Genotoxic action of naphthenic acids on the fish macrophage cell line, RTS11

Abstract

Naphthenic acids (NAs) are chemical constituents found in oil sands process-affected waters (OSPW) that are distinctly toxic to biota. They comprise an ill-defined mixture of carboxylic acids implicated in endocrine disruption, acute toxicity, immunotoxicity, tissue malformation and embryotoxicity in several fish species, in addition to being cytotoxic. Recent evidence indicates a possible genotoxic effect and the present study evaluated the genotoxic potential of NAs using the 'comet' assay and the rainbow trout spleen cell line, RTS11. The results provided a genotoxic value (in arbitrary units) two times higher for the NA concentration at 10 μg/mL (≈ 105) relative to the NA at 1 μg/mL (≈ 45). NAs at 10 μg/mL gave a damage index of 45.86% compared to the damage observed with a positive control-hydrogen peroxide, which was 90.66% (evaluated at 100 μM). The data obtained suggest a genotoxic potential for NAs at doses that could occur naturally in OSPW.