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- DNA damage and lipid peroxidation vs. protection responses in the gill of Dicentrarchus labrax L. from a contaminated coastal lagoon (Ria de Aveiro, Portugal)Publication . Ahmad, I.; Maria, Vera L.; Oliveira, M.; Serafim, Angela; Bebianno, Maria João; Pacheco, M.; Santos, M.A.The present research work aimed to investigate the damage vs. protection responses in gill of European sea bass (Dicentrarchus labrax) captured at a polluted coastal lagoon, Ria de Aveiro (Portugal), as a tool to evaluate the human impacts on environmental health. Damage was assessed as DNA strand breakage and lipid peroxidation (LPO) whereas protection was evaluated by measuring catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (GSHt), thiols and metallothioneins (MT). Fish were caught at five locations: Gafanha (GAF), Rio Novo do Príncipe (RIO), Laranjo (LAR) and Vagos (VAG) presenting each a different recognized source of contamination, and Torreira (TOR), assumed as reference site. Among the surveyed sites, gill damage was observed only at GAF, as measured by DNA integrity loss and LPO increase. An overall induction in enzymatic antioxidant protection was perceptible in fish from GAF and VAG, expressed as higher GPX, GR and GST activities. In addition, LAR fish showed elevated GST and CAT activities. Thiols content was higher in all study sites irrespective to the pollution spectrum, whereas GSHt increase was only observed at GAF and VAG. The highest MT level was detected in fish from VAG and the lowest level from RIO suggesting a low contamination degree on this particular site. Globally, the results expressed site-specific response patterns, signalling two critical areas - GAF and VAG. Additionally, a joint analysis (damage vs. protection) allowed the following ordering of surveyed sites according to the contamination degree and risk to fish health; GAF>VAG>LAR>RIO>TOR. D. labrax gill responses demonstrated their efficacy as early warning signals of the contaminants presence. Moreover, the adopted approach, considering simultaneously protection responses and damaging effects, also revealed its usefulness on the pollution extent assessment.
- 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.
- 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.