A Co Derry water sports centre is to close permanently following the outbreak of toxic blue-green algae in the River Bann.
Ten members of staff at the Cranagh Activity Centre in Colerane have lost their jobs following the closure.
It comes after the centre was forced to shut for two weeks last month after the blue-green algae was detected at a number of sites across the north.
It can cause illness in humans and is particularly dangerous for pets.
Owner Rob Skelly told the BBC: "The algae seemed to clear and we managed to get open again, then last Sunday it appeared again overnight and the river was absolutely full of it.
"You couldn't put people into the water."
Mr Skelly added that the centre, which opened in 2015, had "been his life".
"My children grew up in the river and we've had over a quarter of a million customers over the years - it's just absolutely devastating," he said.
NI Water said there is a complex range of pressures across multiple sectors impacting on the water quality.
It said it does not pump raw sewage into Lough Neagh, but that during heavy rainfall "diluted waste water may be discharged" into the lough from a sewer overflow system.
In a statement, NI Water said that "in conjunction with Northern Ireland Environment Agency, have a prioritised approach to capital investment to ensure those assets causing the most impact to public health and/or the environment are upgraded first".
