Reports that water pollution in Galway can be blamed on sewage being pumped into Lough Corrib at Oughterard have been dismissed as simplistic by the Minister for Community, Rural and Gaeltacht Affairs Éamon Ó Cuív.
As people in Galway city and parts of the county faced into their third week of having to boil tap water, the number of people confirmed with the cryptosporidium parasite jumped to 155.
Health officials repeated their warning to 90,000 householders not to use tap water for teeth brushing or washing food, after at least one person contracted the bug from using contaminated water to brush their teeth and had to be admitted to hospital.
Mr Ó Cuív said it was clear that the sewage treatment works in Oughterard were "totally inadequate" to cope with the number of houses in the area, which is why the Connemara town had been approved for a new plant.
However, treatment plants were not the only possible source of pollution, as tests had shown that both human and animal waste had been identified in the water, he said.
"It's not that simple to say the pollution is coming from the Oughterard works. You have a sewage treatment plant in Tuam, which is nowhere near Lough Corrib, but it feeds into the Clare River. One theory is that the severe flooding before Christmas meant that farms and septic tanks got flooded," he said.
"Inadequate sewage treatment plants are not the only cause. We have to eliminate the possibility of pollution from agriculture and forestry.
"I heard that a calf can produce a billion spores of cryptosporidium. We are tackling the issue and the only way is to upgrade the sewage system one by one," said Mr Ó Cuív.
Ciarán Hayes, director of services for transportation and infrastructure in Galway City Council, said the council was continuing to conduct tests but had so far been unable to pinpoint any specific site or cause.
One official pointed out that any samples taken near a treatment plant would always show higher incidences of the bug.
Yesterday another Government minister weighed into the political row.
Minister of State for Justice, Equality and Law Reform Frank Fahey accused the city council of failing to submit plans to upgrade a water treatment plant.
He called on the Environmental Protection Agency (EPA) to investigate allegations of illegal dumping of dead animals in the Corrib catchment area.
Mr Fahey has also requested that the Minister for Agriculture Mary Coughlan provide him with statistics on the number of dead animals being legally removed from the Corrib catchment area in recent years, particularly in the areas of Headford, Annaghdown and Claregalway.
In his first statement on the crisis, Mr Fahey said €21.5 million had been allocated to Galway City Council by the Department of Environment, Heritage and Local Government in 2002 to upgrade the old water treatment plant at Terryland, which is at the centre of the cryptosporidium pollution scare.
"The department is still awaiting a preliminary proposal for the upgrading of this plant by Galway City Council.
"While I don't wish to apportion blame, I have been informed by department officials that they have received reports about this treatment plant over the last few years, but the council have not submitted any plans for the actual upgrading of the facility," he said.
On Friday, the Minister for the Environment, Dick Roche, had an emergency meeting with city, county and health officials and pledged to fast-track the €21 million treatment plant and provide a further €27 million for increased storage and water conservation measures in Tuam to help in the longer term.