Although biocides at low concentrations have been used to control pests, they can be more harmful than industrial chemicals as humans are directly and frequently exposed to such biocides. Benzalkonium chloride (BAC or BKC) is a non-toxic substance used to control pests. Recently, BAC has been increasingly used as a component in humidifier disinfectants in Korea, raising a serious health concern. Moreover, it poses significant health hazards to workers handling the chemical because of direct exposure. In the present study, we aimed to evaluate the respiratory toxicity of BAC due to its inhalation at exposure concentrations of 0.8 (T1 group), 4 (T2 group) and 20 (T3 group) mg/m3. In our previous study on the acute inhalational toxicity of BAC, bleeding from the nasal cavity was observed in all the rats after exposure to 50 mg/m3 BAC. Therefore, in this study, 20 mg/m3 was set as the highest exposure concentration, followed by 4 and 0.8 mg/m3 as the medium and low concentrations for 6 h/day and 14 days, respectively. After exposure, recovery periods of 2 and 4 weeks were provided. Additionally, alveolar lavage fluid was analyzed in males of the BAC-exposed groups at the end of exposure and 2 weeks after exposure to evaluate oxidative damage. In the T3 group exposed to BAC, deep breathing, hoarseness, and nasal discharge were observed along with a decline in feed intake and body weight, and nasal discharge was also observed in the T1 and T2 groups. ROS/RNS, IL-1β, IL-6, and MIP-2 levels decreased in a concentration-dependent manner in the bronchoalveolar lavage fluid. Histopathological examination showed cellular changes in the nasal cavity and the lungs of the TI, T2, and T3 groups. As a result, it was confirmed that the target organs in the respiratory system were the nasal cavity and the lungs. The adverse effects were evaluated as reversible responses to oxidative damage. Furthermore, the no observed adverse effect level was found to be less than 0.8 mg/m3 and the lowest benchmark dose was 0.0031 mg/m3. Accordingly, the derived no-effect level of BAC was calculated as 0.000062 mg/m3.

中文翻译：

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在大鼠中进行了14天的吸入研究后，评估了苯扎氯铵的呼吸和全身毒性。

尽管低浓度的杀生物剂已被用于防治害虫，但与工业化学品相比，它们可能更具危害性，因为人类直接和经常暴露于此类杀生物剂中。苯扎氯铵（BAC或BKC）是用于控制害虫的无毒物质。最近，在韩国，BAC已越来越多地用作加湿器消毒剂的成分，引起了严重的健康问题。此外，由于直接接触，对操作该化学品的工人构成了重大健康危害。在本研究中，我们旨在评估BAC在暴露浓度为0.8（T1组），4（T2组）和20（T3组）mg / m3的吸入浓度下的呼吸毒性。在我们先前对BAC的急性吸入毒性的研究中，所有大鼠在暴露于50 mg / m3 BAC后都观察到鼻腔出血。因此，在这项研究中，将最高暴露浓度设置为20 mg / m3，然后分别将6小时/天和14天的中和低浓度设置为4和0.8 mg / m3。接触后，恢复期为2周和4周。此外，在暴露结束时和暴露后2周，对BAC暴露组的男性的肺泡灌洗液进行了分析，以评估氧化损伤。在暴露于BAC的T3组中，观察到深呼吸，声音嘶哑和流鼻涕，同时采食量和体重下降，在T1和T2组中也观察到流鼻涕。在支气管肺泡灌洗液中，ROS / RNS，IL-1β，IL-6和MIP-2水平呈浓度依赖性降低。组织病理学检查显示TI，T2和T3组的鼻腔和肺细胞发生变化。结果，确认了呼吸系统的目标器官是鼻腔和肺。不良反应被评估为对氧化损伤的可逆反应。此外，未观察到不良反应水平低于0.8 mg / m3，最低基准剂量为0.0031 mg / m3。因此，得出的BAC无效水平为0.000062 mg / m3。