We report the concentration of 13 elements in the muscle and liver of 17 coastal fish species of ... more We report the concentration of 13 elements in the muscle and liver of 17 coastal fish species of the Bijagós Archipelago, Guinea-Bissau, and link element concentrations to trophic ecology as assessed by carbon (δ13C) and nitrogen (δ15N) stable isotopes. We found higher concentrations of Hg, Fe, Mn, Cu, Zn, Se and As in liver as compared to muscle tissue, and the opposite pattern for Sr and Ca in all fish species. The concentration of Hg and Se in muscle samples increased significantly with δ15N, suggesting a biomagnification of these elements in this food chain. The concentrations of Ca and Sr, Fe and Cr, Ca and Mn, and Fe and Mn were positively correlated to each other in more than 50% of the studied species. Fish constitute the most important animal protein source for people in Guinea-Bissau, and thus assessing the concentrations of potentially toxic elements is relevant for human health.
Wild fish (Cyprinus carpio, Mugil cephalus, Platichthys flesus) from an estuary of the NE Atlanti... more Wild fish (Cyprinus carpio, Mugil cephalus, Platichthys flesus) from an estuary of the NE Atlantic coast were investigated for plastic contamination (N = 128). From the 1289 particles recovered from fish samples, 883 were plastics. Among these, 84% were fibres and 97% were microplastics. Thirty-six polymers were identified. The number of microplastics (mean ± SD) per individual fish (MP/fish) was 8 ± 6 in C. carpio, 10 ± 9 in M. cephalus and 2 ± 2 in P. flesus. The means of MP/fish per body site were 6 ± 7 in gastrointestinal tract, 0.5 ± 1.1 in gills, 0.3 ± 0.7 in liver and 0.6 ± 1.2 in muscle samples. A few large fibres in liver (≤ 4841 μm) and muscle (≤ 5810 μm) samples were found. The results evidence the existence of high fish contamination by microplastics and reinforce the need of further research on plastic pollution in estuaries.
The present study reports the quantity, shape, colour and chemical properties of microplastics (M... more The present study reports the quantity, shape, colour and chemical properties of microplastics (MP) and MP-like in whole soft tissues of the mussel Mytilus spp. collected in January and February 2019 from four natural banks in the Portuguese coast. Three sites are located in estuarine areas influenced by anthropogenic pressures and freshwater discharges, and one in the coast far from urbanised areas. An alkaline digestion (KOH) of biological tissues was used and a polymeric identification of 20% of the visually sorted particles was achieved using the Fourier-transform mid-infrared spectroscopy (FT-MIR). MP and MP-like concentrations ranged from 0.54 to 3.0 items g-1 without significant differences among the sites. Particle size varied from 36 to 4439 μm, being fibers the most abundant shape (50%) followed by films (22%) and spherules (18%). FT-MIR revealed that 69% of the analysed particles were plastic, being identified six polymers and two polymeric blends, and 32% were cellulose-based materials. Fibers identified in mussel tissues were mainly composed of cotton and viscose (74%). This study emphasizes the importance of the polymer's spectroscopic identification after microscopic observation to recognise MP.
Marine toxins in bivalves pose an important risk to human health, and regulatory authorities thro... more Marine toxins in bivalves pose an important risk to human health, and regulatory authorities throughout the world impose maximum toxicity values. In general, bivalve toxicities due to paralytic shellfish toxins (PSTs) above the regulatory limit occur during short periods, but in some cases, it may be extended from weeks to months. The present study examines whether cockles (Cerastoderme edule), mussels (Mytilus galloprovincialis) and razor shells (Solen marginatus) naturally exposed to a bloom of Gymnodinium catenatum activated or suppressed biochemical responses as result of the presence of PSTs in their soft tissues. Toxins (C1þ2, C3þ4, GTX5, GTX6, dcSTX, dcGTX2þ3 and dcNEO) and a set of biomarkers (ETS, electron transport system activity; GLY, glycogen; PROT, protein; SOD, superoxide dismutase; CAT, catalase; GPx, glutathione peroxidase; GST, glutathione Stransferases; LPO, lipid peroxidation; reduced (GSH) and oxidized (GSSG) glutathione contents and AChE, acetylcholinesterase activity) were determined in the three bivalve species. Specimens were harvested weekly in Aveiro lagoon, Portugal, along thirteen weeks. This period included three weeks in which bivalve toxicity exceeded largely the regulatory limit and the subsequence recovery period of ten weeks. Biochemical performance of the surveyed species clearly indicated that PSTs induce oxidative stress and neurotoxicity, with higher impact on mussels and razor shells than in cockles. The antioxidant enzymes CAT and GPx seemed to be the biomarkers better associated with toxin effects.
Environmental Science and Pollution Research, 2021
Mercury is a very toxic metal that persists and accumulates in the living organisms present in th... more Mercury is a very toxic metal that persists and accumulates in the living organisms present in the aquatic systems and its elimination is an urgent need. Two green ( Ulva intestinalis and Ulva lactuca ), brown ( Fucus spiralis and Fucus vesiculosus ), and red ( Gracilaria sp. and Osmundea pinnatifida ) marine macroalgae were tested for mercury removal from saline waters. The ability of each species was evaluated to the initial mercury concentrations of 50, 200, and 500 μg dm -3 along 72 h. In general, all species exhibited good performances, removing 80.9–99.9% from solutions with 50 μg dm -3 , 79.3–98.6% from solutions with 200 μg dm -3 , and 69.8–97.7% from solutions containing 500 μg dm -3 of mercury. Among the macroalgae, Ulva intestinalis showed the highest affinity to mercury and it presented an uptake ability up to 1888 μg g -1 of Hg(II) and bioconcentration factors up to 3823, which proved its promising potential on Hg removal. Graphical abstract
et al., Negligible effect of potentially toxic elements and rare earth elements on mercury remova... more et al., Negligible effect of potentially toxic elements and rare earth elements on mercury removal from contaminated waters by green, brown and red living marine macroalgae, Science of the Total Environment (2020),
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Toxicity by PSTs in bivalves from estuarine and coastal waters of Portugal was examined. • Irregu... more Toxicity by PSTs in bivalves from estuarine and coastal waters of Portugal was examined. • Irregular multi-annual variations over 23 years considering 4 species and 6 areas • Peak toxicities in autumn/winter and occasionally in summer • Episodes of mussel and cockle toxicities connected in three estuarine systems. • Toxicity episodes of cockle and wedge clam connected despite toxin biotransformation.
h i g h l i g h t s g r a p h i c a l a b s t r a c t Simple methodology for quantify mercury at ... more h i g h l i g h t s g r a p h i c a l a b s t r a c t Simple methodology for quantify mercury at concentrations currently found in waters. Direct analysis of Hg on the Fe 3 O 4 @-SiO 2 SiDTC nanoparticles using a mercury analyser. 10 mg L À1 of nanoparticles can extract more than 90% of the total Hg in waters. The LOD achieved is lower than values reported for other magnetic materials.
The Manila clam Ruditapes philippinarum is an invasive bivalve in Europe, widely distributed, wit... more The Manila clam Ruditapes philippinarum is an invasive bivalve in Europe, widely distributed, with a great ability to tolerate a broad range of environmental conditions. Despite the ability to reflect contamination, its suitability as bioindicator is not consensual. This study provided clarification on this issue by evaluating the ability of R. philippinarum to signalise trace element contamination in an estuary chronically impacted by metals and metalloids (Tagus estuary, Portugal). A multidimensional approach was carried out in two differently contaminated sites (Barreiro-BAR; Alcochete-ALC) in warm and cold periods, combining sediment contamination, bioaccumulation of trace elements (As, Cd, Pb and Hg), and a battery of oxidative stress biomarkers in two R. philippinarum organs (digestive gland and gills). Sediments from BAR exhibited higher concentrations of all the elements than those from ALC, in line with the anthropogenic pressures identified for both estuarine areas. Likewise, clams from BAR showed higher concentrations of As and Pb in the digestive gland (cold period) and Pb in the gills (warm and cold periods) in comparison with ALC. These results suggest the capacity of R. philippinarum to reflect external levels of exposure to those elements into tissue loads. However, an opposite spatial variation was consistently found for Hg accumulation in the digestive gland and gills in both periods, as well as for Cd in the gills in the warm season. The results reinforce the idea that trace element accumulation patterns depend not only on the external bioavailability, but also on the toxicokinetics that is trace element-specific. Despite the two contrasting patterns found for bioaccumulation in R. philippinarum (mainly Pb vs. Hg), oxidative stress parameters were able to signalise BAR as the most impacted area. In fact, the digestive gland of BAR clams exhibited higher GST activity and GSHt levels (in both sampling periods) and SOD activity (warm season), presumably to cope with the enhanced accumulation of Pb and As. Moreover, variations of gills' CAT and SOD activities (warm period) agreed with the elevated accumulation of Pb at BAR. Overall, the characteristics of this invasive species could lead to a biased interpretation of the environmental quality status, particularly when based on trace element bioaccumulation only, reinforcing the need to adopt a multi-level/-species approach on environmental assessment studies.
This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós ar... more This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.
Deficit of Chemical Elements in Industrial Production: The Importance of Secondary Sources. The E... more Deficit of Chemical Elements in Industrial Production: The Importance of Secondary Sources. The European Union has classified rare earth elements as critical raw materials of high economic value and commercial interest, essential for the needs associated with technological development. These elements are difficult to obtain (mining and subsequent processing) which, associated with negative environmental impacts and high supply risk due to growing demand and the current hegemony of China in the field of supply, makes it pertinent to explore alternative technologies to obtain these elements. For this purpose, we evaluated the potential of live macroalgae to remove and concentrate rare earths from industrial waste as an economic and ecological alternative to conventional methods for obtaining them. As an example, special focus was given to the concentration of these elements from waste fluorescent lamps.
The status of Óbidos Lagoon (Portugal) was assessed combining water quality, sediment quality, an... more The status of Óbidos Lagoon (Portugal) was assessed combining water quality, sediment quality, and oxidative stress responses in female shore crab Carcinus maenas. Two sites were surveyed in October 2005, one located in an impacted, confined inner branch (Barrosa) and another in the middle of the lagoon more influenced by the seawater input. Concentrations of ammonium and nitrate + nitrite were notably higher in Barrosa, although the differences in sediment metal contamination were minor. The availability of dissolved Mn, Cu, Ni, and Cd was higher in Barrosa, particularly in the morning, which suggests the influence of internal processes occurring near the sediment during the night. Female crabs captured at Barrosa exhibited alterations in hepatopancreas antioxidants, clearly indicating that the inner branch is a more polluted area. Crabs displayed increased activity of glutathione peroxidase, catalase, and glutathione S-transferase, as well as lipid peroxidative damage, whereas no differences were observed for total glutathione. Those significant responses were not accompanied by a significant elevation of metal levels in the hepatopancreas, suggesting that adverse effects may have been caused by the synergism of stressors.
Apple residues, banana peel, eggshell, potato peel, and sweet potato peel were tested as biosorbe... more Apple residues, banana peel, eggshell, potato peel, and sweet potato peel were tested as biosorbents to remove top priority contaminants (As, Cd, Hg, and Pb) from contaminated waters. Sorption experiments were performed using 0.5 g of each biosorbent in 1 L of natural tap water spiked with a mixture of As, Cd, Hg, and Pb at realistic concentrations (50 μg L−1), under different pH values (4.5, 6.5, and 8.5) and water salinities (0, 10, and 30). Water was sampled periodically during the 48 h of the experiments and analyzed. The analysis by scanning electron microscopy showed differences among biosorbents, mainly in pore size and fibrous factures. Fourier-transform infrared spectroscopy identified cellulose, hemicellulose, pectin, and lignin in all biosorbents, except in eggshells, which are constituted mainly by carbonates. Apart from the eggshell, whose pHPZC is 10.1, all pHPZC of the biosorbents are between 3.99 and 5.90. Results showed that the levels of all contaminants in water were considerably reduced by the biosorbents in less than 3 h (more accentuated for apple and banana peel), apart from As, whose removal never surpassed 6%. Removal of Hg (up to 99%) was much higher than for Cd (76%) and Pb (86%). Overall, the pH had no notable effect on the removal, except for Cd, while ionic strength greatly influenced the removal of Cd by all the biosorbents, and the removal of Hg by eggshell. Findings point to the feasibility of reusing these agro-industrial wastes for water treatment, allowing water reuse for different purposes, which is perfectly aligned with the European agenda strategy for the Circular Economy.
We report the concentration of 13 elements in the muscle and liver of 17 coastal fish species of ... more We report the concentration of 13 elements in the muscle and liver of 17 coastal fish species of the Bijagós Archipelago, Guinea-Bissau, and link element concentrations to trophic ecology as assessed by carbon (δ13C) and nitrogen (δ15N) stable isotopes. We found higher concentrations of Hg, Fe, Mn, Cu, Zn, Se and As in liver as compared to muscle tissue, and the opposite pattern for Sr and Ca in all fish species. The concentration of Hg and Se in muscle samples increased significantly with δ15N, suggesting a biomagnification of these elements in this food chain. The concentrations of Ca and Sr, Fe and Cr, Ca and Mn, and Fe and Mn were positively correlated to each other in more than 50% of the studied species. Fish constitute the most important animal protein source for people in Guinea-Bissau, and thus assessing the concentrations of potentially toxic elements is relevant for human health.
Wild fish (Cyprinus carpio, Mugil cephalus, Platichthys flesus) from an estuary of the NE Atlanti... more Wild fish (Cyprinus carpio, Mugil cephalus, Platichthys flesus) from an estuary of the NE Atlantic coast were investigated for plastic contamination (N = 128). From the 1289 particles recovered from fish samples, 883 were plastics. Among these, 84% were fibres and 97% were microplastics. Thirty-six polymers were identified. The number of microplastics (mean ± SD) per individual fish (MP/fish) was 8 ± 6 in C. carpio, 10 ± 9 in M. cephalus and 2 ± 2 in P. flesus. The means of MP/fish per body site were 6 ± 7 in gastrointestinal tract, 0.5 ± 1.1 in gills, 0.3 ± 0.7 in liver and 0.6 ± 1.2 in muscle samples. A few large fibres in liver (≤ 4841 μm) and muscle (≤ 5810 μm) samples were found. The results evidence the existence of high fish contamination by microplastics and reinforce the need of further research on plastic pollution in estuaries.
The present study reports the quantity, shape, colour and chemical properties of microplastics (M... more The present study reports the quantity, shape, colour and chemical properties of microplastics (MP) and MP-like in whole soft tissues of the mussel Mytilus spp. collected in January and February 2019 from four natural banks in the Portuguese coast. Three sites are located in estuarine areas influenced by anthropogenic pressures and freshwater discharges, and one in the coast far from urbanised areas. An alkaline digestion (KOH) of biological tissues was used and a polymeric identification of 20% of the visually sorted particles was achieved using the Fourier-transform mid-infrared spectroscopy (FT-MIR). MP and MP-like concentrations ranged from 0.54 to 3.0 items g-1 without significant differences among the sites. Particle size varied from 36 to 4439 μm, being fibers the most abundant shape (50%) followed by films (22%) and spherules (18%). FT-MIR revealed that 69% of the analysed particles were plastic, being identified six polymers and two polymeric blends, and 32% were cellulose-based materials. Fibers identified in mussel tissues were mainly composed of cotton and viscose (74%). This study emphasizes the importance of the polymer's spectroscopic identification after microscopic observation to recognise MP.
Marine toxins in bivalves pose an important risk to human health, and regulatory authorities thro... more Marine toxins in bivalves pose an important risk to human health, and regulatory authorities throughout the world impose maximum toxicity values. In general, bivalve toxicities due to paralytic shellfish toxins (PSTs) above the regulatory limit occur during short periods, but in some cases, it may be extended from weeks to months. The present study examines whether cockles (Cerastoderme edule), mussels (Mytilus galloprovincialis) and razor shells (Solen marginatus) naturally exposed to a bloom of Gymnodinium catenatum activated or suppressed biochemical responses as result of the presence of PSTs in their soft tissues. Toxins (C1þ2, C3þ4, GTX5, GTX6, dcSTX, dcGTX2þ3 and dcNEO) and a set of biomarkers (ETS, electron transport system activity; GLY, glycogen; PROT, protein; SOD, superoxide dismutase; CAT, catalase; GPx, glutathione peroxidase; GST, glutathione Stransferases; LPO, lipid peroxidation; reduced (GSH) and oxidized (GSSG) glutathione contents and AChE, acetylcholinesterase activity) were determined in the three bivalve species. Specimens were harvested weekly in Aveiro lagoon, Portugal, along thirteen weeks. This period included three weeks in which bivalve toxicity exceeded largely the regulatory limit and the subsequence recovery period of ten weeks. Biochemical performance of the surveyed species clearly indicated that PSTs induce oxidative stress and neurotoxicity, with higher impact on mussels and razor shells than in cockles. The antioxidant enzymes CAT and GPx seemed to be the biomarkers better associated with toxin effects.
Environmental Science and Pollution Research, 2021
Mercury is a very toxic metal that persists and accumulates in the living organisms present in th... more Mercury is a very toxic metal that persists and accumulates in the living organisms present in the aquatic systems and its elimination is an urgent need. Two green ( Ulva intestinalis and Ulva lactuca ), brown ( Fucus spiralis and Fucus vesiculosus ), and red ( Gracilaria sp. and Osmundea pinnatifida ) marine macroalgae were tested for mercury removal from saline waters. The ability of each species was evaluated to the initial mercury concentrations of 50, 200, and 500 μg dm -3 along 72 h. In general, all species exhibited good performances, removing 80.9–99.9% from solutions with 50 μg dm -3 , 79.3–98.6% from solutions with 200 μg dm -3 , and 69.8–97.7% from solutions containing 500 μg dm -3 of mercury. Among the macroalgae, Ulva intestinalis showed the highest affinity to mercury and it presented an uptake ability up to 1888 μg g -1 of Hg(II) and bioconcentration factors up to 3823, which proved its promising potential on Hg removal. Graphical abstract
et al., Negligible effect of potentially toxic elements and rare earth elements on mercury remova... more et al., Negligible effect of potentially toxic elements and rare earth elements on mercury removal from contaminated waters by green, brown and red living marine macroalgae, Science of the Total Environment (2020),
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Toxicity by PSTs in bivalves from estuarine and coastal waters of Portugal was examined. • Irregu... more Toxicity by PSTs in bivalves from estuarine and coastal waters of Portugal was examined. • Irregular multi-annual variations over 23 years considering 4 species and 6 areas • Peak toxicities in autumn/winter and occasionally in summer • Episodes of mussel and cockle toxicities connected in three estuarine systems. • Toxicity episodes of cockle and wedge clam connected despite toxin biotransformation.
h i g h l i g h t s g r a p h i c a l a b s t r a c t Simple methodology for quantify mercury at ... more h i g h l i g h t s g r a p h i c a l a b s t r a c t Simple methodology for quantify mercury at concentrations currently found in waters. Direct analysis of Hg on the Fe 3 O 4 @-SiO 2 SiDTC nanoparticles using a mercury analyser. 10 mg L À1 of nanoparticles can extract more than 90% of the total Hg in waters. The LOD achieved is lower than values reported for other magnetic materials.
The Manila clam Ruditapes philippinarum is an invasive bivalve in Europe, widely distributed, wit... more The Manila clam Ruditapes philippinarum is an invasive bivalve in Europe, widely distributed, with a great ability to tolerate a broad range of environmental conditions. Despite the ability to reflect contamination, its suitability as bioindicator is not consensual. This study provided clarification on this issue by evaluating the ability of R. philippinarum to signalise trace element contamination in an estuary chronically impacted by metals and metalloids (Tagus estuary, Portugal). A multidimensional approach was carried out in two differently contaminated sites (Barreiro-BAR; Alcochete-ALC) in warm and cold periods, combining sediment contamination, bioaccumulation of trace elements (As, Cd, Pb and Hg), and a battery of oxidative stress biomarkers in two R. philippinarum organs (digestive gland and gills). Sediments from BAR exhibited higher concentrations of all the elements than those from ALC, in line with the anthropogenic pressures identified for both estuarine areas. Likewise, clams from BAR showed higher concentrations of As and Pb in the digestive gland (cold period) and Pb in the gills (warm and cold periods) in comparison with ALC. These results suggest the capacity of R. philippinarum to reflect external levels of exposure to those elements into tissue loads. However, an opposite spatial variation was consistently found for Hg accumulation in the digestive gland and gills in both periods, as well as for Cd in the gills in the warm season. The results reinforce the idea that trace element accumulation patterns depend not only on the external bioavailability, but also on the toxicokinetics that is trace element-specific. Despite the two contrasting patterns found for bioaccumulation in R. philippinarum (mainly Pb vs. Hg), oxidative stress parameters were able to signalise BAR as the most impacted area. In fact, the digestive gland of BAR clams exhibited higher GST activity and GSHt levels (in both sampling periods) and SOD activity (warm season), presumably to cope with the enhanced accumulation of Pb and As. Moreover, variations of gills' CAT and SOD activities (warm period) agreed with the elevated accumulation of Pb at BAR. Overall, the characteristics of this invasive species could lead to a biased interpretation of the environmental quality status, particularly when based on trace element bioaccumulation only, reinforcing the need to adopt a multi-level/-species approach on environmental assessment studies.
This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós ar... more This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.
Deficit of Chemical Elements in Industrial Production: The Importance of Secondary Sources. The E... more Deficit of Chemical Elements in Industrial Production: The Importance of Secondary Sources. The European Union has classified rare earth elements as critical raw materials of high economic value and commercial interest, essential for the needs associated with technological development. These elements are difficult to obtain (mining and subsequent processing) which, associated with negative environmental impacts and high supply risk due to growing demand and the current hegemony of China in the field of supply, makes it pertinent to explore alternative technologies to obtain these elements. For this purpose, we evaluated the potential of live macroalgae to remove and concentrate rare earths from industrial waste as an economic and ecological alternative to conventional methods for obtaining them. As an example, special focus was given to the concentration of these elements from waste fluorescent lamps.
The status of Óbidos Lagoon (Portugal) was assessed combining water quality, sediment quality, an... more The status of Óbidos Lagoon (Portugal) was assessed combining water quality, sediment quality, and oxidative stress responses in female shore crab Carcinus maenas. Two sites were surveyed in October 2005, one located in an impacted, confined inner branch (Barrosa) and another in the middle of the lagoon more influenced by the seawater input. Concentrations of ammonium and nitrate + nitrite were notably higher in Barrosa, although the differences in sediment metal contamination were minor. The availability of dissolved Mn, Cu, Ni, and Cd was higher in Barrosa, particularly in the morning, which suggests the influence of internal processes occurring near the sediment during the night. Female crabs captured at Barrosa exhibited alterations in hepatopancreas antioxidants, clearly indicating that the inner branch is a more polluted area. Crabs displayed increased activity of glutathione peroxidase, catalase, and glutathione S-transferase, as well as lipid peroxidative damage, whereas no differences were observed for total glutathione. Those significant responses were not accompanied by a significant elevation of metal levels in the hepatopancreas, suggesting that adverse effects may have been caused by the synergism of stressors.
Apple residues, banana peel, eggshell, potato peel, and sweet potato peel were tested as biosorbe... more Apple residues, banana peel, eggshell, potato peel, and sweet potato peel were tested as biosorbents to remove top priority contaminants (As, Cd, Hg, and Pb) from contaminated waters. Sorption experiments were performed using 0.5 g of each biosorbent in 1 L of natural tap water spiked with a mixture of As, Cd, Hg, and Pb at realistic concentrations (50 μg L−1), under different pH values (4.5, 6.5, and 8.5) and water salinities (0, 10, and 30). Water was sampled periodically during the 48 h of the experiments and analyzed. The analysis by scanning electron microscopy showed differences among biosorbents, mainly in pore size and fibrous factures. Fourier-transform infrared spectroscopy identified cellulose, hemicellulose, pectin, and lignin in all biosorbents, except in eggshells, which are constituted mainly by carbonates. Apart from the eggshell, whose pHPZC is 10.1, all pHPZC of the biosorbents are between 3.99 and 5.90. Results showed that the levels of all contaminants in water were considerably reduced by the biosorbents in less than 3 h (more accentuated for apple and banana peel), apart from As, whose removal never surpassed 6%. Removal of Hg (up to 99%) was much higher than for Cd (76%) and Pb (86%). Overall, the pH had no notable effect on the removal, except for Cd, while ionic strength greatly influenced the removal of Cd by all the biosorbents, and the removal of Hg by eggshell. Findings point to the feasibility of reusing these agro-industrial wastes for water treatment, allowing water reuse for different purposes, which is perfectly aligned with the European agenda strategy for the Circular Economy.
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