Browsing by Author "Pereira, Eduarda"
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- In Vitro Hepatotoxic and Neurotoxic Effects of Titanium and Cerium Dioxide Nanoparticles, Arsenic and Mercury Co-ExposurePublication . Rosário, Fernanda; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana C.; Tavares, Daniela S.; Pereira, Eduarda; Teixeira, João Paulo; Reis, Ana TeresaConsidering the increasing emergence of new contaminants, such as nanomaterials, mixing with legacy contaminants, including metal(loid)s, it becomes imperative to understand the toxic profile resulting from these interactions. This work aimed at assessing and comparing the individual and combined hepatotoxic and neurotoxic potential of titanium dioxide nanoparticles (TiO2NPs 0.75-75 mg/L), cerium oxide nanoparticles (CeO2NPs 0.075-10 μg/L), arsenic (As 0.01-2.5 mg/L), and mercury (Hg 0.5-100 mg/L) on human hepatoma (HepG2) and neuroblastoma (SH-SY5Y) cells. Viability was assessed through WST-1 (24 h) and clonogenic (7 days) assays and it was affected in a dose-, time- and cell-dependent manner. Higher concentrations caused greater toxicity, while prolonged exposure caused inhibition of cell proliferation, even at low concentrations, for both cell lines. Cell cycle progression, explored by flow cytometry 24 h post-exposure, revealed that TiO2NPs, As and Hg but not CeO2NPs, changed the profiles of SH-SY5Y and HepG2 cells in a dose-dependent manner, and that the cell cycle was, overall, more affected by exposure to mixtures. Exposure to binary mixtures revealed either potentiation or antagonistic effects depending on the composition, cell type and time of exposure. These findings prove that joint toxicity of contaminants cannot be disregarded and must be further explored.
- Integrated Use of Bioaccumulation, Genotoxic, and Haematological Endpoints to Assess the Effect of Water Remediation Strategies on Fish Health: A Complementary StudyPublication . Mieiro, Cláudia; Coelho, João; Reis, Ana Teresa; Castro, Diana; Figueira, Paula; Martinho, Filipe; Pardal, Miguel; Pereira, Eduarda; Pacheco, Mário; Lopes, CláudiaBiosorption successfully remediates saline water contaminated with legacy contaminants, but its effects on the health of marine organisms remain unclear. Therefore, our aim was to address this knowledge gap with data on the accumulation ability, as well as the cytogenetic and biochemical effects in turbot (Scophthalmus maximus). To this end, we exposed turbot for seven days to a mixture of remediated metals (Rem treatments: Cd, Hg, and Pb), with and without the presence of nanoparticles (NP), and compared them with the maximum allowable concentrations (MAC treatment) for effluent discharges. We determined the metal accumulation in the blood and kidney and evaluated haematological changes (red blood cell count, haemoglobin, and mean cell haemoglobin (MCH)) and genotoxicity (erythrocytic nuclear abnormalities assay) in the blood. The results showed that remediation with non-living macroalgae significantly reduced the metallic blood and kidney burdens in the Rem treatments. Furthermore, no genotoxic potential occurred in the Rem and MAC treatments in parallel with the reduction in MCH levels in the Rem treatments, which would reflect hematopoietic disturbances in the MAC. Our results validate biosorption remediation as we achieved a considerable reduction in metal loads while maintaining the health status of fish, highlighting the importance of testing water remediation methods in the biota.
- Simultaneous removal of trace elements from contaminated waters by living Ulva lactucaPublication . Henriques, Bruno; Teixeira, Ana; Figueira, Paula; Reis, Ana T.; Almeida, Joana; Vale, Carlos; Pereira, EduardaThis work shows the capabilities of living seaweed, Ulva lactuca, to remove As, Cd, Pb, Cu, Cr, Hg, Mn and Ni from contaminated waters. Experiments were performed with three algal doses (1.5, 3.0 and 6.0 g L-1, FW), two ionic strengths (salinity 15 and 35), and trace element concentrations corresponding to the maximum allowed values in wastewaters. The highest removals were obtained with the algal dose of 6 g L-1, with efficiencies varying between 48% for As and 98% for Hg, after 24 to 72 h. Salinity showed no effect on the removal efficiency. Overall, Elovich model was the best in describing the kinetics of the process, except for Hg, where pseudo-second-order model performed better. The use of extractions with EDTA (0.001, 0.01 to 0.1 mol L-1) has clarified that most of the Hg (≈98%) and Cr (≈80%) crossed the macroalgae walls, while Ni, Cd and As were retained at the surface (between 60 and 80%). These results support the hypothesis that macroalgae-based technologies may be a viable, cost-effective, and greener option to reduce the rejection of priority hazardous substances in contaminated waters.
- A Single Digestion Procedure for Determination of Major, Trace, and Rare Earth Elements in SedimentsPublication . Carvalho, Lina; Reis, Ana T.; Soares, Eugénio; Tavares, César; Monteiro, Rui J.R.; Figueira, Paula; Henriques, Bruno; Vale, Carlos; Pereira, EduardaThe simultaneous determination of major, trace, and rare earth elements in sediments requires the development of specific procedures to prevent interfer- ences. A single digestion method adapted from the EPA method 3051A is proposed for the quantification of 42 elements in sediments by inductively coupled plasma techniques associated with optical emission spectroscopy (ICP-OES) and mass spectrometry (ICP- MS). A combination of different acids and microwave- assisted acid extraction following hot plate extraction was tested. Evaluation of applicability range, linearity, limits of detection and quantification, selectivity, repeat- ability, intermediate precision, and trueness showed the accurate determination of all elements. Selectivity, pre- cision, and trueness values were below the criteria established by the laboratory. The applicability of the proposed method was tested in real sediment samples. For each element, difference between duplicates was lower than the corresponding repeatability limit, with the coefficients of variation ranging between 1.7 and 14%. These results point to the usefulness of this meth- od in multi-element determination of major, minor, trace, and REE in sediment samples, showing its appli- cability in environmental studies related, namely to sediment characterization, monitoring programs, assess- ment of environmental impacts, sediment provenance, and post-depositional mechanisms.