Detection of micronuclei and other nuclear abnormalities in Oreochromis niloticus exposed to potassium dichromate.

The objective of this paper was to analyze the micronuclei (MNs) and other nuclear abnormalities (NAs) frequencies in peripheral blood of Nile tilapia (Oreochromis niloticus) treated with potassium dichromate via contaminated water. Blood samples were collected from caudal vessels after potassium dichromate 12 mg.L expositions for 24 and 48 hours. The typical micronuclei were not found in control group. 1 In the exposed groups the frequencies were 1.0 ± 1.15 at 24h and 2.43 ± 0.98 at 48h. The nuclear morphological alterations frequencies in control, 24h and 48h were 4.29 ± 4.50, 5.86 ± 3.02 and 11.0 ± 3.74, respectively. The parametric ANOVA showed a very significant difference (p < 0.01) in MNs frequencies between control and 48h groups; also there was significant difference (p < 0.05) between the two exposition times. In the NAs, there was significant difference only between control and exposed for 48h groups (p < 0.05). Results confirm the potentially adverse effects of potassium dichromate. The demonstrated sensitivity to this ion shows that Oreochromis niloticus can be used to monitor for the acute effects of pollutants on the basis of hexavalent chromium in freshwater ecosystem.