Percorrer por autor "Caeiro, Sandra"
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- An epidemiological approach to characterise the human exposure pathways in a contaminated estuarine environmentPublication . Machado, Ausenda; Fernandes, Ana Paula; Paixão, Eleonora; Caeiro, Sandra; Dias, Carlos MatiasThis study's aim was to develop and implement an integrative epidemiologic cross-sectional study that allows identifying and characterising exposure pathways of populations living and working on the shores of a contaminated estuarine environment. Population residing in Carrasqueira, located on the Sado estuary with known contaminated areas was compared to another population on a noncontaminated estuary (Vila Nova de Mil Fontes - VNMF), considered a nonexposed population. Simple random samples of individuals were selected in each study population from the National Health Service Lists: 140 individuals were selected in Carrasqueira and 219 in VNMF. Participation rates were higher in the exposed group (62.5%, n=102 in Carrasqueira and 48.3%, n=100 individuals in VNMF). The same structured questionnaire was used in both populations, including questions on occupational activities, leisure activities, consumption of food (including fish and mollusks from the estuary) and use of water for human intake and agriculture. Results showed that a significantly higher proportion of Carrasqueira participants reported doing tasks in their job that promote direct (48.8% vs 1.2% in VNMF, p-value<0.001) or indirect (30% vs 11.9% in VNMF, p-value=0.004) contact with water from the estuary. Regarding seafood consumption, the exposed population of Carrasqueira had a higher frequency of consumption of cuttlefish (23.5% vs 9% in VNMF, p-value=0.007), sole (22.5% vs 4% in VNMF, p-value<0.001) and clams (18.6% vs 5.0 in VNMF, p-value=0.004). The comparative study design, with exposed and nonexposed populations living on the shores of two different estuaries allowed us to confirm the hypothesis of a higher risk of contamination from the contaminated estuarine environment. The study design and the selection of both populations were adequate for this type of epidemiologic study of potential routes of human contamination in a mixture of contaminated estuarine environment and can be used in other estuarine areas with similar environmental risk.
- An integrative assessment to determine the genotoxic hazard of estuarine sediments: combining cell and whole-organism responsesPublication . Costa, Pedro Manuel; Pinto, Miguel; Vicente, Ana M.; Gonçalves, Cátia; Rodrigo, Ana P.; Louro, Henriqueta; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoThe 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.
- Assessment of the Genotoxic Hazard of Estuarine Sediments Using an Integrative Approach With LacZ Plasmid‐Based Transgenic MicePublication . Pinto, Miguel; Sacadura, Joana; Costa, Pedro M.; Caeiro, Sandra; Louro, Henriqueta; Silva, Maria J.Under the influence of multiple anthropogenic pressures, from industrial to agricultural activities, estuaries have long been regarded as particularly sensitive ecosystems to contamination. The present study aimed at investigating the genotoxic potential of a contaminated sediment sample from an urban and industrial area of the Sado Estuary, by combining the analysis of multiple endpoints in the LacZ plasmid‐based transgenic mouse model exposed for 28 days to contaminated estuarine sediment extracts through drinking water. The DNA and chromosome damaging effects were monitored in peripheral blood at 7‐day intervals using the standard and enzyme‐modified Comet assay, as well as the micronucleus assays in peripheral blood cells. After euthanasia, DNA damage was analyzed in several mouse tissues, and LacZ mutant frequencies were determined in the liver. Livers were also surveyed for histopathological analysis. A time‐dependent increase in micronuclei frequency was seen at all tested doses, in spite of no induction of DNA damage in any organ or mutation induction in the liver of exposed mice. The liver from mice exposed to sediment extracts did not reveal major alterations besides evidence of inflammation. Overall, the integration of the endpoints analyzed in the mice is suggestive of potential chronic, rather than acute, adverse effects in vivo, and points to the need for further research in the resident human population in the area. This experimental design can be used to assess the genotoxicity of complex environmental mixtures, understand how they work, and reduce costs and resources while speeding up data collection and interpretation.
- Avaliação das vias potenciais de exposição humana num estuário contaminado: o caso do Estuário do SadoPublication . Silva, Susana Pereira; Machado, Ausenda; Paixão, Eleonora; Caeiro, Sandra; Dias, Carlos Matias
- Avaliação do potencial citotóxico e genotóxico de contaminantes de sedimentos do Estuário do Sado numa linha celular humanaPublication . Pinto, Miguel; Costa, Pedro Manuel; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria JoãoO 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.
- Avaliação do risco ambiental e para a saúde pública de um ambiente estuarino contaminadoPublication . Pinto, Miguel; Louro, Henriqueta; Caeiro, Sandra; Costa, Pedro; Costa, Maria Helena; Lavinha, João; Silva, Maria JoãoO 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.
- Can Estuary Sediment Contaminants Interfere with the DNA Repair Capacity of HEPG2 Cells?Publication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro Manuel; Caeiro, Sandra; SIlva, Maria JoãoEstuarine sediments tend to act as reservoirs of pollutants, many of which are acknowledged genotoxicants and potential carcinogens for humans. In addition, many of these environmental contaminants, particularly metals, have the potential to interfere with DNA repair mechanisms. Taking an impacted estuary as a case study (the Sado, SW Portugal), previous studies showed that human hepatoma cells (HepG2) exposed to extracts of sediments collected from two areas (urban/industrial and riverine/agricultural), both contaminated by distinct mixtures of organic and inorganic toxicants, revealed differential cytotoxic and genotoxic effects, consistent with contamination indices. In this context, the present study aimed at determining whether contaminants present in sediment extracts are able to interfere with the DNA repair mechanisms of HepG2 cells. Organic and inorganic contaminants were extracted (methanol:dichloromethane) from sediment samples collected in different sites of the Sado Estuary, either heavily impacted by an urban/industrial environment (site P) or by agriculture (sites E and A); a sediment collected in a potentially “clean” site was also included (site C). The repair capacity of HepG2 cells towards ethyl methanesulfonate (EMS, 5 - 40 mM, 1h) induced DNA lesions was assessed after cells recovery in the presence of non-genotoxic concentrations of each sediment extract, during 24h and 48h, using the comet assay. Negative and solvent controls were included. Preliminary results show that at 24h and 48h after exposure, 60% and 85% of EMS-induced DNA strand breakage, respectively, was spontaneously repaired by HepG2 cells. However, exposure to extracts P and A after EMS challenge, partially inhibited DNA repair given that, relatively to the spontaneous DNA repair level, 20 and 30%, of DNA damage remained unrepaired, after 24h whereas 30 and 40% remained unrepaired after 48h. Extract E slightly interfered with HepG2 DNA repair capacity (10% unrepaired damage), independently of the period of exposure. Extract C and solvent control did not interfere with DNA damage recovery, 24 and 48h after EMS exposure. Our results suggest that extracts P and A, which display the highest concentrations of PAHs and metals, respectively, produce a clear interference with the DNA repair capacity of HepG2 cells while less or no contaminated extracts (E and C, respectively) resulted in a low or no influence on DNA repair mechanisms. These results, together with the previous observations that extracts P and A were genotoxic, raise more concern on the potential hazard of estuarine contaminants on the health of exposed populations.
- Characterization of cytotoxic and genotoxic effects of contaminated sediments from the Sado Estuary and potential human health riskPublication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Costa, Maria Helena; Caeiro, Sandra; Lavinha, João; Silva, Maria JoãoThe 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).
- Comparação da prevalência de doenças não transmissíveis em populações expostas e não expostas a um ambiente estuarino contaminado – Projeto HERAPublication . Machado, Ausenda; Paixão, Eleonora; Silva, Susana Pereira; Caeiro, Sandra; Dias, Carlos Matias
- Cytotoxic and genotoxic assessment of potentially contaminated sediments from the Sado EstuaryPublication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoPrevious 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.
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