The Long-Term Exposure to Discharges of Sabal Drain Induces Genotoxic Effects on Oreochromis niloticus.

To study the genotoxic impacts of Sabal discharges, three sites around Sabal drain were selected and compared to a reference site (site1). Site2 was at the southern part of the main canal, site3 was at the main canal outlet, and site4 at the northern part of the main canal. Compared to the reference fish, the recorded micronuclei and other nuclear anomalies showed marked (p < 0.05) increases with different frequencies in the studied sites. The induction of nuclear deformations was as following site3 > site4 > site2 > site1. The analysis of comet assay data showed that the DNA damage (based on the percentage of tail DNA) was significantly increased and the levels of damage were associated with the distance from the main discharge point. Moreover, DNA damages showed variable percentages among the studied tissues. The gills and liver tissues collected from site3 showed the highest DNA damage compared with low muscular DNA damage.