River Enler 'turned chocolate brown by excavation works'
The Department of the Environment (DoE) is investigating reports of pollution in the River Enler in Co Down.
Calls to the Water Pollution Hotline claimed the water had been turned brown by excavation work on a bank between Dundonald and Comber.
One angler said the river was "chocolate brown", leaving it impossible to fish.
He saw the problem on Monday, but it had gone by the time inspectors came out, only to return once more yesterday.
The angler captured footage of the pollution before reporting it to the DoE. "It's the whole way from where there (are works) down the river and out to the estuary," he said. "They have left it unfishable.
"None of us have noticed any fatalities. But the fish have to be able to see to eat."
The Enler Angling Club said it was made aware of the pollution on Monday after members saw works being carried out in a field off the Ballyrainey Road, Comber.
"A JCB was being used to dig trenches for what looked like drainage pipes," a spokesman added.
"These works have badly affected the water quality. The relevant authorities were notified. We wait for their investigations."
The DoE said the Northern Ireland Environment Agency (NIEA) received a report of possible pollution on Monday.
"An NIEA Inspector is currently investigating the matter," a spokesman added.
"As the matter is under investigation, we cannot comment on any potential sources at this stage.
"The public may report any signs of water pollution on the Water Pollution Hotline on 0800 80 70 60."