Browsing by Issue Date, starting with "2012-05-30"
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- 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).
- E. coli verotoxigénicosPublication . Saraiva, Margarida; Duarte, Sara LiaEscherichia coli produtora de Shiga toxina (STEC) é um agente patogénico para o Homem, responsável por infecções intestinais. Em casos mais graves pode evoluir para colite hemorrágica, síndrome hemolítico-urémico ou púrpura trombocitopénica. A ingestão de STEC a partir de alimentos contaminados é a principal fonte de infecção.
- Multi-residue analysis of 39 pesticides in surface waters of Ria de AveiroPublication . Vera, J.L.; Almeida, A.; Costa, J.M.; Domingues, V.F.; Delerue-Matos, C.; Mansilha, C.A multi-residue gas chromatography-mass spectrometry method was developed in order to evaluate the presence of 39 pesticides of different chemical families (organophosphorus, triazines, imidazole, organochlorine), as well as some of their transformation products, in surface water samples from Ria de Aveiro. Ria de Aveiro is an estuarine coastal lagoon, located in the northern west region of Portugal, which receives inputs from agriculture, urban and industrial activities. The analytical method was developed and validated according international guidelines and showed good linearity, with correlation coefficients higher than 0.9949 for all compounds, adequate precision and accuracy, and high sensitivity. Pesticides were chosen from the priority pollutants list of the Directive 2008/105/EC of the European Parliament and of the Council (on environmental quality standards in the field of water policy), or were selected due their common use in agricultural practices. Some of these 39 pesticides are, or are suspected to be, endocrine disruptor compounds (EDCs), being capable of altering the endocrine system of wildlife and humans, causing form malfunction and ultimately health problems. Even those pesticides which are not EDCs, are known to be awfully toxic and have a recognised impact in human health. The aquatic environment is particularly susceptible to pollution due to intentional and accidental release of chemicals to water [3]. Pesticide contamination of surface water is a national issue as it is often used as drinking water. This concern is especially important in rural agricultural areas where population uses small private water supplies, regularly without any laboratory surveillance. The study was performed in seven sampling points and the results showed a considerable concern pesticide contamination of all samples.
- Brassica oleracea L. Var. costata DC and Pieris brassicae L. aqueous extracts reduce methyl methanesulfonate-induced DNA damage in V79 hamster lung fibroblastsPublication . Sousa, Carla; Fernandes, Fátima; Valentão, Patrícia; Rodrigues, António Sebastião; Coelho, Marta; Teixeira, João Paulo; Silva, Susana; Ferreres, Federico; Guedes de Pinho, Paula; Andrade, Paula B.Brassica oleracea L. var. costata DC leaves and Pieris brassicae L. larvae aqueous extracts were assayed for their potential to prevent/induce DNA damage. None of them was mutagenic at the tested concentrations in the Ames test reversion assay using Salmonella His+ TA98 strains, with and without metabolic activation. In the hypoxanthine-guanine phosphoribosyltransferase mutation assay using mammalian V79 fibroblast cell line, extracts at 500 μg/mL neither induced mutations nor protected against the mutagenicity caused by methyl methanesulfonate (MMS). In the comet assay, none of the extracts revealed to be genotoxic by itself, and both afforded protection, more pronounced for larvae extracts, against MMS-induced genotoxicity. As genotoxic/antigenotoxic effects of Brassica vegetables are commonly attributed to isothiocyanates, the extracts were screened for these compounds by headspace–solid-phase microextraction/gas chromatography–mass spectrometry. No sulfur compound was detected. These findings demonstrate that both extracts could be useful against damage caused by genotoxic compounds, the larvae extract being the most promising.