Collaborative Research: Role of Organic Matter Source on the Photochemical Fate of Pharmaceutical Compounds

PI： Allison MacKay / Yu-Ping Chin / Charles Sharpless提案编号： 1133600 / 1133094 /1132207鉴于用于医疗条件的化学品种类繁多，以及促进其释放到水生系统的各种废水管理计划，评估人类药物化合物对环境的影响是一项艰巨的任务。 先前的研究表明，光降解反应是环境中药物化合物的重要衰减过程。 药物对光化学反应的敏感性将受到这些化合物与流出物有机物（EfOM）共同释放的影响。 预期EfOM相对于充分研究的天然有机物质（NOM）源具有不同的光反应性，大概是因为与NOM相比，其预期的较低芳香族含量和较低颜色。PI假设药物化合物光降解将随着天然通道流中废水流出物比例的增加而改变，因为EfOM的存在增加，拟议研究的最终目标是确定与药物化合物的增强环境光降解速率相关的关键环境系统特征。 他们提出了三个主要的研究活动来评估他们的假设。 (1)：现场测量的环境退化率和途径，将获得代表性的废水排放情景？森林覆盖的新英格兰流域（康乃狄克州庞培劳河）、中西部农业流域（俄亥俄州小迈阿密河东支流）以及带有混合污水排放口的城市河流（康乃狄克州帕克河）。 将在污水排放的下游获得流量调整样本，以测量不同季节性EFOM-NOM比率的伪一阶环境退化率。 通过比较白天和夜间的观测结果，将光解损失与其他损失区分开来。 支持实验室降解研究将解决有机物（OM）类型的光化学途径的贡献。 (2)：有机物将与现场隔离，包括直接与废水隔离。 将使用XAD-8树脂和切向流超滤的分离方法，以与地球化学方法保持一致。 将对分离株的生化成分（热化学分解）以及光学和结构特性（UV-Vis、荧光、固态13 C NMR）进行表征。 (3)：将获得OM分离物的单线态氧、过氧化氢和激发三重态OM的量子产率，并将其与OM特性相关联（任务2）。 总之，任务2和任务3的结果将产生关键的见解，解释光降解速率常数（任务1）之间的网站和季节内的差异，污水的贡献在每个网站的变化。这项研究将是第一个研究药物化合物在新英格兰和中西部河流的命运，扩大以前的命运研究从干旱系统。他们将建立一个关于药物化合物命运的环境系统驱动因素的重要知识体系，这将有助于制定有关监管，补救和/或？绿色？药物化合物的设计。 他们将与Pomperaug River Watershed Coalition和East Fork Watershed Cooperative密切合作，通过半年一次的项目进展报告，让公民参与尖端科学，让水管理人员和社区成员参与水质采样，并组织跨学科圆桌会议，汇集环境科学家和工程师，监管机构，与生态学家和药理学家讨论环境中药物化合物的环境管理。PI将通过科学发现的过程指导研究生和本科生研究人员？实验设计、手稿准备和国家专业学会报告。 PI将继续保持他们从科学和工程领域代表性不足的群体中吸引学生研究人员的记录。 学生将有一个独特的机会与指导PI团队合作，该团队具有工程（PI MacKay），地球化学（PI Chin），光化学（PI Sharpless）和系统生态学（合作者Nietch）的专业知识，为自己的项目提供广泛的背景。

PIs: Allison MacKay / Yu-Ping Chin / Charles SharplessProposal Numbers: 1133600 / 1133094 / 1132207Evaluating the impacts of human pharmaceutical compounds in the environment is a daunting task, given the wide variety of chemicals administered for medical conditions and the various wastewater management schemes that facilitate their release to aquatic systems. Prior studies suggest photodegradation reactions to be important attenuation processes for pharmaceutical compounds in the environment. The susceptibility of pharmaceuticals to photochemical reactions will be impacted by the co-release of these compounds with effluent organic matter (EfOM). EfOM is expected to have differing photoreactivity, relative to well-studied natural organic matter (NOM) sources, presumably because of its anticipated lower aromatic content and lower color, compared to NOM. The PIs hypothesize that pharmaceutical compound photodegradation will be altered with increasing proportion of wastewater effluent in natural channel flow because of the increased presence of EfOM, relative to NOM. The ultimate goal of the proposed research is to identify key environmental system characteristics that are associated with enhanced environmental photodegradation rates of pharmaceutical compounds. They propose three major research activities to evaluate their hypothesis. (1): Field measurements of environmental degradation rates and pathways will be obtained for representative wastewater discharge scenarios ? forested New England watershed (Pomperaug River, CT), agricultural Midwestern watershed (East Fork of the Little Miami River, OH), and an urban stream with combined sewer outfalls (Park River, CT). Flow-adjusted samples will be obtained downstream of the effluent discharge to measure pseudo-first order environmental degradation rates with differing seasonal EfOM-to-NOM ratios. Photolysis losses will be differentiated from other losses by comparing daytime and nighttime observations. Supporting lab degradation studies will resolve contributions of organic matter (OM) type to photochemical pathways. (2): OM will be isolated from the field sites, including from effluent streams directly. Isolation methods of XAD-8 resin and tangential flow ultrafiltration will be used for consistency with geochemistry methods. Isolates will be characterized for their biochemical constituents (thermochemolysis), and for optical and structural properties (UV-Vis, fluorescence, solid-state 13C NMR). (3): Quantum yields of singlet oxygen, hydrogen peroxide and excited triplet-state OM will be obtained for OM isolates and correlated to OM characteristics (Task 2). Together, the results of Tasks 2 and 3 will yield critical insights for interpreting differences in photodegradation rate constants (Task 1) among the sites and within seasons, as effluent contributions change at each site. This study will be the first to examine the fate of pharmaceutical compounds in New England and Midwestern rivers, expanding on prior fate studies from arid systems. They will establish an important body of knowledge about environmental system drivers of pharmaceutical compound fates that will contribute to robust science-based decisions about regulation, remediation, and/or ?green? design for pharmaceutical compounds. They will work closely with the Pomperaug River Watershed Coalition and the East Fork Watershed Cooperative to engage citizens in cutting-edge science through semi-annual project progress presentations, to involve water managers and community members in water quality sampling, and to organize a cross-disciplinary Roundtable to bring together environmental scientists and engineers, regulators, with ecologists and pharmacologists to discuss environmental management of pharmaceutical compounds in the environment. The PIs will mentor graduate and undergraduate researchers through the process of scientific discovery ? experimental design, manuscript preparation and national professional society presentations. The PIs will continue their record of engaging student researchers from groups underrepresented in the sciences and engineering. Students will have a unique opportunity to work with a guiding PI team with expertise in engineering (PI MacKay), geochemistry (PI Chin), photochemistry (PI Sharpless) and systems ecology (Collaborator Nietch), providing broad context for their own projects.