Authorities in Kerry are trying to identify the source of an oil leak which has entered the River Feale, the main source of water for the Listowel and surrounding North Kerry area, and an important salmon and sea trout river.
The Water Treatment Plant at Dromin was shut down overnight as the oil leak was believed to be close to the water intake point for the drinking water reservoir.
The pollution was spotted late yesterday and crews dispatched from Kerry County Council Water Services, Irish Water and Inland Fisheries.
At one stage it was feared the oil had emanated from upriver on the Feale near Abbeyfeale and Limerick County Council was involved.
However it's now believed the leak occurred within three miles of Listowel, between the Smearlagh Bridge and the main bridge at Listowel said local councillor, Jimmy Moloney, who has been monitoring the situation.
Crews had also looked into whether it might emanate from the Smearlagh River, a tributary of the Feale, the Fianna Fáil councillor said.
The River Feale, which rises in the Mullaghareirk Mountains and flows through Abbeyfeale and Listowel before entering the sea at Cashen near Ballybunion, is one of the most important salmon and sea trout rivers in the country. It is also famous for brown trout.
Meanwhile, an apparatus is being installed to filter out any oil pollution that might enter the drinking water reservoir or damage the pumping equipment.
Irish Water said low water pressure and some outages were to be expected. They have appealed to customers to conserve water wherever possible. A helpline has been established at 1850 278 278.