Study: Mercury in the Rockies and How it Might Affect Montana

Mountain snowpacks build up stores of water that will supply communities across the American West throughout the long dry season.

A new study finds that mines in the Pacific Northwest, Idaho, and Montana are likely the source of mercury and other contaminants in Rocky Mountain snowpack. So says a new study published in the May issue of Environmental Pollution.

The journal says researchers examined contamination levels for mercury, zinc, cadmium and antimony from nearly 50 sites in the Rocky Mountains. A team from the Desert Research Institute says they found higher levels of metal contaminants in the northern Rockies and identified mines in the Pacific Northwest, Idaho, and Montana as the likely source by following winter storms back in time. It is one of the first studies to look at metal contamination across the greater Rocky Mountains.

As storms carry snow to the Rocky Mountains, they are also bringing mercury and other contaminants from mines in the region. The publication says that research helps scientists "understand how contaminants are spread by atmospheric circulation and has implications for snowpack preservation and illuminating the lasting environmental impact of mining activities."

Although contamination levels were found to be within guidelines set by the EPA for both drinking water and aquatic life,  dust can accelerate snowmelt as it decreases the  snowpack's reflection.

The data can also provide critical information about how environmental contaminants and dust are distributed by the atmosphere.

The study included first an understanding of the amount of metal contamination making its way to the region. Snow samples were collected from 48 sites throughout the Rocky Mountains, then researchers measured metal concentrations in each sample. By comparing the amounts of purely dust-sourced metals to those that result from both dust and industrial activities like mining, the scientists determined how much metal contamination stemmed from human activities.

An examination of EPA Superfund sites uncovered historical sites that could also be sources of contamination.

Many more details on the study can be found here.