An investigation is under way into oil pollution in a Norwich river, with dog owners warned not to let their pets go into the water.
Officers from the Environment Agency are trying to pinpoint the precise source of the pollution to the River Yare, close to the University of East Anglia at Colney.
They had initially attended before Christmas, carried out investigations and put in booms to control the issue.
They returned on December 30, putting in new booms to try to minimise the impact of the oil.
But, on Friday, January 1, they received a number of fresh calls from members of the public concerned that oil was polluting the river.
With the area popular among dog walkers, it has prompted the Environment Agency to issue a plea to owners to keep their pets away from the river.
Investigations are due to continue on Saturday, with officers from the agency once again attempting to establish the exact source of the pollution.
An Environment Agency spokesperson said: "Our officers are continuing to respond to an ongoing incident involving pollution in the River Yare at Colney in Norwich.
“Following initial reports of oil in the water on December 22, officers attended and traced the source to a surface water outfall pipe serving a research park and University of East Anglia buildings.
"Officers attended again the following day but were unable to trace the exact source of the pollution within the surface water system.
"A boom was put into the river to minimise the impact of the oil."
“There were no further reports of pollution until December 30, which prompted officers to install additional booms.
“On New Year's Day, several calls have been received from members of the public and officers have again been on site.
"A boom is in place to contain the pollutant and dog walkers are advised to avoid letting their pets enter the water.
"Officers are working with the university and will be back on site tomorrow for further investigations.”
The area around the UEA was hit by flooding over the Christmas period.
The River Yare burst its banks, which led to water flowing into the UEA Broad and the closure of popular walking routes.
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