In-sewer stability of human excreted biomarkers is a critical factor of wastewater-based epidemiology in back-estimating illicit drug and pharmaceutical use in the community. Biomarker stability has been investigated in sewers with the presence of biofilms, but the understanding in sewer sediments is still lacking. This study for the first time employed a laboratory sediment reactor to measure 18 illicit drug and pharmaceutical biomarkers under gravity sewer environments with the presence of sediments. Biomarkers exhibited various stability patterns due to transformation processes occurring in the bulk wastewater and sediments. The attenuation of a biomarker by sediments is driven by complex processes involving biodegradation, diffusion, and sorption, which is directly proportional to the ratio of sediment surface area against wastewater volume. The sediment-driven transformation coefficients of biomarkers are higher than the accordingly biofilm-mediated rates because of stronger microbial activities in sediments. Additionally, the stability of most biomarkers was insensitive to the natural pH variation in sewers, except for a few compounds (e.g., methadone, ketamine, and paracetamol) susceptible to pH changes. In general, this study delineates the stability data of various biomarkers in gravity sewers with sediments, which are novel and long-missing information for wastewater-based epidemiology and improve the reliability of back-estimation in complex sewer networks.

中文翻译：

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下水道沉积物中的非法药物和药品的转化。

人类排泄的生物标志物在污水中的稳定性是基于废水的流行病学在反算社区中非法药物和药物使用中的关键因素。已经对存在生物膜的下水道中生物标志物的稳定性进行了研究，但对下水道沉积物的认识仍然缺乏。这项研究首次使用实验室沉积物反应器在重力下水道环境下有沉积物的情况下测量18种非法药物和药物生物标志物。由于大量废水和沉积物中发生转化过程，生物标志物表现出各种稳定性模式。沉积物对生物标志物的衰减是由涉及生物降解，扩散和吸附的复杂过程驱动的，该过程与沉积物表面积与废水量之比成正比。由于沉积物中微生物活性增强，生物标志物的由泥沙驱动的转化系数高于相应的生物膜介导速率。此外，大多数生物标记物的稳定性对下水道的自然pH变化不敏感，除了少数化合物（例如美沙酮，氯胺酮和扑热息痛）易受pH变化影响。总的来说，这项研究描述了具有沉积物的重力下水道中各种生物标志物的稳定性数据，这是基于废水的流行病学的新颖且长期缺失的信息，并提高了复杂下水道网络中反推定的可靠性。除少数化合物（如美沙酮，氯胺酮和扑热息痛）易受pH变化影响外，大多数生物标志物的稳定性对下水道的自然pH变化不敏感。总的来说，这项研究描述了具有沉积物的重力下水道中各种生物标志物的稳定性数据，这是基于废水的流行病学的新颖且长期缺失的信息，并提高了复杂下水道网络中反推定的可靠性。除少数化合物（如美沙酮，氯胺酮和扑热息痛）易受pH变化影响外，大多数生物标志物的稳定性对下水道的自然pH变化不敏感。总的来说，这项研究描绘了重力沉积物下水道中各种生物标志物的稳定性数据，这是基于废水的流行病学的新颖且长期缺失的信息，并提高了复杂下水道网络中反推定的可靠性。