Siddiqui Muhammad Usman, Sibtain Muhammad, Ahmad Farrukh, Zushi Yasuyuki, Nabi Deedar
Institute of Environmental Sciences and Engineering, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad 48000, Pakistan.
BioEnergy & Environmental Laboratory (BEEL), Masdar Institute Campus, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates.
J Xenobiot. 2024 May 1;14(2):554-574. doi: 10.3390/jox14020033.
Disinfection during tertiary municipal wastewater treatment is a necessary step to control the spread of pathogens; unfortunately, it also gives rise to numerous disinfection byproducts (DBPs), only a few of which are regulated because of the analytical challenges associated with the vast number of potential DBPs. This study utilized polydimethylsiloxane (PDMS) passive samplers, comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOFMS), and non-negative matrix factorization (NMF) spectral deconvolution for suspect screening of DBPs in treated wastewater. PDMS samplers were deployed upstream and downstream of the chlorination unit in a municipal wastewater treatment plant located in Abu Dhabi, and their extracts were analyzed using GC×GC-TOFMS. A workflow incorporating a multi-tiered, eight-filter screening process was developed, which successfully enabled the reliable isolation of 22 candidate DBPs from thousands of peaks. The NMF spectral deconvolution improved the match factor score of unknown mass spectra to the reference mass spectra available in the NIST library by 17% and facilitated the identification of seven additional DBPs. The close match of the first-dimension retention index data and the GC×GC elution patterns of DBPs, both predicted using the Abraham solvation model, with their respective experimental counterparts-with the measured data available in the NIST WebBook and the GC×GC elution patterns being those observed for the candidate peaks-significantly enhanced the accuracy of peak assignment. Isotopic pattern analysis revealed a close correspondence for 11 DBPs with clearly visible isotopologues in reference spectra, thereby further strengthening the confidence in the peak assignment of these DBPs. Brominated analogues were prevalent among the detected DBPs, possibly due to seawater intrusion. The fate, behavior, persistence, and toxicity of tentatively identified DBPs were assessed using EPI Suite™ and the CompTox Chemicals Dashboard. This revealed their significant toxicity to aquatic organisms, including developmental, mutagenic, and endocrine-disrupting effects in certain DBPs. Some DBPs also showed activity in various CompTox bioassays, implicating them in adverse molecular pathways. Additionally, 11 DBPs demonstrated high environmental persistence and resistance to biodegradation. This combined approach offers a powerful tool for future research and environmental monitoring, enabling accurate identification and assessment of DBPs and their potential risks.
城市三级污水处理过程中的消毒是控制病原体传播的必要步骤；不幸的是，这也会产生大量消毒副产物（DBP），由于与大量潜在DBP相关的分析挑战，其中只有少数受到监管。本研究利用聚二甲基硅氧烷（PDMS）被动采样器、全二维气相色谱（GC×GC）与飞行时间质谱（TOFMS）联用，以及非负矩阵分解（NMF）光谱去卷积对处理后废水中的DBP进行可疑物筛查。在位于阿布扎比的一座城市污水处理厂的氯化单元上游和下游部署了PDMS采样器，并使用GC×GC-TOFMS对其提取物进行分析。开发了一个包含多层、八级筛选过程的工作流程，该流程成功地从数千个峰中可靠地分离出22种候选DBP。NMF光谱去卷积使未知质谱与NIST库中可用参考质谱的匹配因子得分提高了17%，并有助于鉴定另外七种DBP。使用亚伯拉罕溶剂化模型预测的DBP的一维保留指数数据和GC×GC洗脱模式与它们各自的实验对应物（NIST网络书中的测量数据以及候选峰观察到的GC×GC洗脱模式）的紧密匹配显著提高了峰归属的准确性。同位素模式分析显示，11种DBP与参考光谱中清晰可见的同位素异构体有密切对应关系，从而进一步增强了对这些DBP峰归属的信心。溴化类似物在检测到的DBP中普遍存在，可能是由于海水入侵。使用EPI Suite™和CompTox化学物质仪表板评估了初步鉴定的DBP的归宿、行为、持久性和毒性。这揭示了它们对水生生物具有显著毒性，包括某些DBP的发育、诱变和内分泌干扰作用。一些DBP在各种CompTox生物测定中也表现出活性，表明它们参与了不良分子途径。此外，11种DBP表现出高环境持久性和抗生物降解性。这种综合方法为未来的研究和环境监测提供了一个强大的工具，能够准确识别和评估DBP及其潜在风险。
