Paul Daly (Fianna Fail) | Oireachtas source

Is there scientific proof? Is it a correlation because people know it happened? If something happens that people know happened and then something else happens somewhere else, it is very easy to blame one on the other. I am not saying there is not a correlation but is there scientific proof it was the cause? Many other things changed as well in the dry period. The levels of water dropped, there was the grime on the roads and concrete yards all over the country, and there was how sewage treatment plants performed. You name it, a lot of things changed. Is there scientific proof as to what caused the rise in the nitrogen level in the water? Is it just hearsay correlation because we know farmers were advised to put out more chemical nitrogen?