Cypermethrin

Brodeur et. al, 2014

Julie Céline Brodeur, María Belén Poliserpi, María Florencia D’Andrea, Marisol Sánchez, “Synergy between glyphosate- and cypermethrin-based pesticides during acute exposures in tadpoles of the common South American Toad Rhinella arenarum,” Chemosphere, 2014, 112:70-76, DOI: 10.1016/j.chemosphere.2014.02.065.

ABSTRACT:

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 nonequitoxic 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 96 h-LC50s: Glifosato Atanor 19.4 mg ae L1 and Glifoglex 72.8 mg ae L1 , Xiper 6.8 mg L1 and Glextrin 30.2 mg L1. 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.

Brodeur et. al, 2016

Julie Celine Brodeur, Solene Malpel, Ana Belen Anglesio, Diego Cristos, María Florencia D’Andrea, María Belen Poliserpi, “Toxicities of glyphosate- and cypermethrin-based pesticides are antagonic in the tenspotted livebearer fish (Cnesterodon decemmaculatus),” Chemosphere, 2016, 155:429-435, DOI:  10.1016/j.chemosphere.2016.04.075.

ABSTRACT:

Although pesticide contamination of surface waters normally occurs in the form of mixtures, the toxicity and interactions displayed by such mixtures have been little characterized until now. The present study examined the interactions prevailing in equitoxic and non-equitoxic binary mixtures of formulations of glyphosate (Glifoglex®) and cypermethrin (Glextrin®) to the tenspotted livebearer (Cnesterodon decemmaculatus), a widely distributed South American fish. The following 96 h-LC50s were obtained when pesticide formulations were tested individually: Glifoglex® 41.4 and 53 mg ae glyphosate/L; Glextrin® 1.89 and 2.60 mg cypermethrin/L. Equitoxic and non-equitoxic mixtures were significantly antagonic in all combinations tested. The magnitude of the antagonism (factor by which toxicity differed from concentration addition) varied between 1.37 and 3.09 times in the different non-equitoxic mixtures tested. Antagonism was due to a strong inhibition of cypermethrin toxicity by the glyphosate formulation, the toxicity of the cypermethrin-based pesticide being almost completely overridden by the glyphosate formulation. Results obtained in the current study with fish are radically opposite to those previously observed in tadpoles where synergy was observed when Glifoglex® and Glextrin® were present in mixtures.  FULL TEXT