Toxicity evaluation of metsulfuron-methyl, nicosulfuron, and methoxyfenozide as pesticides in Indonesia

Abstract Pesticides are substances widely used to control or eliminate pests, including weeds, insects, and other harmful organisms. Agricultural pesticides, in particular, must meet specific safety and quality standards before being marketed. In this study, the acute and chronic toxicity of metsulfuron-methyl, nicosulfuron, and methoxyfenozide were predicted using quantitative structure–activity relationship (QSAR) analysis through the EPI Suite program. Furthermore, in vivo testing was conducted to evaluate skin irritation, eye irritation, and skin sensitization based on modified OECD 404, OECD 405, and OECD 406 guidelines. The QSAR analysis indicated that all three pesticides have low acute and chronic toxicity profiles. In the skin irritation and skin sensitization tests, metsulfuron-methyl (100 mg), nicosulfuron (125 mg), and methoxyfenozide (150 mg) showed a primary irritation score of 0 and a sensitization score of 0, indicating no irritant or sensitization effects on rabbit and guinea pig skin. In the eye irritation test, metsulfuron-methyl caused mild conjunctival redness and eyelid swelling, with an average irritation score of 1.25, classifying it as a mild irritant (Category 2B). In contrast, nicosulfuron and methoxyfenozide did not cause any observable eye irritation, with an irritation score of 0. These findings suggest that while metsulfuron-methyl may cause mild eye irritation, all three pesticides are non-irritating to the skin and do not induce skin sensitization. This research provides essential toxicological data for regulatory safety evaluations and underscores the importance of integrating QSAR analysis with in vivo methods to assess pesticide safety comprehensively.