This study investigates the effect of chloramine residual on bacteria growth and regrowth and the relationship between heterotrophic plate counts (HPCs) and the concentration of chloramine residual in the Shanghai drinking water distribution system (DWDS). In this study, models to control HPCs in the water distribution system and consumer taps are also developed. Real-time ArcGIS was applied to show the distribution and changed results of the chloramine residual concentration in the pipe system by using these models. Residual regression analysis was used to get a reasonable range of the threshold values that allows the chloramine residual to efficiently inhibit bacteria growth in the Shanghai DWDS; the threshold values should be between 0.45 and 0.5 mg/L in pipe water and 0.2 and 0.25 mg/L in tap water. The low residual chloramine value (0.05 mg/L) of the Chinese drinking water quality standard may pose a potential health risk for microorganisms that should be improved. Disinfection by-products (DBPs) were detected, but no health risk was identified.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.watres.2014.10.041 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Optimization of a solid-phase extraction step by experimental design for application to SPE-GC-ECD analysis of four bromobenzoquinones and 2,4,6-tribromophenol in chlorinated seawater.
Heliyon
December 2024
Aix Marseille Univ, LCE, Marseille, France.
Bromobenzoquinones and 2,4,6-tribromophenol belong to disinfection or chlorination by-products than can be formed in bromide-rich waters during chlorination or chloramination. Due to their high toxicities, sensitive and cost-effective analytical methods are necessary to detect and quantify them in various environmental matrices. A determination method of 2,5-dibromo-1,4-benzoquinone, 2,6-dibromo-3,5-dimethyl-1,4-benzoquinone, 2,6-dibromo-3-chloro-5-methyl-1,4-benzoquinone, 2,3,5,6-tetrabromo-1,4-benzoquinone and, 2,4,6-tribromophenol was developed using solid-phase extraction and electron capture detector-gas chromatography separation and detection (SPE-GC-ECD).
View Article and Find Full Text PDFRegulated 1-2 Carbon Disinfection Byproducts do not Correlate with Cytotoxicity with Increasing Disinfectant Contact Time During Chlorination, Chlorination Followed by Chloramination or Granular Activated Carbon Followed by Chlorination.
Environ Sci Technol
November 2024
Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, California 94305, United States.
Article Synopsis
- Regulations use THM4 and HAA5 to measure health risks from disinfection byproducts (DBPs), assuming these metrics reflect toxicity levels.
- A study found that while increasing chlorine contact time raised THM4 and HAA5 levels, it actually decreased overall cytotoxicity, suggesting these metrics may mislead regulatory focus.
- Alternative methods, like granular activated carbon followed by chlorine, were shown to significantly reduce cytotoxicity, indicating the need for better toxicity-correlating metrics to enhance consumer safety in water distribution systems.
[Effect of low doses of active chlorine on commensal populations of intestinal bacteria in rats by oral ingestion].
Vopr Pitan
October 2024
Federal Research Centre of Nutrition, Biotechnology and Food Safety, 109240, Moscow, Russian Federation.
Article Synopsis
- Chlorine-containing substances are commonly used as disinfectants in the food industry, but their effects on residual amounts in the body and potential for antimicrobial resistance are not well understood.
- A study was conducted on male Wistar rats to investigate the effects of different doses of active chlorine on gut bacteria, body weight, and liver structure, using three concentrations: subinhibitory, threshold, and aggravated.
- Results showed that low doses of chlorine slightly reduced body weight gain and decreased certain bacteria levels, but no significant impact on antibiotic-resistant E. coli was found, although a trend toward increased resistance in Enterococci was noted.
An in-vitro evaluation of residual dentin retained after using novel enzymatic-based chemomechanical caries removal agents.
Sci Rep
August 2024
Department of Chemistry, College of Science, University of Baghdad, Baghdad, Iraq.
To assess the biochemical, mechanical and structural characteristics of retained dentin after applying three novel bromelain-contained chemomechanical caries removal (CMCR) formulations in comparison to the conventional excavation methods (hand and rotary) and a commercial papain-contained gel (Brix 3000). Seventy-two extracted permanent molars with natural occlusal carious lesions (score > 4 following the International Caries Detection and Assessment System (ICDAS-II)) were randomly allocated into six groups (n = 12) according to the excavation methods: hand excavation, rotary excavation, Brix 3000, bromelain-contained gel (F1), bromelain-chloramine-T (F2), and bromelain-chlorhexidine gel (F3). The superficial and deeper layers of residual dentin were examined by Raman microspectroscopy and Vickers microhardness, while the surface morphology was assessed by the scanning electron microscope (SEM).
View Article and Find Full Text PDFSource-to-tap investigation of the occurrence of nontuberculous mycobacteria in a full-scale chloraminated drinking water system.
Appl Environ Microbiol
September 2024
Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA.
Article Synopsis
- Nontuberculous mycobacteria (NTM) in drinking water pose a significant public health risk, but understanding the factors affecting their occurrence is limited, impacting infection prevention efforts.
- The study collected water samples monthly over a year to evaluate the impact of factors like season, water treatment, distribution, and stagnation on NTM presence in a chloraminated drinking water system.
- Findings indicated that summer first-draw water samples had the highest NTM densities, flushing effectively reduced NTM levels, and higher occurrences were linked to older building plumbing systems, highlighting the importance of water management practices.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!