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- Avaliação da contaminação por hidrocarbonetos de petróleo em mexilhões Mytilus galloprovincialis da costa sul de Portugal. O sistema MFO como biomarcador de contaminaçãoPublication . Lopes, Belisandra Maria Martins; Bebianno, Maria João da Anunciação FrancoO crescimento da actividade industrial verificada durante o século passado resultou num rápido aumento da entrada de uma grande variedade de contaminantes orgânicos potencialmente tóxicos no ambiente estuarino e zonas costeiras, tais como os hidrocarbonetos do petróleo. A costa Portuguesa é atravessada por alguns dos principais e mais movimentados Esquemas de Separação de Tráfego (ESTs) de navios de/para o Mediterrâneo, Norte da Europa, África e América, apresentando um risco considerável de poluição marinha. Nesta dissertação, o impacto de hidrocarbonetos do petróleo (fracção alifática e aromática) foi avaliada pelo uso integrado de análises químicas e de respostas bioquímicas específicas, como o citocromo P450 (componente principal do sistema MFO) em mexilhões Mytilus galloprovincialis recolhidos em 8 locais da costa Sul de Portugal. A concentração dos hidrocarbonetos alifáticos (HAs) e aromáticos policíclicos (PAHs) avaliada nos mexilhões permite discriminar entre locais com contaminação ambiental elevada a muito elevada (Vilamoura-VM e Olhão-OL) e locais onde a contaminação ambiental apresenta valores considerados de base (Faro-FR e Tavira-TV). A variação sazonal revela concentrações mais elevadas no Outono e Inverno, relativamente à Primavera e ao Verão. Os n-alcanos, isoprenoides e PAHs individuais indicam contaminações petrogénicas e pirolíticas, com origem em petróleo/óleo não queimado, combustão incompleta de combustíveis fósseis e combustão de biomassa. A acumulação de hidrocarbonetos nos tecidos dos mexilhões decresce ao longo do tempo, indicando uma redução da influência antropogénica e uma melhoria geral das condições ambientais. A variação sazonal e espacial da concentração de citocromo P450 (CYP450) apresenta o mesmo padrão que o dos hidrocarbonetos, existindo uma relação significativa entre si. Os mexilhões foram transplantados de um local limpo (TV) para um local contaminado (VM), e vice-versa. Nos ensaios de vi transplante os organismos acumulam hidrocarbonetos de modo diferente, adquirindo os mexilhões características do local para onde foram transplantados. A acumulação de hidrocarbonetos está directamente relacionada com a concentração de CYP450, enfatizando o metabolismo deste tipo de compostos pelo mexilhão M. galloprovincialis.
- Comparative petroleum hydrocarbons levels and biochemical responses in mussels from hydrothermal vents (Bathymodiolus azoricus) and coastal environments (Mytilus galloprovincialis)Publication . Serafim, Angela; Lopes, Belisandra; Company, Rui; Ferreira, A. M.; Bebianno, Maria JoãoAliphatic hydrocarbons and PAHs in the whole soft tissues of Bathymodiolus azoricus from three Mid-Atlantic Ridge hydrothermal vents (Menez-Gwen, Lucky Strike and Rainbow), and Mytilus galloprovincialis from three contaminated coastal sites in South Portugal were analysed, and its effects on the digestive gland microsomes mixed-function oxygenase system (MFO) were assessed. Aliphatic hydrocarbons levels were present in the same magnitude in both coastal and hydrothermal environments, while the UCM (unresolved complex mixture) for coastal mussels were higher than in vent mussels. In general, significantly higher PAHs concentrations were found in coastal mussels, compared to B. azoricus where low molecular weight PAHs (2-3 rings) represented the majority of PAHs contrarily to what was observed in M. galloprovincialis. The MFO components were present in both mussel species, and were detected in vent mussels for the first time. However this system seems to have different roles in species from these contrasting environments. In coastal mussels MFO responded to hydrocarbon contamination while response in hydrothermal organisms appeared to be related mainly to endogenous factors.
- A multibiomarker approach in Mytilus galloprovincialis to assess environmental qualityPublication . Cravo, Alexandra; Lopes, Belisandra; Serafim, M.A.; Company, Rui; Barreira, Luísa; Gomes, Tânia; Bebianno, Maria JoãoA multibiomarker approach was carried out for the first time in the South Portuguese Coast using Mytilus galloprovincialis, to assess environmental quality, establish if there are adverse biological responses associated to different sources of anthropogenic contamination and to determine spatial and seasonal trends. For this purpose the battery of biomarkers selected was: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx total and Se dependent), Cytochrome P450 component system, Glutathione-S-transferase (GST) and acetylcholinesterase (AChE), metallothionein (MT) and lead-delta-aminolevulinic acid dehydratase (ALAD), lipid peroxidation (LPO) and Condition Index (CI) along with the determination of PAHs and metals (Cd, Cu, Ni, Pb and Zn). Results show that despite the levels of both organic and metallic contaminants in these eight spots in the South Coast of Portugal not being particularly high compared with other contaminated/polluted sites worldwide, the selected battery of biomarkers responded efficiently to the environmental changes and allowed an environmental assessment between seasons and sites. Different spatial and seasonal responses were evident along the South Coast of Portugal, meaning that the contamination is not homogeneous. This does not only reflect different competition, origin and intensity of contamination, but also different environmental conditions (e.g. temperature, salinity). Along the South Portuguese Coast site 8 was the most contaminated, while site 2 was considered the least contaminated. Despite environmental factors possibly causing difficulties in the general interpretation of biomarker data, those that better responded to environmental contamination were CYP450, SOD-mit and T-GPx for the summation SigmaPAHs, MT (digestive gland) for metals (especially Cu), ALAD for Pb and LPO for both organic and metallic contamination. These biomarkers were also positively correlated with temperature in summer, revealing this as a more stressful/critical season. In future environmental contamination assessments there is no need to analyse the components b5, P418, NADH and NADPH of phase I MFO system, and MT in the gills, since their responses are not evident.
- Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: A freshwater bivalve studyPublication . Company, Rui; Serafim, Angela; Lopes, Belisandra; Cravo, A.; Shepherd, T. J.; Pearson, G.; Bebianno, Maria João; Cravo, AlexandraLead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, delta-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.