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This study was conducted to assess potential human health risks presented by pathogenic bacteria in a protected multi-use lake-reservoir (Lake Ma Vallée) located in west of Kinshasa, Democratic Republic of Congo (DRC). Water and surface sediments from several points of the Lake were collected during summer. Microbial analysis was performed for Escherichia coli, Enterococcus (ENT), Pseudomonas species and heterotrophic plate counts. PCR amplification was performed for the confirmation of E. coli, ENT, Pseudomonas spp. and Pseudomonas aeruginosa isolated from samples. The results reveal low concentration of bacteria in water column of the lake, the bacterial quantification results observed in this study for the water column were below the recommended limits, according to WHO and the European Directive 2006/7/CE, for bathing water. However, high concentration of bacteria was observed in the sediment samples; the values of 2.65 × 10(3), 6.35 × 10(3), 3.27 × 10(3) and 3.60 × 10(8) CFU g(-1) of dry sediment for E. coli, ENT, Pseudomonas spp. and heterotrophic plate counts, respectively. The results of this study indicate that sediments of the Lake Ma Vallée can constitute a reservoir of pathogenic microorganisms which can persist in the lake. Possible resuspension of faecal indicator bacteria and pathogens would affect water quality and may increase health risks to the population during recreational activities. Our results indicate that the microbial sediment analysis provides complementary and important information for assessing sanitary quality of surface water under tropical conditions.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1Microbiological and physicochemical characterization of water and 1 sediment of an urban river: N'Djili River, Kinshasa, Democratic , 1982; An et al., 2002; Haller et al., 2009a (Ndiaye, 2009; Gemmell and Schmidt, 2012). These studies 69 demonstrated that pathogens contained in the wastewater used for irrigation can be transferred 70 to the raw vegetables and fresh produces. Grimes 71The N'djili River is one of tributaries of Congo River that drain the capital city of 72Kinshasa. Due to its position in the city, the river is used for many activities including water Materials and methods 86 Study site and sampling procedure 87The source of N'djili River is located in the province of Bas-Congo. The river flows contamination. These activities include the industrial effluent discharge (IED), the presence of 95 uncontrolled landfills (PUL) and urban agricultural and storm runoff (UAS) (Fig. 1). Water 96 samples (300 mL in sterile plastic bottles) were triplicated from 3 selected areas described 97 above; EE1-EE3 from IED, EE4-EE6 from PUL and EE7-EE9 from UAS. Surface sediments Water and sediment physicochemical analysis 107Physicochemical parameters of water including temperature (°C), pH and electrical 108 conductivity (EC) were determined in the sampling sites using a Multi 350i (WTW, 109 Germany). The grain size distribution was measured using a particle size analyzer Coulter ® The results were expressed as colony forming units per 100 mL of water (CFU 100mL -1 ) or 134 100 g of fresh sediments (CFU 100g -1 ). The reproducibility of the whole experimental PCR assays for detection of general FIB, E. faecalis and human bacteroides 139The genomic profiles of general origin of E. coli and ENT were performed by PCR 140 assays (presence/absence) using specific primers and operational conditions as summarized in The PCR assays for human E. faecalis and for the human-specific bacteroides were 149 performed on the total DNA extracted from sediment samples and selected colonies which 155The purified DNA was kept at -20 °C until used. The human-specific bacteroides were 156 analyzed by PCR assays (presence/absence) using specific primers and operational conditions 157 according to published methods as summarized in Table 2 The FIB quantification was performed both in water and sediments sampled from the 202 same GPS locations. The results are presented in Table 3. For the water samples, the FIB studies (Crabill et al., 1999; Alm et al., 2003; Craig et al., 2004; Lee et al., 2006 Guidelines. Mercury (Hg) analysis in sediment samples 293The results o...

The original version of this article unfortunately contained a mistake. The publication year and volume for reference Varga, L. was incorrect. The correct reference is presented below. Varga, L. (2011). Bacteriological quality of bottled natural mineral waters commercialized in Hungary. Food Control, 22, 591-595.

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