CAREER: Development of a Novel Approach for the Identification of Toxic Byproducts and their Precursors in Oxidative Drinking Water Treatment

化学氧化剂如氯、氯胺、臭氧和过氧化氢被广泛用于水处理中作为消毒剂以灭活病原体和作为反应物以减少饮用水源中的有机污染物。这些化学氧化剂还可以与有机污染物和溶解的有机物（DOM）反应，产生副产物，由于其潜在的毒性，这些副产物可能对人类健康产生不利影响。目前，已在处理过的饮用水中检测到数百种副产品。然而，只有有限数量的这些副产物进行了毒性评估，因为目前用于评估其毒性的方案依赖于缓慢且低效的化学品逐个化学品评估方法。这个CAREER项目的首要目标是开发一种新的方法来识别用化学氧化剂处理的饮用水中的有毒副产品及其前体。这种新的方法，反应性导向分析（RDA），建立在药物开发和化学风险评估中开创的技术和协议的基础上，以识别用化学氧化剂处理的饮用水样品中具有相似毒性机制的所有副产物。该项目的成功完成将通过产生新的基础知识来了解，控制和减轻化学氧化剂处理的饮用水中有毒副产品及其前体的形成，从而造福社会。通过学生教育和培训，包括指导约翰霍普金斯大学的一名研究生，将进一步造福社会。水处理中使用的化学氧化剂与饮用水源中的有机污染物和溶解性有机物（DOM）反应，产生各种各样的副产物。然而，对饮用水副产品毒性的全面评估仍然是难以捉摸的。这个职业生涯项目将解决这一关键的知识差距。为了推进这一目标，主要研究者（PI）提议开发和应用一种新型方法来检测有毒副产品，称为反应性指导分析（RDA）。这种创新的方法利用了药物开发和化学风险评估中开创的分析和协议，以识别经处理的饮用水中的有毒有机亲电体（已知毒物中最大的一类），并阐明其前体。拟议研究的具体目标是：1）开发一种新的基于微珠的RDA检测方法，用于检测复杂水性基质中的有机亲电体，2）研究由酚DOM模型化合物与化学氧化剂反应产生的有机亲电体的形成和反应机理，以及3）研究由DOM分离物反应产生的有机亲电体的形成，处理过的废水和含有化学氧化剂的地表水。该项目的成功完成有可能产生变革性影响，通过产生基础知识，推动开发和实施一个新的框架，用于识别有毒副产品及其前体，可用于最大限度地减少和减轻其在饮用水处理系统中的形成。为了实现这个职业项目的教育和培训目标，PI将利用他与食品项目（TFP）的持续合作来开发和实施一个课外计划（EnviroSense），该计划将使初中和高中学生接触到水质传感器的设计和应用。此外，PI计划开发两门新课程，包括关于水质传感器的本科生实验室课程和关于水质评估和监测的研究生课程。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Chemical oxidants such as chlorine, chloramine, ozone, and hydrogen peroxide are widely used in water treatment as disinfectants to deactivate pathogens and as reactants to abate organic contaminants in drinking water sources. These chemical oxidants can also react with organic contaminants and dissolved organic matter (DOM) to generate byproducts which can adversely impact human health due to their potential toxicity. Currently, hundreds of byproducts have been detected in treated drinking water. However, only a limited number of these byproducts have been evaluated for toxicity as the current protocols used to assess their toxicity rely on a slow and inefficient chemical-by-chemical evaluation approach. The overarching goal of this CAREER project is to develop a novel approach to identify toxic byproducts and their precursors in drinking water treated with chemical oxidants. This novel approach, reactivity-directed analysis (RDA), builds upon techniques and protocols pioneered in drug development and chemical risk assessment to identify all byproducts with simar mechanisms of toxicity in a sample of drinking water treated with chemical oxidants. The successful completion of this project will benefit society through the generation of new fundamental knowledge to understand, control, and mitigate the formation of toxic byproducts and their precursors in drinking water treated with chemical oxidants. Further benefits to society will be achieved through student education and training including the mentoring of a graduate student at Johns Hopkins University. Chemical oxidants used in water treatment react with organic contaminants and dissolved organic matter (DOM) in drinking water sources to generate a large variety of byproducts. However, a comprehensive assessment of the toxicity of drinking water byproducts has remained elusive. This CAREER project will address this critical knowledge gap. To advance this goal, the Principal Investigator (PI) proposes to develop and apply a novel approach to detect toxic byproducts, called reactivity-directed analysis (RDA). This innovative approach leverages assays and protocols pioneered in drug development and chemical risk assessment to identify toxic organic electrophiles (the largest class of known toxicants) in treated drinking water and elucidate their precursors. The specific objectives of the proposed research are to: 1) Develop a novel microbead-based RDA assay for the detection of organic electrophiles in complex aqueous matrices, 2) Investigate the formation and reaction mechanisms of organic electrophiles produced from the reaction of phenolic DOM model compounds with chemical oxidants, and 3) Investigate the formation of organic electrophiles produced from the reactions of DOM isolates, treated wastewater, and surface water with chemical oxidants. The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge to advance the development and implementation of a new framework for identifying toxic byproducts and their precursors that could be used to minimize and mitigate their formations in drinking water treatment systems. To implement the educational and training goals of this CAREER project, the PI will leverage his ongoing collaboration with The Food Project (TFP) to develop and implement an afterschool program (EnviroSense) that will expose middle and high-school students to the design and applications of water quality sensors. In addition, the PI plans to develop two new courses including an undergraduate lab course on water quality sensors and a graduate course on water quality assessment and monitoring.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.