Browsing by Author "Sousa, Vânia Serrão"
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- Chronic toxicity of polystyrene nanoparticles in the marine mussel Mytilus galloprovincialisPublication . Gonçalves, Joanna M.; Sousa, Vânia Serrão; Teixeira, Margarida Ribau; Bebianno, MariaNanoplastics (NP) (1–100 nm) are a growing global concern, and their adverse effects in marine organisms are still scarce. This study evaluated the effects of polystyrene nanoplastics (10 μg/L; 50 nm nPS) in the marine mussel Mytilus galloprovincialis after a 21 – day exposure. The hydrodynamic diameter and zeta potential of nPS were analysed, over time, in seawater and ultrapure water. A multibiomarker approach (genotoxicity (the comet assay) was assessed in mussel haemocytes, and the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)), biotransformation enzyme (glutathione – S – transferase (GST)), and oxidative damage (LPO)) was assessed in gills and digestive glands to evaluate the toxicity of nPS towards mussels. In seawater, aggregation of nPS is favoured and consequently the hydrodynamic diameter increases. Genotoxicity was highly noticeable in mussels exposed to nPS, presenting a higher % tail DNA when compared to controls. Antioxidant enzymes are overwhelmed after nPS exposure, leading to oxidative damage in both tissues. Results showed that mussel tissues are incapable of dealing with the effects that this emerging stressor pursues towards the organism. The Integrated Biomarker Response index, used to summarise the biomarkers analysed into one index, shows that nPS toxicity towards mussels are both tissue and time dependent, being that gills are the tissue most compromised.
- Tertiary urban wastewater treatment with microalgae natural consortia in novel pilot photobioreactorsPublication . Morais, Etiele; Amaro Marques, José Carlos; Cerqueira, Ricardo; Dimas, Cláudia; Sousa, Vânia Serrão; Gomes, Nuno; Ribau Teixeira, Margarida; Nunes, Luís; Varela, João; Barreira, LuísaThe aim of this work was to evaluate the efficiency of the new GreenDune photobioreactors for tertiary wastewater treatment, treated wastewater reuse and biomass application, using naturally occurring microalgae consortia. The study was conducted on a pilot installation in a wastewater treatment plant in Portugal and different operational conditions were tested. The system was capable to remove up to 95% of NH4+, the main pollutant in wastewater after secondary treatment using hydraulic retention times as low as 24 h. The application of a non-conservative scenario allowed the reuse of treated wastewater for seed production, and irrigation of naturally restricted use areas. The produced biomass was rich in proteins and carbohydrates with potential for biofuel production such as biogas or use as biofertilizers, closing the energy and nutrients cycle. Finally, the life cycle assessment of both the GreenDune and existing nitrification/denitrification systems were compared revealing that the operation of the GreenDune are more environmentally favourable than the existing system.