Two-Compartmental Toxicokinetic Model Predicts Interspecies Sensitivity Variation of Imidacloprid to Aquatic Invertebrates

作者：Su, Hang; Zhang, Qingjun; Huang, Kunyang; Wang, Wen-Xiong; Li, Huizhen^*; Huang, Zhoubing; Cheng, Fei; You, Jing

来源：Environmental Science and Technology, 2023, 57(29): 10532-10541.

DOI：10.1021/acs.est.3c01646

• neonicotinoids
• bioaccumulation
• internal exposure
• molecular docking
• chemical activity
• biologicaltraits

A two-compartmental toxicokinetic modelelucidates the interspeciessensitivity of imidacloprid to various aquatic invertebrates by distinguishingthe toxicologically relevant levels in the organisms. @@@ Interspecies sensitivity to the same chemical can beseveral ordersof magnitude different. Quantifying toxicologically internal levelsand toxicokinetic (TK) parameters is critical in elucidating the interspeciessensitivity. Herein, a two-compartmental TK model was constructedto characterize the uptake, distribution, and elimination kineticstoward interspecies sensitivity to an insecticide, imidacloprid. Imidaclopridexhibited the highest lethality to the insect Chironomusdilutus, followed by Lumbriculus variegatus, Hyalella azteca, and Daphnia magna. Interspecies sensitivity of imidaclopridto these invertebrates varied by & SIM;1000 folds based on waterconcentrations (LC50). Remarkably, the sensitivity variation decreasedto & SIM;50 folds based on the internal residues (LR50), highlightingthe critical role of TK in interspecies sensitivity. A one-compartmentalTK model failed to simulate the bioaccumulation of imidacloprid inthese invertebrates except for D. magna. Instead, a two-compartmental model successfully simulated the slowelimination of imidacloprid in the remaining three species by internallydistinguishing the highly dynamic (C (1))and toxicologically available (C (2)) fractions.We further showed that the species sensitivity of the invertebratesto imidacloprid was significantly related to C (2), demonstrating that C (2) was toxicologicallyavailable and responsible for the toxicity of imidacloprid. This mechanistic-basedmodel bridged the internal distribution of organic contaminants insmall invertebrates and the associated toxic potency.