Algal growth potential and oxidative stress in Ankistrodesmus falcatus exposed to waters from Xochimilco Lake system, México

The aim of this study was to assess the toxic effect of the water of Xochimilco Lake on a native microalgae species of the first trophic level, Ankistrodesmus falcatus. We evaluated oxidative stress (lipid peroxidation, and antioxidant activity of the enzymes: superoxide dismutase, catalase and glutathione peroxidase), and algal growth of A. falcatus, when exposed in bioassays to waters from three zones of Xochimilco Lake (urban, tourist, and agricultural), in four study periods; the responses were compared with those of a batch control. Water quality shows serious deterioration in the Xochimilco Lake system. Biomonitoring with biomarker responses provided information about the spatio-temporal impact of pollution on A. falcatus. Water samples of the three study zones of Xochimilco Lake induced oxidative stress in A. falcatus, and impaired its antioxidant enzymes and algal growth responses. Alteration detected in algal growth and oxidative stress of A. falcatus when exposed to waters from all sites and study periods make evident the toxic effect of the water from the Xochimilco Lake system.