The public have been warned not to swim at Mullaghmore Beach today.
The temporary restrictions have been put in place by Sligo County Council and will remain in place until it is proven that there is no risk to bathers.
High levels of bacteria, which is typically excreted in the faeces of humans and other warm-blooded animals, was found in samples.
Following consultation the HSE and the Environmental Protection Agency and in accordance with national protocol the HSE recommended a prohibition on bathing as a precautionary measure.
