Origin and spatial–temporal distribution of faecal bacteria in a bay of Lake Geneva, Switzerland

Abstract

The origin and distribution of microbial contamination in Lake Geneva's most polluted bay were assessed using faecal indicator bacteria (FIB). The lake is used as drinking water, for recreation and fishing. During 1 year, water samples were taken at 23 points in the bay and three contamination sources: a wastewater treatment plant (WWTP), a river and a storm water outlet. Analyses included Escherichia coli, enterococci (ENT), total coliforms (TC), and heterotrophic plate counts (HPC). E. coli input flux rates from the WWTP can reach 2.5 × 10 10 CFU/s; those from the river are one to three orders of magnitude lower. Different pathogenic Salmonella serotypes were identified in water from these (1) the WWTP outlet at 30 m depth impacts near-surface water quality during holomixis in winter; (2) when the lake is stratified, the effluent water is generally trapped below the thermocline; (3) during major floods, upwelling across the thermocline may occur; (4) the river permanently contributes to contamination, mainly near the river mouth and during floods, when the storm water outlet contributes additionally; (5) the lowest FIB levels in the nearsurface water occur during low-flow periods in the bathing season.

Occurrence and fate of micropollutants in the Vidy Bay of Lake Geneva, Switzerland. Part I: Priority list for environmental risk assessment of pharmaceuticals

“…Effluent is discharged at the WWTP Vidy into the bay at 30 m depth, 700 m from the shore. Raw drinking water is pumped at St. Sulpice drinking water plant from 45 m depth (modified and reproduced from Poté et al[30],Figure 1, with kind permission from Springer Science þ Business Media). WWTP ¼ wastewater treatment plant.…”

Vertical and horizontal composition of fecal pollution indicator bacteria in lotic and lentic ecosystems at Turkish Thrace

“…Both physicochemical properties and qualitative/quantitative distributions of organisms have been used to determine the quality of inland waters. The determination of fecal indicator bacterial distributions is of great importance in the studies of aquatic ecosystems (1,2,3,4), especially the contents of coliform bacteria and E. coli bacteria which are known as indicator microorganisms. Also, some environmental parameters can be affected as a result of their distributions (5,6,7,8,9), as, physicochemical features can change vertically and horizontally in the water and the bacterial distribution can be affected by the changing environment.…”

“…Cardak and Altug (2) reported that the highest bacteria count in the bottom were caused by deep discharges to the water from domestic or agricultural activities. Furthermore, Pote et al (4) discussed that the high bacterial accounts at the bottom were related to increased temperature, biological activity and predation by bacterivorous organisms, as well as UV radiation.…”

Long-term and short-term variations of Escherichia coli population structure in tropical coastal waters

“…As the average Klang River flowrate is 25 m 3 s -1 (Lai 1983), E. coli loading at Klang estuary was estimated at 5.8 9 10 9 cfu s -1 . The high loading rate is reflective of a severely polluted aquatic system (Poté et al 2009). …”