Browsing by Author "Costa, Maria Helena"
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- Adaptive-participative sustainability indicators in marine protected areas: designPublication . Marques, A. S.; Ramos, Tomás B.; Caeiro, Sandra; Costa, Maria HelenaRecently there has been an effort to put in practice integrated management plans in Marine Protected Areas (MPA) not only because of their high natural and cultural importance but also due to usual conflicts related to local activities. These plans should include the use of adaptive sustainability indicators that reflect stakeholders concerns, and community interests, allowing a better assessment, management and reporting. An adequate set of indicators for the MPA should help their managers to improve management policies in order to achieve better decision making processes. This study aimed to develop a set of adaptive-participative sustainability indicators (SDI) for the assessment, management and reporting of MPAs that include, through the all process, the participation of local stakeholders at every levels, integrating the stakeholders knowledge and perceptions about the SDI meaning and a self-assessment of the SDI state produced also by the stakeholders. The proposed approach was tested in Luiz Saldanha’s Marine Park, located in South East of Portugal between the municipalities of Sesimbra and Setúbal. The framework to design the SDI comprised four phases: i) an international analysis of SDI sets for coastal zones and MPAs; ii) a participatory process, where the stakeholders had the possibility to state their concerns through an online and face to face questionnaire surveys about the strengths and weaknesses of the MPA; iii) an analysis conducted by a team of experts to reach a set of indicators that include the main relevant aspects of environmental, socioeconomic, and governance issues, taking into account the information from the first two phases and iv) a workshop and questionnaires held to assess the stakeholders’ global views and perception about the selected set of indicators and each indicator’s relative importance. This study showed the importance of a dynamic participative process involving the local stakeholders. It is concluded that this methodology allows a better understanding of each indicator by the local stakeholders and how it could respond to their concerns. It should also help the MPA managers, to define the most suitable management actions and monitor the management plan itself.
- An integrative assessment to determine the genotoxic hazard of estuarine sediments: combining cell and whole-organism responsesPublication . Costa, Pedro M.; Pinto, Miguel; Vicente, Ana; Gonçalves, Cátia; Rodrigo, Ana; Louro, Henriqueta; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoThe application of the Comet assay in environmental monitoring remains challenging in face of the complexity of environmental stressors, e.g., when dealing with estuarine sediments, that hampers the drawing of cause-effect relationships. Although the in vitro Comet assay may circumvent confounding factors, its application in environmental risk assessment (ERA) still needs validation. As such, the present work aims at integrating genotoxicity and oxidative DNA damage induced by sediment-bound toxicants in HepG2 cells with oxidative stress-related effects observed in three species collected from an impacted estuary. Distinct patterns were observed in cells exposed to crude mixtures of sediment contaminants from the urban/industrial area comparatively to the ones from the rural/riverine area of the estuary, with respect to oxidative DNA damage and oxidative DNA damage. The extracts obtained with the most polar solvent and the crude extracts caused the most significant oxidative DNA damage in HepG2 cells, as measured by the formamidopyrimidine-DNA glycosylase (FPG)-modified Comet assay. This observation suggests that metals and unknown toxicants more hydrophilic than polycyclic aromatic hydrocarbons may be important causative agents, especially in samples from the rural part of the estuary, where oxidative DNA damage was the most significant. Clams, sole, and cuttlefish responded differentially to environmental agents triggering oxidative stress, albeit yielding results accordant with the oxidative DNA damage observed in HepG2 cells. Overall, the integration of in vivo biomarker responses and Comet assay data in HepG2 cells yielded a comparable pattern, indicating that the in vitro FPG-modified Comet assay may be an effective and complementary line-of-evidence in ERA even in particularly challenging, natural, scenarios such as estuarine environments.
- Assessing heavy metal contamination in Sado EstuaryPublication . Caeiro, Sandra; Costa, Maria Helena; Ramos, Tomás B.; Fernandes, F.; Silveira, N.; Coimbra, Ana Paula; Medeiros, G.; Painho, MarcoThe Sado Estuary in Portugal is a good example of a site where human pressures and ecological values collide with each other. An overall contamination assessment has never been conducted in a way that is comprehensible to estuary managers. One of the aims of this work was to select different types of index to aggregate and assess heavy metal contamination in the Sado Estuary in an accessible manner. Another aim was to use interpolation surfaces per metal to compare and gauge the results of the indices and to assess the contamination separately per metal. Seventy-eight stations were sampled within the main bay of the estuary and a set of heavy metals and metalloids was established, Cd, Cu, Pb, Cr, Hg, Al, Zn and As. The sediment fine fraction content, organic matter and redox potential were also analysed. Various indices for contamination, background enrichment and ecological risk were used, tested, compared and performance-evaluated. All metals and metalloids were strongly correlated, and the indices appear to reflect heavy metal variability satisfactorily. Difficulties were found in some indices regarding boundary definition (minimum and maximum) and comparability with other estuaries, thus better methods of standardization should be a priority issue. According to the index that has the highest performance score within the group of ecological risk indices – the Sediment Quality Guideline Quotient – only 3% of the stations are highly contaminated and register a high potential for observing adverse biological effects, whereas 47% display moderate contamination. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate. For spatial and source evaluation per metal, interpolation surfaces should also be used.
- Assessment of sediment contamination in an impacted estuary: differential effects and adaptations of sentinel organisms and implications for biomonitoringPublication . Costa, Pedro M.; Gonçalves, C.; Martins, M.; Rodrigo, Ana; Carreira, S.; Costa, Maria Helena; Caeiro, SandraEstuarine pollution is reflected in the concentration of toxicants in sediments, depending on their geochemical properties, since sediments trap substances from the water column, either dissolved or bound to suspended matter. However, determining risk of sediment contaminants to biota has many constraints. For such reason, integrative approaches are keystone. Taking the Sado estuary (SW Portugal) as a case study, contrasted to a reference estuary (the Mira) within the same geographical location, the present study aimed at integrating sediment contamination with the effects and responses to pollutants in distinct benthic organisms with commercial and ecological value.
- Assessment of the genotoxic potential of contaminated estuarine sediments in fish peripheral blood: laboratory versus in situ studiesPublication . Costa, Pedro M.; Neuparth, Teresa S.; Caeiro, Sandra; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; DelValls, T. Ángel; Costa, Maria HelenaJuvenile Senegalese soles (Solea senegalensis) were exposed to estuarine sediments through 28-day laboratory and in situ (field) bioassays. The sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or ‘‘comet’’) assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to sediment contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of sediment contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with sediment contamination levels. While field assays may provide more ecologically relevant data, the multiple environmental variables may produce sufficient background noise to mask the true effects of contamination.
- Avaliação do potencial citotóxico e genotóxico de contaminantes de sedimentos do Estuário do Sado numa linha celular humanaPublication . Pinto, Miguel; Costa, Pedro M.; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria JoãoO presente estudo integra-se num projeto mais amplo que visa avaliar o risco ambiental – que inclui os riscos ecológicos e para a saúde humana - associado a este ambiente estuarino contaminado. Em particular, este estudo teve como objetivo caracterizar o potencial citotóxico e genotóxico de sedimentos colhidos em vários locais de pesca do Estuário do Sado numa linha celular humana, tendo em vista uma avaliação de eventuais efeitos nefastos para a saúde humana.
- Benthic biotope index for classifying habitats in the sado estuary: PortugalPublication . Caeiro, Sandra; Costa, Maria Helena; Goovaerts, Peter; Marco, Painho; Flavio, MartinsAn integration of sediment physical, chemical, biological, and toxicity data is necessary for a meaningful interpretation of the complex sediment conditions in the marine environment. Assessment of benthic community is a vital component for that interpretation, yet their evaluation is complex and requires a large expenditure of time and funds. Thus, there is a need for new tools that are less expensive and more understandable for managers. This paper presents a benthic biotope index to predict from physical and chemical variables the occurrence of macrobenthic habitats. Parameters such as sediment type, organic matter, depth, and hydrodynamic parameters were selected, through a discriminant analysis, to compute the index. Other authors have used multivariate methods to determine the benthic biotopes for Sado Estuary. The index proved to be a valid tool to classify and assess the spatial patterns of benthic habitat and to synthesize stress biotope gradients.
- Biochemical endpoints on juvenile Solea senegalensis exposedPublication . Costa, Pedro M.; Caeiro, Sandra; Diniz, Mário S.; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; DelValls, T. Ángel; Costa, Maria HelenaJuvenile Solea senegalensis were exposed to fresh sediments from three stations of the Sado estuary (Portugal) in 28-day laboratory assays. Sediments revealed distinct levels of total organic matter, fine fraction, redox potential, trace elements (arsenic, cadmium, chromium, copper, nickel, lead and zinc) and organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and a pesticide: dichloro diphenyl trichloroethane). Organisms were surveyed for contaminant bioaccumulation and induction of two hepatic biochemical biomarkers: metallothionein (MT) and cytochrome P450 (CYP1A), as potential indicators of exposure to metallic and organic contaminants, respectively. Using an integrative approach it was established that, although bioaccumulation is in general accordance with sediment contamination, lethality and biomarker responses are not linearly dependent of the cumulative concentrations of sediment contaminants but rather of their bioavailability and synergistic effects in organisms. It is concluded that metals and organic contaminants modulate both MT and CYP1A induction and it is suggested that reactive oxygen species may be the link between responses and effects of toxicity.
- Can the integration of multiple biomarkers and sediment geochemistry aid solving the complexity of sediment risk assessment?: a case study with a benthic fishPublication . Costa, Pedro M.; Caeiro, Sandra; Vale, Carlos; Delvalls, T. Ángel; Costa, Maria HelenaSurveying toxicity of complex geochemical media as aquatic sediments often yields results that are either difficult to interpret or even contradictory to acknowledged theory. Multi-level biomarkers were investigated in a benthic fish exposed to estuarine sediments through laboratory and in situ bioassays, to evaluate their employment either in ecological risk assessment or in more mechanistic approaches to assess sediment-bound toxicity. Biomarkers reflecting lesions (such as genotoxicity or histopathology), regardless of their low or absent specificity to contaminants, are efficient in segregating exposure to contaminated from uncontaminated sediments even when classical biomarkers like CYP1A and metallothionein induction are inconclusive. Conversely, proteomics and gene transcription analyses provided information on the mechanics of toxicity and aided explaining response variation as a function of metabolic imbalance and impairment of defences against insult. In situ bioassays, although less expedite and more affected by confounding factors, produced data better correlated to overall sediment contamination.
- Delineation of estuarine management areas using multivariate geostatistics: the case of Sado EstuaryPublication . Caeiro, Sandra; Goovaerts, Pierre; Painho, Marco; Costa, Maria HelenaThe Sado Estuary is a coastal zone located in the south of Portugal where conflicts between conservation and development exist because of its location near industrialized urban zones and its designation as a natural reserve. The aim of this paper is to evaluate a set of multivariate geostatistical approaches to delineate spatially contiguous regions of sediment structure for Sado Estuary. These areas will be the supporting infrastructure of an environmental management system for this estuary. The boundaries of each homogeneous area were derived from three sediment characterization attributes through three different approaches: (1) cluster analysis of dissimilarity matrix function of geographical separation followed by indicator kriging of the cluster data, (2) discriminant analysis of kriged values of the three sediment attributes, and (3) a combination of methods 1 and 2. Final maximum likelihood classification was integrated into a geographical information system. All methods generated fairly spatially contiguous management areas that reproduce well the environment of the estuary. Map comparison techniques based on κ statistics showed that the resultant three maps are similar, supporting the choice of any of the methods as appropriate for management of the Sado Estuary. However, the results of method 1 seem to be in better agreement with estuary behavior, assessment of contamination sources, and previous work conducted at this site.