Quantification and composition analysis of plastic pollution in riverine beaches of the lower Parana River, Argentina

Plastic pollution and the numerous consequences it has on aquatic life have become a huge concern in recent years. While many studies have been conducted in marine environments, studies in freshwater ecosystems are scarce and insufficient. The Parana River is the most important water course in the La Plata River basin and the fifth in the world with a mean annual discharge of 18,000 m(3) per second. Currently available studies show the presence of plastic in river shores and fish gut, but more research should be carried out in order to know the extension and origin of plastic contamination. Therefore, the aim of this study was to quantify and characterize macro-, meso-, and microplastics found in the riverine beaches next to Rosario city, the most populated city standing by the lower Parana River coast in Argentina. The results show that plastic pollution is ubiquitous, but the city shores are significantly more polluted than the wetland shore with a mean of 30,780 and 6375 microplastics per square meter respectively (p = 0.024). The food and beverage industry packaging combined were the most frequent macroplastics found. Also, 3 out of 4 meso- and microplastics were white/transparent, the color that is most likely to be ingested by fish and invertebrates. Finally, all micro- and mesoplastics found were secondary and, in the case of microplastics, they were mainly fibers (93.4%) which highlight its ecological relevance. As a whole, plastic contamination is a serious issue in the Rosario area, specially single-use plastics and short-lived products. The anthropic effect of the cities and how it contributes to plastic pollution are evident.

Automated summary

Plastic pollution is a serious issue in the Rosario area, with city shores significantly more polluted than wetland shores. The food and beverage industry packaging is the most frequent macroplastic found, while the majority of meso- and microplastics are white/transparent, increasing the likelihood of ingestion by fish and invertebrates. The study highlights the ecological relevance of secondary microplastics, particularly fibers, in the riverine beaches next to Rosario city.