Heavy metals such as manganese, iron, copper, and zinc are essential macronutrients for life, however in high concentrations can be poisonous. The main source of heavy metals within our catchments is from abandoned metal mines, it is thought that minewater accounts for 2% of the reasons waters fail to meet quality standards.
After the mine closed and pumping stopped, the mine workings flooded and the water level recovered until it reached a point where it could contaminate groundwater and also drain freely to surface water. Waters leaching from these long abandoned mines can be contaminated with iron, zinc, lead, cadmium, aluminium, manganese and copper and can also be quite acidic. Minewater pollution can have significant effects on the ecology, most heavy metals bioaccumulate, mean they can’t be broken down naturally. However, some places with a very long history of contamination, wildlife has adapted to the pollution to some extent.