尽管它们对环境有影响,有关农药混合物的生态毒理学信息相对匮乏。本研究旨在确定单个农药制剂及其混合物(杀虫剂和杀菌剂)的生态毒性,在马铃薯的生产周期中应用,根据哥斯达黎加拉丁美洲地区的农业实践。采用了两种基准生物:大型水蚤和苜蓿。首先,对单个制剂(百菌清,propineb,溴氰菊酯+吡虫啉,ziram,硫环脲和毒死rif)揭示了活性成分(a.i.)的可用EC50与它们各自对D.magna的配方之间的差异;相反,无法从科学文献中检索到有关紫花苜蓿的信息进行比较。总的来说,对D.magna的急性毒性高于紫花苜蓿。此外,不能在紫花苜蓿上确定相互作用,因为百菌清制剂在高水平时没有毒性,且对丙尼肽的浓度-反应无法拟合以获得IC50值.由溴氰菊酯+吡虫啉组成的商业制剂遵循浓度添加模型(当与从单独的a.i.检索到的参数进行比较时),并且评估了其他三种混合物(I:百菌清-丙丙三醇-溴氰菊酯+吡虫啉;II:百菌清-丙三醇-硫环;III:百菌清-丙三醇-对D.因此表明急性毒性低于它们的单独成分。随后的长期研究表明,毒性最强的混合物(II)之一在亚致死浓度下对D.magna的繁殖产生了负面影响,这表明如果这些农药在淡水系统中共存,这种混合物会对该物种构成风险。这些发现提供了有用的数据,可以更好地估计与使用农用化学品有关的实际农业实践的影响。
Despite their environmental implications, ecotoxicological information regarding pesticide mixtures is relatively scarce. This study aimed to determine the ecotoxicity of individual pesticide formulations and their mixtures (insecticides and fungicides), which are applied during the production cycle of potato, according to agricultural practices from a Latin American region in Costa Rica. Two benchmark organisms were employed: Daphnia magna and Lactuca sativa. First, the evaluation of individual formulations (chlorothalonil, propineb, deltamethrin+imidacloprid, ziram, thiocyclam and chlorpyrifos) revealed differences between available EC50 for active ingredients (a.i.) and their respective formulations toward D. magna; on the contrary, no information could be retrieved from scientific literature for comparison in the
case of L. sativa. In general, acute toxicity was higher toward D. magna than L. sativa. Moreover, interactions could not be determined on L. sativa, as the chlorothalonil formulation was not toxic at high levels and the concentration-response to propineb could not be fitted to obtain an IC50 value. The commercial formulation composed of deltamethrin+imidacloprid followed the concentration addition model (when compared with parameters retrieved from individual a.i.) and the other three mixtures evaluated (I: chlorothalonil-propineb-deltamethrin+imidacloprid; II: chlorothalonil-propineb-ziram-thiocyclam; III: chlorothalonil-propineb-chlorpyrifos) produced an antagonistic effect on D. magna, thus suggesting less acute toxicity than their individual components. Subsequent chronic studies showed that one of the most toxic mixtures (II) negatively affected D. magna reproduction at sublethal concentrations indicating that this mixture poses a risk to this species if these pesticides co-exist in freshwater systems. These findings provide useful data to better estimate the impact of real agricultural practices related to the use of agrochemicals.