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.

The widespread occurrence of microplastics (MPs) has resulted in their interaction with biological processes. Thus, there is a great concern about the potential toxicity of MPs on animal and plant cells and on the possibility that MPs reach humans through the food web. In order to shed light on both issues, laboratory assays were performed for evaluating the effects of polyethylene (PE) microparticles on the aquatic plant Spirodela polyrhiza (L.) Schleid. and the gammarid Echinogammarus veneris (Heller, 1865). Moreover, a stock of MP-treated Spirodela plants was used to feed gammarid individuals, and the presence of MP particles in their digestive tracts was analyzed. Results evidenced the lack of toxic effects of MPs on plants, evaluated at growth and physiological level by biometric parameters, pigment content, and photosynthetic performance estimated by chlorophyll fluorescence imaging through the ETPT (EcoTox Photosystem Tool). Only a slight reduction in pigment-related indices in MP-treated plants was observed. A remarkable genotoxic effect was instead highlighted by Comet assay in the hemocytes of gammarid individuals exposed to MPs, with three times more DNA damage (expressed as Tail Moment) in MP-treated individuals compared to control ones. Finally, the gut content of the gammarids fed with MP-treated plants revealed the presence of 7.6 MP particles/individual, highlighting the occurrence of trophic transfer of MPs among freshwater ecosystem organisms. Novel indications about the potential impact of the PE microparticles in the aquatic compartment are provided. Notably, the transfer of MP particles between primary producer and primary consumer organisms of the freshwater trophic chain and the genotoxic effects associated with the ingestion of such particles by gammarids are issues of concern for the aquatic ecosystem and the food web leading to the human diet.

Prompt estimation of phytoplankton biomass is critical in determining the ecological quality of freshwaters. Remote Sensing (RS) may provide new opportunities to integrate with situ traditional monitoring techniques. Nonetheless, wide regional and temporal variability in freshwater optical constituents makes it difficult to design universally applicable RS protocols. Here, we assessed the potential of two neural networks-based models, namely the Case 2 Regional CoastColour (C2RCC) processor and the Mixture Density Network (MDN), applied to MSI Sentinel-2 data for monitoring Chlorophyll (Chl) content in three monomictic volcanic lakes while accounting for the effect of their specific water circulation pattern on the remotely-sensed and in situ data relation. Linear mixed models were used to test the relationship between the remote sensing indices calculated through C2RCC (I_NN) and MDN (I_MDN), and in situ Chl concentration. Both indices proved to explain a large portion of the variability in the field data and exhibited a positive and significant relationship between Chl concentration and satellite data, but only during the mixing phase. The significant effect of the water circulation period can be explained by the low responsiveness of the RS approaches applied here to the low phytoplankton biomass, typical of the stratification phase. Sentinel-2 data proved their valuable potential for the remote sensing of phytoplankton in small inland water bodies, otherwise challenging with previous sensors. However, caution should be taken, since the applicability of such an approach on certain water bodies may depend on hydrological and ecological parameters (e.g., thermal stratification and seasonal nutrient availability) potentially altering RS chlorophyll detection by neural networks-based models, despite their alleged global validity.

Black soldier fly larvae (BSFL) can convert various organic substrates into high added-value biomass. In addition, the residue can be used as a soil conditioner. Several studies have been conducted on a laboratory scale that may not represent what happens on a prototype scale. Using fruit and vegetable waste as a basic substrate, mixing them with agro-industry by-products (called co-substrates), the Hermes project set up a process on medium (2 kg) and large (10 kg) scales with two different feeding regimes (1.25 g/BSFL and 2 g/BSFL). At the mature stage, larval biomass was separated from frass (the by-product of the larval rearing). The production of larval proteins and fats and the use of frass as soil conditioning were evaluated. The lowest feeding regime (1.25 g/BSFL) provided the best waste valorization. The shift towards higher production scales is not completely linear. The addition of co-substrates to fruit and vegetable waste, as they are provided by the large-scale retail trade, can help to standardize a process as part of an insect farm. The frass recovered from the residue of rearing (on the diet or on the agrifood leftovers) was composted and used in field to grow a processing tomato variety. The addition of composted frass assured a slightly lower yield than synthetic fertilizer but there was no statistically significant difference (p > 0.10). This suggests that partial replacement of synthetic fertilizer with composted frass has potential. Overall, the work demonstrated that, using a multidisciplinary approach, the interest and the value in building a supply chain based on bioconversion mediated by Hermetia illucens can be emphasized.

Inland freshwaters are of great importance for human health and activities, but major stressors such as nutrient pollution, deforestation, and urbanization are compromising their status. Water quality degradation and freshwater ecosystem preservation are current issues worldwide requiring frequent and efficient monitoring protocols. The increasing need for large amounts of data to comply with national and international regulations on water quality monitoring highlights traditional procedures limits. Therefore, the purpose of the present study is to investigate the potential of alternative and rapid methods for chlorophyll concentration surveys in freshwaters. The Phyto-PAM (pulse amplitude-modulated) instrument and the Case-2 Regional Coast Colour (C2RCC) satellite image processor were selected to estimate chlorophyll concentration in the surface waters of Lake Albano (Central Italy), selected as a pilot area for the project BLOOWATER (Water JPI 2018 Joint Call Closing the Water Cycle Gap). The correlation tests’ results indicate significant relations with chlorophyll data measured spectrophotometrically, confirming the suitability of both methods for chlorophyll retrieval. However, the relatively low strength of the correlation between remotely sensed and spectrophotometric data (r = 0.57, p < 2.2 × 10⁻¹⁶) was not as satisfactory as with Phyto-PAM values (r = 0.97, p = 1.2 × 10⁻⁴). Even though the techniques in this study proved to be promising in the water body under investigation, their current limitations suggest the need for further calibration and integration with other systems (e.g., unmanned aerial vehicles).

Microplastic (MP) contamination represents a global threat to aquatic ecosystems, yet its biological effects remain poorly understood. This study investigates the short-term impacts of polyethylene (PE) microparticles on two amphipod species: the semi-terrestrial Cryptorchestia garbinii and the aquatic Echinogammarus veneris. Amphipods are exposed to MPs both in water and through dietary intake. After 24 h, C. garbinii ingested an average of 9.6 ± 1.2 particles per individual, while E. veneris ingested 12.5 ± 2.8 particles, confirming an active uptake of microplastics. The mean particle size decreased from ≌50 µm in the food tablets to 18–25 µm in the digestive tract, suggesting fragmentation during digestion and highlighting the ecological role of amphipods in generating smaller, potentially more bioavailable particles. Both species exhibited a marked increase in DNA damage, together with variations in energy-reserve allocation (glucose, glycogen, and lipids) consistent with acute metabolic stress. To our knowledge, this represents the first evidence of genotoxicity ever reported in C. garbinii, expanding current understanding of the biological responses of amphipods to plastic pollution. These findings highlight the vulnerability of detritivore species to MPs exposure and, given their role in nutrient cycling, emphasize the need for further research on the ecological implications of MPs contamination.