Public warned of algal bloom presence at Loch Watten, Caithness

13th August 2019

The Highland Council is warning the public of the presence of an algal bloom at Loch Watten, Caithness, following an examination of sample water on Monday (12/08/19).

As a precautionary measure, environmental health have posted notices next to the water body, warning that contact with the algal scum or material should be avoided. Adjoining landowners and fishing interests have been advised of the situation as have NHS Highland and SEPA.

Guidelines for safe-practice in managing recreational waters published by the World Health Organisation indicate that during formation of cyanobacterial scum there may be potential for acute poisoning, long-term illness with some cyanobacterial species, and short-term adverse health outcomes, e.g. skin irritations, gastrointestinal illness.

Posters erected in the Loch Watten area warn the public that:

Swallowing the water or algal scum can cause stomach upsets or more serious health effects.

Contact with the water or algal scum can cause skin problems.

It is a sensible precaution for you, your children and your animals to avoid contact with the scum and water close to it.

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 irritations, vomiting and diarrhoea, fever and pains in muscles and joints. Toxic algae have caused deaths of livestock and dogs, waterbirds and fish. The treatment of water supplies removes blue-green algae and additional treatment may be applied to destroy or remove toxins should they arise. 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.