Ecotoxicity of nicosulfuron and S-metolachlor-based herbicides on non-target plants

Herbicides have been extensively researched due to widespread use in agriculture, consequently raising concerns regarding their environmental impact and potential adverse effects on non-target organisms, including humans. Nicosulfuron is a post-emergence herbicide used to control annual or perennial grasses and broad-leaved weeds. In contrast, S-metolachlor is primarily employed as a pre-emergence herbicide for managing annual grasses and certain broad-leaved weeds in intensive cropping systems. This study aimed to assess the effects of two commercial herbicides, one based upon nicosulfuron and the other upon S-metolachlor active ingredients, on the early developmental stages of the plant models Lactuca sativa L. (lettuce), Raphanus sativus (radish), Pennisetum glaucum (L.) R. Br. (millet), and Triticum aestivum (wheat), as evidenced from germination and seedling development bioassays. Results indicated that all plant models exhibited phytotoxic responses, including inhibited germination, reduced germination speed index, and impaired seedling growth and development, ultimately leading to decreased fresh weight. Among the plant species tested, T. aestivum was the most sensitive, while R. sativus was the least affected. Data suggest that nicosulfuron and S-metolachlor-based herbicides exert significant phytotoxic effects on non-target plants, offering valuable insights for future research on the environmental impacts of these substances.