Synergy between glyphosate- and cypermethrin-based pesticides during acute exposures in tadpoles of the common South American Toad Rhinella arenarum

• Published in: Chemosphere (Oxford) Vol. 112; pp. 70 - 76
• Main Authors: Brodeur, Julie Céline, Poliserpi, María Belén, D′Andrea, María Florencia, Sánchez, Marisol
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2014; Elsevier
• Subjects: Agriculture; Amphibia; Amphibians; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Bufonidae - growth & development; Constants; Corn; Culture; Cypermethrin; Drug Synergism; Ecotoxicology; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Environmental impact; Fundamental and applied biological sciences. Psychology; Glycine - analogs & derivatives; Glycine - toxicity; Glyphosate; Herbicides - toxicity; Insecticides - toxicity; Larva - drug effects; Lethal Dose 50; Mixtures; Pesticides; Ponds; Pyrethrins - toxicity; Reptilia. Amphibia; Toxicity; Water Pollutants, Chemical - toxicity; Wildlife management; South America; Argentina; America; Agriculture; Mixtures; Amphibians; Glyphosate; Cypermethrin; Pesticides; Bufonidae; Insecticide; Toxicity; Amphibia; Pyrethroids; Systemic; Synergism; Toxic association; Phosphorus Organic compounds; Toad; Poison interaction; Ecotoxicology; Acute; Organic phosphonate; Salientia; Bufo arenarum; Herbicide; Vertebrata; Larva; Aminoacid; Animal
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2014.02.065

•Glyphosate and cypermethrin are likely co-occur in wetlands supporting amphibians.•Little is known regarding how glyphosate and cypermethrin interact in mixtures.•Mixtures were significantly synergic in both combinations of products tested.•The synergy produced toxicities 2–9 times greater than concentration addition.•Synergies of such a great magnitude are uncommon in the literature. The herbicide glyphosate and the insecticide cypermethrin are key pesticides of modern management in soy and corn cultures. Although these pesticides are likely to co-occur in ephemeral ponds or aquatic systems supporting amphibian wildlife, the toxicological interactions prevailing in mixtures of these two pesticides have been little studied. The current study evaluated the toxicity of equitoxic and non-equitoxic binary mixtures of glyphosate- and cypermethrin-based pesticides to tadpoles of the common South American toad, Rhinella arenarum. Two different combinations of commercial products were tested: glyphosate Glifosato Atanor®+cypermethrin Xiper® and glyphosate Glifoglex®+cypermethrin Glextrin®. When tested individually, the formulations presented the following 96h-LC50s: Glifosato Atanor® 19.4mg aeL−1 and Glifoglex 72.8mg aeL−1, Xiper® 6.8mgL−1 and Glextrin® 30.2mgL−1. Equitoxic and non-equitoxic mixtures were significantly synergic in both combinations of commercial products tested. The magnitude of the synergy (factor by which toxicity differed from concentration addition) was constant at around twofold for all tested proportions of the glyphosate Glifoglex®+cypermethrin Glextrin® mixture; whereas the magnitude of the synergy varied between 4 and 9 times in the glyphosate Glifosato Atanor®+cypermethrin Xiper® mixture. These results call for more research to be promptly undertaken in order to understand the mechanisms behind the synergy observed and to identify and quantify the extent of its environmental impacts.