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The acute toxicity of two herbicide formulations, namely, the 57.71 % dicamba (DIC)-based Banvel and the 48 % glyphosate (GLY)-based Credit, alone as well as the binary mixture of these herbicides was evaluated on late-stage Rhinella arenarum larvae (stage 36) exposed under laboratory conditions. Mortality was used as an endpoint for determining acute lethal effects, whereas the single-cell gel electrophoresis (SCGE) assay was employed as genotoxic endpoint to study sublethal effects. Lethality studies revealed LC50 values of 358.44 and 78.18 mg L DIC and GLY for Banvel and Credit, respectively. SCGE assay revealed, after exposure for 96 h to either 5 and 10 % of the Banvel LC50 concentration or 5 and 10 % of the Credit LC50 concentration, an equal significant increase of the genetic damage index (GDI) regardless of the concentration of the herbicide assayed. The binary mixtures of 5 % Banvel plus 5 % Credit LC50 concentrations and 10 % Banvel plus 10 % Credit LC50 concentrations induced equivalent significant increases in the GDI in regard to GDI values from late-stage larvae exposed only to Banvel or Credit. This study represents the first experimental evidence of acute lethal and sublethal effects exerted by DIC on the species, as well as the induction of primary DNA breaks by this herbicide in amphibians. Finally, a synergistic effect of the mixture of GLY and DIC on the induction of primary DNA breaks on circulating blood cells of R. arenarum late-stage larvae could be demonstrated. [ABSTRACT FROM AUTHOR]

Ecotoxicity studies using two glyphosate-based formulations (Eskoba® and Sulfosato Touchdown®) were undergone with three microcrustacean species to establish their LC values and to evaluate the efficacy of cleaning treatments with UV/HO.Samples were collected at the beginning of the process −50 mg acid equivalent per liter of glyphosate without HO and at different treatment timepoints: 2, 4, and 6 h. Three microcrustacean species were used as biological models.The Eskoba® LC ranged between 14.49 and 95.23 acid equivalents (a.e.) mg Land for Sulfosato Touchdown® between 0.31 and 1.74 a.e. mg L. The glyphosate-based formulations registered the following order of sensitivities: Ceriodaphnia dubia > Daphnia magna > Notodiaptomus conifer. The treatment duration and mortality (%) were negative and significantly correlated for both formulations, indicating that the remediation process diminished the glyphosate concentration. Therefore, microcrustacean mortality decreased linearly with the remediation time. C. dubia and N. conifer were more sensitive than the holarctic D. magna to the remediation process, since the first two species showed greater percentage of mortality at 6 h of processes, compared with D. magna, for both formulations evaluated. Sulfosato Touchdown® was more toxic but showed greater degradability than Eskoba®. The results provide relevant information regarding (1) the urgency to clearly identify the additives on product labels, (2) the efficiency of UV/HO process for reducing adverse effects of two glyphosate-based formulations, and (3) the importance of developing studies to evaluate the effectiveness of cleaner technologies with an emphasis on microcrustacean species as biological models. [ABSTRACT FROM AUTHOR]