Water event
Lough Neagh cyanobacterial blooms
Extensive blue-green algal blooms across the largest lake in the British Isles, which supplies around 40% of Northern Ireland’s drinking water.
Key facts
- Event type
- Algal bloom
- Started
- 2023-05-01
Cause
Long-term nutrient enrichment from agricultural runoff and wastewater, combined with warmer water and the effects of invasive zebra mussels increasing water clarity.
Impact
- Extensive surface scums across the lough
- Recreational restrictions
- Additional treatment burden for drinking water abstraction
- Ecological damage and dog deaths attributed to toxin exposure
Response
Monitoring, public warnings and development of a nutrient action programme.
Aftermath
The most prominent current UK example of agricultural nutrient loading producing a visible, sustained water quality failure, and of the long lag between nutrient reduction and recovery.
Relationships
- Located in: Northern Ireland
Related intelligence
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Sources
- Peer-reviewed scientific literature — Open-access hydrology, water chemistry and water use research. Public but restricted · Publisher terms — public access, reuse not clearly granted