@EPA: Bonita Peak Mining District Human Health Risk Assessment

On April 7, 2016, the Environmental Protection Agency proposed adding the “Bonita Peak Mining District” to the National Priorities List, making it eligible for Superfund. Forty-eight mine portals and tailings piles are “under consideration” to be included. The Gold King Mine will almost certainly be on the final list, as will the nearby American Tunnel. The Mayflower Mill #4 tailings repository, just outside Silverton, is another likely candidate, given that it appears to be leaching large quantities of metals into the Animas River. What Superfund will entail for the area beyond that, and when the actual cleanup will begin, remains unclear.
Eric Baker

Click here to read the report. Here’s the introduction:

The Bonita Peak Mining District Superfund Site (Site) is located in southwestern Colorado. The Site consists of 48 historic mines or mining-related sources where ongoing releases of metal- laden water and sediments are occurring within the Mineral Creek, Cement Creek, and Upper Animas River drainages in San Juan County. Drainages within the Site contain over 400 abandoned or inactive mines, where large- to small-scale mining operations occurred. San Juan County is comprised of 10 historic mining districts (Colorado Geological Survey 2017). Historic mining districts within the Mineral Creek, Cement Creek, and Upper Animas River drainages include Animas, Animas Forks, Cement Creek, Eureka, Ice Lake Basin, and Mineral Point. Hereafter, the term “mining districts” or “Site” is used to refer to the mining districts within these three drainages. This document is a baseline human health risk assessment (HHRA) for the mining districts. The purpose of this document is to characterize the potential risks to humans, both now and in the future, from exposures to contaminants that may be present in the mining districts, assuming that no steps are taken to remediate the environment or to reduce human contact with contaminated environmental media. The mining districts are primarily used by humans for recreational, occupational, and tribal purposes. The receptor populations of interest for the risk assessment included campers, hikers, hunters, recreational fishermen, all-terrain vehicle (ATV) guides, ATV recreational riders, and county road workers. An addendum to this risk assessment will be developed to evaluate tribal exposures once the necessary exposure data are available.

The results of this assessment are intended to help inform risk managers and the public about current and potential future health risks to humans that may occur as a result of exposure to mining-related contaminants due to recreational and occupational activities, and to help determine if there is a need for action to protect public health at the Site. Site managers will also consider the results of the ecological risk assessment and any regulatory requirements in determining appropriate remedial actions for the Site. As appropriate, discussions and recommendations on how to manage potential risks will be provided in the Feasibility Study. The identification of remedial action levels, which will guide future remediation efforts, will be provided in the Record of Decision.

The methods used to evaluate risks in this HHRA are consistent with current guidelines for human health risk assessment provided by the U.S. Environmental Protection Agency (EPA) for use at Superfund sites (EPA 1989, 1991a, 1991b, 1992, 1997, 2002a, 2002b, 2002c, 2004, 2009a).

From The Durango Herald (Jonathan Romeo):

Despite findings, agency says cleanup remains a priority

A new study has found no serious risk to human health stemming from mines included in a Superfund site around Silverton, according to the Environmental Protection Agency.

“This is a good news story,” said Christina Progess, Superfund remedial project manager. “And it’s a really important milestone for the project that paints a more full picture in terms of what cleanup work needs to be done.”

[…]

As part of the Superfund process, the EPA must evaluate the risks contamination slated for cleanup has on human health. In the case of Bonita Peak, exposure to mine waste through incidental ingestion and inhalation stood as the highest possibilities for people who visit the area.

But, for the most part, the study showed there doesn’t seem to be much risk to human health…

“Overall, there’s a lot of good news in here,” Progess said. “It doesn’t impact the local tourism industry, and folks working out in the district aren’t at risk from a human health standpoint. But (the study) also helps us highlight there are some areas that people come in contact with it.”

While Superfund sites with clear and significant human health risks receive priority within the EPA for funding, Progess said she doesn’t expect the study’s findings to affect Bonita Peak.

“Bonita Peak has always been and continues to be one of the administration’s top priority Superfund sites in the nation,” she said. “I don’t anticipate (funding) being a concern.”

In April, the EPA released a study assessing risks to aquatic habitats, which showed that in areas where water had low pH and elevated metals, fish and other aquatic life populations were highly impaired or nonexistent.

The study helped EPA identify four areas where the agency would like to improve water quality in the Animas River watershed to the point where restoration of aquatic life could be achievable.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.