In aquatic organisms, cadmium exposure occurs from ovum to death and the route of absorption is particularly wide, being represented by skin, gills and gastrointestinal tract, through which contaminated water and/or preys are ingested. It is known that cadmium interferes with the gut; however, less information is available on cadmium effects on an important component of the gut, namely goblet cells, specialized in mucus synthesis. In the present work, we studied the effects of two sublethal cadmium concentrations on the gut mucosa of Danio rerio. Particular attention was paid to changes in the distribution of glycan residues, and in metallothionein expression in intestinal cells. The results show that cadmium interferes with gut mucosa and goblet cells features. The effects are dose- and site-dependent, the anterior gut being more markedly affected than the midgut. Cadmium modifies the presence and/or distribution of glycans in the brush border and cytoplasm of enterocytes and in the goblet cells’ cytoplasm and alters the metallothionein expression and localization. The results suggest a significant interference of cadmium with mucosal efficiency, representing a health risk for the organism in direct contact with contamination and indirectly for the trophic chain.

Worldwide, bacteria are the most ubiquitous microorganisms, and it has been extensively demonstrated that migratory wild birds can increase bacterial global scale dispersion through long-distance migration and dispersal. The microbial community hosted by wild birds can be highly diverse, including pathogenic strains that can contribute to infections and disease spread. This study focused on feather and plumage bacteria within bird microbial communities. Samples were collected during ornithological activities in a bird ringing station. Bacterial identification was carried out via DNA barcoding of the partial 16S rRNA gene. Thirty-seven isolates of bacteria were identified on the chest feathers of 60 migratory birds belonging to three trans-Saharan species: Muscicapa striata, Hippolais icterina, and Sylvia borin. Our results demonstrate the possibility of bacterial transfer, including pathogens, through bird migration between very distant countries. The data from the analysis of plumage bacteria can aid in the explanation of phenomena such as migratory birds’ fitness or the development of secondary sexual traits. Moreover, these results have deep hygienic–sanitary implications, since many bird species have synanthropic behaviors during their migration that increase the probability of disease spread.

The abuse of artificial food dyes and the evidence that they harm human health recently prompted a significant effort to introduce vegan substitutes prepared from fruits and vegetables. Not much information, however, has been collected on their possible effects on aquatic and terrestrial ecosystems once released as waste in surface waters. For this purpose, we analyzed the effects of a vegan red (VEG) preparation (concentration 1.2 g/L) on three rapidly proliferating models for terrestrial and aquatic ecosystem contamination. In particular, in vitro cells cultures (exposure for 24 h), Artemia salina nauplii and Cucumis sativus seedlings (exposure 5 days). A comparison was made with the effects exerted by the two dyes that vegan red is intended to replace: an animal dye, cochineal E120 and an artificial dye E124. The analyses of conventional endpoints, indicative of cell proliferation, differentiation, and growth rate, demonstrate that the three dyes affect development and that the vegan substitute is as unsafe as the E124 and E120. Vegan red in fact impairs cell growth in in vitro cells, delays naupliar hatching and early growth in Artemia, and reduces shoot/root biomass in Cucumis. Marked hyperplasia and hypertrophy of mesophyll are also observed in Cucumis leaves. Substitution in food and beverages, therefore, should be carefully reconsidered to avoid unnecessary environmental contamination.

In recent years, the introduction of alien and invasive marine species in the Mediterranean Sea has rapidly increased. Laonome triangularis is a sabellid worm, native to the Australian coasts. Its first record in the Mediterranean Sea dates back to 2009 and, in this area, it is currently labeled as an allochthonous species. In the present work, we report the fìrst record of this polycheate in Italian waters and we provide some diagnostic features that are useful to identify the species.

Urban rivers represent a highly vulnerable environment due to the intense anthropogenic pressures and the restricted self‐depuration capacity. The current monitoring programs often lack to provide a full knowledge of all contaminant sources and processes governing their behaviour due to the complexity and variability of the conditions in urban water bodies and the increasing occurrence of new pollutants such as the Contaminants of Emerging concern (CECs). This called for an increasing regulatory attention and the need to carry out the revision of the Water Framework Directive (WFD), as it is currently ongoing. This study proposes an integrated new approach for urban water quality assessment, which combines traditional parameters, emerging contaminants, (i.e. CECs and Microplastics-MPs), isotopic tracing and modelling, with the aim of improving source discrimination and advancing the understanding of contaminant dynamics in heavily modified urban rivers. The new approach was tested on a selected stretch of the Tiber river, within the city of Rome. Data of pollutant concentrations, measured along the water body close by the point source releases, were combined with the hydraulic information through a mass‐balance approach with the aim to quantify contributions of different processes. The stable isotope ratios were evaluated as tracers for identifying contaminant origins and potential transformation processes, representing an innovative application in the context of urban river monitoring. Additionally, the Qual2K model was employed to simulate water‐quality dynamics under varying hydrological and meteorological conditions, focusing on the behaviour of CECs.

Cadmium is a common contaminant of both saline and freshwater environments. It has no biological function but readily penetrates tissues, causing significant oxidative stress and consequent damage throughout the organism. In this work, we examined the effects of this metal on the nauplii of Artemia salina, a model for testing toxicity in larval zooplanktonic species, and to evaluate the impact of contaminants on natural populations. An environmentally realistic concentration (15 µg/L) and two higher concentrations (150 and 1500 µg/L) were used. The presence of metals in culture media and nauplii was verified by atomic absorption spectroscopy, while oxidative stress levels were assessed by measuring hydroperoxides, carbonyl groups, ROS, and total antioxidant capacity. Mortality and growth rates were the conventional toxicity endpoints analysed. In parallel, morphological alterations were assessed in toto and in section. Attention was directed to the gut, the primary site of metal uptake and reabsorption, and to effects on protein patterns. The results demonstrated significant dose-independent Cd uptake by the nauplii and dose-dependent oxidative stress. Consequent alterations in brush border organisation and yolk and lipid resorption were assessed. Modest teratogenic effects were detected in naupliar eye pigmentation and paired-eye organisation. Oxidative stress and the marked changes in protein pattern justify the alterations observed, while the upregulation of the hsp26 and hsp60 genes indicates naupliar attempts to mitigate damage. In conclusion, this study confirms the effects of Cd toxicity on the development of Artemia salina nauplii and demonstrates interference with reserve resorption. This evidence indicates that this heavy metal can have a profound impact on zooplanktonic communities, which are essential to the stability of the entire aquatic food web.