Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, PortugalPublication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Peixoto, Francisco P.; Salgado, Maria AntóniaHeavy metal (Cu and Zn) concentrations in liver, gills, and muscle of leaping grey mullet, Liza saliens, from the Portuguese Esmoriz–Paramos coastal lagoon were measured to evaluate their bioaccumulation as a function of sediment contamination. The highest metal concentrations were observed in the liver (254mg Cu kg 1) and gills (114 mgZn kg 1). Bioaccumulation factors (BAFs) were found to follow the order: Cu-liver4Cu-gills4Cu-muscle and Zn-gills4Zn-liver4Zn-muscle. The highest BAFs were observed in the organs mainly implicated in metal metabolism and a significant positive relationship was found between BAFs and fish age. These results suggest the loss of homeostatic capacity of L. saliens under chronic metal exposure leading to bioaccumulation. Furthermore, Cu-liver and Zngills accumulation can be good environmental indicators of metal stress in L. saliens
- Monitoring pollution in Esmoriz–Paramos lagoon, Portugal: liver histological and biochemical effects in Liza saliensPublication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Rocha, E.; Salgado, Maria AntóniaThe Esmoriz–Paramos lagoon is one important ecosystem located in the Northwest coast of Portugal. This study is concerned with the assessment of pollution of the lagoon contributed by urban, industrial and agricultural activities. The parameters selected for this aim were the occurrence of hepatic histological alterations and plasma blood biochemistry in Liza saliens, the dominant fish in this lagoon. Blood parameters were compared between mullets collected from the lagoon and from the sea and included plasma enzyme activities (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP)), glucose (GLU) and total protein (TP).Apositive relationship between hepatocyte vacuolization index and hepatosomatic index was found, suggesting that lipid accumulation could have contributed to the increase of liver weight. The hepatic alterations recorded included general diagnostic categories and additionally large areas of heterogeneous parenchyma, composed of hepatocytes with different spectrum of vacuolization. Liver histopathological evaluation revealed a sample prevalence of 34% for heterogeneous parenchyma, 31% for foci of necrosis and 9% for non-neoplastic lesions. No neoplastic lesions were found. Livers with heterogeneous parenchyma showed higher Cu and Zn content than livers without this category of lesion, suggesting that metals accumulated could trigger this hepatic alteration. AST was higher in mullets from the lagoon than in mullets from the sea, but no differences in ALP and ALT were found, suggesting a change in protein metabolism as an adaptive response to metals exposure. The higher glucose and protein contents observed in fish caught in the lagoon are consistent with a stress response and the measurement of plasma AST activity could be a sensitive indicator of lagoon fish stress. In conclusion, Esmoriz–Paramos lagoon biomonitorization, using indicator species will proceed to assess the impact of the restoration program under development by the Portuguese government.
- Heavy metals in water, sediment and tissues of Liza saliens from Esmoriz-Paramos lagoon, Portugal.Publication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Cabral, David; Salgado, Maria AntóniaEsmoriz–Paramos lagoon is an ecosystem of great ecological importance that is located on the northwest coast of Portugal and has been degraded as a result of industrial and anthropogenic activities. Concentrations of heavy metals (Cr, Cu, Pb and Zn) were measured in water, sediment and in tissues (liver and muscle) of Liza saliens, which is the dominant fish from the lagoon. Comparisons between metal concentrations in water and sediments were made with those in tissues of fish caught at the lagoon. Metals in water were quantified predominantly bound to particulate and equalled or exceeded the limit of chronic reference values. Metal concentrations in sediments varied among sampled sites. The relative order of concentrations was “Zn>Cu∼Pb>Cr” the same pattern observed for metals in water. Metals in fish tissues showed higher concentrations in liver (262 mg Cu·Kg−1 and 89 mg Zn·Kg−1) than in muscle (<3 mg Cu·Kg−1 and 26 mg Zn·Kg−1), while Pb and Cr were not detected. These results suggest that Cu and Zn are the metals of major concern in the lagoon. Mullet detritivorous feeding habits, bioaccumulation pattern and the high sediment metals concentrations relative to the water suggest that sediments can be the most important source of contamination in this ecosystem. The positive relationship found between Cu in liver and fish length demonstrates that time of exposure is a crucial factor in bioaccumulation. Condition indices (K and HSI) in mullets from the lagoon were higher compared to mullets from sea, suggesting abnormal condition in the lagoon population. We conclude that metals chronic exposure in the lagoon can impose considerable fish stress. The results also show that the lagoon is an area of environmental concern.