PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article An Experimental Study on Microplastic Settling Velocities in Different Water Environments: Which Factors Shape the Settling Process(Pergamon-Elsevier Science Ltd, 2025) Alpergun, Cumana; Alyuruk, Nefise; Baycan, Neval; Gunduz, OrhanUnderstanding the behavior of microplastics in aquatic environments is crucial, given their widespread presence and potential ecological impact. This study investigated the effects of biofilm formation and weathering processes on the settling rates of microplastics across different water matrices. To this end, nine different polymer types were examined in four distinct conditions-pristine, biofilm-coated, aged, and biofilm-coated after weathering-across three defined size categories. A total of 648 experimental results representing different conditions were analyzed. The results revealed that the settling velocities of microplastics ranging from 0.5 to 4.5 mm varied between 0.012 and 0.154 m/s. Polybutylene terephthalate and polyethylene terephthalate particles exhibited the fastest settling rates (0.154 and 0.145 m/s), whereas acrylonitrile butadiene styrene showed the slowest (0.012 m/s). Although microplastic density and size were found to be significant factors of settling velocity, water matrix, biofilm formation, and weathering processes did not show a statistically significant difference under the conditions of this study. This was related to insufficient time for biofilm growth, limited structural changes due to weathering, and the controlled laboratory environment. Biofilm formation was observed to be more pronounced on rough and matte surfaces, while it was less prominent on shiny and slippery surfaces. Additionally, it was determined that weathering alters surface morphology and potential adsorption capacity, which plays a critical role in the environmental interactions of microplastics. Furthermore, the experimentally determined settling velocities were compared with theoretical estimations obtained using two different models from the literature. A comparison between the experimental settling data and theoretical models demonstrated a strong alignment with the models proposed by Waldschla<spacing diaeresis>ger and Sch & uuml;ttrumpf (2019) and Akdogan and Guven (2024), particularly for microplastics with irregular shapes. These results suggest that such theoretical approaches can reliably predict the settling behavior of specific polymer types. Overall, the findings underscore the practical applicability of these models for estimating the transport and fate of microplastics in natural aquatic systems, offering a valuable foundation for future environmental assessments.Article Citation - WoS: 3Citation - Scopus: 3Analysis of Microplastic Flux From the Gediz River To the Aegean Sea: a Modeling Study for Environmental Management(Academic Press Ltd- Elsevier Science Ltd, 2025) Kazanci, Yigithan; Alyuruk, Nefise; Alpergun, Cumana; Kara, Nursena; Baycan, Neval; Gunduz, OrhanIt is critical to determine the abundance of microplastics in terrestrial inland waters, understand their fate and transport mechanisms, and reveal their status in aquatic environments. This study aimed to develop and calibrate a mathematical model to simulate microplastic (MP) pollution in the Gediz River Basin, T & uuml;rkiye, which focused on MP fate and transport under existing conditions and various management scenarios. The baseline scenario revealed that, despite a ninefold difference in flow rates, the midstream and upstream parts of the basin also exhibited significant contamination, with an average concentration of 25 n/L compared to the downstream average of 29 n/L. The model was later simulated to test the effects of various mitigation scenarios including but not limited to reducing MP discharges from wastewater treatment plants (WWTPs) and implementing vegetative barriers in tributaries. Scenario 4, which involves reducing MP concentrations in upstream tributaries with vegetative barriers, achieved the highest average reduction across all segments (32 %) and specifically in the downstream area (47 %). In contrast, Scenario 1, aimed at reducing wastewater discharges from urban and industrial WWTPs through water reclamation, and Scenario 2, which focused on eliminating MP in Organized Industrial Zone (OIZ) discharges by changing industrial inputs, achieved the most effective MP reductions in the upper basin, with reductions of 20 % and 17 %, respectively. Scenario 3, targeting flow reduction and accumulation through constructed wetlands, had minimal impact, with reductions close to 0 % in most areas. These results highlight the need for comprehensive approaches to effectively reduce MP pollution, particularly in managing upstream and tributary sources.
