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.

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.

Nowadays, plastic waste poses one of the greatest risks to the environment. Plastics affect the environment at all stages of their life cycle. Bioplastics have become widely used as a substitute for conventional plastics, without detailed examination of their behavior in real environmental conditions. As a result, it is assumed that they can accumulate in the environment and the question arose as to how to identify them. The main goal of this thesis is to develop a method based on sample pyrolysis that is suitable for the identification and determination of the amount of PLA microplastics in soil and other solid matrices. Three types of soils and sludge were used for analysis. These matrices were spiked to obtain concentration ranges 0,2% - 5,0%. The pyrolysis resulted in evolution of gases with the signals m/z 29, 43 and 44, witch originated from PLA and are suitable for qualitative and quantitative analysis. Analysis of PLA in sludge was more complicated due to similarity of gases evolved from pure matrices. We tested three approaches based on analysis of signal´s peak areas, intensities and temperatures of gas evolution. While the first approach failed, the last two approaches appeared to be promising for qualitative and quantitative analysis of PLA in the sludge. Several methods suitable for qualitative and quantitative analysis of even very small amounts of PLA in soils and sludge have also been designed/developed. These methods were based on analysis of the composition and dynamics of the released gases and the characterisctic degradation temperatures.

Plastic wastes released in the environment can produce microplastics (MPs, Size < 5 mm) and nanoscale plastics (NPs, Size < 100 nm) due to the environmental weathering processes. The presence of the MPs and NPs have been found worldwide in different aquatic and terrestrial environments. These tiny plastics have detrimental health impacts when they are ingested or inhaled by aquatic organisms as well as human beings. However, their occurrences including identification and quantification in the environment are still a great challenge. Particularly, quantification for NPs is a challenge, as there is no standard technique available yet that can count the NPs effectively. Therefore, this thesis was focused on two important aspects related to microplastics (MPs) and nanoscale plastics (NPs). Firstly, assess the source of MPs or NPs release and secondly, NPs quantification. Microfibers (MFs) are one of the most abundant portions of MPs in the aquatic environment, which are shed during the washing and drying of fabrics. Hence, in the first area of the study, the release pattern of MPs, in the form of acrylic MFs from portable washer and dryer during fabric washing and drying under different conditions were investigated. Additionally, the subsequent degradations behavior of these released MFs under ultraviolet light (UV-A) irradiation were explored. The results indicated that the MFs were released almost 2 times higher when the fabrics were washed for 60 min compared to 30 min due to higher mechanical stresses. In addition, MFs released were increased by 1.4 times higher when the fabrics were dried for 60 min compared to 30 min due to longer rotational forces on the fabrics. The use of detergent during washing promoted 2.7 times more MF release compared to without detergent. Moreover, MFs were released approximately 1.8 times higher from washing when washed with 40°C of water than with 20°C of water. However, subsequent washing cycles showed decreasing patterns of MF releases during washing and drying, approximately 45% less and 67% less, respectively in the 7th wash compared to the 1st wash as the fabrics approach a plateau. The released acrylic MFs were analyzed after their exposure to UV-A irradiation in the aquatic environment from 0 day to 182 days. After 182 days of UV-A irradiation, released acrylic MFs showed significant changes in the surface morphology in the form of cracks, holes, and flakes determined by scanning electron microscope (SEM). The formations of cracks, cavities, and flakes in the MF’s surface were proportional to the period of UV-A exposure. Dimensions of the formed holes and cracks on the UV-A degraded MFs suggested that MFs can turn into NPs in presence of water and UV-A exposure in the environment. Hence, a robust analytical tool must be optimized to detect these tiny degraded NPs in the aquatic environment. This brings to the second area of the study which aimed to optimize and validate a method to detect NPs through coating with synthesized gold nanoparticles (AuNPs) by Single Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS). This study successfully detected the polystyrene nanoscale plastics (PS NPs, size 61 nm) by particle-by-particle analysis in single quadrupole-based SP-ICP-MS and the detection limit of particle number concentration was reached up to 8.64 × 10^7 particles/L. PS NPs were selected as a model nanoscale plastic as it is one of the most abundant plastics in the environment. The method was applied to PS NPs in deionized (DI) water which achieved a good amount of PS NP recoveries by up to 98%. This analytical technique can be further optimized and might be helpful for analyzing NPs in any environmental samples to determine their occurrences and concentrations.

Analysis of seaweed as a vector for microplastics is an integral part of understanding the formation and deposition of micro-sized plastic waste in seawater. The project itself originated due to the influx of seaweed (and mismanaged plastic waste) residing on the shores of St. Kitts and Nevis and the constant deposition of plastic pollution intertwined within the seaweed. The natural occurrence of the two together lead to the consideration of fragmented plastics remaining on the seaweed. The objective of this research is to stain, identify, and quantify the concentration of microplastics sourced from both store-bought and environmental seaweed samples. A Nile red solution dissolved in either acetone or methanol was used to stain the microplastics, as per a proven method. The fluorescence of the stained microplastics was measured (excitation: 523-543 nm and emission: 580-640 nm) to identify potential dissolution. The seaweed was washed of microplastics and the solid particles collected were evaluated using infrared (IR) spectroscopy. The fluorescence and infrared spectrum results were compared to spectra within the Spectral data base system (SDBS) for the most common plastics: polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), polycarbonate (PC). The use of a fluorescence microscope allowed for direct quantification of microplastics over a specific area of the sample and therefore allowed for further identification of microplastic presence.

Microplastics are tiny particles that due to their small size, durability, and widespread usage have become a huge threat to the world and the environment. Aquatic environments like rivers and oceans have faced some irreparable problems such as the extinction of various marine species. Field sampling and numerical modeling are two methods that can help researchers have a better understanding of the situations to come up with the best solutions. Machine learning methods have drawn considerable attention in most engineering fields recently, which can be used in conjunction with field sampling and numerical simulation. In this study, by generating a fine mesh and using bathymetry, water level, and discharge data, a three-dimensional hydrodynamic modeling of the domain of study was conducted using TELEMAC 3D, which is a model that was used to simulate the behavior of the Fraser River in x, y, and z directions. The results were implemented to track the movements of microplastic particles in the lower part of the Fraser River. CaMPSim-3D, which is a three-dimensional Lagrangian particle tracking model was employed to track microplastic particles. This model, in addition to calculating the horizontal location of particles, computes their vertical movements too. The release locations of microplastic particles were chosen based on the locations of the wastewater treatment plants and combined sewer overflows and in the end, nine scenarios were conducted for this study. An unsupervised branch of machine learning is clustering which helps to cluster points by relying on their different properties. The OPTICS algorithm, which is a density-based clustering algorithm, was used to find the accumulation zones of microplastic particles in the lower part of the Fraser River. It should be mentioned that in all parts available measured data and information were used for validation. The results of the clustering algorithm indicated that there are eight accumulation zones in the study area and the breakwater in the upper branch of the Fraser River is an ideal place for microplastic particles to accumulate. A reasonable agreement was obtained between the model results and measured data.

No description available.

Plastic never fully disappears, but instead breaks into smaller pieces referred to as microplastics (< 5 mm length). Microplastics are common worldwide, and more studies are needed to understand the accumulation and diversity of microplastics found in various environments. In this study, six locations were sampled for one year in the Guana River Estuary, a partially impounded system with heavily urbanized headwaters. This study was conducted in conjunction with the Guana Tolomato Matanzas National Estuarine Research Reserve (GTM NERR) and the Florida Fish and Wildlife Conservation Commission (FWC) at their water sampling stations. The objectives of this study were to investigate: 1) distribution patterns across sample sites over time, 2) the color, size, and shape of microplastics found, and 3) polymer composition. Water samples were collected from surface waters in 1-L bottles, with five replicates at each site. Sampling occurred once a month, at the beginning of each month from August 2020-August 2021. Samples were analyzed for abundance and characteristics of microplastics using a dissecting microscope and the polymer composition was determined using Fourier-transform infrared spectroscopy. No pattern was found in the distribution of microplastics from north to south or over time. Variations in plastic color, size, and polymer composition suggests that there are multiple sources of pollution into the Guana River Estuary.

Due to the global loss of tidal marsh area, potential anthropogenic and natural disturbances to these systems, and coastal marshes’ affinity for trapping environmental pollutants, understanding how marsh birds inhabiting these ecosystems will adapt to these changes is paramount. To quantify future changes, I first needed to have something to compare against – baseline estimates. To this end, I performed distance sampling line transect surveys during the nonbreeding season to estimate species-specific population abundance, density, and habitat associations and captured two species of marsh bird, Clapper Rail (Rallus crepitans) and Seaside Sparrow (Ammospiza maritima), to estimate baseline ingestion of one such environmental pollutant – microplastics. By providing the first baseline population and density estimates for numerous nonbreeding marsh birds, my findings suggest that the tidal marshes of Mississippi provide critical habitat for many of these species. Additionally, I was able to document the first evidence of microplastic ingestion by resident tidal marsh birds.

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