People are being warned not to go into the water at St Andrews after mounds of debris were dumped at East Sands.
Astonished visitors described how dumper trucks deposited between 40-50 piles of rubbish-strewn silt on the sands over the weekend, leaving the water black.
Environmental officials launched an investigation after outraged residents raised complaints.
It is understood a contractor dredged the debris - which included draining pipes, an oil drum, bricks and litter - from Kinness Burn and St Andrews Harbour.
A local surfer (44) said: ““The water was so black, I could not see my feet in it.
“An electronic sign at East Sands said ‘pollution incident - you are advised not to bathe or paddle on the beach.
She added: “On Friday and Saturday they were driving the dumper trucks into the sea and dumping rubbish straight into the water. That rubbish will never be seen again.
“It’s incredible. It beggars belief. Common sense dictates that this rubbish does not belong there.”
SEPA - the Scottish Environmental Protection Agency - said it had recieved a number of complaints from residents.
“Given the location of the deposits, Marine Scotland is currently engaging with the Harbour Trust to arrange for the material to be removed and ensure that no further deposits are made on the beach,” a spokesman said.
“SEPA officers are currently undertaking an inspection of the beach as a designated EU bathing water and SEPA’s electronic sign at East Sands has been updated to advise against swimming or paddling in the water until all material has been safely removed. While monitoring is ongoing, SEPA has also been in discussion with Fife Coast and Countryside Trust and Marine Scotland to advise that all material is properly disposed of to a licenced facility able to accept the waste.”
According to witnesses, the beach has now been cleared and silt dredged up from the burn is now being deposited at the harbour mouth.