Assessing Zayandeh-Rud Coasts Pollution with Plastic Wastes Based on Clean-Coast Index

Plastic pollution is an important emerging environmental problem with possible impacts on biodiversity and human health. Although the majority of the scholarly attention in this field has been directed to oceans, plastic pollution has not been fully elucidated in freshwater ecosystems. Hence, this study aimed at investigating the spatial distribution and macro- and meso-characteristics of sedimentary plastic waste items along the Zayandeh-Rud River course. 400 types of anthropogenic debris were collected from 21 sampling sites consisting of macroplastic 58.3% (233 items), mesoplastic 18% (72 items), and other waste 23.8% (94 items). Bags (polyethylene), food packs (mainly polypropylene and polystyrene), and bottles (polyethylene terephthalate) were the dominant plastics. The Clean-Coast index was used to determine the river's cleanliness, showing that most parts of the river are clean. The Clean-Coast Index revealed useful implications in evaluating the continuity and success of protective measures such as educational, media, and enforcement actions to reduce river pollution.