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Rivers are undoubtedly the main pathway of waste dispersed in the environment that from land reaches oceans and seas increasing the amount of marine litter. Major cities are a great source of riverine litter as large urbanization can originate pressure on the integrated waste management resulting in litter entering the rivers. Within this study, we aim to investigate the dynamic of floating riverine macrolitter (items2.5 cm) in the city of Rome before it reaches the sea by assessing the composition, amount, and seasonal trends of litter transported from the urban centre to the main river mouth of Tiber River. Visual surveys for a whole year (March 2021-February 2022) were conducted from two bridges, Scienza Bridge (in the city) and Scafa Bridge (at the main river mouth) and followed JRC/RIMMEL protocol for riverine litter monitoring. Overall, similar litter composition was observed from the city centre to the mouth with a prevalence of plastic material, mainly related to fragmentation process (i.e. plastic pieces) and single use items, mainly in food and beverage sectors. An extrapolated annual loading of 4 × 10

This study analyzes the occurrence and distribution of plastic litter and the entrapment of plastic by wrack beached on a natural reserve. Large microplastics (2.5 - 5 mm) were the most abundant plastic size category detected. The main color and shape were white and fragment, respectively. The plastics entrapped by egagropiles were mainly transparent fibers. We analyzed the correlation between the weights of plastic litter and vegetal wrack in two transects, selected for their different environmental characteristics. The transect closer to a breakwater showed a significant positive correlation between the weights of plastics and wrack, while the other transect suggested a casual pattern of plastic deposition on the beach. Further research is suggested to focus on the role of breakwaters in altering marine currents and enhancing plastic beaching.

Plastics are to date considered one of the main detrimental drivers for the health of aquatic ecosystems, both in marine and inland waters. Regarding the latter habitat, it seems surprising how the plastic effects on benthic invertebrates are neglected since macroinvertebrates have a long tradition in the water quality assessment activities. In this context, we propose timely indoor observations on the exposure of caddisfly Odontocerum albicorne and mayfly Ephemera danica to various microplastic polymers (ABS, PET, PP, PS, PVDF). Three different experimental designs were performed on caddisflies and mayflies by exposing their larvae to natural and microplastic substrates. Our findings highlighted how microplastics affected both caddisflies in rebuilding its own case (after having removed the natural one) and mayflies burrowing. Particularly, all caddisflies rebuilt cases using the microplastic polymers provided instead of natural items only. Moreover, we provide the first evidence that mayflies burrow mainly in microplastic substrates rather than in natural ones. Our research highlights that macroinvertebrate larvae would use naturally occurring microplastics and this could be of particular concern in freshwaters with high contamination by plastics. Indeed, larvae appear to not necessarily perceive microplastics as a direct stressor. Further studies ought to be conducted to understand the chronic perturbation on larvae fitness and for example, on drift behaviour. Also, further investigations are needed to understand the potentialities of using plastics by benthic macroinvertebrates.

The release of plastics in freshwater is an increasing concern for ecosystem safety worldwide. There is a large knowledge gap on plastic pollution in Mediterranean freshwater, especially regarding surveys along entire river courses, partly due to the absence of guidelines for standardized monitoring of plastics. The present study analyzes the plastic distribution from source to mouth, also according to the River Continuum Concept, of the environmental matrices (water and sediments) and biota (caddisfly cases) of the Mediterranean River Mignone and their cause-effect relationship. The results of the water quality indices (Extended Biotic Index and Fluvial Functionality Index) were compared with the plastic concentrations observed in the water and sediments to explore what relationship there might be and to understand if the indices could be a proxy of the plastic pollution. Our results showed a significant prevalence of blue fibers, the concentration of which in water and sediment is positively associated. Plastic concentration at each site was not accurately detected by the water quality indices. These results may suggest that the factors considered by water quality indices are not able to detect the contamination of plastic pollution. It is mandatory to identify new tools for assessing the plastic impacts on river ecosystems.

Freshwaters are vulnerable ecosystems owing to several anthropogenic impacts, including chemical pollution. Among existing model organisms, the cnidarian Hydra vulgaris is widely used for toxicological tests, with the aim of detecting either toxicity or teratogenicity of different dissolved chemicals. Given the widespread range of applications and developed assays, the aim of this review was to show and discuss the actual use of this model for ecotoxicological assessments in freshwaters as an ‘early warning system’. To achieve this goal, a thorough review was conducted by consulting several search engines for peer-reviewed international articles. Among all resulting articles from literature search, those focusing on H. vulgaris assay applied to environmental pollution were first selected (n=19). Then, only articles that specifically tested freshwater samples collected directly in the field were considered (n=4). The literature search highlighted that Hydra assays are suitable monitoring tools for freshwater ecotoxicity assessment. In addition, H. vulgaris allows testing diverse biomarkers (e.g. molecular, histological, morphological and behavioural) and exploring innovative research fields. So as to be able to assess the impact of emerging contaminants on both habitat and human health, the Hydra assays are demonstrating that they have an increasing potential that must be exploited.