Swimming in the Seine River during the 2024 Olympic Games: What are the risks for athletes? An assessment of the microbiological and chemical risks

Abstract

Introduction: Several events at the 2024 Olympic and Paralympic Games in Paris are scheduled to take place in the Seine River, a body of water previously considered unbathable according to current European and national regulations. The aim of this study is to assess the microbiological and chemical risks incurred to athletes during these events. Method: Using data from the literature, pathogens and hazardous substances potentially present in the Seine were identified and different exposure scenarios for athletes were determined. Where recent data on measurements in the Seine River were available, a risk assessment was proposed. Results: In terms of microbiological risk, the fecal indicators recommended for recreational waters do not comply with the sufficient quality thresholds. Among the other pathogens identified, the latest leptospirosis assay data for 2018 did not reveal any pathogenic form, even though the disease is circulating in the Paris region. In terms of chemical risk, the available measurements in the Seine systematically show concentrations well below the risk thresholds identified in the literature. However, some substances identified as dangerous have not yet been measured in the Seine and their risk cannot be assessed. Conclusion: Many of the hazards identified are not currently covered by current regulations and are therefore not adequately monitored to enable preventive measures to be taken to reduce the health impact of this event. While the data on chemical risks are reassuring, the data on microbiological risks suggest a high level of contamination and the possible presence of other agents that need to be addressed.