What Are Lake Beaches Made of? An Assessment of Plastic Beach Litter on the Shores of Como Bay (Italy)

Abstract

Plastic waste dispersion is a well-recognized environmental threat, despite continuous efforts towards improving waste disposal management over the last few decades. Plastic litter is known to strongly impact upon water bodies and shorelines, affecting the health of ecosystems and impacting upon the aesthetic value of sites. Moreover, plastic waste that is abandoned on beaches contributes towards different degradation processes that potentially lead to the formation of secondary microplastics (MPs), with likely cascade effects upon the whole ecosystem. In this view, this study aims to characterize the plastic beach litter found on the shores of the western basin of Como Lake (Italy) to better understand the origin of MPs in littoral sediments, including the recognition of object typologies and the chemical characterization of polymers using Fourier-transformed infrared analysis (FTIR). The results highlighted that the most abundant polymers on beaches are polypropylene (PP) and polyethylene (PE), representing 73% of the collected polymers. This confirms that floating, low-density polymers are more likely to accumulate on beaches. Moreover, almost 66% of litter is represented by commonly used manufactured items (disposable objects, packaging, and everyday items). This evidence, combined with the analysis of the main environmental features of the sampling sites (the main winds, distance to urban areas, and the presence of tributaries) indicate that abundance of beached litter is mainly linked to beach accessibility and the local winds. These results highlight that multiple factors affect the environmental fate of plastic litter and give insights into the assessment of secondary microplastics in beach sediments.

Assessing sources and fractions of metals associated with environmental plastics: a case study in Lake Como (Italy)

“…77 In addition, the abundance of PE and PP is representative of beached litter, which is generally composed of low-density polymers, which float on water and are transported by surface currents and winds. 55…”

“…77 In addition, the abundance of PE and PP is representative of beached litter, which is generally composed of lowdensity polymers, which oat on water and are transported by surface currents and winds. 55 The FTIR spectra of environmental samples also showed some clear changes in functional groups induced by the environmental ageing of polymers in comparison to the virgin samples. 78 The changes in the indexes for specic aging bands are shown in Fig.…”

“…The main sources of plastic litter in the Bay were observed to be direct littering on the beaches and longitudinal transport of floating litter from the northern part of the lake induced by local winds. 55 We collected plastic litter samples around Villa Geno (45.823° N, 9.076° E, Fig. 1) since this site was observed to be a major hot spot of plastic litter in the area.…”

Physicochemical and biological ageing processes of (micro)plastics in the environment: a multi-tiered study on polyethylene

“…These indexes were calculated to obtain a quantitative reference of surface oxidation of polymers (after UV ageing) as well as the presence of these functional groups in the biofouled fragments. These indexes were also compared with the FT-IR spectra of 4 environmental samples of plastic litter (composed by PE) collected on a lake shore (Bellasi et al 2022).…”

“…Bars are color-indexed by the different physicochemical ageing processes, and error bars indicate the standard deviation (after three replicates). Significantly different values after biofouling (p < 0.05 after t-test) are indicated with an asterisk, while the light green dashed area indicates the average ± standard deviation range of environmental samples (Bellasi et al 2022) the plastic surface. The strong surface degradation is in accordance with the abundant oxidation observed from FT-IR spectra of NaOH-aged specimens (Fig.…”