Document Type : scientific research article
Authors
1
Dept. of Aquatics Production and Exploitation, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
2
Corresponding Author, Dept. of Aquatics Production and Exploitation, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
3
Dept. of Agriculture and Natural Resources, University of Applied Science and Technology, Tehran, Iran
4
Dept. of Aquaculture, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
5
Dept. of Fisheries, Faculty of Agricultural Sciences and Natural Resources, Gonbad Kavous University, Gonbad Kavous, Iran
Abstract
Gomishan Wetland, located in the southeastern Caspian Sea, is a sensitive and internationally important ecosystem in Iran, influenced by river inputs, human activities (fishing, agriculture, and tourism), and marine currents, potentially acting as a sink for microplastics.
This study aimed to investigate the presence, abundance, size, shape, color, and polymer composition of microplastics in the sediments of Gomishan Wetland. Eight sediment samples were collected from various points in the wetland. Microplastics were extracted using density separation methods and characterized by stereomicroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier-transform infrared spectroscopy (FTIR).
Results revealed microplastics in all samples, with a total of 85 particles extracted. Particle sizes were predominantly medium; 41.18% ranged from 1000–2000 μm, and over 76% were smaller than 2000 μm. Fibers dominated the shapes (70.59%), followed by fragments (18.82%) and films (10.59%). Black was the most prevalent color (62.35%), followed by white (22.35%), gray (8.24%), red (4.71%), and green (2.35%). Polymer composition included polyethylene (PE, 43.33%), polypropylene (PP, 30.00%), polystyrene (PS, 16.67%), and polyethylene terephthalate (PET, 10.00%). The distribution of these characteristics was heterogeneous across samples, indicating local influences such as hydrodynamics and pollution sources.
These findings indicate significant and widespread microplastic contamination in Gomishan Wetland sediments, dominated by black fibers and PE/PP polymers, highlighting sediments as a primary sink for emerging pollutants in this sensitive ecosystem. The results underscore the need for continuous monitoring, reduction of plastic inputs, and effective management policies to protect the wetland and its dependent food web.
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