18 of 2023 - Blue Green Algae

watch_later 06/09/23

Blue-Green Algae has been identified at Eldridges Lock, near Tonbridge on the River Medway Navigation. We expect positive samples to be found on elsewhere on the navigation and therefore this advice applies to the entire Medway Navigation.

What are Blue-Green Algae?

Blue-green algae are natural inhabitants of inland waters, during calm weather they rise to the surface to form a scum. This may look like paint, or jelly and may form flocs. Scums may be blue-green, grey-green, greenish-brown or occasionally reddish-brown in appearance. They may disappear and reappear on subsequent days and, as a result of wind action, may accumulate on the shoreline. Sometimes these algae may release toxins into the water.

Illnesses including skin rashes, eye irritation, vomiting, diarrhoea, fever, pains in muscles and joints have occurred in some recreational users of water who swallowed or swam through algal scum. There have been no reports of long-term effects or death in humans, but in some cases the illnesses were severe.

Blue-green algae can be toxic to dogs. Call your vet immediately if you suspect poisoning

Although algal scum is not always harmful, it is a sensible precaution to avoid contact with the scum and the water close to it.

Click HERE to learn more about Blue-Green Algae



River Status


All vessels using these waterways must be registered with the Environment Agency.

For further information call: 03708 506 506

Last updated: 19 May, 09:25 AM