Flint/Detroit Simulated Glass Water Heater Microcosms

A benchtop study was conducted using water from Flint and Detroit Michigan to better understand the Legionnaires Disease outbreaks caused from the change in source water in 2014. Thirty six 120 mL stained glass water heater microcosms contained PEX or copper pipe coupons aged for 8.5 years with biofilms confirmed to contain Legionella pneumophila. 50 percent water changes were conducted twice a week for 1 year with water sourced from Flint and Detroit to twenty-four and twelve jars respectively. In triplicate, Detroit Jars were split into a control group and a group dosed with ferric pyrophosphate, and Flint Jars split into control, ferric pyrophosphate, ferric chloride, and ferrous chloride. See Copper Pipe, Lack of Corrosion Control, and Very Low pH May Have Influenced the Trajectory of the Flint Legionnaires Disease Outbreak by Martin et al., 2022 and chapter 4 of Philippe Mena-Aguilar, 2021 for a more thorough description of methods.本研究采用密歇根州弗林特与底特律的水源开展台式实验，旨在深入解析2014年因水源变更引发的军团菌病（Legionnaires Disease）暴发事件。实验共设置36个120mL带彩色玻璃的热水器微型生态培养体系，内置经8.5年老化的交联聚乙烯（PEX）或铜管挂片，其生物膜经证实含有嗜肺军团菌（Legionella pneumophila）。在为期1年的实验周期内，每周更换两次50%体积的实验用水，分别使用弗林特水源水与底特律水源水喂养24个与12个微型生态容器。在设置三次平行重复的前提下，底特律组被划分为对照组与焦磷酸铁（ferric pyrophosphate）给药组；弗林特组则划分为对照组、焦磷酸铁给药组、氯化铁（ferric chloride）组与氯化亚铁（ferrous chloride）组。如需了解实验方法的详细描述，可参阅Martin等人2022年发表的《铜管、腐蚀控制缺失与极低pH值或影响弗林特军团菌病暴发进程》一文，以及Philippe Mena-Aguilar 2021年专著的第4章。