In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) and Villa Putzu (...In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin 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 between 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 muscle 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.展开更多
This study reports on the accumulation of polybrominated diphenyl ethers (PBDEs) and polychlorobiphenyls (PCBs) in the muscle tissue of 11 species of fish from the Ionian Sea (Western Mediterranean). The results are c...This study reports on the accumulation of polybrominated diphenyl ethers (PBDEs) and polychlorobiphenyls (PCBs) in the muscle tissue of 11 species of fish from the Ionian Sea (Western Mediterranean). The results are consistent with previous studies that have reported now-generalized contamination by PCBs of the Mediterranean marine environment, as well as widespread diffusion of emerging contaminants such as polybrominated diphenyl ethers (PBDEs). The Western Mediterranean Sea, from which the 11 fish species were collected, receives a heavy pollutant input from the urban and industrial areas along its coasts. Higher values of PCBs (average over 1.5 mg/kg f.w.) were observed in pelagic top predators (little tuna, bluefin tuna and swordfish). These same species also showed higher levels of PBDEs, averaging above 0.5 ng/g f.w. This puts a few fish species at the top of the food chain—such as bluefin tuna and swordfish—at particular risk, and the importance of these species in the human diet suggests the need for particular care in our food choices.展开更多
This 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. T...This 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.展开更多
This paper describes recent levels of surfactants measured in a coastal lagoon ecosystem highly stressed by human activites: the Orbetello lagoon (Southern Tuscany, Italy, Ramsar Site IT008). Significance of differenc...This paper describes recent levels of surfactants measured in a coastal lagoon ecosystem highly stressed by human activites: the Orbetello lagoon (Southern Tuscany, Italy, Ramsar Site IT008). Significance of difference among concentrations measured before and after summertime are explored in order to evaluate effects related to tourism exploitation. Among surfactants, methylene blue active anionic substances (MBAS) are selected as tracers for untreated discharges originated by domestic and urban activities. Water samplings were performed in 2011 following a randomly replicated nested logic model (n = 144). MBAS mean level of 0.070 mg.L–1 (–1) and 0.530 mg.L–1 (–1) are respectively recorded in June and October evidencing a significant increase after the touristic season. Possible MBAS concentration phenomena could be induced by different evaportaton rates among sampling stations and between winter and summer seasons and were evaluated, in this study, using water salinity as possible factor affecting samples segregations. Results evidence that differences of MBAS levels related to evaporation rates are trascurabile if compared to the variability induced by the presence of not-collected wastewater hot-spot pollution sources located closed around the urban settlement and along sandbars. Measured levels of surfactants could act negatively on living organisms both animals and plants contributing to affect Orbetello lagoon biodiversity. In this ecosystem, after the complete reorganization of urban wastewater treatment plants occured in 2008, further management actions should be focalized on reducing untreated sources of MBAS.展开更多
In 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 usi...In 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 process;nevertheless, lipid extraction from macrophytes could represent an interesting step of a much more complex biomass recycling process which could include, besides biodiesel, also, the production of other commercial materials as well as pigments and biosorbents.展开更多
文摘In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin 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 between 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 muscle 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.
文摘This study reports on the accumulation of polybrominated diphenyl ethers (PBDEs) and polychlorobiphenyls (PCBs) in the muscle tissue of 11 species of fish from the Ionian Sea (Western Mediterranean). The results are consistent with previous studies that have reported now-generalized contamination by PCBs of the Mediterranean marine environment, as well as widespread diffusion of emerging contaminants such as polybrominated diphenyl ethers (PBDEs). The Western Mediterranean Sea, from which the 11 fish species were collected, receives a heavy pollutant input from the urban and industrial areas along its coasts. Higher values of PCBs (average over 1.5 mg/kg f.w.) were observed in pelagic top predators (little tuna, bluefin tuna and swordfish). These same species also showed higher levels of PBDEs, averaging above 0.5 ng/g f.w. This puts a few fish species at the top of the food chain—such as bluefin tuna and swordfish—at particular risk, and the importance of these species in the human diet suggests the need for particular care in our food choices.
文摘This 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.
文摘This paper describes recent levels of surfactants measured in a coastal lagoon ecosystem highly stressed by human activites: the Orbetello lagoon (Southern Tuscany, Italy, Ramsar Site IT008). Significance of difference among concentrations measured before and after summertime are explored in order to evaluate effects related to tourism exploitation. Among surfactants, methylene blue active anionic substances (MBAS) are selected as tracers for untreated discharges originated by domestic and urban activities. Water samplings were performed in 2011 following a randomly replicated nested logic model (n = 144). MBAS mean level of 0.070 mg.L–1 (–1) and 0.530 mg.L–1 (–1) are respectively recorded in June and October evidencing a significant increase after the touristic season. Possible MBAS concentration phenomena could be induced by different evaportaton rates among sampling stations and between winter and summer seasons and were evaluated, in this study, using water salinity as possible factor affecting samples segregations. Results evidence that differences of MBAS levels related to evaporation rates are trascurabile if compared to the variability induced by the presence of not-collected wastewater hot-spot pollution sources located closed around the urban settlement and along sandbars. Measured levels of surfactants could act negatively on living organisms both animals and plants contributing to affect Orbetello lagoon biodiversity. In this ecosystem, after the complete reorganization of urban wastewater treatment plants occured in 2008, further management actions should be focalized on reducing untreated sources of MBAS.
文摘In 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 process;nevertheless, lipid extraction from macrophytes could represent an interesting step of a much more complex biomass recycling process which could include, besides biodiesel, also, the production of other commercial materials as well as pigments and biosorbents.
