No abstract

The environment quality of an industrial district on the river Pará, Amazon estuary, Brazil, based on the assessment of histological alterations and on the determination of catalase activity of the hepatic tissue of two fish species, Plagioscion squamossissimus and Lithodoras dorsalis, is provided. Histopathological changes were evaluated semi-quantitatively and qualitatively. Mean Assessment Values (MAV) and Histological Alteration Index (HAI) of organ lesions were calculated for each zone under analysis, with different impact levels: Zone 1 (industrial district, with high contamination risk); Zone 2 (medium risk) and Zone 3 (minimum risk). Strong positive catalase activity and histopathological changes were reported in Zone 1. None of the specimens of either species captured in Zones 1 and 2 was healthy, whereas more than 60% of the specimens from Zone 3 presented healthy hepatic tissue. The principal alterations observed in the tissue of the two species included an increase in the number of Melanomacrophagous centers, fatty degeneration, inflammation, congestion, hepatitis and focal necrosis. The carnivorous P. squamosissimus presented higher levels of alteration than the herbivorous L. dorsalis. Results showed that local anthropogenic impacts were affecting the health of the two fish species under analysis.

No abstract

No abstract

No abstract

No abstract

No abstract

The present field study aimed to assess the water quality of the Itacaiúnas River, located at the eastern part of the Brazilian Amazon, using water's physicochemical parameters, ecological risk assessment in sediments, biomarkers and metal bioaccumulation in piranhas at two points: upstream (P1) and downstream (P2), and the type of season (Dry and Rainy). We revealed a significant difference between the points and the seasons. Concerning, the concentration of metals (Cd, Cu, Zn, Cr, and Hg) in sediment and water, we reported significant concentrations of Cd and Cu especially on P2 at dry season. The fish gills collected in P2 showed various types of damages (moderate and severe), furthermore, the Degree of Tissue Change (DTC) reported a significant difference between points, highlighting the dreadful condition in animals' health originated from this point. In terms of the biotransformation enzyme, the GST activity was higher in fishes from P2 in both seasons. The obtained results showed clear signs of stress in fish from the downstream point. Linear correlation analysis exhibited that the biomarkers' response could be linked to the detected metals bioaccumulation. This field investigation provides baseline data on pollution status in this region and the results showed that although the overall potential ecological risks of the metals were considered low at our sampling sites including cadmium, however, Cd posed a noteworthy monomial potential ecological risk factor. Strong evidence of correlation was obtained between Cd in the environment with the gills' damage in fishes from P2. The results also indicated that S. rhombeus could be useful for biomonitoring species for assessing metal contamination.