Seasonal variability of faecal indicator bacteria numbers and die-off rates in the Red River basin, North Viet Nam

• DOI: 10.1038/srep21644
• Publication Date: 2016-02-12T11:05:20Z
• Authors: Huong Thi Mai Nguyen; Quynh Thi Phuong Le; J. Garnier; J.-L. Janeau; E. Rochelle-Newall
• Keywords: 550; Economics; Health, Toxicology and Mutagenesis; Veterinary medicine; 02 engineering and technology; Biochemistry; Gene; Occurrence and Health Effects of Drinking Water Disinfection By-Products; Feces; Endocrinology; Sociology; [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases; Viet nam; Water Science and Technology; Dynamics and Pathogenesis of Cholera Bacteria; Waterborne Disease Outbreaks and Pathogen Transport; Enteric bacteria; Geography; Statistics; Life Sciences; Economy; 6. Clean water; FOS: Sociology; Vietnam; Physical Sciences; [SDV.MHEP.MI] Life Sciences [q-bio]/Human health and pathology/Infectious diseases; Medicine; Seasons; Water Microbiology; Environmental Monitoring; Cartography; 570; Drainage basin; Population; 0207 environmental engineering; Article; Environmental science; Significant difference; Enterobacteriaceae; Rivers; Biochemistry, Genetics and Molecular Biology; Escherichia coli; FOS: Mathematics; Genetics; Humans; Biology; Demography; Bacteria; Water Pollution; FOS: Biological sciences; Environmental Science; Microbial Source Tracking; Animal science; Mathematics

AbstractThe Red River is the second largest river in Viet Nam and constitutes the main water source for a large percentage of the population of North Viet Nam. Here we present the results of an annual survey of Escherichia coli (EC) and Total Coliforms (TC) in the Red River basin, North Viet Nam. The objective of this work was to obtain information on faecal indicator bacteria (FIB) numbers over an annual cycle and, secondly, to determine the die-off rates of these bacterial indicators. Monthly observations at 10 stations from July 2013–June 2014 showed that TC and EC reached as high as 39100 cfu (colony forming units) 100 ml−1 and 15300 colonies 100 ml−1, respectively. We observed a significant seasonal difference for TC (p < 0.05) with numbers being higher during the wet season. In contrast, no significant seasonal difference was found for EC. The FIB die-off rates ranged from 0.01 d−1 to a maximum of 1.13 d−1 for EC and from 0.17 d−1 to 1.33 d−1 for TC. Die-off rates were significantly higher for free bacteria than for total (free + particle attached) bacteria, suggesting that particle attachment provided a certain level of protection to FIB in this system.