Toxic Algae Prompts Thames Swim Ban at Ham and Kingston
Environment Agency extends warning as blue-green algae discovered near Thames Water's Hogsmill plant, raising infrastructure concerns.
Sarah Connor
A do not swim warning has been issued at London's only Thames bathing spot in Ham and Kingston.
Bathing is not advised, due to pollution from harmful algae; an Environment Agency spokesperson identified blue-green algae on the lower River Thames, including the Ham and Kingston designated bathing water.
Environment Agency officers actively sample water along the river, extending the warning to a broader stretch of the Thames between Hampton and Kingston.
Local abstractors downstream and the UK Health Security Agency have received notification.
The algae reportedly thrives in warm, calm, and dry weather conditions; warming river temperatures make the Thames increasingly vulnerable to these blooms.
Flow levels at Kingston currently classify as 'exceptionally low' due to minimal rainfall.
Cyanobacteria, or 'blue-green algae', can produce toxins that reportedly cause skin rashes and illness in humans, and are potentially fatal to pets and wildlife.
Marlene Lawrence, a swimmer, quickly suffered a reaction, developing a rash and itchy spots, which she attributes to the algae in the river.
Instantly on Sunday night I came out in a really bad rash, itchy spots, and that's not like me. I can only attribute it to the algae in the river.
Neither she nor her fellow swimmers have ever encountered a blue-green algae bloom at this particular stretch of the Thames, Lawrence claims.
Thames Water’s Hogsmill sewage treatment plant sits just three miles upstream of the Ham bathing site.
Thames Water has postponed over 100 projects, including an upgrade to the Hogsmill works, now unlikely until 2028.
The regulator, Ofwat, investigates the failure to upgrade the Hogsmill infrastructure.
An Environment Agency spokesperson emphasised the danger: "It is important that members of public do not enter the Thames along this stretch. It is also vitally important to keep dogs out of the water."
The agency works with the Royal Borough of Kingston upon Thames, who have put signage in this location to warn people that it is not safe to swim, and an advice against bathing notice has been activated on the Swiminfo website.
A recent assessment, conducted under retained EU legislation, revealed only 14% of England's rivers, lakes, and coastal waters are in good ecological health, evaluating 4,658 surface water bodies.
The report attributes these widespread issues to sewage spills, agricultural nutrient runoff, and pollutants from urban areas and roads.