WATER users are warned they could suffer from vomiting and diarrhoea if they come into contact with potentially hazardous blue-green algae.

East Lothian Council issued a reminder as the algae, which are tiny organisms which develop naturally in lochs, ponds, reservoirs, rivers and the sea, can multiply during the summer.

They can discolour the water, which appears green, blue-green or greenish brown.

People and animals can be affected as a result of direct contact with water affected by blue-green algae.

Councillor Norman Hampshire, cabinet spokesman for the environment, said: “Our Environmental Health team routinely monitors levels of blue-green algae over the warmer months because of the potential health risk to people and to animals.

“Canoeists, wind surfers and swimmers who come into contact with the algal scum or who accidentally swallow affected water can suffer from complaints such as skin rashes, eye irritation, vomiting, diarrhoea, or pains in muscles and joints.

“These symptoms are usually mild, but in some cases, can be severe.

“The risk to small animals like dogs is significant over the summer months as they tend to drink more water in the heat and may eat shoreline algal crusts.

“Dog owners should keep an eye on their pets, especially if they come into contact with water which could be affected.

“The public should be reassured that public water supplies are always treated to prevent any harmful effects to health due to blue-green algae.”

Anyone who finds a loch, pond or river which they suspect is affected by blue-green algae and which is not displaying a warning sign, should contact Environmental Health or Sport, Countryside and Leisure on 01620 827365.