In vitro mucus transportability, cytogenotoxicity, and hematological changes as non-destructive physiological biomarkers in fish chronically exposed to metals.

The biomonitoring of fish using biomarkers represents a useful tool for the assessment of aquatic pollution. This study evaluated the sublethal toxic effects of aquatic pollution on fish collected from a site contaminated by metals. Water and fish (Oreochromis niloticus) samples were collected from a pond in the Parque Ecológico do Tietê (PET) that lies along the Tietê River (São Paulo, Brazil), and from a control site (an experimental fish farm). The metal content of the water was evaluated, and fish were used to examine the properties of gill mucus and blood. The PET fish were evaluated for alterations in the in vitro transportability of mucus and changes in blood properties (e.g., cell volume, hemoglobin concentration, red blood cells, and white blood cell count). The results of the water analyzes indicated metal levels above the legal standards for Fe (0.71 mg/L), Ni (0.06 mg/L), Mn (0.11 mg/L), and Pb (0.48 mg/L). Compared to the controls, the hematologic parameter analyzes of PET fish revealed significantly higher numbers of erythrocytes (RBC), leukocytes (WBC), lymphocytes, erythroblasts, and Mean Corpuscular Volume (MCV); however, the hemoglobin content and Mean Corpuscular Hemoglobin Concentration (MCHC) values were significantly lower. The frequencies of nuclear abnormalities and micronuclei were significantly higher and the mucociliary transport was significantly lower in PET fish than in the controls. These results suggest that fish from the contaminated site exhibit a series of physiological responses, which probably indicate health disturbances. Furthermore, the results suggest that blood and mucus are promising, non-destructive targets for use in the monitoring of pollution.

Cytogenotoxicity biomarkers in fat snook Centropomus parallelus from Cananéia and São Vicente estuaries, SP, Brazil.

The aquatic environment receives many contaminants that can induce damages at the molecular, biochemical, cellular and physiological levels. Centropomus parallelus, an important food resource for local populations, is a predator fish that feeds on small fishes and benthic invertebrates, thus being vulnerable to the bioconcentration and biomagnification processes. This study aimed to evaluate cytogenotoxic responses in erythrocytes from C. parallelus juveniles collected in the Cananéia and São Vicente estuaries, both in winter and in summer. After anesthesia, blood samples were collected by caudal puncture. Blood smears were prepared on glass slides and stained with May-Grünwald-Giemsa dye. Two thousand cells were analyzed per slide (1000x), and nuclear abnormalities (NA) and micronuclei (MN) were scored. The São Vicente sample showed MN and NA frequencies (%/1000 cells) of 0.325 and 3.575, in winter, and of 0.125 and 2.935 in summer respectively; the Cananéia sample showed frequencies of 0.0325 and 0.03, in winter, and of 0.065 and 0.355 in summer, respectively. The rates found in São Vicente were significantly higher than those found in Cananéia, evidencing that the levels of pollution in that estuary were high enough to induce genetic damages.

Cytogenotoxicity biomarkers in fat snook Centropomus parallelus from Cananéia and São Vicente estuaries, SP, Brazil

The aquatic environment receives many contaminants that can induce damages at the molecular, biochemical, cellular and physiological levels. Centropomus parallelus, an important food resource for local populations, is a predator fish that feeds on small fishes and benthic invertebrates, thus being vulnerable to the bioconcentration and biomagnification processes. This study aimed to evaluate cytogenotoxic responses in erythrocytes from C. parallelus juveniles collected in the Cananéia and São Vicente estuaries, both in winter and in summer. After anesthesia, blood samples were collected by caudal puncture. Blood smears were prepared on glass slides and stained with May-Grünwald-Giemsa dye. Two thousand cells were analyzed per slide (1000x), and nuclear abnormalities (NA) and micronuclei (MN) were scored. The São Vicente sample showed MN and NA frequencies (%/1000 cells) of 0.325 and 3.575, in winter, and of 0.125 and 2.935 in summer respectively; the Cananéia sample showed frequencies of 0.0325 and 0.03, in winter, and of 0.065 and 0.355 in summer, respectively. The rates found in São Vicente were significantly higher than those found in Cananéia, evidencing that the levels of pollution in that estuary were high enough to induce genetic damages.