The Impact of Environmental Variables on Faecal Indicator Bacteria in the Betna River Basin, Bangladesh

Abstract

Environmental variables influence Faecal Indicator Bacteria (FIB) in surface water. Understanding that influence is important, because presence of FIB, which are an indication of faecal contamination, means that harmful pathogens could be present that could also be influenced by environmental variables. Although some recent studies have focused on this topic, most of this work has been conducted in developed countries. Similar studies in developing countries and in a (sub)tropical climate are lacking. In this study we assess the influence of environmental variables on fluctuations in FIB concentrations of the Betna River in southwest Bangladesh that floods almost every year. Monthly water samples from five locations along Betna River were tested for FIB (E. coli and enterococci) in 2014-2015. A linear regression model was developed to assess the effect of the environmental variables on FIB concentrations. The study revealed increased FIB concentrations during wet weather conditions. Precipitation and water temperature were positively correlated with FIB concentrations. Water temperature was positively correlated, because the warm May to September period coincides with frequent precipitation. Precipitation increases manure release from land to surface water. The regression model explains nearly half of the variability in FIB concentrations (R 2 of 0.46 for E. coli and 0.48 for enterococci). This study indicates that increased precipitation combined with higher water temperature, as is expected in this region with climate change, likely increases FIB concentrations. Waterborne pathogens are expected to respond similarly to these environmental changes, indicating that disease outbreaks could well become more frequent and severe.

Microbiome patterns reveal the transmission of pathogenic bacteria in hilsa fish (Tenualosa ilisha) marketed for human consumption in Bangladesh

“…; Islam et al . ). Among these bacteria, V. cholera is the most abundant and widely detected (>25%) in various types of water sources (Rafique et al .…”

“…In Dhaka, water from rivers and households is reported to have an abundance of coliforms and pathogenic bacteria such as V. cholerae, E. coli, K. pneumoniae and Aeromonas spp. (Acharjee et al 2011;Islam et al 2017). Among these bacteria, V. cholera is the most abundant and widely detected (>25%) in various types of water sources (Rafique et al 2016;Rashid et al 2017).…”

Modelling the Present and Future Water Level and Discharge of the Tidal Betna River

“…Land use is dominated by paddy cultivation and shrimp culture. About 8% of the total area is homesteads and settlements, about 10% is water bodies, 61% is agriculture and the remainder is wetlands used for aquaculture or integrated paddy shrimp culture [3,17].…”

The evaluation of ecological status in Tunca (Tundzha) River (Turkish Thrace) based on environmental conditions and bacterial features

“…The negative conditions from both continental and atmospheric environments can instantly reflected by these ecosystems (Çolakoğlu & Çakır, 2004;Bernot & Dodds, 2005). Although the studies on composition and abundance of microorganisms in biosphere have a lot of significance, in recent years it was also the investigations of bacteria in aquatic ecosystems have got an increasing significance (Jamieson et al, 2003;Hunt & Sarıhan, 2004;Agbogu et al, 2006;Niemi & Raateland, 2007;Sabae & Rabeh, 2007;Mishra & Batt, 2008;Suneela et al, 2008;Mishra et al, 2009Mishra et al, , 2010Saha et al, 2009;Bulut et al, 2010;Kumar et al, 2010;Venkatesharaju et al, 2010;Nguyen et al, 2016;Islam et al, 2017;Alves et al, 2018;Loucif et al, 2020). A lot of study is also carried out in our country.…”