Environmental Implications of Intensive Pesticide Use on Sugar Cane Yields

Sugar cane cultivation in Brazil relies on pesticides like fipronil and 2,4-D, raising concerns about long-term environmental persistence and plant uptake. This study assessed the long-term persistence, uptake, and translocation of 2,4-D, fipronil, and its metabolites (sulfone and sulfide) in sugar cane tissues under field conditions, using an experimental farm with controlled pesticide applications. Samples of fresh leaves, dry leaves, and bagasse were collected in 2023 from tillers and ripened cane following pesticide applications carried out in 2019 (fipronil) and 2021 (2,4-D). Residues were measured using a validated method based on QuEChERS, with quantification by liquid chromatography-tandem mass spectrometry, revealing distinct profiles. Fipronil metabolites were detected in fresh leaves at low μg kg^-1 levels, particularly in tillers, which may suggest more retention and limited systemic mobility. Conversely, 2,4-D residues were only found in dry leaves of tillers (3.4-12.0 μg kg^-1), consistent with its high polarity and redistribution to senescing tissues. No compounds were detected in the bagasse. These distinct distribution patterns reflect the contrasting physicochemical properties of the analytes: the lipophilic fipronil metabolites could remain in living foliar tissues, while the hydrophilic 2,4-D accumulates in senescing leaves with the potential for environmental recirculation. The findings provide field-based evidence of long-term pesticide persistence in sugar cane, underscoring the need for continuous risk assessment and the adoption of more sustainable crop management practices.