Ecological Systems and Devices Annotation << Back Inactivation of the Toxic Effect of Cadmium Sulfate by Fullerene in an Enrichment Culture of Microalgae Dallakyan G.A. The combined effect of 1.5 mg/L cadmium sulfate and 5 mg/L fullerene on the growth of the green chlorococcal microalga Scenedesmus quadricauda (Turp.) Bréb. It was shown that the presence of fullerene stimulated algal growth, while the presence of cadmium sulfate, conversely, completely inhibited its growth compared to the control. When Scenedesmus guadricauda populations were exposed to cadmium sulfate and fullerene in combination, the toxic effect of cadmium sulfate was reduced. The most intense culture growth occurred when only fullerene was added to the culture medium, with photosynthetic effi ciency, cell number, and the proportion of viable cells increasing in the presence of fullerene. In the presence of fullerene, a prolongation of the stationary growth phase and a delayed transition of the culture to the death phase were observed, i.e., an increase in the lifespan of the population occurred. Apparently, fullerene in the culture medium acts as a sorbent and, on the one hand, alters the redox state of the medium, promoting favorable culture growth. Based on our work, fullerene can be used for potential water purifi cation and enhanced growth of aquatic organisms. Synthesizing fullerene-based substances would reduce production costs, as pure fullerene is expensive and uneconomical. Our research demonstrates the chemical basis for developing a compound capable of purifying aquatic ecosystems and restoring algae growth. Keywords: Scenedesmus guadricauda, cadmium sulfate, fullerene, cell viability, fluorescence, photosynthetic efficiency. DOI: 10.25791/esip.4.2026.1589 Pp. 45-51.