## 3 Results and Discussion  
### Overall Litter Density and Sample Composition  
A total of 352 items were collected from the six sampling sites (Table S1). By considering the absolute number of items, the selected beaches showed different amounts of plastic litter, as follows: CE \(>\) VG \(>\) VO \(>\) TP \(>\) FN \(>\) CC. However, the normalization of the results in terms of litter abundance for m\({}^{2}\) demonstrated the actual impact of the plastic litter in the Como area. In fact, the beach showing the highest absolute number of collected items (CE, 120 items) was instead a less-impacted beach in terms of its normalized abundance (0.06 items/m\({}^{2}\)). On the other hand, the most threatened site was represented by VG, with a plastic beach litter density of 0.94 items/m\({}^{2}\) (which instead showed an absolute abundance of 112 plastic objects). Since data on beach plastic litter in freshwater ecosystems are still limited [53], we compared our results with some other findings in both freshwater [54; 55; 56; 57; 58] and marine environments [41; 42; 43] (Table 2). However a direct comparison is still complex, due to the differences in the sampled litter and the selected ecosystems [42; 43; 57]. As for other plastic-related environmental analyses, there is a need for harmonization regarding the sampling and data treatments. Considering these limitations, our data appear to be generally consistent with those reported in other studies [41; 54]. Specifically, the abundance of PL detected in the present study is in line with those observed in Lake Tollense, which among the considered sites, is the closest to our study area. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Location** & **Type of Litter** & **Litter Density** & **References** \\ \hline Como Bay, Italy & PL & 0.06–0.94; mean 0.14 items/m\({}^{2}\) & Present study \\ Black Sea & AL & 0.085–0.508 items/m\({}^{2}\) & [PERSON] et al., 2013 [43] \\ Lake Tollense, Germany & AL & mean 0.2 \(\pm\) 0.1 items/m\({}^{2}\) (72\% & [PERSON] and [PERSON], 2020 [54] \\ Lake Lewisville, Texas & PL & 0.024 items/m\({}^{2}\) & [PERSON], 2019 [55] \\ Lake Michigan & AL & mean 0.0092 items/m\({}^{2}\) & [PERSON] et al., 2015 [56] \\ Central Caribbean Coast, & PL & mean 5.38 items/m\({}^{2}\) & [PERSON] et al., 2020 [42] \\ Columbia & AL & 0.063–1.96 items/m\({}^{2}\) (32.5\% & [PERSON] et al., 2021 [41] \\ Cetta, Spain & AL & plastic litter) & [PERSON] et al., 2021 [57] \\ Puerto Mishualli, Amazonia & PL & mean 0.045 items/m\({}^{2}\) & [PERSON] et al., 2017 [58] \\ Setubal Lake, Argentina & PL & 1.26 items/m\({}^{2}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison between data on plastic litter (PL) and anthropogenic litter (AL) detected in other studies. Considering the polymeric composition of plastics elucidated via FTIR analyses (Figure 3a), the most abundant polymer in the environment was PE (40.34%), followed by PP (32.95%), in accordance with previous findings from marine and freshwater environments [59; 60]. Other common polymers found in quantities <10% were PS (6.25%), PU (4.55%), and PET (4.26%). A small portion of biodegradable polymer, PLA (0.6%), was also detected: this issue was in line with the increasing use of biodegradable plastic materials, but it also raised some concerns regarding the possible persistence of this degradable polymer in natural environments [61]. Moreover, part of the analyzed fragments were identified as being \"vegetal matter\": this is possibly linked to superficial colonization by biological matter (see Section 3.2). Considering instead the categories of the objects collected, a similar composition was observed in all the sampling sites. In accordance with previous findings by [PERSON] et al. [40], most of the plastic litter was related to activities conducted in the proximity of beaches. As a matter of fact, the main categories of beach litter were packaging (39%), everyday objects (15%), and disposable objects (17%).