According to a myriad of studies performed by the US Geological Survey and published within the journal Environmental Toxicity and Chemistry, an unhealthy amount of mercury and selenium are concentrated within the Grand Canyon and this might disrupt the food web for fish and wildlife in the area.

Dr. David Walters, a USGS research ecologist and the lead author of the study, said, “Managing exposure risks in the Grand Canyon will be a challenge, because sources and transport mechanisms of mercury and selenium extend far beyond Grand Canyon boundaries,”

From about six sites along the Colorado river, agency researchers gathered samples and data, where they found high levels of mercury and selenium contamination. This was abundant in the fish, invertebrates, and minnows along this region.

Any animals or people who ingest these contaminated animals could have serious health risks.

According to Arizona Daily Sun, the deposits of the mercury and selenium are hard to pin down due to the nature of these chemicals.

While people are pointing at the Navajo Generating Station, which is stationed along the side of Lake Powell, as well as other such coal fired power plants, that might not be the case.

Mercury can stay in the atmosphere for up to six months after it is initially emitted and, according to Ted Kennedy, a USGS researcher at the Grand Canyon Monitoring and Research Center in Flagstaff, who was a co-author on the study, tracking the source is going to be much more difficult than looking for a singular source.

“Navajo Generating Station is a potential source, but there’s a lot of atmospheric mercury out there even before you consider Navajo,” Kennedy said.