Survival, transport and dissemination of Escherichia coli and enterococcci in a fissured environment. Study of a flood in a karstic aquifer

Abstract

In fissured aquifers, hydrodynamic phenomena combined with a network of permeable fissures imparts varying degrees of vulnerability depending on the type of contaminant. The study presented here examines the impact on a karst aquifer of a river which receives effluents from a sewage treatment plant just upstream from the point of recharge. This recharge constitutes a source of bacteriological and chemical pollution. The aquifer is accessible by boreholes at discrete points, facilitating investigation of the evolution of three of the contaminants characteristic of treatment station effluents, NH4+ and two biological contaminants with different survival capacities. The study was undertaken both under normal climatic conditions and during a flood occurring after a long dry period. The rate of infiltration, of subsurface transport, and of dissemination of contaminants into a zone usually protected from contamination was recorded. The results confirm the vulnerability of fissured aquifers to contamination.

Water quality associated public health risk in Bo, Sierra Leone

“…The main concern of biological contamination is waterborne pathogens, such as bacteria, viruses, protozoa, and helminthic parasites, which pose widespread risks to health when drinking water that is untreated or insufficiently treated (Savichtcheva and Okabe 2006). Tests for the presence of Escherichia coli and fecal coliform are used as indicators of bacteriological contamination (Edge and Hill 2007;Cabral 2010;Foppen and Schijven 2005;Howard et al 2003;Muniesa et al 2006;Personne et al 1998;Powell et al 2003;Schets et al 2005;van Lieverloo et al 2007;Kozuskanich et al 2011;Savichtcheva and Okabe 2006). In addition to microbiological contamination, chemical substances in water, such as fluoride, nitrates, arsenic, and lead and other heavy metals, can also have adverse health effects (Prüss-Üstün et al 2008;Reimann and Banks 2004;Islam et al 2000).…”

Transport of Algal Cells in Hyporheic Sediments of the River Elbe (Germany)

“…However, little information is available about the subsurface transport behaviour of algal cells. Previous research on interstitial transport of particles has focused on disease-causing bacteria and viruses (BALES et al, 1997;PERSONNÉ et al, 1998;SIMONI et al, 1998; CHEN and STRE-VETT, 2001) and on bacteria used for bioremediation and degradation of groundwater contaminants (HARVEY and GARABEDIAN, 1991;CAMESANO and LOGAN, 1998;FULLER et al, 2000). The transport characteristics of groundwater protozoa in contaminated aquifer systems were described by few studies (SINCLAIR et al, 1993;HARVEY et al, 1995;HARVEY et al, 1997).…”

Use of particulate surrogates for assessing microbial mobility in subsurface ecosystems

“…This may cause critical processes such as preferential flow, which permit contaminants to by-pass deposits that may otherwise attenuate them (Foppen and Schijven 2006). Such processes have been demonstrated to be fundamental in influencing groundwater quality in highly heterogeneous karst aquifers, as indicated by the rapid occurrence of coliforms at karst springs following rainfall events in many studies (Personné et al 1998;Auckenthaler et al 2002;Shevenell and McCarthy 2002;Pronk et al 2006).…”