Several studies have indicated the presence of the neonicotinoid insecticide imidacloprid (IMI) in aquatic ecosystems in concentrations up to 320.0 µg L⁻¹. In the present study, we evaluated the effects of the highest IMI concentration detected in surface water (320.0 µg L⁻¹) on the survival of Chironomus sancticaroli, Daphnia similis, and Danio rerio in three different scenarios of water contamination. The enzymatic activities of glutathione S-transferase (GST), catalase (CAT), and ascorbate peroxidase (APX) in D. rerio also were determined. For this evaluation, we have simulated a lotic environment using an indoor system of artificial channels developed for the present study. In this system, three scenarios of contamination by IMI (320.0 µg L⁻¹) were reproduced: one using reconstituted water (RW) and the other two using water samples collected in unpolluted (UW) and polluted (DW) areas of a river. The results indicated that the tested concentration was not able to cause mortality in D. similis and D. rerio in any proposed treatment (RW, UW, and DW). However, C. sancticaroli showed 100% of mortality in the presence of IMI in the three proposed treatments, demonstrating its potential to impact the community of aquatic nontarget insects negatively. Low IMI concentrations did not offer risks to D. rerio survival. However, we observed alterations in GST, CAT, and APX activities in treatments that used IMI and water with no evidence of pollution (i.e., RW and UW). These last results demonstrated that fish are more susceptible to the effects of IMI in unpolluted environments.

多项研究表明，在水生生态系统中，新烟碱类杀虫剂吡虫啉（IMI）的浓度最高为320.0 µg L ^-1。在本研究中，我们评估了在三种不同的水污染情况下，地表水中检测到的最高IMI浓度（320.0 µg L ^-1）对Sanicticaroli，Daphnia similis和Danio rerio的存活率的影响。谷胱甘肽S-转移酶（GST），过氧化氢酶（CAT），以及抗坏血酸过氧化物酶（APX）在酶活性D.鱼也被确定。对于此评估，我们使用为本研究开发的室内人工通道系统模拟了抽水环境。在该系统中，再现了三种受IMI污染的场景（320.0 µg L ^-1）：一种是使用再生水（RW），另一种是使用河流未污染（UW）和污染（DW）区域收集的水样。结果表明，在任何提议的处理方法（RW，UW和DW）中，测试浓度均不能导致D. similis和D. rerio的死亡。但是，C。sancticaroli在三种提议的治疗方法中，在存在IMI的情况下显示100％的死亡率，表明其对水生非靶标昆虫群落产生负面影响的潜力。低的IMI浓度不会给D. rerio生存带来风险。但是，我们观察到使用IMI和水但无污染迹象（即RW和UW）的处理中GST，CAT和APX活性的变化。这些最后的结果表明，在无污染的环境中，鱼类更容易受到IMI的影响。