The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Walter Wildi - One of the best experts on this subject based on the ideXlab platform.
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distribution and survival of faecal indicator bacteria in the sediments of the bay of vidy lake geneva switzerland
Ecological Indicators, 2009Co-Authors: Laurence Haller, John Pote, Jeanluc Loizeau, Walter WildiAbstract:Abstract The purpose of this study was to determine the concentrations and the horizontal distribution of faecal indicator bacteria (FIB) including Escherichia coli and Enterococcus sp. in the bottom sediments of the Bay of Vidy, City of Lausanne, Switzerland. A vertical distribution of FIB in sediments near the municipal wastewater treatment plant (WWTP) Outlet was evaluated and their persistence in those sediments was monitored for a period of 90 days. High FIB levels were measured in the sediments sampled near the WWTP Outlet Pipe and the mouth of the Chamberonne River, at concentrations ranging between 105 and 107 CFU 100 g−1. FIB levels at 10 cm depth in the sediments near the WWTP Outlet Pipe ranged between 104 and 105 CFU 100 g−1, and were still detected in the top 6 cm after 90 days. Results of this study indicate that freshwater sediments of the Bay of Vidy constitute a reservoir of faecal indicator bacteria, which can persist in certain areas of the bay. Possible resuspension of FIB and pathogens may affect water quality and may increase health risks to sensitive populations during recreational activities. FIB survival in sediments for long periods is of considerable significance for the understanding of microbial pollution in water and for the management of risk at specific recreational coastal sites.
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effects of a sewage treatment plant Outlet Pipe extension on the distribution of contaminants in the sediments of the bay of vidy lake geneva switzerland
Bioresource Technology, 2008Co-Authors: John Pote, Andrea G Bravo, Laurence Haller, Jeanluc Loizeau, Vincent Sastre, Walter WildiAbstract:In 2001, the municipality of Lausanne extended the Outlet Pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the Outlet Pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the Pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement.
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characterizing water circulation and contaminant transport in lake geneva using bacteriophage tracer experiments and limnological methods
Environmental Science & Technology, 2007Co-Authors: Nicola Goldscheider, John Pote, Laurence Haller, Walter Wildi, Jakob ZopfiAbstract:Multi-tracer tests with three types of marine bacteriophages (H4/4, H6/1, and H40/1), together with various limnological methods, including physicochemical depth profiling, surface drifters, deep current measurements, and fecal indicator bacteria analyses, have been applied to characterize water circulation and pathogen transport in the Bay of Vidy (Lake Geneva, Switzerland). The experimental program was carried out twice, first in November 2005, when the lake was stratified, and a second time during holomixis in February 2006. The bacteriophages were injected at three points at different depths, where contaminated waters enter the lake, including the Outlet Pipe of a wastewater treatment plant, a river, and a stormwater Outlet. Thereafter, water samples were collected in the lake at 2 m depth during a 48 h sampling campaign. The results demonstrate that (i) contaminated river water spreads rapidly in the bay; (ii) a well-developed thermocline is highly effective in preventing contamination from the depth...
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the impact of a sewage treatment plant s effluent on sediment quality in a small bay in lake geneva switzerland france part 1 spatial distribution of contaminants and the potential for biological impacts
Lakes and Reservoirs: Research and Management, 2004Co-Authors: Michel Pardos, Christophe Benninghoff, Luis Felippe De Alencastro, Walter WildiAbstract:The purpose of this study was to assess the quality of bottom sediment collected in the Bay of Vidy (Lake Geneva, Switzerland) which receives sewage treatment plant discharges from the city of Lausanne and its surroundings. Thirty-eight sediment samples were taken, forming a dense network. Samples of that portion of the sediment that has accumulated since phosphorus removal (via iron precipitation) was instituted at the plant in 1971 were analysed for heavy metals, nutrients and organic micropollutants and subjected to Microtox toxicity evaluation (organic extract). The distribution patterns of contaminants, as well as principal components analysis, demonstrated that the sewage treatment plant's effluent is the main source of local sediment contamination. This was not supported by the Microtox results. In close proximity to the Outlet Pipe of the sewage treatment plant, contaminants showed very high median concentrations for virtually all the parameters measured, at levels above those believed to elicit biological responses. A major environmental impact is clearly occurring in this coastal region of the lake and remediation of this situation is believed to be important in order to protect the Lake Geneva ecosystem.
John Pote - One of the best experts on this subject based on the ideXlab platform.
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distribution of mercury and organic matter in particle size classes in sediments contaminated by a waste water treatment plant vidy bay lake geneva switzerland
Journal of Environmental Monitoring, 2011Co-Authors: Andrea G Bravo, Sylvain Bouchet, David Amouroux, John Pote, Janusz DominikAbstract:In Lake Geneva, Switzerland, the most Hg-contaminated sediments have been found in the Vidy Bay where high Hg contents largely exceeds the background levels of Lake Geneva sediments. This contamination has been attributed to the discharge of a waste water treatment plant (WWTP). Total Hg (THg) and monomethylmercury (MMHg) were determined in bulk sediment and in three different grain size fractions (i: clay and silt, ii: fine-coarse sand, iii: and very coarse sand and gravel) collected close to the Outlet Pipe of a WWTP in order to verify whether the standardized procedures of sediment treatment is adequate for this setting and, by extension, for similar contaminated sites. THg was homogeneously distributed in the different grain size fractions and was correlated to organic matter content (R2 = 0.6). MMHg was homogeneously distributed in the two finer grain fractions (Φ < 0.063 mm; 0.063 mm < Φ <1 mm). The results of this study suggested that the analysis of the bulk sediment seems to be more appropriate for the assessment of the content and spatial distribution of Hg in freshwater sediments contaminated by WWTPs.
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distribution and survival of faecal indicator bacteria in the sediments of the bay of vidy lake geneva switzerland
Ecological Indicators, 2009Co-Authors: Laurence Haller, John Pote, Jeanluc Loizeau, Walter WildiAbstract:Abstract The purpose of this study was to determine the concentrations and the horizontal distribution of faecal indicator bacteria (FIB) including Escherichia coli and Enterococcus sp. in the bottom sediments of the Bay of Vidy, City of Lausanne, Switzerland. A vertical distribution of FIB in sediments near the municipal wastewater treatment plant (WWTP) Outlet was evaluated and their persistence in those sediments was monitored for a period of 90 days. High FIB levels were measured in the sediments sampled near the WWTP Outlet Pipe and the mouth of the Chamberonne River, at concentrations ranging between 105 and 107 CFU 100 g−1. FIB levels at 10 cm depth in the sediments near the WWTP Outlet Pipe ranged between 104 and 105 CFU 100 g−1, and were still detected in the top 6 cm after 90 days. Results of this study indicate that freshwater sediments of the Bay of Vidy constitute a reservoir of faecal indicator bacteria, which can persist in certain areas of the bay. Possible resuspension of FIB and pathogens may affect water quality and may increase health risks to sensitive populations during recreational activities. FIB survival in sediments for long periods is of considerable significance for the understanding of microbial pollution in water and for the management of risk at specific recreational coastal sites.
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effects of a sewage treatment plant Outlet Pipe extension on the distribution of contaminants in the sediments of the bay of vidy lake geneva switzerland
Bioresource Technology, 2008Co-Authors: John Pote, Andrea G Bravo, Laurence Haller, Jeanluc Loizeau, Vincent Sastre, Walter WildiAbstract:In 2001, the municipality of Lausanne extended the Outlet Pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the Outlet Pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the Pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement.
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characterizing water circulation and contaminant transport in lake geneva using bacteriophage tracer experiments and limnological methods
Environmental Science & Technology, 2007Co-Authors: Nicola Goldscheider, John Pote, Laurence Haller, Walter Wildi, Jakob ZopfiAbstract:Multi-tracer tests with three types of marine bacteriophages (H4/4, H6/1, and H40/1), together with various limnological methods, including physicochemical depth profiling, surface drifters, deep current measurements, and fecal indicator bacteria analyses, have been applied to characterize water circulation and pathogen transport in the Bay of Vidy (Lake Geneva, Switzerland). The experimental program was carried out twice, first in November 2005, when the lake was stratified, and a second time during holomixis in February 2006. The bacteriophages were injected at three points at different depths, where contaminated waters enter the lake, including the Outlet Pipe of a wastewater treatment plant, a river, and a stormwater Outlet. Thereafter, water samples were collected in the lake at 2 m depth during a 48 h sampling campaign. The results demonstrate that (i) contaminated river water spreads rapidly in the bay; (ii) a well-developed thermocline is highly effective in preventing contamination from the depth...
Jeanluc Loizeau - One of the best experts on this subject based on the ideXlab platform.
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bacterial communities in trace metal contaminated lake sediments are dominated by endospore forming bacteria
Aquatic Sciences, 2014Co-Authors: Loic Sauvain, Jeanluc Loizeau, Matthieu Bueche, Thomas Junier, Matthieu Masson, Tina Wunderlin, Roxane Kohlermilleret, Elena Gascon Diez, Marylou Tercierwaeber, Pilar JunierAbstract:Lake sediments in areas close to the Outlet of wastewater treatment plants are sinks for pollutants. Bacterial communities in sediments are likely affected by the released effluents, but in turn they might modify the distribution and bioavailability of pollutants. On the shore of Lake Geneva, Switzerland, wastewater from the City of Lausanne is treated and discharged into the lake via an Outlet Pipe in the Vidy Bay. The objectives of this study were to assess (1) the impact of the treated wastewater release on the bacterial communities in the Vidy Bay sediments and (2) the potential link between bacterial communities and trace metal sediment content. Bacterial community composition and abundance were assessed in sediments collected in three areas with different levels of contamination. The main factors affecting bacterial communities were inferred by linking biological data with chemical analyses on these sediments. Near to the Outlet Pipe, large quantities of bacterial cells were detected in the three upper most cm (3.2 × 109 cells assessed by microscopy and 1.7 × 1010 copies of the 16S rRNA gene assessed by quantitative PCR, per gram of wet sediment), and the dominant bacterial groups were those typically found in activated sludge (e.g. Acidovorax defluivii and Hydrogenophaga caeni). Three samples in an area further away from the Outlet and one sample close to it were characterized by 50 % of endospore-forming Firmicutes (Clostridium spp.) and a clear enrichment in trace metal content. These results highlight the potential role of endospore-forming Firmicutes on transport and deposition of trace metals in sediments.
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distribution and survival of faecal indicator bacteria in the sediments of the bay of vidy lake geneva switzerland
Ecological Indicators, 2009Co-Authors: Laurence Haller, John Pote, Jeanluc Loizeau, Walter WildiAbstract:Abstract The purpose of this study was to determine the concentrations and the horizontal distribution of faecal indicator bacteria (FIB) including Escherichia coli and Enterococcus sp. in the bottom sediments of the Bay of Vidy, City of Lausanne, Switzerland. A vertical distribution of FIB in sediments near the municipal wastewater treatment plant (WWTP) Outlet was evaluated and their persistence in those sediments was monitored for a period of 90 days. High FIB levels were measured in the sediments sampled near the WWTP Outlet Pipe and the mouth of the Chamberonne River, at concentrations ranging between 105 and 107 CFU 100 g−1. FIB levels at 10 cm depth in the sediments near the WWTP Outlet Pipe ranged between 104 and 105 CFU 100 g−1, and were still detected in the top 6 cm after 90 days. Results of this study indicate that freshwater sediments of the Bay of Vidy constitute a reservoir of faecal indicator bacteria, which can persist in certain areas of the bay. Possible resuspension of FIB and pathogens may affect water quality and may increase health risks to sensitive populations during recreational activities. FIB survival in sediments for long periods is of considerable significance for the understanding of microbial pollution in water and for the management of risk at specific recreational coastal sites.
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effects of a sewage treatment plant Outlet Pipe extension on the distribution of contaminants in the sediments of the bay of vidy lake geneva switzerland
Bioresource Technology, 2008Co-Authors: John Pote, Andrea G Bravo, Laurence Haller, Jeanluc Loizeau, Vincent Sastre, Walter WildiAbstract:In 2001, the municipality of Lausanne extended the Outlet Pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the Outlet Pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the Pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement.
Laurence Haller - One of the best experts on this subject based on the ideXlab platform.
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distribution and survival of faecal indicator bacteria in the sediments of the bay of vidy lake geneva switzerland
Ecological Indicators, 2009Co-Authors: Laurence Haller, John Pote, Jeanluc Loizeau, Walter WildiAbstract:Abstract The purpose of this study was to determine the concentrations and the horizontal distribution of faecal indicator bacteria (FIB) including Escherichia coli and Enterococcus sp. in the bottom sediments of the Bay of Vidy, City of Lausanne, Switzerland. A vertical distribution of FIB in sediments near the municipal wastewater treatment plant (WWTP) Outlet was evaluated and their persistence in those sediments was monitored for a period of 90 days. High FIB levels were measured in the sediments sampled near the WWTP Outlet Pipe and the mouth of the Chamberonne River, at concentrations ranging between 105 and 107 CFU 100 g−1. FIB levels at 10 cm depth in the sediments near the WWTP Outlet Pipe ranged between 104 and 105 CFU 100 g−1, and were still detected in the top 6 cm after 90 days. Results of this study indicate that freshwater sediments of the Bay of Vidy constitute a reservoir of faecal indicator bacteria, which can persist in certain areas of the bay. Possible resuspension of FIB and pathogens may affect water quality and may increase health risks to sensitive populations during recreational activities. FIB survival in sediments for long periods is of considerable significance for the understanding of microbial pollution in water and for the management of risk at specific recreational coastal sites.
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effects of a sewage treatment plant Outlet Pipe extension on the distribution of contaminants in the sediments of the bay of vidy lake geneva switzerland
Bioresource Technology, 2008Co-Authors: John Pote, Andrea G Bravo, Laurence Haller, Jeanluc Loizeau, Vincent Sastre, Walter WildiAbstract:In 2001, the municipality of Lausanne extended the Outlet Pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the Outlet Pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the Pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement.
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characterizing water circulation and contaminant transport in lake geneva using bacteriophage tracer experiments and limnological methods
Environmental Science & Technology, 2007Co-Authors: Nicola Goldscheider, John Pote, Laurence Haller, Walter Wildi, Jakob ZopfiAbstract:Multi-tracer tests with three types of marine bacteriophages (H4/4, H6/1, and H40/1), together with various limnological methods, including physicochemical depth profiling, surface drifters, deep current measurements, and fecal indicator bacteria analyses, have been applied to characterize water circulation and pathogen transport in the Bay of Vidy (Lake Geneva, Switzerland). The experimental program was carried out twice, first in November 2005, when the lake was stratified, and a second time during holomixis in February 2006. The bacteriophages were injected at three points at different depths, where contaminated waters enter the lake, including the Outlet Pipe of a wastewater treatment plant, a river, and a stormwater Outlet. Thereafter, water samples were collected in the lake at 2 m depth during a 48 h sampling campaign. The results demonstrate that (i) contaminated river water spreads rapidly in the bay; (ii) a well-developed thermocline is highly effective in preventing contamination from the depth...
Andrea G Bravo - One of the best experts on this subject based on the ideXlab platform.
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distribution of mercury and organic matter in particle size classes in sediments contaminated by a waste water treatment plant vidy bay lake geneva switzerland
Journal of Environmental Monitoring, 2011Co-Authors: Andrea G Bravo, Sylvain Bouchet, David Amouroux, John Pote, Janusz DominikAbstract:In Lake Geneva, Switzerland, the most Hg-contaminated sediments have been found in the Vidy Bay where high Hg contents largely exceeds the background levels of Lake Geneva sediments. This contamination has been attributed to the discharge of a waste water treatment plant (WWTP). Total Hg (THg) and monomethylmercury (MMHg) were determined in bulk sediment and in three different grain size fractions (i: clay and silt, ii: fine-coarse sand, iii: and very coarse sand and gravel) collected close to the Outlet Pipe of a WWTP in order to verify whether the standardized procedures of sediment treatment is adequate for this setting and, by extension, for similar contaminated sites. THg was homogeneously distributed in the different grain size fractions and was correlated to organic matter content (R2 = 0.6). MMHg was homogeneously distributed in the two finer grain fractions (Φ < 0.063 mm; 0.063 mm < Φ <1 mm). The results of this study suggested that the analysis of the bulk sediment seems to be more appropriate for the assessment of the content and spatial distribution of Hg in freshwater sediments contaminated by WWTPs.
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effects of a sewage treatment plant Outlet Pipe extension on the distribution of contaminants in the sediments of the bay of vidy lake geneva switzerland
Bioresource Technology, 2008Co-Authors: John Pote, Andrea G Bravo, Laurence Haller, Jeanluc Loizeau, Vincent Sastre, Walter WildiAbstract:In 2001, the municipality of Lausanne extended the Outlet Pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the Outlet Pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the Pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement.
