Aquatic environments are one of the final destinations for microplastics. In this review, a combination of systematic and narrative literature review was conducted to identify and summarise advances, gaps, and future directions in microplastic monitoring studies in the Turkish aquatic environment and in inhabiting aquatic organisms. A total of 62 peer-reviewed publications available on Web of Science were considered in the systematic review. Additionally, the current state of microplastic pollution in Turkish aquatic environments which includes marine and freshwater ecosystems, as well as aquatic organisms, and sources and characteristics of microplastics were reviewed narratively. Türkiye`s position on the global plastic treaty and mitigation practices were also addressed. Although an increase in the number of publications over time was observed, the number and extent of studies carried out in freshwater ecosystems are limited. Strict legislation should be enacted and enforced to tackle plastic pollution in Türkiye. Additionally, nationwide, long-term monitoring studies at sufficiently regular intervals in aquatic environments should be considered.

Rivers are critical pathways of microplastic (MP) pollution to marine environments, yet their contributions to the Black Sea remain understudied. This study evaluates the abundance and characteristics (polymer composition, shape, size, and color) of MPs discharged from 29 rivers flowing into the southern Black Sea. Using a plankton net with a 200 μm mesh size, samples were collected from river mouths, revealing an average MP abundance of 9.63 ± 1.27 MP m⁻³, ranging from 1.03 to 29.8 MP m⁻³. Eastern Black Sea rivers exhibited significantly higher MP levels (11.0 ± 1.57 MP m⁻³) compared to western rivers (5.15 ± 1.25 MP m⁻³). Annual MP discharge to the Black Sea was estimated at 1.49 × 10¹¹ particles. Polyethylene terephthalate (PET, 59.3% ± 2.66%), polyethylene (PE, 20.8% ± 2.04%), and polypropylene (PP, 14.1% ± 2.36%) were the most common polymers, with PET and PE being significantly dominant. MP sizes ranged predominantly between 200–1000 μm, and fibers constituted the majority of shapes (64.1%), followed by fragments (28.3%). White (36.8% ± 1.93%) and transparent (30.9% ± 2.39%) MPs were the most prevalent colors. While no significant differences in MP characteristics were detected between basins (NMDS and ANOSIM), this study emphasizes rivers as major pathways for MP pollution in the Black Sea. These findings underscore the urgent need for targeted mitigation strategies to safeguard marine ecosystems and biodiversity.