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Exploring the potential interference of estuarine sediment contaminants with the DNA repair capacity of human hepatoma cells

Publication . Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Caeiro, Sandra; Silva, Maria

Estuaries may be reservoirs of a wide variety of pollutants, including mutagenic and carcinogenic substances that may impact on the ecosystem and human health. A previous study showed that exposure of human hepatoma (HepG2) cells to extracts from sediment samples collected in two areas (urban/industrial and riverine/agricultural) of an impacted estuary (Sado, Portugal), produced differential cytotoxic and genotoxic effects. Those effects were found to be consistent with levels and nature of sediment contamination. The present study aimed at evaluating whether the mixtures of contaminants contained in those extracts were able to modulate DNA repair capacity of HepG2 cells. The residual level of DNA damage was measured by the comet assay in cells exposed for 24 or 48 h to different extracts,after a short preexposure to a challenging concentration range of ethyl methanesulfonate(EMS), as a model alkylating agent. The results suggested that the mixture of contaminants present in the tested samples, besides a potential direct effect on the DNA molecule, may also interfere with DNA repair mechanisms in HepG2 cells, thus impairing their ability to deal with genotoxic stress and, possibly, facilitating accumulation of mutations. Humans are environmentally/occupationally exposed to mixtures rather than to single chemicals. Thus, the observation that estuarine contaminants induce direct and indirect DNA strand breakage in human cells, the latter through the impairment of DNA repair, raises additional concerns regarding potential hazards from exposure and the need to further explore these endpoints in the context of environmental risk assessment.

2015-05-12Journal article

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Characterization of arsenic and selenium species in Portuguese diet as a contribution to selenium protective mechanism against arsenic toxicity

Publication . Gueifão, Sandra; Delgado, Inês; Ventura, Marta; Coelho, Inês; Castanheira, Isabel

Background and objective(s): Selenium is an essential trace element for human health. Through selenoproteins, it participates in various biological processes such as antioxidant defence, thyroid hormone production and immune responses. The role of Se in the prevention of As – induced toxicity has been documented in several studies. Se-dependent sequestration of As is suggested as a primary mechanism of interaction between Se and As toxic species. To understand the mechanisms involved in the Se/As interactions it is necessary to characterize their presence in foods as principal source of exposure. The aim of this work was to evaluate Se Methionine (SeMet), Selenite (Se (IV)) and Selenate (Se (VI)) and Arsenite (As(III)), Arsenate (As(V)), Dimethylarsinic acid (DMA) and Arsenobetaine (AsB) in fresh and cooked foods representative of the Portuguese Diet. Materials and methods: Speciation analysis was carried out by High Performance Liquid Chromatography (HPLC) coupled to Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Before analysis, samples were extracted using specific extraction procedures for As and Se. Results: More than 90% of the As present in fish samples was in the form of AsB while in rice samples results showed that 80% of the As was present as inorganic forms and 20% as DMA. SeMet was the major Se species in milk and fish samples accounting for 85-90 % of the total Se content. In cabbage Se (IV), Se (VI) and (SeMet) were found. Discussion and conclusion(s): The results showed the suitability of the analytical procedures to achieve an accurate determination of As and Se species in these complex matrices.

2017-05-08Conference object

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Environmental exposure to toxicants mixtures from a multi-purpose estuary: perspectives for a biomonitoring study in Portugal

Publication . Silva, Maria João; Pinto, Miguel; Costa, Pedro M.; Louro, Henriqueta; Castanheira, Isabel; Machado, Ausenda; Dias, Carlos; Fernandes, Ana Paula; Martinho, AP; Costa, MH; Caeiro, Sandra; Lavinha, Joao

This work was focused on a multi-purpose estuarine environment (river Sado estuary, SW Portugal) around which a number of activities (e.g., fishing, farming, heavy industry, tourism and recreational activities) coexist with urban centres with a total of about 200 000 inhabitants. Based on previous knowledge of the hazardous chemicals within the ecosystem and their potential toxicity to benthic species, this project intended to evaluate the impact of estuarine contaminants on the human and ecosystem health. An integrative methodology based on epidemiological, analytical and biological data and comprising several lines of evidence, namely, human contamination pathways, human health effects, consumption of local produce, estuarine sediments, wells and soils contamination, effects on commercial benthic organisms, and genotoxic potential of sediments, was used. The epidemiological survey confirmed the occurrence of direct and indirect (through food chain) exposure of the local population to estuarine contaminants. Furthermore, the complex mixture of contaminants (e.g., metals, pesticides, polycyclic aromatic hydrocarbons) trapped in the estuary sediments was toxic to human liver cells exposed in vitro, causing cell death, oxidative stress and genotoxic effects that might constitute a risk factor for the development of chronic-degenerative diseases, on the long term. Finally, the integration of data from several endpoints indicated that the estuary is moderately impacted by toxicants that affect also the aquatic biota. Nevertheless, the human health risk can only be correctly assessed through a biomonitoring study including the quantification of contaminants (or metabolites) in biological fluids as well as biomarkers of early biological effects (e.g., biochemical, genetic and omics-based endpoints) and genetic susceptibility in the target population. Data should be supported by a detailed survey to assess the impact of the contaminated seafood and local farm products consumption on human health and, particularly, on metabolic diseases or cancer development.

2016-04-17Conference object

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HERA - Environmental Risk Assessment of a contaminated estuarine environment: a case study

Publication . Martinho, Ana Paula; Rodrigo, Ana; Vicente, Ana; Machado, Ausenda; Dias, Carlos Matias; Guiomar, Carla Sofia; Gonçalves, Cátia; Paixão, Eleonora; Santos, Fernanda; Louro, Henriqueta; Pinhal, Hermínia; Mateus, Inês; Coelho, Inês; Lopes, Inês; Castanheira, Isabel; Antunes, Joana; Sacadura, Joana; Lavinha, João; Toro, Joaquim; Lobo, Jorge; Nunes, Luís; Quintas, Maria do Carmo; Costa, Maria Helena; Silva, Maria João; Saraiva, Marina; Diniz, Mário; Martins, Marta; Pinto, Miguel; Fernandes, Paula Vaz; Costa, Pedro M.; Caeiro, Sandra; Gueifão, Sandra; carreira, Sara; Silva, Susana Pereira; Neuparth, Teresa

Sado River estuary is located in the west coast of Portugal. Previous environmental studies identified industrial contamination, non-point anthropogenic sources and contamination coming from the river, all promoting accumulation of polluted sediments with known impacts on the ecological system. Surrounding human populations have intense economic fishery activities. Together with agriculture, estuary fishing products are available to local residents. Food usage previously characterized through ethnographic studies suggests exposure to estuarine products, farming products, and water in daily activities, as potential routes of contamination. It is well established that long term exposure to heavy metals are associated with renal and neurological diseases, most heavy metals are classified as carcinogenic and teratogenic.

2013-11Report

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Estado de saúde da população da Carrasqueira

Publication . Dias, Carlos Matias; Paixão, Eleonora; Silva, Susana Pereira; Machado, Ausenda

Neste seminário pretende-se divulgar os principais resultados e conclusões do projeto de investigação HERA. O objetivo deste projeto foi avaliar o risco ambiental, incluindo o risco ecológico e para a saúde humana, associado ao ambiente sedimentar estuarino do estuário do Sado, em particular devido ao consumo de espécies estuarinas com valor comercial e à proximidade ao estuário. Foi utilizada como população-alvo uma pequena população de pescadores que habitam a vila da Carrasqueira no Estuário do Sado a qual foi comparada com uma população controle localizada no mesmo distrito, mas fora da bacia do estuá-rio: Vila Nova de Mil Fontes.

2013-10Lecture

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