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- Hepatic metallothionein concentrations in the golden grey mullet (Liza aurata): relationship with environmental metal concentrations in a metal-contaminated coastal system in PortugalPublication . Oliveira, M.; Ahmad, I.; Maria, Vera L.; Serafim, A.; Bebianno, Maria João; Pacheco, M.; Santos, M.A.This field survey was designed to assess the environmental metal contamination status of Ria de Aveiro (Portugal). To achieve that goal, the concentrations of Cd, Hg, Cu and Zn in the sediments and water were assessed and Liza aurata hepatic metallothionein (MT) determined. The relationships between MT and environmental metal concentrations and hydrological factors were examined. Results revealed a wide distribution of metals both in water and sediments throughout the lagoon, mainly at Rio Novo do Principe (RIO) and Laranjo (LAR), at concentrations that may affect biota. MT concentrations were higher at the sites with high metal content (RIO and LAR). A significant positive correlation was found between MT and Cd in the sediments as well as with MT and Hg and Cu in the water. Moreover, a negative correlation between MT and salinity was found. Thus, the current data support MT use as a biomarker of metal exposure emphasizing the importance of hydrological parameters in its concentrations. Results suggest the continued monitoring of this lagoon system.
- Contamination assessment of a coastal lagoon (Ria de Aveiro, Portugal) using defence and damage biochemical indicators in gill of Liza aurata – An integrated biomarker approachPublication . Oliveira, M.; Maria, Vera L.; Ahmad, I.; Serafim, Angela; Bebianno, Maria João; Pacheco, M.; Santos, M. A.Fish gill importance in toxicants uptake, bioconcentration and excretion allied to meagre knowledge on branchial damage/protection responses substantiate this study. Five critical sites in Ria de Aveiro (Portugal) were assessed in comparison with a reference site (Torreira), focusing on Liza aurata gill antioxidant defences versus damage (oxidative and genetic). Only in Barra fish displayed damage (lipid peroxidation) though no differences were found in antioxidants. In all other sites, except Rio, antioxidant alterations were found. Thus, fish from Gafanha, Laranjo and Vagos showed higher total glutathione, glutathione peroxidase and catalase. Higher glutathione reductase and glutathione S-transferase activity was also found in the first and the last sites, respectively. In Laranjo, metallothionein levels were higher though lower in Gafanha and Vagos. In general, damage was not accompanied by defences weakening confirming that predicting damage based on antioxidants depletion is not straightforward. The integrated biomarker response index ranked sites as: Gafanha>Barra>Laranjo>Vagos>Rio>Torreira.
- Evaluation of oxidative DNA lesions in plasma and nuclear abnormalities in erythrocytes of wild fish (Liza aurata) as an integrated approach to genotoxicity assessmentPublication . Oliveira, M.; Ahmad, I.; Maria, Vera L.; Ferreira, C. S. S.; Serafim, A.; Bebianno, Maria João; Pacheco, M.; Santos, M. A.Genetic lesions (8-hydroxy-2'-deoxyguanosine (8-OHdG) and erythrocytic nuclear abnormalities (ENA) were seasonally quantified in the blood of Liza aurata caught at Ria de Aveiro (Portugal), a multi-contaminated aquatic system. Thus, five critical sites were assessed and compared with a reference site (Torreira). Oxidative DNA damage was found in Gafanha (harbour-water area), Laranjo (metal-contaminated) and Vagos (contaminated with PAHs) in the spring; Rio Novo do Principe (near a former paper-mill effluent) in the autumn; Rio Novo do Principe and Vagos in the winter. ENA were higher than Torreira at VAG (spring and winter). Torreira did not display seasonal variation neither in terms of 8-OHdG or total ENA. A positive correlation between 8-OHdG and ENA was found, suggesting oxidative stress as a mechanism involved in the formation of ENA. This study clearly demonstrates the presence of DNA-damaging substances in Ria de Aveiro and recommends the use of 8-OHdG and ENA as biomarkers of environmental contamination.