PPG-SEA and NEEA/CRHEA/SHS, São Carlos School of Engineering, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos 13560-970, Brazil.
PPG-SEA and NEEA/CRHEA/SHS, São Carlos School of Engineering, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos 13560-970, Brazil.
Ecotoxicol Environ Saf. 2021 Feb;209:111778. doi: 10.1016/j.ecoenv.2020.111778. Epub 2020 Dec 15.
Increased use of pesticides in conventional agriculture implies potential risks to the environment. In aquatic ecosystems, benthic organisms may be exposed to pesticides via contaminated water and sediment, leading to several potential cascading effects on the food web. The aim of this study was to assess the functional implications of environmental realistic concentrations of the herbicide 2,4-D and the insecticide fipronil (alone and in combination) to the native tropical chironomid Chironomus sancticaroli. These two pesticides are widely applied to different crops and have frequently been detected (together) in surface water bodies in Brazil and elsewhere. Commercial products containing fipronil (Regent® 800WG) and 2,4-D (DMA® 806BR) were evaluated in 8-day toxicity tests for their effects on larval survival, growth (body length and biomass), head capsule width, development, and mentum deformities. Fipronil decreased the larval survival at the highest test concentration and the effective concentrations (EC) after eight days of exposure were: EC = 0.48 µg L (0.395-0.565), EC = 1.06 µg L (0.607-1.513), and EC = 3.70 µg L (1.664-5.736). All sublethal test concentrations of fipronil decreased the larval growth, causing reductions in biomass up to 72%. The two highest test concentrations of fipronil decreased the head capsule width and after exposure to 3.7 µg fipronil L, only half of the larvae reached the fourth instar. The incidence of deformities was increased by fipronil in a concentration dependent manner with an increase ranging from 23% to 75%. The highest test concentration of 2.4-D (426 µg L) decreased the head capsule width, but larval development was unaffected at all concentrations evaluated. In the mixture tests, antagonism was observed at lower fipronil concentrations and synergism at higher fipronil concentrations for growth. The incidence of deformities rose with increasing fipronil concentrations. The results showed that environmental realistic concentrations of fipronil may have serious ecological implications for C. sancticaroli populations and that a mixture with the herbicide 2,4-D can have synergistic effects, potentiating the risks to the aquatic ecosystem.
在常规农业中越来越多地使用农药意味着对环境存在潜在风险。在水生生态系统中，底栖生物可能会通过受污染的水和沉积物接触到农药，从而对食物网产生几种潜在的级联效应。本研究旨在评估环境现实浓度的除草剂 2,4-D 和杀虫剂氟虫腈（单独和组合）对本地热带摇蚊 Chironomus sancticaroli 的功能影响。这两种农药广泛应用于不同的作物，并且经常在巴西和其他地方的地表水休体中被检测到（一起）。评估了含有氟虫腈（Regent®800WG）和 2,4-D（DMA®806BR）的商业产品对幼虫存活率、生长（体长和生物量）、头壳宽度、发育和颏畸形的影响，进行为期 8 天的毒性试验。氟虫腈在最高测试浓度下降低了幼虫存活率，暴露 8 天后的有效浓度（EC）分别为：EC=0.48µg/L（0.395-0.565），EC=1.06µg/L（0.607-1.513）和 EC=3.70µg/L（1.664-5.736）。氟虫腈的所有亚致死测试浓度都降低了幼虫的生长，导致生物量减少高达 72%。氟虫腈的两个最高测试浓度降低了头壳宽度，在暴露于 3.7µg 氟虫腈/L 后，只有一半的幼虫达到第四龄。畸形的发生率随氟虫腈浓度的增加而增加，从 23%到 75%不等。最高测试浓度的 2,4-D（426µg/L）降低了头壳宽度，但所有评估浓度均未影响幼虫发育。在混合物测试中，较低浓度的氟虫腈表现出拮抗作用，较高浓度的氟虫腈表现出协同作用，对生长有协同作用。畸形的发生率随着氟虫腈浓度的增加而上升。结果表明，环境现实浓度的氟虫腈可能对 C.sancticaroli 种群产生严重的生态影响，并且与除草剂 2,4-D 的混合物可能具有协同作用，从而增加对水生生态系统的风险。
