The test run for Olympic marathon swimming in the Seine River was canceled due to water quality concerns, as confirmed by World Aquatics and Paris 2024 spokesperson Anne Descamps. This cancellation follows a triathlon mixed relay event held the previous day, where bacteria levels were deemed acceptable for the shorter course swum by triathletes. However, the marathon swim course is significantly longer, raising concerns about fluctuating bacteria levels, particularly Enterococci, which exceeded acceptable thresholds during assessments. Another familiarization session is scheduled for Wednesday, with organizers hopeful that the marathon swimming events on August 8 and 9 will proceed as planned. The situation exemplifies ongoing water quality issues impacting the Paris 2024 Games, highlighting the need for continued monitoring.