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    Assessing microplastic pollution in a river basin: A multidisciplinary study on circularity, sustainability, and socio-economic impacts
    (Academic Press Inc Elsevier Science, 2024) Tavsanoglu, Ulku Nihan; Koraltan, Idrisdris; Kankilic, Gokben Basaran; Cirak, Tamer; Erturk, Seyma; Urker, Okan; Guclu, Pembe
    Plastic pollution has emerged as a significant environmental challenge worldwide, posing serious threats to ecosystems and human health. This study seeks to explore the interplay among circularity, sustainability, and the release of microplastics within the freshwater ecosystems situated along the western Black Sea coast- D & uuml;zce, T & uuml;rkiye. Employing a multidisciplinary approach that integrates environmental science, economics, and policy analysis, the research examines the current state of plastic pollution in the region, considering diverse land uses and socio-economic lifestyles. Conducted over four different seasons, the current study identifies the prevailing types of microplastics in the region. Fibers dominate, comprising 86.7% in each season, followed by film and fragments at 7.7% and 7.0%, respectively. Notably, polyethylene (PE) and polypropylene (PP) emerges as the primary polymer types. The distribution of polymer types varies across different land uses within the region, emphasizing the influential role of land use in shaping the abundance polymer composition. The comprehensive assessment of pollution, as reflected in the overall pollution load index (PLI) of the Melen River indicating a concerning level of pollution (PLI>1). Finally, the study unveiled the relationship between socio-economic activities as well as the seasonal precipitation patterns, and microplastic contamination in the region. This underscored the importance of site-specific mitigation measures on reducing the amount of microplastics. Lastly, incorporating sustainable practices within the circular economy framework fosters a harmonious balance between economic development and environmental protection in T & uuml;rkiye.
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    In vitro and in vivo effects of commercial and environmental microplastics on Unio delicatus
    (Springer, 2024) Yuce, Pinar Arslan; Gunal, Aysel Caglan; Erkmen, Belda; Yurdakok-Dikmen, Begum; Cagan, Ali Serhan; Cirak, Tamer; Kankilic, Gokben Basaran
    Microplastics (MPs) are ubiquitous pollutants in freshwater environments. In this study, freshwater mussels, Unio delicatus, were exposed to both environmental MPs (e-MP) and commercial MPs (c-MP) that include green fluorescent MP (gf-MP), polyethylene (c-PE) and polystyrene (c-PS) at environmental concentrations (5 mg/L and 50 mg/L) over duration of 7 and 30 days. According to in vivo experiment results, both e-MPs and c-MPs induced significant changes in the total hemocyte counts of mussels (p < 0.05). Exposure to high concentrations of e-MPs and c-MPs for 7 days led to decreased cellular glutathione levels in the mussels, while exposure to low concentrations of e-MPs and c-PS for 7 days resulted in increased advanced oxidation protein products (AOPP). Mussels exposed to high concentrations of e-MPs for 30 days exhibited decreases in both glutathione levels and AOPP values. Although no damage was observed in tissues other than gills and digestive gland, histopathological alterations were observed in these tissues following exposure to 50 mg/L c-MPs. Additionally, MPs were observed in the intestine tissues. In vitro experiments using the MTT assay showed no significant difference in cell viability between the MP-exposed group and the control group at tested concentrations, with no observed dose-response relationship (p > 0.05). Nevertheless, certain cells exhibited signs of cell death, such as disrupted cellular structures, condensed nuclei, and loss of cellular integrity. These observations were consistent with mechanical compression, indicating that physical contact with MPs may result in cell damage or death. These findings demonstrate that environmentally relevant concentrations of MPs have toxic effects on freshwater mussels and multiple parameters provide valuable insight for the evaluation of health risks of organisms.
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    Microplastics in a dam lake in Turkey: type, mesh size effect, and bacterial biofilm communities
    (SPRINGER HEIDELBERG, 9999) Tavsanoglu, Ulku Nihan; Basaran Kankilic, Gokben; Akca, Gulcin; Cirak, Tamer; Erdogan, Seyda
    The evaluation of microplastic (MP) pollution has been drawing attention for the last decades. MP pollution has been studied widely in marine environments, but limited data exists for freshwater ecosystems on potential source and transport of MPs. The type, shape, plastic components, and the color of the MPs were investigated using various-mesh-sizes (300 and 100 mu m) nets in four sampling stations of Sureyyabey Dam Lake in Turkey. The growth of bacterial isolates on the MPs surface and surrounding water was also investigated. The type of the MPs and the interaction between the mesh size and the type of the MPs showed significant differences (p < 0.05). Fibers were found to be the most abundant particle type constituting 45% and 80% of the total MPs found in 330-mu m and 100-mu m mesh sizes, respectively. In total the observed MP abundance in the dam lake was 5.25 particles m(-3), and 4.09 particles m(-3)was observed for 100-mu m and 330-mu m mesh sizes, respectively. The color of the identified microplastics showed variations among microplastic types; however, the dominant color was transparent in each net. The main plastic components of the MPs are polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, and polypropylene. The microbial community mainly consists of potentially pathogenic strains such asEscherichia coli,Enterococcus faecalis, andAcinetobacter baumanii complex.The current study could contribute valuable background information both for MP pollution and for biofilm composition in a dam. However, the surface of the MPs and biofilm formation should be investigated urgently to understand the vector potential of MPs.
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    Targeted delivery of etoposide to osteosarcoma cells using poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles
    (Tubitak Scientific & Technical Research Council Turkey, 2017) Alp, Esma; Cirak, Tamer; Demirbilek, Murat; Turk, Mustafa; Guven, Eylem
    Folic acid (FA)-functionalized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles were prepared to enhance the delivery efficiency of the anticancer drug etoposide for the clinical treatment of osteosarcoma. PHBV nanoparticles were synthesized by emulsification/solvent evaporation technique and obtained in the size range of 200-250 nm and zeta potential range of -21 and -27 mV. Encapsulation efficiency and in vitro drug release were studied. The cytotoxic, apoptotic, and necrotic effects of PHBV nanoparticles were also investigated using Saos-2 osteosarcoma cells. The results obtained in this study demonstrate that etoposide-loaded and FA-functionalized PHBV nanoparticles can be successfully used for targeted treatment of osteosarcoma.