Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4485184 | Water Research | 2005 | 11 Pages |
Flow cytometry (FCM), combined with staining using two fluorochromes (propidium iodide, PI, or SYBR Green II RNA gel stain, SYBR-II), was used to assess nucleic acid injuries to chlorinated drinking water bacteria. Highly fluorescent SYBR-II-stained bacteria were converted to bacteria with low fluorescence after chlorination. PI staining of bacteria exposed to different doses of chlorine showed membrane permeabilisation ([Cl2]<0.2 mg L−1) and nucleic acid damage at higher doses ([Cl2]>0.3 mg L−1). Above a threshold dose (between 1.5 and 3 mg Cl2 L−1), nucleic acids appeared severely damaged and incapable of being stained by PI or SYBR-II. These results constitute evidence that FCM is a promising tool for assessing drinking water bacteria injuries and for controlling chlorine disinfection efficiency much more rapidly than the standard sensitive but time-consuming heterotrophic plate count method.