A spokesperson from the Scottish Environment Protection Agency (SEPA) said:
The water quality at North Berwick (West) has a good classification, however a sample taken at the bathing water on 1 August 2016 showed that pollution was present at an elevated level.
“Extensive investigations and additional sampling have taken place since however we have been unable to conclusively determine the source of this result. We took investigatory samples from the bathing water on 5 August and 8 August which showed a return to more typical water quality and our compliance sample on 10 August again reflected this, leading us to conclude that that the cause of the pollution had ceased.
“However, early indications from a sample taken yesterday (15 August) show pollution to be present again. As such we would advise beach visitors to avoid swimming and paddling at this site. Our investigations will continue and we will work with our partners to resolve this issue and return the bathing water to its normal good condition. Our sample results show that this incident is very localised, and the bathing water at North Berwick (Milsey Bay) is unaffected.”