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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Microplastics in Scanian wetlands : Sege river & Kävlinge river / Mikroplaster i Skånska våtmarker : Sege å & Kävlingeån

Stoltz, Ludvig, Leijon, Pernilla January 2023 (has links)
It is estimated that 75 million tons of plastics waste is currently in the ocean and expects to increase in line with plastic consumption. Plastic items in natural or aquatic environments are fragmented into smaller pieces called microplastics. Microplastics can enter rivers and lakes through sewage water to end up in wetlands where they sediment. Due to lack of standard monitoring tools, microplastics in a Scanian context are rather uninvestigated. The current work therefore studies microplastics’ abundance in eleven wetlands along the Sege river and Kävlinge river. The aim is with available methods and tools to examine microplastics in sediment and examine if determined microplastics concentrations can relate to urbanization in the two catchments. The study also looked into wetlands position in relation to stream order to test if microplastics concentrations increase downstream. In the study, density separation has been used to extract microplastics from soil samples and analyzed using correlation. The result showed microplastics concentrations in all sampling sites. There was weak negative or no correlation with degree of urbanization nor a relation to higher concentration further downstream along Sege river and Kävlinge river. However, the study concludes that microplastics do appear in Scanian wetlands and not necessarily in the vicinity of human activity which complies with microplastics' ability to travel long distances. / Idag finns det cirka 75 miljoner ton plastavfall i haven, som förväntas öka i samband med ökad plastkonsumtion. Plastföremål i naturliga eller akvatiska miljöer fragmenteras till mindre bitar som kallas mikroplast. Mikroplast kan transporteras till åar och sjöar genom dagvatten eller avloppsvatten, och slutligen sedimenteras i våtmarker. Inom arbete med plastföroreningar i Skåne saknas övervakning av mikroplast koncentrationen. På grund av brist på standardverktyg för övervakning är mikroplaster i Skåne förhållandevis outforskat. Denna studie tittar därmed på mikroplast förekomsten i elva våtmarker längs Sege å och Kävlingeån. Syftet är att med tillgängliga metoder och verktyg undersöka mikroplast i sediment, om koncentrationer kan relatera till tätorter i närområdet. Studien tittar också på våtmarkernas position i förhållande till stream order för att testa om mikroplast koncentrationerna ökar nedströms. I studien har flotteringsmetoden använts för att extrahera mikroplaster från jordprover och dessa analyserades med korrelation. Resultatet visade på förekomst av mikroplaster i samtliga våtmarker. Dock kunde studien inte påvisa någon relation mellan urbanisering och högre koncentration av mikroplaster och resultaten visade också en svag negativ eller ingen korrelation mellan en ökad koncentration av mikroplaster och stream order. Vad studien kan dra för slutsatsen är att mikroplaster förekommer i skånska våtmarker som inte nödvändigtvis är i närheten av mänsklig aktivitet vilket överensstämmer med mikroplasters förmåga att färdas långa sträckor.
52

Environmental Fate of Fibrous Microplastics of Textile origin: – Insights into the Retention in a lab-scale Wastewater Treatment Plant and Biodegradation Evaluation

Lykaki, Marianna 01 November 2022 (has links)
Mikroplastik (MPs) Partikel die kleiner als 5 mm sind, werden weltweit als neu identifizierte Gefahr auf die Umwelt betrachtet. Um geeignete Minderungsstrategien entwickeln zu können, werden diese neuartigen Umweltschadstoff hinsichtlich möglicher Eintragsquellen und potentieller Transportwege in der Umwelt zunehmend diskutiert. Gründe für eine notwendige Reduzierung von MPs in der Umwelt gibt es viele. Es werden dabei insbesondere das Transportverhalten in der Umwelt sowie deren Toxizität auf das System Mensch und Umwelt als Schlüsselkomponenten angesehen. Die in den letzten zehn Jahren gestiegene Nachfrage an synthetischen Textilien und der daraus resultierenden Produktionssteigerung hat zur Folge, dass diese Textilien eine Hauptquelle der MP-Verschmutzung im aquatischen System darstellen. Jedoch fehlen aktuell spezifische Informationen über die Größe und den Verbleib von faserigen Mikroplastikpartikeln (FMP), die aus gewaschenen Textilien des täglichen Lebens freigesetzt werden, wenn sie die Kläranlagen passieren und schließlich in Ökosysteme gelangen. Ziel dieser Arbeit ist es, die prävalent vorkommenden Größenfraktionen aus Polyethylenterephthalat (PET) FMPs, die aus synthetischen Fleecejacken beim Waschen in einer kommerziellen Waschmaschine freigesetzt werden, zu identifizieren und anschließend zu quantifizieren. Dabei soll ihr Vorkommen und ihr Verbleib in konventionellen Kläranlagen unter Berücksichtigung verschiedener Behandlungsstufen untersucht werden. Um den potenziellen Einfluss der PET-Faserlänge auf das Transportverhalten in Kläranlagen zu untersuchen, wurden zwei unterschiedlichen Größenfraktionen (1500 – 500 µm und 150 – 50 µm) in Batchtests miteinander verglichen. Darüber hinaus wurde in dieser Studie die Wirksamkeit der Koagulation, einem etablierten Verfahren aus der chemischen Abwasserbehandlung, auf die Eliminierung von FMP-PET-Fasern aus Abwässern untersucht. Unter Verwendung eines aus einer städtischen Kläranlage stammenden Inokulums wurde die biologische Abbaubarkeit von FMPs (PET) im Labormaßstab im Vergleich zu natürlichen (Baumwolle), regenerierten (Viskose), PET/Baumwoll-Mischgewebe und oxo-abbaubaren PET-Fasern untersucht. Zusätzlich wurde der Einfluss verschiedener Ausrüstungsverfahren (z.B. Reaktivfarbstoffe, Weichmacher und antimikrobielle Zusätze) auf die biologische Abbaubarkeit von Viskosefasern getestet. Der Waschtest ergab, dass die höchste Freisetzung von FMPs beim ersten Waschen auftrat und mit einer schrittweisen Reduzierung der Faseremission in weiteren Versuchen einherging. Bei einer Gesamtverteilung der PET-Faserlänge zwischen >1500 - 5 µm deckte die am häufigsten vorkommende massenbezogene Größenfraktion einen Bereich von 500 µm bis 50 µm ab. In einer Kläranlage konnte festgestellt werden, dass die Mehrheit der PET-Fasern unabhängig von der Größenverteilung mit partikulären Feststoffen abgeschieden werden (>90 % für Belebtschlamm und >99 % für Primärschlamm). Es konnte jedoch beobachtet werden, dass ein erhöhter Anteil kleiner Fasern (150 – 50 μm) in der flüssigen Phase verbleiben, was darauf hindeutet, dass kleineren Fasern nicht durch Kläranlagen zurückgehalten werden und schließlich in die Gewässer gelangen. Darüber hinaus konnte gezeigt werden, dass die Zugabe einer Koagulationschemikalie die Entfernung von großen PET Fasern (1500 – 500 μm) aus Abwässern geringfügig verbessern könnte; der Effekt war jedoch nicht signifikant. Die biologische Abbaubarkeit von Fasern in aquatischen Matrices nahm mit folgender Reihenfolge ab: Baumwolle ≥ Viskose > PET/Baumwollmischung > oxo-abbaubares PET ≥ PET. Dabei wiesen mit bestimmten Ausrüstungsmitteln behandelte Fasern im Vergleich zu unbehandelten Fasern einen niedrigeren Mineralisierungsgrad auf. Dieses zentrale Ergebnis unterstreicht die Bedeutung zur Berücksichtigung der Textilausrüstung bei der Bewertung des Umweltverhaltens von FMP. Dies ist die erste Studie, in der sich in der Abwasserbehandlung ausschließlich auf das Verhalten von PET-Fasern als eins der am häufigsten verwendeten Materialien in der Bekleidungsindustrie konzentriert wurde. Es konnte gezeigt werden, dass das Verhalten von textilbasierten FMPs bei der Abwasserbehandlung größenabhängig sein kann. Darüber hinaus wurde beobachtet, dass die Textilveredelung, je nach Haltbarkeit und Art des verwendeten Additivs, die Halbwertszeit von Faserschuppen in der Umwelt verlängern kann. Beide Erkenntnisse sind von großer Bedeutung, um nachhaltige Textilprodukte mit einer deutlich geringeren FMP-Emission in die Umwelt und im Hinblick auf eine funktionierende Kreislaufwirtschaft zu entwerfen. / Microplastics (MPs), plastic particles <5 mm, have been considered as global emerging environmental contaminants, triggering discussions regarding their sources, transport pathways and possible mitigation strategies, while fate and toxicity are recognized as key issues, including their potential threats to human health. The increased production and use of synthetic clothes over the last decade have placed synthetic textiles as one of the main sources of MP pollution in aquatic environments. However, there is still lack of information specifically on the size and fate of Fibrous Microplastic Particles (FMPs) released from washed daily-life products when they pass through Wastewater Treatment Plants (WWTPs) and eventually end up in the ecosystems. This thesis aims to investigate the amount and the dominant size fractions of polyethylene terephthalate (PET) FMPs released from synthetic fleece jackets during washing and to understand their occurrence and fate in conventional WWTPs, by considering different treatment stages. The potential influence of fibre length on the removal of PET fibres in WWTP was also investigated in batch tests, with two size fractions being compared, i.e. 1500 – 500 μm and 150 – 50 μm. Additionally, this study examined the efficacy of the coagulation, an established process of chemical treatment, on the elimination of FMP PET fibres from wastewaters. Finally, the present study evaluated the biodegradability of FMPs (PET) compared to natural (cotton), regenerated (viscose), PET/cotton blend and oxo-degradable PET fibres under laboratory conditions, by using inoculum from a WWTP, as well as the influence of different finishing processes (i.e. reactive dyes, softener and antimicrobial agent) on the biodegradability of viscose fibres. The washing test revealed that the highest release of PET fibres occurred in the first wash, with a consequent reduction of fibres’ emissions in sequential trials. PET fibre sheds collected with the aid of a filter cascade ranged from >1500 – 5 μm, with the most dominant size fraction in terms of mass ranging from 500 μm to 50 μm. Microscopic and gravimetric analysis revealed that when present in a WWTP, the majority of PET fibres were found to be associated to solids (>90% for activated and >99% for primary sludge), irrespective of their size fraction. However, small fibres (150 – 50 μm) were demonstrated to be retained in the liquid phase to a higher extent, indicating the likelihood of smaller fibres to pass through the WWTPs, entering eventually the water bodies. Moreover, our results showed that the addition of the coagulant chemical could slightly enhance the removal of large PET fibres (1500 – 500 μm) from wastewater effluents; however the effect was not significant. The biodegradability of fibres in aquatic environments decreased with the following order: cotton ≥ viscose > PET/cotton blend > “oxo-degradable” PET ≥ PET, while fibres treated with certain finishing agents displayed a lower mineralization level compared to the untreated, highlighting the importance of considering the textile finish when assessing the environmental behavior of FMPs. This is the first study giving emphasis solely on the behavior of PET fibres, one of the most common materials used in apparel industry, demonstrating that the performance of FMPs originated from textiles in wastewater treatments may be size-dependent. Moreover, it was shown that textile finishing might prolong the environmental half-lives of fibre sheds, depending on the durability and type of additive applied. Both findings are important when aiming at designing sustainable textile products with respect to a circular economy and considerably less FMPs emissions in the environment.
53

Investigating the Quantity and Types of Microplastics in the Organic Tissue of Oysters and Crabs in the Indian River Lagoon

Waite, Heidi 01 January 2017 (has links)
Microplastics are widespread and abundant. Few studies have examined the diversity and abundance of microplastics in wild organisms. This study determined the microplastic quantity and types in the organic tissues of the eastern oyster Crassostrea virginica and Atlantic mud crab Panopeus herbstii from the Indian River Lagoon (IRL). This study also investigated whether location affected the microplastic abundance and variety. Organisms were collected from three sites across Mosquito Lagoon in the northern IRL. Oysters were frozen after collection. Crabs were placed in containers for 5 days before freezing. The soft organic tissue was chemically digested using hydrogen peroxide, filtered, and examined for microplastics. Water samples collected from each study site had an average of 23.1 microplastic pieces per liter and fibers were the most common type. There was a significant interaction for microplastic type and site for both oysters and crabs (p
54

Investigation of Microplastic Accumulation in the Gastrointestinal Tract in Birds of Prey

Carlin, Julia 01 January 2019 (has links)
Plastic pollution is unavoidable in the natural environment. Consequences of plastic ingestion include exposure to environmental pollutants and toxin accumulation, causing endocrine disruption, inflammatory and physiological stress in organisms. Microplastics have been shown to transfer across food webs, however, limited studies have examined microplastic accumulation across terrestrial food webs. Furthermore, few studies have examined plastic pollution in apex predatory animals. A study was conducted to quantify the abundance of plastic pollution in the gastrointestinal tract in birds of prey. Two species were investigated, one which forages in terrestrial habitats and one which forages in aquatic environments including Buteo lineatus (red-shouldered hawk) and Pandion haliaetus (osprey), respectively. The gastrointestinal tract was necropsied, chemically digested, and examined for microplastic prevalence. Overall, microplastics are significantly more abundant per gram of gastrointestinal (GI) tract tissue in species that forage on small rodents and terrestrial reptiles (B. lineatus) as compared to species that forage on fish and aquatic invertebrates (P. haliaetus). Buteo lineatus averaged 0.81 (±0.15) fibers and 0.14 (±0.04) fragments per gram of GI tract tissue while P. halieatus averaged 0.31 (±0.09) fibers and 0.04 (±0.02) fragments per gram of GI tract tissue. There was a significant interaction between type and color in both B. lineatus and P. haliaetus GI tract tissues. Micro-Fourier-transform infrared spectroscopy (μ-FTIR) was run on haphazardly selected samples and found that rayon was the most common polymer identified in both species. The significant difference found between species could be indicative that terrestrial raptors may experience greater bioaccumulation than aquatic species foraging at comparable trophic levels. However, the significant interaction between type and color in both species indicates a potential common source of pollution that affects both environments. Further investigation on the source of polymers is necessary in order to develop conservation and management strategies aimed at decreasing the output of synthetic fibers into the environment. Due to the abundance of polymers found in these species, understanding the potential biological and physiological effects of plastics is essential to informing superior management strategies that can better protect and preserve wildlife from increasing anthropogenic pressures.
55

Limiting microplastic pollution from municipal wastewater treatment : A circular economic approach / Begränsning av mikroplastföroreningar från kommunal avloppsrening : En cirkulär ekonomisk strategi

van Osch, Jordy January 2020 (has links)
The increasing amount of microplastics found in the environment have underscored the urgency to identify, develop and deploy scenarios in which municipal wastewater treatment plants (MWWTPs) limit the release of urban microplastics into the environment. Simultaneously, the global trend towards a circular economy has defined the conditions for these scenarios in relation to the water-energy- nutrient nexus. This study has created a novel framework between studies into treatment technologies for microplastics removal in wastewater streams and circular economic objectives from policymakers with regard to the water-energy-nutrient nexus. The results of this study build on the existing evidence that MWWTPs release significant amounts of microplastics to both terrestrial and aquatic environments. This study has demonstrated how Multi-criteria Analysis (MCA) can be applied to analyse wastewater treatment scenarios for their ability to limit microplastic pollution from MWWTPs, whilst taking the water-energy- nutrient nexus into account. The MCA has identified MBR inci-eco as the best performing circular economic scenario for limiting microplastic pollution from MWWTPs in to be constructed plants. This scenario includes a Membrane Bioreactor (MBR) with Anaerobic Digestion, energy recovery through incineration and Phosphorus recovery through Ecophos. If already existing MWWTPs aim to upgrade their facility to limit microplastic pollution, CASPACUF with Pyreg as an energy-nutrient recovery is seen as the best performing scenario. The powder activated carbon with ultra filtration (PAC-UF) system would then be installed as an additional polishing step to an existing conventional activated sludge (CAS) system, significantly reducing upfront investment costs. Academia can build upon these results to initiate additional research into novel microplastic filtration specific technologies, business model innovation for wastewater treatment and microplastic pollution prevention at the source and in stormwaters. National and international policymakers should ban the distribution and sale of biosolids for direct land application to limit the pollution of microplastics from bio-solids. Furthermore, efforts should be put in place to limit microplastic pollution at the source by stimulating policies for a ban on the use of microbeads, limit tyre wear and improving design for e.q. washing machines. / Den ökande mängden mikroplast som finns i miljön har understrukit brådskan i att identifiera, utveckla och tillämpa strategier där kommunala avloppsreningsverk (MWWTP) begränsar utsläpp av urbana mikroplaster. Samtidigt har den globala trenden mot en cirkulär ekonomi definierat villkoren för dessa scenarier i förhållande till vatten-energi-näring-näxan. Denna studie har tagit fram ett nytt ramverk mellan studier om reningsteknologier för avlägsnande av mikroplast i avloppsvattenströmmar och cirkulära ekonomiska mål från beslutsfattare med avseende på water-energy-nutrient nexus. Resultaten av denna studie bygger på befintliga bevis på att kommunala avloppsreningsverk släpper ut betydande mängder mikroplast i både mark- och vattenmiljöer. Denna studie har visat hur Multi-Criteria Analysis (MCA) kan användas för att analysera avloppsreningsscenarier utifrån deras förmåga att begränsa mikroplastföroreningar från reningsverk, samtidigt som man tar hänsyn till vatten-energi-näring-näxan. MCA har identifierat MBR-inci-eco som det bäst presterande cirkulära ekonomiska scenariot för att begränsa mikroplastföroreningar från nya verk. Detta scenario inkluderar en Membrane Bioreactor (MBR) med anaerobisk nebrytning, energiåtervinning genom förbränning och fosforåtervinning genom Ecophos. Om redan befintliga verk ska uppgradera sin anläggning för att begränsa mikroplastföroreningar, ses CASPACUF med Pyreg som energi-näringsåtervinning som det bästa scenariot. Det pulveraktiverade kolet med ultrafiltreringssystemet (PAC-UF) skulle sedan installeras som ett ytterligare poleringssteg till ett befintligt konventionellt system för aktiverat slam (CAS), vilket avsevärt minskar investeringskostnaderna. Framtida forskning kan använda dessa resultat för att undersöka nya mikroplastfiltreringsspecifika tekniker, affärsmodellinnovation för avloppsrening och förebyggande av mikroplastförorening vid källan och i stormvatten. Nationella och internationella beslutsfattare bör förbjuda distribution och försäljning av biosolids för direkt markanvändning för att begränsa mikroplastföroreningar från biosolids. Vidare bör åtgärder vidtas för att begränsa mikroplastföroreningar vid källan genom att stimulera policyer för ett förbud mot användning av mikrokulor, begränsa däckslitage och förbättra designen för e.q. tvättmaskiner.
56

Outils alternatifs à l'expérimentation animale pour l'évaluation de la toxicité des contaminants de l'environnement : lignées cellulaires et tests embryo-larvaires chez un poisson modèle le Médaka japonais, Oryzias latipes / Alternative tools to animal testing for toxicity assessment of environmental contaminants : cell lines and embryo-larval assay in model fish Japanese Medaka, Oryzias latipes

Pannetier, Pauline 11 April 2018 (has links)
Les poissons sont parmi les modèles aquatiques les plus utilisés pour l’évaluationdes dangers des substances chimiques avant leur mise sur le marché européen(REACh (Registration, Evaluation, Autorisation and Restriction of CHemicals)).Actuellement, cette réglementation ainsi que la directive européenne sur la protectiondes animaux utilisés à des fins scientifiques (2010/63/UE) promeuvent la mise enplace de méthodes alternatives en expérimentation animale. Ces méthodes ont pourbut de remplacer les modèles animaux chaque fois que cela est possible, de réduirele nombre d’animaux utilisés en expérimentation et d’optimiser la méthodologieappliquée aux animaux. Cette thèse vise à comparer la sensibilité de deux de cesoutils alternatifs, les lignées cellulaires et les tests embryo-larvaires poissons, enutilisant des toxiques modèles puis mettre en oeuvre ces outils pour évaluer la toxicitéde mélanges environnementaux de polluants : microplastiques et hydrocarbures(pétrole Arabian Light). Les composés modèles (B(a)P, Cd, MMS, PCB126) ont permisde valider trois biomarqueurs : la production d’espèces réactives de l’oxygène surlignées cellulaires de poissons, le test micronoyaux par cytométrie en flux et lechallenge infectieux sur larves de Médaka. Ces biomarqueurs associés à des analyseschimiques, biochimiques et physiologiques ont permis d’évaluer la toxicité demélanges environnementaux d’hydrocarbures (extrait aqueux de pétrole Arabian =WAF) et de microplastiques. Les WAF présentent une toxicité sur les lignéescellulaires de poissons (induction de l’activité EROD, génotoxicité) ainsi que surembryons et larves de Médaka (comportement, biométrie, EROD, génotoxicité). Lespoissons comme les cellules sont particulièrement sensibles au WAF de l’ArabianLight. La contamination aux microplastiques (MP) environnementaux a révélé unetoxicité des contaminants associés au MP sur les lignées cellulaires et les larves depoisson. L’ingestion de particules de plastiques par les larves a induit des effets létauxet sublétaux (biométrie, comportement et EROD). L’ingestion des particules plastiquespar les larves a été confirmée par microscopie biphotonique. Cette étude a permisd’évaluer la sensibilité et la complémentarité de ces outils in vitro pour l’évaluation desdangers et des risques associés aux substances chimiques. / Fish are among the most widely used aquatic model for assessing the chemicalthreat before they are placed on the European market (REACh (Registration,Evaluation, Authorization and Restriction of CHemicals)). Currently, this regulation aswell as the European directive on the protection of animals used for scientific purposes(2010/63/EU) promote the establishment of alternative methods in animal testing.These methods are intended to replace animal models whenever possible, to reducethe number of animals used in experiments and to optimize the methodology appliedto animals. This thesis aims to compare the sensitivity of two of these alternative tools,cell lines and fish embryo-larval tests, using model toxicants. Then, these tools wereused to evaluate the toxicity of environmental mixtures of pollutants: microplastics andhydrocarbons (Arabian Light oil). The model compounds (B(a)P, Cd, MMS, PCB126)valid three biomarkers: reactive oxygen species (ROS) production on fish cell lines,micronucleus assay by flow cytometry and infectious challenge on Medaka larvae andjuveniles. These biomarkers combined with chemical, biochemical and physiologicalanalyzes have assessed toxicity of environmental mixtures of hydrocarbons (aqueousextract of Arabian oil = WAF) and microplastics. WAF are toxic to fish cell lines (ERODactivity induction and genotoxicity) as well as to Medaka embryos and larvae (behavior,biometrics, EROD, genotoxicity). Fish like cells seem to be particularly susceptible toArabian Light WAF. Contamination with environmental microplastics (MP) hasrevealed a toxicity of MP-associated contaminants on cell lines and fish larvae. Theingestion of plastic particles by the larvae induced lethal and sublethal effects(biometrics, behavior and EROD). The ingestion of the plastic particles by the larvaewas confirmed by two-photon microscopy. This study assessed the sensitivity andcomplementarity of these in vitro tools for assessing hazards and risks associated withchemicals.
57

Les microplastiques et leurs additifs dans les produits de la pêche : développements méthodologiques et prévalence / Microplastics and their additives in seafood products : methodological developments and prevalence

Hermabessiere, Ludovic 12 November 2018 (has links)
L'augmentation de la production de matière plastique depuis les années 1950 combinée à une mauvaise gestion des déchets plastiques ainsi qu'aux mauvais comportements des citoyens conduit à la contamination des écosystèmes terrestres comme marins. L'ingestion par des organismes marins de particules plastiques mesurant moins de 5 mm, appelées microplastiques, a été décrite. L'objectif de ces travaux de thèse était d'évaluer le danger "microplastique" pour le consommateur de produits de la pêche. Afin de répondre à cet objectif, la sélection et la caractérisation d'une méthode permettant de digérer les tissus des produits de la pêche a été. En parallèle, une méthode de Pyrolyse-GC/MS a été optimisée afin d'identifier les microplastiques les plus petits possibles. Ses limites d'applications ont été calculées puis la méthode a été appliquée sur des microplastiques provenant de différents produits de la pêche. Ces deux méthodes ont été appliquées dans la recherche de microplastiques dans deux espèces de bivalves et trois espèces de poissons. Pour les bivalves, la contamination aux microplastiques était comprise entre 0.15 et 0.74 MP/g de chair humide alors que pour les poissons la contamination était assez faible : 0,01 MP/g de tractus gastro-intestinal et 0,001 MP/g de filet. Pour finir, une étude exploratoire de la lixiviation d'un additif plastique en utilisant un modèle de digestion in vitro a été entreprise. Globalement, ces travaux de thèse permettent de proposer des voies d'harmonisation des méthodes pour l'étude des microplastiques dans les produits de la pêche pour, in fine, évaluer le danger pour le consommateur. / Increase in plastic production since the 1950's in combination with plastic waste mismanagement lead to the presence of plastic particle in terrestrial and marine environment. Plastic particles measuring less than 5 mm, called microplastics, are ingested by a wide range of organisms. The goal of this PhD thesis was to evaluate the microplastic hazard for seafood consumers. firstly, method for digesting seafood tissue without degrading plastic polymer was selected and applications limits were determined for digestion of fish digestive tracts. Concurrently, a Pyrolysis-GC/MS method was optimized, limit of detection were determined and this method was applied on environmental samples. Both methods were used to study microplastics contamination in bivalve and fish species used for human consumption. Bivalve contamination was between 0.15 and 0.74 MP/g of tissue wet weight whereas contaminations in fish were low. Indeed, digestive tracts were contaminated by in mean 0.01 MP/g of tissue wet weight and muscles were contaminated by in mean 0.001 MP/g of tissue wet weight. Lately, leaching of a plastic additive was studied using an in vitro enzymatic model of digestion. However, such phenomenon was not highlighted. Overall, these results will help to standardize the study of microplastics in seafood products.
58

Estudo da distribuição de metais em plásticos no litoral de São Paulo: avaliação da poluição por meio de análise de pellets / Study of the distribution of metals in plastics at São Paulo coast: an avaliation of pollution with analysis of plastic pellets

Vedolin, Marcela Corrêa 17 March 2014 (has links)
A matéria prima das indústrias transformadoras de utensílios plásticos são os pellets de plástico, que recebem quantidades significativas de aditivos os quais possuem metais pesados e elementos tóxicos. Devido à perda desses pellets durante os processos de produção e transporte, tais contaminantes são liberados no ambiente. Este estudo investiga as interações entre os metais dissolvidos em pellets coletados em diferentes praias do litoral de São Paulo. Especificamente, o estudo comparou a realização do método em grânulos virgens, ou seja, aqueles obtidos a partir de uma fábrica de moldagem com os recolhidos das praias. Foram quantificados os elementos: Al, Cr, Cu, Fe, Mn, Sn, Ti e Zn empregando a técnica de espectrometria de emissão atômica com plasma indutivamente acoplado (ICP-OES). Os polímeros foram solubilizados via digestão ácida (EPA3050B). As concentrações dos metais exibiram um elevado grau de variabilidade, sendo Al e Fe os elementos de maiores concentrações 58,63 mg kg-1, praia de Tabatinga e 391,56 mg kg-1, praia de Itaguaré, respectivamente. Diferenças de afinidades entre os metais para os pellets coletados no ambiente e aqueles obtidos diretamente a partir de uma processadora de plásticos (virgem) também foram identificados. A adsorção de metais em pellets coletados é maior em relação aos pellets virgens, isso ocorre devido ao desenvolvimento de sítios de adsorção na superfície para realização de foto-oxidação, incrustação e deposição de sedimentos finos e/ou partículas durante a exposição a condições ambientais. Este estudo demonstrou que pellets de plástico têm o potencial acumular e transportar metais no ambiente marinho, mesmo em pequena quantidade. Eles podem ser considerados como um vetor para o transporte de metais no meio ambiente, e podem ter o potencial de acumular metais em organismos após a ingestão. / The raw material of plastic industries is plastic pellets, which receive significant amounts of additives which contain heavy metals and toxic elements. Due to the loss of these pellets during the processes of production and transportation, such contaminants are released into the environment. This study investigates the interactions between metals dissolved in pellets collected in different beaches of the coast of São Paulo state. Specifically, the study compared the performance of the method in virgin granules, ie, those obtained from a molding factory with those collected from the beaches. The following elements quantified: Al , Cr , Cu , Fe , Mn , Sn , Ti and Zn in samples of virgin pellets supplied by Braskem, manufacturer of resins, employing the technique of Inductively coupled plasma atomic emission spectroscopy ( ICP - OES .) The polymers were solubilized via acid digestion (EPA3050B). The metal concentrations exhibited a high degree of variability being Al and Fe elements with higher concentrations: 58.63 mg kg-1 at Tabatinga beach and Fe 391.56 mg kg-1, at Itaguaré beach. Affinity differences between metals for pellets collected in the environment and those obtained directly from a processor of plastics (virgin) were also identified. The maximum adsorption for virgin pellets ranged between 14.09 mg kg-1 (polyethylene, used as control) to 58.63 mg kg-1 for Al. However, for the other elements except Fe, the concentrations were below the limit of quantification. The metal adsorption on pellets collected is greater compared to virgin pellets. This is due to the development of viable local surface for performing photo-oxidation, scaling and deposition of fine sediments and/or particles during exposure to environmental conditions. This study demonstrated for the first time, that the plastic pellets have the potential to accumulate metals and transporting the marine environment, even in small quantities. They can be considered as a vector for the transport of metals in the environment and may have the potential to accumulate metal to organisms bodies after ingestion.
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Biodegradace lehčených polyuretanů v půdě a následná analýza produktů rozkladu / Biodegradation of lightweight polyurethanes in soil and subsequent analysis of their degradation products

Pražanová, Kateřina January 2018 (has links)
According to the Waste Framework Directie 2008/98/ES and the Czech law on waste 185/2001 Sb., waste preienton is the main priority in waste management. Using biodegradable plastcs seems to represent a suitable approach in fulflling the strategy. The subject of this diploma thesis is biodegradable lightweight polyurethanes (PURs), which might represent suitable materials for repellent fences in agricultural landscapes. Biodegradaton processes are assumed to begin in the agricultural soil afer their lifetme. The biodegradability of new lightweight PURs (BIO 8-10), presented as material mineralizaton, was tested in agricultural soil under laboratory conditons according to the ASTM Internatonal standard method D5988-03. Afer the nine-month experiment the material with the highest biodegradability (BIO 10) containing starch (28 wt. %) was mineralized to 42.0 ± 4.2 %. Cellulose (the positie control) was completely mineralized; thus, the ialidity criterion (positie control mineralizaton > 70 %) was accomplished. Afer the biodegradability test, degradaton products (residual PURs) were separated from the soil by a two-step method using fuidisaton and fotaton, according to a modifed procedure described in Nuelle et al. (2014). The procedure enabled a subsequent analysis of PUR residues with Fourier transform...
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Estudo da distribuição de metais em plásticos no litoral de São Paulo: avaliação da poluição por meio de análise de pellets / Study of the distribution of metals in plastics at São Paulo coast: an avaliation of pollution with analysis of plastic pellets

Marcela Corrêa Vedolin 17 March 2014 (has links)
A matéria prima das indústrias transformadoras de utensílios plásticos são os pellets de plástico, que recebem quantidades significativas de aditivos os quais possuem metais pesados e elementos tóxicos. Devido à perda desses pellets durante os processos de produção e transporte, tais contaminantes são liberados no ambiente. Este estudo investiga as interações entre os metais dissolvidos em pellets coletados em diferentes praias do litoral de São Paulo. Especificamente, o estudo comparou a realização do método em grânulos virgens, ou seja, aqueles obtidos a partir de uma fábrica de moldagem com os recolhidos das praias. Foram quantificados os elementos: Al, Cr, Cu, Fe, Mn, Sn, Ti e Zn empregando a técnica de espectrometria de emissão atômica com plasma indutivamente acoplado (ICP-OES). Os polímeros foram solubilizados via digestão ácida (EPA3050B). As concentrações dos metais exibiram um elevado grau de variabilidade, sendo Al e Fe os elementos de maiores concentrações 58,63 mg kg-1, praia de Tabatinga e 391,56 mg kg-1, praia de Itaguaré, respectivamente. Diferenças de afinidades entre os metais para os pellets coletados no ambiente e aqueles obtidos diretamente a partir de uma processadora de plásticos (virgem) também foram identificados. A adsorção de metais em pellets coletados é maior em relação aos pellets virgens, isso ocorre devido ao desenvolvimento de sítios de adsorção na superfície para realização de foto-oxidação, incrustação e deposição de sedimentos finos e/ou partículas durante a exposição a condições ambientais. Este estudo demonstrou que pellets de plástico têm o potencial acumular e transportar metais no ambiente marinho, mesmo em pequena quantidade. Eles podem ser considerados como um vetor para o transporte de metais no meio ambiente, e podem ter o potencial de acumular metais em organismos após a ingestão. / The raw material of plastic industries is plastic pellets, which receive significant amounts of additives which contain heavy metals and toxic elements. Due to the loss of these pellets during the processes of production and transportation, such contaminants are released into the environment. This study investigates the interactions between metals dissolved in pellets collected in different beaches of the coast of São Paulo state. Specifically, the study compared the performance of the method in virgin granules, ie, those obtained from a molding factory with those collected from the beaches. The following elements quantified: Al , Cr , Cu , Fe , Mn , Sn , Ti and Zn in samples of virgin pellets supplied by Braskem, manufacturer of resins, employing the technique of Inductively coupled plasma atomic emission spectroscopy ( ICP - OES .) The polymers were solubilized via acid digestion (EPA3050B). The metal concentrations exhibited a high degree of variability being Al and Fe elements with higher concentrations: 58.63 mg kg-1 at Tabatinga beach and Fe 391.56 mg kg-1, at Itaguaré beach. Affinity differences between metals for pellets collected in the environment and those obtained directly from a processor of plastics (virgin) were also identified. The maximum adsorption for virgin pellets ranged between 14.09 mg kg-1 (polyethylene, used as control) to 58.63 mg kg-1 for Al. However, for the other elements except Fe, the concentrations were below the limit of quantification. The metal adsorption on pellets collected is greater compared to virgin pellets. This is due to the development of viable local surface for performing photo-oxidation, scaling and deposition of fine sediments and/or particles during exposure to environmental conditions. This study demonstrated for the first time, that the plastic pellets have the potential to accumulate metals and transporting the marine environment, even in small quantities. They can be considered as a vector for the transport of metals in the environment and may have the potential to accumulate metal to organisms bodies after ingestion.

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