A stretch of the River Axe at Mosterton, Dorset is being polluted by an oil leak.
Officers at the Environment Agency today said the leak is “small and hard to find” and are appealing for any information regarding the source of pollution.
They tried to find the “mysterious” leak on several occasions last year but failed to spot it.
Last month, the oil leak returned and the Agency believes it has a constant drip, which makes its way into the surface water drainage system from Bowes Lane.
The Environment Agency is urging people to come forward with any details.
Doug Parker for the Agency said: “[Due to] the nature of the oil it is causing an odour nuisance down the length of the High Street as well as polluting the Axe. It is possible this problem has returned because a heating oil tank has been recently refilled.
“We would ask that any residents on a heating oil system to closely monitor their usage and oil level over these warmer months for any unusual losses.
“We urgently need to trace the source of the pollution as soon as possible to prevent any further risk to the environment.”
Members of the public can call the Environment Agency’s 24-hour hotline on 0800 807060 or the Devon Enquiries Team on 01392 352400.