Lower Concentrations of the Glyphosate-Based Herbicide Roundup® Cause Developmental Defects in Artemia salina

Roundup® is the most used glyphosate-based herbicide. During agricultural use it may directly contaminate existing aquatic ecosystems, posing severe concerns for the safety of nontarget terrestrial and aquatic organisms. We investigated the outcome of exposure to different concentrations of glyphosate in Roundup on cyst hatchability, toxicity, and teratogenic effects in the aquatic crustacean Artemia salina that inhabits diverse types of salt waters and, as a filter feeder, carries a greater risk of being exposed to pollutants. We found that exposure to 144 and 288 μg/ml glyphosate in Roundup resulted in cysts unable to complete diapause, and hatchability was completely inhibited during all exposure times tested (17-48 h). A glyphosate concentration of 288 μg/ml in Roundup was lethal to A. salina nauplii, and the lower concentrations (9, 18, 36, 72 μg/ml) had no significant effects on viability. In addition, sublethal and environmentally safe concentrations of glyphosate (0.72 μg/ml) in Roundup affected the early development of A. salina nauplii, with significantly decreased body lengths and reduced widths of the tail, abdomen, and head. The increased level of catalase activity observed in nauplii exposed to 0.72 μg/ml glyphosate for 24 h and those exposed to 7.2 and 72 μg/ml glyphosate for 48 h may be linked to excessive reactive oxygen species levels that had been induced by Roundup. In conclusion, Roundup containing >72 μg/ml glyphosate totally inhibited hatching of cysts and exerted toxic effects on A. salina nauplii. The increased prevalence of developmental defects in the nauplii observed at 0.72 μg/ml glyphosate signifies possible teratogenicity of Roundup exposure even at environmentally relevant concentrations of glyphosate, possibly due to disturbance of the antioxidant defenses, which needs further investigation. Environ Toxicol Chem 2023;42:1586-1594. © 2023 SETAC.