Tris(2-chloroethyl) phosphate (TCEP) and tris(1‑chloro-2-propyl) phosphate (TCPP) are widely used as chlorinated organophosphate flame retardants (OPFRs) due to their fire-resistance capabilities. However, their extensive use has led to their permeation and pollution in aquatic environments. Using amphibians, which are non-model organisms, to test the toxic effects of OPFRs is relatively uncommon. This study examined the acute and chronic toxicity differences between TCEP and TCPP on tadpoles and evaluated the potential ecological risks to tadpoles in different aquatic environments using the risk quotient (RQ). In acute toxicity assay, the tadpole survival rates decreased with increased exposure time and concentrations, with TCEP exhibiting higher LC50 values than TCPP, at 305.5 mg/L and 70 mg/L, respectively. In the chronic assay, prolonged exposure to 300 μg/L of both substances resulted in similar adverse effects on tadpole growth, metamorphosis, and hepatic antioxidant function. Based on RQ values, most aquatic environments did not pose an ecological risk to tadpoles. However, the analysis showed that wastewater presented higher risks than rivers and drinking water, and TCPP posed a higher potential risk than TCEP in all examined aquatic environments. These findings provide empirical evidence to comprehend the toxicological effects of OPFRs on aquatic organisms and to assess the safety of aquatic environments.

中文翻译：

---

两种氯化有机磷阻燃剂（TCEP和TCPP）对大头蝌蚪的毒性比较及风险评估


磷酸三(2-氯乙基)酯(TCEP)和磷酸三(1-氯-2-丙基)酯(TCPP)由于其阻燃能力而被广泛用作氯化有机磷酸酯阻燃剂(OPFR)。然而，它们的广泛使用导致了它们对水生环境的渗透和污染。使用非模式生物两栖动物来测试 OPFR 的毒性作用相对不常见。本研究考察了TCEP和TCPP对蝌蚪的急性和慢性毒性差异，并利用风险商（RQ）评估了不同水生环境中蝌蚪的潜在生态风险。在急性毒性测定中，蝌蚪存活率随着暴露时间和浓度的增加而降低，TCEP 的 LC50 值高于 TCPP，分别为 305.5 mg/L 和 70 mg/L。在慢性试验中，长期暴露于 300 μg/L 的两种物质会对蝌蚪生长、变态和肝脏抗氧化功能产生类似的不利影响。根据 RQ 值，大多数水生环境不会对蝌蚪构成生态风险。然而，分析表明，在所有检查的水生环境中，废水的风险高于河流和饮用水，TCPP 的潜在风险高于 TCEP。这些发现为理解 OPFR 对水生生物的毒理学影响和评估水生环境的安全性提供了经验证据。