Cr(III) - Cr(VI): variability of the speciation of chromium released into the environment by microplastic weathering

International audienceThe use of Rare Earth Elements (REE) The pollution of the environment by an increasing amount of plastic waste is now well established. All environments, water, soil, atmosphere, are contaminated. Biodiversity is therefore potentially at risk, and it is now recognized that the environmental risk is not only due to the presence of plastics but also to their ability to transport and release contaminants, such as metals (1). Metals, both inorganic and organic, are widely used in the formulation of plastic as colorants, anti-oxidants, etc (2). Once released into the environment, plastics are degraded under natural conditions, resulting in the concomitant production of oxidized plastics particles (micro to nano-size) and the release of metallic additives (3). The speciation of metals and how they are trapped in the plastic matrix determine the species and amounts released into the environment.In a µXRF and µXAS study of long-term photo-oxidation altered polyethylene microplastics collected from the North Pacific gyre, we demonstrated that chromium (Cr) occurs as nanoparticles indifferently distributed or concentrated in pockets inside the polymer matrix. It can be associated with other metals such as titanium, cobalt and lead. Furthermore, different Cr(III) and Cr(VI) species were observed, resulting from the plastic formulation. Chromium nanoparticles are present in the core of plastics as well as in and on the surface of altered surface layers but its speciation is not modified in the altered areas.Therefore, under oceanic photo-oxidation, chromium can be released as toxic species, relative to its pristine speciation, with the fragmentation of weathered plastic debris.References:(1) Catrouillet C. et al. (2021) Metals in Microplastics: Determining Which Are Additive, Adsorbed, and Bioavailable. Sci. Process. Impacts, 23 (4), 553–558.(2) Hahladakis J. et al. (2018) An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. J. Hazard. Mat., 344, 179–199(3) Fotopoulou K.N., & Karapanagioti H.K. (2019) Degradation of Various Plastics in the Environment, in: The Handbook of Environmental Chemistry. Springer International Publishing, Cham, pp. 71–92increased in the last few decades, an

Impact Of The Polymer Degradation On The Metallic Additives Distribution In Microplastics

National audienceThe increasing production of plastics combined with the mismanagement of the plastic waste contributes to the creation of an environmental and health threat at a planetary scale. In addition to the alteration of plastic waste, the release of their additives and their fate remains unexplored. Although many studies focused on organic additives such as endocrine disruptors, few information is available on inorganic additives, especially on metals. These metallic additives can be released into the environment by degradation of the polymer matrices, becoming a new source of toxicity. To assess the impact of plastic degradation on the metallic additives' distribution and release, altered macroplastics (> 5 mm) were collected in the environment. By micro-XRF performed on a synchrotron line, colocalizations of metals were observed in the altered and unaltered layers of plastics. In the polyethylene plastics, metal additives are distributed as hotspot and large area as well as diffused elements. Statistical study analysis of the ratios between metals present in the non-altered and altered layers showed a preferential release of some metals. For a given additive some metals are released in greater quantity than the other. Plastics are therefore not only vectors, but also sources of metals in the environment

Impact Of The Polymer Degradation On The Metallic Additives Distribution In Microplastics

National audienceThe increasing production of plastics combined with the mismanagement of the plastic waste contributes to the creation of an environmental and health threat at a planetary scale. In addition to the alteration of plastic waste, the release of their additives and their fate remains unexplored. Although many studies focused on organic additives such as endocrine disruptors, few information is available on inorganic additives, especially on metals. These metallic additives can be released into the environment by degradation of the polymer matrices, becoming a new source of toxicity. To assess the impact of plastic degradation on the metallic additives' distribution and release, altered macroplastics (> 5 mm) were collected in the environment. By micro-XRF performed on a synchrotron line, colocalizations of metals were observed in the altered and unaltered layers of plastics. In the polyethylene plastics, metal additives are distributed as hotspot and large area as well as diffused elements. Statistical study analysis of the ratios between metals present in the non-altered and altered layers showed a preferential release of some metals. For a given additive some metals are released in greater quantity than the other. Plastics are therefore not only vectors, but also sources of metals in the environment

Impact Of The Polymer Degradation On The Metallic Additives Distribution In Microplastics

International audienceThe increasing production of plastics combined with the mismanagement of the plastic waste contributes to the creation of an environmental and health threat at a planetary scale. In addition to the alteration of plastic waste, the release of their additives and their fate remains unexplored. Although many studies focused on organic additives such as endocrine disruptors, few information is available on inorganic additives, especially on metals. These metallic additives can be released into the environment by degradation of the polymer matrices, becoming a new source of toxicity.To assess the impact of plastic degradation on the metallic additives’ distribution and release, altered macroplastics (> 5 mm) were collected in the environment. By micro-XRF performed on a synchrotron line, colocalizations of metals were observed in the altered and unaltered layers of plastics. In the polyethylene plastics, metal additives are distributed as hotspot and large area as well as diffused elements. Statistical study analysis of the ratios between metals present in the non-altered and altered layers showed a preferential release of some metals. For a given additive some metals are released in greater quantity than the other. Plastics are therefore not only vectors, but also sources of metals in the environment

Metals in microplastics: determining which are additive, adsorbed, and bioavailable

International audienceMicroplastics from the North Atlantic Gyre deposited on Guadeloupe beaches were sampled and characterized. A new method is developed to identify which elements were present as additives in these microplastics. The method used both acidic leaching and acidic digestion. Several elements (Al, Zn, Ba, Cu, Pb, Cd, Mn, Cr) were identified as pigments. Furthermore, some elements used as additives to plastics (especially the non-essential elements) seem to contribute to most of the acidic leaching, suggesting that these additives can leach and adsorb onto the surface microplastics, becoming bioavailable. Based on the acidic leaching element content, only Cd should represent a danger for fish when ingested. However, further studies are needed to determine the potential synergetic effect on health caused by the ingestion of several elements and microplastics

Cr(III) - Cr(VI): variability of the speciation of chromium released into the environment by microplastic weathering

International audienceThe use of Rare Earth Elements (REE) The pollution of the environment by an increasing amount of plastic waste is now well established. All environments, water, soil, atmosphere, are contaminated. Biodiversity is therefore potentially at risk, and it is now recognized that the environmental risk is not only due to the presence of plastics but also to their ability to transport and release contaminants, such as metals (1). Metals, both inorganic and organic, are widely used in the formulation of plastic as colorants, anti-oxidants, etc (2). Once released into the environment, plastics are degraded under natural conditions, resulting in the concomitant production of oxidized plastics particles (micro to nano-size) and the release of metallic additives (3). The speciation of metals and how they are trapped in the plastic matrix determine the species and amounts released into the environment.In a µXRF and µXAS study of long-term photo-oxidation altered polyethylene microplastics collected from the North Pacific gyre, we demonstrated that chromium (Cr) occurs as nanoparticles indifferently distributed or concentrated in pockets inside the polymer matrix. It can be associated with other metals such as titanium, cobalt and lead. Furthermore, different Cr(III) and Cr(VI) species were observed, resulting from the plastic formulation. Chromium nanoparticles are present in the core of plastics as well as in and on the surface of altered surface layers but its speciation is not modified in the altered areas.Therefore, under oceanic photo-oxidation, chromium can be released as toxic species, relative to its pristine speciation, with the fragmentation of weathered plastic debris.References:(1) Catrouillet C. et al. (2021) Metals in Microplastics: Determining Which Are Additive, Adsorbed, and Bioavailable. Sci. Process. Impacts, 23 (4), 553–558.(2) Hahladakis J. et al. (2018) An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. J. Hazard. Mat., 344, 179–199(3) Fotopoulou K.N., & Karapanagioti H.K. (2019) Degradation of Various Plastics in the Environment, in: The Handbook of Environmental Chemistry. Springer International Publishing, Cham, pp. 71–92increased in the last few decades, an

Impact Of The Polymer Degradation On The Metallic Additives Distribution In Microplastics

International audienceThe increasing production of plastics combined with the mismanagement of the plastic waste contributes to the creation of an environmental and health threat at a planetary scale. In addition to the alteration of plastic waste, the release of their additives and their fate remains unexplored. Although many studies focused on organic additives such as endocrine disruptors, few information is available on inorganic additives, especially on metals. These metallic additives can be released into the environment by degradation of the polymer matrices, becoming a new source of toxicity.To assess the impact of plastic degradation on the metallic additives’ distribution and release, altered macroplastics (> 5 mm) were collected in the environment. By micro-XRF performed on a synchrotron line, colocalizations of metals were observed in the altered and unaltered layers of plastics. In the polyethylene plastics, metal additives are distributed as hotspot and large area as well as diffused elements. Statistical study analysis of the ratios between metals present in the non-altered and altered layers showed a preferential release of some metals. For a given additive some metals are released in greater quantity than the other. Plastics are therefore not only vectors, but also sources of metals in the environment

Phenolic-Rich Extract from Almond (Prunus dulcis) Hulls Improves Lipid Metabolism in Triton WR-1339 and High-Fat Diet-Induced Hyperlipidemic Mice and Prevents Lipoprotein Oxidation: A Comparison with Fenofibrate and Butylated Hydroxyanisole

Hyperlipidemia and oxidative stress are risk factors for atherosclerosis. In this study, we investigated the hypolipidemic and anti-lipoprotein oxidation activities of polyphenol-rich extracts from almond hulls using Triton WR-1339 and high-fat diet-induced hyperlipemic mice as experimental models. We demonstrated that the almond hull extract significantly reduced total cholesterol, triglycerides and low-density lipoprotein-related plasma cholesterol (LDL-C) in the two experimental models of hyperlipidemia, but significantly increased high-density lipoprotein-related plasma cholesterol (HDL-C). Another beneficial effect of the extract was its ability to reduce the atherogenic index and LDL-C/HDL-C ratio. However, the extract exhibited effective antiradical activity against 2,2-diphenyl-1-picrylhydrazyl and significantly protected lipoprotein-rich plasma from mice against oxidation induced by copper ion. The extract contains 342.63±3.44 mg/g total phenolics, 144.67±6.83 mg/g tannins, and 20.66±0.92 mg/g flavonoids. These finding indicate that almond hulls contain polar products able to lower plasma lipid concentrations and which might be beneficial for the treatment of hyperlipidemia and prevention of atherosclerosis

Condition of Composted Microplastics After They Have Been Buried for 30 Years: Vertical Distribution in the Soil and Degree of Degradation

International audienceMicroplastics in soils are a growing concern. Composting household wastes can introduce microplastics to agroecosystems, because when unsorted compost is used as a fertilizer, the plastic debris it contains degrades to microplastics. This paper examines the distribution and degradation of microplastics in agricultural soil samples to investigate their potential mobility. The source of microplastics was a household waste compost added to the soil more than 30 years before the study. The microplastics were sorted from a plot-composite soil and characterised by Attenuated Total Reflectance combined with Fourier transform infrared spectroscopy (ATR-FTIR). The microplastics are present in the cultivated depth but have not been transferred deeper (2.9 g kg-1 in the 0–5 cm soil depth against 0.9 g kg-1 in the 30–35 cm soil depth). Polyethylene (PE), polypropylene (PP), polystyrene (PS) and Polyvinylchloride (PVC) were identified in the forms of heterogeneous fragments, films, and fibres and accounted for 90% of the total microplastics. Advanced degradation observed was mainly assumed to be due to composting, though the plastic may have degraded further in the soil matrix. Highly degraded plastics are a greater danger for further leaching of contaminants into soil and our food supply

Do nanoplastics impact Pb up-taking by Hordeum vulgare L.?

International audienceMost studies on nanoplastics (NPs) focus on aquatic environments, overlooking their combined bioaccumulation with pollutants in terrestrial ecosystems. This study addresses a part of this gap by investigating how polystyrene nanoplastics (PS-NPs) affect the bioaccumulation and translocation of lead (Pb) in Hordeum vulgare L. plants. Using the RHIZOtest device for precise soil contamination control, we quantified PS-NPs (50 nm) in plant shoots via pyrolysis-gas chromatography/mass spectrometry (Py-GCMS) after plant KOH digestion. Our findings revealed that PS-NPs reduce Pb bioaccumulation and make adsorbed Pb onto PS-NPs less bioavailable to plants. For the highest Pb concentration, the Pb uptake index (PUI) followed the trend: Free Pb > NPs + Pb > Pb primary adsorbed by NPs, showing reduced Pb translocation to shoots in the presence of PS-NPs. Moreover, the presence of Pb decreased the bioavailability of PS-NPs probably in response to PS-NPs aggregation or modified charge. The PS-NPs concentrations in shoots range from 275.2 to 400 μg g−1, representing 3.9 to 5.75% of the total PS-NPs. This study highlights the intricate interactions between nanoplastics and metals in soil-plant systems and emphasizes the need for further research on their combined effects and potential risks to food safety