Does the herbicide active ingredient nicosulfuron show ecotoxic effects on aquaticorganisms and genotoxic effects on terrestrial plants?

Environmental contamination by pesticides is of great concern, and herbicides are the most applied in agriculture. One of the most widely used herbicides in maize fields for post-emergent control of weeds such as annual and perennial grasses and some broad-leaf plants is based on the active ingredient nicosulfuron. The nicosulfuron molecule is relatively mobile and can become bioavailable in soil and water, representing a toxicological risk to non-target organisms. Hence, this study investigated the effects of nicosulfuron on: (1) the induction of micronuclei in Vicia faba cells; (2) the population growth rate of the microalgae Raphidocelis subcapitata; (3) the mobility of the microcrustacean Daphnia magna; and (4) the reproduction of the rotifer Brachionus calyciflorus . Nicosulfuron stimulated the population growth of R. subcapitata after 72 h of exposure. In contrast, the highest concentration (100 mg L ^-1 ) applied to D. magna completely inhibited the mobility of the individuals after 48 h of exposure, and the highest concentration (15.36 mg L ^-1 ) applied to B. calyciflorus inhibited their reproduction by 100%. Furthermore, nicosulfuron was cytotoxic at the highest concentrations tested with V. faba, and genotoxic at a concentration of 3.12 mg L ^-1 . As far as we are aware, this is the first time the genotoxic effects of nicosulfuron have been tested in a plant model, and we demonstrate that the active compound is ecotoxic in aquatic media. Our study advances the knowledge of the effects of nicosulfuron in non-target organisms and the risk of its presence in the environment.