Seine's Water Quality Sparks Concerns Ahead of Paris Olympics

The River Seine's water quality has raised alarms just as the Paris Olympics begin. Despite heavy rains affecting cleanliness, Mayor Anne Hidalgo has made public efforts to allay worries. Investments since 2015 aimed at cleaning the river continue, but fluctuating test results question its safety for swimming events.

Water quality tests have revealed that the River Seine currently does not meet the standards required for authorized swimming, just as the Paris Olympics are set to kick off. Concerns have been revived by heavy rain during the opening ceremony, questioning whether the long-polluted waterway will be clean enough for swimming competitions.

Paris Mayor Anne Hidalgo recently took a highly publicized swim to mitigate these fears. The Seine is slated for marathon swimming and triathlon events. Daily tests, which measure E. coli levels, showed that the water quality at Bras Marie exceeded the safe limit of 900 colony-forming units per 100 milliliters, reaching 985 on June 17 when Hidalgo swam.

Further tests from two other downstream sites showed results within the acceptable range. Nevertheless, water quality fluctuates due to irregular rainfall, often doubling the Seine's usual summer flow. Investments totaling $1.5 billion since 2015 aimed at cleaning the river for the Olympics include constructing a massive underground water storage basin, renovating sewer systems, and upgrading wastewater treatment plants, although safety remains uncertain.