The role of anionic surfactant in oxidative stress in aquatic ecosystems and its effect on Azolla filiculoides growth

Extensive consumption of surfactants in many industrial and commercial fields and the discharge of sewage containing these compounds into aquatic ecosystems endangers aquatic life. These compounds can bind to various biological molecules such as proteins, nucleic acids and lipids. They can destroy the structure of the cell through the increased production of reactive oxygen species. Therefore, in the present study, the effect of concentrations of 0, 10, 20, 30, and 40mg/L of linear alkylbenzene sulfonate surfactant for 7 days on the intensity of oxidative stress induced in Azolla filiculoides was determined based on malondialdehyde index. Then changes of some growth factors including total chlorophyll content and membrane stability index as well as antioxidant content of the plant including total carotenoid, catalase, phenolic and proline content were investigated. The lowest total chlorophyll content and membrane stability index, and the highest levels of malondialdehyde and proline were observed at 40 mg/L surfactant concentration. However, total phenol content was less affected by surfactant concentrations. In this way, the presence of concentrations of 30-40mg/L and above surfactant will cause in oxidative stress and induction of inhibitory effects on some growth indices.