In the present study, fipronil degradation was evaluated in typical chlorination conditions (fipronil: 20 μg L⁻¹; free chlorine concentration: 2 mg L⁻¹; pH 7.5; 25 ^○C). Fipronil was quickly degraded by chlorination with half-time life of 2.08 min, achieving 95% of degradation in 15 min of reaction. For identification and elucidation of its disinfection by-products, fipronil solutions (2.0 mg L⁻¹) were chlorinated at different contact times. Six by-products were identified and their structural formulas were elucidated by high-resolution mass spectrometry. Lastly, the toxicity of the unreacted and chlorinated solutions was evaluated using in vitro, in vivo, and in silico assays. Unreacted and chlorinated solutions were toxic to Artemia salina nauplii with an increase on toxic effects after 24 h of reaction time. No estrogenicity and cytotoxicity were observed for the tested solutions using re-engineered bioluminescent yeast estrogen screen and colorimetric MTT assays, respectively. According to quantitative structure-activity relationship methodology, chlorination may produce a more mutagenic compound than the precursor fipronil. The generated disinfection by-products also proved to be developmental toxicant, although it was not possible to measure their relative potency in relation to the parent compound.

（：20微克大号氟虫腈在本研究中，氟虫腈降解在典型氯化条件进行评价^-1 ;：2毫克的L游离氯浓度^-1 ; pH为7.5; 25 ^○ C）。Fipronil通过氯化迅速降解，半衰期为2.08分钟，在15分钟的反应中达到95％的降解率。为了鉴定和阐明其消毒副产物，在不同的接触时间对氟虫腈溶液（2.0 mg L ^-1）进行了氯化处理。鉴定出六种副产物，并通过高分辨率质谱法阐明了其结构式。最后，使用体外，体内和计算机分析法评估未反应和氯化溶液的毒性。未反应的氯化溶液对反应时间24小时后，卤虫无节幼体的毒性作用增加。分别使用重新设计的生物发光酵母雌激素筛选和比色MTT分析，未观察到测试溶液的雌激素性和细胞毒性。根据定量的构效关系方法，氯化可能比前者氟虫腈产生更多的诱变化合物。尽管无法测量其相对于母体化合物的相对效力，但所产生的消毒副产物也被证明是发育性有毒物质。