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Browsing by Author "Costa, Maria Helena"

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  • An integrative assessment to determine the genotoxic hazard of estuarine sediments: combining cell and whole-organism responses
    Publication . Costa, Pedro Manuel; Pinto, Miguel; Vicente, Ana M.; Gonçalves, Cátia; Rodrigo, Ana P.; Louro, Henriqueta; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria João
    The 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 The 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.
    2014-12-10Journal article Open access Show more
  • Avaliação do potencial citotóxico e genotóxico de contaminantes de sedimentos do Estuário do Sado numa linha celular humana
    Publication . Pinto, Miguel; Costa, Pedro Manuel; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria João
    O 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.
    2014-12Journal article Open access Show more
  • Avaliação do risco ambiental e para a saúde pública de um ambiente estuarino contaminado
    Publication . Pinto, Miguel; Louro, Henriqueta; Caeiro, Sandra; Costa, Pedro; Costa, Maria Helena; Lavinha, João; Silva, Maria João
    O estuário do rio Sado é um ecossistema de elevado valor ecológico e económico. Apesar de ter vindo a ser afetado ao longo dos anos por várias fontes de poluição de origem urbana, industrial e agrícola, continua ainda a ser, para a população local, um local privilegiado para atividades piscícolas e agrícolas. Contudo, existe uma preocupação relacionada com a potencial bioacumulação de contaminantes nas partes edíveis de espécies estuarinas ou de produtos agrícolas locais que entrarão assim na cadeia alimentar humana, podendo representar um problema de saúde pública. O presente estudo integra-se num projeto mais amplo que visa avaliar os riscos ambientais e para a saúde humana, associados a esse 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. Observaram-se efeitos citotóxicos e genotóxicos diferentes em amostras de sedimentos derivadas da margem esquerda vs. direita do estuário que se podem correlacionar com diferenças nos níveis e tipos de contaminantes identificados nessas amostras. Estes refletem, provavelmente, as diversas pressões no ecossistema derivadas de uma área urbana e industrializada (margem esquerda) vs. uma área de intensa atividade agrícola (margem direita). A observação de que amostras de sedimentos estuarinos induzem efeitos citotóxicos e genotóxicos em células humanas, em consonância com os efeitos também detetados em espécies estuarinas, enfatiza a preocupação sobre o impacto do consumo de espécies contaminadas na saúde das populações locais e reforça a necessidade de serem tomadas medidas no sentido de reduzir e remediar a poluição desta área estuarina.
    2013-05-23Conference object Open access Show more
  • Bromine occurrence in Portuguese cabbage from center region of Portugal before and after forest fires
    Publication . Ventura, Marta; Delgado, Inês; Coelho, Inês; Gueifão, Sandra; Matos, Ana Sofia; Martins, Marta; Costa, Maria Helena; Castanheira, Isabel
    Bromine (Br) is one of the main halogens of the periodic table and has been classified as emerging contaminant due to its persistence in the environment, bio-magnification properties and risk to human health [1]. The main goal of this work was to evaluate Bromine contents in Portuguese cabbage (Brassica Oleracea var. Costata DC), in the center region of Portugal before and after forest fires. This vegetable is one of the most consumed by the Portuguese population and is recognized as an accumulator of contaminants from the air and from soils. All cabbage samples were collected in the center region of Portugal. Before forest fire 3 Portuguese cabbage were collected in 9 different zones in a total of 27 samples (Control Group-CG) and used as a control. After forest fire (AFF), 3 Portuguese cabbage were collected in 8 zones over four periods of time (first campaign in August of 2017, second campaign in December of 2017, third campaign in April of 2018 and fourth campaign in August of 2018), in a total of 96 samples. Bromine contents was determined by inductively coupled plasma mass spectrometry (ICP-MS), preceded by an alkaline extraction with 25% ammonium tetramethylhydroxide (TMAH). The results were obtained through analytical procedures that reflected the quality assurance requirements described in ISO / IEC 17025: 2005. The concentration was expressed in mg Br/kg cabbage. The amount of Br in CG (mean of 27 samples) was 2 mg/kg. Most of the cabbage samples collected after forest fire presented concentrations above CG, with the following values; the first campaign (4.8 mg/kg), the second campaign (4.0 mg/kg) and the fourth campaign (4.5 mg/kg). The only campaign AFF that presented values below CG was the third one (1.7 mg/kg). Results before forest fires (CG) and after forest fire (4 campaigns) using One Way ANOVA pointed successfully on the existing statistical differences between bromine concentrations in CG and AFFs collection (p-value < 0.05). Through the Least significant differences (LSD) test the 1st and 4th campaigns (AFF) were the only ones that evidenced significant differences with the CG. After the forest fires, the 3rd campaign showed significantly lowest values when compared with the 1st and the 4th campaigns. However, these results do not pose risk to the Portuguese population, according to the commission regulation (EC) No 839/2008, wherein the value of bromide in brassicas is 30mg/kg [2].
    2019-11Conference object Restricted access Show more
  • Bromine, arsenic, cadmium, and lead in several key food groups: an assessment of relative risk
    Publication . Ventura, Marta; Cardoso, Carlos; Bandarra, Narcisa Maria; Delgado, Inês; Coelho, Inês; Gueifão, Sandra; Ribeiro, Mariana; Costa, Maria Helena; Castanheira, Isabel
    This study endeavoured to provide an overview of the bromine, Br, arsenic (As, a metalloid) and metal (cadmium, Cd, and lead, Pb) relative risk associated with the consumption of relevant food groups (lean fish, fatty fish, bivalves, cephalopods, fresh fruit, dried fruit, and green vegetables) in Portugal. Though As, Cd, and Pb have been frequently studied, a comprehensive overview applying the same state-of-the-art methodology to a wide array of foods is missing. Besides, there is a large deficit of content information and risk assessment studies on Br. Thus, it is important to apply a mathematically realistic and innovative methodology (extreme value theory) to recent and accurate databases for the aforementioned food groups and elements. Best fits to Br, As (total), Cd, and Pb concentrations were attained through different functions, ranging from the normal distribution to the Weibull distribution. A semi-probabilistic risk assessment approach on the basis of four alternative scenarios (one monthly meal; one weekly meal; three weekly meals; one daily meal) showed low relative risk regarding Br and Pb in the selected food groups, including bivalves, which contained the highest Br and Pb contents. With respect to total As, high relative risk values were calculated for seafood, but it should be emphasized that this As is overwhelmingly organic, thus presenting low risk. For Cd, substantial relative risk associated with bivalves’ and cephalopods’ consumption, particularly with one or more weekly meal(s), was found. However, the current study enables us to compare between the relative risk of the studied food groups and scenarios, and other studies encompassing the whole diet and following long-term dietary patterns are needed for the assessment of absolute risk.
    2018-12-20Journal article Restricted access Show more
  • Bromo, um contaminante de preocupação emergente em couve portuguesa
    Publication . Ventura, Marta; Delgado, Inês; Coelho, Inês; Ribeiro, Mariana; Ferreira, Marta; Costa, Maria Helena; Castanheira, Isabel
    O bromo é um dos principais halogéneos da tabela periódica e tem vindo a ser classificado como contaminante de preocupação emergente, porque devido à sua bio-magnificação pode constituir um risco para a saúde humana. Os compostos bromados são contaminantes não biodegradáveis que se acumulam nos diferentes níveis tróficos da cadeia alimentar. O objetivo deste trabalho foi avaliar os teores de bromo em amostras de couve portuguesa (Brassica Oleracea var. costata DC), uma hortícola do género brássica bastante consumida pela população portuguesa. Foram recolhidas cento e dezassete amostras durante o período 2015-2017 em diferentes locais representativos de cada distrito de Portugal, em dois períodos de colheita. O teor de bromo foi determinado por espectrometria de massa com plasma indutivo acoplado (ICP-MS), precedido por uma extração alcalina com Tetrametilhidróxido de amónia (TMAH). Os valores de bromo encontrados na primeira colheita estavam compreendidos entre 0,5 e 14,5 mg/kg e na segunda colheita os valores observados estavam compreendidos entre 1,0 e 7,8 mg/kg. As amostras foram organizadas de acordo com a Nomenclatura de Unidades Territoriais NUTS II para Portugal e constatou-se que as regiões com valores mais elevados de bromo foram a Região do Algarve e a Região Autónoma da Madeira. Em comparação com o LMR (limite máximo de resíduos) para os teores do ião brometo em alimentos da espécie brássica (30 mg/kg) verificou-se que nenhuma das amostras analisadas ultrapassou esse valor estipulado. No entanto, serão necessários estudos adicionais sobre a avaliação da exposição, bem como sobre a toxicologia deste contaminante, para que entidades reguladoras possam avaliar a pertinência da revisão da legislação em vigor.
    2018-12Journal article Open access Show more
  • Characterization of cytotoxic and genotoxic effects of contaminated sediments from the Sado Estuary and potential human health risk
    Publication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Costa, Maria Helena; Caeiro, Sandra; Lavinha, João; Silva, Maria João
    The river Sado Estuary (W Portugal) is affected by various sources of pollution, such as heavy-industry, urbanism, mining, agriculture and maritime traffic. Mostly classified as a natural reserve, it also remains a privileged site for fishing activities performed by the local population, who not only consume but distribute their fishery. The present study is part of a broader project whose objective is to evaluate the environmental and human health risks associated with the estuarine benthic environment. This study aims to assess the cytotoxic and genotoxic potential of sediments from several local fishing areas of the Sado Estuary. Sediments were collected from four geochemically distinct and potentially contaminated sites of the Sado Estuary: sites C and P from the northern shore and sites E and A from the southern shore. A previously characterized sample (F) from the northern shore was added as a positive control. Total organic and inorganic contaminants were extracted with a mixture of methanol:dichloromethane (1:2) and recovered in DMSO. Cytotoxicity and genotoxicity were evaluated through the neutral red uptake assay and by the alkaline comet (coupled with DNA repair endonucleases) and the micronucleus assays, respectively, in the human HepG2 cell line. Cells were exposed for 48h to concentrations of each extract ranging from 0.1 to 20µl/ml of culture medium. A dose-related decrease in cell viability was observed for extracts F, P and E, indicating sediment contaminant-driven cytotoxicity, whereas no effect was observed for extracts C and A. No significant genotoxicity was observed for extract C, while extract F was clearly genotoxic, as expected. A significant increase in the level of DNA and chromosome damage was observed, by the comet and micronucleus assays, respectively, for sub cytotoxic concentrations of extracts P and E. The level of DNA damage was accentuated following treatment with the DNA repair endonuclease FPG, suggesting the existence of oxidative DNA damage. Extract A was genotoxic in the micronucleus assay and in the comet assay only after FPG treatment. Negative results from sample C leads us to consider it as potential clean reference for further studies. Moreover, sediment contamination analysis revealed high levels of metals in all samples except C, whereas only sample P exhibited high levels of known genotoxic polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and DDTs, similar to the previously described for sample F. The differential cytotoxicity and genotoxicity observed in samples from the northern (P) and southern areas (E and A) of the Sado Estuary probably reflects different pressures from a urban and heavy industrialized area versus an intense agricultural area, respectively. The observation that sediment samples have cytotoxic and genotoxic effects, together with the knowledge that contaminants can be accumulated in the edible parts of estuarine species or local agricultural products entering the human food chain, raise concern about a hazardous impact on the health of exposed populations that must be assessed. Work supported by the Foundation for Science and Technology (ref. PTDC/SAU-ESA/100107/2008).
    2012-05-30Conference object Open access Show more
  • Cytotoxic and genotoxic assessment of potentially contaminated sediments from the Sado Estuary
    Publication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria João
    Previous studies have shown that the river Sado Estuary (W Portugal) is highly susceptible to contamination due to anthropogenic activity. In fact, sizable concentrations of metals, pesticides and polycyclic aromatic hydrocarbons have been measured in sediments from various points of the estuary. Those compounds may be absorbed by aquatic species, making it a public health issue when entering the human food chain. The purpose of this study was to assess the cytotoxic and genotoxic potential of sediment extracts in a human cell line, through the neutral red uptake assay and the alkaline comet assay, respectively. Three sediment samples were collected: two in potentially contaminated sites (samples C and F, Sado Estuary) and one in a putative control station (sample M, Mira Estuary). The overall contaminants were extracted from the three samples. HepG2 cells were exposed for 48h to serial dilutions of each extract (ranging from 0.01 to 2μl). A dose-related decrease in cell viability was observed for samples F and M (from 0.1 and 0.5μl, respectively, up to 2μl), indicating a toxic effect caused by the complex contaminants mixtures. However, no genotoxicity could be observed for any sample in the experimental conditions used. Further studies are underway with different exposure times and different endpoints for a more complete assessment of the extracts' genotoxic properties.
    2011-07Conference object Open access Show more
  • Cytotoxic and genotoxic potential of sediments from the Portuguese Mira-River Estuary
    Publication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro Manuel; Costa, Maria Helena; Caeiro, Sandra; Lavinha, João; Silva, Maria João
    The Mira-River Estuary (SW Portugal) although being a protected natural area has been affected by urban pollution from the village of Vila Nova de Milfontes (VNMF) and by contaminants from farming and aquaculture activities. The present study is part of a broader project comprising the evaluation of environmental and human health risks from potentially contaminated estuaries and aims to assess the cytotoxic and genotoxic potential of sediments from the Mira-River Estuary. Sediments were collected from two sites: Mf located near VNMF, and M near an aquaculture discharge channel. Organic and inorganic contaminants were extracted as four fractions using: methanol:dichloromethane (F1), dichloromethane (F2), hexane (F3) and methanol (F4) and recovered in DMSO. Cytotoxicity and genotoxicity were evaluated through the neutral red assay and the comet (coupled with DNA repair endonucleases) and micronucleus assays, respectively, in the human hepatoma-derived (HepG2) cell line. Contaminants analysis was carried out by GC-MS and ICP-MS for organic and metallic contaminants, respectively. A dose-related decrease in cell viability indicating cytotoxicity was observed for sample M, extracts F1, F2 and F4. A significant increase in the level of DNA and chromosome damage was observed for sub-cytotoxic doses of extracts F1, F2 and F3, by the comet and micronucleus assays, respectively. Additionally, oxidative DNA damage was also detected in the same samples. All Mf fractions failed to induce significant cytotoxic or genotoxic effects. These data agree with contaminants characterisation, given that a higher level of known genotoxic metals and PAHs were found in sample M but not in Mf. Overall, our results suggest that urban pollution of Mira-River Estuary sediments might be less hazardous than contamination from the aquaculture and agriculture activities, raising the question of the safe consumption of aquatic species grown in aquacultures, and of aquacultures as potential sources of aquatic pollution.
    2013-03-03Conference object Open access Show more
  • Determining oxidative and non-oxidative genotoxic effects driven by estuarine sediment contaminants on a human hepatoma cell line
    Publication . Pinto, Miguel; Costa, Pedro; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria João
    Estuarine sediments may be reservoirs of hydrophilic and hydrophobic pollutants, many of which are acknowledged genotoxicants, pro-mutagens and even potential carcinogens for humans. Still, studies aiming at narrowing the gap between ecological and human health risk of sediment-bound contaminant mixtures are scarce. Taking an impacted estuary as a case study (the Sado, SW Portugal), HepG2 (human hepatoma) cells were exposed in vitro for 48 h to extracts of sediments collected from two areas (urban/industrial and Triverine/agricultural), both contaminated by distinct mixtures of organic and inorganic toxicants, among which are found priority mutagens such as benzo[a]pyrene. Comparatively to a control test, extracts of sediments from both impacted areas produced deleterious effects in a dose-response manner. However, sediment extracts from the industrial area caused lower replication index plus higher cytotoxicity and genotoxicity (concerning total DNA strand breakage and clastogenesis), with emphasis on micronucleus induction. On the other hand, extracts from the rural area induced the highest oxidative damage to DNA, as revealed by the FPG (formamidopyrimidine-DNA glycosylase) enzyme in the Comet assay. Although the estuary, on its whole, has been classified as moderately contaminated, the results suggest that the sediments from the industrial area are significantly genotoxic and, furthermore, elicit permanent chromosome damage, thus potentially being more mutagenic than those from the rural area. The results are consistent with contamination by pro-mutagens like polycyclic aromatic hydrocarbons (PAHs), potentiated by metals. The sediments from the agriculture-influenced area likely owe their genotoxic effects to metals and other toxicants, probably pesticides and fertilizers, and able to induce reactive oxygen species without the formation of DNA strand breakage. The findings suggest that the mixtures of contaminants present in the assayed sediments are genotoxic to HepG2 cells, ultimately providing a useful approach to hazard identification and an effective line-of-evidence in the environmental monitoring of anthropogenically-impacted coastal ecosystems.
    2014-04-15Journal article Restricted access Show more