Earthworms (Eisenia fetida) were exposed to individual and binary mixture of imidacloprid (IMI) and dinotefuran (DIN) at 0.05 and 0.5 mg/kg for 28 days to investigate their bioaccumulation, transformation and toxicity. IMI was more easily absorbed by earthworms than DIN, and worms didn’t accumulate or generate toxic metabolites. The obvious accumulation of neonicotinoids during later period caused significant neural dysfunction, especially when exposed to high-concentration IMI. Meanwhile, oxidative stress indicated by decreased SOD/CAT activity (33.2 %-68.1 %) and increased MDA (38.4 %-55.0 %) was induced by binary exposure with high-concentration IMI. By contrast, coelomocytes responded earlier and more strongly than oxidative responses. Coelomocytes’ viability and mitochondrial membrane potential were inhibited (23.6 %-91.7 %) mainly by IMI and binary exposure. Coelomocytes’ lactate dehydrogenase activity exerted a fluctuating pattern, suggesting irregular disturbance on cellular functions. This study highlights the role of coelomocytes and the need to consider binary/multiple scenarios and transformation of neonicotinoids in their risk assessment to earthworms.

中文翻译：

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吡虫啉和呋虫胺在单次和二元暴露情景下在 Eisenia fetida 中的生物积累、转化和毒性


将蚯蚓 （Eisenia fetida） 暴露于 0.05 和 0.5 mg/kg 的吡虫啉 （IMI） 和呋虫胺 （DIN） 的单独和二元混合物中 28 d，以研究其生物积累、转化和毒性。IMI 比 DIN 更容易被蚯蚓吸收，并且蠕虫不会积累或产生有毒代谢物。新烟碱类药物在后期的明显积累导致明显的神经功能障碍，尤其是暴露于高浓度 IMI 时。同时，高浓度 IMI 的二元暴露诱导了 SOD/CAT 活性降低 （33.2 %-68.1 %） 和 MDA 增加 （38.4 %-55.0 %） 的氧化应激。相比之下，腔细胞的反应比氧化反应更早、更强烈。体细胞活力和线粒体膜电位主要受到 IMI 和二元暴露的抑制 （23.6 %-91.7 %）。腔细胞的乳酸脱氢酶活性产生波动模式，表明细胞功能受到不规则干扰。本研究强调了体腔细胞的作用以及在对蚯蚓的风险评估中考虑二元/多重情景和新烟碱类化合物转化的必要性。