Zaman Samina, Minami Yuki, Honda Masato, Hanamoto Seiya
Graduate School of Natural Science and Technology, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan.
Environment Preservation Center, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan.
Sci Total Environ. 2025 Jul 15;986:179782. doi: 10.1016/j.scitotenv.2025.179782. Epub 2025 May 29.
Quaternary ammonium compounds (QACs)-ecotoxic biocidal contaminants linked to multidrug resistance-enter sewers owing to their domestic and commercial applications. Though high rates of removal of QACs in sewage treatment plants (STPs) were reported, little is known about their fates in on-site systems used in unsewered areas. Four times during a year, we monitored 14 QACs (benzalkonium chloride [BAC]-C8, C10, C12, C14, C16, C18; benzethonium chloride; cetylpyridinium chloride; dialkyldimethylammonium chloride [DDAC]-C8, C10, C12; and alkyltrimethylammonium chloride [ATAC]-C12, C16, C18), a disinfectant (chlorhexidine), and 15 drugs at 15 sites along river stretches and at an inlet and outlet of an STP in densely populated but still largely unsewered Japanese catchments. The maximum river-water concentrations of 2 ATACs were in the range of 10-100 μg/L; those of 3 BACs, 3 DDACs, 1 ATAC, and 3 drugs were 1-10 μg/L; and those of the others were < 1 μg/L. The higher mean river-water concentrations of 13 QACs removed in the STP at >1.5 log (>96.8 %) than those in STP effluent were attributable to untreated or poorly treated wastewater, consistent with the significant correlation of analyte composition between river water and raw sewage (r = 0.83, P < 0.01). A principal component analysis with tracer drugs linked 8 QACs of STP removal >2.5 log (>99.7 %) with untreated or poorly treated household wastewater, and the other 6 QACs with the total quantity of household wastewater or with both household and commercial wastewaters. Our findings will advance the understanding of managing QACs in unsewered areas.
季铵化合物（QACs）——与多重耐药性相关的具有生态毒性的杀菌污染物——因其在家庭和商业中的应用而进入下水道。尽管有报道称污水处理厂（STPs）对QACs的去除率很高，但对于它们在无下水道地区使用的现场系统中的归宿却知之甚少。我们一年中四次在日本人口密集但仍大多无下水道的集水区的15个河段地点以及一个污水处理厂的进水口和出水口监测了14种QACs（苯扎氯铵[BAC]-C8、C10、C12、C14、C16、C18；苄索氯铵；西吡氯铵；二烷基二甲基氯化铵[DDAC]-C8、C10、C12；以及烷基三甲基氯化铵[ATAC]-C12、C16、C18）、一种消毒剂（洗必泰）和15种药物。两种ATACs在河水中的最高浓度范围为10 - 100μg/L；3种BACs、3种DDACs、1种ATAC和3种药物的最高浓度为1 - 10μg/L；其他物质的最高浓度<1μg/L。污水处理厂去除率>1.5对数（>96.8%）的13种QACs在河水中的平均浓度高于其在污水处理厂出水中的浓度，这归因于未经处理或处理不佳的废水，这与河水和原污水中分析物组成的显著相关性一致（r = 0.83，P < 0.01）。一项使用示踪药物的主成分分析将污水处理厂去除率>2.5对数（>99.7%）的8种QACs与未经处理或处理不佳的家庭废水联系起来，而其他6种QACs与家庭废水总量或家庭和商业废水总量联系起来。我们的研究结果将推动对无下水道地区QACs管理的理解。
