Letteratura scientifica selezionata sul tema "Plastics – Toxicology"
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Articoli di riviste sul tema "Plastics – Toxicology"
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Glausiusz, Josie. "Toxicology: The plastics puzzle". Nature 508, n. 7496 (aprile 2014): 306–8. http://dx.doi.org/10.1038/508306a.
Testo completo
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Brander, Susanne M., Rachel E. Fontana, Tawny M. Mata, Sarah A. Gravem, Annaliese Hettinger, Jessica R. Bean, Amber I. Szoboszlai, Carol A. Keiper e Meghan E. Marrero. "The Ecotoxicology of Plastic Marine Debris". American Biology Teacher 73, n. 8 (1 ottobre 2011): 474–78. http://dx.doi.org/10.1525/abt.2011.73.8.9.
Testo completoAbstract (sommario):
The accumulation of plastic in the oceans is an ever-growing environmental concern. Plastic debris is a choking and entanglement hazard for wildlife; plastics also leach toxic compounds into organisms and ecosystems. Educating students about the marine debris problem introduces fundamental concepts in toxicology, ecology, and oceanography. Students will learn about the toxicity of plastics, collect and analyze data on plastic debris, and put their new knowledge to work by writing a congressional bill that addresses the problem of marine debris.
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Mikula, P., Z. Svobodová e M. Smutná. "Phthalates: toxicology and food safety – a review". Czech Journal of Food Sciences 23, No. 6 (15 novembre 2011): 217–23. http://dx.doi.org/10.17221/3394-cjfs.
Testo completoAbstract (sommario):
Phthalates are organic substances used mainly as plasticisers in the manufacture of plastics. They are ubiquitous in the environment. Although tests in rodents have demonstrated numerous negative effects of phthalates, it is still unclear whether the exposure to phthalates may also damage human health. This paper describes phthalate toxicity and toxicokinetics, explains the mechanisms of phthalate action, and outlines the issues relating to the presence of phthalates in foods.
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Seo, Chan, Joo Won Lee, Won-Kyo Jung, Yoon-Mi Lee, Seungjun Lee e Sang Gil Lee. "Examination of Microcystin Adsorption by the Type of Plastic Materials Used during the Procedure of Microcystin Analysis". Toxins 14, n. 9 (7 settembre 2022): 625. http://dx.doi.org/10.3390/toxins14090625.
Testo completoAbstract (sommario):
The incidence of eutrophication is increasing due to fertilizer abuse and global warming. Eutrophication can induce the proliferation of cyanobacteria such as Microcystis, which produces microcystins. Microcystins are toxic to specific organs such as the liver and the heart. Thus, monitoring of microcystins is strongly required to control drinking water and agricultural product qualities. However, microcystins could be adsorbed by plastic materials during sample storage and preparation, hindering accurate analysis. Therefore, the current study examined the recovery rate of microcystins from six plastics used for containers and eight plastics used for membrane filters. Among the six plastics used for containers, polyethylene terephthalate showed the best recovery rate (≥81.3%) for 48 h. However, polypropylene, polystyrene, and high- and low-density polyethylenes showed significant adsorption after exposure for 1 hr. For membrane materials, regenerated cellulose (≥99.3%) showed the highest recovery rate of microcystins, followed by polyvinylidene fluoride (≥94.1%) and polytetrafluoroethylene (≥95.7%). The adsorption of microcystins appeared to be strongly influenced by various molecular interactions, including hydrophobic interaction, hydrogen bonding, and electrostatic interaction. In addition, microcystins’ functional residues seemed to be critical factors affecting their adsorption by plastic materials. The present study demonstrates that polyethylene terephthalate and regenerated cellulose membrane are suitable plastic materials for the analysis of microcystins.
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Valentine, Katey L., e Alistair B. A. Boxall. "Interactions Between Plastic, Microbial Biofilms and Gammarus pulex: An Initial Investigation". Bulletin of Environmental Contamination and Toxicology 108, n. 4 (6 gennaio 2022): 609–15. http://dx.doi.org/10.1007/s00128-021-03448-5.
Testo completoAbstract (sommario):
AbstractThere is increasing evidence that microbial biofilms which form on the surface of marine plastics can increase plastics palatability, making it more attractive to organisms. The same information, however, does not exist for freshwater systems. This study observed the response of the freshwater amphipod Gammarus pulex when exposed to 3 cm-diameter discs of biofilm-covered plastic, both alone and when presented alongside its natural food. G. pulex did not fragment or consume the plastic materials, and the presence of colonised plastic in the immediate environment did not alter the amount of time organisms spent interacting with their natural food. This study provides baseline information for virgin and microbially colonised low-density polyethylene and polylactic acid film. Further studies, with other types of plastic possessing different physical properties and with different microbial biofilm compositions are now required to build further understanding of interactions between plastic, microbial biofilms, and freshwater shredding invertebrates.
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Mosconi, Giacomo, Sara Panseri, Stefano Magni, Renato Malandra, Alfonsina D’Amato, Marina Carini, Luca Chiesa e Camilla Della Torre. "Plastic Contamination in Seabass and Seabream from Off-Shore Aquaculture Facilities from the Mediterranean Sea". Journal of Xenobiotics 13, n. 4 (25 ottobre 2023): 625–40. http://dx.doi.org/10.3390/jox13040040.
Testo completoAbstract (sommario):
We characterized the presence of plastics in different organs of the gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) from some off-shore aquaculture facilities of the Mediterranean Sea. Plastics were detected in 38% of analyzed fish. Higher contamination was observed in fish from Turkey and Greece with respect to Italy, without significant differences between the geographical areas. Plastics accumulated mostly in the gastrointestinal tract and, to a lower extent, in the muscle, which represents the edible part of fish. Based on the particle detected, a maximum amount of 0.01 plastic/g wet weight (w.w.) can occur in muscles, suggesting a low input for humans through consumption. A large portion of the particles identified was represented by man-made cellulose-based fibers. The characterization of the polymeric composition suggests that plastics taken up by fish can have land-based and pelagic origins, but plastics can be introduced also from different aquaculture practices.
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Dube, Edith, e Grace Emily Okuthe. "Plastics and Micro/Nano-Plastics (MNPs) in the Environment: Occurrence, Impact, and Toxicity". International Journal of Environmental Research and Public Health 20, n. 17 (28 agosto 2023): 6667. http://dx.doi.org/10.3390/ijerph20176667.
Testo completoAbstract (sommario):
Plastics, due to their varied properties, find use in different sectors such as agriculture, packaging, pharmaceuticals, textiles, and construction, to mention a few. Excessive use of plastics results in a lot of plastic waste buildup. Poorly managed plastic waste (as shown by heaps of plastic waste on dumpsites, in free spaces, along roads, and in marine systems) and the plastic in landfills, are just a fraction of the plastic waste in the environment. A complete picture should include the micro and nano-plastics (MNPs) in the hydrosphere, biosphere, lithosphere, and atmosphere, as the current extreme weather conditions (which are effects of climate change), wear and tear, and other factors promote MNP formation. MNPs pose a threat to the environment more than their pristine counterparts. This review highlights the entry and occurrence of primary and secondary MNPs in the soil, water and air, together with their aging. Furthermore, the uptake and internalization, by plants, animals, and humans are discussed, together with their toxicity effects. Finally, the future perspective and conclusion are given. The material utilized in this work was acquired from published articles and the internet using keywords such as plastic waste, degradation, microplastic, aging, internalization, and toxicity.
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Zhang, Haigang, Yilin Hou, Wenjin Zhao e Hui Na. "Control Strategies of Plastic Biodegradation through Adjusting Additives Ratios Using In Silico Approaches Associated with Proportional Factorial Experimental Design". International Journal of Environmental Research and Public Health 19, n. 9 (6 maggio 2022): 5670. http://dx.doi.org/10.3390/ijerph19095670.
Testo completoAbstract (sommario):
Plastics, as a polymer material, have long been a source of environmental concern. This paper uses polystyrene plastics as the research object, and the relative contribution of each component of plastic additives to plastic degradation is screened using the molecular dynamics method. The factorial experimental design method is combined with molecular dynamics simulation to adjust the additive composition scheme, analyze the mechanism of interaction between the additive components, and select the plastic additive combination that is most readily absorbed and degraded by microorganisms. Seven different types of plastic additives, including plasticizers, antioxidants, light and heat stabilizers, flame retardants, lubricants, and fillers, are chosen as external stimuli affecting the biodegradability of plastics. Using molecular dynamics simulation technology, it is demonstrated that plastic additives can promote the biodegradability of plastics. The factorial experimental design analysis revealed that all plastic additives can promote plastic biodegradation and plasticizer is the most favorable factor affecting plastic degradation, that hydrophobicity interactions are the primary reason for enhancing plastic degradation, and that screening No. 116–45 (plasticizer A, light stabilizer C, flame retardant E) is the most advantageous combination of biodegradable plastic additives. The plastic biodegradation effect regulation scheme proposed in this study is based on optimizing the proportion of additive components. To continue research on aquatic biodegradable plastics, the optimal combination of plastic components that can be absorbed and degraded by microorganisms is recommended.
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Shen, Maocai, Biao Song, Guangming Zeng, Yaxin Zhang, Wei Huang, Xiaofeng Wen e Wangwang Tang. "Are biodegradable plastics a promising solution to solve the global plastic pollution?" Environmental Pollution 263 (agosto 2020): 114469. http://dx.doi.org/10.1016/j.envpol.2020.114469.
Testo completo
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Knill, Charles J., e John F. Kennedy. "Food additive toxicology". Carbohydrate Polymers 31, n. 4 (dicembre 1996): 294–95. http://dx.doi.org/10.1016/s0144-8617(97)89842-6.
Testo completoTesi sul tema "Plastics – Toxicology"
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Konkol, Lidia, e lkonkol77@hotmail com. "Contaminant levels in recycled PET plastic". Swinburne University of Technology. Environment and Biotechnology Centre, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20051025.142051.
Testo completoAbstract (sommario):
The purpose of this thesis was to determine which contaminants were present in washed and dried shredded poly(ethylene terephthalate) (PET, flake) obtained from curbside collection and to determine whether their concentrations were above the US FDA threshold of 215 ppb. Over thirty semi-volatile contaminants were extracted from the treated flake by Soxhlet extraction using dichloromethane as a PET swelling solvent and gas chromatography-mass spectroscopy for identification and quantification. Soxhlet extraction of flake ground to 0-300 �m was effectively completed by 24 h, whereas sonication reduced the extraction time to 3 h. In contrast Soxhlet extractions on flake ground to a larger particle size range (>300-425 �m and >425-700 �m) were completed within four hours, possibly due to less aggregation in the extraction thimble. In the finely ground flake (0-300 �m) the levels of most contaminants were below 215 ppb, but six were not. Dodecanoic acid was present at about 1200 ppb, 2-butoxyethanol was approximately 1000 ppb, limonene, benzophenone and methylsalicylate were above 800 ppb and 2-methylnaphthalene near 215 ppb. After analogous method development the levels of all diffusible compounds in extruded PET pellets were below the threshold of 215 ppb.
The Soxhlet extraction technique was validated by comparison with total dissolution by TFA for two of the three particle size ranges obtained by grinding the PET flake (>300-425 �m and >425-700 �m) and for the unground flake. Further validation was achieved by the comparison of contaminant levels determined by total dissolution with TFA and sonication with DCM using flake ground to the 0-300 �m size range. The levels of contaminants were found to increase with decreasing particle size range, but XRD measurements of degrees of crystallinity were similar for each PET particle size range, thus showing that the differences in contaminant levels were not due to variable percentages of the amorphous material from the tops and bottoms of shredded bottles, relative to the amounts of crystalline PET from the mid-sections of the bottles. Hence it was postulated that the variations in contaminant levels were due to selective grinding of the more highly contaminated surfaces, whilst the larger particles incorporated the less contaminated interior material.
The analysis of the more homogenous annealed (extruded) pellets indicated that contaminant levels between the analogous particle size ranges were equivalent. This observation validated our interpretation of the high levels of contaminants found in finely ground flake being due to selective surface grinding where high levels are expected. When analysing volatiles, static headspace analysis was performed on flake and extruded pellets due to the limitations surrounding SPME. External standardisation was used as the method of quantification and the levels of toluene, undecane and p-xylene in extruded pellets were found to be below 38 ppb and therefore within the 215 ppb FDA-set threshold for flake and pellets.
2
Nalli, Sandro. "Biodegradation of plasticizers : characterization and toxicity of their metabolites". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31062.
Testo completoAbstract (sommario):
More than one billion pounds of plasticizers are produced each year to supply the plastics industry. Some of these plasticizers, particularly phthalates, are suspected endocrine disruptors. However, few studies have been conducted to determine if they are susceptible to biodegradation by naturally occurring bacteria once they are released into the environment.Six organisms were tested for their ability to grow in the presence of six different industrial plasticizers. Two bacteria, Rhodococcus rhodochrous and Arthrobacter paraffineus, grew well in media containing n-hexadecane and one of the plasticizers.
Fermentations in a 2-liter reactor were performed with Rhodococcus rhodochrous and three plasticizers: bis 2-ethylhexyl adipate, dioctyl phthalate and dioctyl terephthalate. The organism degraded all of the adipate, half of the terephthalate was degraded and the phthalate was degraded slightly.
In these growth studies, the toxicity of the media increased as the organism grew. This trend was linked to the accumulation of metabolites from the partial degradation of the plasticizer. The two major metabolites were identified as 2-ethyl hexanol and 2-ethyl hexanoic acid. The alcohol was only observed part way through the growth in the presence of the adipate. Its concentration decreased as it was oxidized to the acid and it was not present at the end of the fermentation.
The acid was observed for all three types of plasticizers and it was present in high concentrations at the end of every experiment. The nature and pattern of production of the metabolites were consistent with a pathway for the degradation of all three plasticizers by hydrolysis of the ester bonds.
The accumulation of toxic metabolites indicates that biodegradation may not be a solution to reducing environmental impacts associated with plasticizers that have leached into the environment.
3
Adkins, Sasha. "From Disposable Culture to Disposable People: Teaching About the Unintended Consequences of Plastics". Antioch University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1513941070990328.
Testo completo
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Vigren, David. "Migration of Xenoestrogens from Plastic Food Containers during Cooking". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-43957.
Testo completoAbstract (sommario):
Xenoestrogens are compounds, foreign from the body, that can enter cells and interact with the estrogen receptors (ER) to produce an estrogenic response. Many additives used in plastics are compounds with estrogenic activity. Some of these additives are known to slowly leach from the plastics. When using plastic containers as lunchboxes for reheating or food storage, these additives can leach from the plastics and end up in the food. In this project, food simulates were cooked in six different thermoplastic containers, made of polypropylene, in an oven at 100 °C for 15 minutes. Three of the thermoplastic containers were lunchboxes marketed to be able to withstand cooking in a microwave. The other three were provisional lunchboxes made from various food storing containers originally made for refrigeration purposes. The estrogenic activity in the different samples was measured using an ER-CALUX in vitro assay. The results were measured in 17β-estradiol equivalent (Bio-EEQ) values in pg/ml. The purpose of this project was to investigate whether or not these plastic containers leach xenoestrogens that can be measured with an ER-CALUX assay, and compare the results with the results from other existing toxicological studies, and also to see if there is a difference in Bio-EEQ levels between the plastic containers made for microwave usage and those made for refrigerated purposes. The results from this project indicate that most of these plastic containers do leach estrogenic compounds that can be detected in the ER-CALUX, even the ones made for microwave usage. Fortunately, compared to other toxicological studies, the Bio-EEQ levels in these food samples cooked in plastic containers are low. However the potential adverse effects in prenatally exposed children cannot be ignored as other studies have shown that very low levels of xenoestrogens are enough to potentially cause a disturbance in the reproductive development and fertility.
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Hindman, Andrea R. "The mechanisms of BPA exposure and in the developing mammary gland". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503321233777122.
Testo completo
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Kedzierski, Mikaël. "Pollutions du milieu littoral par les microplastiques : Méthodes d’évaluation". Thesis, Lorient, 2017. http://www.theses.fr/2017LORIS464/document.
Testo completoAbstract (sommario):
Les plastiques sont des matériaux techniques nécessaires au fonctionnement des sociétés industrialisées. Cependant, au début des années 2000, des particules de plastique de l’ordre de la dizaine de microns sont observées dans des échantillons d’eau de mer. Ce sont des « microplastiques ». Leur présence dans la plupart des milieux a progressivement été mise en lumière au point d’en faire un marqueur de l’anthropocène. Par ailleurs, ces particules interagissent avec leur environnement et peuvent être vectrices d’additifs toxiques ou de micropolluants. Face aux risques que représentent ces particules, il est important de pouvoir évaluer leur dangerosité pour l’homme et les écosystèmes. Dans ce contexte, les objectifs de ce travail de thèse sont (1) de déterminer les conditions d’extraction des microplastiques présents dans le sable les plus efficaces et les moins coûteuses et (2) de traduire en terme de toxicité les interactions entre micropolluants et plastiques vieillis dans le milieu marin. Pour cela, un prototype de système d’élutriation a été construit et un protocole adapté a été mis en place pour permettre d’extraire les microplastiques du sable. Afin de faciliter la détermination des vitesses de flux optimales pour permettre une élutriation efficace, un modèle numérique simple reposant sur des équations d’hydrodynamique a été développé. La confrontation des résultats théoriques et expérimentaux a ensuite permis de le valider. Ces résultats ont également permis de mettre en évidence que des ajustements du dimensionnement du système d’élutriation étaient nécessaires. En se basant sur différentes contraintes, par exemple sur le temps nécessaire pour réaliser l’élutriation ou encore sur la taille de la colonne, de nouvelles données de dimensionnement ont été acquises. Le vieillissement de 3 types de plastique (PVC, PET et PBAT) dans le port de Kernevel (Larmor- Plage) a été étudié en suivant l’évolution de l’état de surface et la toxicité de ces matériaux durant 502 jours d’immersion. Cette étude a montré des comportements très différents de ces trois plastiques au cours du temps. Ainsi, le PBAT vieillit plus vite que le PVC alors que le PET évolue peu. Le vieillissement du PVC s’accompagne d’une perte de ses composés à activité œstrogénique et d’une adsorption de métaux lourds. En milieu marin, en se dégradant la surface du PBAT forme des cavités dans lesquelles se piègent des argiles ; de plus en vieillissant ce matériau peut présenter une forte activité œstrogénique ponctuellePlastics are technical materials necessary for industrialized societies. However, in the early 2000s, plastic particles of about ten microns were observed in seawater samples. These are called "microplastics". Their presence in most environments has been progressively highlighted making it an anthropocene marker. Moreover, these particles interact with environments and may carry toxic additives or micropollutants. However, scientific and technical barriers limit this accurate evaluation. In this context, the aims of this work are (1) to determine the most efficient and cost- effective extraction conditions of microplastics trapped in sand and (2) to evaluate the toxicity due to the interactions between micropollutants and aged plastics, which can occur in the marine environment. Thus, an elutriation system prototype has been built and an adapted protocol developed to efficiently extract microplastics from sand. In order to determine the optimal elutriation flow velocities, a simple numerical model based on hydrodynamic equations has been developed. This numerical model has been validated by comparing theoretical and experimental results. However, these results also demonstrate that process optimization was required: based on different constraints, for example the time needed to achieve the elutriation or the size of the column, new data on the design have been acquired. The evolution of the surface state and the toxicity of 3 types of plastic (PVC, PET and PBAT) immersed in the marine environment during 550 days was studied on Kernevel harbor (Larmor-Plage, France). The results of the plastics ageing show very different behaviors. PBAT ages faster than PVC whereas PET does not exhibit large modifications. The aging of PVC is accompanied by a loss of compounders characterized by an estrogenic activity and by the adsorption of heavy metals. In the marine environment, the degradation of the PBAT surface forms cavities in which clay particles can be trapped. Moreover, in a more punctual manner than PVC, this material exhibit strong estrogenic activities
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Kedzierski, Mikaël. "Pollutions du milieu littoral par les microplastiques : Méthodes d’évaluation". Electronic Thesis or Diss., Lorient, 2017. http://www.theses.fr/2017LORIS464.
Testo completoAbstract (sommario):
Les plastiques sont des matériaux techniques nécessaires au fonctionnement des sociétés industrialisées. Cependant, au début des années 2000, des particules de plastique de l’ordre de la dizaine de microns sont observées dans des échantillons d’eau de mer. Ce sont des « microplastiques ». Leur présence dans la plupart des milieux a progressivement été mise en lumière au point d’en faire un marqueur de l’anthropocène. Par ailleurs, ces particules interagissent avec leur environnement et peuvent être vectrices d’additifs toxiques ou de micropolluants. Face aux risques que représentent ces particules, il est important de pouvoir évaluer leur dangerosité pour l’homme et les écosystèmes. Dans ce contexte, les objectifs de ce travail de thèse sont (1) de déterminer les conditions d’extraction des microplastiques présents dans le sable les plus efficaces et les moins coûteuses et (2) de traduire en terme de toxicité les interactions entre micropolluants et plastiques vieillis dans le milieu marin. Pour cela, un prototype de système d’élutriation a été construit et un protocole adapté a été mis en place pour permettre d’extraire les microplastiques du sable. Afin de faciliter la détermination des vitesses de flux optimales pour permettre une élutriation efficace, un modèle numérique simple reposant sur des équations d’hydrodynamique a été développé. La confrontation des résultats théoriques et expérimentaux a ensuite permis de le valider. Ces résultats ont également permis de mettre en évidence que des ajustements du dimensionnement du système d’élutriation étaient nécessaires. En se basant sur différentes contraintes, par exemple sur le temps nécessaire pour réaliser l’élutriation ou encore sur la taille de la colonne, de nouvelles données de dimensionnement ont été acquises. Le vieillissement de 3 types de plastique (PVC, PET et PBAT) dans le port de Kernevel (Larmor- Plage) a été étudié en suivant l’évolution de l’état de surface et la toxicité de ces matériaux durant 502 jours d’immersion. Cette étude a montré des comportements très différents de ces trois plastiques au cours du temps. Ainsi, le PBAT vieillit plus vite que le PVC alors que le PET évolue peu. Le vieillissement du PVC s’accompagne d’une perte de ses composés à activité œstrogénique et d’une adsorption de métaux lourds. En milieu marin, en se dégradant la surface du PBAT forme des cavités dans lesquelles se piègent des argiles ; de plus en vieillissant ce matériau peut présenter une forte activité œstrogénique ponctuellePlastics are technical materials necessary for industrialized societies. However, in the early 2000s, plastic particles of about ten microns were observed in seawater samples. These are called "microplastics". Their presence in most environments has been progressively highlighted making it an anthropocene marker. Moreover, these particles interact with environments and may carry toxic additives or micropollutants. However, scientific and technical barriers limit this accurate evaluation. In this context, the aims of this work are (1) to determine the most efficient and cost- effective extraction conditions of microplastics trapped in sand and (2) to evaluate the toxicity due to the interactions between micropollutants and aged plastics, which can occur in the marine environment. Thus, an elutriation system prototype has been built and an adapted protocol developed to efficiently extract microplastics from sand. In order to determine the optimal elutriation flow velocities, a simple numerical model based on hydrodynamic equations has been developed. This numerical model has been validated by comparing theoretical and experimental results. However, these results also demonstrate that process optimization was required: based on different constraints, for example the time needed to achieve the elutriation or the size of the column, new data on the design have been acquired. The evolution of the surface state and the toxicity of 3 types of plastic (PVC, PET and PBAT) immersed in the marine environment during 550 days was studied on Kernevel harbor (Larmor-Plage, France). The results of the plastics ageing show very different behaviors. PBAT ages faster than PVC whereas PET does not exhibit large modifications. The aging of PVC is accompanied by a loss of compounders characterized by an estrogenic activity and by the adsorption of heavy metals. In the marine environment, the degradation of the PBAT surface forms cavities in which clay particles can be trapped. Moreover, in a more punctual manner than PVC, this material exhibit strong estrogenic activities
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Cheng, Jingguang. "Microplastics in the marine environment : an ecotoxicological perspective". Electronic Thesis or Diss., Sorbonne université, 2020. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2020SORUS025.pdf.
Testo completoAbstract (sommario):
La pollution plastique océanique est l’une préoccupation majeure de notre siècle, avec plusieurs millions de tonnes de plastique déversées dans l'océan chaque année qui menacent la santé des écosystèmes. Les effets des plastiques ont été identifiés à tous les niveaux de la chaîne trophique, du zooplancton à la mégafaune, mais leurs effets sur la vie des microorganismes et sur leur rôle crucial dans le fonctionnement de l'écosystème océanique restent méconnus. L'objectif de cette thèse était d'étudier l'écotoxicité des plastiques en milieu marin. La première question traitée était : dans quelle mesure l'abondance, la diversité et l'activité de la vie bactérienne se développant sur le plastique, nommée «plastisphère», sont influencées par les propriétés chimiques du polymère et les changements environnementaux (chapitre 2)? Ce point a été abordé en immergeant pendant 2 mois dans l'eau de mer du Polyéthylène (PE), de l’acide polylactide (PLA) ainsi que du verre comme témoin, sous différentes formes : méso-débris (18 mm de diamètre), grands microplastiques (LMP; 3 mm de diamètre), et petits microplastiques (SMP; de 100 µm de diamètre de formes sphériques et irrégulières). Nous avons constaté que la composition chimique du plastique, les phases successives de formation du biofilm et les interactions phytoplancton-bactéries étaient des facteurs déterminants de l'abondance, de la diversité et de l'activité de la plastisphère a contrario de la taille et à la forme du matériau.La deuxième question traitée était : le microplastique (polystyrène PS; 50-100 µm; trois concentrations) ainsi que leur biofilm mature seraient-ils toxiques pour le filtre-filtreur marin Branchiostoma lanceolatum et dans quelles mesures la plastisphère peut-elle influencer cette toxicité (chapitre 3)? Nous avons utilisé un large éventail de techniques complémentaires pour suivre l'ingestion des microplastiques (quantification microscopique) à l’origine d’une potentielle modification du microbiote intestinal de l’hôte (séquençage 16S rRNA Illumina Miseq). La réponse physiologique de l’hôte a également été suivie au travers de l’expression génique du système immunitaire, du stress oxydatif et de l’apoptose (Nanostring) ainsi que par histopathologie ( La microscopie électronique à transmission). Aucune toxicité évidente n'a été observée, alors que les microplastiques pourraient être un vecteur de modification du microbiome intestinal, et qu’une plus grande différenciation des cellules a été observée au niveau des tissus intestinaux. La troisième question traitée était: Existe-t-il des alternatives aux microbilles pétrochimiques conventionnels utilisées en cosmétique biodégradables en milieu marin? (Chapitre 4). Nous avons utilisé une approche multidisciplinaire pour suivre les 4 étapes de biodégradation dont la 1/biodétérioration (granulométrie, gravimétrie et spectroscopie FTIR), 2/la biofragmentation (chromatographie d'exclusion de taille, résonance magnétique nucléaire 1H et spectrométrie de masse à haute résolution), 3/la bioassimilation et 4/la minéralisation (résonance magnétique nucléaire 1H et mesures de l'oxygène) sur différentes formes de microbilles en présence de bactéries marines. Après 60 jours d’incubation, nos résultats ont permis d’identifier des microbilles de polyhydroxybutyrate-co-hydroxyvalérate (PHBV) ou de riz et dans une moindre mesure de polycaprolactone (PCL) et d'abricot comme alternatives aux microplastiques conventionnels, en PE ou en polyméthacrylate de méthyle (PMMA) non biodégradés dans nos conditions. Fait remarquable, le PLA biosourcé n'était pas biodégradable, mais le PCL pétrochimique était biodégradable dans nos conditions marinesOceanic plastic pollution is of major concern, with several million tons of plastic dumped in the ocean every year that are causing health threat to marine creatures. Impacts have been found at all the trophic chain levels from the zooplankton to the megafauna, but little is known on its impact on the microbial life and its crucial role in the oceanic ecosystem functioning. The objective of this thesis was to study the ecotoxicity of plastics in the marine environment. The first handled question was: how much the abundance, diversity and activity of bacterial life growing on plastic, i.e. the ‘plastisphere’ are driven by the chemical properties of the polymer and the environmental changes (Chapter 2)? Polyethylene (PE) and polylactide acid (PLA) together with glass controls in the forms of meso-debris (18mm diameter) and large-microplastics (LMP; 3mm diameter), as well as small-microplastics (SMP; of 100 m diameter with spherical and irregular shapes) were immerged during 2 months in seawater. We found that the plastic chemical composition, the successive phases of biofilm formation and the phytoplankton-bacteria interactions were more important factors driving the abundance, diversity and activity of the plastisphere as compared to material size and shape. The second handled question was: would the microplastic (polystyrene PS; 50-100 µm; three concentrations) together with their mature biofilm be toxic for the marine filter-feeder Branchiostoma lanceolatum and how much the plastisphere can influence this toxicity (Chapter 3)? We used a large set of complementary techniques to follow the microplastic ingestion (microscopy quantification) and the modification of the gut microbiota (16S rRNA Illumina Miseq sequencing), the gene expression of immune system, oxidative stress and apoptosis (Nanostring) and also histopathology (transmission electron microscopy). No obvious toxicity was observed, while microplastics could be a vector for bacteria to the gut microbiome, can induce more goblet cell differentiation and can surprisingly have a positive effect by supplying nutrients to amphioxus in the form of bacteria and diatoms from the plastisphere. The third handled question was: how much the conventional petroleum-based microbeads classically used in cosmetics can be substituted by other polymers for their biodegradability by the plastisphere in marine environment? (Chapter 4). We used complementary techniques to follow the 4 biodegradation steps including biodeterioration (granulometry, gravimetry and FTIR spectroscopy), biofragmentation (size exclusion chromatography, 1H nuclear magnetic resonance and high-resolution mass spectrometry), bioassimilation and mineralization (1H nuclear magnetic resonance and oxygen measurements). We concluded that microbeads made of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) or rice and in a lesser extend polycaprolactone (PCL) and apricot were good candidates for substitution of conventional microplastics, classically made of PE or polymethyl methacrylate (PMMA) that were not biodegraded under our conditions. Interestingly, the biobased PLA was not biodegradable but the petroleum-based PCL was biodegradable under our marine conditions
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Songue, Same Olivier. "Dynamique des usages des récipients plastiques et étude du transfert des bisphénols et phtalates vers les matrices alimentaires". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILS010.
Testo completoAbstract (sommario):
Les récipients plastiques sont soit alimentaires ou non alimentaires. Les récipients alimentaires sont utilisés dans les conditions bien réglementées par divers pays développées, afin de s'assurer qu'ils ne libèrent pas les polluants dans les aliments. En Afrique et au Cameroun en particulier, cette réglementation n'existe pas. De plus, c'est une zone de grande contrebande, et l'usage de récipients non alimentaires dans la préservation des aliments est pratiqué. Les plastiques sont constitués de longues chaînes polycarbonées appelées polymères dont les bonnes propriétés mécaniques, électriques et thermiques proviennent de l'ajout des additifs lors de leur formulation. Parmi ces additifs, les bisphénols et les phtalates sont utilisés respectivement comme des antioxydants et plastifiants. Ces molécules ont été reconnues comme dangereuses pour la santé humaine du fait qu'elles sont des perturbateurs endocriniens et sont impliquées dans de nombreux cancers. La principale voie d'entrée de ces molécules dans l'Homme est alimentaire. Leur migration des récipients plastiques vers les aliments est facilitée par les conditions de conservation, les modes de traitement et la nature de ces derniers. L'objectif du présent travail est d'étudier le transfert des bisphénols et phtalates des récipients plastiques vers les matrices alimentaires. Il était question de dégager les risques de contamination humaine par les récipients plastiques au travers d'une enquête auprès des ménages et des industries. Puis, l'évaluation de l'exposition de la population passait par la mise au point des méthodes de chromatographie liquide couplée au spectromètre de masse pour quantifier ces molécules dans les matrices alimentaires. Enfin, l'étude du transfert des phtalates des seaux de peinture vers les aliments était effectuée via les plans d'expériences et l'étude cinétique. Ce travail a montré que 36,5% des ménages utilisaient des anciens seaux de peintures dans l'alimentation, et cette utilisation ne dépend pas de la classe sociale. Les méthodes par dérivatisation suivi de l'analyse en chromatographie liquide se sont avérées très fiables, sensibles et rapides pour la quantification des bisphénols (A, B et F) et des phtalates totaux dans les aliments. Le calcul des doses journalières ingérées a montré que l'exposition à ces composés reste faible via l'alimentation. L'étude cinétique a révélé que la migration des phtalates est mieux décrite par le modèle de pseudo-second ordre et dépend principalement de la température, du temps de contact, et le pH. Ces paramètres présentent tous des interactions non négligeablesPlastic containers are either food or non-food grade. The food grade containers are used under the well-regulated conditions by various developed countries, to ensure that the pollutants cannot diffuse into food. In Africa and Cameroon in particular, this regulation does not exist. In addition, it is an area of great smuggling, and the use of non-food grade containers in the preservation of food is practiced. Plastics are made up of long polycarbon chains called polymers whose good mechanical, electrical and thermal properties come from the addition of additives during their formulation. Among these additives, bisphenols and phthalates are used respectively as antioxidants and plasticizers. These molecules have been recognized as dangerous for human health because they are endocrine disruptors and are involved in many cancers. The main route of entry of these molecules into humans is food. Their migration from plastic containers to food is facilitated by storage conditions, processing methods and the nature of food. The objective of this work is to study the transfer of bisphenols and phthalates from plastic containers to food matrices. It was a question of identifying the risks of human contamination by plastic containers through a survey of households and industries. Then, the evaluation of the exposure of the population went through the development of a method based on liquid chromatography-tandem mass spectrometry to quantify these molecules in food matrices. Finally, the study of the transfer of phthalates from paint buckets to food was carried out via experimental design and the kinetic study. This work showed that 36.5% of households used old paint buckets in food, and this use did not depend on social class. Derivatization methods followed by liquid chromatography analysis have proven to be precise and rapid for the quantification of bisphenols (A, B and F) and total phthalates in foods. The estimated dietary daily intake of bisphenols and phthalates through foods remains low in Cameroon. The kinetic study revealed that the migration of phthalates is best described by the pseudo-second-order model and depends mainly on temperature, contact time, and pH. These parameters present significant interactions
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Adawi, Rahim. "Preventing fatal effects of overworking : Product design solution". Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-15473.
Testo completoAbstract (sommario):
“Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn."Guolaosi" eller död från överarbete är ett fenomen som i regel uppkommer bland utvecklingsländer. Dödsorsaken är huvudsakligen genom stroke. Offrens yrken varierar allt från professorer, IT-arbetare till läkare. De delar dock en sak gemensamt; att arbeta under långa perioder stillasittande. Projektets mål var att utveckla en produkt som minskar dödliga följderna av sedentära överarbete, genom att förebygga en av de tre orsakerna för att utveckla blodproppar; saktad blodström. Målgruppen var då kineser av de yrken som hade tidigare drabbats av fenomenet. För att samla informationsrika data om fenomenet genomfördes en kvalitativ studie i Kina under två månader. Genom att göra en omfattande strukturerad provtagning kunde informationsrika data samlas under en kort tidsperiod. Fältstudien bestod av observationer, frågeformulär och en intervju, som då tolkades till kundbehov och eventuellt produktspecifikationen. Den slutliga produkten kom att bli ett par byxor med en inbyggd dynamisk komprimeringsmekanism, som kan komprimera venerna under sittande aktiviteter, för att förhindra saktad blodström. Kompressionsmekanismen fungerar som den kinesiska fingerfällan. Den komprimerar blodkärlen medan personen sitter och sträcker benen framåt. Produkten är konstruerad på så sätt att den kan tillverkas endast av polysackariders tråd, från bomull och majs. Vilket är lämpligt för Kinas lokala resurser.
Libri sul tema "Plastics – Toxicology"
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Corporation, Radian, a cura di. Plastics processing: Technology and health effects. Park Ridge, N.J., U.S.A: Noyes Data Corp., 1986.
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Sheftel, Victor O. Handbook of toxic properties of monomers and additives. Boca Raton: Lewis Publishers, 1995.
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Tolinski, Michael. Plastics and sustainability: Towards a peaceful coexistence between bio-based and fossil fuel-based plastics. Hoboken, N.J: John Wiley & Sons, 2012.
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Cheremisinoff, Nicholas P. Handbook of hazardous and toxic properties of polymer chemicals. Englewood Cliffs, N.J: PTR Prentice Hall, 1994.
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Zimmerman, Roy. Plastics in medicine, science & law: Subject analysis index with reference bibliography. Washington, D.C: ABBE Publishers Association, 1987.
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N, Moye Gail, a cura di. Phthalates and bisphenol-A in plastics and possible human health effects. New York: Nova Science Publishers, inc., 2009.
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N, Moye Gail, a cura di. Phthalates and bisphenol-A in plastics and possible human health effects. New York: Nova Science Publishers, inc., 2009.
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1946-, Gmehling Jürgen, a cura di. Stoffbelastungen bei der Kunststoffverarbeitung. Dortmund: Bundesanstalt für Arbeitsschutz, 1993.
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Nakazawa, Hiroyuki. Kōbunshi sozai kara naru seikatsu kanren seihin yurai no naibunpitsu kakuran kagaku busshitsu no bunseki oyobi dōtai kaiseki (H11, seikatsu, 023): Heisei 12-nendo kōsei kagaku kenkyūhi hojokin (seikatsu anzen sōgō kenkyū jigyō) kenkyū seika hōkokusho. Japan: s.n., 2001.
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Nakazawa, Hiroyuki. Kōbunshi sozai kara naru seikatsu kanren seihin yurai no naibunpitsu kakuran kagaku busshitsu no bunseki oyobi dōtai kaiseki (H11, seikatsu, 023): Heisei 11-nendo kōsei kagaku kenkyūhi hojokin (seikatsu anzen sōgō kenkyū jigyō) kenkyū seika hōkokusho. Japan: s.n., 2000.
Cerca il testo completoCapitoli di libri sul tema "Plastics – Toxicology"
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Pauluhn, Jürgen. "Combustion Toxicology". In Plastics Flammability Handbook, 219–46. 4a ed. München: Carl Hanser Verlag GmbH & Co. KG, 2021. http://dx.doi.org/10.3139/9781569907634.007.
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Pauluhn, Jürgen. "Combustion Toxicology". In Plastics Flammability Handbook, 219–46. München, Germany: Carl Hanser Verlag GmbH & Co. KG, 2021. http://dx.doi.org/10.1007/978-1-56990-763-4_7.
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Banasik, Marek. "Plastics". In Hamilton & Hardy's Industrial Toxicology, 759–84. Hoboken, New Jersey: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781118834015.ch75.
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Etzrodt, Günter. "Chemical Safety, CLP Regulation, Toxicology". In Industrial Coloration of Plastics, 393–404. München: Carl Hanser Verlag GmbH & Co. KG, 2022. http://dx.doi.org/10.3139/9781569908532.016.
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Etzrodt, Günter. "Chemical Safety, CLP Regulation, Toxicology". In Industrial Coloration of Plastics, 393–404. München, Germany: Carl Hanser Verlag GmbH & Co. KG, 2022. http://dx.doi.org/10.1007/978-1-56990-853-2_16.
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Snedeker, Suzanne M. "Antimony in Food Contact Materials and Household Plastics: Uses, Exposure, and Health Risk Considerations". In Molecular and Integrative Toxicology, 205–30. London: Springer London, 2014. http://dx.doi.org/10.1007/978-1-4471-6500-2_8.
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Hammer, Jort, Michiel H. S. Kraak e John R. Parsons. "Plastics in the Marine Environment: The Dark Side of a Modern Gift". In Reviews of Environmental Contamination and Toxicology, 1–44. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-3414-6_1.
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Vighi, Marco, Javier Bayo, Francisca Fernández-Piñas, Jesús Gago, May Gómez, Javier Hernández-Borges, Alicia Herrera et al. "Micro and Nano-Plastics in the Environment: Research Priorities for the Near Future". In Reviews of Environmental Contamination and Toxicology Volume 257, 163–218. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/398_2021_69.
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Hankermeyer, Christine R., e Ronald S. Tjeerdema. "Polyhydroxybutyrate: Plastic Made and Degraded by Microorganisms". In Reviews of Environmental Contamination and Toxicology, 1–24. New York, NY: Springer New York, 1999. http://dx.doi.org/10.1007/978-1-4612-1496-0_1.
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Liu, Liang-Ying, Lei Mai e Eddy Y. Zeng. "Plastic and Microplastic Pollution: From Ocean Smog to Planetary Boundary Threats". In A New Paradigm for Environmental Chemistry and Toxicology, 229–40. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9447-8_14.
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