Percorrer por autor "Ferreira, Isabel"
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- Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magnaPublication . Mansilha, Catarina; Silva, Poliana; Rocha, Sónia; Gameiro, Paula; Domingues, Valentina; Pinho, Carina; Ferreira, IsabelBisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children exposition to BPA contamination has been emphasized because the immaturity of their biological systems. The main aim of this study was to assess the reproductive burden of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring specie Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological tests results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (embryos per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1±4.3% to 264.7±3.8%), both in single as in multigenerational tests, in comparison with the negative control group (100.3±1.6%). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, embryo production by daphnids cultured in polypropylene and non-PC bottles, was slightly but not significantly enhanced (92.5±2.0% to 118.8±1.8%). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose-response relationship or a mixture toxicity effect.
- Environmental impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium and pesticidesPublication . Pinto, Edgar; Melo, Armindo; Mansilha, Catarina; Ferreira, Isabel
- Protective effect of Crataegus monogyna Jacq. ethanolic extracts in oxidant-induced DNA damage evaluated through comet assay with human peripheral lymphocytesPublication . Barreira, Joao; Costa, Carla; Teixeira, João Paulo; Ferreira, Isabel; Oliveira, BeatrizMuch attention of preventive medicine research is focused on natural antioxidants. This interest refers not only to isolation and identification of new biologically active molecules for the pharmaceutical industry, but also because of the emergent public interest in using crude plant extracts, such as infusions for self-medication (Krishnaiah et al., 2011). The use of antioxidants, such as the well-known polyphenolic compounds, to prevent genetic damage induced by physical or chemical agents is of considerable interest. This bioactivity might be related to their anticlastogenic effect, due to the presence of specific functional groups. Other antioxidant compounds, such as vitamins C and D, were reported for their DNA-damage decreasing effect, suggesting that reactive oxygen species may be involved in this activity (Benavente-García et al., 2004). Evaluating the antioxidant activity of natural matrices represents one of our primary research challenges (Ferreira et al., 2009). Among hundreds of studied species, Crataegus monogyna Jacq. stood out as being one of the most promising plants due to its high bioactivity. Besides the antioxidant activity, C. monogyna was also studied for the human tumour cells growth inhibitory capacity of its phenolic extracts; furthermore, individual phenolic compounds were fully characterized by high performance liquid chromatography-photo diode array detection-electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/ MS), revealing high levels of flavonols, flavones, hydroxycinnamic acid derivatives and anthocyanins (Rodrigues et al., 2012). However, there is a high limitation in examining if the detected bioactivity is actually transferred from in vitro to in vivo systems (Carocho and Ferreira, 2013).
- Simultaneous QuEChERS and DLLME extraction of pesticides in tomato samplesPublication . Melo, Armindo; Mansilha, Catarina; Pinho, Olívia; Ferreira, Isabel
- Vegetables production in NW Portugal, agriculture practices and groundwater qualityPublication . Aguiar, Ana; Melo, Armindo; Mansilha, Catarina; Ferreira, IsabelIn NW of Portugal, the region between Esposende and Vila do Conde was established into a unique system called masseiras; masseiras are small fields that were created at the beginning of XX century by removing sand from dunes. Since the 80’s sand between closed masseiras has been removed giving way for larger fields, the “enlarged masseira with greenhouses”. This region is part of vulnerable zone nº1 (VZ1). Nowadays, the masseiras have almost disappeared; they had been replaced by “enlarged masseiras with plastic greenhouses” exploited by a new generation of growers. As water quality is an indicator of agriculture practices, 8 wells were selected and water samples were collected on four dates from September 2009 to May 2010. Laboratorial analysis was performed on nitrates and 28 pesticides. The results confirm that water in VZ1 is contaminated with nitrates (as it was expected) and also with pesticides. The water was contaminated in both dug wells and drilled wells all year round. Masseiras’ wells have more nitrates than greenhouses’ wells, probably due to poor agricultural practices used by growers who still employ high quantities of fertilizers and water. Pesticides detected in water samples include some that have been sprayed in the field and others that have not. Some forbidden substances were found. Our results confirm that, in VZ1, there is a diffusion contamination, which origin is unknown. In this communication, we put in picture the history of masseiras fields: how masseiras fields have been created and how they have disappeared; what trends exist in pest management strategies and the use of fertilizers, pesticides and water resources. These results reinforce the need to change the agricultural system in this region of traditional vegetable production.