With respect to reducing the pressure on freshwater resources, treated wastewater (TWW) irrigation represents a sustainable alternative in agriculture. Due to their low quality and variable composition, TWW could entail harmful consequences for living organisms in terrestrial ecosystems. This study aims to evaluate how earthworm (Eisenia andrei) can modulate oxidative stress in bean plants (Vicia faba) that are irrigated over a course of 60 days with two doses of TWW (50 and 100%) in addition to a control condition (0%) irrigated with distilled water. This is achieved by measuring glutathione-S-transferase (GST) activity and malondialdehyde accumulation (MDA) in plants. Furthermore, catalase (CAT), GST, MDA, and acetylcholinesterase (AChE) activities of the earthworms are also assessed. Our results show that growth and physiological parameters are modified when applying TWW irrigation. Moreover, oxidative stress apprehended by GST activity and MDA accumulation is exacerbated in V. faba plants after exposure to increased TWW doses. Similarly, TWW irrigation enhances oxidative stress parameters in earthworms with a crucial decrease in AChE activity. In addition, the presence of earthworms increases growth and physiological parameters; it also results in a significant reduction in GST activity and MDA rate in V. faba plants. Our results provide new insights into the impact of TWW irrigation on soil organisms and the importance of earthworms in the reduction of oxidative stress in plants.
Keywords: Eisenia andrei; Treated wastewater; Vicia faba; oxidative stress.