Genotoxic damages in zebrafish submitted to a polymetallic gradient displayed by the Lot River (France)

Genotoxic effects of a polymetallic pollution gradient displayed by the Lot River and one of its tributary have been assessed on zebrafish Danio rerio. Three methods were compared: RAPD-PCR, the comet assay, and 8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG) formation. The fishes were exposed for 14 days to waters collected from three stations: Joanis, a site polluted by cadmium (Cd) and zinc (Zn) (mean concentrations: 15 μg Cd/L and 550 μg Zn/L), Bouillac (mean concentrations: 0.55 μg Cd/L and 80 μg Zn/L), and Boisse-Penchot, a reference station (mean concentrations:<0.05 μg Cd/L and 7 μg Zn/L). The quantitative RAPD-PCR methodology proved to be sensitive enough to unmask metal genotoxicity after 3 and 7 days of exposure to Joanis water and after 14 days to Bouillac water, whereas the comet assay only detected DNA damages at the most contaminated station (Joanis). The 8-oxodG quantification was not sensitive enough to be used in zebrafish under these environmental conditions.