Swimmers advised to avoid sea at beaches across Fylde coast following pollution risk warning
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The Environment Agency (EA), which assesses the quality of the water at bathing sites, said the increased risk of pollution was due to weather and “other predictable factors”.
They added the warnings were not due to sewage.
A spokeswoman for the EA said: “To help bathers understand what water quality is likely to be on a given day, we carry out daily pollution risk forecasts throughout the summer.
“We issue a warning and advice against bathing if we become aware of a pollution incident or if we forecast that quality is likely to be reduced because of predictable factors like rain, wind or tides.
“Warnings are posted on Swimfo and displayed on signs at the beach so bathers can make informed decisions before deciding whether to enter the water.”
St Annes North and St Annes were not affected.
Pictures taken at the beach in Cleveleys on Thursday showed contractors taking a water sample for testing.
The beaches remained open but the public were advised not to swim in the sea.
Earlier this year, raw sewage mixed with rainwater was released into the sea near Blackpool.
This was caused by a burst pipe which became overwhelmed as 1.7 inches (44mm) of rain fell in two hours during a severe thunderstorm.