Predicting Discharge Water Quality from Steeprock Pit Lakes in Atikokan, Ontario, Canada

摘要

Caland and Hogarth Pit Lakes were formed after flooding of the Steep Rock iron mines near Atikokan, Ontario, Canada. The two pit lakes continue to fill and will eventually join and empty into an adjacent river system. A model was developed to predict the water quality at outflow. At this time, the pit lakes will be approximately 400 m in depth, the oligotrophic freshwater lens in Caland will disappear, and the water will be degraded to more closely resemble the monimolimnion in Hogarth which has sulfate levels up to 2000 mg.l~(-1). Experiments with wetland plant species determined that outflow water quality could be improved by constructing wetlands in the discharge zone. Of the four plant species examined, Carex sp. was able to concentrate the greatest amounts of S, Al, Cu, Fe, Ni, Sr, and Zn in its tissue and make the greatest improvement in water quality.