2024 Olympics - Seine Water Quality

 

 

To clarify: Fluidion is an entirely independent organization, with no affiliations with the City of Paris or the 2024 Olympics committee. We stand by our Open Data Initiative, rigorous scientific practices, and ethical standards. The data we provide are our property, shared transparently as part of our Open Data Initiative. These data are protected by copyright and require proper attribution as specified below.

 

The water quality data presented on this page are collected and reported by Fluidion as a best-efforts attempt to offer accurate, timely, and accessible information about the Seine River quality leading up to and during the Olympic events. The data come from samples collected by Fluidion personnel and trained citizen scientists under Fluidion’s supervision. Samples are taken from the Seine at the Alexandre III bridge in Paris, the site of the 2024 Olympic events.

 

These data are quality-controlled by Fluidion scientists, which may result in delays in data availability. Any errors found in the data are unintentional, and corrections are made immediately upon detection. The information and data provided are intended solely for scientific purposes. Fluidion assumes no responsibility for specific uses of these data, which are at the sole risk of the end-user.

 

All data presented on this page belong to Fluidion and are protected by copyright. Any use of the data must provide a clear reference to this website and include the following text: "Data provided courtesy of the Fluidion Open Data Initiative".

 

 

 

The dashboard below displays the latest three measurement results, illustrating both the values obtained using standard laboratory techniques and those provided by Fluidion® ALERT rapid microbiology instrumentation.

 

Standard culture-based laboratory methods for measuring E. coli, such as the most probable number method and membrane filtration and plating, cannot differentiate between individual bacteria and those clumped together in aggregates. In contrast, ALERT technology can accurately quantify both planktonic (free-floating) bacteria and those within aggregates. This capability provides a vital additional dimension of information for risk assessment, as fecal particles or aggregates loaded with pathogens and indicator bacteria can represent a substantially higher health risk. Thus, ALERT measurements report both planktonic and comprehensive E. coli counts.

 

Following the dashboard presenting the latest results, we provide graphs that plot the data across the entire intensive sampling period for 2024, beginning April 8, in both linear and logarithmic scales. Additionally, 95% confidence intervals are included to convey the uncertainty associated with the data. Relevant environmental factors, such as rainfall and river discharge, are also provided to aid in data interpretation.

 

Further details on how these data were collected can be found in the Methodology section below.

 

The data presented here undergo quality control by Fluidion scientists, which may lead to occasional delays in data availability. Any errors detected in the data are unintentional and corrected immediately.

 

 

All data available here belong to Fluidion and are protected by copyright. Any use of the data must provide a clear reference to this website and include the following text: "Data provided courtesy of the Fluidion Open Data Initiative". The data presented on this page are available for download in various plain text and open source formats, shown below. Fluidion assumes no responsibility for any specific usage or any decisions made that are based on these data. Any use of the data is under the sole responsibility of the end-user.

 

Data formats:

- Plain text PDF

- Comma-separated values (CSV)

- Tab-separated values (TSV)

 

 

The following figures provide the time-series data since early April, when our high-frequency monitoring efforts started. E. coli concentrations obtained from ALERT instrumentation (comprehensive - red triangles; planktonic - green inverted triangles) are juxtaposed with the MPN laboratory E. coli concentration (gold circle).  Local environmental factors are shown as well: daily precipitation (light blue line) and mean river discharge (dashed blue line). Standard deviation and 95% CI are shown as colored bands.

 

Figures are plotted using both linear and logarithmic scales for the bacterial concentration axis. The linear scale provides better visibility of the water quality exceedances., while the logarithmic scale is typical for analyzing bacterial concentration data, which is best modeled by a log-normal distribution.

 

The juxtaposition of environmental factors allows observing their effect on water quality. This is particularly true of rainfall, which can generate river pollution by combined sewer overflows.

 

Thresholds

The horizontal solid red line represents 1000 E.coli/100mL, while the dashed line represents 500 E.coli/100mL. These correspond to the guidelines for good and, respectively, very good inland water quality for swimming, published by the World Triathlon.

 

 

The latest three weeks of data are highlighted in the following graphs, allowing a focus on the most recent trends that were observed. The data update automatically. Figures are plotted using both linear and logarithmic scales for the bacterial concentration axis.

 

The E. coli concentrations obtained from ALERT instrumentation (comprehensive - red triangles - and planktonic - green inverted triangles) are juxtaposed with the MPN laboratory E. coli concentration (gold circle). The error bars represent the 95% confidence interval for each measurement. The different data series were slightly offset for improved graph legibility.

 

Thresholds

The horizontal solid red line represents 1000 E.coli/100mL, while the dashed line representes 500 E.coli/100mL. These correspond to the guidelines for good inland water quality published by the World Triathlon.

 

 

Samples were collected near the Alexandre III bridge (GPS coordinates: 48.863248, 2.314508) using standard grab sampling techniques, and then either processed onsite or transported to the laboratory in a cooler with ice. In the laboratory, samples were processed immediately.

 

Rapid microbiology ALERT data were obtained using Fluidion® ALERT LAB portable E. coli analyzers. Samples were analyzed as-received (to measure the comprehensive E.coli concentration) but also after 5µm filtration (to measure the planktonic E.coli concentration). 95% confidence intervals (CI) were obtained from peer-reviewed published scientific literature.

 

Laboratory most probable number (MPN) measurements were performed using the EPA-approved IDEXX Colilert-18 Quantitray-2000, following standardized protocols. Samples were measured as-received and also with a dilution of 1:100, to extend the measurement range of the MPN method. Dilutions were performed using sterilized glassware and autoclave-sterilized de-ionized water. The MPN laboratory measurement values and 95% CI were obtained from the IDEXX Quanti-Tray®/2000 MPN Table (per 100 mL) with 95% Confidence Limits.

 

Historical rainfall data in Paris (measured at the Montsouris station) were obtained from: https://prevision-meteo.ch/climat/mensuel/paris-montsouris. Historical Seine River discharge data (measured at the Austerlitz bridge in Paris) were obtained from: https://www.hydro.eaufrance.fr/stationhydro/F700000103/fiche