Algae Bloom Prompts Warning
The Environment Agency has issued an alert, warning the public to avoid swimming at the Ham and Kingston river bathing area on the Thames in west London. This is due to the discovery of blue-green algae, which can be toxic in high concentrations, posing a risk to humans, animals, and wildlife. The agency will collect water samples over the next day to assess the severity of the algal bloom, which flourishes in hot and dry weather conditions.[S1][S2]
Richmond Council has issued a warning to swimmers and visitors, urging them to stay out of the water in a newly designated bathing area along the Thames. This section, located between the Half Mile Tree and the YMCA Hawker Centre, was recently recognized as London's inaugural bathing water site in May. However, the water quality remains unclassified, with classification pending after the bathing season concludes on September 30th. In the meantime, the council advises against swimming and recommends keeping pets away from the water, as well as avoiding any visible algae along the riverbank.[S1][S4]
Campaigners and Swimmers React
Activists from SOLAR (Save Our Lands and River) have raised concerns about toxic algae growth, which thrives in warm weather and sewage-contaminated water. This is a serious issue in the area downstream from the Hogsmill, which recently failed an environmental audit. Marlene Lawrence, founder of Teddington Bluetits, a swimming group, reported a severe rash with itchy spots after swimming in the river, likely caused by the algae.[S1][S2][S5]
The recent toxic algae discovery in London's new bathing spot prompts concerns regarding Thames Water's proposal to introduce 75 million litres of treated sewage daily into the river. This plan, named the Teddington Direct River Abstraction, involves extracting water from the Thames during droughts and substituting it with treated wastewater from Mogden Sewage Treatment Works. Despite Thames Water's assurance that the project will maintain water quality and adhere to environmental regulations, the algae issue raises questions about potential risks to human health and the environment.[S1][S6]
Broader Water Quality Concerns
The Environment Agency (EA) has issued a warning to downstream abstractors and notified the UK Health Security Agency. They suspect that the toxic algae may have spread to the Thames stretch between Hampton and Kingston. This blue-green algae, or cyanobacteria, thrives in warm, dry weather with low rainfall and calm waters. It can generate toxins harmful to wildlife, livestock, and pets, and can cause skin irritations and health issues in humans if ingested.[S3][S4]
Amidst this incident, a recent evaluation highlights the poor ecological condition of England's water bodies. The Environment Agency's latest report, adhering to retained EU regulations, assessed 4,658 rivers, lakes, and coastal areas. Shockingly, only 14.3% met the criteria for good ecological status in 2025. Sewage spills, agricultural runoff, and urban pollution are the main culprits behind this concerning statistic.[S5]
