Macroplastic pollution in riparian corridors of urban and pristine mountain streams in Patagonia (Argentina)

ANDRADE-MUÑOZ, ALAN SEBASTIÁN; MISERENDINO, MARÍA LAURA; QUINTEROS, CLAUDIA PAMELA; DROMAZ, WALTER MAURICIO; ABRIAL, ELIE; DI PRINZIO, CECILIA YANINA

THE SCIENCE OF TOTAL ENVIRONMENT

ELSEVIER

Año: 2025 vol. 959

0048-9697

Plastic pollution has garnered much more attention in marine environments, while scientific research on freshwater and terrestrial ecosystems has been relatively overlooked. Numerous studies worldwide have highlighted the presence of macroplastics (>2.5 cm) in mountain riverine environments, revealing that even these seemingly pristine ecosystems are not invulnerable to plastic contamination. We investigated the composition and spatial variation of macroplastic debris in the riparian corridors of nine watercourses in Patagonia. Four types of river reaches were assessed: Reference (without urbanization), Upstream-Urban, Urban, and Downstream-Urban, each with varying degrees of urbanization. We analyzed the intrinsic characteristics of the plastics (manufacture and resin type) and environmental factors with possible incidence in plastic distribution (geomorphology, land use, riparian vegetation quality, and climate) during the Southern Hemisphere´s spring season. The most abundant macroplastic debris originated from domestic sources, primarily bags (high- and low density polyethylene), food wrappers (polypropylene), and beverage bottles (polyethylene terephthalate). The number of inhabitants and proximity to urban areas were the strongest drivers of riverside litter accumulation. Climatic variables such as wind speed and rainfall have incidence in macroplastic abundance, but other factors, such as river discharge possibly played a role in their mobilization. Macroplastics number positively correlatedwith urban area and negatively with non-woody vegetation. The quality of the riparian corridor, as measured by the QBRp index, had low explanatory power for litter accumulation. Lower QBRp scores were associated with a high number of macroplastic items suggesting that vegetation played a limited role in trapping litter, possibly because urban reaches were heavily anthropized. This study highlights the importance of identifying critical areas of litter accumulation on riverbanks. Our findings provide a foundation for developing strategies to mitigate plastic pollution, improve waste management, and raise public awareness about the challenges of macroplastic contamination and its proper disposal in Patagonia.