Iranian Scientific Fisheries Journal

fa مقاله علمی – پژوهشی:‌ توزیع مکانی میکروپلاستیک‌ها در آب و رسوبات جزیره قشم: مطالعه موردی Microplastic distribution in Qeshm Island sediments and waters: A case study آلودگي محيطهاي آبي آلودگي محيطهاي آبي پژوهشي Research این مطالعه به صورت توصیفی به بررسی توزیع مکانی و ویژگی‌های ساختار شکلی میکروپلاستیک‌ها در نمونه‌های آب و رسوب چهار ایستگاه منتخب جزیره قشم در خلیج فارس می‌پردازد. این ذرات کوچک نه‌تنها از تجزیه پلاستیک‌های بزرگ‌تر در محیط ایجاد شده بلکه از طریق فعالیت‌های انسانی نظیر شیلات، گردشگری، شست‌وشوی منسوجات و دفع نامناسب پسماندها نیز وارد زیست‌بوم‌های آبی می‌گردند. نتایج نشان داد، فراوانی میکروپلاستیک‌ها در ایستگاه‌ها تفاوت معنی‌داری دارد به‌طوری‌که بیشترین میزان در ساحل پارک زیتون و کمترین در ساحل نقره‌ای لارک مشاهده شد. نکته قابل‌توجه این مطالعه، مشاهده غلظت بالاتر میکروپلاستیک در نمونه‌های آب نسبت به رسوب در ایستگاه هنگام بود، یافته‌ای که برخلاف بسیاری از مطالعات پیشین بوده و احتمالاً با ترکیبی از عوامل انسانی (شدت فعالیت‌های صیادی و ورود مستقیم پساب‌ها به محیط آبی)، مرتبط است. همچنین فیبرها و ذرات قهوه‌ای‌رنگ دارای بیشترین سهم در بین اشکال و رنگ‌های شناسایی‌شده بودند. یافته‌ها بیانگر آن است که فعالیت‌های انسانی و تفاوت‌های محیطی می‌توانند در توزیع مکانی مؤثر باشند و اطلاعاتی را برای پایش‌های آینده و مدیریت فراوانی انواع پلاستیک‌های منطقه فراهم کنند. Introduction In recent years, the presence of microplastics has become one of the major and emerging environmental problems in the world. These plastic particles, smaller than 5 millimeters, are formed due to the physical and chemical degradation of larger plastics or directly come from primary sources such as microbeads in cosmetic and industrial products. Because of their high durability, low density, and ability to absorb chemical pollutants, microplastics can accumulate in aquatic environments and easily move through the food chain (Browne et al., 2011; Ram and Kumar, 2020). The Persian Gulf is one of the semienclosed and sensitive marine ecosystems in the world that is strongly affected by human activities such as oil and gas industries, marine transportation, tourism, and fishing (Sheppard et al., 2010). Qeshm Island, the largest island of Iran, has faced rapid population growth, expansion of tourism and industrial activities, and a large amount of plastic waste entering its coastal areas in recent decades (Hosseini et al., 2024). Previous studies in other parts of the Persian Gulf (Naji et al., 2017; Lahijanzadeh et al., 2020; Rezaei et al., 2024) have shown that the level of microplastic contamination is directly related to population density and intensity of human activities. Although the importance of this issue is clear, few comprehensive studies have examined microplastics in both water and sediments of Qeshm Island at the same time. Therefore, the main goal of this study was to investigate the spatial distribution and morphological features of microplastics in water and sediment samples from four selected stations around Qeshm Island. The results can help to understand spatial patterns and possible sources of this pollution and provide basic data for future monitoring and marine environmental management. Focused on the abundance, spatial distribution, and morphological characteristics of microplastics in both surface water and sediment samples Emphasizes the urgent need for comprehensive monitoring programs and development of effective waste management policies in the Persian Gulf to mitigate the ecological risks posed by microplastics. Methodology This descriptive and fieldbased study was carried out in summer 2024. Four stations were chosen based on the level of human activity: Zeytoon Park Beach, Hengam, Larak Silver Beach, and Larak Shipwreck. From each station, surface water samples (1 liter) and surface sediments (0–5 cm) were collected in three repetitions. For separating microplastics, samples were treated first with 30% hydrogen peroxide and then floated using a saturated sodium chloride solution (density 1.2 g/cm³). After washing and drying at 60°C, the particles were observed under a stereo microscope and classified according to their shape (fiber, fragment, film, microbead) and color (Zhao et al., 2022). Data analysis was performed using nonparametric tests. The Kruskal–Wallis test was used to compare differences between stations, and the Mann–Whitney U test for pairwise comparison. Bonferroni correction was applied (α = 0.0083). Graphs were prepared in Excel 2024. Results The results obtained from the analysis of water and sediment samples collected from four selected stations in Qeshm Island showed that microplastic particles were present in all of the stations, and there were noticeable differences in their abundance and morphological characteristics between the areas. The average number of particles in the water samples ranged between 60 and 640 particles per liter, while in the sediments it ranged between 200 and 730 particles per kilogram. The highest abundance of microplastics was recorded at Zeytoon Park station, and the lowest value was observed at Larak Silver Beach. This difference shows the significant role of human activities in the spatial distribution of the particles. Regarding the type of particles, fibers had the highest share among all samples and made up about 54.5% of the total microplastics. After that, fragments were 16.5%, films 13%, and microbeads 16%. In the water samples, fibers were dominant and included more than 70% of the particles, while in the sediment samples, their portion was around 37%. These results are in agreement with the findings of Osorio et al. (2021) and Curren et al. (2023), who reported that fibers are the most common type of microplastic in marine environments. In terms of color, the brown particles were the most abundant, including 51% of the particles in the sediments and 37% in the water. After that, transparent, blue, and purple particles were also seen. The darker colors usually indicate that plastics have been more aged and weathered in the environment. The Kruskal–Wallis statistical test confirmed the presence of a significant difference among the stations in both water (H=10.917, p=0.008) and sediment (H=11.152, p=0.007). Also, the Mann–Whitney U test showed that Zeytoon Park station had a significant difference with the other stations (p<0.0083). These findings show that the intensity of human activities, such as tourism and fishing, has a direct effect on the spatial distribution and abundance of microplastics. Overall, the results of this study indicate that there is a considerable level of microplastic contamination in both the aquatic and sedimentary environments of Qeshm Island. They also confirm that both human and physical factors play an important role in determining the frequency and spatial pattern of these particles in the region. Discussion and conclusion The study showed that the frequency of microplastics in water and sediments of Qeshm Island is high and widely distributed. The dominance of fibers and dark colors indicates that the main sources are human activities such as fishing, washing of textiles, and urban plastic waste (Wright et al., 2021; Ramos et al., 2025). The highest frequency of microplastics was observed at Zeytoon Park, which has many tourists and higher waste accumulation. These findings are consistent with other studies in the Persian Gulf (Naji et al., 2017; Rezaei et al., 2024) and in other seas such as the Mediterranean and Caspian (Kazour et al., 2019; Mehdinia et al., 2020). The difference between water and sediment in Hengam station suggests that water currents, boat movement, and sediment texture play important roles in shaping the spatial distribution of microplastics (Akdogan et al., 2023). From a management point of view, this research highlights the need for regular monitoring, improved waste management, and education of local communities. In the authors’ opinion, these actions are very necessary for protecting the marine environment of Qeshm Island. Future studies can focus on seasonal and chemical variations of microplastics and their impacts on marine organisms and the food chain. Conflict of interest The authors declare that there is no conflict of interest in this study.   میکروپلاستیک, خلیج فارس, جزیره قشم, ساختار شکلی, محیط های دریایی Microplastics, Persian Gulf, Qeshm Island, Shape structure, Marine environment 1 12 http://isfj.ir/browse.php?a_code=A-10-2985-1&slc_lang=fa&sid=1 A. Bahrami آرزو بهرامی arezou_sia@yahoo.com 100319475328460042121 100319475328460042121 Yes University of Natural Resources and Agricultural Sciences, Gorgan دانشگاه منابع طبیعی و علوم کشاورزی گرگان، گرگان، ایران A. Mozaffari آلوینا مظفری alvinamozaffary@gmail.com 100319475328460042122 100319475328460042122 No Office of Brilliant Talents and Young Scholars, Caraj, Iran اداره استعداد های درخشان و دانش پژوهان جوان، کرج، ایران S.S. Azizmohammadi شکیبا عزیز محمدی shakibaazm4@gmail.com 100319475328460042123 100319475328460042123 No Office of Brilliant Talents and Young Scholars, Caraj, Iran اداره استعداد های درخشان و دانش پژوهان جوان، کرج، ایران