Occurrence, Abundance and Characteristics of Microplastics in the Sediments of the Zayandeh- Rud River

One of the most important emerging pollutants in aquatic environments that has recently attracted the attention of global researchers is plastic waste, especially microplastics. This study aimed to investigate the occurrence, and abundance and characteristics of microplastics in 21 stations in the Zayandeh-Rud River. The average abundance of microplastics was 70.481±29.39 particles in 50 gr/dry sediment. Station 17 with an average number of 363.50±14.849 particles and stations 1, 6 and 7 with an average number of 1.528±1.33 particles in 50 gr/dry sediment had the highest and lowest levels of pollution, respectively. The size of all microplastics was in the range of 50-5000 micrometers. Microplastics less than 500 microns were the most abundant with 64.5%. The dominant form of microplastics with the frequency of 34.9%, 33% and 28.8% belonged to line, fragment, and fiber, respectively. In total, 4 polymers, polypropylene, polyamide, polyurethane, and polyethylene, were identified. The results show that human activities, including the discharge of urban and industrial wastewater also plastic waste by tourists on the river, play an important role in microplastic pollution in this area. Therefore, developing a program to monitoring microplastics in the water and sediment of Zayandehroud River will be of great help for management measures to control this pollution.