Comparative cytotoxicity and genotoxicity of commercial glyphosate-based herbicide formulations and co-formulants in human leukocyte and hepatocyte cell lines.

Abstract

Background: Risk assessments usually test active ingredients but not full commercial formulations. We compared cytotoxic and genotoxic effects of three glyphosate-based herbicides (Roundup Mega, Glyfos, Fozat-480) and two co-formulants (ROKAmin SR22, EMPIGEN BB) in human HL60 (leukocyte) and HepG2 (hepatocyte) cells.

Methods: Cells were exposed for 1 h to increasing concentrations (0.1-10,000 μM depending on formulation). Cytotoxicity was measured by propidium iodide staining; genotoxicity was assessed by the alkaline comet assay (tail DNA %, tail length, tail moment, Olive tail moment). Positive (100 μM H₂O₂) and negative controls were included. Data are means of three independent experiments.

Results: Cytotoxicity occurred at lower concentrations in HL60 than HepG2. Roundup Mega and Glyfos produced the strongest genotoxic responses; Roundup Mega increased tail length in HL60 from 0.1 μM, while Glyfos produced consistent genotoxicity in HepG2 from 100 μM. Co-formulants alone showed limited genotoxicity, though ROKAmin SR22 induced DNA% in tail at higher concentrations. Genotoxic effects often occurred at sub-cytotoxic concentrations.

Conclusion: Commercial GBH formulations can be more genotoxic than the active ingredient alone; formulation composition influences potency and target-cell sensitivity. These results support formulation-specific testing to improve human health risk assessment.