Browsing by Author "Cravo, Alexandra"
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- Atlas of environmental risk of water quality for portuguese marinasPublication . Neves, Maria C.; Cravo, AlexandraThis study applies the pressure-state-response (PSR) model to assess the envirenmental risk of marinas along de coast of mainland Portugal.
- Bioaccumulation of metals in the soft tissue of Patella aspera: application of metal/shell weight indicesPublication . Cravo, Alexandra; Bebianno, Maria JoãoPatella aspera limpets were taken from a marine clean site (MCS) and an estuarine contaminated site (ECS). The concentrations of Fe, Mn, Zn, Cu, Cd, Ni and Co were determined individually over the available size range. Since there were significant differences in the soft tissue weight between populations, but shell characteristics were similar (length and weight), metal/shell weight indices (MSI) were calculated in order to compare populations. For both populations iron, zinc and manganese/shell weight indices were consistently higher, in the order Fe[Zn[Mn than those of Cu, Ni, Co and Cd. The results exhibited a marked intra- and interpopulation variability. The highest intra-variability was observed at ECS, particularly where a strong effect of shell weight upon the metal accumulation in the soft tissue was evident. Due to this effect, the comparison of populations was carried out between three selected shell weight ranges representative of light shells (0.45e1.95 g), intermediate shells (2.95e4.45 g) and heavy shells (5.45e 7.33 g). The results indicate that, in general, MSI at ECS (a sewage contaminated site), except for Cd, was higher than at MCS possibly reflecting a higher environmental bioavailability of these metals. The resolution between populations was higher when the smallest range of limpets was considered and it decreased with the increase of shell weight. The highest discrimination amongst populations was found for zinc/shell weight index that showed much higher values than those of Mn, Cu, Cd, Ni and Co/shell weight indices, and spatial differentiation between populations persisted amongst the selected shell weight ranges.
- Biomarker responses of the clam ruditapes decussatus exposed to a complex mixture of environmental stressors under the influence of an urban wastewater-treatment plantPublication . Silva, Sofia; Cravo, Alexandra; Ferreira, Cristina; Correia, Cátia; Almeida, Cristina M. M.To evaluate the potential impact of an urban wastewater-treatment plant on Ria Formosa coastal lagoon, a sentinel species, the clam Ruditapes decussatus, was exposed along a gradient of the effluent's dispersal for 1 mo. Three exposure sites were selected to study the responses of 3 biomarkers: electron transport system, acetylcholinesterase, and lipid peroxidation. As complementary data, morphometric measurements, condition index, and lipid and protein content were considered together with in situ physicochemical characterization of the sites (temperature, salinity, pH, and dissolved oxygen). Electron transport system activity levels were between 35.7 and 50.5 nmol O-2/min g protein, acetylcholinesterase activity levels ranged from 2.6 to 3.8 nmol/min g protein, and lipid peroxidation ranged from 174.7 to 246.4 nmol malondialdehyde/g protein. The exposure sites shaped the response not only of biomarkers but also of "health" parameters (protein, lipids, and condition index). Lipid peroxidation was the most responsive biomarker also associated with electron transport system, especially at the closest site to the urban wastewater-treatment plant. Because of the presence of complex mixtures of contaminants in urban effluents, biomarker responses can provide valuable information in environmental assessment. However, it is vital to identify all biological and ecological factors induced by the natural life cycle of clams. Abiotic factors can mask or overlap the response of biomarkers and should be considered in a multibiomarker approach. (C) 2020 SETAC
- Development of a multiresidue method for the determination of 24 pharmaceuticals in clams by QuEChERS and liquid chromatography-triple quadrupole tandem mass spectrometryPublication . Rodrigues, Joao; Albino, Stephanie; Silva, Sofia; Cravo, Alexandra; Cardoso, Vitor Vale; Benoliel, Maria Joao; Almeida, Cristina M. M.Data on different therapeutic classes of pharmaceutical compounds (PhCs) in clams or other bivalves living in natural conditions are scarce. The aim of this work was the optimization and validation of a method for the determination of PhCs in clams for further evaluation of any potential human exposure risk due to their consumption. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach is proposed for sample clean-up and concentration of 24 PhCs in clams, with subsequent analysis by liquid chromatography-tandem mass spectrometry. This method showed a good linear range for all PhCs with determination coefficients (r(2)) between 0.9949 and 0.9993 and coefficients of variation (CVm) lower than 5.5%. This method allowed the quantification of target compounds at trace concentration levels (ngg(-1)), being the most abundant PhC in clam caffeine. This PhC was detected in more than 70% of samples with concentrations ranging from 0.10 to 12ngg(-1) wet weight.
- Dissolved oxygen dynamics in Ria Formosa Lagoon (South Portugal) - A real time monitoring station observatoryPublication . Cravo, Alexandra; Rosa, Alexandra; Jacob, J.; Correia, CátiaDissolved oxygen (DO) is considered one of the most important environmental variables of water quality. This work aimed to provide, for the first time, insights regarding DO dynamics on a representative site of the productive Ria Formosa coastal lagoon, south Europe, using a real time monitoring station observatory (acquiring data every 15 min) deployed for a period of two and a half years. This comprehensive data set represents an added value contributing to a better understanding of the DO variability throughout analyzing semidiurnal, daily, fortnightly tidal cycles (spring tide vs. neap tide), seasonal and interannual periods. This observational station was able to capture distinct temporal signatures, including episodic upwelling and meteorological events advancing the knowledge about the functioning of Ria Formosa. DO was highly variable presenting an evident seasonal distribution with the maximum concentration in spring and the minimum in summer night periods. Critical values < 5 mg/L were recorded only in 3% of the global data set with negligible hypoxia events, showing infrequent DO stressful conditions in the study area. In addition, the disclosure of its did dynamics over long periods, provided by this data set, allows to determine the impact of biological activity upon the DO variability and related ecosystem metabolism behavior (autotrophic vs. heterotrophic), through the metric estimation of Net Ecosystem Metabolism (NEM). NEM in the study area revealed to be slightly heterotrophic along one year of observation, reflecting the median percentage of DO saturation (93%). The acquired data set is highly valuable and can contribute to Ria Formosa management and protection, which is imperative for building knowledge-based societies.
- DNA damage as a biomarker of genotoxic contamination in Mytilus galloprovincialis from the south coast of PortugalPublication . Catarina Almeida, Ana; G. Pereira, Catarina; Gomes, Tânia; Bebianno, Maria João; Cravo, AlexandraDNA damage was evaluated in the haemolymph of Mytilus galloprovincialis from nine sites along the south coast of Portugal using the comet assay. DNA damage was low, in the same range of sites considered to suffer low impact from genotoxic contaminants. Even so, differences between sites, seasons and genders were found. Highest values were in mussels from the main estuaries and the fishery harbour, reflecting higher genotoxin levels, whereas the lowest values can be used as a baseline for future work. Non-contaminant related factors (e.g. temperature and oxygen) were also shown to influence DNA damage. Between seasons, highest values were in summer related not only to the increase of tourism in this region (∼10-fold), but also to temperature. Between genders, males were found to be more sensitive. The condition index was also generally higher in summer. Lipid peroxidation, another damage biomarker, was measured in gills to assess if there is any association between the responses of both biomarkers and if they are similarly affected by the same environmental conditions. LPO like DNA damage was higher in summer. This work confirms that DNA damage is a sensitive biomarker to discriminate genotoxic contamination, even in areas considered to suffer low impact from genotoxins.
- Dynamics of CO2, CH4, and N2O in Ria Formosa coastal lagoon (southwestern Iberia) and export to the Gulf of CadizPublication . Sierra, A.; Ortega, T.; Forja, J.; Rodrigues, M.; Cravo, Alexandra; Correia, CátiaA first characterization of greenhouse gases had been carried out to study their role and impact in a productive transitional coastal system of the southern Portugal – Ria Formosa lagoon. To this purpose, the partial pressure of CO2 (pCO2) and the concentration of dissolved CH4 and N2O have been measured. Two surveys were carried out during 2020, at low tide under typical conditions of Spring (March) and end of Summer (October). The samplings sites were distributed along the costal lagoon covering: i) inner areas with strong human impact (influence of different flows of treated wastewater discharges); and ii) main channels in connection with the main inlets to study the exchanges with the ocean. In general, the highest values of the three greenhouse gases were found at the inner studied areas, especially affected by the disposal of treated effluents from wastewater treatment plans, in October. The mean water - atmosphere fluxes of the CO2, CH4 and N2O are positive, showing that the study
- Effects of climate change and anthropogenic pressures in the water quality of a coastal lagoon (Ria Formosa, Portugal)Publication . Rodrigues, Marta; Rosa, Alexandra; Cravo, Alexandra; Jacob, J.; Fortunato, André B.Understanding how climatic and anthropogenic drivers will influence coastal lagoons is fundamental to guarantee their preservation and sustainability. The Ria Formosa (coastal lagoon, South coast of Portugal) is a very important ecosystem that supports diverse economic activities in the region. The 3D coupled hydrodynamic-biogeochemical model SCHISM was validated and used to assess the influence of climate change and anthropogenic pressures on the water quality of the Ria Formosa. Five scenarios were simulated: reference scenario (S0), mean sea level rise (SLR) of 0.5 m (S1), increase of the air temperature of 1.68 °C (S2), increase of the outflow from the wastewater treatment plants (WWTP) by 50% (S3) and a combined scenario (S4). Results suggest that SLR of 0.5 m promotes an increase of 0.5-3 in the salinity near the area of influence of the WWTP. SLR decreases the inorganic nutrient concentrations in these areas by about 40-60%, due to an increase of the dilution. In contrast, the increase of the outflow from the WWTP by 50% increases the nutrients concentrations by about 20-40%. The increase of the air temperature alone by 1.68 °C increases the water temperature by 0-1 °C. The combined scenario suggests antagonist effects in the nutrient concentrations. Overall, the trophic index (TRIX) of the lagoon calculated for the scenarios exhibits only minor differences relative to the reference scenario, except in some areas near the WWTP discharges. In these areas, TRIX tends to increase with the increase of the outflow from the WWTP in scenario S3. These results provide further insight into the response of coastal lagoons, and the Ria Formosa in particular, to future changes and contribute to support their management.
- Evaluation of sediment toxicity in different Portuguese estuaries: ecological impact of metals and polycyclic aromatic hydrocarbonsPublication . Serafim, M.A.; Company, Rui; Lopes, Belisandra; Pereira, Catarina; Cravo, Alexandra; Fonseca, V. F.; França, S.; Bebianno, Maria João; Cabral, H. N.Estuaries are exposed to multiple sources of different pollutants which tend to be trapped in sediments. Estuarine sediments can become reservoirs of contaminants that under certain circumstances may be released back to the water column, increasing their availability to the biota. Therefore, assessing sediment quality, of which toxicity testing is one of the lines-of-evidence, is a key element in ecological risk assessment strategies for these ecosystems. The use of Vibrio fischeri as luminescence bacteria is particularly effective in evaluating contaminated sediment. In this study, the ecotoxicity of sediments from five Portuguese estuaries (Aveiro, Tejo, Sado, Mira and Guadiana), was evaluated with a bioassay considering the 50% bioluminescence reduction of V. fischeri bacterium (EC50). Also, the levels of metals and polycyclic aromatic hydrocarbon contaminants (PAHs) were determined in the same sites. Moreover the Sediment Quality Guideline Quotient index (SQG-Q) was assessed for all sediments. The EC50 values varied significantly between estuaries but were strongly correlated with the metal concentrations in the different sites. In general Tejo estuary show higher toxicity levels compared to the other estuaries (5-min EC50 values of 5.6 mg mL(-1)). The integration of sediment contamination data shows that regarding the metallic contamination all sites are moderately impacted, with a higher SQG-Q in the Tejo estuary. On the other hand, when this index is applied to the PAHs levels, all sites are considered unimpacted. This suggests that metal contaminants are the most significant cause of toxicity in these sediments. Nevertheless, other factors can be relevant for this outcome due to the geochemical complexity of estuarine sediments (which affects contaminant speciation and bioavailability) and probably the presence of multiple xenobiotics in these sediments. (c) 2013 Elsevier Ltd. All rights reserved.
- Export of dissolved and suspended matter from the main estuaries in South Portugal during winter conditionsPublication . Correia, C.; Torres, A. F.; Rosa, A.; Cravo, Alexandra; Jacob, J.; de Oliveira Junior, L.; Garel, ErwanEstuaries are essential drivers of primary productivity in coastal waters through the export of dissolved and suspended material. This study aims at quantifying this fertilization process at the two main estuaries in South Portugal, where typical low river discharge conditions occur in winter due to strong flow regulation by upstream dams and seldom-local rain events. Data were collected across the channel of the lower Arade (10/01/2018) and Guadiana (04/02/2019) estuaries during a semi-diurnal tidal cycle with intermediate tidal ranges (1.5 m and 2.2 m, respectively). Current velocity records were completed with hourly water quality measurements (temperature, salinity, pH, dissolved oxygen, suspended solids, chlorophyll a and nutrients) for determination of the along channel fluxes and residual mass transport of dissolved and suspended matter across the channel sections. The results show that the two estuaries were characterized by distinct water circulation patterns and tidal properties (e.g., standing wave at the Arade, mixed wave at the Guadiana). The concentration of dissolved and particulate matter displayed a general similar anti-phase pattern of variations with tidal height at both sites. The corresponding fluxes were generally strongest during the ebb phase. Thus, the residual mass transport was seaward, indicating that both estuaries contribute to fertilize adjacent coastal waters by exporting nutrients (order of kg), chlorophyll a (order of kg) and suspended solids (up to tons). Moreover, transport differences at both estuaries reflect specific discharge flow and environmental conditions as well as contamination sources close to the study areas. In particular, the signatures of a discharge event from a water treatment plant at the Arade and of coastal upwelling at the Guadiana were identified.