Tesis: "Microplastics"

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Klein, Sascha. "Microplastics in Freshwater Systems". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200861.

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Synthetic polymers are one of the most significant pollutants in the aquatic environment, because of abilities such as buoyancy and extreme persistency. Serious effects are expected from so-called microplastics (particle size <5 mm) that are reported in rivers, lakes as well as the ocean and that accumulate in sediments worldwide. In this thesis the abundance of microplastics in river shore sediments in the Rhine-Main area of Germany was studied. Therefore, a new method was developed that is based on a sodium chloride density separation with subsequent destruction of natural debris, and identification of the plastic particles by microscopy or Fourier transform infrared spectroscopy (FTIR). Using the improved density separation, microplastics were separated from river shore sediments of 12 sites originating from the river Rhine, the river Main, and the stream Schwarzbach. Large amounts of microplastic particles of up to 1 g kg-1 or up to 4000 particles kg-1 were detected in the shore sediments. The identification by FTIR showed that polyethylene, polypropylene, and polystyrene were the most abundant polymer types in the sediments, covering over 75% of all plastics identified. Transport of microplastics from tributaries to main streams was indicated by the detection of identical pellets in the River Rhine and in the Main mouth. Comparable concentrations detected by sampling one site over a period of two years suggest a constant pollution of the river shore sediments with microplastics. For deeper insights into the sorption process of organic contaminants to synthetic polymers in freshwater systems, batch experiments in synthetic freshwater were conducted to determine sorption kinetics and sorption isotherms for four selected glass state polymers (polycarbonate, poly(methyl methacrylate), polystyrene, and polyvinyl chloride) and six different model substances (carbamazepine, hexachlorocyclohexane (β/γ), 17α-ethynilestradiol, chlorpyrifos, and o,p-dichlorodiphenyltrichlorethane). Sorption to the polymer particles was observed for all contaminants increasing with the KOW values of the contaminants. Because of losses of contaminants in control samples, sorption reaction models could be applied to four out of six contaminants, and isotherms were calculated for three contaminants. Furthermore, influences of the different polymer types used were observed in the experiments. Finally, microplastics separated from sediments were extracted and analyzed by GC/MS and LC-MS/MS using target screening methods and non-target approaches. Different pesticides were identified in the polymer particles, suggesting that microplastics can act as a sink for hydrophobic contaminants. Moreover, several plastic additives such as phthalates or chlorinated flame retardants were identified. For this reason, it is very likely that microplastics act as a direct source for these chemicals in aquatic systems. The results of this thesis stress the urgency for the mitigation of the plastic particles in the aquatic environment.

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2

Sucharitakul, Phuping. "Sources, effects and trophic transfer of microplastics in jellyfish". Thesis, Griffith University, 2021. http://hdl.handle.net/10072/408941.

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A discrepancy between high plastic production rates and low recycling rates contributes to a ubiquitous plastic pollution problem. If this discrepancy persists, it is estimated that approximately 12 billion tons of plastics will accumulate in the environment by 2050. Although many countries have issued policies to limit the utilisation of single use plastics, the COVID-19 pandemic has increased demands for plastics and overwhelmed waste management systems. Thus, plastic pollution will persist, especially in marine environments where most mismanaged plastics accumulate. Plastics in the marine environment slowly disintegrate into microplastics (<5 mm) and adversely affect many animals when ingested. Thus, microplastics have recently been identified as an emerging contaminant of concern internationally, resulting in an exponential growth in the number of microplastic studies within the last decade. Studies in some ecologically important animals such as jellyfish, however, are preliminary. For example, jellyfish are claimed to ingest microplastics via trophic transfer and have been promoted as bioindicators for plastic pollution despite limited evidence. Moreover, although microplastics in the field are covered by biofilms, all jellyfish and microplastic experiments have used virgin microbeads that might underestimate ingestion rates. This thesis, therefore, tested three hypotheses: 1) that jellyfish would ingest microplastics and they would be adversely affected by microplastic ingestion (chapter 2), 2) that jellyfish would mainly accumulate microplastics via indirect ingestion (i.e. trophic transfer) and biofilms would promote ingestion rates (chapter 3), 3) that jellyfish would be useful bioindicators of microplastic pollution and treated wastewater would be a significant source of microplastics in an estuary (chapter 4). Medusae of Aurelia coerulea were exposed to 2,000 polystyrene microbeads L-1 and determined numbers of microbeads ingested. In addition, impacts of microbead ingestion on respiration rates and histology of their gut tissues were assessed (Chapter 2). No tissue damage was observed and respiration rates were unaffected by ingestion of microbeads. Importantly, the medusae ingested less than 0.2% of microbeads offered, egested microbeads within eight hours and stopped ingesting the microbeads after 16 hours, suggesting that the medusae may recognise virgin microbeads as non-food items. I, therefore, exposed the medusae to microbeads with photosynthetic biofilms, microbeads with heterotrophic biofilms and virgin microbeads (Chapter 3). Medusae ingested more microbeads with photosynthetic biofilms than microbeads with heterotrophic biofilms or virgin microbeads. The results highlight that the use of aged microbeads in experiments is important as the ingestion rates may be underestimated if virgin microbeads are used. Although jellyfish are claimed to acquire microbeads via trophic transfer, no studies had tested whether trophic transfer is a dominant pathway as jellyfish can also ingest microplastics directly from their surrounding water. Thus, I exposed ephyrae of Aurelia coerulea to aged microbeads (to test direct ingestion) and to Artemia nauplii fed aged microbeads (to test trophic transfer), and quantifued numbers of microbeads in the gastrovascular cavities (Chapter 3). I found that the ephyrae ingested 35 times more microbeads via trophic transfer than direct ingestion, suggesting that trophic transfer is the primary pathway by which jellyfish acquire microbeads. Furthermore, I investigated whether jellyfish in the field are susceptible to microplastic ingestion and whether jellyfish can be bioindicators of microplastic pollution. Water samples and medusae of Chrysaora cf pentostoma were collected nearby and distant from treated wastewater diffusers in two estuaries (the Gold Coast Broadwater and the Tweed River Estuary) that receive contrasting amounts of wastewater, to test whether microplastics in the guts of medusae represented those in the environment (Chapter 4). Only 83% of the medusae sampled contained microplastics and types and colours of microplastics in the gastrovascular cavities of jellyfish differed to those in the surrounding water. Thus, medusae are not good bioindicators of microplastic pollution because not all medusae acquire microplastics and the microplastics they accumulated did not reflect those in their environment. I also tested whether the released treated wastewater would have significant effects on microplastic concentrations and compositions in the receiving waters of the estuaries as wastewater treatment plants are claimed to be one of the significant sources of microplastics. I found no significant difference between microplastic concentrations and compositions nearby and distant from wastewater releases in either estuary. Thus, treated wastewater had no detectable impacts on microplastic concentrations and compositions in the receiving waters. Results from both laboratory and field experiments (Chapter2; Chapter 3; Chapter 4) strongly indicated that jellyfish accumulate relativly small amounts of microplastics and are poor bioindicators for microplastic pollution.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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3

Sabienski, Lina. "Characterization of microplastics in wastewater". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-86249.

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This study aims to detect how many microplastics and what kind are released from the wastewater treatment plant (WWTP) Skebäck, in Örebro. The study was limited to the analysis of three filters with 50 μm mesh size and one filter with 300 μm mesh size. The samples were taken at different times, two in the fall of 2019 and one in the spring of 2020. Visual characterization was used for the quantification of microplastics, and a lower and upper bound was used. The lower bound represents particles that were deemed identifiable as plastic with high certainty, while the upper bound also includes particles that may have been microplastic. An additional ATR-FTIR analysis was performed on selected microplastics >300 μm. The presence of microplastics in the effluent from Skebäcks WWTP could be confirmed. The quantity of microplastics per m3 (MP/m3) trapped on the 50 μm filters were quantified in a range between 0 MP/m3 to 291 MP/m3 for the lower bound, and 72 MP/m3 to 435 MP/m3 for the upper bound. The 300 μm filter had considerably less microplastics than the 50 μm filter with 1.8 MP/m3. The quantification of fibers on the 50 μm filter and 300 μm filters was not possible due to high blank contaminations. According to the concentration of 63 MP/m3 of the lower bound count on the 50 μm filters and the amount of water flowing through Skebäck in 2019, 17 818 935 m3, 1.1 billion microplastic particles were released into Svartån that year. In comparison the highest value of the upper bound count, 435 MP/m3, gave a release of 7.7 billion microplastic particles. Using the concentration of the 300 μm filter 1.8 MP/m3, 32 million microplastics/year were released from Skebäck in 2019. The amount of spheres 50-300 μm released in the effluent from Skebäck was estimated to be 3.7 kg in 2019.

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4

Cole, Matthew. "The impacts of microplastics on zooplankton". Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15288.

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In recent years there has been growing environmental concern regarding ‘microplastics’: microscopic plastic granules, fibres and fragments, categorised as <1 or <5 mm diameter. Microplastics are manufactured to be of a microscopic size, or derive from the photo- and mechanical degradation and subsequent fragmentation of larger plastic litter. Microplastics debris has been identified in the water column and sediments of marine and freshwater ecosystems across the globe, although difficulties in sampling and isolating smaller particulates has resulted in the abundance of <333 µm microplastics being under-reported. Microplastics are bioavailable to a range of aquatic organisms, including fish, seabirds and benthic invertebrates, and can be trophically transferred. The consumption of plastic debris can result in gut blockages, heightened immune response and a loss of lipid reserves. The potential risk to food security, and thereby human health, has led regulators to call for better understanding of the fate and effects of microplastic debris on marine life. Here I tested the hypothesis that microplastics can be ingested by and may negatively impact upon zooplankton. Zooplankton encompass a range of aquatic animals that form a key trophic link between primary producers and the rest of the marine food web. I used a suite of feeding experiments, bio-imaging techniques and ecotoxicological studies to explore the interactions and impacts of polystyrene microplastics on marine zooplankton. My results demonstrate that a range of filter-feeding zooplankton taxa, including copepods and bivalve and decapod larvae, have the capacity to ingest microplastics. Microplastics significantly reduced algal feeding in the copepods Centropages typicus and Calanus helgolandicus. With prolonged microplastic exposure C. helgolandicus produced smaller eggs with reduced hatching success, and had reduced survival owing to declining energetic reserves. Microplastics egested by copepods significantly altered the properties and sinking rates of faecal pellets, with potential repercussions for marine nutrient flux. This investigative work highlights that microplastics pose a significant risk to the health of animals at the base of the marine food web.

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5

Rodrigues, Mariana Oliveira. "Impacts of microplastics in freshwater systems". Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21469.

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Mestrado em Toxicologia e Ecotoxicologia
Plastics, in particular microplastics (particles with dimensions < 5 mm), are a widespread and persistent pollutant constituting an emerging scientific and societal issue. Its characteristics allied to an inadequate management contributes to their accumulation in aquatic systems, reaching high densities. Moreover, they can also interact with environment affecting economy, human health and aesthetics. However, most of scientific studies have been focused in marine environment while scarce knowledge exists regarding freshwater systems, including in Portugal. Hence, this study aimed to contribute to fill this gap of information both in uniformization of methodologies of isolation of microplastics (MPs) in water samples as well as on the MPs’ characterization in a Portuguese freshwater system. Thus, the first part of this study aimed to assess the effectiveness of distinct separation methods including density separation methods (sucrose, olive oil and zinc chloride) as well as organic matter degradation methods (hydrogen peroxide and multienzymatic detergent). For that, artificial samples containing the eleven most common types of plastics were prepared, subjected to the different methods and then polymers were detected, quantified and identified using a stereoscope microscope and Fourier transform infrared spectroscopy (FTIR). Among the several tested methods, the most cost-effective was the method of wet peroxide oxidation with addition of zinc chloride. Hence, this study highlights the importance of the use of zinc chloride both in the processing of sediment and water samples. In a following step, the abundance and distribution of MPs in the water and sediment of Antuã river were determined by applying the separation method identified as the most effective previously. The abundance of MPs in water varied from 5 – 8.3 mg m-3 or 58 – 193 items m-3 in March and from 5.8 – 51.7 mg m-3 or 71 – 1265 items m-3 in October. In sediments, the abundance of MPs varied from 13.5 – 52.7 mg kg-1 or 100 – 629 items kg-1 in March and from 2.6 – 71.4 mg kg-1 or 18 – 514 items kg-1 in October. It shows that this river is severely impacted by MPs, in orders similar to that found in marine/coastal environments. A spatial and temporal variation was observed dependent on seasonal conditions, flow velocity and anthropogenic pressure. Thus, this study emphasizes the importance of rivers as carriage systems of MPs, and highlight the potential impacts of MPs as emerging contaminants on freshwater systems.
Os plásticos, em particular os microplásticos (partículas com dimensões <5 mm), são poluentes ubíquos e persistentes que constituem uma preocupação científica e social emergente. As suas características, aliadas a uma gestão inadequada, contribuíram para a sua acumulação nos sistemas aquáticos, podendo atingir elevadas densidades. Estas partículas podem interagir com o ambiente, afetando a economia, a saúde humana e a estética. No entanto, a maioria dos estudos científicos tem-se focado no ambiente marinho, sendo o conhecimento sobre os sistemas de água doce escasso, incluindo em Portugal. Deste modo, este trabalho pretende contribuir para esta lacuna de informação, tanto ao nível da uniformização de metodologias de isolamento de microplásticos (MPs) em amostras de água como na caracterização de MPs num sistema de água doce português. Assim, numa primeira fase este estudo pretendeu avaliar a eficácia de diferentes métodos de separação, incluindo métodos de separação por densidade (açúcar, azeite e cloreto de zinco), bem como métodos de degradação de matéria orgânica (peróxido de hidrogénio e detergente multienzimático). Neste sentido, amostras artificiais contendo onze tipos de plásticos pertencentes aos polímeros mais comuns foram preparadas e submetidas aos diferentes métodos, procedendo-se posteriormente à quantificação e identificação dos polímeros usando um microscópio estereoscópico e um espectroscópio de infravermelhos com transformada de Fourier (FTIR). De entre os vários métodos testados, aquele que revelou o melhor custo-eficácia foi o método da oxidação com peróxido de hidrogénio e adição de cloreto de zinco. Este estudo enfatiza a importância do uso do cloreto de zinco tanto no processamento de amostras de sedimento como de água. Numa fase seguinte do estudo, determinou-se a abundância e distribuição de MPs na água e sedimento do rio Antuã, aplicando o método de separação identificado como o mais eficaz anteriormente. A abundância de MPs nas amostras de água variou entre 5 – 8.3 mg m-3 ou 58 – 193 items m-3 em Março e entre 5.8 – 51.7 mg m-3 ou 71 – 1265 items m-3 em Outubro. No sedimento, a abundância de MPs variou entre 13.5 – 52.7 mg kg-1 ou 100 – 629 items kg-1 em Março e entre 2.6 – 71.4 mg kg-1 ou 18 – 514 items kg-1 em Outubro. Estes resultados demonstram que este rio está severamente impactado por MPs, com valores semelhantes aos encontrados em sistemas marinhos/costeiros. Foi ainda observada uma variação espacial e temporal, dependente da estação do ano, do caudal do rio e da pressão antropogénica. Deste modo, este estudo vem enfatizar a importância dos rios como sistemas de transporte de MPs e realçar os potenciais impactos dos MPs como contaminantes emergentes nos ecossistemas aquáticos dulçaquícolas.

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Santana, Marina Ferreira Mourão. "Effects of microplastics contamination on marine biota". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-20032016-174906/.

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Microplastic pollution (particles < 5mm) is one of the most widespread impacts from modern society. Here, microplastic impacts were investigated through experimental assessments considering different exposure scenarios using mussels and micro-PVC as models. These aimed to investigate mussels\' physiological signs of stress under acute and chronic exposures and microplastics transference, assimilation and retention along food chains. In acute exposures, PVC intake affected mussels\' physiology over time, also influenced by plastics additives and particle concentration. Interactions among exposure factors (time, presence of additives and concentration) were more relevant than their individual effect, indicating the singularity of each contamination scenario. Long-term contact did not affect mussels, indicating the influence of time to acclimation. Microplastics were not assimilated and retained along food chains, but only biotransferred from prey tissues to predators\' tract, showing the influence of prey contamination on the effectiveness of microplastics biotransference. To evaluate risks in nature, microplastic ingestion was investigated in mussels from the Santos Estuary. Santos Estuary contained microplastics in 75% of sampled mussels, an issue of environmental and human concern. This study illustrated that microplastics impacts on mussels vary with microplastics characteristics, exposure scenario and species vulnerability, highlighting the need for more toxicological and risk evaluation studies.
Os microplásticos (< 5mm) são um dos impactos mais difundidos da sociedade moderna. Aqui, eles foram estudados em ensaios experimentais, considerando diferentes composições de exposição de mexilhões à micro-PVCs. O objetivo foi investigar: sinais fisiológicos de estresse sob exposições aguda e crônica; e transferência, assimilação e retenção de microplásticos em cadeias tróficas. Para avaliar seus potenciais riscos na natureza, a ingestão por mexilhões também foi investigada no Estuário de Santos. As exposições agudas afetaram a fisiologia dos mexilhões, sendo influenciadas pelo tempo e concentração de exposição, e pela presença de aditivos plásticos. Interações entre esses fatores (tempo, concentração e aditivos) foram mais relevantes do que eles individualmente, sugerindo a singularidade dos cenários de poluição. A exposição de longo prazo não afetou os mexilhões, indicando a influência do tempo na aclimatação ao microplástico. O PVC não foi assimilado e retido nas cadeias tróficas, mas biotransferido do tecido das presas para o trato dos predadores, mostrando a influência do estado da presa na efetividade da biotransferência dos microplásticos. Dentre os mexilhões coletados, 75% estavam contaminados, revelando uma importante questão socioambiental. Esse trabalho ilustrou a complexidade dos impactos dos microplásticos para a biota marinha, ressaltando a necessidade de mais estudos sobre seus riscos.

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Avio, Carlo Giacomo. "Ecotoxicological risk of microplastics for marine organisms". Doctoral thesis, Università Politecnica delle Marche, 2016. http://hdl.handle.net/11566/243067.

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La presenza di Microplastiche (MP) negli oceani rappresenta una problematica emergente per l’ecosistema marino; è ormai stato dimostrato che le MP possono essere ingerire da diverse specie di organismi, ma non è stata ancora dimostrata la capacità di trasferimento trofico e di accumulo di queste microparticelle, e sono ancora molto carenti le informazioni sui effetti avversi indotti. In questo lavoro di ricerca, il ruolo di alcuni polimeri plastici, come vettori di inquinanti chimici, è stato inizialmente valutato su campioni di macro-plastiche vergini, macro- e micro-plastiche spiaggiate. Tramite esperimenti di laboratorio, sono state invece studiate sia le cinetiche di adsorbimento del pirene e del cadmio in MP di polietilene (PE) e polistirene (PS), che la loro capacità di trasferire i composti adsorbiti ai mitili, Mytilus galloprovincialis. In questi organismi esposti sono stati analizzati diversi effetti a livello molecolare, biochimico e cellulare, incluse le risposte immunologiche, le alterazioni lisosomiali, la proliferazione perossisomiale, le difese antiossidanti, gli effetti neurotossici, genotossici oltre che il profilo di espressione genica. E’ stato inoltre ottimizzato e applicato un nuovo protocollo per l'estrazione e caratterizzazione (FT-IR) delle MP su diverse specie di pesci e invertebrati del Mar Mediterraneo. I livelli di IPA maggiori sono stati misurati nelle micro e macro-plastiche spiaggiate, mentre un efficiente assorbimento delle sostanze chimiche è stato confermato, sia per il PE che PS, con una modalità di adsorbimento tempo e dose-dipendente. Indagini istologiche hanno rivelato la presenza di MP nell’emolinfa, nelle branchie e nei tessuti digestivi dei mitili. Gli IPA adsorbiti sono stati rilasciati dalle MP e accumulati nei tessuti dei mitili che hanno mostrato alterazioni di diversi biomarker sia molecolari che cellulari. Il protocollo di estrazione sviluppato ha permesso di dimostrare la presenza di MP nello stomaco e, per la prima volta, nel fegato di cefali esposti. Studi sul campo hanno evidenziato la presenza di particelle nel 38% degli organismi selvatici analizzati, con una maggior frequenza di MP sotto forma di frammenti e linee, costituiti preferenzialmente da PE, PS e nylon. In conclusione, questa tesi fornisce nuove informazioni sui rischi ecotossicologici delle MP per gli organismi marini oltre che un’importante linea di base sul livello di contaminazione da MP nel biota Mediterraneo.
Microplastics (MPs) are a growing but still unexplored environmental concern for marine organisms. Although several species can ingest MPs, a clear evidence of their accumulation pathways, trophic transfer and adverse effects is still lacking. In this thesis, the potential role of MPs as vectors of chemical pollutants was initially evaluated in virgin macroplastics, beached macro- and microplastics; laboratory experiments further characterized adsorbing kinetics of pyrene and cadmium on polyethylene (PE) and polystyrene (PS) MPs, and their capability to transfer adsorbed pyrene to mussels Mytilus galloprovincialis. In these organisms, several molecular, biochemical and cellular effects were analyzed in term of immunological responses, lysosomal alterations, peroxisomal proliferation, antioxidant and neurotoxic effects, genotoxicity and gene expression profile. A new protocol for extraction and FT-IR characterization of MPs in marine organisms was optimized and applied to several species of Mediterranean fish and invertebrates. Load of PAHs was higher in weathered and micron-sized particles, and an efficient adsorption of chemicals was confirmed with a time- and dose-dependent trend for both PE and PS. Histological analyses revealed occurrence of ingested MPs in haemolymph, gills and digestive tissues of mussels. Adsorbed PAHs were desorbed from MPs and bioavailable for mussels that showed many altered several molecular and cellular biomarkers. The developed extraction protocol allowed to demonstrate the presence of MPs in the stomach and, for the first time, in liver of exposed Mugil cephalus. Field studies highlighted the occurrence of MPs in 38% of analyzed wild organisms, mostly represented by fragments and lines, while PE, PS and nylon were the dominant polymers. In conclusion, this thesis provides new insights on the ecotoxicological risks of MPs for marine organisms and an important baseline for assessing the level of MPs contamination in Mediterranean biota

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Wu, Pengfei. "Occurrence, determination and environmental fate of microplastics in aquatic system". HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/780.

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The current period of human history is considered to be the plastics age due to its versatile characteristics, especially the lightweight, durability and low production cost. Plastics can be manufactured to suit multifarious functions, for example, for personal care products, food/drink storage and medical purposes. Thus, the use of plastics is unavoidable now, finally contributing to the severe pollution worldwide. In 2018 alone, the global plastics production amount has exceeded 359 million tons, around 10% of which ultimately become waste persisting in the environment. When plastic wastes exposed to the sun's radiation, climate change and mechanic abrasion, degradation and fragmentation may occur. Once the size of the fragmentation products is less than 5 mm, they are commonly defined as microplastics (MPs) by the National Oceanographic and Atmospheric Administration. Currently, microplastics have been regarded as the most pervasive environmental pollution problems, not only because of their physical hazards but also due to their interactions with other pollutants in the environment. Pollution can be attributed by the release of additives from MPs, as well as the MPs with adsorbed toxic contaminants. Moreover, MPs additives together with adsorbed chemicals can be easily uptaken by animals, which may cause further propagated effects on the ambient ecosystem. Through the bioaccumulation and biomagnification effect, MPs can even be accumulated in the organisms from different trophic levels and cause serious impacts on aquatic ecology and human health. Despite growing number of evidences that have confirmed the presence and consequential effects of microplastics, researches on microplastic pollution are still lacking. Investigations on occurrence, determination and environmental fate of MPs in aquatic systems are clearly needed. Therefore, the major objective of this study is to elucidate the distribution of MPs in natural environment, to develop novel determination methods to characterize the micro-(nano-)plastics (MNPs), and to study the interactions of MPs with other contaminants in different conditions, as well as their consequential fate in different matrices (e.g. freshwater, cold-blooded intestine, and warm-blooded intestine). The spatial-temporal distribution of the MPs along the Maozhou River was investigated for both the surface water and sediments from 17 sites. Results showed that MPs were widely and unevenly distributed along the river. The MP abundances in dry season ranged from 4.0 ± 1.0 to 25.5 ± 3.5 items·L-1 in water and 35 ± 15 to 560 ± 70 item·kg-1 in sediments, which were relatively higher than those observed in wet season (water: 3.5 ± 1.0 to 10.5 ± 2.5 items·L-1; sediments: 25 ± 5 to 360 ± 90 item·kg-1; p value < 0.05). The dominant types of MPs were identified as: polyethylene (PE, water: 45.0%, sediments: 42.0%), polypropylene (PP, water and sediments: 12.5%), polystyrene (PS, water: 34.5%; sediments 14.5%) and polyvinyl chloride (PVC, water: 2.0%; sediments: 15%). Moreover, metals such as Al, Si, Ca were discovered on the rough surface of the MPs, indicating the interactions between the MPs and the aquatic environment. After obtaining the occurrence of the MPs in the aquatic systems, we proposed an accurate method for MNPs identification and quantification with the employment of the matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). By optimizing the conditions (e.g. the laser energy, matrix, analyte, cationization agent and their ratio), the peaks of PS and polyethylene terephthalate (PET) were successfully identified. A quantitative correlation was built between the normalized signal intensity and ln[polymer concentration], with a correlation coefficient above 0.96 for low-molecular-weight (LM-) polymers and 0.98 for high-molecular-weight (HM-) polymers. Furthermore, two types of environmental MPs samples were prepared, including the particles of an aviation cup as the fresh plastics and the aged MPs extracted from river sediment. By using MALDI-TOF MS, the PS-related micro-(nano-)plastics (in both aviation cup and sediment) consisted of C8H8 and C16H16O oligomers, while the PET-related MNPs (only found in sediment) were identified with compositions of C10H8O4 and C12H12O4. The contents of PS and PET MNPs in sediment were quantified as 8.56 ± 0.04 and 28.71 ± 0.20 mg·kg-1, respectively. Also, the interaction between MPs and bisphenols was investigated. PVC was selected as the representative target because it is comparatively easy to decompose into MPs with the release of additives, especially the bisphenols. The released bisphenols may then be readsorbed by the PVC MPs and cause consequential pollution to the ecosystem. To elaborate on the interactions mechanism, a systematic study was carried out to determine the adsorption mechanisms of five bisphenol analogues (BPA, BPS, BPF, BPB, and BPAF) on PVC MPs. The equilibrium adsorption numbers of the bisphenols on PVC MPs are 0.19 ± 0.02 mg/g (BPA), 0.15 ± 0.01 mg/g (BPS), 0.16 ± 0.01 mg/g (BPF), 0.22 ± 0.01 (BPB), 0.24 ± 0.02 mg/g (BPAF), respectively. Intraparticle diffusion modeling (kinetics) divided the adsorption process into three stages: external mass transport, intraparticle diffusion and dynamic equilibrium. The isotherm results showed a better fit of the adsorption to the Freundlich model. Furthermore, the adsorption mechanisms of the five bisphenol analogues were explored intensively, with respect to hydrophobic interaction, electrostatic force and noncovalent bonds. Besides the adsorption process, the transfer and release behaviors of contaminated MPs are of critically importance in the exploration of their role as culprits and/or vectors for the aforementioned toxicity. Therefore, experiments were performed to examine desorption behaviors and cytotoxicity performance of contaminated MPs in aquatic surroundings and intestinal environment after ingestion by organisms (cold-/warm-blooded). The kinetic study showed that the rate of desorption for bisphenols could be enhanced threefold under simulated warm intestinal conditions. The Freundlich isotherms indicated multiple-layer desorption of the bisphenols on the heterogeneous surfaces of PVC MPs. Hysteresis was detected in the adsorption/desorption of bisphenols in a water environment, but no adsorption/desorption hysteresis was observed in the simulated intestinal conditions of warm-blooded organisms. Due to the enhanced bioaccessibility, the desorption results implied that the environmental risk of contaminated PVC MPs might be significantly increased after ingestion at a high bisphenols dosage. Although with different IC50, the five bisphenols released under the intestinal conditions of warm-blooded organisms can cause higher proliferation reduction in fish and human cell lines than the bisphenols released in water. In summary, this study elucidated the spatial-temporal distribution behaviors of MPs, developed effective determination methods for MNPs revealed the interactions mechanisms of MPs with other contaminants, and explored their consequential fate in different environments. The obtained results are helpful of better understanding on the land-based input of MPs from the intensively affected inland waters, realizing the role of microplastics as both source and carrier for emerging organic pollutants, and providing a novel alternative for MPs determination in future studies.

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Lundström, Johanna. "Spreading of microplastics from artificial turf via stormwater". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277122.

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På senare tid har mikroplaster i hav och sjöar uppmärksammats som ett potentiellt stortmiljöproblem. Idag finns mikroplaster spridda över hela världens vatten från polerna till ekvatorn.År 2016 uppmärksammades konstgräsplaner som den nästa största källan till spridning avmikroplaster till sjöar och vattendrag i Sverige [1]. Fotboll är Sveriges nationalsport och är densporten som står för flest aktivitetstimmar i Sverige. Konstgräs har gjort det möjligt för fler barnoch ungdomar att få fler speltimmar och idag spelar 90 % av alla fotbollsspelare på konstgräs [2].De olika spridningsvägarna för mikroplaster från konstgräsplaner undersöktes med fokus påspridningsvägen via dagvatten. Det finns fler olika reningsmetoder för dagvatten innehållandemikroplaster, en av dessa är granulatfällan, en filterpåse som placeras i en dagvattenbrunn för attfånga upp granulat och konstgräsfibrer som sprids från konstgräsplanen till dagvattenbrunnen.Syftet med denna studie var att optimera reningsmetoden granulatfälla utifrån möjligavattenflöden och dess effektivitet i att fånga upp mikroplaster. Detta undersöktes genomframtagandet av en vattenflödesmodell vid konstgräsplaner med variationer i konstruktion ochgenom fältstudier av granulatfällans effektivitet vid två konstgräsplaner i Storstockholm.Det regn som undersöktes i vattenflödesmodellen var extremregn för ett 10 års regn under 10minuter. Detta för att hitta det maximala flöde granulatfällorna kommer behöva klara av. Vilkavattenflöden som nådde dagvattenbrunnarna var beroende på antalet dagvattenbrunnarplacerade runt konstgräsplanen, i vilket område i Sverige som konstgräsplanen var placerad, detvill säga hur mycket regn som kom, och konstgräsplanens infiltrationsförmåga.Vattenflödesmodellen fungerar som en mall för möjliga vattenflöden vid en specifik plats i Sverigeoch en viss konstruktion av konstgräsplan.De konstgräsplaner som var med i fältstudierna var Skytteholms IP i Solna och Spånga IP iStockholm. Vid varje konstgräsplan placerades 6 granulatfällor med två filterpåsar på varje fälla,den inre med större maskor och den yttre med mindre maskor. Kombinationerna var 200 μm med100 μm, 200 μm med 50 μm och 100 μm med 50 μm. Totalt fångades 10,3 kg mikroplast vidSkytteholms IP och 1,5 kg vid Spånga IP under de 49 dygn granulatfällorna var utplacerade. Avden totala mängden mikroplast viktmässigt i varje granulatfälla fanns minst 99 % i den inrefilterpåsen och maximalt 1 % i den yttre filterpåsen, det vill säga i storleksfraktionen mellan denyttre och den inre filterpåsen.Slutsatserna från denna studie är att vattenflödet till dagvattenbrunnarna placerade runtkonstgräsplaner kan variera mycket på grund av hur konstgräsplanen är konstruerad. Det berorframförallt på konstgräsplanens infiltrationsförmåga och antal dagvattenbrunnar runtkonstgräsplanen. Utifrån de teoretiska vattenflödena och fältstudierna rekommenderas att enfilterpåse med maskstorlek 200 μm används i granulatfällan. Detta utifrån att den inre filterpåsenfångade minst 99 % av de mikroplaster som nådde granulatfällorna, som var större än 50 μm, ochökad risk för igensättning och tillväxt av biofilm på filterpåsarna med mindre maskor. Vidarestudier bör genomföras på granulatfällans vattenflöde över tid, mikroplaster mindre än 50 μm,IIandra spridningsvägar för mikroplaster från konstgräsplaner, förbättrade konstruktioner avkonstgräsplaner och förbättrat underhållningsarbete för att minska spridningen av mikroplasterfrån konstgräsplaner.
In the recent years microplastics in the marine environment has been recognized as a potentiallyimportant environmental issue. Today there are microplastics spread in the waterbodies all overthe world, from the equator to the poles in south and north. In 2016 artificial turf was labeled thesecond largest source of microplastics to the marine environment in Sweden [1]. Football is thenational sport of Sweden and accounts for the majority of the activity hours among the youth inSweden. The artificial turf has made it possible for more children to play football and for them toget more hours on the field. Today about 90 % of the football players play on artificial turf [2].The microplastics pathways to the nature and the marine environment were studied andtreatment methods were developed. One of these methods is the so called granule trap, a filterbag which is placed in a stormwater drainage well to catch the rubber granulates and the artificialturf fibers which can be spread from the artificial field to the drainage system. The aim of thisstudy was to optimize the granule trap for possible waterflows to the stormwater drainage welland its efficiency to catch microplastics. This was researched through field studies of the efficiencyof the granule trap at two artificial turfs in Stockholm and the development of a waterflow modelof an artificial turf with varying construction.The rainfall which was used in the waterflow model was the 10-year storm with a duration of 10minutes. This to find the maximum waterflow the granuletraps must manage. The waterflows tothe stormwater drainage well were dependent on the number of wells placed around the artificialturf, in which area of Sweden the football field was placed, in other words the amount of rain thatfell, and the infiltration capacity of the artificial turf. The waterflow model works as a templatefor possible waterflows at an artificial turf with a certain construction and at a certain location inSweden.The artificial turfs which were examined in the field studies were Skytteholms IP in Solna andSpånga IP in Stockholm. At each football field 6 granuletraps were placed, each loaded with twofilter bags, the inner with larger sized mesh and the outer with smaller sized mesh. The mesh sizecombinations were 200 μm with 100 μm, 200 μm with 50 μm and 100 μm with 50 μm. atSkytteholms IP a total amount of 10.3 kg microplastics were caught and at Spånga IP a total of 1.5kg microplastics were caught during the 49 days the granuletraps were placed at the footballfields. Out of the total amount of microplastics in each granuletrap at least 99 % by mass was inthe inner filter bag and maximum 1 % by mass was in the outer filter bag, in the size fractionbetween the outer and the inner filter bag..In conclusion this study shows that the waterflow to the stormwater drainage wells placed aroundthe artificial turfs vary a lot depending on the construction of the artificial turf. Foremost itdepends on the infiltration capacity of the artificial turf and the number of stormwater drainagewells around the field. With regards to the waterflows from the waterflow model and the resultsfrom the field studies the recommended mesh size for the filter bags is 200 μm. This since at least99 % by mass of the microplastics, which were larger than 50 μm, that reached the granule trapsIVwere trapped in the inner filter bag and the elevated risk of clogging and biofilm growth on thefilter bags with smaller mesh size. Further studies should be conducted on the waterflow throughthe granuletraps over time, microplastics smaller than 50 μm, other pathways for themicroplastics away from the artificial turf, improved constructions of artificial turfs and improvedmaintenance on the artificial turfs to reduce the risk of spreading of microplastics from artificialturfs.

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Bottone, Anna. "Analyzing microplastics in soils : Evaluating canola oil extractions". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-165179.

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Small fragments of artificial polymers (microplastics, MPs) has been reported for multiple environmental matrices from our planet. The omnipresent existence of these microplastics even in remote polar areas have raised concern about their potential environmental impacts and created a need for effective and standardized analytical methods targeting their detection in environmental samples. So far, no methods have been developed for detecting microplastics in organic-rich soils. In this master thesis, I evaluate two analytical methods (both based on canola oil extractions) targeting microplastics in two contrasting soil matrices; one mineral rich (sandy mineral soil from a Podzol) and the other by organic matter (sample from a Histosol). I hypothesize that the detection of microplastic has a bias that depends on specific plastic particle properties (size, polymer type and morphology) as well as on the organic content of soil samples. My results show that the recovery of added plastics is strongly dependent on particle size and diminishes with decreasing microplastics length. This result was repeated by both extraction approaches. Polymer shape and soil characteristics (organic matter content) affect MPs recovery if oil extractions are conducted without pre-treatment (oxidation) step. Here, fibers proved most difficult to detect and low recoveries suggested that the method was not applicable to organic rich samples. The addition of a pretreatment step including oxidation with sodium hypochlorite improved recoveries for organic rich samples and removed the effect of soil type and polymer shape. Hence, the use of a pretreatment is essential to extract MPs from organic-rich soils, but it also decreases the overall recovery for all type of studied polymers and mostly fibers. My study suggests that there is a substantial bias when detecting MPs in soils that is causing a general underestimation, especially for small, fibrous particles in organic rich soils.

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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.

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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 marines
Oceanic 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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Houck, Blane. "Identification and Characterization of Microfibers in Wastewater Discharging into Lake Erie". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1555701070926725.

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Karlsson, Sjögren Isabelle. "Characterization of microplastics in storm water in Örebro, Sweden". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-84460.

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Microplastic is a widespread pollutant in marine and fresh water systems. A major pathway by which microplastics end up in these systems is via storm water. Storm water is generated as precipitation drain off of impenetrable surfaces like paving. Microplastic analysis of storm water make up a good foundation for better understanding what sources and factors contribute to microplastic pollution in marine and fresh water systems. This study puts emphasis on characterization and quantification of microplastics through visual characterization. As visual characterization is a subjective form of analysis, the characterization was performed based on guidelines in order to minimize the risk of identifying false positives. The concentration of microplastic was found to be higher in the current study than in comparison to larger water bodies and storm water streams in less urban areas. Fragments, i.e. irregular shaped particles with the appearance of being broken from a larger piece of litter, were found to be the most abundant type of microplastics, pointing at littering as a major source of microplastics in storm water.

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Li, Ran. "Tracking Microplastics from Artificial Football Fields to Stormwater Systems". Thesis, Stockholms universitet, Institutionen för naturgeografi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170290.

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Microplastic pollution as a global environment problem in marine systems has substantially raised public concern in recent years. In 2016, the Swedish Environmental Protection Agency performed a study about potential sources and pathways of microplastics spreading to the marine environment. Microplastics from artificial turfs have been recognized as the second most important source of microplastic emission in Sweden. Between 1640 to 2460 tons per year of microplastics are estimated to be lost from artificial turfs. The lost microplastics are potentially transported to stormwater wells by runoff during rainfall events, eventually reaching marine environments. This study aims to track microplastics from artificial turfs to stormwater wells. Since the research of microplastic in stormwater has so far shown to be limited, field work and laboratory analysis have been developed in this study. Four artificial football fields located in Stockholm municipality were taken as sampling sites. First, pathways for microplastics from artificial turfs to stormwater were investigated. Second, the characteristics of microplastic granulates infill used in the football fields have been analyzed. Finally, stereo microscopy was used to visually identify microplastics in stormwater. The results showed that rainfall as a driving force of runoff process contributes to microplastics transport from artificial turfs to stormwater. During this transport process, a fraction of microplastics is captured by the soil. The size of microplastic granulates identified not only in stormwater but also in stormwater sediments is typically between 1 mm to 3 mm. Due to its limitations, stereo microscopy is quite a subjective method for identifying microplastics and thus not suitable for quantitative analysis, since microplastic particles are comparable in size to and visually difficult to differentiate from organic particles co-occurring in stormwater. In order to accurately quantify the amounts of microplastics transported to stormwater systems from artificial turfs, it is necessary to develop new methods for microplastics identification. This study presented an attempt in this direction, highlights its limitations, and discusses more suitable alternatives.

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15

Leistenschneider, David. "Physical and chemical toxicity of microplastics on marine organisms". Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS283.

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L'objectif de cette thèse de doctorat est de mieux comprendre l'impact chimique et physique du plastique sur les organismes marins. La toxicité chimique du plastique provient soit de la lixiviation des produits chimiques des plastiques, soit de l'adsorption de polluants à la surfaces des plastiques. Étant donné que les expériences de lixiviation dans la littérature ont été réalisées avec des temps de lixiviation courts, des lixiviations jusqu'à 8 mois ont été réalisées. La toxicité et la composition en éléments inorganique des lixiviats ont été analysées. L'adsorption des polluants à la surface des plastiques a été principalement étudiée en laboratoire et s'est concentrée sur l'environnement marin. Par conséquent, une expérience in situ, le long de neuf fleuves européens, a été réalisée afin d'observer l'ampleur de l'adsorption des polluants inorganiques et organiques ainsi que leur toxicité. Les articles évaluant l'impact physique du plastique utilisent souvent des concentrations qui ne reflètent pas celles trouvées dans l'environnement. Par conséquent, une expérience chronique avec des concentrations et formes de microplastiques représentatives de l'environnement a été réalisée afin de mieux comprendre leur toxicité dans l'environnement
The objective of this PhD thesis is to better decipher the chemical and physical impact of plastic on marine organisms. Plastic chemical toxicity either originates from the leaching of plastics chemicals or through the adsorption of pollutants at plastic surfaces. Since leaching experiments in the literature were performed with short leaching time, leaching until 8 months was performed. The subsequent toxicity and inorganic composition of the leachates were analyzed. Pollutants adsorption on plastic surfaces was mainly studied in laboratories and focused on the marine environment. Therefore, an in situ experiment, along nine European rivers, was realized in order to observe the depth of inorganic and organic pollutants adsorption and their subsequent toxicity. Articles assessing the physical impact of plastic often use concentrations decorrelated from the environment. Therefore, a chronic experiment with environmentally relevant concentrations and shape of microplastics was performed in order to better decipher their current toxicity in the environment

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NAVA, VERONICA. "Microplastics in freshwater systems: characterization, quantification and interaction with aquatic organisms". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/363436.

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Gli ecosistemi acquatici risentono di differenti impatti antropici. Tra questi, la presenza di plastiche e microplastiche rappresenta una problematica ambientale diffusa. La maggior parte delle ricerche svolte fino ad ora si è concentrata specialmente sull’ambiente marino e le informazioni riguardanti la presenza e gli effetti di questi contaminanti nei sistemi di acqua dolce sono limitate. Inoltre, non esiste ancora nella comunità scientifica un’armonizzazione delle procedure di campionamento e dei protocolli analitici per la caratterizzazione e quantificazione delle plastiche in ambiente acquatico. Questo rende il confronto dei dati ottenuti da ricerche differenti complesso. Oltre a questi aspetti, sono necessari ulteriori studi per comprendere l’influenza che le (micro)plastiche possono esercitare sugli organismi e sul funzionamento degli ecosistemi acquatici. In particolare, le informazioni relative agli effetti sugli organismi dei più bassi livelli trofici sono molto limitate. Dato questo contesto, nella presente tesi di dottorato sono illustrati quattro lavori che hanno contribuito ad aumentare le informazioni disponibili sulle (micro)plastiche in ambienti di acqua dolce. Il primo lavoro si è concentrato sull’utilizzo della micro-spettroscopia Raman per l’identificazione della composizione polimerica dei materiali plastici, la cui determinazione è fondamentale per una corretta e adeguata caratterizzazione di questi inquinanti. Al fine di aumentare le conoscenze relativamente a questa tecnica, è stato sviluppato e descritto un database, liberamente fruibile, di spettri di diversi polimeri plastici ed additivi che possono essere comunemente individuati in ambiente. Inoltre, è stato anche sviluppato un nuovo pacchetto in R che fornisce diversi strumenti per l’analisi e l’identificazione di spettri. I vantaggi e gli svantaggi della spettroscopia Raman sono stati evidenziati e sono state fornite utili indicazioni per studi futuri. Il secondo lavoro si è invece concentrato sulla determinazione e caratterizzazione di plastiche e microplastiche nelle acque superficiali di laghi di diverse regioni del mondo. Infatti, sono stati analizzati campioni provenienti da 38 laghi (distribuiti in 28 Stati), selezionati in modo da essere rappresentativi di diverse condizioni limnologiche e differente grado di impatto antropico. I campioni sono stati prelevati seguendo una procedura standardizzata che ha permesso di ottenere in questo modo dati realmente confrontabili. Con questo dataset globale sono state valutate non solo le concentrazioni ma anche le caratteristiche delle particelle plastiche. Inoltre, l’analisi dei dati ha permesso di evidenziare la presenza di una relazione positiva tra la concentrazione di (micro)plastiche e attributi del bacino idrografico, espressione di impatto antropico. Oltre a ciò, è stato evidenziato come laghi profondi, con estesa area superficiale ed elevato tempo di ritenzione delle acque tendano ad accumulare un numero maggiore di microplastiche. Nell’ultima parte della tesi, è stata invece investigata la relazione tra microplastiche e microalghe. Questo argomento è stato approfondito attraverso un duplice approccio: dapprima è stata svolta un’estesa ricerca bibliografica e successivamente è stata condotta una sperimentazione in mesocosmi per valutare la colonizzazione di diversi polimeri plastici in ambienti con differenti caratteristiche chimico-fisiche e ambientali. Questo esperimento ha permesso di evidenziare come le microplastiche siano in grado di supportare la crescita di molte e diverse specie microalgali. Non è stata però evidenziata una specificità nella colonizzazione di polimeri differenti. Infatti, è stato mostrato come, non la composizione polimerica del substrato, ma le specie esistenti nei diversi mesocosmi e le differenti condizioni ambientali rappresentino i principali fattori che determinano ed influenzano la composizione specifica del biofilm algale.
Among the multiple stressors that affect aquatic ecosystems, plastic pollution is deemed a widespread and pervasive environmental issue. The majority of the research has been conducted in marine environments and information about the occurrence and effects of these pollutants in freshwater systems is scattered. Moreover, there is a lack of consensus on sampling and analytical procedures for their characterization and quantification, which makes comparison among studies difficult. Besides, more research is needed to assess the influences of plastics and microplastics on ecosystem functions and aquatic organisms, especially focusing on lower trophic levels. Given these gaps, the present project describes four pieces of work that contribute to enhancing our knowledge about plastics and microplastics in freshwater ecosystems. Firstly, since polymer identification constitutes a fundamental step in plastic analysis, the suitability of Raman spectroscopy for polymeric characterization was examined, and a free database with Raman spectra of plastics complemented by a new R package with tools for their processing were developed and described. Advantages and drawbacks of this technique were discussed, with a particular emphasis on plastic additives, which are contained in the majority of polymers but are still poorly investigated, and a catalog with detailed information about peaks of most common plastic polymers was reported to provide guidance for further studies. Secondly, microplastic occurrence in surface water of different freshwater systems was assessed. Indeed, water samples of 38 lakes from 28 different countries covering an assortment of limnologically diverse freshwater ecosystems under varying levels of anthropogenic stress were collected, following a common protocol. This global investigation allowed obtaining comparable data about plastic concentration and features. Moreover, the results suggested the existence of a relationship between urban-related attributes of lakes/watersheds and the plastic concentration but also highlighted as large and deep lakes with high retention times accumulated plastic debris at higher concentrations. Lastly, the relationship between microplastics and microalgae was investigated. This was pursued by combining a critical review of the literature with an experimental approach aimed at analyzing the phytobenthos establishment on two different plastic polymers using a multi-site mesocosm system. This experiment highlighted that microplastics supported the growth of a rich and diversified community of microalgae, showing that many species could coexist on the surface of relatively small plastic items. Species-specificity in the colonization of the different plastic polymers was not observed. Indeed, local species pool and nutrient concentration rather than polymeric composition seemed to be the determinant factors defying the community diversity.

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Lee, Hiu-yan Jessica y 李曉恩. "Plastics at sea (microplastics) : a potential risk for Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/194557.

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Plastics are cheap and convenient materials that are widely adopted in our daily applications. High production and consumption of plastics, however, are resulting in the issue of marine plastic pollution. Plastic debris is often divided into two categories: macroplastics and microplastics. Macroplastic is a well-known international problem to the world’s oceans, while microplastics often receive less attention. Many coastal areas and remote islands are suffering from plastic pollution. Marine plastic debris is responsible for negative impacts on organisms and the environment, including entanglement, ingestion, absorption of toxic chemicals, and transportation of invasive species. Human society and the economy may also be threatened. It is noticed that impacts caused by microplastics are comparatively more critical than those caused by macroplastics. Microscopic size and large surface area to volume ratio increase the potential for microplastics being ingested or used as vectors to absorb chemicals. Micro particles may enter the circulatory system, cause damage to cells and tissues, and release contaminated chemicals to the body, and hence result in health and safety issues. Ingested plastics may undergo bioaccumulation and pass up the food web, which may influence the entire ecosystem as well as human populations. Guangdong province is the largest plastic production centre in Mainland China. Any discharge from Guangdong province will enter the Pearl River and move downstream to the mouth of the estuary where Hong Kong is located. Hong Kong, especially it’s western waters, is directly susceptible to discharge from Mainland China. Data of plastics collected from beaches illustrated that higher quantities of plastic pellets have been collected from the western part of Hong Kong. This implies Hong Kong is suffering from plastic pollution generated from the Pearl River. Hong Kong may also receive overseas plastics carried by ocean currents and monsoon winds, which may have a stronger effect on the southern and eastern waters. There are many valuable marine biota and environments in Hong Kong. The presence of microplastics may pose a significant threat to the entire marine ecosystem and food chain. It is necessary to take action on the prevention and mitigation of the impacts of microplastics. Efforts should be made at national and international levels, and all sectors are responsible to take appropriate actions.
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Environmental Management
Master
Master of Science in Environmental Management

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Uhlig, Kelley Ann. "Partitioning of Hydrophobic Organic Contaminants and Microbial Communities on Microplastics". W&M ScholarWorks, 2019. https://scholarworks.wm.edu/etd/1563898639.

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Microplastic contamination of aquatic environments has only recently caught the attention of scientists, regulators and the public. Microplastics are typically more recalcitrant than naturally occurring polymers and so have the potential to cause a range of issues, including increased exposure of marine life to chemical contaminants sorbed to or leached from microplastics, negative impacts due to ingestion of microplastics by biota, and the potential to carry and transport pathogenic and invasive species long distances. Bio-based, bio-degradable polymers have begun to gain market share as an alternative to traditional petrochemical-based plastics, but not much is known about their impacts in marine environments. The overall objective of this thesis was to improve our understanding of how bio-based microplastics compare to petrochemical-based plastics in the marine environment. This information could be used to evaluate the overall sustainability of bio-based polymers as replacements for petrochemical-based polymers. The first chapter of this work investigated the potential of four types of microplastics, polyethylene (PE), polyvinyl chloride (PVC) and two bio-based polymers, poly-3-hydroxybutyrate (PHB) and polylactic acid (PLA), to sorb hydrophobic organic contaminants (pyrene, PCB-153, and BDE-47) from the surrounding water column. It also examined how co-exposure to several of these contaminants influenced their sorption. The bio-based polymers used in this work, exhibited lower affinity for the organic contaminants investigated compared to the more widely used, petrochemical-derived microplastics. This may be due to several factors including hydrophobicity of the plastic surfaces and the chemical structure of each plastic. Further, competition between several co-exposed contaminants led to an overall decrease in chemical partitioning on polyethylene microplastics. The second chapter reported on the microbial composition of biofilm communities that form on bio-based (PHB and PLA) and petrochemical-based (PE and PVC) microplastics in comparison to a naturally occurring polymer, chitin. Microbial compositions of biofilms that formed on the different plastics were similar during the first and second week of growth, but chitin exhibited a distinct community from the microplastics. By the fourth week of growth, all substrates had a similar community composition. Diversity was generally higher on bio-based plastics. Genera harboring marine pathogens and hydrocarbon-degrading bacteria were identified on all substrates. This work has implications to policy surrounding marine debris issues, exploring the more nuanced differences between bio-based polymers and petrochemical polymers, introducing concerns over additive use in bio-based polymers, and reinforcing the need for “eco-cyclable” materials in single-use items.

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19

CANENSI, SARA. "Census and Impact of Microplastics in the Deep-Sea Biosphere". Doctoral thesis, Università Politecnica delle Marche, 2019. http://hdl.handle.net/11566/263673.

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La plastica è uno dei principali contaminanti degli oceani del mondo che potrebbe danneggiare anche gli ecosistemi pelagici e bentonici profondi. Tuttavia, le informazioni sul suo impatto su comunità e habitat profonsi sono ancora molto frammentarie. In questa tesi di Dottorato, è stato sviluppato un protocollo specifico per l'estrazione di microplastiche (2-1000μm) da sedimenti di ambienti profondi. Questo è risultato molto efficace nel recupero delle microplastiche (60%), pertanto è stato applicato a diversi ecosistemi bentonici per valutare la rilevanza quantitativa e qualitativa delle microplastiche. I dati ottenuti mostrano che le microplastiche sono presenti in tutti gli habitat analizzati, con concentrazioni di microplastiche < 20 μm potenzialmente molto elevate. I canyon del Mediterraneo possono fungere in alcuni casi da sink di microplastiche facilitando il loro accumulo. Le comunità dei deep sea possono essere danneggiate dalla microplastica. Infatti, questa ricerca ha rivelato che i nematodi ingeriscono frammenti di polimeri come anche il Corallium rubrum. In particolare, gli esperimenti di mesocosmo su coralli rossi, esposti a diverse concentrazioni dei più comuni polimeri trovati in ambiente marino, hanno dimostrato che questi danneggiano diverse funzioni fisiologiche e molecolari fondamentali per la loro vitalità. La plastica nei deep sea può essere trasferita lungo le reti trofiche e/o colonizzata da comunità microbiche. In particolare, è stata osservata la presenza di famiglie batteriche esclusive della plastica su due tipi di polimeri raccolti nei canyon sottomarini, lasciando ipotizzare che tali famiglie potrebbero usare queste plastiche e rappresentare loro potenziali degradatori. I risultati ottenuti nella presente tesi di Dottorato espandono la nostra conoscenza sull' inquinamento da microplastiche negli ambienti profondi e forniscono nuovi spunti per l'attuazione di strategie di conservazione in tali habitat.
Plastics are among the main anthropogenic impacts of the world oceans. These are also expected to affect deep-sea pelagic and benthic ecosystems but information on microplastics impacts on deep-sea communities and habitats is still very fragmentary. In the framework of this PhD thesis, a protocol for extracting microplastics (2-1000μm) was specifically developed for deep-sea sediments. This protocol was very efficient to recovery microplastics (60%), thus was applied to different benthic deep-sea ecosystems to assess the quantitative and qualitative relevance of microplastics. The data obtained revealed that microplastics are widely present in all the deep-sea habitats, with potentially very high concentrations of microplastics with size lower than 20 μm. Mediterranean canyons can act as conduits for microplastics facilitating their accumulation in deep-sea sediments, although this is not always a general rule. Deep-sea communities can be impacted by microplastics contamination. Indeed, this research revealed that nematodes ingest microplastic fragments as well as Corallium rubrum colonies. In particular, the mesocosm experiments on red corals, exposed to different concentrations of the most common plastic polymers found in marine environment, showed that microplastics harm several physiological and molecular functions need for the maintenance of their vitality. Plastics in deep-sea sediments can be transfer across trophic webs and/or colonized by microbial communities. Here, we found that exclusive bacterial families (i.e., not found in the surrounding deep-sea sediments) can grow on two types of polymers collected in deep-sea canyons, leading to hypothesize that such families could use these plastics and represent their potential degraders. Findings obtained in the present PhD thesis add new insights into the knowledge of microplastics pollution in deep-sea ecosystems and provide new cues for implementing conservation strategies of deep-sea habitats.

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20

Rehse, Saskia [Verfasser]. "Effects of microplastics on freshwater organisms : A laboratory approach / Saskia Rehse". Tübingen : Universitätsbibliothek Tübingen, 2021. http://nbn-resolving.de/urn:nbn:de:bsz:21-dspace-944288.

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21

Wright, Stephanie. "The potential for microplastics to cause harm in the marine environment". Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18868.

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Plastic debris is an emerging environmental issue, with >10 million tons of plastics debris per annum entering the sea. Exposure to marine conditions facilitates the exponential fragmentation of plastic to micro-sized particles (microplastics). Marine and coastal sediments are a sink for microplastic pollution. Consequently, the ingestion of microplastics by a range of benthic marine invertebrates, including polychaete worms, has been reported in situ. Microplastics are vectors for priority pollutants capable of eliciting adverse health effects. However, the particle and chemical toxicity which microplastics could incur to ecologically-important marine invertebrates is unknown. This thesis aims to determine the potential for microplastics to cause harm in the marine environment, with a focus on benthic polychaete worms. Specifically, it assesses the potential particle toxicity which could arise from chemical-free microplastics; and the potential chemical toxicity which could arise from leached endogenous chemical additives or sorbed chemical pollutants. To address these, an integrative approach was employed, primarily using laboratory-based whole-sediment in vivo exposures, established cellular and whole-tissue toxicity assays, and analytical chemistry. For the first time, this thesis reports that chemical-free microplastics cause particle toxicity in the lugworm Arenicola marina. Feeding activity was reduced during exposure to 5% microscopic unplasticised polyvinylchloride (UPVC) by sediment weight, whilst exposure to ≥1% UPVC by sediment weight significantly reduced energy reserves relative to control animals. Evidence for the transfer and toxicity of endogenous additives from PVC to lugworms is provided. Lugworms exposed to 1% PVC by sediment weight exhibited a 70% increase in additive concentration, coinciding with inhibited mucus production and enhanced lipid reserves and oxygen consumption, compared to control lugworms. Ragworms (Hediste diversicolor) exposed to leached toxicants from bioplastic cigarette debris were found to exhibit significantly longer burrowing times, >30% weight loss, and >2-fold increase in DNA damage compared to control ragworms. Bio-concentration factors for nicotine – the biomarker of exposure - were 500 fold higher from leachates in seawater than from microfibres in sediment. Overall, this thesis provides evidence to suggest that the incorporation of microplastics into marine sediments can significantly impact the health of marine polychaete worms due to both particle and chemical effects. This emphasises the need to reconsider the classification of plastic as non-hazardous and questions whether we as humans are also at risk.

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22

Hanslik, Lisa [Verfasser] y Thomas [Akademischer Betreuer] Braunbeck. "Microplastics in Limnic Ecosystems - Investigation of Biological Fate and Effects of Microplastic Particles and Associated Contaminants in Zebrafish (Danio rerio)- / Lisa Hanslik ; Betreuer: Thomas Braunbeck". Heidelberg : Universitätsbibliothek Heidelberg, 2020. http://d-nb.info/1222517620/34.

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23

Birch, Quinn T. "Sources, Transport, Measurement and Impact of Nano and Microplastics in Urban Watersheds". University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1573575831771941.

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24

Overgaard, Emma. "Microplastics in the Gulf of Bothnia, SwedenA comparison between Österfjärden and Örefjärden". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-93418.

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Microplastics are emerging pollutants in the marine environment, including a range of polymers modified by varying quantities of additives and sorbed pollutants, differing in size, colour, and shape. This study focuses on characterization and quantification through visual characterization of microplastics >300 μm in surface water and at 5-meter depth in the Gulf of Bothnia. A comparison between a reference area and an urban impact area was made to estimate if the water is more polluted near rural or industrial areas. The visual characterization was based on general guidelines provided by GESAMP to minimize the risks of identifying false positives. The concentrations of microplastics were found to be similar in the current study in comparison to other studies in the Baltic Sea. There was insufficient evidence to conclude a difference between the reference area and the urban impact area. A key finding in this study was that fragments, i.e. irregular shaped hard particles having appearance of being broken down from a larger piece of litter were the most abundant type of microplastics particles found. The vast majority of the identified polymers by ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy) consisted of Polyethylene (PE) and Polystyrene (PS)

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25

Fortin, Samantha Grace. "Estuarine Microbiomes And Biogeochemistry: Impacts Of Spatiotemporal Variation, Algal Blooms, And Microplastics". W&M ScholarWorks, 2021. https://scholarworks.wm.edu/etd/1627407480.

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Estuaries are biogeochemical hotspots connecting terrestrial and coastal ecosystems. Anthropogenic disturbances, including increased nitrogen loading and plastic pollution, may have significant impacts on estuarine carbon and nitrogen cycling by altering microbiome structure and functions. The overarching goal of this dissertation was to examine how microbiomes and their associated biogeochemical processes are influenced by natural variation and anthropogenic disturbances in the York River Estuary (YRE). In chapter 2, spatial and temporal variation in benthic microbiomes and the rates of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were examined to determine biotic and abiotic drivers of nitrogen removal and retention. In the YRE, nitrogen removal, largely in the form of denitrification, dominated at the head of the estuary while nitrogen retention through DNRA dominated at the mouth. Denitrification was linked to a large community of denitrifying organisms, sediment organic matter, nitrate/nitrite concentrations, salinity, and chlorophyll a, while DNRA was best predicted by the abundance of specific taxa, Desulfobacterales and Sphingobacteriales, as well as temperature and the concentration of ammonium. The impacts of the harmful algal blooms of Margalefidinium polykrikoides and Alexandrium monilatum that occur in the lower portion of the estuary were examined in Chapter 3. Blooms of both species altered the water column microbiome of the YRE. The M. polykrikoides bloom, with its higher concentration of dissolved organic carbon and close associations with heterotrophic bacteria, likely has a greater impact on the estuarine carbon cycle than the A. monilatum bloom. The A. monilatum bloom did not impact the overall prokaryotic community, but appeared to selectively enhance a small group of prokaryotes in the particle-associated fraction. Chapters 4 and 5 investigated plastic pollution in the YRE. A method was developed to isolate, quantify, and identify the polymer type of plastic particles in wastewater treatment plant effluents using Raman microspectroscopy (chapter 4); microplastic particles composed of polyethylene were found to be the most common. Microplastics composed of polyethylene, polyvinyl chloride, and polylactic acid were deployed to the YRE and the microbial biofilm communities growing on each type of plastic were examined over time to determine their taxonomic and functional profiles (chapter 5). All three microplastic types were found to contain potential hydrocarbon degrading bacteria, as well as nitrogen cycling bacteria capable of performing nitrification, denitrification, and DNRA. Overall, this dissertation investigated how microbially mediated nitrogen cycling processes can remove or retain fixed nitrogen, how algal blooms can change an estuary’s microbiome, and how the addition of microplastic pollution can provide new habitat for microbes that can perform nitrogen cycling and hydrocarbon degradation in the water column.

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26

Adner, Johanna. "Exploring the Outdoors : mapping microplastics in the textile design- and production processes". Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-22087.

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Microplastics have been found in all aquatic environments and once they entered they cannot be removed. This has put new focus on the sources of microplastics where the textile industry has gained large attention. Much consideration has been given to the production of fleece fabric and the use of polyester but this report aims to explore the whole design- and production process and mapping those activities which has a large impact on microplastic release. Together with participants from five (5) Swedish Outdoor Brands and seven (7) field experts has this report mapped possible challenges and solutions. Main findings are 20 different challenging areas with 19 suggested solutions on how to prevent microplastic pollution. The result is the first in its kind doing a comprehensive study of the whole textile design- and production process and provides a broad foundation for further research. As there still is a considerable lack of knowledge about many of the issues that were brought up, both within the design- and production processes, has a shared responsibility among companies, organizations, universities and private persons been raised. Through common platforms are inspiration and awareness spread and this report aims to contribute to the gap in the current knowledge.

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27

RANI, MONIKA. "Analysis and Characterization of Microplastics through Vibrational Spectroscopic Techniques for Environmental Monitoring". Doctoral thesis, Università degli studi di Brescia, 2022. http://hdl.handle.net/11379/563081.

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The pinnacle of technological advancements, especially plastic, has become one of the greatest environmental challenges that the earth has ever dealt with. In the face of ground-breaking versatility, plastic litter has marked its presence from the highest peaks to the deepest points in the oceans. Microplastics (MPs) are plastic particles with a size of less than 1 mm along their longest dimension, originating from a wide array of sources. The current public awareness of MP pollution is based on a huge amount of scientific research completed and published over the last fifteen years, which has just recently been highlighted by the media. It's been a protracted process that began with isolated examinations carried out by researchers who were ordinarily working in various fields of study but recognised the threat's potential. MPs are not traditional chemical contaminants, but rather a complex array of manmade detritus made up of various sizes, polymers, chemical additives, and sorbed pollution. The MP study is still in its infancy stage since it continues to be hampered by a lack of defined protocols and methodologies for investigating MPs in the laboratory. The use of MPs in laboratory research necessitates precise particle characterization to link the impacts of microplastics to their characteristics. To understand microplastic transit, deposition, and toxic effects, it is vital to distinguish between MP particles and those that are not. This thesis has primarily focused on the application of a new technology for analyzing MPs, based on Near-Infrared Spectroscopy (NIRs). As revealed by the bibliometric analysis of characterizing MPs by Fourier-Transformation Infrared Spectroscopy (FTIR) and Near-Infrared Spectroscopy, NIRs have only lately been applied, notably in the form of the miniaturized spectrometer (NIRs). Although NIR spectroscopy has been used as a standard tool for online quality assurance in food manufacturing and pharmaceuticals for decades, its ability to analyse microplastics in various environmental matrices has only recently been recognized. The workflow of this thesis begins with the use of handheld MicroNIR to analyse urban plastic garbage and construct an in-house NIR spectrum library, showcasing the usage of portable technology in the recycling sector. Because most libraries are constructed with virgin polymers, spectral shifts caused by MPs degradation are frequently missed. As a result, a new, more durable library searching algorithm capable of dealing with the difficulty of comparing degraded MPs to pristine polymer references was necessary. The second section discussed the significance of using reference materials in MP research and compares three techniques for producing MPs for research laboratories. This work will make it easier to comprehend the morphologies of MPs produced from the same parent particle using diverse techniques in a short period, allowing MP research to accelerate. The third section is based on the proof-of-concept study to analyse mixtures of microplastics through a handheld Near-Infrared Spectrometer. Given that, this study has proven the possibility of a portable tiny near-infrared spectrometer (MicroNIR) paired with chemometric methodologies for the measurement of secondary MPs mixes created at a laboratory scale for the first time. Extraction and purification are followed by identification and quantification in the MP analysis. The extraction of MPs from any environmental matrix is the most important phase since it is controlled by the matrix type and microplastic's size, shape, and density. As a result, the extraction technique should be tailored to the type of matrix under consideration. Following this idea, a comprehensive description of microplastic extraction processes distinguished by environmental matrix is offered at the end of this thesis in the form of a review. With concluding remarks, the final chapter gives a glimpse into the study's future prospects.
The pinnacle of technological advancements, especially plastic, has become one of the greatest environmental challenges that the earth has ever dealt with. In the face of ground-breaking versatility, plastic litter has marked its presence from the highest peaks to the deepest points in the oceans. Microplastics (MPs) are plastic particles with a size of less than 1 mm along their longest dimension, originating from a wide array of sources. The current public awareness of MP pollution is based on a huge amount of scientific research completed and published over the last fifteen years, which has just recently been highlighted by the media. It's been a protracted process that began with isolated examinations carried out by researchers who were ordinarily working in various fields of study but recognised the threat's potential. MPs are not traditional chemical contaminants, but rather a complex array of manmade detritus made up of various sizes, polymers, chemical additives, and sorbed pollution. The MP study is still in its infancy stage since it continues to be hampered by a lack of defined protocols and methodologies for investigating MPs in the laboratory. The use of MPs in laboratory research necessitates precise particle characterization to link the impacts of microplastics to their characteristics. To understand microplastic transit, deposition, and toxic effects, it is vital to distinguish between MP particles and those that are not. This thesis has primarily focused on the application of a new technology for analyzing MPs, based on Near-Infrared Spectroscopy (NIRs). As revealed by the bibliometric analysis of characterizing MPs by Fourier-Transformation Infrared Spectroscopy (FTIR) and Near-Infrared Spectroscopy, NIRs have only lately been applied, notably in the form of the miniaturized spectrometer (NIRs). Although NIR spectroscopy has been used as a standard tool for online quality assurance in food manufacturing and pharmaceuticals for decades, its ability to analyse microplastics in various environmental matrices has only recently been recognized. The workflow of this thesis begins with the use of handheld MicroNIR to analyse urban plastic garbage and construct an in-house NIR spectrum library, showcasing the usage of portable technology in the recycling sector. Because most libraries are constructed with virgin polymers, spectral shifts caused by MPs degradation are frequently missed. As a result, a new, more durable library searching algorithm capable of dealing with the difficulty of comparing degraded MPs to pristine polymer references was necessary. The second section discussed the significance of using reference materials in MP research and compares three techniques for producing MPs for research laboratories. This work will make it easier to comprehend the morphologies of MPs produced from the same parent particle using diverse techniques in a short period, allowing MP research to accelerate. The third section is based on the proof-of-concept study to analyse mixtures of microplastics through a handheld Near-Infrared Spectrometer. Given that, this study has proven the possibility of a portable tiny near-infrared spectrometer (MicroNIR) paired with chemometric methodologies for the measurement of secondary MPs mixes created at a laboratory scale for the first time. Extraction and purification are followed by identification and quantification in the MP analysis. The extraction of MPs from any environmental matrix is the most important phase since it is controlled by the matrix type and microplastic's size, shape, and density. As a result, the extraction technique should be tailored to the type of matrix under consideration. Following this idea, a comprehensive description of microplastic extraction processes distinguished by environmental matrix is offered at the end of this thesis in the form of a review. With concluding remarks, the final chapter gives a glimpse into the study's future prospects.

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28

Dawson, Amanda. "Uptake dynamics and effects of traditional and emerging persistent environmental pollutants to the Antarctic keystone species, Antarctic krill". Thesis, Griffith University, 2017. http://hdl.handle.net/10072/373031.

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The schooling Euphausiid, Antarctic krill (Euphausia superba) is considered a keystone species in the Southern Ocean due to its abundance, prominent role in nutrient cycling, and dependency of almost all Antarctic predatory species on this single species. It has often been postulated that polar species may be more sensitive to anthropogenic contaminants on account of their evolutionary isolation from exposure. Despite geographical isolation, anthropogenic contaminants have frequently been detected in the Southern Ocean and Antarctica biota, including, heavy metals, petroleum products, persistent organics pollutants (POPs) as well as microplastic (plastics <5 mm diameter) marine debris. This thesis examined the response of Antarctic krill exposed to two common pollutants; the POP compound para, para-Dichlorodiphenyldichloroethylene (p,p’-DDE), a metabolic by-product of the pesticide Dichlorodiphenyltrichloroethane (DDT); and polyethylene (PE) microplastics. To investigate the fate of microplastics ingested by a grazing crustacean of high dietary plasticity, commercial microplastic PE beads were offered to Antarctic krill as a proportion of their diet. Krill were exposed to either a low (20%) or high (80%) dose plastic diet for four days, after which the faecal pellets and internal body burdens were examined. Antarctic krill were found to mechanically alter ingested microplastic beads into irregular fragments and nanoplastics. The capacity for fragmentation was found to be dependent on the concentration ingested. Further, the krill displayed size dependant depuration of the altered beads. This is the first time pristine microbeads have been noted to be physically altered by ingestion. With regards to the fate of commercial PE beads ingested by Antarctic krill, it appears that larger microplastics are fragmented into pieces that are small enough to cross biological barriers after ingestion, or are egested as a mixture of irregular triturated particles. These findings suggest that the current literature, based on observations from laboratory-based feeding studies, may be oversimplifying the way in which zooplankton interact with microplastics. To investigate the uptake and depuration kinetics, bioaccumulation potential and detrimental health effects of irregular triturated microplastics Antarctic krill were exposed to commercial microplastic PE beads in a range of concentrations (10, 20, 40 and 80% plastic mixed diet). Toxicological endpoints of mortality and weight loss were both found to be non-sensitive for acute exposure in Antarctic krill. The depuration of particles large enough to be detected was found to be extremely fast, with krill eliminating 80% of their accumulated body burden in a matter of hours. Effective depuration was proposed to be the primary mechanism for mitigation of bioaccumulation and toxicity in krill, with bioaccumulation over 10 days of exposure found to be negligible. However, as uptake rates were similarly fast, and organisms in the marine environment are unlikely to experience microplastic free conditions to depurate their accumulated burden, chronic exposure over the lifetime of the organism with a continuous, yet variable, uptake and egestion is suggested to be a more likely scenario. Further, particles small enough to cross biological barriers were not quantified in this study, and the bioaccumulation potential of these particles remains to be evaluated. To investigate sublethal p,p’-DDE exposure and identify potential biomarkers of sub cellular damage Antarctic krill were aqueously exposed to five treatments (1, 5, 10, 15 and 20 μg L-1) of p,p’-DDE. The response of enzymes with known roles in exogenous compound metabolism (glutathione S-transferase, GST and cytochrome P450 2B, CYP2B), neurotoxicity (acetylcholinesterase, AChE) and oxidative stress (glutathione peroxidase GPx) were quantified. CYP2B was not detectable in Antarctic krill. None of the enzymes detected induced linear concentration-dependant responses. GST was elevated at all exposure concentrations compared to the control, however no treatments were significantly different. GPx and GST followed similar trends throughout the treatment responses suggesting that an underlying biological factor may be influencing both enzymes. AChE activity was not correlated with p,p’-DDE exposure concentration, but all concentrations displayed lower activity than the solvent control however no treatment was significantly inhibited by p,p’-DDE in Antarctic krill. These findings did not provide evidence for an activated detoxification response to p,p’-DDE via the targeted biochemical pathways in Antarctic krill. These findings provide an important baseline for future work to establish the mechanisms of organochlorine toxicity and further our understanding of Antarctic krill detoxification capabilities. Overall, the results of the work described in this thesis characterise several key interactions between anthropogenic pollutants and Antarctic krill. This work provides a comprehensive foundation for further investigation on the combined effect of p,p’-DDE and polyethylene microplastic stressors, as well as other microplastics and POPs in isolation and as mixtures, which may better reflect environmental conditions.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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29

Scapinello, Sara. "Characterization of microplastics ingested by marine benthos - a methodological and field-experimental study". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14696/.

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Microplastics have become ubiquitous pollutants in the marine environment. Ingestion of microplastics by a wide range of marine organisms has been recorded both in laboratory and field studies. Despite growing concern for microplastics, few studies have evaluated their concentrations and distribution in wild populations. Further, there is a need to identify cost-effective standardized methodologies for microplastics extraction and analysis in organisms. In this thesis I present: (i) the results of a multi-scale field sampling to quantify and characterize microplastics occurrence and distribution in 4 benthic marine invertebrates from saltmarshes along the North Adriatic Italian coastal lagoons; (ii) a comparison of the effects and cost-effectiveness of two extraction protocols for microplastics isolation on microfibers and on wild collected organisms; (iii) the development of a novel field- based technique to quantify and characterize the microplastic uptake rates of wild and farmed populations of mussels (Mytilus galloprovincialis) through the analysis of their biodeposits. I found very low and patchy amounts of microplastics in the gastrointestinal tracts of sampled organisms. The omnivorous crab Carcinus aestuarii was the species with the highest amounts of microplastics, but there was a notable variation among individuals. There were no substantial differences between enzymatic and alkaline extraction methods. However, the alkaline extraction was quicker and cheaper. Biodeposit traps proved to be an effective method to estimate mussel ingestion rates. However their performance differed significantly among sites, suggesting that the method, as currently designed, is sensible to local environmental conditions. There were no differences in the ingestion rates of microplastics between farmed and wild mussels. The estimates of microplastic ingestion and the validated procedures for their extraction provide a strong basis for future work on microplastic pollution.

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30

Schirinzi, Gabriella Francesca. "Chemical and ecotoxicological assessment of microplastics and emerging risks in the coastal environments". Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/669139.

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In recent decades, global plastics production and consumption have continued to increase. Although many policy strategies on waste prevention and recycling have been implemented, much of the plastic waste is dispersed in nature. In general, the presence of waste in the aquatic environment is a serious environmental problem, well known as marine waste, and is responsible for environmental, economic, health and aesthetic problems at the ocean and regional level and the dominant category of waste is plastics. Due to their chemical persistence, buoyancy and increased sources, plastic objects and their fragments (known as "microplastics" (MPLs) and "nanoplastics" (NPLs)) are omnipresent in the marine environment, especially in closed basins such as the Mediterranean Sea. Nowadays, given the increasing levels of plastic pollution in marine environments, MPL/NPL are considered emerging pollutants that can pose a serious threat to marine ecology and human health. Despite constant scientific progress, large gaps in knowledge about the fate, distribution, behaviour and effects of MPLs/NPLs have not yet been filled. In this context, this thesis aimed to expand knowledge on plastic pollution in coastal environments. In particular, the first part of the study focused on the river transport of plastics and the fate and behaviour of MPLs/NPLs in estuaries and coastal waters. The results of one year of visual observations of floating anthropogenic macro-litters (> 2.5 cm) of the Llobregat and Besòs Rivers showed that the Barcelona metropolitan area contributes substantially to marine pollution. Large quantities of plastic (mainly single-use goods) were transported from these rivers to the western Mediterranean Sea. Given the significant contribution of plastic waste from rivers, valuable information can be obtained by assessing the spatial distribution of MPLs/NPLs in estuarine environments. To perform these studies, several analytical techniques based on mass spectrometry (MALDI-TOF/MS, DART-MS, and LC-APPI-HRMS) were compared for the quantitative analysis of MPLs/NPLs in water samples. The best results in terms of sensitivity were obtained with dimensional exclusion-LC coupled with APPI-QExactive. Consequently, a new LC-HRMS method was optimized, validated and finally applied to assess the presence of PS in natural water samples from the Ebro Delta (Catalonia, Spain). The results reported the highest concentrations along the river near urban areas and in the bay where important commercial fishing activities are established. In addition to plastic pollution, estuaries can be highly contaminated with persistent organic pollutants, especially from wastewater. Since MPLs may also be responsible for the transport and distribution of pollutants, the absorption behaviour of MPLs with perfluoroalkylated substances (PFASs) in freshwater and seawater has been assessed. An increase in adsorption capacity was observed in this order PS>PS-COOH>PE. As demonstrated by these results, the plastic pollution of coastal ecosystems, from macro to nano, is a real problem that can lead to serious damage to both nature and society. To protect the coastal environment, its productivity and humans, it is necessary to assess the ecotoxicological impacts on marine organisms and human health. In this regard, a new digestion approach has been developed to determine the presence of MPLs in the gastrointestinal tracts of a sentinel species in the Western Mediterranean. The high frequency of plastics and the types of polymers reported in this study confirmed the negative impacts of local fishing gear. Although the ingestion of MPLs by marine organisms is a widely recognised effect of marine plastic waste, very limited data are available on the impact of MPLs, and especially NPLs, on human health. Therefore, cytotoxic effects at the cellular level after exposure to moderate concentrations of PS and PE particles of nanometric size have been assessed. Significant results were reported only at high concentrations of PS. In conclusion, the work presented in this thesis has successfully filled some of the various gaps in knowledge about plastic pollution and its effects. In the future, further tools should be promoted to facilitate the overall analysis of smaller MPLs, including NPLs.
Los plásticos han desempeñado un papel importante en el desarrollo tecnológico e industrial, mejorando la calidad de la vida humana, pero, el uso excesivo y mala gestión de los desechos han dado lugar a la acumulación de residuos plásticos en el medio ambiente. Debido a su persistencia, los desechos plásticos se encuentran presentes en diferentes compartimentos ambientales como ya ha sido señalado en varios estudios, donde la mayor preocupación se centra en las partículas de tamaño más pequeño. Hoy en día, los micro(nano)plásticos se consideran contaminantes peligrosos que pueden causar graves daños al medio ambiente y la salud humana. Es por ello que se debe profundizar en la evaluación química y ecotoxicológica de los micro(nano)plásticos y los riesgos emergentes. La investigación científica ha promovido numerosas iniciativas para evaluar la presencia, destino e impacto ambiental de estos contaminantes en el medio acuático, especialmente en los medios marinos. En este contexto, los objetivos generales de esta tesis doctoral se enfocaron en estudios integrados de la presencia y destino de la contaminación plástica en el medio ambiente costero, especialmente en el transporte fluvial de macroplásticos en la zona de Barcelona y el destino/comportamiento de las micro(nano)partículas de plástico en las aguas estuarinas y costeras del noroeste del Mar Mediterráneo. Para ello, se desarrollaron métodos analíticos para cuantificar e identificar el comportamiento de estos compuestos y sus co-contaminantes en el medio ambiente. Los resultados demostraron una contribución significativa de desechos plásticos provenientes de los ríos. En particular, para el análisis de micro(nano)plásticos en agua, se desarrolló un método con exclusión dimensional-LC acoplada con APPI-QExactive que permitió cuantificar la presencia de poliestireno (PS) en muestras de agua del Delta del Ebro (Cataluña, España). Posteriormente, se realizó un estudio de adsorción de sustancias perfluoroalquiladas en la superficie de los microplásticos donde se observó un aumento de la capacidad de adsorción de PS>PS-COOH> polietileno. Por último, se evaluaron las consecuencias ecotoxicológicas de los micro(nano)plásticos en el medio ambiente y la salud humana. Se confirmó una alta frecuencia de plásticos en una especie centinela del Mediterráneo, producto de los aparejos de pesca locales. Finalmente, los efectos citotóxicos de los PS-nanoplásticos han sido comprobados por estudios toxicológicos en células humanas.

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OLIVATTO, GLAUCIA PEREGRINA. "STUDY ABOUT MICROPLASTICS IN SURFACE WATERS IN THE WESTERN PORTION OF GUANABARA BAY". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29926@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
AGÊNCIA NACIONAL DE PETRÓLEO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Partículas de plásticos com tamanho inferior a 5 milímetros, denominadas microplásticos, estão entre os contaminantes que ameaçam o ambiente marinho. A presença de microplásticos em suspensão na coluna d água é motivo de grande preocupação, devido à sua ampla distribuição, capacidade de adsorção e dispersão de contaminantes orgânicos e potencial de ingestão por organismos na base da cadeia trófica. Nesse contexto, o objetivo central deste estudo foi avaliar a ocorrência desses resíduos nas águas superficiais na porção oeste da Baía de Guanabara, através da determinação de sua composição qualitativa e quantitativa. Amostras de microplásticos foram coletadas em três campanhas no verão de 2016, através do arrasto horizontal com rede de 330 micrômetros em três diferentes áreas potencialmente afetadas por plásticos. As partículas menores que 5 milímetros foram isoladas por peneiramento via úmida, triadas com o auxílio de uma lupa binocular e classificadas de acordo com a sua forma, cor e tamanho. A quantidade de microplásticos foi determinada por gravimetria, contagem manual e processamento digital de imagens, obtidas por microscopia óptica. O tipo de polímero em cada categoria foi determinado por espectroscopia de absorção no infravermelho médio (FT-IR) com refletância total atenuada (ATR). Os resultados obtidos, considerando-se as três campanhas, indicam que os polímeros mais representativos foram polietileno e polipropileno correspondendo, respectivamente, a 71,5 mais ou menos 8,1 por cento e 23,8 mais ou menos 5,8 por cento do total analisado. Partículas inferiores a 1 milímetro foram as mais abundantes com média de 34,0 mais ou menos 9,6 por cento. Os plásticos classificados como fragmentos e filmes foram os mais encontrados representando, respectivamente, os valores médios de 44,3 mais ou menos 9,3 por cento e 33,7 mais ou menos 10,1 por cento. Microplásticos coloridos foram os predominantes, apresentando valores acima de 40,0 por cento. Os resultados obtidos comprovam a ocorrência de microplásticos nas águas superficiais da Baía de Guanabara, indicando que a falta de manejo de resíduos sólidos em sua bacia de drenagem contribui com esse panorama, sendo esse, portanto mais um problema ambiental a ser investigado.
Plastics particles smaller than 5 millimeter, known collectively as microplastics, are among the hazardous contaminants that threaten the marine environment. Microplastics suspended in the water column are of concern because of its widespread distribution and potential to carry on adsorbed contaminants in a global scale as well the and potential ingestion by organisms at the base of the trophic chain. In this context, the main objective of this study was to evaluate the occurrence of such wastes on surface waters of the western portion of Guanabara Bay, by determining their qualitative and quantitative composition. Microplastics samples were collected in three campaigns in the summer of 2016, through horizontal drag with 330 micrometers net in three different areas potentially affected by plastics. Particles smaller than 5 millimeter were isolated by wet sieving, screened with the aid of an ocular magnifier and classified according to their shape, color and size. The amount of microplastics was determined by gravimetry, manual counting and digital images processing, obtained by light microscopy. The type of polymer in each category was determined by absorption spectroscopy of mid infrared (FT-IR) with attenuated total reflectance (ATR). The results obtained, considering the three campaigns, indicate that the most representative polymers were polyethylene and polypropylene corresponding, respectively, to the mean values of 71.5 more or less 8.1 per cent and 23.8 more or less 5.8 per cent. Particles smaller than 1 mm were the most abundant indicating the mean of 34.0 more or less 9.6 per cent. Plastics classified as fragments and films were the most found representing, respectively, the mean values of 44.3 more or less 9.3 per cent e 33.7 more or less 10.1 per cent. Colored microplastics were the predominant, ones presenting values above 40.0 per cent. The results obtained confirm the occurrence of microplastics in the surface waters of Guanabara Bay, indicating that the lack of solid waste management in its drainage basin contributes to this scenario, which is therefore an environmental problem to be investigated.

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Harrison, Jesse P. "The spectroscopic detection and bacterial colonisation of synthetic microplastics in coastal marine sediments". Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2643/.

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Synthetic microplastics (≤5-mm fragments) are anthropogenic contaminants that are rapidly accumulating in coastal environments worldwide. The distribution, abundance, ecological impacts and fate of these pollutants are poorly understood. In this study, a novel reflectance micro-FT-IR spectroscopy method was developed to detect microplastics in sediments from 17 sites (UK), using polyethylene (PE) as the model polymer. Additionally, a 14-day laboratory microcosm experiment was used to characterise bacterial succession on low-density polyethylene (LDPE) fragments over time and across three sediment types (ranging from sand to silt) from the Humber Estuary, UK. In contrast with ATR-FT-IR measurements, micro-FT-IR measurements in reflectance mode were susceptible to refractive error when analysing irregularly shaped PE fragments. However, molecular mapping by reflectance micro-FT-IR spectroscopy successfully detected PE within polymer-spiked sediments and in a non-spiked sediment retentate. Moreover, reflectance micro-FT-IR spectra of PE were consistent across all 17 sampling sites. Bacteria were found to rapidly colonise LDPE fragments, with bacterial community structure and diversity differing significantly from those in bulk sediments, as demonstrated by scanning electron microscopy, T-RFLP analysis and 16S rRNA gene sequencing. The composition of LDPE-colonising assemblages within different sediment types increasingly converged over time, with 16S rRNA gene sequencing analysis identifying site-specific populations of the genera Arcobacter (Epsilonproteobacteria) and Colwellia (Gammaproteobacteria) as dominant members (up to 93% of sequences) of the plastic-associated communities after 14 days of exposure. Log-fold increases in the relative abundance of LDPE-associated bacteria occurred within 7 days of exposure with bacterial abundance differing significantly across sediment types, as shown by Q-PCR amplification of 16S rRNA genes. Attachment of bacterial cells and specifically of Colwellia spp. onto LDPE surfaces was demonstrated by CARD-FISH analysis. These results provide a foundation to both developing improved spectroscopy methods to detect microplastics, and characterising ecological interactions between microorganisms and microplastic debris within marine sediments.

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Al-Ghorabi, Marianne. "Enhancing the degradation rate of microplastics and organizing a study visit about sustainability". Thesis, KTH, Lärande, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-272078.

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Microplastics take hundreds to thousands of years to degrade in nature, and pose a threat to the environment. A photocatalytical degradation method have been developed to take advantage of solar light to degrade microplastics, however it takes several months to degrade microplastics with the process. The purpose of this study is to enhance the degradation rate of microplastics by synthesizing a material where photocatalysis is combined with Fenton reaction. A material with zinc oxide nanorods coated with tin oxide and decorated with iron particles (𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0) was synthesized and used to degrade methylene blue, polystyrene and polypropylene. The result show that the degradation rate with a 𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0 – sample is faster than with a 𝑍𝑛𝑂 – sample, and that it can be used to degrade polystyrene and polypropylene.Students’ view on researchers can affect the development of their interest and attitude towards science. Study visits to laboratories have been used to increase students’ interest and give them new experiences. The purpose of this study is to investigate what and how high school students learn during a study visit to a nanotechnology laboratory, and how the study visit affects high school students’ interest and motivation for research and learning. A study visit with 5 stations was organized, and students were given a questionnaire about what they learned during the study visit. Thematic analysis was used to analyze the students’ answers. The result shows that the study visit increased students’ interest in research, and the importance of designing stations so that they are connected to students’ previous knowledge and are within their proximal development zone.
Mikroplaster tar hundratals till tusentals år att bryta ner i naturen och utgör ett hot mot miljön. En fotokatalytisk nedbrytningsprocess har utvecklats där solljus utnyttjas för att bryta ner mikroplaster, dock tar det flera månader att bryta ner mikroplaster med den processen. Syftet med denna studie är att förbättra nedbrytningshastigheten av mikroplaster genom att syntetisera ett material där fotokatalys kombineras med Fenton-reaktion. Ett material med zinkoxid nanorör belagda med tennoxid och dekorerade med järnpartiklar (𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0) syntetiserades och användes för att bryta ner metylenblått, polystyren och polypropen. Resultatet visar att nedbrytningshastigheten med 𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0 – materialet är snabbare än med ett 𝑍𝑛𝑂 – material, och att 𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0 – materialet kan användas för att bryta ned polystyren och polypropen.Elevers syn på forskning och forskare kan påverka utvecklingen av deras intresse och inställning till vetenskap. Studiebesök på laboratorier har använts för att öka elevernas intresse och ge dem nya erfarenheter. Syftet med denna studie är att undersöka vad och hur gymnasieelever lär sig under ett studiebesök i ett nanotekniklaboratorium och hur studiebesöket påverkar gymnasieelevernas intresse och motivation för forskning och lärande. Ett studiebesök med 5 stationer organiserades och eleverna fick ett frågeformulär om vad de lärde sig under studiebesöket. Tematisk analys användes för att analysera elevernas svar. Resultatet visar att studiebesöket ökade elevernas intresse för forskning och vikten av att utforma stationer så att de är kopplade till elevernas tidigare kunskaper och ligger inom deras proximala utvecklingszon.

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Kazour, Maria. "Active and passive biomonitoring tools for microplastics assessment in two highly polluted aquatic environments : case study of the Seine estuary and the Lebanese coast SOURCES OF MICROPLASTICS POLLUTION IN THE MARINE ENVIRONMENT: IMPORTANCE OF WASTEWATER TREATMENT PLANT AND COASTAL LANDFILL MICROPLASTICS POLLUTION ALONG THE LEBANESE COAST (EASTERN MEDITERRANEAN BASIN): OCCURRENCE IN SURFACE WATER, SEDIMENTS AND BIOTA SAMPLES JUVENILE FISH CAGING AS A TOOL FOR ASSESSING MICROPLASTICS CONTAMINATION IN ESTUARINE FISH NURSERY GROUNDS IS BLUE MUSSEL CAGING AN EFFICIENT METHOD FOR MONITORING ENVIRONMENTAL MICROPLASTICS POLLUTION?" Thesis, Littoral, 2019. http://www.theses.fr/2019DUNK0544.

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La production de plastique est en augmentation continue pour répondre à la forte demande mondiale. Cette production massive est la source d'importantes quantités de plastiques que l'on retrouve dans les milieux aquatiques. Parmi ces plastiques, les microplastiques (MP) (particules microscopiques d’une taille < 5 mm) se retrouvent dans l’eau, les sédiments et sont susceptibles d’être ingérés par divers organismes marins. Cette thèse se focalise sur (1) l’évaluation des sources et des apports de microplastiques au milieu aquatique et de leur présence dans les organismes, et (2) de tester la faisabilité d’utiliser des organismes vivants pour la surveillance de la pollution de l’environnement par les microplastiques. Deux zones côtières affectées par des pressions anthropogéniques ont été étudiées : Le Havre et le littoral libanais. Dans le premier cas, le rôle d’une station de traitement des eaux usées (STEP) et d’une décharge côtière dans l’introduction des microplastiques dans l’environnement a été étudié. Les MPs ont d’abord été analysés dans l'influent, la boue et l’effluent de la STEP. Leur devenir a été suivi selon un gradient de distance de la STEP au niveau de trois matrices : eau de surface, sédiments et moules sauvages (Mytilus spp.). Les MPs ont été trouvés au niveau de toutes les matrices avec une concentration qui diminue en s’éloignant de l’effluent. Des taux de microplastiques élevés (plus élevés que ceux trouvés à côté de la STEP) ont été observés à proximité de la décharge côtière, suggérant son rôle important comme voie d’entrée des MPs dans les eaux côtières. Le long de la côte libanaise, nous avons évalué pour la première fois la pollution par les MPs dans l'eau de mer, les sédiments et dans deux espèces marines importantes en terme de consommation humaine (un poisson pélagique: Engraulis encrasicolus et un bivalve: Spondylus spinosus). Les résultats ont montré différents patterns de concentration des MPs dans les matrices analysées. La présence de MPs dans les organismes était élevée (83.4% et 86.3% dans les anchois et les huîtres, respectivement). Ces résultats ont mis en évidence la pollution élevée liée aux MPs au niveau du bassin Levantin par rapport aux autres régions de la Méditerranée occidentale. De plus, les résultats obtenus indiquent une contribution potentielle des décharges côtières à cette pollution. Le plus souvent, les études sur les microplastiques impliquent l'échantillonnage d’organismes indigènes. Au cours de cette thèse, nous avons testé la faisabilité d'utiliser des organismes transplantés (encagement) pour évaluer la pollution par les microplastiques dans l'environnement marin côtier. Nous avons mis au point des expériences d'encagement avec des juvéniles de flets, Platichthys flesus, en estuaires et des moules bleues, Mytilus edulis, en zone côtière. Pour chaque espèce, l'abondance et les caractéristiques (forme, taille, couleur et type de polymères) des MPs ingérés par les individus encagés ont été comparées avec les MPs ingérés par des individus sauvages capturés sur le même site et avec ceux trouvés dans leur environnement (eaux de surface et sédiments). Nos résultats suggèrent que la technique d'encagement d'organismes peut constituer un outil prometteur pour la biosurveillance des MPs la rendant plus fiable et permettant une étude précise des effets biologiques des MPs sur une période d'exposition prédéterminée
Plastic fabrication is increasing worldwide in response to daily human demands. This mass production is linked to the immense plastic marine litter found all around the world: each synthetic material is meant to find its way back into the aquatic systems. Anthropogenic pressure and the immense human population, the lack of appropriate plastic treatment process and the growing industrial activities advocate their presence in the aquatic environments. These plastics are then found in the form of microplastics (microscopic particle with a size < 5 mm) observed in the water, in the sediments and are prone to be ingested by various marine organisms along the trophic chain. This thesis focuses on (1) assessing microplastics sources and input into the aquatic environment and their occurrence in biota, and (2) to test the feasibility of using transplanted organisms (caging) for monitoring microplastics pollution in the marine coastal environment. Two coastal areas highly impacted by anthropogenic pressures were studied: Le Havre in France and the Lebanese coast. For the former, the role of a municipal wastewater treatment plant (WWTP) effluent and an abandoned coastal landfill as pathways for microplastics (MPs) input into the marine environment was assessed. MPs were first analyzed in raw sewage influent, sludge and effluent samples, and their fate was studied along a distance gradient from the WWTP in three matrices: surface water, sediments and wild mussels (Mytilus spp). MPs were found in all matrices with a decreasing abundance from the effluent. Strong MPs abundances (higher than those found near the WWTP effluent) were observed in the vicinity of the coastal landfill suggesting its importance as a MPs entry route into the marine coastal environment. Whereas for the Lebanese coast, we evaluated for the first time the MPs pollution in the seawater, sediments and two important seafood species (one pelagic fish: Engraulis encrasicolus and one bivalve: Spondylus spinosus). Results showed different patterns of MPs concentration in the analyzed matrices. The occurrence of MPs in the biota was high (83.4% and 86.3% in anchovies and spiny oysters, respectively). These results highlighted the high MPs pollution found in the Levantine Basin in comparison to other Western Mediterranean regions. In addition, the obtained results indicate the potential contribution of coastal landfills to this pollution. Most often microplastics studies involve collection of organisms’ samples from natural populations. In this thesis, we tested the feasibility of using transplanted organisms (caging) for monitoring microplastics’ pollution in the marine coastal environment. We developed caging experiments with juvenile European Flounder, Platichthys flesus, in estuarine nursery grounds and blue mussels, Mytilus edulis, in coastal marine environment. For each species, the abundance and characteristics (shape, size, color and type of polymers) of MPs ingested by caged individuals are compared with those ingested by wild individuals collected at the same site and with those found in their surrounding environment (surface water and sediments). Our results suggest that transplanted organisms (caging) may be a promising tool for MPs biomonitoring making monitoring more reliable with an accurate assessment of the biological effects of MPs over a predetermined exposure period

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Germanov, Elitza. "From megafauna to microplastics: Understanding habit use reveals potential threats to Indonesia's manta rays". Thesis, Germanov, Elitza (2020) From megafauna to microplastics: Understanding habit use reveals potential threats to Indonesia's manta rays. PhD thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/56426/.

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Manta rays Mobula alfredi are large, charismatic, filter-feeding elasmobranchs that are threatened with extinction. Limited information on populations within Indonesia exists, despite the growing popularity of manta ray tourism. As a wide ranging, coastal dwelling species, the main threats to manta rays come from fisheries. Within Indonesia, directed fisheries are now prohibited, but incidental capture still occurs and indirect threats from entanglement with fishing gear persist. While the impacts are more cryptic, if unregulated, tourism can also pose threats to manta rays through boat strikes and excessive SCUBA diving/snorkeling disrupting natural behaviors and impacting on important habitats. As filter-feeders, manta rays are susceptible to plastic ingestion in areas heavily contaminated by plastic pollution, like Indonesia. The potential threats posed by microplastics to filter-feeding megafauna are reviewed in Chapter 2. In this thesis, I have investigated the habitat use, demographics and movement patterns of the manta ray inhabiting the Nusa Penida Marine Protected Area (MPA) (Chapter 3) and the Komodo National Park (NP) (Chapter 4), Indonesia. Maximum likelihood techniques and a Markov movement analysis were used to analyze data logged online (www.mantamatcher.org) by researchers and citizen scientists. A larger number of manta rays were recorded within Komodo NP than in the Nusa Penida MPA (~1,100 vs. ~ 600). Within the Nusa Penida MPA, manta rays displayed diverse use of habitats with sites being identified as social areas, foraging grounds and potential nurseries. Sex-based differences in site affinity were also identified with females and immature males having higher site affinity than mature males. Within the Komodo NP there was less differentiation in habitat use between the sexes and between juvenile and older individuals, apart from one site, which had high re-sightings of immature individuals. Tourism, measured by the number of boats present at dive sites, increased by 60% in the Nusa Penida MPA (from 2012 to 2017) and by 34% in the Komodo NP (from 2014 to 2017). Further, persistent threats from artisanal fisheries remain, with 14% of manta rays in the Nusa Penida MPA and 5% of those in the Komodo NP observed with line entanglements or permanent injuries from fishing gear. To assess the abundance of plastic marine debris, including small sized plastics – microplastics, I completed a series of quantitative visual and trawl surveys (n ≥ 6 per season) of feeding grounds for manta rays (Nusa Penida MPA and Komodo NP) and for whale sharks Rhincodon typus (Pantai Bentar, East Java) (Chapter 5). Manta ray feeding grounds were assessed during the two prevailing seasons, the north-west (wet) and south-east (dry) monsoons from 2016 – 2018. Manta ray egested material was collected opportunistically within the Nusa Penida MPA. Floating plastic marine debris was counted visually in transects, while a plankton net trawled for near surface plastics. Plastics were identified, measured and categorized visually from trawl and egested material samples. Linear models found significant seasonal and location differences in plastic abundance with the highest estimates being for the Nusa Penida MPA and coinciding with the wet season. I provided the first theoretical plastic ingestion estimates for both manta rays (up to ~ 63 pieces h-1) and whale sharks (~ 137 pieces h-1) within the Coral Triangle region and confirmed that manta rays both ingest and egest plastic. The results of the population studies (Chapters 3 and 4) were considered when making management recommendations for manta ray conservation in the region, including mandatory codes of conduct for dive operators, carrying capacity restrictions and management zoning. Knowledge gaps were identified and the value and shortcomings of citizen science data collection were outlined. Further, the plastic marine debris studies (Chapter 5) highlighted the potential threat to manta ray and whale shark populations and identified key times for prioritizing plastic marine debris prevention actions. I underline the need for further investigation into the health impacts of plastic ingestion and exposure to plastic associated pollutants, and provide future research directions for establishing the population level effects to these threatened species (Chapters 2, 5, 6 and Appendix I). Focusing research on these umbrella and flagship species could serve to increase public engagement, awareness and foster greater stewardship for overarching marine conservation issues.

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DeAngelo, Cameron. "Investigating the Abundance of Microplastics and Potential Plastic-Degrading Bacteria in Local Freshwater Wetlands". Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:108831.

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Thesis advisor: Heather C. Olins
This study creates a protocol to investigate microplastics in local freshwater wetlands surrounding Boston College. This study also investigated potential plastic-degrading bacteria in the sediment of local freshwater wetlands. A list of potential plastic-degrading bacterial species and genera were compiled from the literature. Using these compiled lists, we searched for these potential plastic-degrading organisms in our metagenomics and 16S datasets. Looking for potential correlations between abiotic factors and the abundance of potential plastic-degrading bacteria, for both data sets, it was found that sandy sediment had a higher abundance of potential plastic-degrading bacteria than non-sandy sediment. Finally, our list of plastic-degrading bacterial species was cross-referenced with a previously compiled list of potential pathogens. Of the 26 taxa in our sites that were identified as potential plastic-degrading bacteria, 57.69% of those taxa are also potentially pathogenic to humans
Thesis (BS) — Boston College, 2020
Submitted to: Boston College. College of Arts and Sciences
Discipline: Departmental Honors
Discipline: Earth and Environmental Sciences

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Puranen, Vasilakis Mikaela. "A comparison between the effects of polylactic acid and polystyrene microplastics on Daphnia magna". Thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-145370.

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The effects of microplastics on zooplankton are an increasing environmental concern. Both primary microplastics that are produced as constituents of cosmetic products, as well as secondary microplastics that are formed by degradation of larger plastic debris, are ubiquitous in aquatic environments. Today, primary microplastics are being phased out and replaced by plant-derived bioplastics. Whether these new materials have similar effects as oil-based microplastics on animals is currently unknown. Here, we compare the effects of secondary microplastic exposure to Daphnia magna, using polylactic acid (PLA) as a representative for bioplastics and polystyrene (PS) for oil-based plastics. To increase the ecological relevance of our tests, we also provided treatments where the particles were coated with bovine serum albumin (BSA) as a means to simulate the coating of biofilms which readily form on particles under natural conditions. Furthermore, to be able to differentiate the effects of general particles from those specific to microplastics, kaolin clay was used as a control treatments, as well as one treatment containing only algae. The objectives were to test the influence of particles on feeding rates, reproduction and growth. PS caused a higher mortality, decreased feeding rate and reproductive output, while PLA and kaolin did not produce any negative effects. BSA did not have a significant effect on reproduction or growth. However, a decrease in reproduction was observed in the plastic treatments. Degradation of PS into styrene monomers is suggested as a possible explanation for the observed toxicity and effects on life history parameters.

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Spinello, Silvia <1996&gt. "Small microplastics (< 100µm), additivi e plastificanti in matrici ambientali: metodi quantitativi e qualitativi". Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/21404.

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Il primo obiettivo di questa tesi è l’identificazione di microplastiche in matrici ambientali utilizzando due tecniche analitiche differenti, la spettroscopia infrarosso con trasformata di Fourier tramite Micro-FTIR e la pirolisi accoppiata alla gas cromatografia-spettrometria di massa (Pyr-GC/MS). Nello specifico, gli stessi campioni analizzati via Micro-FTIR saranno poi analizzati tramite Pyr-GC/MS, per confermare l’identificazione delle microplastiche e per valutare le stesse metodologie preparative con entrambe le tecniche. Il secondo obiettivo è la messa a punto e l’ottimizzazione di metodologie preparative per la quantificazione e la caratterizzazione chimica di small microplastics (< 100 µm), additivi, plastificanti e altre componenti del microlitter in diverse matrici ambientali tramite Micro-FTIR. Le matrici ambientali studiate sono le acque marine del Mar Tirreno, l’aerosol urbano di Venezia, i sedimenti della Laguna di Venezia ed esemplari di Procambarus clarkii, gambero rosso della Louisiana, specie aliena diffusa in tutta Italia. Per le acque marine del Mar Tirreno e per l’aerosol urbano di Venezia è stata messa a punto un’analisi preparativa, che prevede l’elutriazione dal filtro, l’estrazione delle particelle in esame, la successiva purificazione e filtrazione. Per i sedimenti della Laguna di Venezia e per gli esemplari di gambero rosso della Louisiana sono state ottimizzate metodologie preparative precedentemente messe a punto. Poiché per l’analisi quantitativa e qualitativa delle microplastiche e del microlitter è necessario minimizzare la contaminazione, la messa a punto delle metodologie preparative è stata eseguita in una Clean Room ISO 7, priva di materiali plastici.

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Svedin, Jonathan. "Photodegradation of macroplastics to microplastics : A laboratory study on common litter found in urban areas". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80599.

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During the last 60 years the plastic production has increased more than 190 times and plasticpollution both at sea and land is a growing issue. Every year millions of tons of plastic waste fromland reaches the oceans, but the land-based sources are diffuse. One possible source of plasticwaste and microplastics are from plastic litter in urban areas which is common all over the world.The aim with this laboratory study was to study the photodegradation patterns of macroplasticsthat is usually found as litter in urban areas to contribute with knowledge and to theunderstanding of how macroplastics degrade to microplastics. The laboratory study wasstructured around the use of ultraviolet light exposure from UVA 340 nm lamps to acceleratephotodegradations of plastics in air. The test was divided into four different time intervals: stage7 days, stage 14 days, stage 28 days, and stage 56 days to study the evolution of plasticfragmentation over time. Effect of the UV radiation and test duration were combined to derivethe equivalent real time duration. Using Luleå as a benchmark the computed equivalence were0.27 years for every seven days of UV exposure. For stage 7d, a test with different mediums(water and air) were performed to compare the degradation processes between differentenvironments. However, for the longer time intervals air was the only tested environment. Newplastic products were bought which were among the most produced types of plastic or mostcommon plastic litter. The plastics were the following: polystyrene (PS) as plastic coffee cup lid,polypropylene (PP) as chocolate wrapping, polyethylene terephthalate (PET) as plastic bottle,low- density polyethylene (PE-LD) as plastic grocery bag and cellulose acetate (CA) as cigarettefilter or butts. The analytical techniques used were a particle size and number counter, with theselected particle size interval between 4-120 μm, and a camera mounted microscope to studyshapes of microplastic particles. Before photographing the particles, the samples were filtered ona 10 μm aluminium filter. The results showed that photodegradation with UV light did in factaccelerate the degradation process even for short time intervals. Potential for fragmentation ofparticles in air was larger, due to air being a more oxidizing environment and weakening theplastics. The results implied that the degradation processes for PS is slower in water compared tothe other plastics in the same environment. In PS there was a larger amount of particles for theUV- exposed samples compared to the other plastics. This is interpreted as it has a slowerdegradation processes due to the fact when looking on the other plastics in stage w.7 (in water),the control samples have a higher particle count than for the UV exposed samples. It can beinterpreted as PS does not become as effected by the UV light while in water compared to theother plastics. Therefore, the conclusion is that the particles degraded and became smaller thanthe analysed size range (4 μm) and were therefore not detected, consequently, showing a lowerparticle count. After 56 days of UV radiation the largest amount of detected particle mass wasproduced by PP (chocolate wrapping) with 0.0143 mg/cm2 material and the least amount ofdetected particle mass in stage 56d was of PE-LD (plastic bag) with 0.00042 mg/cm2 material.Based on the comparison of the water stage and air stages together with conclusions from earlierstudies, the potential for a substantial destructive breaking of large particle are considered higherin air than in water, because the oxidation weakens the material making it less resilient tomechanical stress.

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Coppola, Giorgio. "Pre-treatment of sewage sludge with Fenton’s peroxidation for the analysis of microplastics by analytical pyrolysis". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24923/.

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Microplastic contamination has emerged as a major global environmental issue. Since this is a global problem of which there is still no accurate quantitative and qualitative knowledge, it is necessary to develop tools for sampling, analysis and modelling of the distribution of these micropollutants. Small plastic particles are now pervasive across marine and freshwater systems. Recently, attention is beginning to focus on the occurrence of microplastics within other environmental compartments such as sewage sludge because have been shown to have a high trapping efficiency for microplastics. However, methods for extracting plastic particles have not yet been systemically tested or standardized. This study investigated a protocol for the removal of organic material during analysis of microplastics from sewage sludge: Fenton’s peroxidation. Attention was paid on the detection and quantification of some of the commercial polymers such as PE, PP, PET, PA6, PC, PS and PVC by Py-GC-MS. The thermoanalytical Py- GC/MS technique can provide qualitative and quantitative information about the microplastics more accurate than already applied optical techniques. In this work, an identification of a methodological approach for the optimization of the Fenton reaction supported by a Design of Experiment was performed, to best interpret the effect of numerous variables of this reaction. The reduction of organic matter was evaluated through the determination of the total organic carbon (TOC) analysis.

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Gomez, Victoria. "Characterization and abundance of macroplastics and microplastics in biotic and abiotic matrices in Concepción Bay, Chile". Doctoral thesis, Università di Siena, 2021. http://hdl.handle.net/11365/1122747.

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In the last decade, increasing concern has been raised to protect the marine environment from plastic pollution. Plastic has the potential to break down into microscope and nanoscope particles (secondary microplastics). Among them, microplastics (MPs) (also known as emergent pollutants=EC) are fragments of grain size lower than 5 mm. The characteristics of plastics such as colour, heat resistance, etc., change thanks to the adhesion of chemical substances, called additives. In some cases, the additive ingredients constitute up to 50% of the proportion of the plastic product. Phthalate esters, bisphenol A (BPA), brominated flame retardants (BFRs) are among many other plastic additives known as toxic compounds to organisms when released to the environment. Also, because of their properties, plastics sorbed a complex mixture of chemical contaminants present in the surrounding environment. It is estimated that of the total annual plastic consumption in Chile, only 8.5% is recycled. However, this includes both post-industrial waste and household solid waste. If only the recycling of household plastic waste is measured, the recycling percentage is only 1.4% of the total plastic consumed each year in Chile. This study evaluated the state of contamination by plastics (micro and macroplastics) on the coasts of the province of Concepción, Chile, specifically in Coliumo Bay, Concepción Bay and on the adjacent beach at the mouth of the Biobío River. The main results of this study were to conduct the first information of POPs sorbed in macroplastics collected on beaches of coastal areas in Chile and characterization and abundance of microplastics collected in the sand and fish. Identification/characterization of polymer types in plastics was done using Fourier-transform infrared (FT-IR) spectroscopy and an optical microscope with an integrated camera. This is essential because it allows an assumption on the source of the plastic pollutants and governs its origin from the break down of macro, larger or extra-large plastic components or nearby recreational and industrial activities. In the coast of central Chile, fragment and fibres account for 100% of the collected MP particles, indicating the presence of secondary MPs in Concepcion Bay and the most frequent plastics identified were polystyrene foam beads (46% in sand) and Polyethylene (PE) (75% in fish). Black fragments were the most abundant microplastics both in the biotic and abiotic samples of Concepción Bay. The abundance of microplastics in the sand was 0.035 ± 0.04 items/g and 1 item/individual in fish (Trachurus murphyi (Chilean jack mackerel) and Merluccius gayi (Hake)). Regarding macroplastics, the average abundance was 2 items/m2 less than in other studies. The highest abundance of macroplastic types were the fragments and the most frequent plastics identified were polypropylene (PP) (38%), mostly white. Also, to determine the chemical load, such as persistent organic pollutants (POPs) found in plastic waste, they were analysed using ultrasonic extraction and gas chromatography–mass spectrometry (GC-MS) for POPs determination. Screened compounds were PBDEs (n = 10), PCBs (n = 7), and OCPs (n = 13). High concentrations of PBDEs were found ranging from 2.1 to 1300 ng/g in the spring of 2017 and 392 to 3177 ng/g in the summer of 2018. Σ7PCBs ranged from 0.9 to 93 ng/g during the spring of 2017 and 0.3 to 4.5 ng/g for the summer of 2018. The concentrations of OCPs (DDX and HCHs) were low and were only detected in the summer of 2018. The plastics found in this study are commonly used in commercial, fishing, and household activities. These findings reinforce the need to improve effective sustainable management actions of solid waste treatment and disposal in the Coastal cities of Chile, also taking into account the chemical burden associated with plastic waste.

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Katzenberger, Tim Dominik. "Assessing the biological effects of exposure to microplastics in the three-spined stickleback (Gasterosteus aculeatus) (Linnaeus 1758)". Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/12579/.

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The global pollution of aquatic environments with microplastics and their interaction with wildlife is of concern. Ingestion of plastic has been reported for a wide range of species but little is known about the potential effects of such ingestion. The aim of this thesis was to assess the biological effects that are induced by the ingestion of microplastic in the three-spined stickleback (Gasterosteus aculeatus). Novel data for the ingestion, retention, egestion and induced effects of microplastic in multiple ontogenetic life stages are presented. Microplastics of different types and sizes were found to be ingested from the water and diet. Additionally, trophic transfer of microplastic was found as a further route for ingestion. Whereas ingestion of relatively small plastic was not found to induce blockages or obstructions of the gastrointestinal tract, ingestion of relatively large plastic had the potential to result in prolonging effects on food digestion. However, all used microplastics were found to be egested successfully. Effects on length, weight and condition index K were found but varied between exposure types and data suggests that observed short term effects were induced by plastic associated chemicals. Whereas molecular analysis of cytochrome P450 1A confirmed exposure to xenobiotics, relative expression of vitellogenin indicated no exposure to oestrogenic, plastic derived chemicals. Degraded polymer structures showed to have a higher biological activity due to enhanced leaching of endocrine disrupting, plastic derived chemicals and showed a potential to disturb energy metabolism. In addition, plastic was found to act as vectors for absorbed bisphenol A from the water column via trophic transfer to stickleback larvae where desorption of accumulated chemicals had the potential to induce toxic effects. The data presented in this thesis indicate that microplastics can be ingested and can induce negative effects in multiple ontogenetic life stages of sticklebacks.

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Ziajahromi, Shima. "Identification and quantification of microplastics in wastewater treatment plant effluent: Investigation of the fate and biological effects". Thesis, Griffith University, 2018. http://hdl.handle.net/10072/378550.

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Microplastics (i.e., plastics particles < 5mm) are widespread emerging contaminants that have been detected in various aquatic environments worldwide including freshwater and marine ecosystems. Contamination of the environment with microplastics has become an environmental issue due to the potential of plastics to remain for thousands of years and to accumulate in the aquatic environment. The abundance of microplastics in the aquatic environment is assumed to increase due to continuous fragmentation of macro and microplastic debris, which can lead to a decrease in the average size ranges of microplastics over time (Cole et al., 2011). Moreover, concerns have been raised regarding the potential of microplastics to physically (e.g., blockage of digestive tract) and chemically (e.g., leaching of sorbed chemicals and toxic additives) harm aquatic organisms. Microplastics can enter the aquatic environment from both aquatic-based and landbased sources. Recently, wastewater treatment plants (WWTP) have been identified as one of the important land-based sources of microplastics. While microplastics have been reported in WWTP effluent in Asia, Europe, USA and Russia, little is known about the presence of microplastics in Australian WWTP effluent. More importantly, the lack of standardized techniques to sample and characterize microplastics in environmental samples, especially in complex samples such as wastewater, has led to inaccurate estimations of microplastic concentrations. In response to the current knowledge gaps, a novel validated high-volume sampling device was developed for in situ fractionation of microplastics from wastewater effluent as part of this project. The developed method was applied to three Australian WWTPs utilizing primary, secondary and tertiary treatments to provide a snapshot of the fate and removal of microplastics during various wastewater treatment processes. To achieve an accurate estimation of microplastics, the sampling technique was combined with an efficient sample processing method. Microplastic polymer type, shape and potential origin were further determined using microscopy analysis and Fourier Transform Infrared (FTIR) spectroscopy. The efficiency of the sampling device was found to be between 92 to 99% for 500 and 25 μm mesh screens. The results showed that the concentrations of microplastics were 1.5, 0.6 and 0.2 microplastics per liter of effluent in primary, secondary and tertiary effluent, respectively. It was also found that the majority of detected microplastics in the studied WWTPs were polyethylene terephthalate (PET) fibers, which is assumed to originate from synthetic clothing. Polyethylene (PE) beads and fragments, which may be associated with cosmetic products, were the second most frequently detected type of microplastic. Despite a thorough sample processing method, FTIR spectroscopy revealed that between 22 to 90% of the suspected microplastic particles were in fact non-plastic particles. This study suggests that WWTPs can act as a significant source of microplastics to the aquatic environment given the large volume of wastewater discharged to the aquatic environment. To date, the effects of microplastics on aquatic organisms have mostly been examined using high and often unrealistic concentrations of microplastics (e.g., milligram per liter range). Moreover, while the presence of different types of microplastics together in aquatic ecosystems has been widely reported, the potential effects of microplastics when they occur as mixtures are largely unknown. To cover these knowledge gaps, the potential adverse effects of wastewater-based microplastics (such as fibers and beads) at lower concentrations on the freshwater organism Ceriodaphnia dubia were evaluated. The acute (48 h) and chronic (192 h) effects of PET fibers and PE bead microplastics on C. dubia were assessed alone and as a binary mixture. The results showed a dose-dependent trend on survival, with C. dubia more sensitive to PET fibers than PE microplastics. The 48 h EC50 value of fibers was 1.5 mg/L compared to 2.2 mg/L for PE beads. The binary mixture of microplastic beads and fibers demonstrated less than additive effects. EC50 values for the chronic bioassay were 429 μg/L for fibers and 958 μg/L for PE microplastics. A positive trend of decreasing growth (body size of adults) and reproduction rate (number of neonates) with increasing microplastic concentration was observed for both PE and fiber microplastics during the chronic bioassays. Using scanning electron microscopy (SEM) we observed deformities, such as carapace and antenna deformation, in C. dubia exposed to fibers at a high concentration, but not at the lower (environmentally relevant) concentrations. Given the likelihood that microplastics will eventually sink to the bottom sediment in the aquatic ecosystem the effects of microplastics were investigated on a freshwater sediment-dwelling organism (Chironomus tepperi) at environmentally relevant concentrations of PE microplastics (500 particles/kgsediment). Possible size-dependent effects of microplastics were also examined using four different size ranges of PE beads including 1-4, 10-27, 43-54 and 100-126 μm. The results revealed that exposure to an environmentally relevant concentration of microplastics had a detrimental impact on the survival, growth (i.e., body length and head capsule) and emergence of C. tepperi. The observed effects were strongly dependent on microplastic size with C. tepperi more sensitive to microplastics in the size range of 10-27 μm. No negative effects were observed on growth and survival of C. tepperi exposed to the larger microplastics (100-126 μm), though a significant decrease in the number of emerging adults was observed in the organisms exposed to the same size range of microplastics. Further, SEM showed a significant reduction in the size of the head capsule and antenna in C. tepperi exposed to microplastics in the size range of 10-27 μm. These results showed that environmentally relevant concentrations of microplastics in sediment can result in adverse effects on the development and emergence of C. tepperi, with effects strongly dependent on particle size. Finally, we evaluated the effects of PE microplastics on the acute toxicity of a pyrethroid insecticide (bifenthrin) to midge larvae (C. tepperi) in water. To test the single and combined effects of bifenthrin and PE microplastics, C. tepperi larvae were exposed to six concentrations of bifenthrin ranging from 0.1 to 3.2 μg/L in the presence and absence of microplastics. To examine the possible effects of bifenthrin and microplastics in synthetic and real water, the bioassays were performed in both moderately hard water (MHW) and river water. We performed an uptake study using three different size ranges of microplastics (10-27, 43-54, 100-126 μm) during 8-day microplastics-spiked water exposure. The results showed that microplastics in the size range of 10-27 μm were mostly ingested by C. tepperi larvae. Using this finding, 10-27 μm microplastics were selected for the bioassays. The results of the bioassays using MHW demonstrated a significant decrease in the toxicity of bifenthrin in the presence of microplastics. This is likely attributable to the tendency of bifenthrin to bind to the microplastics, which reduces the bioavailability of bifenthrin to midge larvae. However, in the bioassays conducted in river water with a total organic carbon (TOC) concentration of 9.6 mg/L, no significant difference was observed between the toxicity of bifenthrin to C. tepperi in the presence and absence of microplastics. This is likely due to the interaction between organic carbon and bifenthrin, which reduces the bioavailability of bifenthrin to C. tepperi larvae. This thesis highlights that microplastic fibers and beads are released to the aquatic environment from WWTPs, and that this can negatively affect survival, reproduction and the life cycle of aquatic organisms (both pelagic and benthic) through entanglement (fibers) and ingestion (beads). The effect of microplastics on chemical contaminants is complex, and microplastics may act both as carriers but also as “chelators” of chemicals in the water, thereby reducing their bioavailability.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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PITTURA, LUCIA. "Ecotoxicological Approach as a Tool to Suggest Strategies for Risk Management of Microplastics in the Marine Environment". Doctoral thesis, Università Politecnica delle Marche, 2019. http://hdl.handle.net/11566/263259.

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In questa tesi, la distribuzione delle microplastiche (MP) lungo una tipica rete alimentare marina è stata valutata in specie rappresentative dal Mare Adriatico settentrionale, centrale e meridionale. I risultati hanno mostrato che l’ingestione di MP è diffusa, con la presenza di almeno una particella in circa il 26% dei 475 campioni analizzati. Frequenze più alte sono state riscontrate negli organismi del Centro e del Sud rispetto al Nord, suggerendo l’influenza delle diverse caratteristiche idrografiche. Invece, non è stato possibile definire una chiara relazione tra abbondanza di MP ingerite e posizione trofica, modalità di alimentazione o habitat delle specie. La caratterizzazione delle MP estratte, mediante microscopia e tecnologia μFTIR, ha evidenziato differenze geografiche anche in termini di dimensioni, forma e tipologia dei polimeri. Gli effetti ecotossicologici delle MP e il loro ruolo nel veicolare IPA sono stati studiati nei mitili mediterranei esposti a MP di polietilene, vergini e pre-contaminate con benzo(a)pirene. Dopo l’ingestione, le MP sono state riscontrate in diversi tessuti causando un significativo bioaccumulo di B(a)P. Le analisi dei biomarkers molecolari e cellulari hanno evidenziato l’elevata suscettibilità del sistema immunitario, mentre effetti minori sono stati misurati per il sistema antiossidante, la perossidazione lipidica, le risposte neurotossiche e genotossiche. La minaccia delle MP per gli ecosistemi acquatici sta ponendo nuove sfide anche nella gestione degli impianti di trattamento delle acque reflue, che sono una via di rilascio di MP in ambiente. L’efficienza dei diversi processi di trattamento nella rimozione delle MP da l’influente è stata valutata in un impianto italiano. È stata rilevata una riduzione step by step delle MP e un’efficienza di ritenzione totale dell’ 84%. Tuttavia, è stato stimato un rilascio di ancora 160000000 MP/giorno attraverso l’effluente e una grande quantità di particelle viene depositata nei fanghi, riutilizzati in agricoltura. Lo studio ha fornito nuove informazioni sulla distribuzione delle MP negli organismi adriatici, sulla loro potenziale tossicità e sulla necessità di migliorare le tecnologie negli impianti di trattamento delle acque reflue per limitare gli input di MP in ambiente.
Microplastics (MPs) are ingested by marine organisms at all trophic levels with the potential to induce adverse biological effects. In this thesis, the distribution of MPs along a typical marine food web was assessed in representative species from the Northern, Central and Southern Adriatic Sea. Results revealed that MPs ingestion is widespread, with the occurrence of at least one item in approximately 26% of the 475 analyzed specimens. Higher frequencies were observed in organisms of Central and Southern areas than of the Northern, suggesting the influence of the different hydrographic characteristics. Instead, no clear relationship could be define between abundance of ingested MPs and trophic position, feeding mode or habitat of species. Characterization of extracted MPs by microscopy and µFTIR technology highlighted geographical differences also in terms of size, shape and polymer typology. The ecotoxicological effects of MPs and their role as vehicles of PAHs were investigated in the Mediterranean mussels exposed to polyethylene microparticles, both virgin and pre-contaminated with benzo(a)pyrene. After ingestion, MPs were observed in different tissues causing a significant bioaccumulation of B(a)P. Analyses of molecular and cellular biomarkers highlighted the high susceptibility of the immunological parameters, while minor effects were measured for antioxidant system, lipid peroxidation, neurotoxic and genotoxic responses. The threat of MPs in aquatic ecosystems is posing new challenges also in managment of Wastewater Treatment Plants, which represent one route for MPs to enter the environment. An Italian facility was selected to assess the effeciency of different wastewater treatment processes in removing MPs from the influent. A step by step reduction of MPs was detected, with a total removal efficiency of 84%. However, 160,000,000 MPs/day are still released by the plant, mainly of polyester and polyamide and a great amount of MPs is deposited in the sludges, that are re-used in agriculture. This study provided new insights on distribution of MPs in Adriatic organisms, their potential toxicity and the need to improve technologies in WWTPs to limit MPs input in the environment.

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Piarulli, Stefania <1991&gt. "The role of biological processes in affecting the dynamics and fate of microplastics in coastal marine systems". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9440/1/Stefania%20Piarulli_PhD%20thesis.pdf.

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Microplastics (MP) are omnipresent contaminants in the marine environment. Ingestion of MP has been reported for a wide range of marine biota, but to what extent the uptake by organisms affects the dynamics and fate of MP in the marine system has received little attention. My thesis explored this topic by integrating laboratory tests and experiments, field quantitative surveys of MP distribution and dynamics, and the use of specialised analytical techniques such as Attenuated-Total-Reflectance- (ATR) and imaging- Fourier Transformed Infrared Spectroscopy (FTIR). I compared different methodologies to extract MP from wild invertebrate specimens, and selected the use of potassium hydroxide (KOH) as the most cost-effective approach. I used this approach to analyse the MP contamination in various invertebrate species with different ecological traits from European salt marshes. I found that 96% of the analysed specimens (330) did not contain any MP. As preliminary environmental analyses showed high levels of environmental MP contamination, I hypothesised that most MP do not accumulate into organisms but are rather fast egested. I subsequently used laboratory multi-trophic experiments and a long-term field experiment using the filter-feeding mussel Mytilus galloprovincialis and the detritus feeding polychaete Hediste diversicolor to test the aforementioned hypothesis. Overall, results showed that MP are ingested but rapidly egested by marine invertebrates, which may limit MP transfer via predator-prey interactions but at the same time enhance their transfer via detrital pathways in the sediments. These processes seem to be extremely variable over time, with potential unexplored environmental consequences. This rapid dynamics also limits the conclusions that can be derived from static observations of MP contents in marine organisms, not fully capturing the real levels of potential contaminations by marine species. This emphasises the need to consider such dynamics in future work to measure the uptake rates by organisms in natural systems.

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Reis, Patrícia Isabel Nunes. "Microplastic contamination in Argentina: insights about a source (wastewater treatment plant) and a sink (beach): 2 case studies". Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19528.

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Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia
Microplastics (MPs) are a contaminant which due to its ubiquitous nature is spread all over the world, reaching all the ecosystems and remote places. Since it’s a recent topic in the scientific community and its elimination is still a challenge, it’s important to access its concentration worldwide and monitoring. Some countries don’t have or have scarce data about it. Argentina, which comprises a long Atlantic coast and manages one of the major estuaries of South America is highly susceptible to release and transport MPs, but its concentration hasn’t been broadly studied yet. This thesis aims to contribute to filling the existent knowledge gap by presenting two case studies: one representing a sink for Potential Microplastics (PMPs), three beaches from Villa Gesell (Great Buenos Aires); and a source, a communitarian Wastewater Treatment Plant (WWTP) in the Great Buenos Aires area, to understand the transport of PMPs to the environment. PMPs were quantified and classified optically by its shape and colour. In Villa Gesell, PMPs were investigated in three different beaches with different anthropogenic loads, ranging from 46.0±34.8 (SD) to 86.2±66.1 PMPs.Kg-1 dry sand. No relation was observed between the amount of PMPs with anthropogenic load, wracklines, sand-size grain, and organic content. In WWTP, the concentration of PMPs in the influent was 12587±3073 PMPs.L-1 and it’s suggested that lagoon system and secondary settler could remove PMPs. However, still releases to the aquatic ecosystem an amount of 9.1x109 PMPs.day-1. Since the PMPs were not eliminated, they remained in the sludge, reaching an amount of 2.7x105±2.9x105 PMPs.kg-1 of dry sludge. The results from this thesis show the importance of assessing PMPs to understand the dimension of the contamination, bring awareness on this problem that can have serious consequences to the biota, and motivate the development of strategies to eliminate this contaminant
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Björk, My y Linn Månsson. "Mikroplasters spridning längs den svenska västkusten - En studie om koncentration och distribution av mikroplaster i marina sediment". Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22550.

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På senare år har ett nytt forskningsområde kring mikroskopiska plastfragment i marin miljö,kallat mikroplaster, vuxit fram. Mikroplaster härstammar från antropogena källor somavloppsreningsverk och vid fragmentering av makroplast. Det finns ett begränsat antal studierinom området, särskilt vad gäller svenska vatten, vilket innebär att det finns utrymme för merforskning. För att bidra till forskningen har föreliggande studie undersökt sedimentprover frånlitoralen vid sju olika platser längs svenska västkusten samt ett sedimentprov från djupt vattenvid en av platserna. För att undersöka koncentration och distribution av mikroplaster utfördeskorrelationsanalys längs den svenska västkusten mellan mikroplaster och två variabler;kornstorlek och salinitet. Resultatet visade att högst koncentration av mikroplaster återfannsvid Sveriges västkust norra delar och minskade ju längre söderut proverna togs.Förklaringsgraden R2 = 0, 61 visade stark korrelation mellan koncentration mikroplaster ochhög salinitet, samt fanns en korrelation mellan mikroplaster och grov sand medförklaringsgraden R2 = 0,38. Resultaten bidrar till ökad förståelse för hur mikroplasterdistribueras i marin miljö vid den svenska västkusten. Forskarna uppmanar till flerprovtagningar i havets alla zoner för att bättre förstå hur mikroplaster koncentreras ochdistribueras i marin miljö.
In recent years, a new research field regarding microscopic plastic fragments in the marineenvironment, called microplastics, have emerged. Microplastics derives from anthropogenicsources such as sewage treatment plants and the fragmentation of macro plastic. There are alimited number of studies regarding micro plastics, especially concerning Swedish waters,indicating the need for more research. In this study sediment samples were collected from thelittoral area at seven different locations as well as one sediment sample from a deep sea at oneof the sites. The aim is to investigate the concentration and distribution of microplastics alongthe Swedish west coast. A correlation analysis was performed between microplastics and twovariables; grain size and salinity. The results showed that the highest concentration of microplastics were found at the north part of the Swedish west coast and decreased the farther souththe samples were taken. The results showed a strong correlation between microplastics andhigh salinity R2 = 0, 61, and a correlation was seen between micro plastics and coarse sandwith a R2 = 0.38. The results contribute to the understanding of how micro plastics aredistributed in marine environment along the Swedish west coast. The researchers behind thisstudy calls for sampling of all marine zones to further understand how microplastics areconcentrated and distributed in the marine environment

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48

Nguyen, Thu Ha. "Flocculation dynamics of cell-associated suspended particulate matter". Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23148.

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Transport of suspended particulate matter (SPM) plays a vital role in controlling large-scale processes related to geophysical flows such as dispersal and sinking of organic matter and contaminants to offshore and deep waters, nutrient cycles, food web stability, morphodynamics and sedimentation in both limnetic and pelagic ecosystems. Although it has been recognized that small-scale microbial processes can introduce substantial differences to the way in which SPM moves in natural waters, the extent to which the attached biological matter affects SPM dynamics is still not well characterized. This thesis focuses on quantifying the attached biomass fraction on SPM aggregates and investigating its contribution to SPM flocculation dynamics, which consequently control SPM aggregate geometrical properties and transport. A novel laboratory-based Optical Measurement of Cell Colonization (OMCEC) system and a microbiological-physical model (BFLOC2) are the main achievements of this thesis that allow the analyses of the correlations between environmental conditions, aggregate-attached biomass fraction, cell colonization patterns, aggregate size, fractal dimension and settling velocity. OMCEC is an experimental system that can simultaneously measure the material composition, geometric properties, and motion of individual suspended aggregates in a non-invasive and non-destructive way. OMCEC consists of a full-color high-resolution optical system and real-time algorithms for (i) material segmentation based on light spectra emission analysis, (ii) quantification of various geometrical properties, and (iii) motion detection with micro particle tracking velocimetry (μPTV). OMCEC was applied herein on three types of aggregates: cell-associated minerals, cell-associated microplastics, and three-phase aggregates made of minerals, microplastics, and biological matter. OMCEC application on Saccharomyces cerevisiae-colonized minerals at four sucrose concentrations showed the likelihood of cell colonization to increase with increasing nutrient concentration. The attached biomass fraction was found to increase nonlinearly regarding an increase of aggregate size but almost constant with fractal dimension variation. Cell distribution on mineral surfaces was then analyzed and classified into three colonization patterns: (i) scattered, (ii) well-touched, and (iii) poorly-touched, with the second being predominant. Cell clusters in the well-touched pattern were found to have lower fractal dimension than those in the other patterns. A strong correlation of colonization patterns with aggregate biomass fraction and properties suggests dynamic colonization mechanisms from cell attachment to minerals, to joining of isolated cell clusters, and finally cell growth over the entire aggregate. OMCEC application on microplastics (MPs) being colonized by natural biological matter from Hawkesbury River, NSW, Australia demonstrated that the biomass fraction of MP aggregates has substantial control over their size, shape and, most importantly, their settling velocity. Polyurethane MP aggregates made of 80% biological matter had an average size almost double that of MP aggregates containing 5% biological matter and sank two times slower. Based on our experimental data, we introduce a settling velocity equation that accounts for the shape irregularity and fractal structure of MP aggregates. This equation can capture the settling velocity of both virgin MPs and cell-associated MP aggregates with 7% error and can be applied widely to predict the settling flux of MP aggregates made of different polymers and various types of biological matter. To consider the complex genesis of cell-associated mineral aggregates, the BFLOC2 model was introduced to predict aggregate geometry and settling velocity under simultaneous effects of hydrodynamic and biological processes. While minerals can contribute to aggregate dynamics through collision, aggregation, and breakup, living microorganisms can colonize and establish food web interactions that involve growth and grazing, and modify the aggregate structure. Modeling of cell-associated mineral aggregate dynamics over a wide range of environmental conditions showed that maximum aggregate size, biomass fraction, and settling velocity could occur at different optimal environmental conditions. Unlike mineral aggregates, which have maximum size when shear rates tend to zero, a relative maximum size of cell-associated mineral aggregates can be reached at intermediate shear rates as a result of microbiological processes. The settling velocity was ultimately controlled by aggregate size, fractal dimension, and biomass fraction. The innovative aspect of this thesis is the simultaneous quantification of composition, architecture, and settling velocity of individual aggregates. Therefore, it puts forth the analysis and prediction of cell colonization impacts on dynamics and transport of suspended particulate matter in natural waters. The output of this thesis can be used in natural water monitoring programs to estimate the biological content based on SPM size, capacity dimension, and settling velocity, which can be measured using in-situ methods. Furthermore, the evidence and tools to quantify the sinking and floating of microplastic subjected to bio-fouling can be implemented in microplastics transport models to enable the three-dimension modeling of both low- and high-density microplastics. The BFLOC2 model can be coupled to traditional sediment transport models to better describe the sediment formation dynamics, thus giving a more precise prediction of sedimentation and carbon flux to deep waters and offshore.

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49

DI, NATALE Marilena Vita. "Impacts of weathered microplastics on bioavailability of pollutants in Paracentrotus lividus and Danio rerio: molecular and ecotoxicological approaches". Doctoral thesis, Università degli Studi di Palermo, 2022. https://hdl.handle.net/10447/560342.

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Plastic materials provide countless applications in every sector of human life, from food and health preservation to textiles and electronics industry (Cole et al., 2011;Thompson et al., 2009) which is resulting in huge amount of plastic waste. Recently, it was estimated that plastics account for the 80-90% of the whole marine litter (Derraik, 2002) and over 5 trillion microscopic plastic fragments are floating on the surface of the World Oceans (Eriksen et al., 2014). The predominant form of marine plastic litter is called “Microplastics (MPs)", terminology by Thompson et al. 2004, used to indicate small plastic fragments, fibers and granules of microscopic size (1 μm to 5 mm in diameter). Being small in size, they are likely to be ingested and accumulate by different classes of organisms (Wright et al., 2013), even can be consumed by algae and bacteria (Mattsson et al., 2015; Bouwmeester et al., 2015). Their presence, therefore, can represent a growing threat to ecosystems and to organisms for which it can represent a hazard (Galloway and Lewis, 2016). MPs are known to interact with a variety of chemicals in the environment through many sorption mechanisms (Yu et al., 2019). Owing to their ability to sorb xenobiotic chemicals, MPs are regarded as vectors of hazardous contaminants to aquatic organisms (Torres et al., 2021). The study of the interactions and the sorption mechanisms occurring between the sorbent (microplastic polymer) and sorbate (chemical contaminant) are important to improve our understanding of MP-mediated contaminant transfer as well as the impact of MPs on the marine environment, especially considering MPs from natural environment. MPs in natural environments undergo weathering processes due to physico-chemical interactions with environmental stress, including with biota. Over time, these stressors may lead to a progressive degradation of plastic polymers and affect their sorption capacity as well as their behavior in aquatic environments. In this context, it is key to know the bioavailable fraction able to determine a potential ecotoxicity in organisms, and to investigate the role of MPs in transferring bioavailable hazardous chemicals to aquatic biota. A multidisciplinary approach to evaluate the influence of the different factors altering plastic surface as well as to investigate the interactions behind the complex mixtures between toxicants and MPs should be considered. The aim of this chapter is to review the main MPs properties focusing particular reference on the sorption mechanisms of MPs, the factors that influence those mechanisms, the sorption behavior of a wide range of chemical contaminants and toxicity associated to combined exposures to MPs and pollutants. An overview of studies that allow relating toxicity to the sorption to MPs and help understand its importance for the bioavailability of chemical compounds is included. A pilot study carried out to evaluate the sorption, over time, of different metals and BDE-47 on a pristine model MP is described. Finally, the objectives of this thesis are presented.

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50

Mandekar, Bedraya E. A. "Investigation of the role of microplastics in the transport of potentially toxic element species in the marine environment". Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30288.

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There is growing global concern about the impact of microplastics on the marine environment, with evidence emerging that plastic pellets can be a vector for potentially toxic elements (PTE). In this thesis, PTE content was first investigated in petroleum based (polyethylene, polypropylene and polyethylene terephthalate) and bio-based (poly(hydroxybutyrate-co-hydroxyvalerate)) virgin plastic pellets. Various elements associated with plastics' manufacture were detected. Next, sorption experiments were conducted to assess the capacity of virgin and laboratory-weathered pellets to take up As, Cd, Cr and Pb from controlled media of deionised, fresh and artificial seawater, with analysis by ICP-MS (Agilent 7700x instrument). All types of plastics showed the ability to take up the PTE studied and the total amounts were in the order Pb > As > Cd > Cr when single element solutions were studied and Pb > Cd > Cr > As from a multi-element solution. It was found that weathered pellets took up greater amounts of PTE than virgin ones. The surface of virgin, laboratory-weathered and beached pellets collected from Kuwait and Scotland were then imaged and their chemical composition determined using a scanning electron microscope with energy-dispersive EDS analyser (JEOL JSM-6010LA). Analysis revealed changes in pellet morphology following weathering. Elements detected were associated with aspects of plastic production or taken up from the ambient environment. Beached pellets were identified by ATR-FTIR as predominantly polyethylene and polypropylene. When examples were subjected to sequential cold acid digestion followed by microwave extraction, larger amount of PTE were released by the cold digestion step, indicating the analytes were relatively weakly bound. Samples from Kuwait released higher amounts of PTE than samples from Scotland. In vitro bioaccessibility of PTE to simulated fish stomach was estimated using two methods, a modified SBET and a 0.1 M HCl extraction. Lead was found to be the most bioaccessible of the PTE studied.

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