Collaborative Research: Impacts of Metals on Disinfection Byproduct Precursor Formation in Bacteria

饮用水供应必须消毒，以保护人体健康。然而，消毒剂可以与系统中的有机物相互作用，导致形成对人类健康构成风险的副产品。了解消毒副产物的形成过程是水务公司和监管机构降低风险的关键需求。该项目通过调查微量金属如何影响配水系统中消毒副产物的形成来满足这一国家需求。潜在的假设是，在分配系统中的生物膜微生物暴露于重金属导致小的有机分子的释放。然后，这些分子可以通过与消毒剂的化学反应作为消毒副产物的构建块。该项目在环境微生物学和环境化学的界面上建立了俄克拉荷马州州立大学和锡拉丘兹大学之间的研究和教育伙伴关系。为小学生提供STEM教育推广计划，并为高中生提供暑期实习研究机会。这一努力将提高国家的科学素养，并提高STEM劳动力的能力，以满足社会对清洁和可持续用水的需求。消毒副产物是在水处理过程中有机物与消毒剂反应而形成的。控制消毒副产物形成的策略集中于在消毒之前去除它们的前体或在它们在水处理厂中形成之后去除消毒副产物。不幸的是，当分配系统中的生物膜释放的前体与残留的消毒剂反应时，消毒副产物继续在分配系统内形成。细菌的代谢过程和细胞调节对痕量金属的浓度高度敏感，这些浓度在分布系统中变化很大。本研究的总体目标是表征微量金属如何影响消毒副产物前体生产的生物膜条件下相关的加氯饮用水分配网络。中心假设是暴露于不同类型和浓度的痕量金属改变生物膜微生物的代谢途径，导致细菌释放的消毒副产物前体的组成和反应性发生变化。该项目的具体研究目标是：1）检查金属对细菌分离株消毒副产物形成潜力的影响，2）表征金属暴露对生物膜衍生消毒副产物前体的组成和反应性变化的影响，和3）通过转录组学确定细菌分离株和生物膜中消毒副产物形成潜力增加的潜在机制，蛋白质组学方法这项研究解决了知识和模型配方的差距，预测消毒副产品前体负载贡献的生物膜在氯胺分配系统。这项研究将提供一个更完整的了解，在金属形态和浓度的变化对消毒副产品形成潜力的影响，在全面的分配系统。该团队将招募代表性不足的少数民族学生到暑期研究岗位，以增加STEM领域的多样性，并通过安全饮用水研讨会向公众推广。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Potable water supplies must be disinfected to protect human health. However, disinfectants can interact with organic matter in the system to cause the formation of byproducts that pose risks to human health. Understanding the disinfection byproduct formation process is a critical need for water utilities and regulatory agencies to reduce risk. This project addresses this national need by investigating how trace metals influence disinfection byproduct formation in water distribution systems. The underlying hypothesis is that exposure of biofilm microbes in the distribution system to heavy metals results in the release of small organic molecules. These molecules can then serve as the building blocks of disinfection byproducts through chemical reaction with disinfectants. This project establishes a research and education partnership between Oklahoma State University and Syracuse University at the interface of environmental microbiology and environmental chemistry. A STEM educational outreach program for elementary school students and provide summer internship research opportunities for high school students. This effort will improve the scientific literacy of the Nation and increase the capability of the STEM workforce to meet societal needs for clean and sustainable water. Disinfection byproducts are formed upon reactions of organic matter with disinfectants during water treatment. Strategies to control disinfection byproduct formation focus on removing their precursors prior to disinfection or removing disinfection byproducts after they have formed in the water treatment plant. Unfortunately, disinfection byproducts continue to form within distribution systems when precursors released by biofilms in the distribution system react with residual disinfectant. Bacterial metabolic processes and cellular regulation are highly sensitive to concentrations of trace metals, which vary significantly in distribution systems. The overall goal of this research is to characterize how trace metals affect the production of disinfection byproduct precursors from biofilms under conditions relevant to chloraminated drinking water distribution networks. The central hypothesis is that exposure to varying types and concentrations of trace metals alters metabolic pathways in biofilm microorganisms, resulting in shifts in the composition and reactivity of disinfection byproduct precursors released by the bacteria. The specific research objectives of this project are to: 1) examine the influence of metals on disinfection byproduct formation potential from bacterial isolates, 2) characterize the effects of metal exposure on changes in the composition and reactivity of biofilm-derived disinfection byproduct precursors, and 3) determine the underlying mechanisms of increased disinfection byproduct formation potential in bacterial isolates and biofilms through transcriptomic and proteomic approaches. This research addresses gaps in knowledge and model formulations with regards to predicting disinfection byproduct precursor loadings contributed by biofilms in chloraminated distribution systems. This research will provide a more complete understanding of the impacts that changes in metal speciation and concentration have on disinfection byproduct formation potential in full-scale distribution systems. The team will recruit underrepresented minority students to summer research positions to increase the diversity of STEM fields and outreach to the public will take place through seminars on safe drinking water.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.