Antioxidant enzyme activities as biomarkers of PAH pollution in Phragmites australis from a coastal wetland.

This study investigated the changes in antioxidant enzyme activities in Phragmites australis as a biomarker for polycyclic aromatic hydrocarbons (PAHs) pollution in Anzali Wetland, Southwest of the Caspian Sea, Iran. Sediment and plant samples were collected from 10 stations and the concentrations of PAHs in sediment as well as catalase, peroxidase and ascorbate peroxidase activities in roots, stems and leaves were analyzed. Significant differences in enzyme activities were observed among different parts of the plant (p < 0.05), in the following order: stem < leaf < root. A positive correlation was observed between sediment PAH levels and enzyme activities in P.australis. The oxidative stress index (OSI) also showed a strong relationship with PAH pollution, confirming that antioxidant enzymes are reliable biomarkers in aquatic ecosystems.