Ireland's Largest Lake is an Ecological Disaster

An apocalyptic amount of toxic blue-green algae is poisoning Lough Neagh, the largest freshwater lake in Ireland and the United Kingdom.

The lake that supplies 40% of Northern Ireland's drinking water has been overtaken by deadly bacteria brought on by sewage and agricultural runoff, forcing people and animals out of the water and beaches remaining closed to swimmers earlier in the year. In addition, it supports the biggest commercial wild eel fishery in Europe, is home to rare wildlife species, and also serves as an important centre for overwintering birds in the surroundings areas.

There are major health issues in addition to the fact that it is killing fish, birds, and dogs that enter the lake. Excess nutrients, such as nitrates and phosphates from sewage and farming discharge, are the primary cause of the dangerous cyanobacteria, and the stench is strong and sickening, which is becoming a serious concern for public health and safety.

The toxic green algae of Lough Neagh. Picture taken by Aodhan Roberts.

A recent study by researchers at Queen’s University Belfast (QUB) has confirmed that Lough Neagh as hypertrophic, the worst category of waterway nutrient pollution. This indicates that there have been "decades of agricultural, industrial, and domestic runoff."

The spread of the invasive zebra mussel species is also believed to have played a role in making the water more clearer, allowing more sunlight to penetrate, stimulating more algal photosynthesis. Freshwater, coastal, and marine waters are all home to green-blue algae by nature. It needs carbon dioxide, nutrients, and sunlight to grow and reproduce, just like plants do.

The study's main conclusion and suggestion is that everyone involved, including the government in Northern Ireland, should make lowering agricultural runoff and discharge from human wastewater treatment their top priority. The ecological effects and risks to the environment and public health posed by the blue-green algae in Lough Neagh were the main focus of the study and that immediate action should be taken to tackle the serious issues at Lough Neagh. A combination of pollution without penalty and political failure for decades are most certainly to blame for this ecological disaster. It will take many years for the lake to recover.

Lough Neagh has suffered from severe pollution over the years.