Erhunmwunse Nosakhare Osazee, Tongo Isioma, Omigie Kelvin
Laboratory for Ecotoxicology and Environmental Forensics (ECOTOX), University of Benin, PMB 1154, Benin City, Nigeria.
Department of Animal and Environmental Biology, Faculty of Life Sciences, University of Benin, PMB 1154, Benin City, Nigeria.
Ecotoxicology. 2023 Jan;32(1):127-134. doi: 10.1007/s10646-023-02625-y. Epub 2023 Jan 18.
Imidacloprid is a systemic insecticide that belongs to the neonicotinoid class of chemicals that act on the central nervous system of insects. Imidacloprid is used to control sucking insects, chewing insects such as termites, soil insects, and fleas on pets, as well as to treat structures, crops, soil, and seeds. As a result of these factors, this pesticide may end up in the aquatic environment via municipal discharges and runoff. Although the presence of imidacloprid in aquatic environments has been underreported as widespread, the toxic effects of this pesticide may have serious implications on aquatic organisms, particularly at environmentally relevant concentrations and demand more attention. Given this knowledge, the goal of this study was to investigate the effects of imidacloprid on Clarias gariepinus embryonic development. Clarias gariepinus embryos (3 h post-fertilization) were exposed to environmentally relevant concentrations of imidacloprid (10, 30, 100, and 500 µg/L) until 48 h post-fertilization using a modified fish embryo acute toxicity test (OECD TG 236). A stereomicroscope was used to assess hatchability, deformity, heart rate, and swimming speed as endpoints. According to our results of the developmental acute toxicity test, imidacloprid significantly reduced the hatching rate and heartbeats of C. gariepinus embryos. It also influenced the swimming kinematics of exposed embryos and caused teratogenic effects such as yolk sac rupture, pericardial oedema, lordosis, an abnormally shaped head, and altered epiboly. Our results allow us to conclude that imidacloprid is a toxic pesticide in the early life stages of C. gariepinus due to its high teratogenic potential.
吡虫啉是一种内吸性杀虫剂，属于新烟碱类化学物质，作用于昆虫的中枢神经系统。吡虫啉用于防治刺吸式口器害虫、咀嚼式口器害虫（如白蚁）、土壤害虫以及宠物身上的跳蚤，还用于处理建筑物、农作物、土壤和种子。由于这些因素，这种农药可能会通过城市排放和径流最终进入水生环境。尽管吡虫啉在水生环境中的存在情况被广泛低估，但这种农药的毒性作用可能会对水生生物产生严重影响，尤其是在与环境相关的浓度下，需要更多关注。基于这一认识，本研究的目的是调查吡虫啉对尖吻鲈胚胎发育的影响。使用改良的鱼类胚胎急性毒性试验（经合组织TG 236），将受精后3小时的尖吻鲈胚胎暴露于与环境相关浓度的吡虫啉（10、30、100和500μg/L）中，直至受精后48小时。使用体视显微镜评估孵化率、畸形、心率和游泳速度作为终点指标。根据我们发育急性毒性试验的结果，吡虫啉显著降低了尖吻鲈胚胎的孵化率和心跳。它还影响了暴露胚胎的游泳运动学，并导致致畸效应，如卵黄囊破裂、心包水肿、脊柱前凸、头部形状异常和外包异常。我们的结果使我们得出结论，由于吡虫啉具有很高的致畸潜力，它在尖吻鲈的早期生命阶段是一种有毒农药。
