Blue-green algae identified at Llangors Lake

Following information received from Public Health Wales and the Environment Agency Wales, the council’s Environmental Health Service are now advising against the use of the lake for any water based activities and owners of pets and livestock to avoid animals coming into contact with the body of water.


The location of the algae depends on environmental conditions such as wind direction and rainfall.  It also expands and contracts depending on the amount of sunlight and temperature.


The council will continue to work with the Environment Agency Wales, who will continue to test for algae in the lake and will only consider it to be free of blue-green algae when two clear samples are taken at least a week apart.  In the meantime, members of the public are being informed:


• not to enter the water 

• not to participate in water sports or recreational activities in or on the lake i.e., swimming, sailing, canoeing, fishing, water skiing etc 

• not to swallow the lake water 

• to avoid contact with the algae 

• not to eat fish caught in the lake 

• not to allow pets or livestock to come into contact with the lake water as it has the potential to be fatal to animals 

• observe and abide by notices positioned along the lake.


The algae produce toxins which can cause skin rashes, nausea, vomiting, stomach pains, fever and headache if swallowed.  Children are at greater risk than adults of developing problems because of their comparative lower body weight.


Steve Clinton, the council’s Public Protection Manager, said: “Blue-green algae has the potential to cause illness if swallowed or even by just coming into contact with it.  Blue-green algae occurs naturally in inland waters, estuaries and seas and cannot be removed or treated.”


Paul Sinnadurai, Conservation Manager for Bannau Brycheiniog National Park Authority explained that the situation must be taken seriously.  He said:  “Llangors Lake is a popular destination for locals and visitors and is an important site for water recreation, walking and bird watching.  We have taken immediate steps to advise residents, visitors and users of the lake to be sensible and to follow the advice from Powys County Council. It’s really important that people pay attention to these warning notices and make sure their children and their pets avoid contact with affected water.” 


A spokesperson for the Llangors Lake Management said:  “An algal bloom, which we reported to Environment Agency Wales two days ago has been detected on the Llangasty shoreline which is commonly used for quiet enjoyment and bird watching.


“Further inspections will be carried out by Environment Agency Wales to establish whether the main body of the lake is affected.  Although we have taken the decision to temporarily suspend the use of the lake we hope that people will soon be back to enjoy the activities that this beautiful lake provides.”


Tim England from Environment Agency Wales said: “We are continuing to monitor the lake, and will be taking regular samples to keep all interested parties aware of the current situation.  We are working closely with all the relevant authorities to advise them on how to minimise the risk to both the environment and local people.”


For further advice please contact:  Environmental Health Department, Powys County Council, Neuadd Brycheiniog, Cambrian Way, Brecon, Powys, LD3 7HR.  Tel no. 0845 6027037 and 01597 827467 or alternatively email: