Speaking to Lusa, the commander of Porto de Sines, Rui Filipe, said that the "red flag was raised", this morning, by lifeguards, to prevent bathing on the beach.
"As a result of the collected samples, which are regularly made by the Portuguese Environment Agency (APA) in bathing waters, the presence of E.coli [bacteria] was detected in the water, at levels above those appropriate for bathing," he said.
According to Rui Filipe, the results of the samples were sent to the maritime authority on Thursday night, by the APA, which "issued a warning against bathing on that beach".
"This morning, before 08:00, signs were placed warning of the situation at the entrance to the beach, and instructions were given for the red flag to be raised," he said.
According to Rui Filipe, a "second collection" of water samples from the bathing area has already been carried out, the results of which "will only be available" on Saturday.
"According to the results of the analyses, we will make an evaluation and take the decision to lift or maintain" the ban on bathing, he added.
Until the restrictions are lifted, bathers "can remain on the beach, but bathing" is not advised.
"There was no need to remove bathers from the water because the information was already available before the beach opened and the instruction was given to lifeguards to advise against bathing," he explained.
The commander of Porto de Sines indicated that the origin of contamination by concentration of faecal coliforms "is unknown" and that it was necessary to "raise the red flag" until the situation is back to normal.