Occupational exposure to 2,4-dichlorophenoxyacetic acid (2,4-D) and associated oxidative and genomic biomarkers among soybean farmers: a cross-sectional study

Background 2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely used for weed control in soybean cultivation. This study aimed to investigate hepatic and genetic damage biomarkers in farmers occupationally exposed to 2,4-D, widely used in soybean cultivation in southern Brazil (Rio Grande do Sul), in addition to estimate urinary 2,4-D concentrations as an indicator of recent exposure. Methods A cross-sectional study was conducted, including 54 occupationally exposed farmers and 51 non-exposed controls (organic farmers). Results Urinary 2,4-D was detected in 88.5% of the exposed group versus 25% of the controls ( p < 0.001). Creatine kinase (CK) was significantly elevated in the exposed group ( p < 0.05), suggesting possible muscle injury, while AST and ALT (classical liver enzymes) did not differ between groups. Oxidative stress markers showed a clear pattern of redox imbalance, with increased TBARS ( p < 0.001), increased CAT activity (p < 0.001), and reduced SOD activity (p < 0.001). Telomere length was significantly shorter in the exposed group ( p = 0.001). Use of personal protective equipment (PPE) was reported to be inadequate. Conclusion Occupational exposure to 2,4-D is associated with systemic oxidative stress and telomere shortening, even in the absence of transaminase elevation. This points to early hepatocellular vulnerability mediated by oxidative mechanisms rather than overt cytolysis. The study emphasizes the need for continuous monitoring of populations chronically exposed to chlorophenoxy herbicides.