Ecotoxicological Effects of Triclosan on Seedling Development and Antioxidant System of Canola Plants (Brassica napus L.)

Triclosan (TCS), a widely used antibacterial agent in personal care products, has raised concerns about its environmental impact, particularly on plant health. This study investigated the effects of TCS on canola (Brassica napus L.) seedlings. 60-day-old canola plants were exposed to 0, 1, 10, 100, and 1000 µg/L TCS for 30 days, after which physiological and biochemical parameters were analyzed. TCS exposure significantly impaired the antioxidant defense system and photosynthetic performance. At the highest concentration (1000 µg/L), chlorophyll fluorescence (Fv/Fm) declined by 15%, photosynthetic pigments decreased by 46%, while malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels nearly doubled compared to the control. Antioxidant enzyme activities: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOD), glutathione reductase (GR), and guaiacol peroxidase (GPOD) generally increased in response to TCS, except for dehydroascorbate reductase (DHAR), which declined. AO-S (soluble ascorbate), AO-B (bound ascorbate) showed a rapid increase at low concentrations and tended to decrease as the concentration increased. These results demonstrate that TCS disrupts redox homeostasis, photosynthesis, and growth in canola seedlings. Antioxidant and photosynthetic responses in canola can thus serve as sensitive biomarkers for monitoring TCS contamination in terrestrial ecosystems, highlighting potential risks for agriculture and environmental sustainability.