With the growing use of agrochemicals in Brazil, there is also a growing need for more realistic toxicity assessments that aid in understanding the potential risks of environmental-realistic agrochemical (mixture) exposures in the natural ecosystems. The aim of the present study was therefore to evaluate the lethal and sublethal effects of environmental realistic (single and mixture) concentrations of the pesticides DMA® 806 BR (active ingredient - a.i. 2,4-D) and Regent® 800 WG (a.i. fipronil) and sugarcane vinasse to the Neotropical cladoceran Ceriodaphnia silvestrii. This evaluation was carried out through lethal (survival), sublethal (reproduction and intrinsic rates of population increase - r) and post-exposure (feeding rate and also reproduction) tests conducted in situ and with water from mesocosms contaminated with the recommended doses of these compounds. The results showed high acute toxicity for treatments containing fipronil and vinasse when acting in isolation, with survival rates only returning to control values on the last sampling day (75 days post application). Reproduction of surviving cladocerans was reduced in all treatments until the end of the experiment and were potentiated effect in the mixture of the three test compounds. The intrinsic rates of population increase were reduced in all treatments except the single 2,4-D treatment. Post-exposure feeding rate and reproduction, however, were not impaired under the conditions analyzed. The results show the high toxicity of recommended doses of fipronil and vinasse (and especially their mixture) and the importance of evaluating the risks of agrochemical mixtures at environmental-realistic concentrations.

随着巴西越来越多地使用农用化学品，也越来越需要进行更现实的毒性评估，以帮助了解自然生态系统中环境现实农用化学品（混合物）暴露的潜在风险。因此，本研究的目的是评估农药 DMA® 806 BR（活性成分 - ai 2,4-D）和 Regent® 800 WG（氟虫腈）的环境实际（单一和混合物）浓度的致死和亚致死效应。 ) 和甘蔗酒糟到新热带枝角类动物Ceriodaphnia silvestrii。该评估通过致死（存活）、亚致死（繁殖和人口增长的内在速率 - r) 和暴露后（摄食率和繁殖）测试在原位进行，并且来自被推荐剂量的这些化合物污染的中间宇宙的水。结果表明，单独作用时含有氟虫腈和酒糟的处理具有高急性毒性，存活率仅在最后采样日（应用后 75 天）恢复到对照值。直到实验结束，所有处理中存活枝角类动物的繁殖都减少，并且在三种测试化合物的混合物中效果增强。除了单一的 2,4-D 治疗外，所有治疗的内在种群增长速率均降低。然而，在所分析的条件下，暴露后的摄食率和繁殖率没有受到影响。