Preliminary Assessment of Plastic Litter and Microplastic Contamination in Freshwater Depositional Areas: The Case Study of Puerto Misahualli, Ecuadorian Amazonia

We quantify plastic litter (PL, > 2 cm) and microplastics (MP, < 5 mm) from the sediments of a beach formed at a riverine depositional area, at the upper Amazon River basin, Ecuador. In the collection area (4400 m²), the PL density was 0.045 items m⁻², where low-density polyethylene bags were the prevalent PL. The beach was classified as “very clean” (Clean Coast Index (CCI) of 1.3 items m⁻²). Regarding MP, in 55 sampling stations, average MP concentrations ranged from 0 to 2200 items kg⁻¹ of dry sediment (0.5–2 mm), and 0–4200 items kg⁻¹ of dry sediment (2–5 mm). Blue fibers were the prevalent MP. Our results represent the first report to show the ubiquitous presence of PL and MP for the area. The monitoring and management of plastic disposal in freshwater beaches are necessary, as here we report a small part of an undocumented issue.