The frequent detection of polychlorinated diphenyl ethers (PCDEs) in aquatic systems has aroused widespread concerns, however, their potential hazard to aquatic ecosystems has been poorly understood. Here the acute toxicity of 12 PCDE congeners was evaluated in three model aquatic organisms representing different trophic levels following OECD test guidelines, including green algae (Scenedesmus obliquus), water flea (Daphnia magna), and zebrafish (Danio rerio). Dose-dependent increases in growth inhibition and mortality were observed for all tested PCDE congeners. Most of the PCDE congeners, in particular 3,3′,4,4′-tetra-CDE, were highly toxic to the three aquatic organisms with EC₅₀ or LC₅₀ values below 1 mg L^-1. Their toxicities were generally comparable with those of certain polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Moreover, D. magna was the most sensitive species among the three aquatic organisms. In addition, the EC₅₀ or LC₅₀ values had an extremely significant correlation with the n-octanol-water partition coefficient (logK_ow) of the PCDE congeners. The established quantitative structure-property relationship (QSPR) models indicated that the molecular polarizability (α) could significantly influence the acute toxicity of PCDEs on Daphnia magna and Danio rerio, and the energy of the lowest unoccupied molecular orbital (E_LUMO) is the key factor of the acute toxicity of PCDEs in Scenedesmus obliquus. In addition, even at environmental levels, 3,3′,4,4′-tetra-CDE could induced seveve oxidative damages in the three aquactic species. These findings would contribute to the understanding of adverse effects of PCDEs in aquatic organisms.

水生系统中多氯二苯醚（PCDEs）的频繁检测引起了广泛关注，但其对水生生态系统的潜在危害却知之甚少。在这里，按照 OECD 测试指南，在代表不同营养水平的三种模式水生生物中评估了 12 种 PCDE 同源物的急性毒性，包括绿藻（Scenedesmusobliquus）、水蚤（Daphnia magna）和斑马鱼（Danio rerio）。对于所有测试的 PCDE 同源物，观察到生长抑制和死亡率的剂量依赖性增加。大多数 PCDE 同系物，尤其是 3,3',4,4'-tetra-CDE，对 EC ₅₀或 LC ₅₀的三种水生生物具有剧毒值低于 1 mg L ^-1。它们的毒性通常与某些多氯联苯 (PCB) 和多溴联苯醚 (PBDE) 的毒性相当。此外，D. magna是三种水生生物中最敏感的物种。此外，EC ₅₀或LC ₅₀值与PCDE 同系物的正辛醇-水分配系数（log K _ow）具有极其显着的相关性。建立的定量构性关系（QSPR）模型表明，分子极化率（α）可以显着影响 PCDEs 对Daphnia magna和Danio rerio的急性毒性，最低未占分子轨道（E _LUMO）的能量是影响斜栅藻PCDEs急性毒性的关键因素。此外，即使在环境水平上，3,3',4,4'-tetra-CDE 也可以在三种水生物种中引起严重的氧化损伤。这些发现将有助于了解 PCDE 对水生生物的不利影响。