Exposure to environmental concentrations of 4-n-nonylphenol: impacts on oxidative stress in guppy (Poecilia vivipara).

This study examined the effects of 4-nonylphenol (NP) exposure on the enzymatic activities of P. vivipara (guppy) following 96 h of exposure to concentrations of 5, 15, and 50 μg L^-1. The results indicated significant alterations in antioxidant and biotransformation enzyme activities in the liver but with no observed mortality. Specifically, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) decreased at higher concentrations, particularly in females. These enzymes are essential for mitigating reactive oxygen species (ROS), and their inhibition could result in cellular damage. Biotransformation enzymes exhibited changes, especially in males, with elevated 7-ethoxyresorufin-O-deethylase (7-EROD) and glutathione S-transferase (GST) activities at lower concentrations of NP. While these findings align with previous studies, they also reveal inconsistencies in the literature, particularly concerning the effects on GST activity. The study further identified sex-specific patterns, though these results should be interpreted cautiously due to potential confounding factors. Overall, this research underscores the need for additional studies to elucidate the toxicological mechanisms of NP and its potential ecological impacts. It emphasizes the importance of considering species-specific differences, exposure duration, and environmental conditions in assessing the risks associated with NP exposure.