Massive plastic pollution in a mega-river of a developing country: Sediment deposition and ingestion by fish (Prochilodus lineatus)

Abstract

The aim of this study was to determine the amount, composition and origin of plastic debris in one of the world largest river, the Paraná River in Argentina (South America), focusing on the impact of urban rivers, relationships among macro, meso and microplastic, sociopolitical issues and microplastic ingestion by fish.We recorded a huge concentration of macroplastic debris of domestic origin (up to 5.05 macroplastic items per m 2 ) dominated largely by bags (mainly high-and low-density 2 polyethylene), foodwrapper (polypropylene and polystyrene), foam plastics (expanded polystyrene) and beverage bottles (polyethylene terephthalate), particularly downstream from the confluence with an urban stream. This suggests inadequate waste collection, processing and final disposal in the region, which is regrettably recurrent in many cities of the Global South and Argentina in particular.We found an average of 4654 microplastic fragments m -2 in shoreline sediments of the river, ranging from 131 to 12687 microplastics m -2 . In contrast to other studies from industrialized countries from Europe and North America, secondary microplastics (resulting from comminution of larger particles) were more abundant than primary ones (microbeads to cosmetics or pellets to the industry). This could be explained by differences in consumer habits and industrialization level between societies and economies.Microplastic particles (mostly fibres) were recorded in the digestive tract of 100% of the studied Prochilodus lineatus (commercial species).Contrary to recently published statements by other researchers, our results suggest neither macroplastic nor mesoplastics would serve as surrogate for microplastic items in pollution surveys, suggesting the need to consider all three size categories.The massive plastic pollution found in the Paraná River is caused by an inadequate waste management. New actions are required to properly manage waste from its inception to its final disposal. CAPSULEMassive plastic pollution in a mega-river from Argentina, mainly caused by inadequate waste management.

Macroplastic Storage and Remobilization in Rivers

“…Previous works on surface and subsurface storage of macroplastic debris used hand collection and sieve analysis for an estimation of plastic abundance (Table 1). Analysed samples were collected from quadrats [30,34,62,63], circles [64] or transects [65] delimited parallel or perpendicular to the shoreline of the river channel or reservoir [59]. Obtained results were usually described as number of plastic debris items or their mass per surface area (m 2 ) of sampled plot (Table 1), which is useful for estimation of plastic abundance in contemporary surface sediments, but does not allow for a reliable comparison with volumetric samples of sediments taken from cores or riverbanks.…”

“…Calculation of the abundance of macroplastic debris in sediment volume could also be useful in future studies utilizing samples taken from sediment cores or riverbanks. The volumetric method of sample collection may be implemented using existing approaches (e.g., [62,64]), making it possible to study the abundance of plastic debris in deposits of contemporary fluvial forms (e.g., channel bar, floodplain, island), and to compare this abundance with similar older deposits. Such an approach could also enable estimation of the total amount of plastic stored in a given river section or a whole river system, which is of crucial importance for a reliable estimation of the potential for its future remobilization by lateral migration of river channel.…”

“…items/site kg/site types (%) of items/site items/collection/100 m [62] Riverbank. Surface and subsurface sediments.…”

The Way of Macroplastic through the Environment

“…Sampling at the banks of five different rivers in Nigeria has shown high levels of MaP contamination, with 3487 waste items/m 2 (>5 cm), 59% of which were MaP [133]. Along the Paranà River in Argentina, the average MaP abundance was 5.05 items/m 2 [134]. With the use of crowd-based observations, van Emmerik et al (2020) [9] estimated for the riverbanks of the Rhine River (The Netherlands, downstream stretch) a concentration of 573-1033 items/km with an increase towards the estuary.…”

Natural Resource Conservation Based on Community Economic Empowerment: Perspectives on Watershed Management and Slum Settlements in Makassar City, South Sulawesi, Indonesia

“…Erosion in advanced stages can not only transport sediments but also remove nutrients, organic carbon and agrochemical contaminants to outside the systems, resulting in a decrease of overall land productivity [49]. Furthermore, increasing pollution and decreasing environmental quality can be explained based on consumer habits and the level of industrialization between the community and the economy as well as due to inadequate waste management [50]. Conservation efforts are needed through controlling spatial use by limiting the development of slums along the Tallo watershed.…”