Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Microplastic Pollution and Risk Evaluation in the Gediz River(Central Fisheries Research inst, 2026) Baycan, Neval; Alyuruk, Nefise; Kazanci, Yigithan; Alpergun, Cumana; Kara, Nursena; Gunduz, OrhanMicroplastics (MPs), particles less than 5 mm in diameter, enter the aquatic ecosystem through the degradation of larger plastics. They can accumulate in the environment for long periods due to their durability and buoyancy. In this study, a risk assessment of MPs was conducted at five different stations in the Gediz River via a Pollution Load Index (PLI) and a Polymer Hazard Index (PHI) calculated for dry and wet seasons to highlight the risks caused by seasonal variations of pollution levels for different types of MPs in an urban river discharging to Izmir Bay. The results showed that MPs were widespread in the area, with an average abundance of 13-211 units/L/L. During the dry season, the mean number of particles was 67 +/- 57; during the wet season, the mean number of particles decreased to 50 +/- 37. The most common type was polypropylene with 62.4%, followed by Polyethylene and Polyethylene Terephthalate (8.3% and 7.01%). The most abundant MP shapes are fragments and fibers, with 47.1% and 38.5%. During the dry season, PLI values ranged from 0.99 to 2.44, while in the wet period, they ranged from 1.08 to 2.11. Furthermore, PHI values for the MP species detected at each station ranged from 3.81 to 7.91. The results indicated that the Gediz River is a significant MPs source for Izmir Bay and demonstrates a major hazard for its overall ecological condition.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.