Blue-green algae warning for tourists at Llyn Tegid in Bala

The blue-green algae could cause people to become unwell

Tourists have been warned to avoid a busy north Wales lake after a toxic algae was found in the water.

Snowdonia National Park Authority said to avoid the water at Llyn Tegid in Gwynedd if there is scum on it or if the water is not crystal clear.

Blue-green algae has also been spotted at two other Welsh lakes since May and can be brought on by warm weather.

It carries a high risk of skin rashes, eye irritation, vomiting, diarrhoea, fever and muscular or joint pain.

The authority added that it can be extremely harmful to animals who drink from the lake.

Llyn Tegid in Bala is a large freshwater glacial lake in Gwynedd, Wales

The blue-green algae, called cyanobacteria, occur naturally in inland waters, estuaries and seas, and cannot be removed or treated.

They thrive in warm conditions and are likely to come and go throughout the summer season.

It cause problems if swallowed, and occasionally cause more serious illness such as adverse effects on the liver and nervous system.

The authority has asked no one touch the algae and contact them if they see any.

The algae was found at Llangors Lake in May and at Llandrindod lake earlier in August, both in Powys.