Stereoselective induction by 2,2ʹ,3,4ʹ,6-pentachlorobiphenyl in adult zebrafish (Danio rerio): Implication of chirality in oxidative stress and bioaccumulation

This study aimed to investigate the oxidative stress process and bioaccumulation the racemic/(−)-/(+)- 2,2ʹ,3,4ʹ,6-pentachlorobiphenyl were administered to adult zebrafish (Danio rerio) after prolonged exposure of 56-days uptake and 49-days depuration experiments. Stereoselective accumulation was observed in adult samples after racemic exposure as revealed by decreased enantiomer fractions. The two enantiomers of PCB91 accumulated at different rates with logBCFk values close to 3.7, suggesting that they were highly hazardous and persistent pollutants. Exposure to racemic/(−)-/(+)- PCB91 stereoselectively induced oxidative stress owing to changes in reactive oxygen species, malondialdehyde contents, antioxidant enzyme activities and gene expressions in brain and liver tissues. In addition, the stereoselective relationship between bioconcentration and oxidative stress were also presented in this study. Our findings might be helpful for elucidating the environmental risk of the two enantiomers of PCB91 that induce toxicity in aquatic organisms. •Stereoselective accumulation was observed in zebrafish after racemic PCB91 exposure with logBCFk close to 3.7.•Exposure to chiral PCB91 stereoselectively induced oxidative stress in adult zebrafish.•Dose-dependent changes in oxidative stress occurred during racemic/(−)-/(+)- PCB91 exposure.•ROS as a key factor affected the antioxidant system.•Certain interaction of antioxidant enzymes and gene expression existed. Non-racemic enrichment and oxidative stress were significantly observed after chiral PCB91 exposure, helpful to assess the environmental risk of chiral PCBs.