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- Short-term variability of multiple biomarker response in fish from estuaries: Influence of environmental dynamicsPublication . Fonseca, V.F.; França, S.; Vasconcelos, R.P.; Serafim, M.A.; Company, Rui; Lopes, Belisandra; Bebianno, Maria João; Cabral, H.N.Short-term variability in biomarker responses and the effects of temperature and salinity variation were explored in three fish species (Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps) occurring in the Tejo estuary. Short-term variability in biomarkers was observed in all species although no pattern was discerned over time (days to weeks). Antioxidant enzymes activity (superoxide dismutase (SOD) and catalase (CAT)) showed low temporal variability, indicating some constancy or baseline level in antioxidant responses. Only CAT activity in S. senegalensis was correlated with temperature, suggesting that exposure to contaminants triggered antioxidant acclimation. Higher short-term variability was observed in xenobiotic biotransformation enzymes activity (phase I ethoxyresorufin O-deethylase (EROD) and phase II glutathione S-transferase (GST)). Yet a significant correlation between EROD and GST in D. labrax and S. senegalensis suggests a concomitant response to contaminants. Moreover the lack of correlation between xenobiotic biotransformation enzymes and abiotic variables on concordant time scales, suggest a high specificity of these biomarkers to chemical exposure, rather than high variability due to environmental dynamics.
- Multi-biomarker responses to estuarine habitat contamination in three fish species: Dicentrarchus labrax, Solea senegalensis and Pomatoschistus micropsPublication . Fonseca, V. F.; França, S.; Serafim, M.A.; Company, Rui; Lopes, Belisandra; Bebianno, Maria João; Cabral, H. N.Several biomarker responses were determined in three fish species, Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps, from two estuaries of the Portuguese coast, Ria de Aveiro and Tejo. Both estuaries have significant anthropogenic influences from multiple sources (industrial, agricultural and shipping activities), which was evident from sediment chemical characterization concerning metal (copper, zinc, nickel, lead and chromium) and polycyclic aromatic hydrocarbon (PAH) concentrations. Spatial variability in fish responses was observed across species for most biomarkers of exposure [the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST), and metallothionein concentrations (MT)] and effect biomarkers [lipid peroxidation (LPO), RNA to DNA ratio (R:D), protein and lipid content]. In general, the interspecific differences in biomarker responses were greater than the spatial differences, due to differences in the behavior and habitat use of the species. Nevertheless, similarities were also observed considering both chemical load and biomarker responses. In highly polluted sites fish showed in general a significant antioxidant enzyme induction, associated with decreased R:D values, while fish from the least impacted site had little enzyme induction and better condition indices (high R:D and low LPO values). EROD activity was also higher for all species in the Tejo than Ria de Aveiro estuary, despite the generally higher total PAH measured in Ria de Aveiro, most likely due to a higher proportion of 4 and 6-ring PAHs, considered more toxic than low molecular weight PAHs, in the Tejo. In conclusion, this multi-biomarker approach considering multiple species provided improved understanding of the diverse responses and effects of exposure to contaminants and the effective risk it poses for different fish species.
- A multibiomarker approach in Mytilus galloprovincialis to assess environmental qualityPublication . Cravo, Alexandra; Lopes, Belisandra; Serafim, M.A.; Company, Rui; Barreira, Luísa; Gomes, Tânia; Bebianno, Maria JoãoA multibiomarker approach was carried out for the first time in the South Portuguese Coast using Mytilus galloprovincialis, to assess environmental quality, establish if there are adverse biological responses associated to different sources of anthropogenic contamination and to determine spatial and seasonal trends. For this purpose the battery of biomarkers selected was: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx total and Se dependent), Cytochrome P450 component system, Glutathione-S-transferase (GST) and acetylcholinesterase (AChE), metallothionein (MT) and lead-delta-aminolevulinic acid dehydratase (ALAD), lipid peroxidation (LPO) and Condition Index (CI) along with the determination of PAHs and metals (Cd, Cu, Ni, Pb and Zn). Results show that despite the levels of both organic and metallic contaminants in these eight spots in the South Coast of Portugal not being particularly high compared with other contaminated/polluted sites worldwide, the selected battery of biomarkers responded efficiently to the environmental changes and allowed an environmental assessment between seasons and sites. Different spatial and seasonal responses were evident along the South Coast of Portugal, meaning that the contamination is not homogeneous. This does not only reflect different competition, origin and intensity of contamination, but also different environmental conditions (e.g. temperature, salinity). Along the South Portuguese Coast site 8 was the most contaminated, while site 2 was considered the least contaminated. Despite environmental factors possibly causing difficulties in the general interpretation of biomarker data, those that better responded to environmental contamination were CYP450, SOD-mit and T-GPx for the summation SigmaPAHs, MT (digestive gland) for metals (especially Cu), ALAD for Pb and LPO for both organic and metallic contamination. These biomarkers were also positively correlated with temperature in summer, revealing this as a more stressful/critical season. In future environmental contamination assessments there is no need to analyse the components b5, P418, NADH and NADPH of phase I MFO system, and MT in the gills, since their responses are not evident.
- Variation of metal and metallothionein concentrations in a natural population of ruditapes decussatusPublication . Bebianno, Maria João; Serafim, A.The spatial and seasonal variation of total and subcellular distribution of Cd, Cu, and Zn was followed in different tissues (gills, digestive gland, and remaining tissues) of the clam Ruditapes decussatus collected along a metal contamination gradient in the Ria Formosa lagoon (southern Portugal) and compared with metallothionein (MT) concentrations.Total metal concentrations decreased according to the sequence digestive gland > gills > remaining tissues for Cd, digestive gland approximately gills > remaining tissues for Cu and gills > digestive gland > remaining tissues for Zn. MT concentrations in these tissues decreased according to the same sequence observed for Cd. In all the tissues, the highest subcellular concentration was in the cytosol for Cd and Cu and in the pellet for Zn. Among the three metals, Cd concentrations showed the most evident spatial variation. In all tissues, total and subcellular Cd concentrations decreased from the inner parts of the lagoon toward the ocean. However, no significant spatial or seasonal variation occurred in clam tissues for the other two metals, though marginal elevated Cu concentrations were observed in the inner parts of the lagoon. Therefore, Cu subcellular distribution in clam tissues was not significantly altered by Cu changes in the lagoon and are the baseline levels for normal metabolism of this clam population. The fact that total Zn concentrations remained unchanged both spatial and seasonal suggested that these clams regulate Zn in their tissues. In the three tissues, MT bind most significantly to Cd and Cu, while Zn, although binding to MT, is preferably bound to other ligands. MT concentrations showed the same spatial and seasonal variation of Cd and were significantly related with total and heat-treated cytosolic Cd in all tissues. For Cu a significant relationship between MT and total or cytosolic Cu was only observed in the remaining tissues. No relationship was observed between MT and total or cytosolic Zn concentrations. Metals and MT concentrations increased with the increase in the condition index for the gills and the digestive gland and decreased from the remaining tissues.Cd concentrations in the gills increased only in the heat-treated cytosolic fraction while Zn in this fraction decreased. Thus Cd concentrations in this tissue displaced Zn from the MT-fraction, leading to a modification of the soluble/insoluble Zn ratio once total Zn concentrations remained unchanged. This modification reflects a perturbation in the normal metabolism in this tissue due to the excess of Cd present. With the exception of the gills, Zn subcellular distribution in the other two tissues was similar among sites and season. The model that describes the relationship between MT, metals, and weight in the gills, digestive gland and remaining tissues also indicates that Cd was the only metal that influence MT synthesis significantly in all the tissues. The induced and/or existent MT was sufficient to bind free Cd ions present in the cells, preventing any damage to cellular metabolism in this clam population. Therefore, MT in the gills and digestive gland of R. decussatus can be used as an early warning signal for Cd exposure and are a useful biomarker to assess the toxicological status of this population in the Ria Formosa lagoon.
- A multi-biomarker approach in cross-transplanted mussels Mytilus galloprovincialisPublication . Serafim, M.A.; Lopes, Belisandra; Company, Rui; Cravo, Alexandra; Gomes, Tânia; Serrão Sousa, Vânia; Bebianno, Maria JoãoThe present work integrates the active biomonitoring (ABM) concept in mussels Mytilus galloprovincialis from the South coast of Portugal transplanted during 28 days between two sites with different sources of contamination, and vice versa, in order to assess biological effects in these mussels. For that purpose a multibiomarker approach was used. The suit of biomarkers indicative of metal contamination were metallothioneins (MT) and the enzyme δ-aminolevulinic acid dehydratase (ALAD), for organic contamination mixed function oxidase system (MFO), glutathione-S-transferase (GST) and acetylcholinesterase (AChE), as oxidative stress biomarkers superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation (LPO). These biomarkers were used to determine an index to evaluate the stress levels in these two sites. Site A is strongly influenced by metallic contamination, with higher Cu, Cr and Pb in M. galloprovincialis, as well as higher MT levels, antioxidant enzymes activities and LPO concentrations, and lower ALAD activity. In site B organic compounds (PAHs) are prevalent and native mussels show higher activities of the MFO system components and GST. Transplanted mussels had significant alterations in some biomarkers that reflect the type of contaminants present in each site, which demonstrates the primary role of the environment in determining the physiological characteristics of resident mussels. Therefore the application of ABM using a battery of biomarkers turns out to be a useful approach in sites where usually complex mixtures of contaminants occurs. In this study the biomarkers that better differentiate the impact of different contaminants at each site were MT, CYP450, SOD and CAT.
- Biomarkers of exposure to metal contamination and lipid peroxidation in the benthic fish Cathorops spixii from two estuaries in South America, BrazilPublication . Azevedo, J. S.; Serafim, M. A.; Company, Rui; Braga, E. S.; Fávaro, D. I.; Bebianno, Maria JoãoBiomarkers as lipid peroxidation, metallothionein and delta-aminolevulinic acid dehydratase were determined in Cathorops spixii to compare the biological responses of this fish from estuaries with distinct anthropogenic influence. Three areas were selected in two estuaries in accordance with the levels of contamination for the polluted (Santos/São Vicente) and with the hydrodynamic characteristics for the non-polluted (Cananéia) estuary. Water characteristics and mercury levels in C. spixii confirmed a high human influence in the polluted system. In general, the biomarkers showed differences between the estuaries, suggesting disturbances in the specific cell mechanisms due to the presence of multiple xenobiotics in the contaminated system. Therefore, these biomarkers are recommended to promote more accurate information about the exposure to pollutants. Additionally, the study of the effect of the multiple xenobiotics on resident species such as the benthic fish C. spixii can favor a better assessment of the environmental quality of these systems.
- Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: A freshwater bivalve studyPublication . Company, Rui; Serafim, Angela; Lopes, Belisandra; Cravo, A.; Shepherd, T. J.; Pearson, G.; Bebianno, Maria João; Cravo, AlexandraLead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, delta-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.