Blue-green Algae Warning At Loch Watten, Caithness

29th July 2024

The Highland Council's Environmental Health team is advising caution as blue-green algae has been found in Loch Watten, Caithness.

During periods of prolonged warm weather, the chance of Blue Green algae (cyanobacteria) affecting water courses, particularly ponds, lochs and canals (as well as rivers), increases significantly.
Sometimes the blue green algae can form blooms, which can release toxins into the water.

Samples taken at Loch Watten have indicated the presence of blue-green algae.

Contact with blue-green algae can have health effects for humans and animals; the situation is being investigated by Highland Council Environmental Health Department in partnership with NHS Highland Public Health Department and wider colleagues. As a precautionary measure contact with the algal scum should be avoided by people and pets. Notices will be posted next to the loch warning that contact with the algal scum should be avoided.

Notes
Blue-green algae exist in fresh waters in Great Britain and throughout the world; they are noticed when their concentrations increase to form "blooms" and when they form scums - looking like blue-green paint – or when they collect on the shore line.
Some blue-green algae may give rise to adverse medical effects – but not always. Effects on people coming into contact with toxic scums include skin rashes, eye irritation, vomiting and diarrhoea, fever and pains in muscles and joints. Toxic algae have caused deaths of livestock and dogs, waterbirds and fish. The actions currently taken are precautionary.

The behaviour of algae is erratic.

The level of its toxicity can fluctuate; it can appear one day, be dispersed by the wind and mixing and re-accumulate at any time.