Following the fate of microplastic in four abiotic and biotic matrices along the Ticino River (North Italy)

Caddisfly Larvae are a Driver of Plastic Litter Breakdown and Microplastic Formation in Freshwater Environments

“…A lighter case may have both negative and positive consequences for the larvae; whereas heavier cases can provide greater stability in water currents (Delgado & Carbonell, 1997 ; König & Waringer, 2008 ), successful prey capture was found to be significantly greater in larvae inhabiting lighter cases (Otto, 1987 ). Determining plastic ingestion by larvae was beyond the scope of our study, but given the extent of chewing, the large number of microplastics formed by some larvae, and the known ingestion of microplastics by caddisfly larvae (López‐Rojo et al, 2020 ; Windsor et al, 2019 ; Winkler et al, 2022 ), a degree of plastic ingestion would not be unexpected and has the potential to cause considerable adverse effects (López‐Rojo et al, 2020 ). Furthermore, even if microplastic ingestion did not occur, interactions with harmful chemicals often associated with plastics, such as phthalates, persistent organic pollutants, and toxic metals (Rochman, 2015 ), could pose an exposure risk to larvae during plastic fragmentation and during their prolonged interaction with the plastic after its incorporation into their cases.…”

Microplastic pollution in small rivers along rural–urban gradients: Variations across catchments and between water column and sediments

“…This is most likely due to precipitation. It is known, that the MP concentration in rivers increases with the amount of precipitation and flow velocity (Gündoğdu et al, 2018;Winkler et al, 2022), which is due to the resuspension of plastic particles from river sediments and river banks. This is also supported by the observation that the sampling sites with the lowest MP concentrations in the surface water samples had the highest concentrations in the sediment samples (Winkler et al, 2022).…”

“…It is known, that the MP concentration in rivers increases with the amount of precipitation and flow velocity (Gündoğdu et al, 2018;Winkler et al, 2022), which is due to the resuspension of plastic particles from river sediments and river banks. This is also supported by the observation that the sampling sites with the lowest MP concentrations in the surface water samples had the highest concentrations in the sediment samples (Winkler et al, 2022). The findings of our and previous studies suggest that the hydrogeomorphology of the river studied is important for the MP distribution, indicating the need for further studies that take into account both spatial and temporal variability and carefully designing the sampling campaign.…”

“…These results are in agreement with the review paper by Yang et al (2021): they reported that PE was the main polymer type identified, followed by PP and PS, but also emphasised the diversity of MPs found in different regions of the world. For example, ethylene-co-vinyl acetate (EVA) was the main polymer found in the Ticino River (Winkler et al, 2022). On the contrary, Yang et al (2021) reported that fibres were the most commonly occurring particles in freshwater sediments; however, it is important to note that the results of many studies may have been erroneous, as fibres were usually of natural origin (semi-natural fibres, most likely cotton) (Stanton et al, 2019).…”

“…Flow conditions (flow velocity, flood events) and particle properties (shape, density, type of material, microbial overgrowth) are the most important factors controlling the transport of individual MP particles in rivers (Horton and Dixon, 2018;Waldschläger et al, 2020;Winkler et al, 2022). Depending on their density, particles can either float or sink when introduced into the water (Waldschläger and Schüttrumpf, 2019).…”