Green-Blue algae, what is it and why is it keeping people out of sea at Castlerock and Portstewart

The National Trust said in a social media that a potentially toxic blue-green algae had been found at the north coast beaches.

Castlerock and Portstewart beaches have been red-flagged by the RNLI as unsafe for bathing. The National Trust said a potentially toxic blue-green algae had been found at the north coast beaches.

It can cause illness in humans and animals and there has been a number of dog deaths due to the Algae

Emma Cunningham, North Coast General Manager at The National Trust said: “We’re really disappointed that people can’t use these beaches and unfortunately the presence of these algal blooms at beaches is a symptom of a wider problem of poor water quality.

"The most recent government report on water quality in Northern Ireland found that that no rivers or lakes are in good condition, meaning that we are failing to keep our rivers and lakes clean and healthy.

"The Neagh Bann catchment is a vital ecosystem and this presence of algae is a sign that we need to better look after our inland and coastal waters.

“The Department for Infrastructure is consulting on a budget that proposes not to treat wastewater, which would potentially see an increase in sewage getting into the water systems.

"We’re working with partners across the environment sector to oppose any measures that would see any more backward steps in water quality."

What has been found on the beaches?

Blue-green algae. It can cause illness in humans and animals have been found across Northern Ireland during the warm weather we have had.

Why has this algae appeared?

The National Trust says the issue a symptom of a wider problem of poor water quality and its appearance a sign of how there is a need to look after waterways better.

The potentially blooms often increase in the summer months, due to warm waters which allow the bacteria to multiple.

Normally the blooms are in freshwater lakers, rivers and streams.

The algae can be influenced by increased nutrients in the water which often comes from agricultural or sewage run off into the river.

Despite its usual occurrence in freshwater, the bacteria has started to crop up in coastal and off-shore areas around the UK and Ireland.

Where has the algae been found and where had it come from?

The blue-green algae found in the water in Castlerock and Portstewart is a freshwater species and is likely to have come from the River Bann.

What to do if you have come into contact with the algae.

The Public Health Agency advises anyone who has come into contact with wate to shower with fresh water immediately.

The PHA says if you have come into contact or drunk affected water and feel unwell you should obtain medical attention.

Symptoms generally begin within hours after exposure.

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