Does the herbicide active ingredient nicosulfuron exhibit ecotoxic effects on aquatic organisms and genotoxic actions...

Environmental contamination by pesticides is a major concern, and herbicides are the most widely applied plant protection products in agriculture. Nicosulfuron is a sulfonylurea herbicide widely used in post-emergence weed control in maize and is relatively mobile, which may increase its bioavailability in soil and water. These factors raise concern regarding effects on non-target organisms. The aim of this study was to investigate the effects of nicosulfuron on: (1) micronucleus induction in Vicia faba cells; (2) population growth rate of microalgae Raphidocelis subcapitata; (3) mobility of microcrustacean Daphnia magna; and (4) reproduction of the rotifer Brachionus calyciflorus. Nicosulfuron stimulated population growth of R. subcapitata after 72 h exposure. In D. magna, only the highest tested concentration (100 mg/L) produced a weak acute effect with 10% immobilization after 48 h. In B. calyciflorus, no clear concentration-dependent inhibition of reproduction was observed with highest concentration (15.36 mg/L) similar to control. In V. faba, nicosulfuron was cytotoxic at the highest concentrations tested and genotoxic, inducing micronuclei at 3.12 mg/L. To the best of our knowledge, this is the first report of genotoxic effects of nicosulfuron examined in a plant model. Because the concentrations tested were markedly higher than those typically reported in environmental waters, these present results need to be interpreted primarily as a hazard-based screening of biological responses rather than a direct environmental risk characterization. Overall, our findings advance knowledge of effects of nicosulfuron on non-target organisms and support the need for further studies under environmentally relevant exposure scenarios.