Plans for a waterside park along the River Liffey in Dublin could be scrapped.
Tests carried out by South Dublin County Council have showed high pollution levels in the water between Leixlip and the Lucan Bridge.
The council took the samples ahead of proposals to develop a 'blueway' trail along the River Liffey.
But local Fine Gael Councillor William Lavelle says those plans are now in jeopardy.
"It's a river that runs right through the heart of our community, so having the water quality so poor is not something we should be proud of," he said.
"I'm more concerned that there doesn't seem to be an urgent enough response to deal with the problem."