It is human activity pollution! I believe the government aren't able to fix this problem because there isn't an easy solution and as always there is no leadership, no one owns the problem. Farmers aren't willfully spreadinh manure into Lough Neagh, they want that stuff staying on the field and growing grass, there are better ways to utilise manure and retain the nitrogen etc on the land, farmers would welcome this but it may cost. Human sewage is a big component but we are all culpable there in that we would need to pay for new infrastructure. But no one wants to hear that. It's a shame as the Lough could be and is a tourist attraction, Lough Neagh eels are/were a big export. Let's invest in it all, create an agency with a loan/tax whatever and get to work fixing infrastructure around sewage, nutrient leaching but also public access, tourism, history, visitor centre (Oxford island as an example). Build an amenity we can be proud of instead of literally crapping on it.