Toxic and genotoxic effects of Roundup on tadpoles of the Indian skittering frog (Euflictis cyanophlyctis) in the presence and absence of predator stress

Journal or Publishing Institution: Aquatic Toxicology

Study: http://www.sciencedirect.com/science/article/pii/S0166445X1300026X

Author(s): Yadav, S.S., Giri, S., Singha, U., Boro, F. and Giri, A.

Article Type: Peer Reviewed Study

Abstract: Glyphosate, a post emergent herbicide, has become the backbone of no-till agriculture and is considered safe for animals. However, the impact of glyphosate on non-target organisms, especially on amphibians, is the subject of major concern and debate in recent times. We examined the toxic and genotoxic effects of Roundup, a commercial formulation of glyphosate, in the tadpoles of the Indian skittering frog (Euflictis cyanophlyctis). Roundup at different concentrations (0, 1, 2, 3, 4 and 8 mg acid equivalent (ae)/L), tested in a 2 × 6 factorial design in the presence and absence of predator stress, induced concentration-dependent lethality in tadpoles. The 96-h LC₅₀ for Roundup in the absence and presence of predator stress were 3.76 mg ae/L and 3.39 mg ae/L, respectively. The 10-day LC₅₀ value for Roundup was significantly lower, 2.12 mg ae/L and 1.91 mg ae/L in the absence and presence of predator stress, respectively. Lower concentrations of Roundup (1, 2 and 3 mg ae/L) induced the formation of micronuclei (MN) in the erythrocytes of tadpoles at 24-h (F_3,56 = 10.286, p < 0.001), 48-h (F_3,56 = 48.255, p < 0.001), 72-h (F_3,56 = 118.933, p < 0.001) and 96-h (F_3,56 = 85.414, p < 0.001) in a concentration-dependent manner. Presence of predator stress apparently increased the toxicity and genotoxicity of Roundup; but these effects were not statistically significant. These findings suggest that Roundup at environmentally relevant concentrations has lethal and genotoxic impact on E. cyanophlyctis; which may have long-term fitness consequence to the species.

Keywords: Roundup, Glyphosate, Amphibian, Micronucleus, Genotoxicity, Predator Stress; Animals, Anura, Drug Dose-Response Relationship, Erythrocytes, Food Chain, Glycine, Herbicides, Larva, Longevity, Micronucleus Tests, Physiological Stress; Genetics, Growth & Development, Physiology, Drug Effects, Metabolism, Analogs & Derivatives, Toxicity; Nontarget Organisms, Tadpoles, Frogs

Citation: Yadav, S.S., Giri, S., Singha, U., Boro, F. and Giri, A., 2013. Toxic and genotoxic effects of Roundup on tadpoles of the Indian skittering frog (Euflictis cyanophlyctis) in the presence and absence of predator stress. Aquatic Toxicology, 132, pp.1-8.