells of the ingesting organism as bioavailable contaminants. The study includes an overall approach to address several issues: the elaboration of representative NPs in terms of size, size distribution, morphol. and chem. compn., the NPs characterization via hyphenated methods, and to the evaluation of the pollution level, the evaluation of the biodisponibility and the toxicity of metals mediated by NPs

An assessment of retention behavior for gold nanorods in asymmetrical flow field-flow fractionation

International audienceApplications of asymmetrical flow field-flow fractionation (AF4) continue to expand rapidly in the fields of nanotechnology and biotechnology. In particular, AF4 has proven valuable for the separation and analysis of particles, biomolecular species (e.g., proteins, bacteria) and polymers (natural and synthetic), ranging in size from a few nanometers to several micrometers. The separation of non-spheroidal structures (e.g., rods, tubes, etc.) with primary dimensions in the nanometer regime, is a particularly challenging application deserving of greater study and consideration. The goal of the present study was to advance current understanding of the mechanism of separation of rod-like nano-objects in the AF4 channel. To achieve this, we have systematically investigated a series of commercially available cetyltrimethylammonium bromide stabilized gold nanorods (AuNRs), with aspect ratios from 1.7 to 10. Results show clearly that the retention time is principally dependent on the translational diffusion coefficient of the AuNRs. Equations used to calculate translational and rotational diffusion coefficients (cylinder and prolate ellipsoid models) yield similarly good fits to experimental data. Well characterized gold nanorods (length and diameter by transmission electron microscopy) can be used as calibrants for AF4 measurements allowing one to determine the aspect ratio of nanorod samples based on their retention times

Nanoplastic from mechanically degraded primary and secondary microplastics for environmental assessments

International audienceDegradation of plastic waste in the environment leads to the formation of microplastics and nanoplastics. To better understand the fate, behavior and reactivity of nanoplastics, it is essential to conduct experiments with representative and well-characterized nanoplastics. In the present study, we provided a top down method based on mechanical degradation to obtain nanoplastics from both primary and secondary microplastics. These nanoplastics were then characterized in terms of size distribution, morphology and surface charge. It was found that they are highly polydisperse with different shapes and negatively charged surfaces and therefore very close to natural colloid characteristics. These nanoplastics may share similarities with environmental nanoplastics as referred to their chemical nature and morphology. Their physicochemical properties have been studied vs. salinity, pH and temperature

Trace element distribution in marine microplastics using laser ablation-ICPMS

International audienceDue to the dramatic quantity of plastic debris released into our environment, one of the biggest challenges of the next decades is to trace and quantify microplastics (MPs) in our environments, especially to better evaluate their capacity to transport other contaminants such as trace metals. In this study, trace elements (Fe, Cu, Zn, As, Cd, Sn, Sb, Pb, and U) were analyzed in the microplastic subsurface (200 μm) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Microplastics subjected to the marine environment were collected on beaches (Guadeloupe) exposed to the north Atlantic gyre. We established a strategy to discriminate sorbed contaminants from additives based on the metal concentration profiles in MP subsurface using qualitative and quantitative approaches. A spatiotemporal correlation of the sorption pattern was proposed to compare MPs in terms of relative exposure time and time-weighted average concentrations in the exposure media

Nanoplastics Identification in Complex Environmental Matrices: Strategies for Polystyrene and Polypropylene

International audienceIdentification of nanoplastics in complex environmental matrices remains a challenge. Despite the increase in nanoplastics studies, there is a lack of studies dedicated to nanoplastics detection, partially explained by their carbon-based structure, their wide variety of composition, and their low environmental concentrations compared to the natural organic matter. Here, pyrolysis coupled to a GCMS instrumental setup provided a relevant analytical response for polypropylene and polystyrene nanoplastic suspensions. Specific pyrolysis markers and their indicative fragment ions were selected and validated. Possible interferences with environmental matrices were explored by spiking nanoplastics in various organic matter suspensions (i.e., algae, soil natural organic matter, and soil humic acid) and analyzing an environmental suspension of nanoplastics. While a rapid polypropylene nanoplastics identification was validated, polystyrene nanoplastics require preliminary treatment. The strategies presented herein open new possibilities for the detection/identification of nanoplastics in environmental matrices such as soil, dust, and biota

Fate of nanoplastics in the environment: Implication of the cigarette butts

International audienceFate, transport and accumulation of nanoplastics have attracted considerable attention in the past few years. While actual researches have been focused on nanoplastics dispersed or aggregated in different environmental system, no study have been focused on the possibility that nanoplastics are co-transported with other natural or anthropogenic materials. Therefore, the large quantity of debris released in the environment, such as cigarette butts (CGB), could be part of the nanoplastics fate and behavior. Here we show the considerable sorption capacities of cigarette filters for nanoplastics. To address this topic, we chose polystyrene-based nanoplastics with similar state of charge (according to the physico-chemical characteristic of the zeta potential −45 to −40 mV) but with different sizes (50–800 nm) and morphologies. A kinetic approach to sorption in fresh water (pH = 8.05; 179.5 μS cm−1) at room temperature was carried out by means of the flow field flow analysis method (AF4) to determine the partition coefficients and water sampling rates between nanoplastics and cigarette butts. Using different models of, more or less environmentally relevant, nanoplastics (NPTs) and adequate analytical strategies, we found partition coefficients between the NPTs and CGBs ranged from 102 to 104 in freshwater conditions. We demonstrated that the physical features of the NPTs (size and morphology) have an influence on the sorption behaviour. Asymmetrical shaped NPTs with broader size distribution seems to be mostly retained in the CGBs after longer equilibration time. This result shows the importance of the NPTs features on the mechanisms governing their transfer and fate in the environment through environmental matrices, especially when other materials are involved. We anticipate our work to be a starting point for investigating the co-transport of NPTs with other materials present in the environment (natural and anthropogenic)

Asymmetrical flow field flow fractionation methods to characterize submicron particles: application to carbon-based aggregates and nanoplastics

cited By 0; Article in PressInternational audienceIn the last 10 years, asymmetrical flow field flow fractionation (AF4) has been one of the most promising approaches to characterize colloidal particles. Nevertheless, despite its potentialities, it is still considered a complex technique to set up, and the theory is difficult to apply for the characterization of complex samples containing submicron particles and nanoparticles. In the present work, we developed and propose a simple analytical strategy to rapidly determine the presence of several submicron populations in an unknown sample with one programmed AF4 method. To illustrate this method, we analyzed polystyrene particles and fullerene aggregates of size covering the whole colloidal size distribution. A global and fast AF4 method (method O) allowed us to screen the presence of particles with size ranging from 1 to 800 nm. By examination of the fractionating power Fd, as proposed in the literature, convenient fractionation resolution was obtained for size ranging from 10 to 400 nm. The global Fd values, as well as the steric inversion diameter, for the whole colloidal size distribution correspond to the predicted values obtained by model studies. On the basis of this method and without the channel components or mobile phase composition being changed, four isocratic subfraction methods were performed to achieve further high-resolution separation as a function of different size classes: 10–100 nm, 100–200 nm, 200–450 nm, and 450–800 nm in diameter. Finally, all the methods developed were applied in characterization of nanoplastics, which has received great attention in recent years

Deposition of environmentally relevant nanoplastic models in sand during transport experiments

International audienceNanoplastics (NPTs) are defined as colloids that originated from the unintentional degradation of plastic debris. To understand the possible risks caused by NPTs, it is crucial to determine how they are transported and where they may finally accumulate. Unfortunately, although most sources of plastic are land-based, risk assessments concerning NPTs in the terrestrial environmental system (soils, aquifers, freshwater sediments, etc.) have been largely lacking compared to studies concerning NPTs in the marine system. Furthermore, an important limitation of environmental fate studies is that the NPT models used are questionable in terms of their environmental representativeness. This study describes the fate of different NPT models in a porous media under unfavorable (repulsive) conditions, according to their physical and chemical properties: average hydrodynamic diameters (200–460 nm), composition (polystyrene with additives or primary polystyrene) and shape (spherical or polymorphic). NPTs that more closely mimic environmental NPTs present an inhomogeneous shape (i.e., deviating from a sphere) and are more deposited in a sand column by an order of magnitude. This deposition was attributed in part to physical retention, as confirmed by the straining that occurred for the larger size fractions. Additionally, different Derjaguin-Landau-Verwey-Overbeek (DLVO) models -the extended DLVO (XDLVO) and a DLVO modified by surface element integration (SEI) method-suggest that the environmentally relevant NPT models may alter its orientation to diminish repulsion from the sand surface and may find enough kinetic energy to deposit in the primary energetic minimum. These results point to the importance of choosing environmentally relevant NPT models