The environmental impact of large-scale industrial activity can be felt long after the activity stops. A new study published in the journal ScienceDirect found that decades after the closure of the Giant Mine — located on the outskirts of Yellowknife in the Northwest Territories province of Canada — small animals still carried significant amounts of toxic chemicals, such as arsenic, in their fur. While high levels of arsenic had been documented in the soil, plants and fish near the Giant Mine, scientists had not previously documented the impact on small mammals. Understanding the potential toxicity of these animals is important, as these creatures are still hunted for their furs and food, through which humans could also absorb the dangerous chemicals.
The Giant Mine near Yellowknife contributed to the arsenic contamination of the surrounding area through its 55 years as an active gold mine. To extract gold from ore, it must be heated at extremely high temperatures. This process creates a toxic compound called arsenic trioxide, about 237,000 tons of which is buried underground near the mine site. Arsenic is naturally found within the Earth, often in gold-holding rocks. While arsenic usually seeps slowly into the environment through steady erosion of the rock, gold mining accelerates that process.
Small mammals like the snowshoe hare often serve as early warning signs of an environment’s contamination. Because of the animal’s limited habitat range and diet of ground plants, the contaminant levels are often higher than other organisms. When snowshoe hares who lived near Giant Mine were tested for levels of arsenic, researchers found that their arsenic levels were 20 to 50 times higher than hares who lived elsewhere. Arsenic-contaminated wildlife often suffer from osteoporosis, neurological damage, reproductive issues and chronic metabolic disease. Scientists are most concerned that the arsenic contamination will find its way up the food chain, harming larger mammals, including humans.