 The water in the river from the mine workings has a metal concentration |
Calls have been made for a river running through a play area on Anglesey to be fenced off over pollution fears. Tests have been carried out on acid levels in the river, Afon Goch, or "red river".
Amlwch town councillor Robin James said there were worries about a risk to children's health.
The Environment Agency agreed the pollution level was not satisfactory and work could involve an application for European money.
The agency has already pumped away millions of gallons of acidic water from old copper mine workings on Parys Mountain.
The river was already polluted before the removal of an old crumbling dam, but is now more acidic and the agency has been working towards getting the discharges treated.
But work could depend on an application for money under the European Objective 1 programme.
Mr James said: "We've received a letter which says the river is polluted, that it contains poison.
"Yet children are in the play area and the river flows through the middle of it."
Councillors have joined calls for the river to be fenced off, although the Environment Agency said this was a matter for the landowner.