Department of Civil and Environmental Engineering, University of Alberta, 9211-116 St. NW, Edmonton, AB T6G 1H9, Canada.
Water Services, The City of Calgary, P.O. Box 2100, Stn. M, Calgary, Alberta T2P 2M5, Canada.
Water Res. 2023 Oct 1;244:120454. doi: 10.1016/j.watres.2023.120454. Epub 2023 Aug 6.
Using a novel liquid chromatography-tandem mass spectrometry method with large volume direct injection and quantitation via isotope dilution, we evaluated the presence of 55 organic micropollutants in wastewater effluents, and locations within the Bow River and Elbow River watersheds in and around the city of Calgary, Alberta, Canada. In addition to establishing baseline micropollutant data for water utility operations, our study aimed to enhance our understanding of micropollutant behavior in the urban water cycle, assess the contributions of three wastewater treatment plants (WWTPs) to downstream receiving waters, explain the potential causes of total estrogenicity measured using the yeast-estrogen screen assay (YES), and prioritize a subset of substances for continuous monitoring. With data spanning 48 months and 95 river km, our results indicate the extensive persistence of metformin (antidiabetic), seasonality of N,N‑diethyl-m-toluamide (DEET, insect repellant), O-desmethylvenlafaxine (antidepressant metabolite), and sulfamethoxazole (antibiotic) in source waters, and sporadic detections of a well-known perfluoroalkyl substance (PFOA). The seasonality of pharmaceuticals at the sentinel downstream monitoring site appeared to coincide with river dilution while that of DEET was likely attributable to peak usage during the warmer months. Steroidal estrogens were rarely detected in wastewater effluents although total estrogenicity via YES was evident, suggesting the presence of less potent but more abundant non-steroidal estrogens (e.g., flame retardants, bisphenols, and phthalates). A conservative mass balance analysis suggests that the largest WWTP (serving a population of >1 million) consistently contributed the highest load of micropollutants, with the exception of metformin, which appeared to be influenced by a smaller WWTP (serving 115,000) that operates a different activated sludge process. We consider metformin, sucralose, diclofenac, and venlafaxine as more effective conservative tracers of wastewater pollution due to their notably higher concentrations and persistence in the Bow River compared to carbamazepine and caffeine, respectively. Finally, hierarchical clustering revealed a close association between E. coli and caffeine, supporting the use of caffeine as an indicator of short-term, untreated anthropogenic inputs. Overall, this study yields valuable insights on the presence, behavior, and sources of organic micropollutants in the urban water cycle and identifies indicators of anthropogenic impacts that are useful for prioritizing future monitoring campaigns in Calgary and elsewhere.
利用一种新型的液相色谱-串联质谱法，采用大体积直接进样和同位素稀释定量法，我们评估了加拿大阿尔伯塔省卡尔加里市及其周边的鲍尔河和埃尔博河流域的废水中 55 种有机微量污染物的存在情况以及位置。除了为水公用事业运营建立基线微量污染物数据外，我们的研究旨在增强我们对城市水循环中微量污染物行为的理解，评估三个污水处理厂（WWTP）对下游受纳水体的贡献，解释使用酵母雌激素筛选测定法（YES）测量的总雌激素的潜在原因，并优先选择一组物质进行连续监测。我们的研究结果涵盖了 48 个月和 95 公里的河流数据，表明二甲双胍（抗糖尿病药）在源头水中的广泛持久性、N,N-二乙基间甲苯酰胺（避蚊胺，驱虫剂）、O-去甲文拉法辛（抗抑郁药代谢物）和磺胺甲恶唑（抗生素）的季节性以及全氟辛烷磺酸（一种众所周知的全氟烷基物质）的零星检测。在下游监测点，药物的季节性似乎与河水稀释一致，而避蚊胺的季节性可能归因于温暖月份的使用高峰。尽管 YES 表明存在较弱但更丰富的非甾体雌激素（例如阻燃剂、双酚和邻苯二甲酸盐），但废水中很少检测到甾体雌激素。保守的质量平衡分析表明，最大的 WWTP（服务人口超过 100 万）始终贡献了最高的微量污染物负荷，二甲双胍除外，它似乎受到一个较小的 WWTP（服务 11.5 万人口）的影响，该 WWTP 采用不同的活性污泥工艺运行。由于在鲍尔河中浓度更高且持久性更强，我们认为二甲双胍、三氯蔗糖、双氯芬酸和文拉法辛是更有效的废水污染保守示踪剂，而卡马西平和咖啡因则分别如此。最后，层次聚类显示大肠杆菌和咖啡因之间存在密切关联，支持使用咖啡因作为短期、未经处理的人为输入的指标。总的来说，这项研究提供了有关有机微量污染物在城市水循环中的存在、行为和来源的有价值的见解，并确定了指示人为影响的指标，这些指标可用于为卡尔加里和其他地方的未来监测活动确定优先次序。
