Publications (9)21.93 Total impact
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Article: Assessment of contaminants and biomarkers of exposure in wild and farmed seabass.
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ABSTRACT: This study aimed to investigate the relationships between levels of organochlorine compounds (PCBs and DDTs), polycyclic aromatic hydrocarbons (PAHs), metals and biomarkers of exposure (EROD and GST) and oxidative stress biomarkers, in wild and cultured European seabass (Dicentrarchus labrax). Additionally, the fatty acid profile was determined in muscle to assess differences between cultivated and wild specimens of marketable size. Although results pointed to relatively low concentration of contaminants, wild specimens presented enhanced accumulation of metals and cultivated specimens higher levels of organic compounds. Biomarkers were correlated with contaminants in tissues, showing that higher levels can cause effects at the biochemical level. Wild specimens have presented higher content on omega-3 fatty acids in muscle. Besides the useful application of biomarkers in wild species, this study has shown that they can also be applied to monitor biological effects in the fish farming process.Ecotoxicology and Environmental Safety 02/2010; 73(4):579-88. · 2.29 Impact Factor -
Article: Organochlorine bioaccumulation and biomarkers levels in culture and wild white seabream (Diplodus sargus).
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ABSTRACT: Persistent organic pollutants (POPs), which can accumulate in the adipose fish tissues, can enter the human food chain through the consumption of fish, and cause risk to health. The use of chemical analysis, and biochemical and cellular responses is a way to detect the impact of pollutants in aquatic systems. The purpose of this study was to investigate the levels of organochlorine compounds (polychlorinated biphenyls - PCB and p,p'-dichlorodiphenyltrichloroethane and its metabolites - tDDT) in, wild and cultivated, white seabream (Diplodus sargus), and also its biological effects that were evaluated by assessing the activity of biotransformation enzymes and genotoxic effects. To achieve that we have sampled five different size classes (I - 13 g, II - 64 g, III - 143 g, IV - 315 g and V - 441 g) of white seabream from a local aquaculture, and also a group of wild fish (375g) in order to compare accumulation and responses between cultured and wild fish. White seabream, cultured and wild, presented low levels of organochlorine content, both in liver and in muscle. Wild white seabream, in comparison to cultured ones at the marketable size, showed lower organochlorine accumulation. Biotransformation enzymes showed negative correlations with organochlorine levels in liver. Micronucleous numbers revealed that wild white seabream are not so exposed to genotoxic compounds as cultured ones.Chemosphere 10/2008; 73(10):1669-74. · 3.21 Impact Factor -
Article: Influence of the chemical structure on mobility of PCB congeners in female and male sardine (Sardina pilchardus) from Portuguese coast.
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ABSTRACT: Concentrations of 30 polychlorinated biphenyl congeners (CBs) were determined in muscle, liver and gonad tissues of female and male sardines (Sardina pilchardus) collected in February-May 2000 and September-January 2001 from purse seine vessels operating around Peniche, Portugal. The determined CBs were aggregated in four groups (I, II, III and IV), according to similarities of their chemical structures. Muscle and liver of males contained significantly higher concentrations of groups I and II than females during the final period of spawning (February-April). A less contrast was observed for the groups III and IV. This seasonal fluctuation associated with the spawning indicates that female sardines regulate the excess of CBs sequestrated during fatten period. On the contrary, levels of groups I and II were higher in males than in females indicating slower mobility of these compounds as lipids were consumed during the final period of spawning. The deficient regulation of those CBs in muscle of male sardines can not be attributed to selective transfer to gonads and subsequent excretion. Although the full explanation was not found for the different mobility of PCBs with the gender, the results provide evidence of slower elimination of group I and II congeners in male sardines.Chemosphere 10/2007; 69(3):395-402. · 3.21 Impact Factor -
Article: Evidence for higher biomagnification factors of lower chlorinated PCBs in cultivated seabass.
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ABSTRACT: Thirty three PCB congeners were analyzed in three size classes of seabass (Dicentrarchus labrax), from a semi-intensive fish farm, in food and in abiotic compartment. Water and suspended particulated matter (SPM) showed higher concentrations of lower chlorinated PCBs, whereas fish tissues and food showed higher concentrations of CB153 and CB138. In order to examine the influence of different inputs to seabass contamination, bioaccumulation factors (BAF), biota-suspended particulate matter bioaccumulation factors (BSMAF) and biomagnification factors (BMF) were calculated. In general, the log BAF and log BSMAF showed good correlations with log K(ow), for congeners with log K(ow)>6.1. In three fish size classes, PCB congeners with log K(ow)<6.1 were found at concentrations higher than what was expected based on the BAF calculated for the more hydrophobic congeners, suggesting a different contribution of sources. The application of a mass balance model for accumulation of some congeners in seabass estimated concentrations in fish 3- to 38-fold higher than the measured values, probably by overestimating gill absorption. The model was applied with other scenarios in order to maximize uptake from food, which may have a significant influence in accumulation, and not only from diet pellets. Its contribution to fish contamination for highly chlorinated PCBs may reach a maximum of 54-64%, and for lower chlorinated PCBs its contribution is lower than 20%. In this work it was proved that to reduce fish contamination the quality of the water should be controlled.Science of The Total Environment 05/2007; 377(1):36-44. · 3.29 Impact Factor -
Article: The use of the marine biotic index AMBI in the assessment of the ecological status of the Obidos lagoon (Portugal).
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ABSTRACT: This study reports the longitudinal distribution of sediment properties, including inorganic and organic contaminants, and the structure of the benthic community in Obidos lagoon, a coastal system permanently connected to the sea and with negligible freshwater sources. Sediments from the upper to central lagoon consist of fine particles (91%) and from the lower lagoon of sands (94%). Chemical composition is strongly correlated to the percentage of fine particles. Contamination is relatively low in those sediments suggesting the effect of diffuse sources. The increase in organic matter content from down- to upstream areas was associated with the dominance of opportunistic species, while sensitive and indifferent species to organic enrichment were mainly associated to the clean sandy downstream area. The marine biotic index (AMBI) was suitable for the discrimination of the biological and environmental gradients in the Obidos lagoon and was highly related with the gradient of organic matter content in this system.Marine Pollution Bulletin 12/2006; 52(11):1414-24. · 2.50 Impact Factor -
Article: PCB and DDT contamination in cultivated and wild sea bass from Ria de Aveiro, Portugal.
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ABSTRACT: Polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) and metabolites were quantified in muscle and liver of sea bass (Dicentrarchus labrax) collected in Ria de Aveiro and in two fish farms. Sea bass from natural environment showed lower levels than fish from farming, which may be partly attributed to the higher lipid content of cultivated fish. PCB congener distribution in tissues of sea bass from the two farms resembled that of diet pellets suggesting that commercial diet is a major source of PCBs. However, fish in the two sites were fed with diet of similar PCB and DDT contamination but showed distinct levels in its tissues not explained by lipid content.Chemosphere 04/2004; 54(10):1503-7. · 3.21 Impact Factor -
Article: DDT concentrations in surficial sediments of three estuarine systems in Portugal
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ABSTRACT: Levels of p,p-DDT and its metabolites in surficial sediments of Tagus and Sado Estuary and lagoon Ria Formosa varied one or two orders of magnitude. In general, p,-DDE and p,-DDD were the dominant metabolites and p,-DDT was a minor component. While concentrations of p,-DDT, p,-DDD and p,-DDE were hardly related to loss on ignition, concentrations of total DDT (tDDT) in surficial sediments of each studied system were positively correlated to that parameter. Higher contaminated samples were excluded from these relationships: a few sediment samples from the Tagus outlet channel, most of the sediments from the upper Sado Estuary, and some particulate matter samples collected in sediment traps in the adjoining area to the Ria Formosa. Concentration of tDDT appears, thus, to be related to sedimentary organic matter of these estuarine systems except near the actual sources of pollution. On the basis of the relationship slopes, one may conclude that lower Tagus Estuary is more contaminated than Ria Formosa and lower Sado Estuary.Aquatic Ecology 09/1999; 33(3):263-269. · 1.37 Impact Factor -
Article: Organochlorine bioaccumulation and biomarkers levels in culture and wild white seabream (Diplodus sargus)
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ABSTRACT: Persistent organic pollutants (POPs), which can accumulate in the adipose fish tissues, can enter the human food chain through the consumption of fish, and cause risk to health. The use of chemical analysis, and biochemical and cellular responses is a way to detect the impact of pollutants in aquatic systems. The purpose of this study was to investigate the levels of organochlorine compounds (polychlorinated biphenyls – PCB and p,p′-dichlorodiphenyltrichloroethane and its metabolites – tDDT) in, wild and cultivated, white seabream (Diplodus sargus), and also its biological effects that were evaluated by assessing the activity of biotransformation enzymes and genotoxic effects. To achieve that we have sampled five different size classes (I – 13 g, II – 64 g, III – 143 g, IV – 315 g and V – 441 g) of white seabream from a local aquaculture, and also a group of wild fish (375 g) in order to compare accumulation and responses between cultured and wild fish. White seabream, cultured and wild, presented low levels of organochlorine content, both in liver and in muscle. Wild white seabream, in comparison to cultured ones at the marketable size, showed lower organochlorine accumulation. Biotransformation enzymes showed negative correlations with organochlorine levels in liver. Micronucleous numbers revealed that wild white seabream are not so exposed to genotoxic compounds as cultured ones.Chemosphere. -
Article: Supercritical fluid extraction of organochlorines from fish muscle with different sample preparation
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ABSTRACT: Supercritical carbon dioxide was used to extract PCBs, p,p′-DDE, p,p′-DDD, p,p′-DDT and dieldrin from fillets of black scabbardfish (Aphanopus carbo). Using standards, the optimal extraction conditions of pressure and temperature were determined using the statistical method of central composite surface design. The studied temperatures ranged from 309 to 337 K and pressure from 10 to 24 MPa. It was observed that temperature do not affect significantly the extraction and, on the contrary, a significant effect was recorded for pressure. The best extraction efficiencies were obtained at pressures near 14 MPa, for all the studied compounds. To study the matrix effect on the yields, three types of raw materials were selected: fresh fillet, fresh fillet with anhydrous sodium sulphate and freeze-dried fillet. It was observed that supercritical carbon dioxide can extract efficiently the organochlorine compounds from freeze-dried fillets, but very low recoveries were obtained from fresh fillets. The pressure effect on extraction was studied for the freeze-dried samples. Three pressures were tested: 18, 22 and 26 MPa, maintaining the temperature at 328 K. Analysing the initial extraction velocities it was observed that 22 MPa was the optimal extraction pressure. The concentration of organochlorine compounds obtained by supercritical fluid extraction was, in some cases, higher than those obtained by Soxhlet extraction, using n-hexane.Journal of Supercritical Fluids The 25(2):135-142. · 2.86 Impact Factor
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Institutions
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2008–2010
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University of Porto
Porto, Distrito do Porto, Portugal
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