Accumulation of As, Cd, Pb, and Zn in sediment, chironomids and fish from a high-mountain lake: First insights from the Carnic Alps

Though mountain lakes are generally much less influenced by human activities than other habitats, anthropogenic threats can still alter their natural condition. Amajor source of global environmental pollution inmountain ecosystems is trace element contamination. For this studywe investigated for the first time the accumulation of As, Cd, Pb, and Zn in sediment, Diptera Chironomidae (prey), and bullhead Cottus gobio (predator) in a typical high-mountain lake (Dimon Lake) in the Carnic Alps. Significant differences in trace element levels were observed between sediment, Diptera Chironomidae, and C. gobio liver and muscle samples (Kruskal-Wallis test; p b .03 for all elements). As and Pb levels were highest in sediment, Cd and Zn levels were highest in Diptera Chironomidae, and the lowest values for all elementswere measured in C. gobio muscle and liver. Bioaccumulation factor values weremuch higher in Diptera Chironomidae than fish muscle and liver, with the highest values recorded for Cd (5.16) and Zn (4.37). Trophic transfer factor valueswere very lowfor all elements in fish muscle and liver, suggesting a biodilution effect along the food chain. Further studies are needed to expand on these first findings that provide useful insights to inform environmental monitoring and policy in remote high-mountain lakes

Lethal and Sublethal Responses of Hydropsyche pellucidula (Insecta, Trichoptera) to Commercial Polypropylene Microplastics after Different Preconditioning Treatments

Microplastics (MPs) pose biological and chemical hazards in aquatic and terrestrial food webs across the globe. Research on microplastic contamination has long focused on marine ecosystems, whereas the toxicological impact on freshwater organisms is still little explored. In this study, the lethal and sublethal response of the freshwater macroinvertebrate Hydropsyche pellucidula exposed to polypropylene MPs after different pre-conditioning treatments was assessed. Field samples were collected in a riverine system (Vipacco river; northeast Italy) to assess the characteristics of the MPs in the aquatic environment Both water and sediment were contaminated by MPs (3.73 ± 2.11 items m−3 per min and 3.33 ± 4.16 items dm−3, respectively). The chemical MPs composition included polystyrene, polyethylene terephthalate, polyurethane, polyamide, polypropylene, and polyethylene. Polypropylene (PP), although not the most abundant polymer recorded in the study area, was preferred over the other types according to its abundance in freshwater and H. pellucidula feeding behavior. A housing test was performed to recreate the natural conditions of larvae sampled for a reliable response to the ecotoxicological tests. The microplastics underwent either preconditioning with Vipacco River water (PP-river) and surfactant Triton X-100 (PP-sf) or no pre-treatment (PP). Submersion of microplastics in 10 µg L−1 of surfactant solution for 24 h was sufficient to induce consistent spectral changes and modify the chemical profile of the plastic surface. Mortality rate differed according to treatment: PP and PP-river > positive control > PP-sf > negative control. Integrated biomarker response (IBRv2) and analysis of oxidative stress biomarker levels showed a greater response of superoxide dismutase and lipid peroxidation (malondialdehyde) in larvae treated with PP conditioned in surfactant. Our findings enhance knowledge on the toxicity of PP and conditioning phases on H. pellucidula larvae.This research received no external funding.Peer reviewe

Changes in Serum Blood Parameters in Farmed Rainbow Trout (Oncorhynchus mykiss) Fed with Diets Supplemented with Waste Derived from Supercritical Fluid Extraction of Sweet Basil (Ocimum basilicum)

The antimicrobial and immunostimulant proprieties of aromatic plant extracts have been widely described, but their effects on serum blood biochemistry in fish have not. For this study, we assessed the changes in serum blood biochemical parameters in rainbow trout fed with a fish diet supplemented with a basil supercritical extract (F1-BEO). Our hypothesis was that treatment and time would be associated with changes in 10 serum blood biochemical parameters. F1-BEO was added to a commercial feed (0.5, 1, 2, 3% w/w). The fish were fed for 30 days, and the blood samples were collected at 2 time points (15 and 30 days). A two-way ANOVA showed a significant effect of treatment, time, and interaction treatment × time on creatinine, urea, total protein, albumin, magnesium, and phosphorus (p < 0.05), a significant effect of both time and interaction treatment × time on cholesterol (CHOL), glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) levels, and a significant effect of time on triglycerides (p < 0.05). While changes in several of the parameters were observed, the levels remained within the normal range for rainbow trout. Notably, after 30 days there was a significant decrease in CHOL in fish treated with 0.5% and 1% w/w F1-BEO (p < 0.05). The statistically non-significant increase in GOT and GPT in the fish fed with F1-BEO up to 3% w/w indicated a positive effect of basil on liver health. Our findings suggest a potential use for basil extracts (for example., F1-BEO) in fish feed to reduce antibiotic use and improve fish welfare.This research was funded by Italian Ministry of Health, Ricerca Finalizzata, grant number GR-2013-02355796.Peer reviewe

Modulation of Antioxidant Defense in Farmed Rainbow Trout (Oncorhynchus mykiss) Fed with a Diet Supplemented by the Waste Derived from the Supercritical Fluid Extraction of Basil (Ocimum basilicum)

Phytotherapy is based on the use of plants to prevent or treat human and animal diseases. Recently, the use of essential oils and polyphenol-enriched extracts is also rapidly increasing in the aquaculture sector as a means of greater industrial and environmental sustainability. Previous studies assessed the antibacterial and antiparasitic effects of these bioactive compounds on fish. However, studies on the modulation of oxidative stress biomarkers are still scant to date. Thus, in this study, the modulation of antioxidant defense against oxidative stress exerted by fish diets supplemented with a basil supercritical extract (F1-BEO) was assessed in rainbow trout Oncorhynchus mykiss. The F1-BEO extracted with supercritical fluid extraction was added to the commercial feed flour (0.5, 1, 2, 3% w/w) and mixed with fish oil to obtain a suitable compound for pellet preparation. Fish were fed for 30 days. The levels of stress biomarkers such as superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glyoxalase I, glyoxalase II, lactate dehydrogenase, glutathione and malondialdehyde showed a boost in the antioxidant pathway in fish fed with a 0.5% F1-BEO-supplemented diet. Higher F1-BEO supplementation led to a failure of activity of several enzymes and the depletion of glutathione levels. Malondialdehyde concentration suggests a sufficient oxidative stress defense against lipid peroxidation in all experimental groups, except for a 3% F1-BEO-supplemented diet (liver 168.87 ± 38.79 nmol/mg prot; kidney 146.86 ± 23.28 nmol/mg prot), compared to control (liver 127.76 ± 18.15 nmol/mg prot; kidney 98.68 ± 15.65 nmol/mg prot). Our results suggest supplementing F1-BEO in fish diets up to 0.5% to avoid potential oxidative pressure in farmed trout.This research was funded by Italian Ministry of Health, Ricerca Finalizzata, grant number GR-2013-02355796.Peer reviewe

Food selection by Plumatella geimermassardi Wood and Okamura, 2004 (Phylactolaemata, Bryozoa)

Bryozoans are sessile filter feeding organisms able to play an important role in the cycling of organic matter in freshwater ecosystems. However, the quality and quantity of food particles ingested by bryozoans are still not well-known. Therefore, an experimental design was performed in order to investigate the clearance rate (CR), food selection and efficiency of assimilation by the freshwater bryozoan species Plumatella geimermassardi. P. geimermassardi was collected from the Colfiorito Marsh (Umbrian Natural Park, Italy), during summer. A higher grazing rate of suspended and dissolved solids was evidenced in the colonies collected in June, July, than in August. Food selection and assimilation of phytoplankton were determined. The algal species ingested as diet food item and those excreted with the faecal pellets were taxonomically identified. The results provide new information on CR and food selection by P. geimermassardi and enhance knowledge on its biology. Insights on feeding preferences by bryozoan species can provide valid information about their feasible distribution and abundance