Pollution from Mines
The rivers Swale, Ure, Nidd, Wharfe, and Ouse have a long legacy of metal mining. While the mines are no longer active, abandoned sites continue to pollute local waters with harmful metals such as zinc, lead, copper and cadmium.
What is minewater pollution?
When mines were operational, groundwater was pumped out to keep workings dry. Once mines closed, pumping stopped, the tunnels filled with water and contaminated minewater began to flow into rivers, streams and groundwater. This water is often acidic and rich in metals, damaging aquatic habitats and water quality.
Sources of pollution
- Underground minewater: Flooded tunnels release polluted water containing iron, zinc, lead, cadmium, manganese and copper.
- Surface mine waste: Rainfall washes metals from abandoned waste heaps and sediments into rivers, spreading contamination for miles downstream.
- Floodplain sediments: Historic pollution, particularly along the River Swale, has left heavy metals in sediments that could be re-released during flooding.
Environmental impact
Minewater pollution accounts for around 2% of water quality failures in local catchments. High levels of zinc and other metals:
- Reduces biodiversity by harming fish and aquatic invertebrates.
- Alters ecosystems, although some wildlife has adapted over centuries.
- Threatens drinking water supplies if contamination enters aquifers.
Tackling minewater pollution
The Environment Agency and Mining Remediation Authority are working to prevent further deterioration of water quality caused by abandoned mines. Continuous monitoring and targeted interventions are essential to protect rivers, wildlife and communities from this legacy of mining.
*Source: Environment Agency’s Challenges and Choices.
