Browsing by Author "Carreira, S."
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- 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.
- Development of histopathological indices in a commercial marine bivalvePublication . Costa, Pedro M.; Carreira, S.; Costa, Maria Helena; Caeiro, SandraBivalve histopathology is an acknowledged tool in environmental toxicology studies, however geographically restricted, limited to a few species and still lacking the degree of detail needed to develop effective (semi)quantitative approaches. A first-time detailed histopathological screening was performed on grooved carpet shell clams collected from commercial shellfish beds in distinct coastal ecosystems of the Southern Portuguese coast: two parted sites within an impacted estuary (S1 and S2), an inlet channel of a fish farm at a considered pristine estuary (site M) and a site allocated in a clean coastal lagoon (A). A total of thirty histopathological lesions and alterations were analysed in the gills and digestive glands following a weighted condition indices approach, including inflammation-related responses, necrosis, neoplastic diseases and parasites. Digestive glands were consistently more damaged than gills, except for animals collected from site M, where the most severe lesions were found in both organs, immediately followed by S2. Clams from sites S1 and A were overall the least damaged. Neoplastic diseases were infrequent in all cases. Inflammation-related traits were some of the most common alterations progressing in animals enduring severe lesions such as digestive tubule (diverticula) and intertubular tissue necrosis. Some alterations, such as lipofuscin aggregates within digestive tubule cells, did not relate to histological lesions. Granulocytomas only occurred in heavily infected tissues. Animals from M and A presented the highest infections in the digestive gland, especially by protozoa. Gill infections were more similar between sites. Still, the level of infection does not account for all histopathological lesions in either organ. Overall, the results are in accordance with environmental parameters, such as distance to pollution sources, sediment type and hydrodynamics, and show that the combination of multiple histopathological features in these clams provides good sensitivity for inter-site distinction even when low or moderate anthropogenic impacts are at stake.
- Ecotoxicological heterogeneity in transitional coastal habitatsPublication . Carreira, S.; Costa, Pedro M.; Martins, M.; Lobo, J.; Costa, Maria Helena; Caeiro, SandraTransitional waterbodies, such as estuaries, are highly diversified environments with respect to ecology, geophysics, and nature of anthropogenic impacts. This spatial heterogeneity may pose important constraints when developing monitoring programmes for aquatic pollution. The present study compared three distinct coastal ecosystems located in Southern Portugal (subjected to different anthropogenic stressors), namely, two estuaries and a coastal lagoon, through the characterisation of sediment contamination and a biomarker approach to an important commercial clam (Ruditapes decussatus) obtained from local fishing grounds. The results showed high heterogeneity of sediment contamination for both estuaries and a marked distinction between industrially and agriculturally influenced areas as well as between natural and artificialized sites. Hydrodynamics and oceanic influence (in essence dictating sediment type) play a major role in environmental quality. Environmental heterogeneity constituted an important confounding factor for biomarker analysis in the clams’ digestive glands since the animals appeared to respond to their immediate surroundings’ characteristics rather than the geographical area where they were collected from, despite the relative distance to pollution hot spots. Still, oxidative stress biomarkers (lipid peroxidation and catalase activity) could correlate with each other and to both organic and metallic contamination, whereas metallothionein- like protein induction failed to correlate to any class of sediment toxicants (albeit metals being the most representative pollutants) and appeared to be strongly affected (unlike the previous) by clam size and probably other unknown internal and external variables, among which contaminant interactions should play a major role.
- Public perceptions of hazards associated with Brazil nuts (Bertholletia excelsa) : evaluation of risk within an European contextPublication . Carreira, S.; Cunha, Luís Miguel; Moura, Ana Pinto de; Lima, R. C.; Souza, M. P.; Souza Filho, Theophilo Alves de ; Silva, T. N.; Pedrozo, Eugenio A.One of the most important economic plants of the Amazon is the Brazil nut (Bertholletia excelsa). Brazil nuts for international trade are mainly obtained from wild collection rather than from plantations, often cited as one of the most important products of extractive reserves in Amazonia. The European Commission (2003/493/EC) has imposed strict regulations on the import from Brazil of Brazil nuts in their shells, as the shells have been found to contain high levels of aflatoxins, which can lead to liver cancer. This may have a negative impact on the Brazilian exports of shelled Brazil nuts, due to possible public awareness. The aim of the present research is to assess public perceptions regarding Brazil nuts and to contrast these with other nuts in general through the use of the Portuguese version of the Perceived Food Risk Index (PFRI). A sample of 418 consumers was drawn through a door-to-door interview using a random route walk procedure and following a quota sampling controlled for sex, age and location. Consumers were asked to choose the most relevant quality and preservation characteristics and to identify their consumption patterns for Brazil nuts and for nuts in general. Risk perception was evaluated over ten risk characteristics, for each of the following hazards: i) aflatoxins; ii) biological contaminants; iii) organoleptic changes; iv) fragments and strange bodies and v) microbial contamination. Additionally, subjects were asked to rate the probability of each hazard occurring in Brazil nuts or in nuts in general. Results show high consumptions of nuts in general, and a reduced consumption of Brazil nuts, although with low differences on the dimensions of risk perception. Concluding, this work adds to knowledge about the perceptions of risk connected to Brazil nuts consumption, namely that consumers perceive Brazil nuts as safe as nuts in general.