No Seasonal Differences in the Emission of Microplastics from an Urban Wastewater Treatment Plant on the Southern Coast of the Caspian Sea

Document Type : Original Research Paper


1 Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran

2 Department of Ecological Science, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan


This paper is the first to report on the role of a wastewater treatment plant (WWTP) in Sari, as a source of microplastics (MPs) in the Caspian Sea. Composite 270-liter/24-hour samples were taken the treated effluent of the WWTP in winter and spring, two seasons with different levels of human activity. The effluent contained 380±52.5 and 423±44.9 MPs/m3 in winter and spring, respectively, with the total numbers of MPs/m3 not differing between the two seasons. The dominant type of MPs in the effluent was microfibers with 237±68.7 and 328±33.4 per m3 in winter and spring, respectively. In both seasons, fiber sizes of


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