1,721,068 research outputs found
Biofuel Production from the Orbetello Lagoon Macrophytes: Efficiency of Lipid Extraction Using Accelerate Solvent Extraction Technique
No full textIn this paper, the efficiency of lipid extraction from macrophytes (Chaetomorpha linum, Ulva laetevirens, Valonia aegagrophyla, Gracilariopsis longissima, Ruppia cirrhosa) for the biodiesel production is evaluated using four different methods based on the Accelerated Solvent Extraction technique. Both wet and dried tissues are extracted and effects induced on lipid recovery by the pressure and the solvent mixture selection are evaluated. Results evidenced that better extraction performance is obtained using a polar/hydrophobic solvent mixture (1:1 v/v). Accelerate Solvent Extraction technique significantly improves the total amount of lipid extracted from macrophytes tissues even if average values are about 2% of the dry weight. Observed efficiencies are far from the productive standards required by the industrial proc- ess; nevertheless, lipid extraction from macrophytes could represent an interesting step of a much more complex bio- mass recycling process which could include, besides biodiesel, also, the production of other commercial materials as well as pigments and biosorbents
Responses of Aquatic Vegetation to Pollution: Preliminary Results on Ecotoxicological Effects and Bioenrichment Factors
No full textThis study evaluates, on a preliminary basis, the principal morpho-physiological effects induced by pollution stress in four aquatic vegetation species of great ecological relevance in transitional water ecosystems. Three macroalgae (Chaetomorpha linum, Valonia aegagrophyla, Graciliariopsis longissima) and one phanerogams species (Ruppia cirrhosa) were exposed to different doses of trace elements (Cu, Hg, Zn) and surfactants (dodecylbenzenesulfonic acid sodium salt) in laboratory controlled microcosm conditions and morpho-physiological responses (photosynthetic complex alteration, percentage of died cells, morphological changes) were measured before and after 7 and 14 days of exposure. Levels of pollutants in tissues and BioConcentration Factors (BCF) for each species were calculated after 14 days of exposure. Results suggest that photosynthetic complex alteration can be a useful tool to evaluate early and sub-lethal significant changes due to exposure to pollution stress in all of the considered species. A clear species-specificity was observed concerning trace element levels in tissues after 14 days of exposure, while dose-dependent behavior was observed for BCFs
Plastic litter transfer from sediments towards marine trophic webs: A case study on holothurians
No full textThis study estimates for the very first time plastic litter levels in sea cucumbers (Echinodermata, Holothuroidea) sampled in situ and their intakes from sediments in three different rocky bottom habitats (slides, cliff, banks) settled in Salina Island (Aeolian Archipelago). Macroplastic were never recorded while meso- and microplastics were identified in all sediment (81–438 items/kg d.w.) and animal samples (1.8–22 items/ind.). Plastic intakes by sea cucumbers resulted frequently associated to the size range included within 100–2000 μm. Over than 70% of ingested plastic litter is represented by the size fraction >500 μm. Sediment/animals ratios % are included 2.7 ± 2.0% in studied habitats with a selective intake of fragments occurring in slides. Furthermore, results support the occurrence of selective ingestion of plastic litter by holothurians in natural environments underlining the role of these species in microplastic transfer from abiotic towards biotic compartments of the marine trophic web
Ecotoxicity of marine sediments: Sampling and laboratory artifacts and their impacts on risk classification
Full text linkAssessing the ecotoxicological risk of marine sediments is now a critical factor in deciding how to treat dredged material in harbor and coastal areas. Although ecotoxicological analyses are routinely required by some regu-latory agencies in Europe, laboratory skills necessary to perform them are often underestimated. According to the Italian Ministerial decree No. 173/2016, ecotoxicological tests are performed on the solid phase and elutriates, and the classification of sediment quality is defined using the "Weight of Evidence" (WOE) approach. However, the decree does not provide adequate information regarding the preparation techniques and laboratory skills. As result, a wide variability among laboratories occurs. An error in the classification of ecotoxicological risk has a negative impact on the whole environmental quality and/or the economy and management of the interested area. Thus, the main aim of this study was to determine if such variability can affect the ecotoxicological out-comes of tested species and WOE associated classification, producing different options for the management of dredged sediments. Four different sediment types were selected to assess the ecotoxicological responses and their changes as a function of variability of the following factors: a) the storage time laps (STL) for both the solid phase and the elutriates; b) the methods used to prepare the elutriates (centrifugation vs. filtration), and the conser-vation method used for the elutriates (freshly prepared vs. freezing). Results suggest a wide variability of eco-toxicological responses among the four sediment samples here considered, differentiated according to chemical pollution, grain-size texture, and macronutrient contents. The storage time laps significantly affect the physi-cochemical parameters and the ecotoxicity of both the solid phase test and elutriates. For the elutriates prepa-ration, centrifugation is preferred to filtration to preserve a better representation of sediment heterogeneity. Freezing of elutriates does not seem to show any significant effects on the toxicity. Findings allow to define a weighted schedule of the storage time of sediments and elutriates useful for laboratories to scale analytical priority and strategies related to different sediment types
Single-Use Plastic in the Lebanese Restaurants: Awareness and Environmental Impacts during the Economic Crisis: A Case Study of Touristic Regions
No full textIn recent years, single-use plastics have attracted increasing interest, mainly because they are suspected of accumulating in the environment and thus also in biota. Although they have been studied by researchers to investigate their impact on health, the economy, society and the environment, plastics have become the most important material used in our daily lives. They are present in the catering industry due to their durability, low cost and ease of use in construction, replacing many other materials. However, the same properties that make plastics so advantageous also make them undesirable for the environment, especially as most plastic are designed to be thrown away immediately after a single use. The aim of this study is to assess the awareness and environmental impact of single-use plastic in Lebanese restaurants in order to investigate the lifespan of plastic and the potential to replace it with sustainable and biodegradable products. The results show that despite their responses indicating a strong environmental awareness, managers are still in favor of using single-use plastic
Levels of Mercury and Polychlorobiphenyls in Bluefin Tuna from the Western Mediterranean Sea: A Food Safety Issue?
Full text linkIn this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 blue- fin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) and Villa Putzu (South East Sardinia, Italy) in order to assess the current levels of these two contaminants in fish muscle and the consequent risk to humans consuming said fish. Values of polychlorobiphenyls in bluefin tuna muscle vary be- tween 0.155 and 1.403 mg/kg f.w.; the average of PCBs in tuna muscle is 0.732 mg/kg f.w. With regard to PCBs the presence of more elevated concentrations is confirmed in larger fish. The results regarding mercury in mus- cle show an average of 0.660 mg/kg f.w. and mercury values vary between 0.140 f.w. and 2.211 mg/kg f.w.; for mercury as well, the highest concentrations were found in the largest bluefin tuna. Six samples, 26% of total, contained more than 1 mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for this species. Mercury, in particular methylmercury, poses a risk to public health, therefore, taking into account the important nutritional contribution that tuna fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children strictly limit their consumption of tuna from this area of the Mediterranean
Ecotoxicological assessment, in freshwater environment, of wastewater sludge coupled and uncoupled with micro‐polyvinyl chloride on algae and water fleas
No full textIn the frame of bioeconomy and circular economy, wastewater sludge (WS) could be a good candidate for its use in agriculture as fertilizer, due to its high content of organic matter, N and P, but on the other hand, it is full of toxicants such as heavy metal, microplastics, detergent, antibiotics, and so on that can reach groundwater and water bodies in leachate form. In this study, we have investigated different sludge concentrations in the eluate form, combined and not with PVC on two different freshwater organisms Selenastrum capricornutum and Daphnia magna, using ecotoxicity tests. At the endpoint, we have evaluated inhibition growth rate, oxidative stress, and pigments production for S. capricornutum, while in case of D. magna, we have assessed organism immobilization and development. From our results, it emerged that at the higher WS concentration, there was not inhibition growth rate, while at oxidative stress, it was higher in algae treated with WS and PVC. Higher Chl-a production was shown for algae treated with 0.3 g/L of sludge coupled with PVC, where higher phaeopigments production were recorded for algae treated with 0.3 g/L of WS. D. magna has shown an opposite trend when compared with algae, where at the highest WS concentrations supplied was corresponding to an increased mortality explaned as the highest immobility percentage. PRACTITIONER POINTS: Wastewater sludge is used in agriculture as fertilizer. PVC microplastic presence and associate ecotoxicity was tested. PVC presence increased oxidative stress in S. capricornutum. D. magna was significantly affected by sludge concentrations supplied
Taking the sparkle off the sparkling time
No full textThe awareness of impact of microplastics has led stakeholders to define strategies for the reduction of plastic
emission and for their removal from aquatic environments. Glitter includes a wide range of shapes, chemical
types of plastics covered by a metallic layer and color addition that confer them the typical ‘sparkling’ aspect.
Here we focus on critical aspects that make glitter a product with a potential of significant environmental impact suggesting the need to take effective measures to limit emissions. Glitter is used here as a paradigm for all emergent plastic pollutants which calls for a deeper rethinking of our concept of sustainability. We are only at the
beginning of the studies on glitter in the aquatic environment but on the basis of their potential impacts now is the time to take decisions taking the sparkle off the sparkling time
Production of methyl mercury by sulphate-reducing bacteria in sediments from the Orbetello lagoon in presence of high macroalgal loads
Full text linkMethylmercury is a potent neurotoxin affecting shallow-water ecosystems. Mercury polluted sediment samples were collected at six different sites in the Orbetello Lagoon (central Italy) characterized by high levels of silt, iron, manganese hydroxides, and organic matter originated the latter originated from the decomposition of macroalgae. Porous water pointed out the presence of sulphates, methylmercury, and sulphides. Slurries arranged in anaerobic conditions from sediment aliquots from the six sites, with the addition of ionic mercury, highlighted the production of methylmercury. Sulphate reducing bacteria (SRB) were quantified in lagoon sediments; furthermore, sediments cultured under anaerobic conditions showed SRBs active in mercury methylation. Anaerobic cultures of SRB, amended with ionic mercury, produced methylmercury during the growth of bacterial cells. The percentage of aerobic mercury resistant bacteria was pointed out at each sampling site, evidencing the presence of bioavailable mercury. Several aerobic mercury resistant bacteria were isolated and their level of resistance to inorganic and organic forms of mercury was evaluated. These isolates may be potentially used for eventual bioremediation processes. Mercury methylation by SRB in the Orbetello Lagoon sediments was described for the first time, focusing the attention on the need for possible bioremediation processes by using autochthonous mercury resistant bacteria. Moreover, the influence of algal biomass on mercury methylation was highlighted for the first time in this lagoon ecosystem. The importance of removing algal biomass, as it represents a source of organic matter favouring the process of mercury methylation, was strongly pointed out in this stud
Journey into the Local Market in Search of “Glitter” Microparticles: Mini Product Investigation and Relative Chemical-Physical Characterization
Full text linkThere is one type of primary microplastic, glitter, which has not received the same attention as microbeads. The general thought associates the use of glitter with extraordinary and rare events, in reality, its presence in everyday life is much more ubiquitous than one might think. The main objective of this preliminary study was to create a mini product survey with the aim of analyzing the distribution and composition of glitter in the local market of the city of Trieste (Italy), thus creating a starting point for larger future studies. The analysis of a real context served as a snapshot for the description of the phenomenon, from which useful information was obtained: glitter is everywhere, cheap, disperses easily in the environment, is made of different materials, often has sharp-edged shapes, and mainly affects sensitive audiences, such as children. It is time to put glitter in the spotlight
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