Insect-based aquafeeds modulate the fatty acid profile of zebrafish: a comparison on the different life stages

Insects are considered as an alternative and sustainable ingredient for feed production. In this study, Hermetia illucens (Hi) prepupae (fed on coffee roasted by-product added with 10% Schyzochytrium sp., a marine protist rich in polyunsaturated fatty acids) was processed into meal and included at graded levels in five experimental diets to replace dietary fish meal (0, 25, 50, 75, 100%) offered to zebrafish (Danio rerio) as experimental model. The fatty acids (FAs) profile of fish larvae (20 days), juveniles (2 months, deprived of the viscera) and adults (6 months, male and female, deprived of the viscera) specimens was investigated to evaluate the impact of dietary FM replacement with full-fat Hi prepupae meal. For the first time, the quantification of FAs in Danio rerio, performed by gas chromatography-mass spectrometry, was computed in absolute terms (mg 100g-1 dw), identifying the real variation in the content of any single FA. In fish, quantified total FAs in larvae, juvenile, adult male and adult female were 134±2, 235±8, 266±3 and 266±8 mg g-1 dw, respectively. With respect to zebrafish fed the control diet, specimens fed diet with increasing level of Hi prepupae meal showed significantly higher content of saturated and omega6 FAs, and significantly lower content of poly-unsaturated and omega3 FAs, reflecting partially the FAs composition of the administered diets. At the same time, the docosahexaenoic/eicosapentaenoic acid ratio increased significantly. Moreover, adult female showed a higher content of PUFA with respect to adult male, which could be justified by the needs of physiological reproductive processes. The principal component analysis demonstrated that the FAs composition in Danio rerio depends on both the life stage and the diet

The Interreg Project AdSWiM: Managed Use of Treated Wastewater for the Quality of the Adriatic Sea

The Italy-Croatia Cross Border Cooperation (CBC) Programme is the financial instrument supporting the cooperation between the two European Member States overlooking the Adriatic Sea. The first call for proposals was launched in 2017, identifying four priority axes of intervention. Subsequently, in 2019, the kick-off of the AdSWiM project “Managed use of treated urban wastewater for the quality of the Adriatic Sea” took place in Udine (IT). Adriatic marine waters are generally classified as good to excellent based on the Bathing Water Directive (2006/7/EC). Nevertheless, issues of low productivity or the lack of nutrients have been often suggested, especially on the Italian side. The project addresses the question of whether wastewater treatment plants (WWTPs) discharging to the sea, after applying appropriate pollution control and management technologies, can modulate the nutrient content of their effluents to support localized depleted areas. This idea is borrowed from one of the motivations that support the reuse of treated wastewater for irrigation, thus leading to the return of nutrients (nitrogen, phosphorus, potassium, etc.) to natural biogeochemical cycles. However, the hypothesis of modulating the nutrient composition of wastewater opens up to several critical aspects, including legislative and technological ones. Being aware of the delicate environmental implications, we have undertaken the project involving WWTPs, research centers, municipalities, and legal experts with the aim of investigating in detail the problems related to wastewater reuse, especially with regard to the content of nutrients. Our experimental approach aimed to evaluate appropriate and possibly new treatment technologies to reduce the microbial load and to implement chemical and microbiological tests on the treated wastewater. Results have shown that it can be tricky to draw decisive conclusions because (i) the wastewater management systems differ between the two sides of the Adriatic sea due to the different levels of technological development of WWTPs; (ii) the Italian and Croatian coasts deeply differ in geographic characteristics (i.e., topography, orography, current circuits, presence of rivers) and anthropogenic pressure (i.e., exploitation levels, population density); (iii) the new treatment technologies to lower bacterial contamination need further efforts to raise their technological level of readiness (TRL) and make them implementable in the existing WWTPs. However, in terms of chemical control methodologies, the proposed sensors and biosensors gave positive results, managing to decrease the detection limits for the measured parameters, and the tested technologies for microbiological monitoring were also effective. In particular, the latter was carried out by using recent molecular biology techniques, capable of resolving the microbiota in treated wastewater, which emerged to be strictly related to the features of the WWTPs

Mercury in honey from the Marche region (central Italy). Risk assessment from human consumption and its use as bioindicator of environmental pollution

Honey is a natural product made by honeybees (Apis mellifera) from nectar or honeydew. It is a very popular and appreciated product all over the world as it represents a rapidly available energy source and exerts several beneficial properties for humans. However, it has been demonstrated that honey can be contaminated by potentially toxic elements (PTEs) of natural or anthropogenic origin. Among them, mercury (Hg) represents one of the most dangerous for its toxicity and its capacity to biomagnify along the trophic web. In the present study, 100 honey samples from the Marche Region (Central Italy) produced in the year 2021, were analyzed by thermal decomposition amalgamation atomic absorption spectrometry to determine the Hg content. The overall mean concentration was 0.2 ± 0.2 μg kg-1. The results showed that no statistically significant differences were found in Hg content among honey from different pollen origin, but honeydew had a significantly higher Hg content with respect to all other honey samples (0.6 ± 0.3 μg kg-1). The Hg content in honey depends mainly on local pollution, while geographical origin did not play a key role. Furthermore, considering the regulatory limits and provisional tolerable weekly intake (PTWIs) identified by FAO/WHO, the Hg Hazard Quotient (HQ) measurement revealed that this product is safe for human consumption

The prokaryotic community of Chondrosia reniformis Nardo, 1847: from diversity to mercury detection

Microbial communities inhabiting sponges are known to take part in many metabolic pathways, including nutrient cycles, and possibly also in the bioaccumulation of trace elements (TEs). Here, we used high-throughput, Illumina sequencing of 16S rRNA genes to characterize the prokaryotic communities present in the cortex and choanosome, respectively the external and internal body region of Chondrosia reniformis, and in the surrounding seawater. Furthermore, we estimated the total mercury content (THg) in these body regions of the sponge and in the corresponding microbial cell pellets. Fifteen prokaryotic phyla were detected in association with C. reniformis, 13 belonging to the domain Bacteria and two to the Archaea. No significant differences between the prokaryotic community composition of the two regions were found. Three lineages of ammonium-oxidizing organisms (Cenarchaeum symbiosum, Nitrosopumilus maritimus, and Nitrosococcus sp.) co-dominated the prokaryotic community, suggesting ammonium oxidation/nitrification as a key metabolic pathway within the microbiome of C. reniformis. In the sponge fractions, higher THg levels were found in the choanosome compared to the cortex. In contrast, comparable THg levels found in the microbial pellets obtained from both regions were significantly lower than those observed in the corresponding sponge fractions. Our work provides new insights into the prokaryotic communities and TEs distribution in different body parts of a model organism relevant for marine conservation and biotechnology. In this sense, this study paves the way for scientists to deepen the possible application of sponges not only as bioindicators, but also as bioremediation tools of metal polluted environments.info:eu-repo/semantics/publishedVersio

Dissolved Potentially Toxic Elements (PTEs) in Relation to Depuration Plant Outflows in Adriatic Coastal Waters: A Two Year Monitoring Survey

The Adriatic Sea is vulnerable to pollution due to its low bathymetry, intense industrial activity, and tourism. In this context, a good depuration plant activity could play a key role for the maintenance of a good environmental quality. In the framework of the AdSWiM project, “Managed use of treated urban wastewater for the quality of the Adriatic Sea”, a study on dissolved potentially toxic element (PTE) levels was carried out to assess the impact of treated urban wastewaters on the quality of the bathing waters in the Adriatic Sea during the 2019 and 2020 summer period. In the present study, three areas along the Italian–Croatian coastline (Gulf of Trieste, Zadar, and Split) were identified for the monitoring of five depuration plant (DP) outflows. Water samples were collected after the treatment inside the DPs, and coastal seawater was sampled in the proximity of the discharging pipelines. Dissolved Hg, Cd, and As levels were determined with an atomic fluorescence spectrometer. Results did not show statistically significant differences between treated wastewater and seawater samples (Hg 10 ± 6 and 10 ± 4, Cd 14 ± 6 and 21 ± 8, As 610 ± 176 and 687 ± 140 ng L−1, respectively), while the geographical area and the seasonality affected the PTE concentration. Furthermore, the levels detected were lower than the European and national limits, indicating a good environmental status of the northern Adriatic Sea waters. The determination of further parameters (nutrients, microbiological indicators) must be investigated to identify possible synergistic effects. However, our results demonstrate the efficiency of DPs investigated, underlining the importance of the wastewater treatment for the protection of the Adriatic Sea

Seasonal Evolution of Size-Segregated Particulate Mercury in the Atmospheric Aerosol over Terra Nova Bay, Antarctica

Size-fractionated particulate mercury (PHg) measurements were performed from November 2017 to January 2018 at Terra Nova Bay (Antarctica) for the first time. Samples were collected every 10 days by a six-stage high-volume cascade impactor with size classes between 10 µm and 0.49 µm. Total PHg concentrations were maxima (87 ± 8 pg m−3) in November, then decreased to values ~40% lower and remained almost constant until the end of the sampling period (~30 pg m−3). The trimodal aerosol mass distribution reveals that from 30% to 90% of the total PHg came in the size > 1.0 µm. Hg in the two coarse fractions was probably produced by the adsorption of oxidized Hg species transported by air masses from the Antarctic plateau or produced locally by sea ice edges. PHg in accumulation mode seemed to be related to gas–particle partitioning with sea salt aerosol. Finally, average dry deposition fluxes of PHg were calculated to be 0.36 ± 0.21 ng m−2 d−1 in the accumulation mode, 47 ± 44 ng m−2 d−1 in the first coarse mode, and 37 ± 31 ng m−2 d−1 in the second coarse mode. The present work contributed to the comprehension of the Hg biogeochemical cycle, but further research studies are needed