The River Thames has seen a significant spike in E. coli levels, with some areas measuring over 60 times the safe threshold for swimming.
Fulham Reach Boat Club recorded 58,000 colony-forming units (cfu) in 100ml of water, which is believed to have been caused by a spill at Fulham Reach.
Levels are graded as 'poor' once inland water reaches above 900 cfu per 100ml.
Thames Water confirmed that an isolated spill occurred at Fulham Reach during planned maintenance works for the Tideway Tunnel testing and commissioning programme.
This is despite the fact the £4.6 billion Tideway Tunnel was built in part to cut sewage pollution.
Campaign group River Action pointed out that the spills happened during dry weather on Thursday, which was the hottest June day on record with temperatures reaching highs of 36C.
This breached the rule of companies only being allowed to release sewage during heavy rainfall.
Although the stretch of the Thames at Fulham Reach is not designated for bathers, rowers and kayakers are often seen in the water.
Thames Water stated that the maintenance was scheduled during a period of dry weather to minimise operational risk, but an exceptional and highly localised storm occurred unexpectedly during this time, resulting in the spill.
The company is undertaking a detailed review of the circumstances, and any lessons learned will be applied to strengthen future maintenance planning and operational resilience, supporting the continued protection of the River Thames.
E. coli is a type of bacteria that can cause severe diarrhoea, stomach cramps, and fever, and can be transmitted through contaminated food, close contact with an infected person, or direct contact with an infected animal or its environment.
The most common symptoms of E. coli infections include diarrhoea, stomach cramps, nausea and vomiting, and a fever.
