Blue-green algae has been confirmed in more parts of Northern Ireland.
Lisburn and Castlereagh City Council said that the lake at Hillsborough Forest Park is currently contaminated with the algae.
It warned the material "may produce toxins that are a serious health risk to humans and pets if in contain with or ingested".
It comes as Fermanagh and Omagh District Council confirmed that blue-green Algae had also been found in Lower Lough Erne in the vicinity of Castle Archdale.
And Armagh, Banbridge and Craigavon Council has confirmed it has been found in parts of Lough Neagh.
Lisburn council has warned people not to catch or consume fish as the toxins can accumulate in them.
While Fermanagh and Omagh District Council Council says signage is in place to warn visitors.
It asks anyone who suspects the presence of the organism to report it to the Environmental Health Service.
Blue green algae is a naturally occurring organism which can be found in loughs, rivers and ponds and is most prevalent between May to September due to increased temperatures and sunlight.
It can bloom very quickly, therefore, residents and visitors are advised to exercise caution around waterways during periods of warm weather and bright sunlight.
Last month beaches on the north coast were red-flagged due to the presence of Blue-green algae.
In a statement, the Northern Ireland Environment Agency (NIEA) said it received reports of an algal bloom at Lower Lough Erne in the vicinity of Castle Archdale, Co. Fermanagh on Thursday, August 3 and has confirmed the presence of blue-green algae.
“NIEA has informed Fermanagh and Omagh District Council which has posted advisory messages on social media and erected signage warning the public of its presence.
“NIEA is encouraging everyone to get involved in citizen science and help monitor blooms of blue-green algae to help protect from public health risks and continue to enjoy our local water environment.
“The Bloomin’ Algae App enables members of the public to submit a photo of the bloom taken on their phone and state what activity takes place at the location, so that the potential risks to people and animals can be gauged.
“The submitted records are verified by trained environmental experts, enabling rapid feedback to the app user to verify if it may be blue-green algae, or something less harmful, and appropriate next steps they should take. Records will be used to alert authorities to provide early warnings of risks to other water users. The App is free to download directly from Google Play or App Store.
“Members of the public can report a suspected bloom through our incident hotline on 0800 80 70 60 or e-mail emergency-pollution@daera-ni. gov.uk with a photo, if possible, and details on the location of the potential bloom.”
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