Microplastics are small piece of plastic debris < 5 mm in diameter, which arise and enter the environment either as a consequence of the direct release of small pieces of plastic debris or as a consequence of the fragmentation of larger items. They are widely distributed in the marine environment, on shorelines, at the sea surface, on the seabed. They are also ingested by a variety of marine organisms, and there is some evidence that this may cause adverse effects. This thesis investigates the potential sources, distribution and fate of this contaminant. Deterioration of plastics in a variety of environments was examined as a potential source of microplastics. Plastics were exposed in light and shade, in air, fresh water and sea water. Their deterioration was monitored over six hundred days. The fastest rate of deterioration, by far, was observed in air, and this was further accelerated by natural sunlight. Degradation in water was much slower and it was therefore concluded that plastic debris only fragments slowly into microplastics while they are in the water, and much faster when they are washed ashore and/or remain exposed to air, for example on a beach. A method to assess the contamination of beaches by microplastics' likely predecessors - small items of plastic debris - was therefore developed. High spatial variability, which can impede comparison between surveys undertaken by random sampling was overcome by assessing deliberately selected debris accumulations. An attempt to utilise citizen science using this rapid survey approach returned too much variability between volunteers to obtain consistent results. Nevertheless, the survey method was successfully used to identify narrow opening towards the sea, small tidal range and several weeks of high on-beach waves as predictors for high contamination. Evidence of harmful effects of microplastics on animals is primarily from laboratory studies and could be substantiated by exposure experiments \emph{in-situ}. Cockles were exposed to fluorescent plastic particles in an intertidal mudflat. After two weeks, particles were still present in the sediment. However, the test material could not be identified in the cockles with enough certainty to validate the method. The thesis concludes that fragmentation of larger items of debris on land is an important potential source of microplastics. Therefore, preventing plastics that are prone to deteriorate from entering the environment is likely the most effective way to prevent the generation of microplastics. Measuring the success of such preventive measures in the field returns highly variable results, as small plastic debris are elusive. Measuring effects in the environment demands large amounts of data, and highly specific methods are required to detect microplastics in animals. The shift of environmental plastic contamination towards small particles demands that plastic debris research adjusts to the elusiveness of these particles. Large volumes of variable data on plastics density and precise biological essays will be required.

‘Microplastics’ are pieces of plastic debris < 5mm in diameter. They are introduced into the marine environment directly for example via release of small pieces of plastics used as abrasives and indirectly through the fragmentation of larger items. The European Marine Strategy Framework Directive 2008/56/EC (MSFD) regards microplastics as an emerging issue of concern and calls for more data on the quantity, distribution and composition of this debris. This thesis examines the amount, composition and distribution of buoyant microplastic debris in marine waters using different sampling devices and methodologies. To investigate the spatial distribution, abundance and composition of microplastic debris between nearshore and offshore marine subsurface waters a subset of samples from the Continuous Plankton Recorder (CPR) survey were examined. Abundance was generally higher in nearshore coastal waters than the offshore oceanic samples, with the highest mean concentrations observed in the UK’s coastal waters of the northeast Atlantic and the southern North Sea. To validate the accuracy of the presence/absence of microplastic debris reported in the Continuous Plankton Recorder (CPR) samples by analysts at the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) a subset of data was formally analysed using Fourier Transform Infrared (FTIR) spectroscopy. This analysis indicated a good level of accuracy (~66%) in the ability of the SAHFOS’ analysts to detect visually microplastic fragments during their normal processing of plankton samples. To compare quantity and composition of buoyant microplastic debris collected by two different approaches (CPR vs. Manta net) samples were collected from a similar body of coastal waters. The results showed significantly higher abundance of microplastic in samples collected by the manta net per unit of distance but no significant difference once the results were standardised per cubic volume of water. To assess the susceptibility of each method to ‘procedural contamination’, repetitive controlled tests were conducted to quantify the amount and composition of contaminants before, during and after the sampling programme. In both methods the highest number of contaminants was found on the net and prior to the deployment to sea. The semi synthetic Rayon fibres were the most abundant type of contaminants in both cases. To compare the abundance and composition of buoyant plastic debris in estuarine waters according to daily and lunar tidal cycles a mensurative experiment was conducted in a macrotidal Estuary. Microplastics comprised 82% of the debris and there was a significant difference in size frequency distribution between the spring and neap tides with more fragments of larger size observed during spring tides. In conclusion, this study shows further evidence of the spatial heterogeneity of microplastic debris distribution in marine waters and therefore also highlights the need for more comparable data from different marine habitats using standardised methodologies.

abstract: The occurrence of micro-and nanoplastic (MNP) debris in the environment is a research area of considerable public health concern. Various combinations of methods for extraction, isolation, and quantification of MNP have been applied but literature studies evaluating the appropriateness and efficacy of these protocols are lacking. A meta-analysis of the literature (n=134; years 2010-2017) was conducted to inventory and assess the appropriateness of methodologies employed. Some 30.6% of studies employed visual identification only, which carried a calculated misidentification error of 25.8-74.2%. An additional 6.7% of studies reported counts for particles smaller than the cutoff value of the selected collection pore size, and 9.7% of studies utilized extraction solution densities which exclude some of the polymers commonly occurring in the environments investigated. A composite value of data vulnerability of 43.3% was determined for the sample, indicating considerable weaknesses in the robustness of information available on MNP occurrence and type. Additionally, the oxidizing solutions documented in the literature frequently were deemed unsuccessful in removing interfering organic matter. Whereas nanoplastics measuring <1 µm in diameter are likely principal drivers of health risk, polymer fragments reported on in the literature are much larger, measuring 10+ µm in diameter due to lack of standardized methods. Thus, current inventories of MNP in the environmental MNP feature data quality concerns that should be addressed moving forward by using more robust and standardized techniques for sampling, processing and polymer identification to improve data quality and avoid the risk of misclassification. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2018

Microplastics (MPs) are small pieces of plastic material including tyre wear particles (TWPs) smaller than 5000 µm. One of the primary pathways through which MPs including TWPs enter aquatic and marine environments is stormwater runoff from urban areas. The aim of this thesis is to advance the knowledge of MPs found in sediments from gully pots and stormwater ponds, as well as increase the understanding of and assess one of the sources of secondary MPs, i.e. UV-degradation of four commonly found plastic litters. To advance the knowledge, an experimental approach was used where results from a laboratory study and two field studies where synthesized.  UV-degradation of macroplastic litter (a bag, wrapper, cup lid, and bottle) into MP was studied in a laboratory experiment, highlighting one of the sources of MPs in urban environments. MPs generated using accelerated UV-degradation with three exposure times (corresponding to ¼, 1 and 2 years outdoors in Sweden) were quantified with micro-Fourier Transform Infrared Spectroscopy (µFTIR). In the field studies sediment samples were collected form 29 gully pots and six stormwater ponds in urban areas in Sweden, in order to investigate MP composition and concentrations. All sediment samples were analysed with regards to MPs (non-carbon black) using µ-FTIR, enabling the assessment of MP concentrations by number, mass as well as particle size. Using the same method (µFTIR) enabled comparison of the results between the laboratory and field studies. As a complement carbon-black MPs were analysed in gully pot sediments and TWPs in pond sediments using Attenuated Total Reflection (ATR)-FTIR and Pyrolysis-GC-MS respectively.   MPs were detected in all sediment samples, indicating that both gully pots and ponds temporarily trap MPs through sedimentation, thus they were not transported further downstream. Polypropylene (PP), EPDM (gully pots) and TWPs (ponds) were among the most commonly detected polymer type in sediment samples. The laboratory study showed that common plastic litters degrade due to UV- exposure (with the PP- wrapper being most prone to degradation), highlighting PP as a possible source of MPs in stormwater. The majority of (non-black) MPs, by number, were in the size range 126 - 250 µm in gully pot sediments, in contrast to pond sediments the majority were smaller than 100 µm. These results indicates that larger MP particles tend to settle early in the urban drainage system for example in gully pots, while smaller particles may be transported further downstream via stormwater, for example reaching ponds and mainly settle in pond sediment  Evaluating MP concentrations and composition with regards to polymer type and particle size in gully pot and stormwater pond sediments and common sources one of the source of MPs in the urban environment has advanced the understanding for example a commonly detected type (PP) and what MP sizes that tend to settle in the different studied storm water management facilities i.e., gully pots and ponds.

Introduction: The widespread presence of plastics in our environment poses a growing concern as they may pose risks to human and environmental health. Microplastics (MPs) are small particles generated through fragmentation of larger plastic items. The presence of MPs particles has been reported in the human placenta, an organ essential for pregnancy and fetal development. The presence of MP contamination of the womb raises the possibility of adverse effects on the developing fetus with potential life-long consequences. This thesis seeks to investigate this issue through: 1) A review aimed to examine the current state of knowledge on the effects of exposure to MP on maternal and fetal health within the DOHaD framework; 2) A study conducted to confirm and further the reports of microplastics in human placentas through a study, in a Canadian setting, comparing MPs exposure to delivery methods. Methods: 1) A review was conducted of the current literature on microplastic contamination in human reproductive tissues, and the resulting reproductive consequences of exposure. 2) Placentas (n=10) were collected from singleton, uncomplicated pregnancies. Placentas were collected from vaginal (n=5) and cesarean section (n=5) deliveries within a plastics-reduced clinical setting. Placental tissue biopsies were micro-dissected under plastic-reduced conditions - from basal plate, chorionic villous and chorionic plate. Samples were chemically digested and filtered through glass microfiber filters and the retained particles were identified and characterized using Raman microspectroscopy. iii Results: 1) The review reports multiple lines of evidence that suggest that MP-exposure prior to or during pregnancy can contaminate various internal tissues (including those of the fetus) and may result in potential adverse effects on fertility, fetal development and long-term health of the exposed fetus. More importantly, the available evidence is limited and several significant gaps in knowledge were identified. 2) Microplastics composed of various polymer types were detected in placentas from both delivery types (vaginal or caesarian), with polyethylene being the most common. In addition, non-plastic foreign particles including graphite, lead oxide and black carbon were observed in a higher frequency than microplastics. Notably, both microplastic and non-microplastic particles were found in all placentas sampled with variations in the number of particles. Particles both plastic and non-plastic were observed in placenta regions of maternal and fetal circulation suggesting that these can pass through the placenta into fetal tissues. Conclusion: This thesis provides evidence that the human placenta can serve as a reservoir for the accumulation of a variety of foreign particles during pregnancy. The potential human health impacts of such particles in general or on fetal development, in particular, are unknown but is a critical question for future work to understand the health consequences of plastic pollution.

Microplastics (MPs) pollution is a global ongoing issue in freshwater ecosystems. The threat of MPs has only recently been recognized and research is needed to better understand how widespread this threat is. Plastic litter is the ultimate source of MPs and we might therefore expect MPs to be a greater threat in areas of high human use. To improve our understanding of how MPs pollution might vary with human land use, we will survey for MPs in freshwater streams. To find the variation of land use this study would be sampling three major types of streams: forested, urban, and agricultural. MPs will be sampled from three streams in each landscape using 1 L grab samples. The freshwater will be filtered and MPs in each landscape will be compared using ANOVA. Each stream site will be sampled five times for a total of forty-five grab samples. The samples will take place in early spring, and sampling after a storm will be avoided to prevent bias data. The results of the project will improve our understanding of where MPs are a potential threat in East Tennessee, as well as our broader understanding of how human activity influences the distribution of this threat.

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In Sweden exist about 1200 artificial turfs. Artificial turfs contain a layer of rubber granulates, which counts as microplastics and can emit to the environment. The emitted amount is uncertain but estimated to 475 tons/year. According to Swedish environmental code, artificial turfs can be classified as an environmental hazardous activity and the operators have a responsibility to reduce emissions. The purpose of this study was to investigate the work being done to reduce microplastic emissions from artificial turfs operated by Sweden’s municipalities and how it relates to the general rules of consideration in the environmental code. A web-survey was sent to all municipalities in Sweden. The result indicated that there is a high level of awareness of the problem among the municipalities. 68% have identified pathways for rubber granulates from the artificial turfs to the environment. Most common identified pathways were players, via stormwater and snow clearance. 87% have taken protective measures to reduce emissions. Most common measures taken were hard surface around the turf, granulate traps/filter in stormwater wells and collection areas for snow. Some municipalities are also testing and investigating alternative infill material. A majority were aware of the Swedish environmental protection agency’s guidance. The general rules of consideration were applicable to reduce emissions of microplastic. The reuse of rubber granulates when refilling the turfs and the investigation for alternative infill material could increase. Knowledge and insight among the operators, players and maintenance are key factors to limit the emissions along with proper protective measures.

Excessive release of nitrogen (e.g., ammonia and organic nitrogen) into natural water systems can cause serious environmental problems such as algal blooms and eutrophication in lakes and rivers, threating the aquatic life and ecosystem balance. Membrane aerated biofilm reactor (MABR) and anaerobic ammonia oxidation (Anammox) are new technologies for wastewater treatment with an emphasis on energy-efficient nitrification and denitrification. Microplastic (MP) is an emerging contaminant in wastewater and sludge treatment that has a negative effect on the environment and public health. For these relatively new technologies and contaminants, mathematical models can enhance our understanding of the removal mechanisms, such as reaction kinetics and mass transport. In this study, mathematical models were developed and utilized to simulate the removal of nitrogen and MP in biological reactions in wastewater treatment processes. Firstly, a comprehensive MABR model was developed and calibrated using a pilot-scale MABR operation data to estimate the important process parameters where it was found that biofilm thickness, liquid film thickness and C/N ratio are key parameters on nitrification and denitrification. Secondly, a mathematical model for Anammox process was developed and calibrated using previous experimental results to simulate the wastewater treatment using Anammox process, reflecting the importance of dissolved oxygen on the nitrogen removal using Anammox bacteria. Thirdly, a granule-based Anammox mathematical model was built and calibrated using other simulation results from previous Anammox studies, showing the significance of operational conditions (e.g., granule diameter and dissolved oxygen) on the success of Anammox enrichment process. Fourthly, an enzyme kinetic mathematical model was constructed and calibrated with lab-scale experiments to simulate the MP reduction using hydrolytic enzymes under various experimental conditions where it was found that anaerobic digesters can be an innovative solution for MP removal during the wastewater treatment processes. Based on the main findings in this study, it can be concluded that mathematical models calibrated with various experimental results are efficient tools for determining the important operational parameters on the nitrogen and MP removal and helping in the design and operation of large-scale removal applications. / Thesis / Doctor of Philosophy (PhD) / Nitrogen and microplastic (MP) are serious contaminants in wastewater that can cause critical environmental and public health problems. Nitrogen can cause algal blooms, threatening the aquatic ecosystem while MP can be ingested by the biota (e.g., fish and seabirds), causing serious damage in the food chain. Nitrogen removal in the conventional biological wastewater treatment is relatively expensive, requiring high energy cost and large footprint for the wastewater treatment facilities. MP removal is also difficult in the conventional wastewater and sludge treatment processes. Therefore, new technologies, including membrane aerated biofilm reactor (MABR), anaerobic ammonia oxidation (Anammox) and hydrolytic enzymes processes, are implemented to improve the nitrogen and MP removal with a reduced energy and resources consumption in wastewater and sludge treatment processes. Numerical models are considered as an efficient tool for better understanding of these novel technologies and the competitive biological reaction in these technologies coupled with accurate estimation of process rates of the reactions. In this thesis, different numerical models were developed and calibrated to estimate the important model parameters, assess the effect of operational conditions on the removal mechanisms and determine the dominant parameters on the removal of nitrogen and MP in the wastewater treatment processes. These numerical models can be used for better understanding of the removal mechanisms of nitrogen and MP, helping in the design and operation of removal systems and addressing novel technologies in large-scale nitrogen and MP removal applications.

No description available.