The Effects of Triclosan on Physiological and Photosynthetic Characteristics of Chlorella vulgaris

Triclosan has been widely used as addition ingredient in personal care and medical antibacterial products, and the increasing amounts of triclosan discharged in aquatic environments pose a potential risk to aquatic ecological systems. In this study, we investigated the effects of exposure to varying triclosan concentrations on the growth, chlorophyll fluorescence and antioxidant enzyme activity ofChlorella vulgaris. The results showed that low-concentration triclosan (<0.75 mg/L) can stimulate the growth ofChlorella vulgaris, whereas 1.05 mg/L triclosan exhibited significant inhibition. Low-concentration triclosan (<0.75 mg/L) could improve the tolerance and utilization ability ofChlorella vulgarisin relation to strong light. We observed a significant increase in the malondialdehyde content ofChlorella vulgarisexposed to 1.05 mg/L triclosan. The intracellular superoxide dismutase and catalase (CAT) activities ofChlorella vulgarisexposed to triclosan were higher than the control groups, and the increase in this activity was positively correlated with the concentration of triclosan. The results also showed that excessive H2O2may in turn damage the CAT structure and eventually inactivate CAT activity whenChlorella vulgarisis exposed to 1.05 mg/L triclosan. This study provided a theoretical basis which can be used to evaluate the ecological risk of triclosan in the aquatic environment.Keywords:triclosan;Chlorella vulgaris;eco-toxicological effect;chlorophyll fluorescence